Sample records for gamma knife radiosurgery

  1. Dynamic gamma knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Luan, Shuang; Swanson, Nathan; Chen, Zhe; Ma, Lijun

    2009-03-01

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C™ and Perfexion™ units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and the

  2. Embolization with Gamma Knife Radiosurgery of Giant Intracranial Arteriovenous Malformations.

    PubMed

    Chun, Dong Hyun; Kim, Moo Seong; Kim, Sung Tae; Paeng, Sung Hwa; Jeong, Hae Woong; Lee, Won Hee

    2016-01-01

    Giant arteriovenous malformations (i.e., those greater than 6 cm maximum diameter or volume > 33 cc) are difficult to treat and often carry higher treatment morbidity and mortality rates. In our study, we reviewed the angiographic results and clinical outcomes for 11 patients with giant arteriovenous malformations who were treated between 1994 and 2012. The patients selected included 9 males (82%) and 2 females (18%). Their presenting symptoms were hemorrhage (n=2; 18%), seizure (n=7; 64%), and headache (n=2; 12%). Nine patients were Spetzler-Martin Grade III, 2 were Spetzler-Martin Grade IV. The mean arteriovenous malformation volume was 41 cc (33-52 cc). The mean age of the patients was 45.1 years (24-57 years) and the mean radiation dose delivered to the margin of the nidus was 14.2 Gy. Ten patients received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery, 1 patient received pre-Gamma Knife radiosurgery embolization and Gamma Knife radiosurgery twice and the interval between Gamma Knife radiosurgeries was 3 months. The complete obliteration rate following Gamma Knife radiosurgery was 36%, subtotal obliteration ( > 70% decreased size of nidus) was 36%, and partial obliteration was 28%. One patient experienced a small hemorrhage after embolization. Combined embolization and Gamma Knife radiosurgery showed successful obliteration of the arteriovenous malformation nidus. The use of embolization to initially reduce nidus size followed by Gamma Knife radiosurgery improves the treatment results. Repeated Gamma Knife radiosurgery should be a treatment option when there is a small nidus remnant.

  3. Treatment of epidermoid tumors with gamma knife radiosurgery: Case series.

    PubMed

    Vasquez, Javier A Jacobo; Fonnegra, Julio R; Diez, Juan C; Fonnegra, Andres

    2016-01-01

    Epidermoid tumors (ETs) are benign lesions that are treated mainly by means of surgical resection, with overall good results. External beam radiotherapy is an alternative treatment for those recurrent tumors, in which a second surgery might not be the best choice for the patient. A little information exists about the effectiveness of gamma knife radiosurgery for the treatment of newly diagnosed and recurrent ETs. We present three cases of ETs treated with gamma knife radiosurgery. Case 1 is a 21-year-old female with an ET located in the left cerebellopontine angle (CPA) with symptoms related to VIII cranial nerve dysfunction. Symptom control was achieved and maintained after single session radiosurgery with gamma knife. Case 2 is a 59-year-old female patient with the history of trigeminal neuralgia secondary to a recurrent ET located in the left CPA. Significant pain improvement was achieved after treatment with gamma knife radiosurgery. Case 3 is a 29-year-old male patient with a CPA ET causing long lasting trigeminal neuralgia, pain relief was achieved in this patient after gamma knife radiosurgery. Long-term symptom relief was achieved in all three cases proving that gamma knife radiosurgery is a good and safe alternative for patients with recurrent or nonsurgically treated ETs.

  4. Failure modes and effects analysis (FMEA) for Gamma Knife radiosurgery.

    PubMed

    Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Flickinger, John; Arai, Yoshio; Vacsulka, Jonet; Feng, Wenzheng; Monaco, Edward; Niranjan, Ajay; Lunsford, L Dade; Huq, M Saiful

    2017-11-01

    Gamma Knife radiosurgery is a highly precise and accurate treatment technique for treating brain diseases with low risk of serious error that nevertheless could potentially be reduced. We applied the AAPM Task Group 100 recommended failure modes and effects analysis (FMEA) tool to develop a risk-based quality management program for Gamma Knife radiosurgery. A team consisting of medical physicists, radiation oncologists, neurosurgeons, radiation safety officers, nurses, operating room technologists, and schedulers at our institution and an external physicist expert on Gamma Knife was formed for the FMEA study. A process tree and a failure mode table were created for the Gamma Knife radiosurgery procedures using the Leksell Gamma Knife Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detection for failure mode (D) were assigned to each failure mode by 8 professionals on a scale from 1 to 10. An overall risk priority number (RPN) for each failure mode was then calculated from the averaged O, S, and D scores. The coefficient of variation for each O, S, or D score was also calculated. The failure modes identified were prioritized in terms of both the RPN scores and the severity scores. The established process tree for Gamma Knife radiosurgery consists of 10 subprocesses and 53 steps, including a subprocess for frame placement and 11 steps that are directly related to the frame-based nature of the Gamma Knife radiosurgery. Out of the 86 failure modes identified, 40 Gamma Knife specific failure modes were caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the Gamma Knife helmets and plugs, the skull definition tools as well as other features of the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all external beam radiation therapy

  5. Cost analysis of Gamma Knife stereotactic radiosurgery.

    PubMed

    Griffiths, Alison; Marinovich, Luke; Barton, Michael B; Lord, Sarah J

    2007-01-01

    Stereotactic radiosurgery (SRS) is used to treat intracranial lesions and vascular malformations as an addition or replacement to whole brain radiotherapy and microsurgery. SRS can be delivered by hardware and software appended to standard linear accelerators (Linacs) or by dedicated systems such as Gamma Knife, which has been proposed as a more accurate and user friendly technology. Internationally, dedicated systems have been funded, despite limitations in evidence. However, some countries including Australia have not recommended additional reimbursement for dedicated systems. This study compares the costs of Linac radiosurgery with Gamma Knife radiosurgery. Due to limited evidence on comparative effects, the economic analysis was restricted to a cost evaluation. The base-case analysis assumed a modified Linac was used only to treat SRS patients. However, because a modified Linac could be used to treat other radiotherapy patients, a second analysis assumed spare time was used to meet other radiotherapy needs, and Linac capital costs were apportioned according to SRS use. The incremental cost of Gamma Knife versus a modified Linac was estimated as AU$209 per patient. This result is sensitive to variations in assumptions. A second analysis proportioning capital costs according to SRS use showed that Gamma Knife may cost up to AU$1673 more per patient. Gamma Knife may be cost competitive only if demand for SRS services is high enough to fully use equipment working time. However, given low patient demand and competing radiotherapy needs, Gamma Knife appears more costly and further evidence of survival or quality of life advantages may be required to justify reimbursement.

  6. Gamma knife radiosurgery in movement disorders: Indications and limitations.

    PubMed

    Higuchi, Yoshinori; Matsuda, Shinji; Serizawa, Toru

    2017-01-01

    Functional radiosurgery has advanced steadily during the past half century since the development of the gamma knife technique for treating intractable cancer pain. Applications of radiosurgery for intracranial diseases have increased with a focus on understanding radiobiology. Currently, the use of gamma knife radiosurgery to ablate deep brain structures is not widespread because visualization of the functional targets remains difficult despite the increased availability of advanced neuroimaging technology. Moreover, most existing reports have a small sample size or are retrospective. However, increased experience with intraoperative neurophysiological evaluations in radiofrequency thalamotomy and deep brain stimulation supports anatomical and neurophysiological approaches to the ventralis intermedius nucleus. Two recent prospective studies have promoted the clinical application of functional radiosurgery for movement disorders. For example, unilateral gamma knife thalamotomy is a potential alternative to radiofrequency thalamotomy and deep brain stimulation techniques for intractable tremor patients with contraindications for surgery. Despite the promising efficacy of gamma knife thalamotomy, however, these studies did not include sufficient follow-up to confirm long-term effects. Herein, we review the radiobiology literature, various techniques, and the treatment efficacy of gamma knife radiosurgery for patients with movement disorders. Future research should focus on randomized controlled studies and long-term effects. © 2016 International Parkinson and Movement Disorder Society. © 2016 International Parkinson and Movement Disorder Society.

  7. Gamma knife radiosurgery for cerebellopontine angle epidermoid tumors.

    PubMed

    El-Shehaby, Amr M N; Reda, Wael A; Abdel Karim, Khaled M; Emad Eldin, Reem M; Nabeel, Ahmed M

    2017-01-01

    Intracranial epidermoid tumors are commonly found in the cerebellopontine angle where they usually present with either trigeminal neuralgia or hemifacial spasm. Radiosurgery for these tumors has rarely been reported. The purpose of this study is to assess the safety and clinical outcome of the treatment of cerebellopontine epidermoid tumors with gamma knife radiosurgery. This is a retrospective study involving 12 patients harboring cerebellopontine angle epidermoid tumors who underwent 15 sessions of gamma knife radiosurgery. Trigeminal pain was present in 8 patients and hemifacial spasm in 3 patients. All cases with trigeminal pain were receiving medication and still uncontrolled. One patient with hemifacial spasm was medically controlled before gamma knife and the other two were not. Two patients had undergone surgical resection prior to gamma knife treatment. The median prescription dose was 11 Gy (10-11 Gy). The tumor volumes ranged from 3.7 to 23.9 cc (median 10.5 cc). The median radiological follow up was 2 years (1-5 years). All tumors were controlled and one tumor shrank. The median clinical follow-up was 5 years. The trigeminal pain improved or disappeared in 5 patients, and of these, 4 cases stopped their medication and one decreased it. The hemifacial spasm resolved in 2 patients who were able to stop their medication. Facial palsy developed in 1 patient and improved with conservative treatment. Transient diplopia was also reported in 2 cases. Gamma knife radiosurgery provides good clinical control for cerebellopontine angle epidermoid tumors.

  8. A microcosting study of microsurgery, LINAC radiosurgery, and gamma knife radiosurgery in meningioma patients

    PubMed Central

    van Putten, Erik; Nijdam, Wideke M.; Hanssens, Patrick; Beute, Guus N.; Nowak, Peter J.; Dirven, Clemens M.; Hakkaart-van Roijen, Leona

    2010-01-01

    The aim of the present study is to determine and compare initial treatment costs of microsurgery, linear accelerator (LINAC) radiosurgery, and gamma knife radiosurgery in meningioma patients. Additionally, the follow-up costs in the first year after initial treatment were assessed. Cost analyses were performed at two neurosurgical departments in The Netherlands from the healthcare providers’ perspective. A total of 59 patients were included, of whom 18 underwent microsurgery, 15 underwent LINAC radiosurgery, and 26 underwent gamma knife radiosurgery. A standardized microcosting methodology was employed to ensure that the identified cost differences would reflect only actual cost differences. Initial treatment costs, using equipment costs per fraction, were €12,288 for microsurgery, €1,547 for LINAC radiosurgery, and €2,412 for gamma knife radiosurgery. Higher initial treatment costs for microsurgery were predominantly due to inpatient stay (€5,321) and indirect costs (€4,350). LINAC and gamma knife radiosurgery were equally expensive when equipment was valued per treatment (€2,198 and €2,412, respectively). Follow-up costs were slightly, but not significantly, higher for microsurgery compared with LINAC and gamma knife radiosurgery. Even though initial treatment costs were over five times higher for microsurgery compared with both radiosurgical treatments, our study gives indications that the relative cost difference may decrease when follow-up costs occurring during the first year after initial treatment are incorporated. This reinforces the need to consider follow-up costs after initial treatment when examining the relative costs of alternative treatments. PMID:20526795

  9. Gamma knife radiosurgery for cerebellopontine angle epidermoid tumors

    PubMed Central

    El-Shehaby, Amr M. N.; Reda, Wael A.; Abdel Karim, Khaled M.; Emad Eldin, Reem M.; Nabeel, Ahmed M.

    2017-01-01

    Background: Intracranial epidermoid tumors are commonly found in the cerebellopontine angle where they usually present with either trigeminal neuralgia or hemifacial spasm. Radiosurgery for these tumors has rarely been reported. The purpose of this study is to assess the safety and clinical outcome of the treatment of cerebellopontine epidermoid tumors with gamma knife radiosurgery. Methods: This is a retrospective study involving 12 patients harboring cerebellopontine angle epidermoid tumors who underwent 15 sessions of gamma knife radiosurgery. Trigeminal pain was present in 8 patients and hemifacial spasm in 3 patients. All cases with trigeminal pain were receiving medication and still uncontrolled. One patient with hemifacial spasm was medically controlled before gamma knife and the other two were not. Two patients had undergone surgical resection prior to gamma knife treatment. The median prescription dose was 11 Gy (10–11 Gy). The tumor volumes ranged from 3.7 to 23.9 cc (median 10.5 cc). Results: The median radiological follow up was 2 years (1–5 years). All tumors were controlled and one tumor shrank. The median clinical follow-up was 5 years. The trigeminal pain improved or disappeared in 5 patients, and of these, 4 cases stopped their medication and one decreased it. The hemifacial spasm resolved in 2 patients who were able to stop their medication. Facial palsy developed in 1 patient and improved with conservative treatment. Transient diplopia was also reported in 2 cases. Conclusion: Gamma knife radiosurgery provides good clinical control for cerebellopontine angle epidermoid tumors. PMID:29184709

  10. Long-Term Results of Gamma Knife Radiosurgery for Intracranial Meningioma

    PubMed Central

    Jang, Chang Ki; Jung, Hyun Ho; Chang, Jong Hee; Chang, Jin Woo; Park, Yong Gou

    2015-01-01

    Background The predominant treatment modality for meningioma is surgical resection. However, gamma knife radiosurgery is also an important treatment modality for meningioma that is small or cannot be completely removed because of its location. In this study, we evaluated the effectiveness and long-term results of radiosurgical treatment for meningioma in our institution. Methods We studied 628 patients (130 men and 498 women) who underwent gamma knife radiosurgery for intracranial meningioma, which is radiologically diagnosed, from Jan 2008 to Nov 2012. We included patients with single lesion meningioma, and followed up after 6 months with imaging, and then at 24 months with a clinical examination. Patients with high-grade meningioma or multiple meningiomas were excluded. We analyzed each of the factors associated with progression free survival. The median patient's age was 56.8 years. Maximal dosage was 27.8 Gy and marginal dosage was 13.9 Gy. Results The overall tumor control rate was 95%. Twenty-eight patients (4.4%) showed evidence of tumor recurrence. Ninety-eight patients (15%) developed peritumoral edema (PTE) after gamma-knife surgery; two of them (2%) underwent surgical resections due to PTE. Nine patients had craniotomy and tumor removal after gamma knife surgery. Conclusion Gamma knife surgery for intracranial meningioma has proven to be a safe and effective treatment tool with successful long-term outcomes. Gamma knife radiosurgery can be especially effective in cases of remnant meningioma after surgical resection or where PTE is not present. PMID:26605265

  11. Long-Term Results of Gamma Knife Radiosurgery for Intracranial Meningioma.

    PubMed

    Jang, Chang Ki; Jung, Hyun Ho; Chang, Jong Hee; Chang, Jin Woo; Park, Yong Gou; Chang, Won Seok

    2015-10-01

    The predominant treatment modality for meningioma is surgical resection. However, gamma knife radiosurgery is also an important treatment modality for meningioma that is small or cannot be completely removed because of its location. In this study, we evaluated the effectiveness and long-term results of radiosurgical treatment for meningioma in our institution. We studied 628 patients (130 men and 498 women) who underwent gamma knife radiosurgery for intracranial meningioma, which is radiologically diagnosed, from Jan 2008 to Nov 2012. We included patients with single lesion meningioma, and followed up after 6 months with imaging, and then at 24 months with a clinical examination. Patients with high-grade meningioma or multiple meningiomas were excluded. We analyzed each of the factors associated with progression free survival. The median patient's age was 56.8 years. Maximal dosage was 27.8 Gy and marginal dosage was 13.9 Gy. The overall tumor control rate was 95%. Twenty-eight patients (4.4%) showed evidence of tumor recurrence. Ninety-eight patients (15%) developed peritumoral edema (PTE) after gamma-knife surgery; two of them (2%) underwent surgical resections due to PTE. Nine patients had craniotomy and tumor removal after gamma knife surgery. Gamma knife surgery for intracranial meningioma has proven to be a safe and effective treatment tool with successful long-term outcomes. Gamma knife radiosurgery can be especially effective in cases of remnant meningioma after surgical resection or where PTE is not present.

  12. The current role of Gamma Knife radiosurgery in the management of intracranial haemangiopericytoma.

    PubMed

    Spina, Alfio; Boari, Nicola; Gagliardi, Filippo; Donofrio, Carmine A; Franzin, Alberto; Mortini, Pietro

    2016-04-01

    Haemangiopericytomas (HPCs) are rare tumours characterised by aggressive behaviour with tendency to local recurrence and to metastasise. WHO grade II and grade III tumours show different progression-free survival and overall survival rates. Gross total tumour resection is still considered the treatment of choice. Adjuvant radiation therapies represent an option in the treatment strategy regardless the extent of resection. Based on this consideration, Gamma Knife radiosurgery has been introduced either as a primary treatment or as an adjuvant treatment for residual or recurrent tumours. A systematic search was performed on PubMed, Web of Science and Google Scholar for clinical series reporting Gamma Knife radiosurgery, Cyberknife and Linear Accelerator (LINAC) for the management of intracranial HPCs. Fourteen studies focusing on the effects of Gamma Knife radiosurgery for intracranial HPCs were included. Four studies reported data on Cyberknife radiosurgery and LINAC. A total of 208 patients harbouring 366 tumours have been reported. Patient's features, radiosurgical treatment characteristics and follow-up data of the pertinent literature have been critically revised. Gamma Knife radiosurgery and the other radiosurgical techniques represent a feasible and effective therapy in the management of HPCs. Tumour control and survival rate are comparable to those reported for radiotherapy. Further studies should be focused to define the exact role of Gamma Knife radiosurgery in the management of HPCs.

  13. Leksell Gamma Knife radiosurgery of the jugulotympanic glomus tumor: long-term results.

    PubMed

    Liscak, Roman; Urgosik, Dusan; Chytka, Tomas; Simonova, Gabriela; Novotny, Josef; Vymazal, Josef; Guseynova, Khumar; Vladyka, Vilibald

    2014-12-01

    Glomus tumors usually display indolent behavior, and the effectiveness of radiation in stopping their growth can be assessed after long-term follow-up. Currently only midterm results of radiosurgery are available, so the authors included patients treated by Gamma Knife at least 10 years ago in this study to obtain a perspective of long-term results. During the period from 1992 to 2003, the Gamma Knife was used to treat 46 patients with glomus tumors. The age of the patients ranged from 21 to 79 years (median 56 years). Gamma Knife radiosurgery was the primary treatment in 17 patients (37%). Open surgery preceded radiosurgery in 46% of cases, embolization in 17%, and fractionated radiotherapy in 4%. The volume of the tumor ranged from 0.2 to 24.3 cm(3) (median 3.6 cm(3)). The minimal dose to the tumor margin ranged between 10 and 30 Gy (median 20 Gy). One patient was lost for follow-up after radiosurgery. Clinical follow-up was available in 45 patients and 44 patients were followed with MRI in a follow-up period that ranged from 12 to 217 months (median 118 months). Neurological deficits improved in 19 (42%) of 45 patients and deteriorated in 2 patients (4%). Tumor size decreased in 34 (77%) of 44 patients with imaging follow-up, while an increase in volume was observed in 1 patient (2%) 182 months after radiosurgery and Gamma Knife treatment was repeated. One patient underwent another Gamma Knife treatment for secondary induced meningioma close to the glomus tumor 98 months after initial radiosurgical treatment. Seven patients died 22-96 months after radiosurgery (median 48 months), all for unrelated reasons. Radiosurgery has proved to be a safe treatment with a low morbidity rate and a reliable long-term antiproliferative effect.

  14. Clinical outcomes of gamma knife radiosurgery in the salvage treatment of patients with recurrent high-grade glioma.

    PubMed

    Elaimy, Ameer L; Mackay, Alexander R; Lamoreaux, Wayne T; Demakas, John J; Fairbanks, Robert K; Cooke, Barton S; Lamm, Andrew F; Lee, Christopher M

    2013-12-01

    Previously published randomized evidence did not report a survival advantage for patients diagnosed with grade IV glioma who were treated with stereotactic radiosurgery followed by external beam radiation therapy and chemotherapy when compared to patients treated with external beam radiation therapy and chemotherapy alone. In recent years, gamma knife radiosurgery has become increasingly popular as a salvage treatment modality for patients diagnosed with recurrent high-grade glioma. The purpose of this article is to review the efficacy of gamma knife radiosurgery for patients who suffer from this malignancy. Retrospective, prospective, and randomized clinical studies published between the years 2000 and 2012 analyzing gamma knife radiosurgery for patients with high-grade glioma were reviewed. After assessing patient age, Karnofsky performance status, tumor histology, and extent of resection, gamma knife radiosurgery is a viable, minimally invasive treatment option for patients diagnosed with recurrent high-grade glioma. The available prospective and retrospective evidence suggests that gamma knife radiosurgery provides patients with a high local tumor control rate and a median survival after tumor recurrence ranging from 13 to 26 months. Gamma knife radiosurgery followed by chemotherapy for recurrent high-grade glioma may provide select patients with increased levels of survival. However, further investigation into this matter is needed due to the limited number of published reports. Additional clinical research is also needed to analyze the efficacy and radiation-related toxicities of fractionated gamma knife radiosurgery due to its potential to limit treatment-associated morbidity. Gamma knife radiosurgery is a safe and effective treatment option for select patients diagnosed with recurrent high-grade glioma. Although treatment outcomes have improved, further evidence in the form of phase III randomized trials is needed to assess the durability of treating

  15. Gamma Knife radiosurgery in pituitary adenomas: Why, who, and how to treat?

    PubMed

    Castinetti, Frederic; Brue, Thierry

    2010-08-01

    Pituitary adenomas are benign tumors that can be either secreting (acromegaly, Cushing's disease, prolactinomas) or non-secreting. Transsphenoidal neurosurgery is the gold standard treatment; however, it is not always effective. Gamma Knife radiosurgery is a specific modality of stereotactic radiosurgery, a precise radiation technique. Several studies reported the efficacy and low risk of adverse effects induced by this technique: in secreting pituitary adenomas, hypersecretion is controlled in about 50% of cases and tumor volume is stabilized or decreased in 80-90% of cases, making Gamma Knife a valuable adjunctive or first-line treatment. As hormone levels decrease progressively, the main drawback is the longer time to remission (12-60 months), requiring an additional treatment during this period. Hypopituitarism is the main side effect, observed in 20-40% cases. Gamma Knife is thus useful in the therapeutic algorithms of pituitary adenomas in well-defined indications, mainly low secreting small lesions well identified on magnetic resonance imaging (MRI).

  16. Clinical Evaluation of Targeting Accuracy of Gamma Knife Radiosurgery in Trigeminal Neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Massager, Nicolas; Abeloos, Laurence; Devriendt, Daniel

    2007-12-01

    Purpose: The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgical treatment with the Leksell Gamma Knife for trigeminal neuralgia. We also studied the applied radiation dose within the area of focal contrast enhancement on the trigeminal nerve root following radiosurgery. Methods and Materials: From an initial group of 78 patients with trigeminal neuralgia treated with gamma knife radiosurgery using a 90-Gy dose, we analyzed a subgroup of 65 patients for whom 6-month follow-up MRI showed focal contrast enhancement of the trigeminal nerve. Follow-up MRI was spatially coregistered to the radiosurgicalmore » planning MRI. Target accuracy was assessed from deviation of the coordinates of the intended target compared with the center of enhancement on postoperative MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated. Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was 0.91 mm in Euclidean space. The radiation doses fitting within the borders of the contrast enhancement of the trigeminal nerve root ranged from 49 to 85 Gy (median value, 77 {+-} 8.7 Gy). Conclusions: The median deviation found in clinical assessment of gamma knife treatment for trigeminal neuralgia is low and compatible with its high rate of efficiency. Focal enhancement of the trigeminal nerve after radiosurgery occurred in 83% of our patients and was not associated with clinical outcome. Focal enhancement borders along the nerve root fit with a median dose of 77 {+-} 8.7 Gy.« less

  17. Gamma Knife Radiosurgery as a Therapeutic Strategy for Intracranial Sarcomatous Metastases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Flannery, Thomas; Department of Radiation Oncology, University of Pittsburgh School of Medicine and the University of Pittsburgh Medical Center, Pittsburgh, PA; Department of Neurosurgery, Royal Hospitals Trust, Belfast, Northern Ireland

    2010-02-01

    Purpose: To determine the indication and outcomes for Gamma Knife stereotactic radiosurgery (GKSRS) in the care of patients with intracranial sarcomatous metastases. Methods and Materials: Data from 21 patients who underwent radiosurgery for 60 sarcomatous intracranial metastases (54 parenchymal and 6 dural-based) were studied. Nine patients had radiosurgery for solitary tumors and 12 for multiple tumors. The primary pathology was metastatic leiomyosarcoma (4 patients), osteosarcoma (3 patients), soft-tissue sarcoma (5 patients), chondrosarcoma (2 patients), alveolar soft part sarcoma (2 patients), and rhabdomyosarcoma, Ewing's sarcoma, liposarcoma, neurofibrosarcoma, and synovial sarcoma (1 patient each). Twenty patients received multimodality management for their primarymore » tumor, and 1 patient had no evidence of systemic disease. The mean tumor volume was 6.2 cm{sup 3} (range, 0.07-40.9 cm{sup 3}), and a median margin dose of 16 Gy was administered. Three patients had progressive intracranial disease despite fractionated whole-brain radiotherapy before SRS. Results: A local tumor control rate of 88% was achieved (including patients receiving boost, up-front, and salvage SRS). New remote brain metastases developed in 7 patients (33%). The median survival after diagnosis of intracranial metastasis was 16 months, and the 1-year survival rate was 61%. Conclusions: Gamma Knife radiosurgery was a well-tolerated and initially effective therapy in the management of patients with sarcomatous intracranial metastases. However, many patients, including those who also received fractionated whole-brain radiotherapy, developed progressive new brain disease.« less

  18. WE-A-304-02: Strategies and Technologies for Cranial Radiosurgery Planning: Gamma Knife

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schlesinger, D.

    2015-06-15

    The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Futuremore » directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.« less

  19. Single-session Gamma Knife radiosurgery for optic pathway/hypothalamic gliomas.

    PubMed

    El-Shehaby, Amr M N; Reda, Wael A; Abdel Karim, Khaled M; Emad Eldin, Reem M; Nabeel, Ahmed M

    2016-12-01

    OBJECTIVE Because of their critical and central location, it is deemed necessary to fractionate when considering irradiating optic pathway/hypothalamic gliomas. Stereotactic fractionated radiotherapy is considered safer when dealing with gliomas in this location. In this study, the safety and efficacy of single-session stereotactic radiosurgery for optic pathway/hypothalamic gliomas were reviewed. METHODS Between December 2004 and June 2014, 22 patients with optic pathway/hypothalamic gliomas were treated by single-session Gamma Knife radiosurgery. Twenty patients were available for follow-up for a minimum of 1 year after treatment. The patients were 5 to 43 years (median 16 years) of age. The tumor volume was 0.15 to 18.2 cm 3 (median 3.1 cm 3 ). The prescription dose ranged from 8 to 14 Gy (median 11.5 Gy). RESULTS The mean follow-up period was 43 months. Five tumors involved the optic nerve only, and 15 tumors involved the chiasm/hypothalamus. Two patients died during the follow-up period. The tumors shrank in 12 cases, remained stable in 6 cases, and progressed in 2 cases, thereby making the tumor control rate 90%. Vision remained stable in 12 cases, improved in 6 cases, and worsened in 2 cases in which there was tumor progression. Progression-free survival was 83% at 3 years. CONCLUSIONS The initial results indicate that single-session Gamma Knife radiosurgery is a safe and effective treatment option for optic pathway/hypothalamic gliomas.

  20. Repeat Gamma-Knife Radiosurgery for Refractory or Recurrent Trigeminal Neuralgia with Consideration About the Optimal Second Dose.

    PubMed

    Park, Seong-Cheol; Kwon, Do Hoon; Lee, Do Hee; Lee, Jung Kyo

    2016-02-01

    To investigate adequate radiation doses for repeat Gamma Knife radiosurgery (GKS) for trigeminal neuralgia in our series and meta-analysis. Fourteen patients treated by ipsilateral repeat GKS for trigeminal neuralgia were included. Median age of patients was 65 years (range, 28-78), the median target dose, 140-180). Patients were followed a median of 10.8 months (range, 1-151) after the second gamma-knife surgery. Brainstem dose analysis and vote-counting meta-analysis of 19 studies were performed. After the second gamma-knife radiosurgeries, pain was relieved effectively in 12 patients (86%; Barrow Neurological Institute Pain Intensity Score I-III). Post-gamma-knife radiosurgery trigeminal nerve deficits were mild in 5 patients. No serious anesthesia dolorosa was occurred. The second GKS radiation dose ≤ 60 Gy was significantly associated with worse pain control outcome (P = 0.018 in our series, permutation analysis of variance, and P = 0.009 in the meta-analysis, 2-tailed Fisher's exact test). Cumulative dose ≤ 140-150 Gy was significantly associated with poor pain control outcome (P = 0.033 in our series and P = 0.013 in the meta-analysis, 2-tailed Fisher's exact test). A cumulative brainstem edge dose >12 Gy tended to be associated with trigeminal nerve deficit (P = 0.077). Our study suggests that the second GKS dose is a potentially important factor. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. The gamma knife in ophthalmology. Part One--Uveal melanoma.

    PubMed

    Wygledowska-Promieńska, Dorota; Jurys, Małgorzata; Wilczyński, Tomasz; Drzyzga, Łukasz

    2014-01-01

    The Gamma Knife was designed by Lars Leksell in the early 1950's. It gave rise to a new discipline of medicine--stereotactic radiosurgery. Primarily dedicated to neurosurgery, the Gamma Knife has become an alternative, widely used surgery technique. According to Elekta's statistics, approximately 60,000 people are treated with Leksell Gamma Knife every year and it is the most extensively studied stereotactic radiosurgery system in the world. The Leksell Gamma Knife can also be used in ophthalmology. The gamma ray beam concentration enables effective treatment of uveal melanoma, choroidal hemangioma, orbital tumors or even choroidal neovascularization. The virtue of Leksell Gamma Knife is its extreme precision, non-invasiveness and the possibility of outpatient treatment, which significantly reduces costs and diminishes post-operative complications. Innovative solutions shorten a single session to a minimum, which is very comfortable and safe for both staff and patients. Advantages and possible side effects of gamma knife radiosurgery are well-documented in the professional literature. The objective of this review is to present the recognized applications of Leksell Gamma Knife in ophthalmology.

  2. Review of the poster "Dosimetric comparison of gamma knife radiosurgery vs. 125I plaque brachytherapy in a cohort of choroidal melanomas".

    PubMed

    Odell, Kelly R

    2009-01-01

    Historically, treatment for choroidal melanomas was surgical enucleation. Currently, treatment methods such as stereotactic radiosurgery and brachytherapy are being used to spare the eye. The poster "Dosimetric Comparison of Gamma Knife Radiosurgery vs. I-125 Plaque Brachytherapy in a Cohort of Choroidal Melanomas" presented at ASTRO 2007 by Anderson et al. provides a comparison of these methods. The dose to disk, fovea and lens in 29 patients from a simulated I-125 treatment and a delivered Gamma Knife radiosurgery was compared. Thirty Gy was prescribed to the 50% Isodose line in the radiosurgery and 85 Gy was prescribed to the apex of the tumor in the I-125 simulation. It was found that the Gamma Knife spares the disk better in 59% of the tumors, including those >or=6.5 mm in height; spares the fovea better in 69% of the tumors, including those >or=5.5 mm; and spares lens better in only 30% of the tumors, with no distinction in size. Tumor location was not taken into account for this study, which could explain the variations in smaller tumors. For larger tumors, gamma knife will protect most organs at risk more effectively. This study shows how a tumor's parameters can be used in selecting treatment modality.

  3. SU-E-T-453: Optimization of Dose Gradient for Gamma Knife Radiosurgery.

    PubMed

    Sheth, N; Chen, Y; Yang, J

    2012-06-01

    The goals of stereotactic radiosurgery (SRS) are the ablation of target tissue and sparing of critical normal tissue. We develop tools to aid in the selection of collimation and prescription (Rx) isodose line to optimize the dose gradient for single isocenter intracranial stereotactic radiosurgery (SRS) with GammaKnife 4C utilizing the updated physics data in GammaPlan v10.1. Single isocenter intracranial SRS plans were created to treat the center of a solid water anthropomorphism head phantom for each GammaKnife collimator (4 mm, 8 mm, 14 mm, and 18 mm). The dose gradient, defined as the difference of effective radii of spheres equal to half and full Rx volumes, and Rx treatment volume was analyzed for isodoses from 99% to 20% of Rx. The dosimetric data on Rx volume and dose gradient vs. Rx isodose for each collimator was compiled into an easy to read nomogram as well as plotted graphically. The 4, 8, 14, and 18 mm collimators have the sharpest dose gradient at the 64%, 70%, 76%, and 77% Rx isodose lines, respectively. This corresponds to treating 4.77 mm, 8.86 mm, 14.78 mm, and 18.77 mm diameter targets with dose gradients radii of 1.06 mm, 1.63 mm, 2.54 mm, and 3.17 mm, respectively. We analyzed the dosimetric data for the most recent version of GammaPlan treatment planning software to develop tools that when applied clinically will aid in the selection of a collimator and Rx isodose line for optimal dose gradient and target coverage for single isocenter intracranial SRS with GammaKnife 4C. © 2012 American Association of Physicists in Medicine.

  4. Gamma Knife radiosurgery for glomus jugulare tumors: a single-center series of 75 cases.

    PubMed

    Ibrahim, Ramez; Ammori, Mohannad B; Yianni, John; Grainger, Alison; Rowe, Jeremy; Radatz, Matthias

    2017-05-01

    OBJECTIVE Glomus jugulare tumors are rare indolent tumors that frequently involve the lower cranial nerves (CNs). Complete resection can be difficult and associated with lower CN injury. Gamma Knife radiosurgery (GKRS) has established its role as a noninvasive alternative treatment option for these often formidable lesions. The authors aimed to review their experience at the National Centre for Stereotactic Radiosurgery, Sheffield, United Kingdom, specifically the long-term tumor control rate and complications of GKRS for these lesions. METHODS Clinical and radiological data were retrospectively reviewed for patients treated between March 1994 and December 2010. Data were available for 75 patients harboring 76 tumors. The tumors in 3 patients were treated in 2 stages. Familial and/or hereditary history was noted in 12 patients, 2 of whom had catecholamine-secreting and/or active tumors. Gamma Knife radiosurgery was the primary treatment modality in 47 patients (63%). The median age at the time of treatment was 55 years. The median tumor volume was 7 cm 3 , and the median radiosurgical dose to the tumor margin was 18 Gy (range 12-25 Gy). The median duration of radiological follow-up was 51.5 months (range 12-230 months), and the median clinical follow-up was 38.5 months (range 6-223 months). RESULTS The overall tumor control rate was 93.4% with low CN morbidity. Improvement of preexisting deficits was noted in 15 patients (20%). A stationary clinical course and no progression of symptoms were noted in 48 patients (64%). Twelve patients (16%) had new symptoms or progression of their preexisting symptoms. The Kaplan-Meier actuarial tumor control rate was 92.2% at 5 years and 86.3% at 10 years. CONCLUSIONS Gamma Knife radiosurgery offers a risk-versus-benefit treatment option with very low CN morbidity and stable long-term results.

  5. Completion of Gamma Knife radiosurgery for AVM treatment after unplanned interruption-technical note.

    PubMed

    Raman, Hari S; Santanam, Lakshmi; Vellimana, Ananth K; Drzymala, Robert E; Tsien, Christina I; Zipfel, Gregory J

    2018-02-17

    Gamma Knife radiosurgery is an established technique for non-urgent treatment of various intracranial pathologies. Intra-procedural dislodgement of the stereotactic frame is an uncommon occurrence that could lead to abortion of ongoing treatment and necessitate more invasive treatment strategies. In this case report, we describe a novel method for resumption of Gamma Knife treatment after an unplanned intra-procedural interruption. The case example involves a radiosurgical treatment of a Spetzler-Martin grade I arteriovenous malformation. Our technique involves integration of scans and coordinate systems from two imaging sessions using the composite isodose line to resolve translational differences, thereby limiting delivery of remaining shots to the untreated region of the lesion. MRI follow-up at 13 months showed a reduction in the nidus size with no evidence of any radiation injury to the surrounding brain parenchyma. We believe this technique will allow care teams to effectively salvage interrupted Gamma Knife procedures and reduce progression to more invasive treatment options.

  6. Multistage stereotactic radiosurgery for large cerebral arteriovenous malformations using the Gamma Knife platform.

    PubMed

    Ding, Chuxiong; Hrycushko, Brian; Whitworth, Louis; Li, Xiang; Nedzi, Lucien; Weprin, Bradley; Abdulrahman, Ramzi; Welch, Babu; Jiang, Steve B; Wardak, Zabi; Timmerman, Robert D

    2017-10-01

    Radiosurgery is an established technique to treat cerebral arteriovenous malformations (AVMs). Obliteration of larger AVMs (> 10-15 cm 3 or diameter > 3 cm) in a single session is challenging with current radiosurgery platforms due to toxicity. We present a novel technique of multistage stereotactic radiosurgery (SRS) for large intracranial arteriovenous malformations (AVM) using the Gamma Knife system. Eighteen patients with large (> 10-15 cm 3 or diameter > 3 cm) AVMs, which were previously treated using a staged SRS technique on the Cyberknife platform, were retrospectively selected for this study. The AVMs were contoured and divided into 3-8 subtargets to be treated sequentially in a staged approach at half to 4 week intervals. The prescription dose ranged from 15 Gy to 20 Gy, depending on the subtarget number, volume, and location. Gamma Knife plans using multiple collimator settings were generated and optimized. The coordinates of each shot from the initial plan covering the total AVM target were extracted based on their relative positions within the frame system. The shots were regrouped based on their location with respect to the subtarget contours to generate subplans for each stage. The delivery time of each shot for a subtarget was decay corrected with 60 Co for staging the treatment course to generate the same dose distribution as that planned for the total AVM target. Conformality indices and dose-volume analysis were performed to evaluate treatment plans. With the shot redistribution technique, the composite dose for the multistaged treatment of multiple subtargets is equivalent to the initial plan for total AVM target. Gamma Knife plans resulted in an average PTV coverage of 96.3 ± 0.9% and a PITV of 1.23 ± 0.1. The resulting Conformality indices, V 12Gy and R 50 dose spillage values were 0.76 ± 0.05, 3.4 ± 1.8, and 3.1 ± 0.5 respectively. The Gamma Knife system can deliver a multistaged conformal dose to treat large AVMs when correcting for

  7. Gamma Knife radiosurgery for the management of nonfunctioning pituitary adenomas: a multicenter study.

    PubMed

    Sheehan, Jason P; Starke, Robert M; Mathieu, David; Young, Byron; Sneed, Penny K; Chiang, Veronica L; Lee, John Y K; Kano, Hideyuki; Park, Kyung-Jae; Niranjan, Ajay; Kondziolka, Douglas; Barnett, Gene H; Rush, Stephen; Golfinos, John G; Lunsford, L Dade

    2013-08-01

    Pituitary adenomas are fairly common intracranial neoplasms, and nonfunctioning ones constitute a large subgroup of these adenomas. Complete resection is often difficult and may pose undue risk to neurological and endocrine function. Stereotactic radiosurgery has come to play an important role in the management of patients with nonfunctioning pituitary adenomas. This study examines the outcomes after radiosurgery in a large, multicenter patient population. Under the auspices of the North American Gamma Knife Consortium, 9 Gamma Knife surgery (GKS) centers retrospectively combined their outcome data obtained in 512 patients with nonfunctional pituitary adenomas. Prior resection was performed in 479 patients (93.6%) and prior fractionated external-beam radiotherapy was performed in 34 patients (6.6%). The median age at the time of radiosurgery was 53 years. Fifty-eight percent of patients had some degree of hypopituitarism prior to radiosurgery. Patients received a median dose of 16 Gy to the tumor margin. The median follow-up was 36 months (range 1-223 months). Overall tumor control was achieved in 93.4% of patients at last follow-up; actuarial tumor control was 98%, 95%, 91%, and 85% at 3, 5, 8, and 10 years postradiosurgery, respectively. Smaller adenoma volume (OR 1.08 [95% CI 1.02-1.13], p = 0.006) and absence of suprasellar extension (OR 2.10 [95% CI 0.96-4.61], p = 0.064) were associated with progression-free tumor survival. New or worsened hypopituitarism after radiosurgery was noted in 21% of patients, with thyroid and cortisol deficiencies reported as the most common postradiosurgery endocrinopathies. History of prior radiation therapy and greater tumor margin doses were predictive of new or worsening endocrinopathy after GKS. New or progressive cranial nerve deficits were noted in 9% of patients; 6.6% had worsening or new onset optic nerve dysfunction. In multivariate analysis, decreasing age, increasing volume, history of prior radiation therapy, and

  8. Worldwide variance in the potential utilization of Gamma Knife radiosurgery.

    PubMed

    Hamilton, Travis; Dade Lunsford, L

    2016-12-01

    OBJECTIVE The role of Gamma Knife radiosurgery (GKRS) has expanded worldwide during the past 3 decades. The authors sought to evaluate whether experienced users vary in their estimate of its potential use. METHODS Sixty-six current Gamma Knife users from 24 countries responded to an electronic survey. They estimated the potential role of GKRS for benign and malignant tumors, vascular malformations, and functional disorders. These estimates were compared with published disease epidemiological statistics and the 2014 use reports provided by the Leksell Gamma Knife Society (16,750 cases). RESULTS Respondents reported no significant variation in the estimated use in many conditions for which GKRS is performed: meningiomas, vestibular schwannomas, and arteriovenous malformations. Significant variance in the estimated use of GKRS was noted for pituitary tumors, craniopharyngiomas, and cavernous malformations. For many current indications, the authors found significant variance in GKRS users based in the Americas, Europe, and Asia. Experts estimated that GKRS was used in only 8.5% of the 196,000 eligible cases in 2014. CONCLUSIONS Although there was a general worldwide consensus regarding many major indications for GKRS, significant variability was noted for several more controversial roles. This expert opinion survey also suggested that GKRS is significantly underutilized for many current diagnoses, especially in the Americas. Future studies should be conducted to investigate health care barriers to GKRS for many patients.

  9. Stereotactic radiosurgery XX: ocular neuromyotonia in association with gamma knife radiosurgery

    PubMed Central

    McQuillan, Joe; Plowman, P Nicholas; MacDougall, Niall; Blackburn, Philip; Sabin, H Ian; Ali, Nadeem; Drake, William M

    2015-01-01

    Summary We report three patients who developed symptoms and signs of ocular neuromyotonia (ONM) 3–6 months after receiving gamma knife radiosurgery (GKS) for functioning pituitary tumours. All three patients were complex, requiring multi-modality therapy and all had received prior external irradiation to the sellar region. Although direct causality cannot be attributed, the timing of the development of the symptoms would suggest that the GKS played a contributory role in the development of this rare problem, which we suggest clinicians should be aware of as a potential complication. Learning points GKS can cause ONM, presenting as intermittent diplopia.ONM can occur quite rapidly after treatment with GKS.Treatment with carbamazepine is effective and improve patient's quality of life. PMID:26294961

  10. Emerging Indications for Fractionated Gamma Knife Radiosurgery.

    PubMed

    McTyre, Emory; Helis, Corbin A; Farris, Michael; Wilkins, Lisa; Sloan, Darrell; Hinson, William H; Bourland, J Daniel; Dezarn, William A; Munley, Michael T; Watabe, Kounosuke; Xing, Fei; Laxton, Adrian W; Tatter, Stephen B; Chan, Michael D

    2017-02-01

    Gamma Knife radiosurgery (GKRS) allows for the treatment of intracranial tumors with a high degree of dose conformality and precision. There are, however, certain situations wherein the dose conformality of GKRS is desired, but single session treatment is contraindicated. In these situations, a traditional pin-based GKRS head frame cannot be used, as it precludes fractionated treatment. To report our experience in treating patients with fractionated GKRS using a relocatable, noninvasive immobilization system. Patients were considered candidates for fractionated GKRS if they had one or more of the following indications: a benign tumor >10 cc in volume or abutting the optic pathway, a vestibular schwannoma with the intent of hearing preservation, or a tumor previously irradiated with single fraction GKRS. The immobilization device used for all patients was the Extend system (Leksell Gamma Knife Perfexion, Elekta, Kungstensgatan, Stockholm). We identified 34 patients treated with fractionated GKRS between August 2013 and February 2015. There were a total of 37 tumors treated including 15 meningiomas, 11 pituitary adenomas, 6 brain metastases, 4 vestibular schwannomas, and 1 hemangioma. At last follow-up, all 21 patients treated for perioptic tumors had stable or improved vision and all 4 patients treated for vestibular schwannoma maintained serviceable hearing. No severe adverse events were reported. Fractionated GKRS was well-tolerated in the treatment of large meningiomas, perioptic tumors, vestibular schwannomas with intent of hearing preservation, and in reirradiation of previously treated tumors.

  11. Emerging Indications for Fractionated Gamma Knife Radiosurgery

    PubMed Central

    McTyre, Emory; Helis, Corbin A.; Farris, Michael; Wilkins, Lisa; Sloan, Darrell; Hinson, William H.; Bourland, J. Daniel; Dezarn, William. A.; Munley, Michael T.; Watabe, Kounosuke; Xing, Fei; Laxton, Adrian W.; Tatter, Stephen B.; Chan, Michael D.

    2016-01-01

    BACKGROUND Gamma Knife radiosurgery (GKRS) allows for the treatment of intracranial tumors with a high degree of dose conformality and precision. There are, however, certain situations wherein the dose conformality of GKRS is desired, but single session treatment is contraindicated. In these situations, a traditional pin-based GKRS head frame cannot be used, as it precludes fractionated treatment. OBJECTIVE To report our experience in treating patients with fractionated GKRS using a relocatable, noninvasive immobilization system. METHODS Patients were considered candidates for fractionated GKRS if they had one or more of the following indications: a benign tumor >10 cc in volume or abutting the optic pathway, a vestibular schwannoma with the intent of hearing preservation, or a tumor previously irradiated with single fraction GKRS. The immobilization device used for all patients was the Extend system (Leksell Gamma Knife Perfexion, Elekta, Kungstensgatan, Stockholm). RESULTS We identified 34 patients treated with fractionated GKRS between August 2013 and February 2015. There were a total of 37 tumors treated including 15 meningiomas, 11 pituitary adenomas, 6 brain metastases, 4 vestibular schwannomas, and 1 hemangioma. At last follow-up, all 21 patients treated for perioptic tumors had stable or improved vision and all 4 patients treated for vestibular schwannoma maintained serviceable hearing. No severe adverse events were reported. CONCLUSION Fractionated GKRS was well-tolerated in the treatment of large meningiomas, perioptic tumors, vestibular schwannomas with intent of hearing preservation, and in reirradiation of previously treated tumors. PMID:28536486

  12. Radiological aspects of gamma knife radiosurgery for arteriovenous malformations and other non-tumoural disorders of the brain.

    PubMed

    Guo, W Y

    1993-01-01

    The aims of the thesis were to investigate stereotaxic procedures in radiosurgery for cerebral arteriovenous malformations (AVMs) and radiation effects of single session high-dose irradiation delivered by gamma knife on the human brain. Investigation of gamma knife radiosurgery in 1,464 patients constitutes the data base of this thesis. High quality stereotaxic angiography is the gold standard targeting imaging in radiosurgery for cerebral AVMs, particularly for small AVMs or residual AVMs after other treatments. For medium and large size AVMs, stereotaxic MR techniques can improve targeting precision and decrease irradiation volume as compared to stereotaxic angiography in selected cases provided that proper pulse sequences are used. Combined treatments, where embolization precedes radiosurgery, can improve amenability of the treatment for large AVMs. This is on condition that the partially embolized nidi are well delineated and the volume of the residual nidi has been decreased to a level where an optimum irradiation can be safely prescribed. Radiologically, adverse radiation effects (ARE) of gamma knife radiosurgery for cerebral AVMs are observed in 16% (131/816) of the patients. The ARE are observed as a focal low attenuation on CT or as a focal high signal on MR image without enhancement in 47% (61/131), and as a peripheral or homogeneous enhancing lesion in 48% (63/131). MR imaging is more sensitive than CT in detecting the ARE. 91% of the ARE are observed within 18 months after radiosurgery and 89% are seen to regress within 18 months. Clinically, symptomatic ARE are only observed in 6% (51/816) and only in half of them, i.e. 3%, are the symptoms permanent. The risk of ARE in radiosurgery for venous angiomas is higher as compared to AVMs. Other mechanisms have probably been employed. In gamma capsulotomy, the necrotic lesions and reaction volumes created by using multiple isocentres of 4 mm collimators are less predictable as compared to that by single

  13. WE-G-BRA-08: Failure Modes and Effects Analysis (FMEA) for Gamma Knife Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Y; Bhatnagar, J; Bednarz, G

    2015-06-15

    Purpose: To perform a failure modes and effects analysis (FMEA) study for Gamma Knife (GK) radiosurgery processes at our institution based on our experience with the treatment of more than 13,000 patients. Methods: A team consisting of medical physicists, nurses, radiation oncologists, neurosurgeons at the University of Pittsburgh Medical Center and an external physicist expert was formed for the FMEA study. A process tree and a failure mode table were created for the GK procedures using the Leksell GK Perfexion and 4C units. Three scores for the probability of occurrence (O), the severity (S), and the probability of no detectionmore » (D) for failure modes were assigned to each failure mode by each professional on a scale from 1 to 10. The risk priority number (RPN) for each failure mode was then calculated (RPN = OxSxD) as the average scores from all data sets collected. Results: The established process tree for GK radiosurgery consists of 10 sub-processes and 53 steps, including a sub-process for frame placement and 11 steps that are directly related to the frame-based nature of the GK radiosurgery. Out of the 86 failure modes identified, 40 failure modes are GK specific, caused by the potential for inappropriate use of the radiosurgery head frame, the imaging fiducial boxes, the GK helmets and plugs, and the GammaPlan treatment planning system. The other 46 failure modes are associated with the registration, imaging, image transfer, contouring processes that are common for all radiation therapy techniques. The failure modes with the highest hazard scores are related to imperfect frame adaptor attachment, bad fiducial box assembly, overlooked target areas, inaccurate previous treatment information and excessive patient movement during MRI scan. Conclusion: The implementation of the FMEA approach for Gamma Knife radiosurgery enabled deeper understanding of the overall process among all professionals involved in the care of the patient and helped identify

  14. P11.10 Role of hydroxyurea as an adjuvant treatment after gamma knife radiosurgery for atypical (WHO grade II) meningiomas

    PubMed Central

    Abdel Karim, K.; El Shehaby, A.; Emad, R.; Reda, W.; El Mahdy, M.; Ghali, R.; Nabeel, A.

    2016-01-01

    Abstract Objective: The use of gamma knife radiosurgery in the treatment of atypical (WHO grade II) meningiomas has been reported in the past with highly variable degrees of success. The use of hydroxyurea as a radiation sensitizer as well as salvage chemotherapy in cancer patients is well established and was also used for treatment of recurrent and malignant meningiomas. In this study we investigated the effect of hydroxyurea administration after gamma knife radiosurgery for atypical (grade II) meningiomas on local tumor control and patient survival. Patients and methods: Between November 2008 and April 2014, thirty-five patients with pathologically proven atypical meningiomas were treated by gamma knife radiosurgery. We excluded patients who had received previous external beam radiotherapy. Twenty-three patients were given hydroxyurea after gamma knife treatment. The rest of the patients refused to take the treatment or were incompliant (were not included in the study). Of these 23, nineteen patients harboring 20 tumors were available for radiological and clinical follow up for a minimum of 2 years. Four patients were lost from follow up. Twenty tumors underwent 26 gamma knife procedures. Five tumors underwent staged treatment. The tumor volume was 0.6–38.3 cc (median 12.7 cc). The prescription dose/session ranged from 10 to 16 Gy (mean 14 Gy). The patients received a course of hydroxyurea (1000 mg/day) for one year after gamma knife treatment. The mean follow up period was 43 months (14–76 months). Results: Tumor control was achieved in 18 out of 20 tumors where 15 tumors shrank and 3 tumors remained stable with a tumor control rate of 90%. Tumor progression occurred in 2 patients (at 14 and 15 months). Transient edema was observed with 6 tumors which was temporary, and no G3 or G4 myelosuppression were recorded. Two patients died from progression of other tumors not included in the study after 3 and 6 years. Distant tumor progression (in another

  15. Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate.

    PubMed

    Linskey, M E

    2000-12-01

    By definition, the term "radiosurgery" refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed "stereotactic radiotherapy." There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image-targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS "halo effect." It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the

  16. Stereotactic radiosurgery versus stereotactic radiotherapy for patients with vestibular schwannoma: a Leksell Gamma Knife Society 2000 debate.

    PubMed

    Linskey, Mark E

    2013-12-01

    By definition, the term "radiosurgery" refers to the delivery of a therapeutic radiation dose in a single fraction, not simply the use of stereotaxy. Multiple-fraction delivery is better termed "stereotactic radiotherapy." There are compelling radiobiological principles supporting the biological superiority of single-fraction radiation for achieving an optimal therapeutic response for the slowly proliferating, late-responding, tissue of a schwannoma. It is axiomatic that complication avoidance requires precise three-dimensional conformality between treatment and tumor volumes. This degree of conformality can only be achieved through complex multiisocenter planning. Alternative radiosurgery devices are generally limited to delivering one to four isocenters in a single treatment session. Although they can reproduce dose plans similar in conformality to early gamma knife dose plans by using a similar number of isocenters, they cannot reproduce the conformality of modern gamma knife plans based on magnetic resonance image--targeted localization and five to 30 isocenters. A disturbing trend is developing in which institutions without nongamma knife radiosurgery (GKS) centers are championing and/or shifting to hypofractionated stereotactic radiotherapy for vestibular schwannomas. This trend appears to be driven by a desire to reduce complication rates to compete with modern GKS results by using complex multiisocenter planning. Aggressive advertising and marketing from some of these centers even paradoxically suggests biological superiority of hypofractionation approaches over single-dose radiosurgery for vestibular schwannomas. At the same time these centers continue to use the term radiosurgery to describe their hypofractionated radiotherapy approach in an apparent effort to benefit from a GKS "halo effect." It must be reemphasized that as neurosurgeons our primary duty is to achieve permanent tumor control for our patients and not to eliminate complications at the

  17. Radiosurgery with the world's first fully robotized Leksell Gamma Knife PerfeXion in clinical use: a 200-patient prospective, randomized, controlled comparison with the Gamma Knife 4C.

    PubMed

    Régis, Jean; Tamura, Manabu; Guillot, Cécile; Yomo, Shoji; Muraciolle, Xavier; Nagaje, Mariko; Arka, Yasser; Porcheron, Denis

    2009-02-01

    The world's first Leksell Gamma Knife PerfeXion (Elekta Instrument AB, Stockholm, Sweden) for radiosurgery of the head and neck became operational at Timone University Hospital in Marseille on July 10, 2006. To allow strict evaluation of the capabilities, advantages, disadvantages, and limitations of this new technology, patients were enrolled in a prospective, randomized trial. In 66 working days, between July 10 and December 20, 2006, 363 patients were treated by gamma knife surgery at Timone University Hospital, Marseille. Of these patients, 200 were eligible for the comparative prospective study (inclusion criteria were informed consent obtained, tumor or vascular indication, and no previous radiosurgery or radiotherapy). In accordance with the blinded randomization process, 100 patients were treated with the Leksell Gamma Knife 4C (Elekta Instrument AB) and Gamma Knife 100 (Elekta Instrument AB) with the Leksell Gamma Knife PerfeXion. Dose planning parameters, dosimetry measurements on the patient's body, workflow, patient comfort, quality assurance procedure, and a series of other treatment-related parameters were systematically and prospectively evaluated in both arms of the trial. No technical failure of the treatment procedure was encountered. The new dose-planning system led to the use of composite shots in 39.4% of the patients. The median number of different collimator sizes used was larger with the PerfeXion than with the 4C (2 and 1, respectively). The mean number of isocenters used was lower (10.67 and 13.08, respectively). The median total treatment time was significantly shorter with the PerfeXion (40 and 60 minutes, respectively), but there was no significant difference in the median radiation time (34.02 and 33.40 minutes, respectively). The procedure was performed using only a single run in 98.99% of the PerfeXion cases and in 42% of the 4C cases. Collision risk on the 4C forced us to change the frame gamma angle for at least 1 shot in 24% of

  18. Hypertrophic olivary degeneration following surgical resection or gamma knife radiosurgery of brainstem cavernous malformations: an 11-case series and a review of literature.

    PubMed

    Yun, Jung-Ho; Ahn, Jae Sung; Park, Jung Cheol; Kwon, Do Hoon; Kwun, Byung Duk; Kim, Chang Jin

    2013-03-01

    We describe 11 patients with hypertrophic olivary degeneration (HOD) after surgical resection or gamma knife radiosurgery for brainstem cavernous malformations. In addition, we statistically analyzed the predicting factors associated with the development of HOD. From January 2001 to May 2011, a total of 73 patients (30 in the surgical group and 43 in the radiosurgery group) with brainstem cavernous malformations were treated in our institute. Of them, 11 patients (incidence: 15 %) developed HOD with high signal intensity on T2-weighted MRI during follow-up. The predicting factors (location, size, age, and treatment method) associated with the development of HOD were statistically analyzed. Among the 11 HOD patients, seven patients received surgical resection and four patients received gamma knife radiosurgery. Six patients had bilateral HOD and the remaining five patients had unilateral HOD. Overall HOD-associated symptoms presented in four patients, including three palatal tremors and one ataxia. In all four patients with symptoms, these symptoms disappeared incompletely within the clinical follow-up period. The size of the cavernous malformation, age of patient, and treatment methods were not significantly correlated with the development of HOD. A significantly higher incidence of HOD was associated with midbrain cavernous malformations than with pontine or medulla cavernous malformations. HOD should be recognized as a non-infrequent complication of surgical resection or gamma knife radiosurgery within the brainstem, especially for midbrain cavernous malformations. In addition, to the best of our knowledge, this is the first report on HOD development after radiosurgery.

  19. Gamma Knife treatment of low-grade gliomas in children.

    PubMed

    Ekşi, Murat Şakir; Yılmaz, Baran; Akakın, Akın; Toktaş, Zafer Orkun; Kaur, Ahmet Cemil; Demir, Mustafa Kemal; Kılıç, Türker

    2015-11-01

    Low-grade gliomas have good overall survival rates in pediatric patients compared to adults. There are some case series that reported the effectiveness and safety of Gamma Knife radiosurgery, yet they are limited in number of patients. We aimed to review the relevant literature for pediatric low-grade glial tumors treated with stereotactic radiosurgery, specifically Gamma Knife radiosurgery, and to present an exemplary case. A 6-year-old boy was admitted to clinic due to head trauma. He was alert, cooperative, and had no obvious motor or sensorial deficit. A head CT scan depicted a hypodense zone at the right caudate nucleus. The brain magnetic resonance imaging (MRI) depicted a mass lesion at the same location. A stereotactic biopsy was performed. Histopathological diagnosis was low-grade astrocytoma (grade II, World Health Organization (WHO) classification, 2007). Gamma Knife radiosurgery was applied to the tumor bed. Tumor volume was 21.85 cm(3). Fourteen gray was given to 50% isodose segment of the lesion (maximal dose of 28 Gy). The tumor has disappeared totally in 4 months, and the patient was tumor-free 21 months after the initial treatment. The presented literature review represents mostly single-center experiences with different patient and treatment characteristics. Accordingly, a mean/median margin dose of 11.3-15 Gy with Gamma Knife radiosurgery (GKRS) is successful in treatment of pediatric and adult low-grade glial tumor patients. However, prospective studies with a large cohort of pediatric patients should be conducted to make a more comprehensive conclusion for effectiveness and safety of GKRS in pediatric low-grade glial tumors.

  20. Gamma Knife Radiosurgery for Skull Base Meningiomas: Long-Term Radiologic and Clinical Outcome

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Han, Jung Ho; Kim, Dong Gyu; Chung, Hyun-Tai

    2008-12-01

    Purpose: To analyze the long-term outcomes in patients with skull base meningiomas (SBMNGs) treated with Gamma Knife radiosurgery (GKRS). Methods and Materials: Of the 98 consecutive patients with SBMNGs treated with GKRS between 1998 and 2002, 63 were followed up for more than 48 months. The mean ({+-}SD) age of the patients was 50 {+-} 12 years, the mean tumor volume was 6.5 cm{sup 3} (range, 0.5-18.4 cm{sup 3}), the mean marginal dose was 12.6 Gy (range, 7.0-20.0 Gy), and the mean follow-up duration was 77 {+-} 18 months. The mean number of shots was 13.7 {+-} 3.8. The tumormore » volume was decreased at the last follow-up in 28 patients (44.4%) and increased in 6 (9.6%). The actuarial tumor control rate was 90.2% at 5 years. No notable prognostic factor related to tumor control was identified. Ten patients (15.9%) with a cranial neuropathy showed unfavorable outcomes. The rate of improvement in patients with a cranial neuropathy was 45.1%. Age >70 years was likely correlated with an unfavorable outcome in patients with cranial neuropathy (odds ratio = 0.027; p = 0.025; 95% confidence interval 0.001-0.632). Cavernous sinus location was significantly associated with improvement of a cranial neuropathy (odds ratio = 7.314; p = 0.007; 95% confidence interval 1.707-31.34). Conclusions: Gamma Knife radiosurgery is an effective modality for the treatment of SBMNGs and provides favorable outcomes in patients with cranial neuropathy, even in the long-term follow-up period. However, radiosurgery for patients with no or only mild symptoms should be performed cautiously because neither complication rate is low enough to be negligible, especially in elderly patients. A cranial neuropathy by MNGs involving the cavernous sinus seems to have a higher chance of improvement after radiosurgery than other SBMNGs.« less

  1. Gamma knife radiosurgery for typical trigeminal neuralgia: An institutional review of 108 patients

    PubMed Central

    Elaimy, Ameer L.; Lamm, Andrew F.; Demakas, John J.; Mackay, Alexander R.; Lamoreaux, Wayne T.; Fairbanks, Robert K.; Pfeffer, Robert D.; Cooke, Barton S.; Peressini, Benjamin J.; Lee, Christopher M.

    2013-01-01

    Background: In this study, we present the previously unreported pain relief outcomes of 108 patients treated at Gamma Knife of Spokane for typical trigeminal neuralgia (TN) between 2002 and 2011. Methods: Pain relief outcomes were measured using the Barrow Neurological Institute (BNI) pain intensity scale. In addition, the effects gender, age at treatment, pain laterality, previous surgical treatment, repeat Gamma Knife radiosurgery (GKRS), and maximum radiosurgery dose have on patient pain relief outcomes were retrospectively analyzed. Statistical analysis was performed using Andersen 95% confidence intervals, approximate confidence intervals for log hazard ratios, and multivariate Cox proportional hazard models. Results: All 108 patients included in this study were grouped into BNI class IV or V prior to GKRS. The median clinical follow-up time was determined to be 15 months. Following the first GKRS procedure, 71% of patients were grouped into BNI class I-IIIb (I = 31%; II = 3%; IIIa = 19%; IIIb = 18%) and the median duration of pain relief for those patients was determined to be 11.8 months. New facial numbness was reported in 19% of patients and new facial paresthesias were reported in 7% of patients after the first GKRS procedure. A total of 19 repeat procedures were performed on the 108 patients included in this study. Following the second GKRS procedure, 73% of patients were grouped into BNI class I-IIIb (I = 44%; II = 6%; IIIa = 17%, IIIb = 6%) and the median duration of pain relief for those patients was determined to be 4.9 months. For repeat procedures, new facial numbness was reported in 22% of patients and new facial paresthesias were reported in 6% of patients. Conclusions: GKRS is a safe and effective management approach for patients diagnosed with typical TN. However, further studies and supporting research is needed on the effects previous surgical treatment, number of radiosurgery procedures, and maximum radiosurgery dose have on GKRS clinical

  2. Shot sequencing based on biological equivalent dose considerations for multiple isocenter Gamma Knife radiosurgery.

    PubMed

    Ma, Lijun; Lee, Letitia; Barani, Igor; Hwang, Andrew; Fogh, Shannon; Nakamura, Jean; McDermott, Michael; Sneed, Penny; Larson, David A; Sahgal, Arjun

    2011-11-21

    Rapid delivery of multiple shots or isocenters is one of the hallmarks of Gamma Knife radiosurgery. In this study, we investigated whether the temporal order of shots delivered with Gamma Knife Perfexion would significantly influence the biological equivalent dose for complex multi-isocenter treatments. Twenty single-target cases were selected for analysis. For each case, 3D dose matrices of individual shots were extracted and single-fraction equivalent uniform dose (sEUD) values were determined for all possible shot delivery sequences, corresponding to different patterns of temporal dose delivery within the target. We found significant variations in the sEUD values among these sequences exceeding 15% for certain cases. However, the sequences for the actual treatment delivery were found to agree (<3%) and to correlate (R² = 0.98) excellently with the sequences yielding the maximum sEUD values for all studied cases. This result is applicable for both fast and slow growing tumors with α/β values of 2 to 20 according to the linear-quadratic model. In conclusion, despite large potential variations in different shot sequences for multi-isocenter Gamma Knife treatments, current clinical delivery sequences exhibited consistent biological target dosing that approached that maximally achievable for all studied cases.

  3. Shot sequencing based on biological equivalent dose considerations for multiple isocenter Gamma Knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Ma, Lijun; Lee, Letitia; Barani, Igor; Hwang, Andrew; Fogh, Shannon; Nakamura, Jean; McDermott, Michael; Sneed, Penny; Larson, David A.; Sahgal, Arjun

    2011-11-01

    Rapid delivery of multiple shots or isocenters is one of the hallmarks of Gamma Knife radiosurgery. In this study, we investigated whether the temporal order of shots delivered with Gamma Knife Perfexion would significantly influence the biological equivalent dose for complex multi-isocenter treatments. Twenty single-target cases were selected for analysis. For each case, 3D dose matrices of individual shots were extracted and single-fraction equivalent uniform dose (sEUD) values were determined for all possible shot delivery sequences, corresponding to different patterns of temporal dose delivery within the target. We found significant variations in the sEUD values among these sequences exceeding 15% for certain cases. However, the sequences for the actual treatment delivery were found to agree (<3%) and to correlate (R2 = 0.98) excellently with the sequences yielding the maximum sEUD values for all studied cases. This result is applicable for both fast and slow growing tumors with α/β values of 2 to 20 according to the linear-quadratic model. In conclusion, despite large potential variations in different shot sequences for multi-isocenter Gamma Knife treatments, current clinical delivery sequences exhibited consistent biological target dosing that approached that maximally achievable for all studied cases.

  4. Assessment of absorbed dose to thyroid, parotid and ovaries in patients undergoing Gamma Knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Hasanzadeh, H.; Sharafi, A.; Allah Verdi, M.; Nikoofar, A.

    2006-09-01

    Stereotactic radiosurgery was originally introduced by Lars Leksell in 1951. This treatment refers to the noninvasive destruction of an intracranial target localized stereotactically. The purpose of this study was to identify the dose delivered to the parotid, ovaries, testis and thyroid glands during the Gamma Knife radiosurgery procedure. A three-dimensional, anthropomorphic phantom was developed using natural human bone, paraffin and sodium chloride as the equivalent tissue. The phantom consisted of a thorax, head and neck and hip. In the natural places of the thyroid, parotid (bilateral sides) and ovaries (midline), some cavities were made to place TLDs. Three TLDs were inserted in a batch with 1 cm space between the TLDs and each batch was inserted into a single cavity. The final depth of TLDs was 3 cm from the surface for parotid and thyroid and was 15 cm for the ovaries. Similar batches were placed superficially on the phantom. The phantom was gamma irradiated using a Leksell model C Gamma Knife unit. Subsequently, the same batches were placed superficially over the thyroid, parotid, testis and ovaries in 30 patients (15 men and 15 women) who were undergoing radiosurgery treatment for brain tumours. The mean dosage for treating these patients was 14.48 ± 3.06 Gy (10.5-24 Gy) to a mean tumour volume of 12.30 ± 9.66 cc (0.27-42.4 cc) in the 50% isodose curve. There was no significant difference between the superficial and deep batches in the phantom studies (P-value < 0.05). The mean delivered doses to the parotid, thyroid, ovaries and testis in human subjects were 21.6 ± 15.1 cGy, 9.15 ± 3.89 cGy, 0.47 ± 0.3 cGy and 0.53 ± 0.31 cGy, respectively. The data can be used in making decisions for special clinical situations such as treating pregnant patients or young patients with benign lesions who need radiosurgery for eradication of brain tumours.

  5. Assessment of absorbed dose to thyroid, parotid and ovaries in patients undergoing Gamma Knife radiosurgery.

    PubMed

    Hasanzadeh, H; Sharafi, A; Allah Verdi, M; Nikoofar, A

    2006-09-07

    Stereotactic radiosurgery was originally introduced by Lars Leksell in 1951. This treatment refers to the noninvasive destruction of an intracranial target localized stereotactically. The purpose of this study was to identify the dose delivered to the parotid, ovaries, testis and thyroid glands during the Gamma Knife radiosurgery procedure. A three-dimensional, anthropomorphic phantom was developed using natural human bone, paraffin and sodium chloride as the equivalent tissue. The phantom consisted of a thorax, head and neck and hip. In the natural places of the thyroid, parotid (bilateral sides) and ovaries (midline), some cavities were made to place TLDs. Three TLDs were inserted in a batch with 1 cm space between the TLDs and each batch was inserted into a single cavity. The final depth of TLDs was 3 cm from the surface for parotid and thyroid and was 15 cm for the ovaries. Similar batches were placed superficially on the phantom. The phantom was gamma irradiated using a Leksell model C Gamma Knife unit. Subsequently, the same batches were placed superficially over the thyroid, parotid, testis and ovaries in 30 patients (15 men and 15 women) who were undergoing radiosurgery treatment for brain tumours. The mean dosage for treating these patients was 14.48 +/- 3.06 Gy (10.5-24 Gy) to a mean tumour volume of 12.30 +/- 9.66 cc (0.27-42.4 cc) in the 50% isodose curve. There was no significant difference between the superficial and deep batches in the phantom studies (P-value < 0.05). The mean delivered doses to the parotid, thyroid, ovaries and testis in human subjects were 21.6 +/- 15.1 cGy, 9.15 +/- 3.89 cGy, 0.47 +/- 0.3 cGy and 0.53 +/- 0.31 cGy, respectively. The data can be used in making decisions for special clinical situations such as treating pregnant patients or young patients with benign lesions who need radiosurgery for eradication of brain tumours.

  6. Gamma knife radiosurgery for symptomatic brainstem intra-axial cavernous malformations.

    PubMed

    Park, Seong-Hyun; Hwang, Sung-Kyoo

    2013-12-01

    The purpose of this study was to evaluate the efficacy and safety of gamma knife radiosurgery (GKRS) for the treatment of symptomatic brainstem intra-axial cavernous malformations (CMs) associated with high surgical morbidity. Twenty-one patients with symptomatic brainstem intra-axial CMs were treated by GKRS between 2005 and 2010. One patient was lost to follow-up. The median age of the patients was 39.5 years (range, 24-69 years). All patients had experienced 1 or more symptomatic hemorrhages before GKRS (range, 1-3). The median marginal radiation dose was 13 Gy, and the median volume of the malformation was 0.56 mL. The median follow-up period after radiosurgery was 32 months (range, 12-82 months; mean, 38.9 months). Before GKRS, 31 hemorrhages (1.55 per patient) were observed. The annual hemorrhage rate before GKRS was 39.5%, excluding the first hemorrhage. After GKRS, 1 hemorrhage (0.05 per patient) was identified. It occurred 6 months after radiosurgery. The patient showed complete recovery to a premorbid status with steroid medication. The annual hemorrhage rate after GKRS was 8.2% for the first 2 years. After the expected latency period, no hemorrhages were identified. One patient (5%) exhibited permanent paresthesia, which was a new neurologic symptom in absence of any hemorrhagic event, after the radiosurgery. GKRS seems to be relatively effective and safe for reducing the rebleeding rate of brainstem intra-axial CMs that have high surgical risk. Careful selection of a low marginal dose and an optimal radiosurgical technique are helpful to achieve good outcomes. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Dose verification to cochlea during gamma knife radiosurgery of acoustic schwannoma using MOSFET dosimeter.

    PubMed

    Sharma, Sunil D; Kumar, Rajesh; Akhilesh, Philomina; Pendse, Anil M; Deshpande, Sudesh; Misra, Basant K

    2012-01-01

    Dose verification to cochlea using metal oxide semiconductor field effect transistor (MOSFET) dosimeter using a specially designed multi slice head and neck phantom during the treatment of acoustic schwannoma by Gamma Knife radiosurgery unit. A multi slice polystyrene head phantom was designed and fabricated for measurement of dose to cochlea during the treatment of the acoustic schwannoma. The phantom has provision to position the MOSFET dosimeters at the desired location precisely. MOSFET dosimeters of 0.2 mm x 0.2 mm x 0.5 μm were used to measure the dose to the cochlea. CT scans of the phantom with MOSFETs in situ were taken along with Leksell frame. The treatment plans of five patients treated earlier for acoustic schwannoma were transferred to the phantom. Dose and coordinates of maximum dose point inside the cochlea were derived. The phantom along with the MOSFET dosimeters was irradiated to deliver the planned treatment and dose received by cochlea were measured. The treatment planning system (TPS) estimated and measured dose to the cochlea were in the range of 7.4 - 8.4 Gy and 7.1 - 8 Gy, respectively. The maximum variation between TPS calculated and measured dose to cochlea was 5%. The measured dose values were found in good agreement with the dose values calculated using the TPS. The MOSFET dosimeter can be a suitable choice for routine dose verification in the Gamma Knife radiosurgery.

  8. Gamma Knife radiosurgery for intracranial hemangioblastoma.

    PubMed

    Silva, Danilo; Grabowski, Mathew M; Juthani, Rupa; Sharma, Mayur; Angelov, Lilyana; Vogelbaum, Michael A; Chao, Samuel; Suh, John; Mohammadi, Alireza; Barnett, Gene H

    2016-09-01

    Gamma knife radiosurgery (GKRS) has become a treatment option for intracranial hemangioblastomas, especially in patients with poor clinical status and also high-risk surgical candidates. The objective of this study was to analyze clinical outcome and tumor control rates. Retrospective chart review revealed 12 patients with a total of 20 intracranial hemangioblastomas treated with GKRS from May 1998 until December 2014. Kaplan-Meier plots were used to calculate the actuarial local tumor control rates and rate of recurrence following GKRS. Univariate analysis, including log rank test and Wilcoxon test were used on the Kaplan-Meier plots to evaluate the predictors of tumor progression. Two-tailed p value of <0.05 was considered as significant. Median follow-up was 64months (2-184). Median tumor volume pre-GKRS was 946mm(3) (79-15970), while median tumor volume post-GKRS was 356mm(3) (30-5404). Complications were seen in two patients. Tumor control rates were 100% at 1year, 90% at 3years, and 85% at 5years, using the Kaplan-Meier method. There were no statistically significant univariate predictors of progression identified, although there was a trend towards successful tumor control in solid tumors (p=0.07). GKRS is an effective and safe option for treating intracranial hemangioblastoma with favorable tumor control rates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Gamma Knife radiosurgery for hemangioma of the cavernous sinus.

    PubMed

    Lee, Cheng-Chia; Sheehan, Jason P; Kano, Hideyuki; Akpinar, Berkcan; Martinez-Alvarez, Roberto; Martinez-Moreno, Nuria; Guo, Wan-Yuo; Lunsford, L Dade; Liu, Kang-Du

    2017-05-01

    OBJECTIVE Cavernous sinus hemangiomas (CSHs) are rare vascular tumors. A direct microsurgical approach usually results in massive hemorrhage and incomplete tumor resection. Although stereotactic radiosurgery (SRS) has emerged as a therapeutic alternative to microsurgery, outcome studies are few. Authors of the present study evaluated the role of SRS for CSH. METHODS An international multicenter study was conducted to review outcome data in 31 patients with CSH. Eleven patients had initial microsurgery before SRS, and the other 20 patients (64.5%) underwent Gamma Knife SRS as the primary management for their CSH. Median age at the time of radiosurgery was 47 years, and 77.4% of patients had cranial nerve dysfunction before SRS. Patients received a median tumor margin dose of 12.6 Gy (range 12-19 Gy) at a median isodose of 55%. RESULTS Tumor regression was confirmed by imaging in all 31 patients, and all patients had greater than 50% reduction in tumor volume at 6 months post-SRS. No patient had delayed tumor growth, new cranial neuropathy, visual function deterioration, adverse radiation effects, or hypopituitarism after SRS. Twenty-four patients had presented with cranial nerve disorders before SRS, and 6 (25%) of them had gradual improvement. Four (66.7%) of the 6 patients with orbital symptoms had symptomatic relief at the last follow-up. CONCLUSIONS Stereotactic radiosurgery was effective in reducing the volume of CSH and attaining long-term tumor control in all patients at a median of 40 months. The authors' experience suggests that SRS is a reasonable primary and adjuvant treatment modality for patients in whom a CSH is diagnosed.

  10. Long-term outcomes of Gamma Knife radiosurgery in patients with vestibular schwannomas.

    PubMed

    Murphy, Erin S; Barnett, Gene H; Vogelbaum, Michael A; Neyman, Gennady; Stevens, Glen H J; Cohen, Bruce H; Elson, Paul; Vassil, Andrew D; Suh, John H

    2011-02-01

    The authors sought to determine the long-term tumor control and side effects of Gamma Knife radiosurgery (GKRS) in patients with vestibular schwannomas (VS). One hundred seventeen patients with VS underwent GKRS between January 1997 and February 2003. At the time of analysis, at least 5 years had passed since GKRS in all patients. The mean patient age was 60.9 years. The mean maximal tumor diameter was 1.77 ± 0.71 cm. The mean tumor volume was 1.95 ± 2.42 ml. Eighty-two percent of lesions received 1300 cGy and 14% received 1200 cGy. The median dose homogeneity ratio was 1.97 and the median dose conformality ratio was 1.78. Follow-up included MR imaging or CT scanning approximately every 6-12 months. Rates of progression to surgery were calculated using the Kaplan-Meier method. Of the 117 patients in whom data were analyzed, 103 had follow-up MR or CT images and 14 patients were lost to follow-up. Fifty-three percent of patients had stable tumors and 37.9% had a radiographically documented response. Imaging-documented tumor progression was present in 8 patients (7.8%), but in 3 of these the lesion eventually stabilized. Only 5 patients required a neurosurgical intervention. The estimated 1-, 3-, and 5-year rates of progression to surgery were 1, 4.6, and 8.9%, respectively. One patient (1%) developed trigeminal neuropathy, 4 patients (5%) developed permanent facial neuropathy, 3 patients (4%) reported vertigo, and 7 patients (18%) had new gait imbalance following GKRS. Gamma Knife radiosurgery results in excellent local control rates with minimal toxicity for patients with VS. The authors recommend standardized follow-up to gain a better understanding of the long-term effects of GKRS.

  11. Gamma Knife radiosurgery for the treatment of intracranial dural arteriovenous fistulas

    PubMed Central

    Dmytriw, Adam A; Schwartz, Michael L; Cusimano, Michael D; Mendes Pereira, Vitor; Krings, Timo; Tymianski, Michael; Radovanovic, Ivan

    2016-01-01

    Background Intracranial dural arteriovenous fistulae (DAVF) may present a treatment challenge. Endovascular embolization is in most cases the first line of treatment but does not always achieve cure. Gamma Knife (GK) radiosurgery represents an alternative treatment option, and the purpose of this study was to further evaluate its utility. Methods We reviewed all cases of DAVF treated between 2009 and 2016 at our institution with GK radiosurgery independently, or following failed/refused endovascular or surgical management. Patients’ clinical files, radiological images, catheter angiograms, and surgical DAVF disconnection reports were retrospectively reviewed. Results Sixteen DAVF (14 patients) treated by GK radiosurgery were identified. Eleven fistulae were aggressive and five were benign. Marginal doses ranged from 15 to 25 Gy. Target volumes ranged from 0.04 to 4.47 cm3. In all symptomatic patients, GK treatment resulted in symptom palliation. In 13/15 lesions, cure of symptoms (86.0%) was reported. One lesion was asymptomatic. Angiographic cure was achieved in eight cases (50%), small residual DAVF occurred in four, and four were unchanged. One patient developed headache that resolved at one year. No hemorrhage occurred during the follow-up period. There was no significant association between Borden type and cure rate. Prior failed endovascular treatment and small target volume were associated with lower rates of cure. Conclusions Stereotactic radiosurgery is viable treatment for DAVF. It is very effective in palliating symptoms as a de novo approach or adjunctive to endovascular therapy. In our experience it is only somewhat effective in achieving complete angiographic cure. PMID:28156167

  12. Evaluation of fractionated radiotherapy and gamma knife radiosurgery in cavernous sinus meningiomas: treatment strategy.

    PubMed

    Metellus, Philipe; Regis, Jean; Muracciole, Xavier; Fuentes, Stephane; Dufour, Henry; Nanni, Isabelle; Chinot, Oliver; Martin, Pierre-Marie; Grisoli, Francois

    2005-11-01

    To investigate the respective role of fractionated radiotherapy (FR) and gamma knife stereotactic (GKS) radiosurgery in cavernous sinus meningioma (CSM) treatment. The authors report the long-term follow-up of two populations of patients harboring CSMs treated either by FR (Group I, 38 patients) or GKS radiosurgery (Group II, 36 patients). There were 31 females with a mean age of 53 years in Group I and 29 females with a mean age of 51.2 years in Group II. In 20 patients (Group I) and 13 patients (Group II), FR and GKS radiosurgery were performed as an adjuvant treatment. In 18 patients (Group I) and in 23 patients (Group II), FR and GKS radiosurgery were performed as first line treatment. In our early experience with GKS radiosurgery (1992, date of gamma knife availability in the department), patients with tumors greater than 3 cm, showing close relationship with the optic apparatus (<3 mm) or skull base dural spreading, were treated by FR. Secondarily, with the advent of new devices and our growing experience, these criteria have evolved. The median follow-up period was 88.6 months (range, 42-168 mo) for Group I and 63.6 months (range, 48-92 mo) for Group II. According to Sekhar's classification, 26 (68.4%) patients were Grade III to IV in Group I and 10 (27.8%) patients in Group II (P < 0.05); 23 (60.5%) patients had extensive lesions in Group I and 7 (19.4%) patients in Group II (P < 0.05). Mean tumor volume was 13.5 cm in Group I and 5.2 cm in Group II (P < 0.05). Actuarial progression-free survival was 94.7% and 94.4% in Group I and II, respectively. Clinically, improvement was seen for 24 (63.2%) patients in Group I and for 21 (53.8%) patients in Group II (P > 0.05). Radiologically, 11 (29%, Group I) patients and 19 (Group II, 52.7%) patients showed tumor shrinkage (P = 0.04). Transient morbidity was 10.5% in Group I and 2.8% in Group II. Permanent morbidity was 2.6% in Group I and 0% in Group II. FR and GKS radiosurgery are safe and efficient techniques in

  13. A new Gamma Knife radiosurgery paradigm: Tomosurgery

    NASA Astrophysics Data System (ADS)

    Hu, Xiaoliang

    The Leksell (Elekta, Stockholm, Sweden) Gamma Knife(TM) (LGK) is the worldwide standard-of-care for the radiosurgical treatment of a wide variety of intracranial lesions. The current LGK utilizes a step-and-shoot dose delivery mechanism where the centroid of each conformal radiation dose (i.e., the shot isocenter) requires repositioning the patient outside of the irradiation field. Perhaps the greatest challenge the LGK treatment team faces is planning the treatment of large and/or complexly shaped lesions that may be in close proximity to critical neural or vascular structures. The standard manual treatment planning approach is a time consuming procedure where additional time spent does not guarantee the identification of an increasingly optimal treatment plan. I propose a new radiosurgery paradigm which I refer to as "Tomosurgery". The Tomosurgery paradigm begins with the division of the target volume into a series of adjacent treatment slices, each with a carefully determined optimal thickness. The use of a continuously moving disk-shaped radiation shot that moves through the lesion in a raster-scanning pattern is expected to improve overall radiation dose conformality and homogeneity. The Tomosurgery treatment planning algorithm recruits a two-stage optimization strategy, which first plans each treatment slice as a simplified 2D problem and secondly optimally assembles the 2D treatment plans into the final 3D treatment plan. Tested on 11 clinical LGK cases, the automated inversely-generated Tomosurgery treatment plans performed as well or better than the neurosurgeon's manually created treatment plans across all criteria: (a) dose volume histograms, (b) dose homogeneity, (c) dose conformality, and (d) critical structure damage, where applicable. LGK Tomosurgery inverse treatment planning required much less time than standard of care, manual (i.e., forward) LGK treatment planning procedures. These results suggest that Tomosurgery might provide an improvement

  14. Early versus late Gamma Knife radiosurgery following transsphenoidal surgery for nonfunctioning pituitary macroadenomas: a multicenter matched-cohort study.

    PubMed

    Pomeraniec, I Jonathan; Kano, Hideyuki; Xu, Zhiyuan; Nguyen, Brandon; Siddiqui, Zaid A; Silva, Danilo; Sharma, Mayur; Radwan, Hesham; Cohen, Jonathan A; Dallapiazza, Robert F; Iorio-Morin, Christian; Wolf, Amparo; Jane, John A; Grills, Inga S; Mathieu, David; Kondziolka, Douglas; Lee, Cheng-Chia; Wu, Chih-Chun; Cifarelli, Christopher P; Chytka, Tomas; Barnett, Gene H; Lunsford, L Dade; Sheehan, Jason P

    2017-10-27

    OBJECTIVE Gamma Knife radiosurgery (GKRS) is frequently used to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of imaging-defined progression of tumor. Given the high incidence of adenoma progression after subtotal resection over time, the present study intended to evaluate the effect of timing of radiosurgery on outcome. METHODS This is a multicenter retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS from 1987 to 2015 at 9 institutions affiliated with the International Gamma Knife Research Foundation. Patients were matched by adenoma and radiosurgical parameters and stratified based on the interval between last resection and radiosurgery. Operative results, imaging data, and clinical outcomes were compared across groups following early (≤ 6 months after resection) or late (> 6 months after resection) radiosurgery. RESULTS After matching, 222 patients met the authors' study criteria (from an initial collection of 496 patients) and were grouped based on early (n = 111) or late (n = 111) GKRS following transsphenoidal surgery. There was a greater risk of tumor progression after GKRS (p = 0.013) and residual tumor (p = 0.038) in the late radiosurgical group over a median imaging follow-up period of 68.5 months. No significant difference in the occurrence of post-GKRS endocrinopathy was observed (p = 0.68). Thirty percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 27% in the late cohort (p = 0.84). Fourteen percent of the patients in the early group and 25% of the patients in the late group experienced the resolution of endocrine dysfunction after original presentation (p = 0.32). CONCLUSIONS In this study, early GKRS was associated with a lower risk of

  15. Two-year experience with the commercial Gamma Knife Check software.

    PubMed

    Xu, Andy Yuanguang; Bhatnagar, Jagdish; Bednarz, Greg; Novotny, Josef; Flickinger, John; Lunsford, L Dade; Huq, M Saiful

    2016-07-08

    The Gamma Knife Check software is an FDA approved second check system for dose calculations in Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy and the stability of the commercial software package as a tool for independent dose verification. The Gamma Knife Check software version 8.4 was commissioned for a Leksell Gamma Knife Perfexion and a 4C unit at the University of Pittsburgh Medical Center in May 2012. Independent dose verifications were performed using this software for 319 radiosurgery cases on the Perfexion and 283 radiosurgery cases on the 4C units. The cases on each machine were divided into groups according to their diagnoses, and an averaged absolute percent dose difference for each group was calculated. The percentage dose difference for each treatment target was obtained as the relative difference between the Gamma Knife Check dose and the dose from the tissue maximum ratio algorithm (TMR 10) from the GammaPlan software version 10 at the reference point. For treatment plans with imaging skull definition, results obtained from the Gamma Knife Check software using the measurement-based skull definition method are used for comparison. The collected dose difference data were also analyzed in terms of the distance from the treatment target to the skull, the number of treatment shots used for the target, and the gamma angles of the treatment shots. The averaged percent dose differences between the Gamma Knife Check software and the GammaPlan treatment planning system are 0.3%, 0.89%, 1.24%, 1.09%, 0.83%, 0.55%, 0.33%, and 1.49% for the trigeminal neuralgia, acoustic neuroma, arteriovenous malformation (AVM), meningioma, pituitary adenoma, glioma, functional disorders, and metastasis cases on the Perfexion unit. The corresponding averaged percent dose differences for the 4C unit are 0.33%, 1.2%, 2.78% 1.99%, 1.4%, 1.92%, 0.62%, and 1.51%, respectively. The dose difference is, in general, larger for treatment targets in the

  16. Two‐year experience with the commercial Gamma Knife Check software

    PubMed Central

    Bhatnagar, Jagdish; Bednarz, Greg; Novotny, Josef; Flickinger, John; Lunsford, L. Dade; Huq, M. Saiful

    2016-01-01

    The Gamma Knife Check software is an FDA approved second check system for dose calculations in Gamma Knife radiosurgery. The purpose of this study was to evaluate the accuracy and the stability of the commercial software package as a tool for independent dose verification. The Gamma Knife Check software version 8.4 was commissioned for a Leksell Gamma Knife Perfexion and a 4C unit at the University of Pittsburgh Medical Center in May 2012. Independent dose verifications were performed using this software for 319 radiosurgery cases on the Perfexion and 283 radiosurgery cases on the 4C units. The cases on each machine were divided into groups according to their diagnoses, and an averaged absolute percent dose difference for each group was calculated. The percentage dose difference for each treatment target was obtained as the relative difference between the Gamma Knife Check dose and the dose from the tissue maximum ratio algorithm (TMR 10) from the GammaPlan software version 10 at the reference point. For treatment plans with imaging skull definition, results obtained from the Gamma Knife Check software using the measurement‐based skull definition method are used for comparison. The collected dose difference data were also analyzed in terms of the distance from the treatment target to the skull, the number of treatment shots used for the target, and the gamma angles of the treatment shots. The averaged percent dose differences between the Gamma Knife Check software and the GammaPlan treatment planning system are 0.3%, 0.89%, 1.24%, 1.09%, 0.83%, 0.55%, 0.33%, and 1.49% for the trigeminal neuralgia, acoustic neuroma, arteriovenous malformation (AVM), meningioma, pituitary adenoma, glioma, functional disorders, and metastasis cases on the Perfexion unit. The corresponding averaged percent dose differences for the 4C unit are 0.33%, 1.2%, 2.78% 1.99%, 1.4%, 1.92%, 0.62%, and 1.51%, respectively. The dose difference is, in general, larger for treatment targets in the

  17. Ten-Year Survival of a Patient Treated with Stereotactic Gamma Knife Radiosurgery for Brain Metastases from Colon Cancer with Ovarian and Lymph Node Metastases: A Case Report.

    PubMed

    Morinaga, Nobuhiro; Tanaka, Naritaka; Shitara, Yoshinori; Ishizaki, Masatoshi; Yoshida, Takatomo; Kouga, Hideaki; Wakabayashi, Kazuki; Fukuchi, Minoru; Tsunoda, Yoshiyuki; Kuwano, Hiroyuki

    2016-01-01

    Brain metastasis from colorectal cancer is infrequent and carries a poor prognosis. Herein, we present a patient alive 10 years after the identification of a first brain metastasis from sigmoid colon cancer. A 39-year-old woman underwent sigmoidectomy for sigmoid colon cancer during an emergency operation for pelvic peritonitis. The pathological finding was moderately differentiated adenocarcinoma. Eleven months after the sigmoidectomy, a metastatic lesion was identified in the left ovary. Despite local radiotherapy followed by chemotherapy, the left ovarian lesion grew, so resection of the uterus and bilateral ovaries was performed. Adjuvant chemotherapy with tegafur-uracil (UFT)/calcium folinate (leucovorin, LV) was initiated. Seven months after resection of the ovarian lesion, brain metastases appeared in the bilateral frontal lobes and were treated with stereotactic Gamma Knife radiosurgery. Cervical and mediastinal lymph node metastases were also diagnosed, and irradiation of these lesions was performed. After radiotherapy, 10 courses of oxaliplatin and infused fluorouracil plus leucovorin (FOLFOX) were administered. During FOLFOX administration, recurrent left frontal lobe brain metastasis was diagnosed and treated with stereotactic Gamma Knife radiosurgery. In this case, the brain metastases were well treated with stereotactic Gamma Knife radiosurgery, and the systemic disease arising from sigmoid colon cancer has been kept under control with chemotherapies, surgical resection, and radiotherapy.

  18. Gamma Knife Radiosurgery for Pediatric Arteriovenous Malformations: A Canadian Experience.

    PubMed

    Zeiler, Fred A; Janik, Maciej K; McDonald, Patrick J; Kaufmann, Anthony M; Fewer, Derek; Butler, Jim; Schroeder, Garry; West, Michael

    2016-01-01

    Gamma Knife (GK) radiosurgery for pediatric arteriovenous malformations (AVM) of the brain presents a non-invasive treatment option. We report our institutional experience with GK for pediatric AVMs. We performed a retrospective review of all pediatric patients treated with GK for cerebral AVMs at our institution from November 2003 up to and including September 2014. Patient demographics, AVM characteristics, treatment parameters and AVM responses were recorded. Nineteen patients were treated, with 4 lost to follow-up. The mean age was 14.2 years (range. 7-18 years), with 10 being males (52.6%). The mean AVM diameter and volume were 2.68 cm and 3.10 cm3 respectively. The mean Spetzler-Martin (SM) and Pollock grades of the treated AVMs were 2.4 and 0.99 respectively. The mean follow-up was 62 months. All AVMs treated demonstrated a response on follow-up imaging. Nine of 15 (60.0%) patients displayed obliteration of their AVMs. Nine of 11 patients with a minimum of 3 years follow-up (81.8%) displayed obliteration, with SM and Pollock grades correlating to the chance of obliteration in this group. Two patients developed post-GK edema requiring short course dexamethasone therapy. No other major complications occurred. No permanent complications occurred. GK radiosurgery for pediatric AVMs offers a safe and effective treatment option, with low permanent complication rates during early follow-up.

  19. Benign orbital apex tumors treated with multisession gamma knife radiosurgery.

    PubMed

    Goh, Alice Siew Ching; Kim, Yoon-Duck; Woo, Kyung In; Lee, Jung-Il

    2013-03-01

    The orbital apex is an important anatomic landmark that hosts numerous critical neurovascular structures. Tumor resection performed at this complex region poses a therapeutic challenge to orbital surgeons and often is associated with significant visual morbidity. This article reports the efficacy and safety of multisession gamma knife radiosurgery (GKRS) in benign, well-circumscribed tumors located at the orbital apex. Retrospective interventional case series. Five patients with visual disturbances resulting from a benign, well-circumscribed orbital apex tumor (3 cases of cavernous hemangioma and 2 cases of schwannoma). Each patient treated with GKRS with a total radiation dose of 20 Gy in 4 sessions (5 Gy in each session with an isodose line of 50%) delivered to the tumor margin. Best-corrected visual acuity, visual field changes, orbital imaging, tumor growth control, and side effects of radiation. All patients demonstrated improvement in visual acuity, pupillary responses, color vision, and visual field. Tumor shrinkage was observed in all patients and remained stable until the last follow-up. No adverse events were noted during or after the radiosurgery. None of the patients experienced any radiation-related ocular morbidity. From this experience, multisession GKRS seems to be an effective management strategy to treat solitary, benign, well-circumscribed orbital apex tumors. Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  20. Histopathological observations on vestibular schwannomas after Gamma Knife radiosurgery: the Marseille experience.

    PubMed

    Szeifert, G T; Figarella-Branger, D; Roche, P-H; Régis, J

    2004-06-01

    Radiosurgery has become a successful treatment modality in the management of vestibular schwannomas (VS) during the past four decades. Although the number of treated cases has been increasing continuously we know relatively little about the pathological effect of high dose irradiation on VS following radiosurgery. The purpose of this study was to analyze histopathological changes in VS after Leksell Gamma Knife (LGK) radiosurgery. Out of a series of 1350 VS cases treated with LGK surgery 22 patients underwent craniotomy for tumor removal in 6-92 Months interval after radiosurgery. Surgical pathology material was available in 17 cases. Routine histological and immunohistochemical investigations were performed on the tIssue samples. Histopathological findings were compared with clinical and radiological follow-up data. Coagulation necrosis in the central part of the schwannomas surrounded with a transitional zone containing loosened tIssue structure of shrunken tumor cells covered with an outer capsule of vigorous neoplastic cells was the basic histopathological lesion. Granulation tIssue proliferation with inflammatory cell infiltration, different extent of hemorrhages and scar tIssue development was usually present. Endothelial destruction or wall damage of vascular channels was a common finding. Analyzing the follow-up data it turned out that 7 patients out of the 22 were operated on because of radiological progression only without clinical deterioration and 4 of them was removed during the latency period after radiosurgery. Results of the present histopathological study suggest that radiosurgery works with double effect on VS: it seems to destroy directly tumor cells (with necrosis or inducing apoptosis), and causes vascular damages as well. The loss of central contrast enhancement on CT and MR images following radiosurgery might be consequence of necrosis and vascular impairment. From clinical-pathological point of view we think that patients should not undergo

  1. Gamma knife radiosurgery for vestibular schwannomas: tumor control and functional preservation in 70 patients.

    PubMed

    Arthurs, Benjamin J; Lamoreaux, Wayne T; Mackay, Alexander R; Demakas, John J; Giddings, Neil A; Fairbanks, Robert K; Cooke, Barton S; Elaimy, Ameer L; Peressini, Ben; Lee, Christopher M

    2011-06-01

    We present the previously unreported outcomes of 70 patients treated with Gamma knife radiosurgery for vestibular schwannoma (VS), including comprehensive analysis of clinical outcomes and the effects of lower marginal doses. We performed a retrospective study of patients treated for VS at Gamma knife of Spokane between 2003 and 2008. Endpoints measured include tumor control, hearing preservation, and facial nerve preservation, including the effect of tumor size and marginal dose. Statistical analysis was performed with Wilcoxon signed-rank test, paired Student t test, Mann-Whitney U test, Kendall's rank correlation, Fisher exact test, and Liddell's exact χ(2) test for matched pairs. With a mean follow-up of 26 months, 93.8% of tumors either shrank or remained static after receiving a mean marginal dose of 12.7 Gy. Tumor control was independent of marginal dose or tumor size. Hearing preservation was achieved in 64% of patients with serviceable function before the treatment. Hearing changes were independent of dose or tumor size. Preservation of good facial nerve function was achieved in 95% of patients. Post-treatment hydrocephalus occurred in 4.4% of patients, but no other significant morbidities were elucidated. In the treatment of VS, contemporary radiosurgical techniques and the use of marginal doses below 13 Gy offer excellent tumor control, at high rates relative to surgical intervention. These findings are independent of marginal dose and tumor size. Patients should be informed about the benefits and risks of radiosurgery and microsurgery before choosing an intervention. Further analysis of post-treatment outcomes should be encouraged as follow-up times increase and the treatment protocols continue to evolve.

  2. Vestibular schwannomas: clinical results and quality of life after microsurgery or gamma knife radiosurgery.

    PubMed

    Myrseth, Erling; Møller, Per; Pedersen, Paal-Henning; Vassbotn, Flemming S; Wentzel-Larsen, Tore; Lund-Johansen, Morten

    2005-05-01

    The aim of the present study was to evaluate the overall treatment efficacy (tumor control, facial nerve function, complications) and quality of life for patients treated primarily for unilateral vestibular schwannomas of 30 mm or less, either by microsurgery or by gamma knife (GK) radiosurgery. The results for the two treatment groups are compared with each other, with main emphasis on the long-term quality of life. This is a retrospective study of 189 consecutive patients, 86 treated by microsurgery and 103 by gamma knife. The mean observation time was 5.9 years. All patients had a magnetic resonance imaging scan and clinical evaluation performed toward the end of the study. To evaluate the quality of life, we used two standardized questionnaires, the Glasgow Benefit Inventory and Short-Form 36. The questionnaires were sent to the 168 living patients. The reply rate was 83.3%. A total of 79.8% of the patients in the microsurgery group and 94.8% of the GK patients had a good facial nerve function (House-Brackmann Grade 1-2). Hearing was usually lost after microsurgery, whereas the GK patients had preserved hearing, which often became reduced over the years after the treatment. The treatment efficacy, defined as no need for additional treatment, was similar for the two treatment modalities. Quality of life was reduced compared with normative data, being most reduced in the microsurgery group. Some of the quality of life questions showed an association with facial nerve function and sex. Posttreatment facial nerve function, hearing, complication rates, and quality of life were all significantly in favor of GK radiosurgery.

  3. Gamma Knife radiosurgery for hypothalamic hamartoma preserves endocrine functions.

    PubMed

    Castinetti, Frederic; Brue, Thierry; Morange, Isabelle; Carron, Romain; Régis, Jean

    2017-06-01

    Gamma Knife radiosurgery (GK) is an effective treatment for hypothalamic hamartoma. No precise data are available on the risk of endocrine side effects of this treatment. In this study, 34 patients with hypothalamic hamartoma (HH) were followed prospectively at the Department of Endocrinology, La Timone Hospital, Marseille, France, for a mean follow-up of >2 years (mean ± standard deviation [SD] 3.6 ± 2 years). Initial pre- and post-GK radiosurgery evaluations were performed, including weight, body mass index (BMI), and a complete endocrinological workup. At diagnosis, eight patients presented with central precocious puberty at a mean age of 5.4 ± 2.4 years. At the time of GK (mean age 18.2 ± 11.1 years), two patients previously treated with surgery presented with luteinizing hormone/follicle-stimulating hormone (LH/FSH) deficiency. After GK, only one patient presented with a new thyrotropin-stimulating hormone (TSH) deficiency, 2 years after the procedure. The other pituitary axes remained normal in all but two patients (who had LH/FSH deficiency prior to GK). There was no significant difference between pre- and post-GK mean BMI (26.9 vs. 25.1 kg/m 2 , p = 0.59). To conclude, in this group of 34 patients, GK did not induce major endocrinologic side effects reported with all the other surgical techniques in the literature. It is, thus, a safe and effective procedure in the treatment of hypothalamic hamartoma. Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.

  4. Hearing Preservation after Low-dose Gamma Knife Radiosurgery of Vestibular Schwannomas

    PubMed Central

    HORIBA, Ayako; HAYASHI, Motohiro; CHERNOV, Mikhail; KAWAMATA, Takakazu; OKADA, Yoshikazu

    2016-01-01

    The objective of the retrospective study was to evaluate the factors associated with hearing preservation after low-dose Gamma Knife radiosurgery (GKS) of vestibular schwannomas performed according to the modern standards. From January 2005 to September 2010, 141 consecutive patients underwent such treatment in Tokyo Women’s Medical University. Mean marginal dose was 11.9 Gy (range, 11–12 Gy). The doses for the brain stem, cranial nerves (V, VII, and VIII), and cochlea were kept below 14 Gy, 12 Gy, and 4 Gy, respectively. Out of the total cohort, 102 cases with at least 24 months follow-up were analyzed. Within the median follow-up of 56 months (range, 24–99 months) the crude tumor growth control was 92% (94 cases), whereas its actuarial rate at 5 years was 93%. Out of 49 patients with serviceable hearing on the side of the tumor before GKS, 28 (57%) demonstrated its preservation at the time of the last follow-up. No one evaluated factor, namely Gardner-Robertson hearing class before irradiation, Koos tumor stage, extension of the intrameatal part of the neoplasm up to fundus, nerve of tumor origin, presence of cystic changes in the neoplasm, and cochlea dose demonstrated statistically significant association with preservation of the serviceable hearing after radiosurgery. In conclusion, GKS of vestibular schwannomas performed according to the modern standards of treatment permits to preserve serviceable hearing on the side of the tumor in more than half of the patients. The actual causes of hearing deterioration after radiosurgery remain unclear. PMID:26876903

  5. Gamma Knife radiosurgery for posterior fossa meningiomas: a multicenter study.

    PubMed

    Sheehan, Jason P; Starke, Robert M; Kano, Hideyuki; Barnett, Gene H; Mathieu, David; Chiang, Veronica; Yu, James B; Hess, Judith; McBride, Heyoung L; Honea, Norissa; Nakaji, Peter; Lee, John Y K; Rahmathulla, Gazanfar; Evanoff, Wendi A; Alonso-Basanta, Michelle; Lunsford, L Dade

    2015-06-01

    Posterior fossa meningiomas represent a common yet challenging clinical entity. They are often associated with neurovascular structures and adjacent to the brainstem. Resection can be undertaken for posterior fossa meningiomas, but residual or recurrent tumor is frequent. Stereotactic radiosurgery (SRS) has been used to treat meningiomas, and this study evaluates the outcome of this approach for those located in the posterior fossa. At 7 medical centers participating in the North American Gamma Knife Consortium, 675 patients undergoing SRS for a posterior fossa meningioma were identified, and clinical and radiological data were obtained for these cases. Females outnumbered males at a ratio of 3.8 to 1, and the median patient age was 57.6 years (range 12-89 years). Prior resection was performed in 43.3% of the patient sample. The mean tumor volume was 6.5 cm(3), and a median margin dose of 13.6 Gy (range 8-40 Gy) was delivered to the tumor. At a mean follow-up of 60.1 months, tumor control was achieved in 91.2% of cases. Actuarial tumor control was 95%, 92%, and 81% at 3, 5, and 10 years after radiosurgery. Factors predictive of tumor progression included age greater than 65 years (hazard ratio [HR] 2.36, 95% CI 1.30-4.29, p = 0.005), prior history of radiotherapy (HR 5.19, 95% CI 1.69-15.94, p = 0.004), and increasing tumor volume (HR 1.05, 95% CI 1.01-1.08, p = 0.005). Clinical stability or improvement was achieved in 92.3% of patients. Increasing tumor volume (odds ratio [OR] 1.06, 95% CI 1.01-1.10, p = 0.009) and clival, petrous, or cerebellopontine angle location as compared with petroclival, tentorial, and foramen magnum location (OR 1.95, 95% CI 1.05-3.65, p = 0.036) were predictive of neurological decline after radiosurgery. After radiosurgery, ventriculoperitoneal shunt placement, resection, and radiation therapy were performed in 1.6%, 3.6%, and 1.5%, respectively. Stereotactic radiosurgery affords a high rate of tumor control and neurological preservation

  6. MRI textures as outcome predictor for Gamma Knife radiosurgery on vestibular schwannoma

    NASA Astrophysics Data System (ADS)

    Langenhuizen, P. P. J. H.; Legters, M. J. W.; Zinger, S.; Verheul, H. B.; Leenstra, S.; de With, P. H. N.

    2018-02-01

    Vestibular schwannomas (VS) are benign brain tumors that can be treated with high-precision focused radiation with the Gamma Knife in order to stop tumor growth. Outcome prediction of Gamma Knife radiosurgery (GKRS) treatment can help in determining whether GKRS will be effective on an individual patient basis. However, at present, prognostic factors of tumor control after GKRS for VS are largely unknown, and only clinical factors, such as size of the tumor at treatment and pre-treatment growth rate of the tumor, have been considered thus far. This research aims at outcome prediction of GKRS by means of quantitative texture feature analysis on conventional MRI scans. We compute first-order statistics and features based on gray-level co- occurrence (GLCM) and run-length matrices (RLM), and employ support vector machines and decision trees for classification. In a clinical dataset, consisting of 20 tumors showing treatment failure and 20 tumors exhibiting treatment success, we have discovered that the second-order statistical metrics distilled from GLCM and RLM are suitable for describing texture, but are slightly outperformed by simple first-order statistics, like mean, standard deviation and median. The obtained prediction accuracy is about 85%, but a final choice of the best feature can only be made after performing more extensive analyses on larger datasets. In any case, this work provides suitable texture measures for successful prediction of GKRS treatment outcome for VS.

  7. Gamma Knife radiosurgery for intracranial meningiomas: Do we need to treat the dural tail? A single-center retrospective analysis and an overview of the literature.

    PubMed

    Bulthuis, Vincent J; Hanssens, Patrick E J; Lie, Suan Te; van Overbeeke, Jacobus J

    2014-01-01

    The dural tail (DT) has been described as a common feature in meningiomas. There is a great variation of tumor invasion and extent of tumor cells in the DT. Therefore, the necessity to include the whole DT in Gamma Knife radiosurgery is not clear, since inclusion increases the target volume and therefore increases the risk of complications. In this analysis, we evaluated whether the complete tail should be included as part of the target in Gamma Knife radiosurgery for meningiomas. Between June 2002 and December 2010, Gamma Knife radiosurgery was performed in 160 patients with 203 meningiomas with a DT. In 105 tumors, the diagnosis was based on magnetic resonance imaging (MRI) characteristics, and in 98 tumors, the diagnosis was confirmed by histopathologic examination after surgery. The median volume of the tumors was 3.55 cc. All tumors were treated with Gamma Knife radiosurgery with a median prescribed dose of 13 Gy (range 11-15), resulting in a median marginal dose of 11 Gy (range 10-15). Only the part of the DT closely related to the tumor mass was included in the target. The median follow-up period was 41 months (range 12-123). In image-based meningiomas, the overall local control rate was 96.2% with 2- and 5-year control rates of 98.0% and 95.1%, respectively. In WHO grade I tumors, the overall local control rate was 85.9% with 2- and 5-year control rates of 94.5% and 88.0%, respectively. The overall local control rate in World Health Organization (WHO) grade II tumors was 70.6% with control rates of 83.4% and 64.4% after 2 and 5 years, respectively. The growth of all new tumors was found in the radiation target area. No tumor growth was observed in the part of the DT that had been excluded from the target volume. We found in this study that routinely excluding the DT from the target does not lead to out-of-field tumor progression. Given the possibility that the DT is infiltrated with tumor cells, regular follow-up is needed.

  8. Gamma knife radiosurgery for glomus jugulare tumors: therapeutic advantages of minimalism in the skull base.

    PubMed

    Sharma, Manish S; Gupta, A; Kale, S S; Agrawal, D; Mahapatra, A K; Sharma, B S

    2008-01-01

    Glomus jugulare (GJ) tumors are paragangliomas found in the region of the jugular foramen. Surgery with/without embolization and conventional radiotherapy has been the traditional management option. To analyze the efficacy of gamma knife radiosurgery (GKS) as a primary or an adjunctive form of therapy. A retrospective analysis of patients who received GKS at a tertiary neurosurgical center was performed. Of the 1601 patients who underwent GKS from 1997 to 2006, 24 patients with GJ underwent 25 procedures. The average age of the cohort was 46.6 years (range, 22-76 years) and the male to female ratio was 1:2. The most common neurological deficit was IX, X, XI cranial nerve paresis (15/24). Fifteen patients received primary GKS. Mean tumor size was 8.7 cc (range 1.1-17.2 cc). The coverage achieved was 93.1% (range 90-97%) using a mean tumor margin dose of 16.4 Gy (range 12-25 Gy) at a mean isodose of 49.5% (range 45-50%). Thirteen patients (six primary and seven secondary) were available for follow-up at a median interval of 24 months (range seven to 48 months). The average tumor size was 7.9 cc (range 1.1-17.2 cc). Using a mean tumor margin dose of 16.3 Gy (range 12-20 Gy) 93.6% coverage (range 91-97%) was achieved. Six patients improved clinically. A single patient developed transient trigeminal neuralgia. Magnetic resonance imaging follow-up was available for 10 patients; seven recorded a decrease in size. There was no tumor progression. Gamma knife radiosurgery is a safe and effective primary and secondary modality of treatment for GJ.

  9. Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature.

    PubMed

    Arthurs, Benjamin J; Lamoreaux, Wayne T; Giddings, Neil A; Fairbanks, Robert K; Mackay, Alexander R; Demakas, John J; Cooke, Barton S; Lee, Christopher M

    2009-12-18

    Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities.We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions.

  10. Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations

    PubMed Central

    Raghunath, A.; Bennett, Niranjana; Arimappamagan, Arivazhagan; Bhat, Dhananjaya I.; Srinivas, Dwarakanath; Thennarasu, K.; Jamuna, R.; Somanna, Sampath

    2016-01-01

    Background: Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. Materials and Methods: This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Results: Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. Conclusions: GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated. PMID:26933340

  11. Impact on cognitive functions following gamma knife radiosurgery for cerebral arteriovenous malformations.

    PubMed

    Raghunath, A; Bennett, Niranjana; Arimappamagan, Arivazhagan; Bhat, Dhananjaya I; Srinivas, Dwarakanath; Thennarasu, K; Jamuna, R; Somanna, Sampath

    2016-01-01

    Radiosurgery is an alternative to surgical resection of arteriovenous malformation (AVM). Very few studies have addressed the concern of radiation injury to the brain and its attendant adverse effects on cognitive function. This prospective study included all patients who underwent gamma knife radiosurgery (GKRS) at our institute for cerebral AVM between 2006 and December 2008 (n = 34). All patients underwent neuropsychological evaluation before the procedure. Neuropsychological evaluation was repeated in eighteen patients 2 years following GKRS. Clinical outcome, AVM obliteration, and factors influencing outcome were analyzed in these eighteen patients. Before GKRS, more than 50% had significant impairment of neuropsychological functions compared to normal population norms. 66.6% achieved the excellent radiosurgical outcome. At 2 years follow-up, patients showed varied improvement in neuropsychological function in various categories. Pretherapeutic median value for percentage perseverative responses was 26.5 and at follow-up, it reduced to 18.2 (P = 0.039). Set shifting improved in 11 patients (61.1%), remained same in 5 patients (27.7%), and deteriorated in two patients (11.1%). Patients with a higher Spetzler-Martin grade AVM demonstrated a significantly more favorable shift in follow-up test values for set shifting function (P = 0.021). Patients with postradiation imaging changes had lesser tendency to improve in neuropsychological performance at follow-up. GKRS has no clinically harmful effect on cognitive and neuropsychological functioning in patients with brain AVM. On the contrary, there is an improvement in majority of patients at 2 years following radiosurgery when nidus is obliterated.

  12. Gamma Knife Radiosurgery for Uveal Metastases: Report of Three Cases and a Review of the Literature.

    PubMed

    Ares, William J; Tonetti, Daniel; Yu, Jenny Y; Monaco, Edward A; Flickinger, John C; Lunsford, L Dade

    2017-02-01

    Uveal metastases are ophthalmologic tumors that have historically been treated by fractionated external beam radiation therapy or invasive brachytherapy. The need for rapid response and less invasive management options led the authors to explore the use of Gamma Knife stereotactic radiosurgery (SRS) for this common problem. Interventional case series. To prevent eye movement during the procedure, all 3 patients underwent a retrobulbar anesthetic block followed by magnetic resonance imaging to detect the target. All tumors were treated in a single procedure using the 4C or Perfexion Gamma Knife. The tumors received a minimal tumor dose of 14-20 Gy. Two patients also underwent SRS for additional intracranial metastases. At follow-up, performed between 4 and 15 months after SRS, all 3 patients demonstrated a reduction in uveal tumor volumes. One patient developed decreased visual acuity secondary to radiation retinopathy. In this early experience, SRS was found to be an effective management option for uveal metastases associated with systemic cancer. Patients can be screened and treated effectively early after diagnosis using a joint approach between ophthalmologists and neurosurgeons. Systemic oncologic care can continue without interruption. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Volumetric changes and clinical outcome for petroclival meningiomas after primary treatment with Gamma Knife radiosurgery.

    PubMed

    Sadik, Zjiwar H A; Lie, Suan Te; Leenstra, Sieger; Hanssens, Patrick E J

    2018-01-26

    OBJECTIVE Petroclival meningiomas (PCMs) can cause devastating clinical symptoms due to mass effect on cranial nerves (CNs); thus, patients harboring these tumors need treatment. Many neurosurgeons advocate for microsurgery because removal of the tumor can provide relief or result in symptom disappearance. Gamma Knife radiosurgery (GKRS) is often an alternative for surgery because it can cause tumor shrinkage with improvement of symptoms. This study evaluates qualitative volumetric changes of PCM after primary GKRS and its impact on clinical symptoms. METHODS The authors performed a retrospective study of patients with PCM who underwent primary GKRS between 2003 and 2015 at the Gamma Knife Center of the Elisabeth-Tweesteden Hospital in Tilburg, the Netherlands. This study yields 53 patients. In this study the authors concentrate on qualitative volumetric tumor changes, local tumor control rate, and the effect of the treatment on trigeminal neuralgia (TN). RESULTS Local tumor control was 98% at 5 years and 93% at 7 years (Kaplan-Meier estimates). More than 90% of the tumors showed regression in volume during the first 5 years. The mean volumetric tumor decrease was 21.2%, 27.1%, and 31% at 1, 3, and 6 years of follow-up, respectively. Improvement in TN was achieved in 61%, 67%, and 70% of the cases at 1, 2, and 3 years of follow-up, respectively. This was associated with a mean volumetric tumor decrease of 25% at the 1-year follow-up to 32% at the 3-year follow-up. CONCLUSIONS GKRS for PCMs yields a high tumor control rate with a low incidence of neurological deficits. Many patients with TN due to PCM experienced improvement in TN after radiosurgery. GKRS achieves significant volumetric tumor decrease in the first years of follow-up and thereafter.

  14. Gamma knife surgery-induced ependymoma after the treatment of meningioma - a case report.

    PubMed

    Wang, Ke; Pan, Li; Che, Xiaoming; Lou, Meiqing

    2012-01-01

    Gamma knife surgery is widely used for a number of neurological disorders. However, little is known about its long-term complications such as carcinogenic risks. Here, we present a case of a radiosurgery-induced ependymoma by gamma knife surgery for the treatment of a spinal meningioma in a 7-year-old patient. In light of reviewing the previous reports, we advocate high caution in making young patients receive this treatment.

  15. Gamma Knife radiosurgery for vestibular schwannoma: case report and review of the literature

    PubMed Central

    2009-01-01

    Vestibular schwannomas, also called acoustic neuromas, are benign tumors of the vestibulocochlear nerve. Patients with these tumours almost always present with signs of hearing loss, and many also experience tinnitus, vertigo, and equilibrium problems. Following diagnosis with contrast enhanced MRI, patients may choose to observe the tumour with subsequent scans or seek active treatment in the form of microsurgery, radiosurgery, or radiotherapy. Unfortunately, definitive guidelines for treating vestibular schwannomas are lacking, because of insufficient evidence comparing the outcomes of therapeutic modalities. We present a contemporary case report, describing the finding of a vestibular schwannoma in a patient who presented with dizziness and a "clicking" sensation in the ear, but no hearing deficit. Audible clicking is a symptom that, to our knowledge, has not been associated with vestibular schwannoma in the literature. We discuss the diagnosis and patient's decision-making process, which led to treatment with Gamma Knife radiosurgery. Treatment resulted in an excellent radiographic response and complete hearing preservation. This case highlights an atypical presentation of vestibular schwannoma, associated with audible "clicks" and normal hearing. We also provide a concise review of the available literature on modern vestibular schwannoma treatment, which may be useful in guiding treatment decisions. PMID:20021676

  16. Salvage Gamma Knife Stereotactic Radiosurgery for Surgically Refractory Trigeminal Neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Little, Andrew S.; Shetter, Andrew G.; Shetter, Mary E.

    2009-06-01

    Purpose: To evaluate the clinical outcome of patients with surgically refractory trigeminal neuralgia (TN) treated with rescue gamma knife radiosurgery (GKRS). Methods and Materials: Seventy-nine patients with typical TN received salvage GKRS between 1997 and 2002 at the Barrow Neurological Institute (BNI). All patients had recurrent pain following at least one prior surgical intervention. Prior surgical interventions included percutaneous destructive procedures, microvascular decompression (MVD), or GKRS. Thirty-one (39%) had undergone at least two prior procedures. The most common salvage dose was 80 Gy, although 40-50 Gy was typical in patients who had received prior radiosurgery. Pain outcome was assessed usingmore » the BNI Pain Intensity Score, and quality of life was assessed using the Brief Pain Inventory. Results: Median follow-up after salvage GKRS was 5.3 years. Actuarial analysis demonstrated that at 5 years, 20% of patients were pain-free and 50% had pain relief. Pain recurred in patients who had an initial response to GKRS at a median of 1.1 years. Twenty-eight (41%) required a subsequent surgical procedure for recurrence. A multivariate Cox proportional hazards model suggested that the strongest predictor of GKRS failure was a history of prior MVD (p=0.029). There were no instances of serious morbidity or mortality. Ten percent of patients developed worsening facial numbness and 8% described their numbness as 'very bothersome.' Conclusions: GKRS salvage for refractory TN is well tolerated and results in long-term pain relief in approximately half the patients treated. Clinicians may reconsider using GKRS to salvage patients who have failed prior MVD.« less

  17. Long-Term Outcome of Gamma Knife Radiosurgery for Treatment of Typical Trigeminal Neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Han, Jung Ho; Kim, Dong Gyu, E-mail: gknife@plaza.snu.ac.k; Chung, Hyun-Tai

    2009-11-01

    Purpose: To analyze the long-term outcomes of patients with typical trigeminal neuralgia treated with gamma knife radiosurgery (GKRS). Patients and Methods: A total of 62 consecutive patients with typical trigeminal neuralgia were treated with GKRS between 1998 and 2004. Of the 62 patients, 2 were lost to follow-up; the remaining 60 patients were followed for >12 months. The mean prescribed maximal dose was 79.7 Gy (range, 75-80), using a 4-mm shot. Results: Of the 60 patients, 48 were followed for >4 years. An additional 3 patients, followed for <4 years, experienced recurrent pain after a favorable initial response and weremore » incorporated into the long-term response analysis. Of these 51 patients (mean age, 61 +- 11 years; 37 women [72.5%]; and mean follow-up duration, 58 +- 14 months), 46 (90.2%) responded to GKRS, as demonstrated by an improvement in their Barrow Neurological Institute pain intensity score. Of the 46 patients, 24 (52.2%) had pain recurrence. The actuarial recurrence-free survival rate was 84.8%, 76.1%, 69.6%, 63.0%, and 45.8% at 1, 2, 3, 4, and 5 years after radiosurgery, respectively. Patient age >70 years correlated with a favorable outcome in terms of pain recurrence after radiosurgery (hazard ratio, 0.125; 95% confidence interval, 0.016-0.975; p = .047) on multivariate analysis. Conclusion: GKRS seems to be an effective treatment modality for patients with typical trigeminal neuralgia considering the initial response rate; however, fewer than one-half of patients might continue to benefit from GKRS after long-term follow-up. Elderly patients might be good candidates for radiosurgery considering the long-term durability of efficacy.« less

  18. Novel biomarker identification using metabolomic profiling to differentiate radiation necrosis and recurrent tumor following Gamma Knife radiosurgery.

    PubMed

    Lu, Alex Y; Turban, Jack L; Damisah, Eyiyemisi C; Li, Jie; Alomari, Ahmed K; Eid, Tore; Vortmeyer, Alexander O; Chiang, Veronica L

    2017-08-01

    OBJECTIVE Following an initial response of brain metastases to Gamma Knife radiosurgery, regrowth of the enhancing lesion as detected on MRI may represent either radiation necrosis (a treatment-related inflammatory change) or recurrent tumor. Differentiation of radiation necrosis from tumor is vital for management decision making but remains difficult by imaging alone. In this study, gas chromatography with time-of-flight mass spectrometry (GC-TOF) was used to identify differential metabolite profiles of the 2 tissue types obtained by surgical biopsy to find potential targets for noninvasive imaging. METHODS Specimens of pure radiation necrosis and pure tumor obtained from patient brain biopsies were flash-frozen and validated histologically. These formalin-free tissue samples were then analyzed using GC-TOF. The metabolite profiles of radiation necrosis and tumor samples were compared using multivariate and univariate statistical analysis. Statistical significance was defined as p ≤ 0.05. RESULTS For the metabolic profiling, GC-TOF was performed on 7 samples of radiation necrosis and 7 samples of tumor. Of the 141 metabolites identified, 17 (12.1%) were found to be statistically significantly different between comparison groups. Of these metabolites, 6 were increased in tumor, and 11 were increased in radiation necrosis. An unsupervised hierarchical clustering analysis found that tumor had elevated levels of metabolites associated with energy metabolism, whereas radiation necrosis had elevated levels of metabolites that were fatty acids and antioxidants/cofactors. CONCLUSIONS To the authors' knowledge, this is the first tissue-based metabolomics study of radiation necrosis and tumor. Radiation necrosis and recurrent tumor following Gamma Knife radiosurgery for brain metastases have unique metabolite profiles that may be targeted in the future to develop noninvasive metabolic imaging techniques.

  19. Repeat Gamma Knife Radiosurgery for Trigeminal Neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aubuchon, Adam C., E-mail: acaubuchon@gmail.com; Chan, Michael D.; Lovato, James F.

    2011-11-15

    Purpose: Repeat gamma knife stereotactic radiosurgery (GKRS) for recurrent or persistent trigeminal neuralgia induces an additional response but at the expense of an increased incidence of facial numbness. The present series summarized the results of a repeat treatment series at Wake Forest University Baptist Medical Center, including a multivariate analysis of the data to identify the prognostic factors for treatment success and toxicity. Methods and Materials: Between January 1999 and December 2007, 37 patients underwent a second GKRS application because of treatment failure after a first GKRS treatment. The mean initial dose in the series was 87.3 Gy (range, 80-90).more » The mean retreatment dose was 84.4 Gy (range, 60-90). The dosimetric variables recorded included the dorsal root entry zone dose, pons surface dose, and dose to the distal nerve. Results: Of the 37 patients, 81% achieved a >50% pain relief response to repeat GKRS, and 57% experienced some form of trigeminal dysfunction after repeat GKRS. Two patients (5%) experienced clinically significant toxicity: one with bothersome numbness and one with corneal dryness requiring tarsorraphy. A dorsal root entry zone dose at repeat treatment of >26.6 Gy predicted for treatment success (61% vs. 32%, p = .0716). A cumulative dorsal root entry zone dose of >84.3 Gy (72% vs. 44%, p = .091) and a cumulative pons surface dose of >108.5 Gy (78% vs. 44%, p = .018) predicted for post-GKRS numbness. The presence of any post-GKRS numbness predicted for a >50% decrease in pain intensity (100% vs. 60%, p = .0015). Conclusion: Repeat GKRS is a viable treatment option for recurrent trigeminal neuralgia, although the patient assumes a greater risk of nerve dysfunction to achieve maximal pain relief.« less

  20. Assessment of the accuracy and stability of frameless gamma knife radiosurgery.

    PubMed

    Chung, Hyun-Tai; Park, Woo-Yoon; Kim, Tae Hoon; Kim, Yong Kyun; Chun, Kook Jin

    2018-06-03

    The aim of this study was to assess the accuracy and stability of frameless gamma knife radiosurgery (GKRS). The accuracies of the radiation isocenter and patient couch movement were evaluated by film dosimetry with a half-year cycle. Radiation isocenter assessment with a diode detector and cone-beam computed tomography (CBCT) image accuracy tests were performed daily with a vendor-provided tool for one and a half years after installation. CBCT image quality was examined twice a month with a phantom. The accuracy of image coregistration using CBCT images was studied using magnetic resonance (MR) and computed tomography (CT) images of another phantom. The overall positional accuracy was measured in whole procedure tests using film dosimetry with an anthropomorphic phantom. The positional errors of the radiation isocenter at the center and at an extreme position were both less than 0.1 mm. The three-dimensional deviation of the CBCT coordinate system was stable for one and a half years (mean 0.04 ± 0.02 mm). Image coregistration revealed a difference of 0.2 ± 0.1 mm between CT and CBCT images and a deviation of 0.4 ± 0.2 mm between MR and CBCT images. The whole procedure test of the positional accuracy of the mask-based irradiation revealed an accuracy of 0.5 ± 0.6 mm. The radiation isocenter accuracy, patient couch movement accuracy, and Gamma Knife Icon CBCT accuracy were all approximately 0.1 mm and were stable for one and a half years. The coordinate system assigned to MR images through coregistration was more accurate than the system defined by fiducial markers. Possible patient motion during irradiation should be considered when evaluating the overall accuracy of frameless GKRS. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  1. Gamma Knife Radiosurgery of the Superior Laryngeal Neuralgia: A report of three cases.

    PubMed

    Fu, Peng; Xiong, Nan-Xiang; Abdelmaksoud, Ahmed; Huang, Yi-Zhi; Song, Guo-Bin; Zhao, Hong-Yang

    2018-05-19

    Superior laryngeal neuralgia (SLN) is a relatively rare disorder that is characterized by neck pain. There are only a few reported cases and treatment options for SLN to date. In this study, we reported 3 patients with SLN who were treated with gamma knife radiosurgery (GKRS) at the time of diagnosis. For all 3 patients, GKRS was administered using a 4-mm collimator to deliver a single shot of 80 Gy of radiation (the 100% isodose line). The target was set at the jugular foramen where the vagus and glossopharyngeal nerves emerge from the skull. Follow-up assessments were performed at 32 months,31 months, and 30 months after GKRS. The 3 patients described pain relief at 3 months, 2 days and 6 weeks. None of the patients developed neurological deficits during the follow-up period. This preliminary report provides encouraging evidence that GKRS represents an effective, safe and relatively durable noninvasive treatment option for patients with SLN. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Long-term results of Gamma-knife stereotactic radiosurgery for vestibular schwannomas in patients with type 2 neurofibromatosis.

    PubMed

    Spatola, G; Carron, R; Delsanti, C; Thomassin, J-M; Roche, P-H; Régis, J

    2016-08-12

    The aim of this study was to analyze the long-term results of Gamma-knife radiosurgery treatment of vestibular schwannomas in type 2 neurofibromatosis patients. A cohort of 129 treatments for vestibular schwannomas in 103 patients was selected from a prospectively-maintained clinical database. Tumor control was assessed by volumetric analysis of the tumor at the last follow-up. Any need of a further procedure such as microsurgical removal or second treatment was regarded as a failure of tumor control. Hearing function was assessed based on Gardner-Robertson classification. Progression-free survival and functional hearing preservation rates were estimated using the Kaplan-Meier method. The median age at treatment was 34 years with no gender predominance. The median tumor volume was 1.5cm 3 . At a median clinical follow-up of 5.9 years, five patients had died, four underwent a second radiosurgical procedure and eight underwent microsurgical resection. Progression-free survival was 88 and 75% respectively at 5 and 10 years. Hearing was considered serviceable in 70 ears and remained functional in 28 ears. Kaplan-Meier estimates for 5 and 10 years functional hearing was 47 and 34%, respectively. Three patients developed new facial nerve palsy after radiosurgery at 15 days, 6 and 19 months respectively and only one partially recovered. Five patients complained of a subjective instability worsening. Four cases developed trigeminal neuropathy. No predictive factors were found to be statistically correlated with a better hearing outcome or an improved tumor growth control. Results prove less satisfying than in sporadic unilateral schwannomas. However, the lower rate of mortality and morbidity compared with microsurgical resection may support a proactive role of Gamma-knife in this pathology. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. Magnetic resonance imaging characteristics and the prediction of outcome of vestibular schwannomas following Gamma Knife radiosurgery.

    PubMed

    Wu, Chih-Chun; Guo, Wan-Yuo; Chung, Wen-Yuh; Wu, Hisu-Mei; Lin, Chung-Jung; Lee, Cheng-Chia; Liu, Kang-Du; Yang, Huai-Che

    2017-12-01

    OBJECTIVE Gamma Knife surgery (GKS) is a promising treatment modality for patients with vestibular schwannomas (VSs), but a small percentage of patients have persistent postradiosurgical tumor growth. The aim of this study was to determine the clinical and quantitative MRI features of VS as predictors of long-term tumor control after GKS. METHODS The authors performed a retrospective study of all patients with VS treated with GKS using the Leksell Gamma Knife Unit between 2005 and 2013 at their institution. A total of 187 patients who had a minimum of 24 months of clinical and radiological assessment after radiosurgery were included in this study. Those who underwent a craniotomy with tumor removal before and after GKS were excluded. Study patients comprised 85 (45.5%) males and 102 (54.5%) females, with a median age of 52.2 years (range 20.4-82.3 years). Tumor volumes, enhancing patterns, and apparent diffusion coefficient (ADC) values were measured by region of interest (ROI) analysis of the whole tumor by serial MRI before and after GKS. RESULTS The median follow-up period was 60.8 months (range 24-128.9 months), and the median treated tumor volume was 3.54 cm 3 (0.1-16.2 cm 3 ). At last follow-up, imaging studies indicated that 150 tumors (80.2%) showed decreased tumor volume, 20 (10.7%) had stabilized, and 17 (9.1%) continued to grow following radiosurgery. The postradiosurgical outcome was not significantly correlated with pretreatment volumes or postradiosurgical enhancing patterns. Tumors that showed regression within the initial 12 months following radiosurgery were more likely to have a larger volume reduction ratio at last follow-up than those that did not (volume reduction ratio 55% vs 23.6%, respectively; p < 0.001). Compared with solid VSs, cystic VSs were more likely to regress or stabilize in the initial postradiosurgical 6-12-month period and during extended follow-up. Cystic VSs exhibited a greater volume reduction ratio at last follow-up (cystic

  4. Quality of life after gamma knife radiosurgery treatment in patients with a vestibular schwannoma: the patient’s perspective

    PubMed Central

    van Haren, Anniek E. P.; Mulder, Jef J. S.; Hanssens, Patrick E. J.; van Overbeeke, Jacobus J.; Cremers, Cor W. R. J.; Graamans, Kees

    2009-01-01

    This study evaluates the impact of gamma knife radiosurgery (GKRS) on the quality of life (QOL) of patients with a sporadic vestibular schwannoma (VS). This study pertains to 108 VS patients who had GKRS in the years 2003 through 2007. Two different QOL questionnaires were used: medical outcome study short form 36 (SF36) and Glasgow benefit inventory (GBI). Radiosurgery was performed using a Leksell 4C gamma knife. The results of the QOL questionnaires in relation to prospectively and retrospectively gathered data of the VS patients treated by GKRS. Eventually, 97 patients could be included in the study. Their mean tumor size was 17 mm (range 6–39 mm); the mean maximum dose on the tumor was 19.9 Gy (range 16–25.5 Gy) and the mean marginal dose on the tumor was 11.1 (range 9.3–12.5 Gy). SF36 scores showed results comparable to those for a normal Dutch population. GBI showed a marginal decline in QOL. No correlation was found between QOL and gender, age, tumor size, or radiation dose. Increased audiovestibular symptoms after GKRS were correlated with a decreased GBI score, and decreased symptoms were correlated with a higher QOL post-GKRS. In this study shows that GKRS for VS has little impact on the general QOL of the VS patient. However, there is a wide range in individual QOL results. Individual QOL was influenced by the audiovestibular symptoms. No predictive patient, tumor, or treatment factors for QOL outcome after GKRS could be determined. Comparison with microsurgery is difficult because of intra group variability. PMID:19894058

  5. Extracranial Facial Nerve Schwannoma Treated by Hypo-fractionated CyberKnife Radiosurgery.

    PubMed

    Sasaki, Ayaka; Miyazaki, Shinichiro; Hori, Tomokatsu

    2016-09-21

    Facial nerve schwannoma is a rare intracranial tumor. Treatment for this benign tumor has been controversial. Here, we report a case of extracranial facial nerve schwannoma treated successfully by hypo-fractionated CyberKnife (Accuray, Sunnyvale, CA) radiosurgery and discuss the efficacy of this treatment. A 34-year-old female noticed a swelling in her right mastoid process. The lesion enlarged over a seven-month period, and she experienced facial spasm on the right side. She was diagnosed with a facial schwannoma via a magnetic resonance imaging (MRI) scan of the head and neck and was told to wait until the facial nerve palsy subsides. She was referred to our hospital for radiation therapy. We planned a fractionated CyberKnife radiosurgery for three consecutive days. After CyberKnife radiosurgery, the mass in the right parotid gradually decreased in size, and the facial nerve palsy disappeared. At her eight-month follow-up, her facial spasm had completely disappeared. There has been no recurrence and the facial nerve function has been normal. We successfully demonstrated the efficacy of CyberKnife radiosurgery as an alternative treatment that also preserves neurofunction for facial nerve schwannomas.

  6. Long-Term Survival after Gamma Knife Radiosurgery in a Case of Recurrent Glioblastoma Multiforme: A Case Report and Review of the Literature

    PubMed Central

    Thumma, Sudheer R.; Elaimy, Ameer L.; Daines, Nathan; Mackay, Alexander R.; Lamoreaux, Wayne T.; Fairbanks, Robert K.; Demakas, John J.; Cooke, Barton S.; Lee, Christopher M.

    2012-01-01

    The management of recurrent glioblastoma is highly challenging, and treatment outcomes remain uniformly poor. Glioblastoma is a highly infiltrative tumor, and complete surgical resection of all microscopic extensions cannot be achieved at the time of initial diagnosis, and hence local recurrence is observed in most patients. Gamma Knife radiosurgery has been used to treat these tumor recurrences for select cases and has been successful in prolonging the median survival by 8–12 months on average for select cases. We present the unique case of a 63-year-old male with multiple sequential recurrences of glioblastoma after initial standard treatment with surgery followed by concomitant external beam radiation therapy and chemotherapy (temozolomide). The patient was followed clinically as well as with surveillance MRI scans at every 2-3-month intervals. The patient underwent Gamma Knife radiosurgery three times for 3 separate tumor recurrences, and the patient survived for seven years following the initial diagnosis with this aggressive treatment. The median survival in patients with recurrent glioblastoma is usually 8–12 months after recurrence, and this unique case illustrates that aggressive local therapy can lead to long-term survivors in select situations. We advocate that each patient treatment at the time of recurrence should be tailored to each clinical situation and desire for quality of life and improved longevity. PMID:22548078

  7. Three-dimensional dose verification of the clinical application of gamma knife stereotactic radiosurgery using polymer gel and MRI.

    PubMed

    Papagiannis, P; Karaiskos, P; Kozicki, M; Rosiak, J M; Sakelliou, L; Sandilos, P; Seimenis, I; Torrens, M

    2005-05-07

    This work seeks to verify multi-shot clinical applications of stereotactic radiosurgery with a Leksell Gamma Knife model C unit employing a polymer gel-MRI based experimental procedure, which has already been shown to be capable of verifying the precision and accuracy of dose delivery in single-shot gamma knife applications. The treatment plan studied in the present work resembles a clinical treatment case of pituitary adenoma using four 8 mm and one 14 mm collimator helmet shots to deliver a prescription dose of 15 Gy to the 50% isodose line (30 Gy maximum dose). For the experimental dose verification of the treatment plan, the same criteria as those used in the clinical treatment planning evaluation were employed. These included comparison of measured and GammaPlan calculated data, in terms of percentage isodose contours on axial, coronal and sagittal planes, as well as 3D plan evaluation criteria such as dose-volume histograms for the target volume, target coverage and conformity indices. Measured percentage isodose contours compared favourably with calculated ones despite individual point fluctuations at low dose contours (e.g., 20%) mainly due to the effect of T2 measurement uncertainty on dose resolution. Dose-volume histogram data were also found in a good agreement while the experimental results for the percentage target coverage and conformity index were 94% and 1.17 relative to corresponding GammaPlan calculations of 96% and 1.12, respectively. Overall, polymer gel results verified the planned dose distribution within experimental uncertainties and uncertainty related to the digitization process of selected GammaPlan output data.

  8. Repeated transsphenoidal surgery or gamma knife radiosurgery in recurrent cushing disease after transsphenoidal surgery.

    PubMed

    Bodaghabadi, Mohammad; Riazi, Hooman; Aran, Shima; Bitaraf, Mohammad Ali; Alikhani, Mazdak; Alahverdi, Mahmud; Mohamadi, Masoumeh; Shalileh, Keivan; Azar, Maziar

    2014-03-01

    This study compared Gamma knife radiosurgery (GKRS) and repeated transsphenoidal adenomectomy (TSA) to find the best approach for recurrence of Cushing disease (CD) after unsuccessful first TSA. Fifty-two patients with relapse of CD after TSA were enrolled and randomly underwent a second surgery or GKRS as the next therapeutic approach. They were followed for a mean period of 3.05 ± 0.8 years by physical examination and hormone measurement as well as magnetic resonance imaging. No significant difference was observed in sex ratio, mean age, adenoma type, follow-up duration, and initial hormone level between the two groups. No significant relationship was found between preoperative 24-hour free urine cortisol and disease-free months or tumor volume among both groups. Our statistical analysis showed higher recurrence-free interval in the GKRS group compared with TSA group. With longer recurrence-free interval, GKRS could be considered a good treatment alternative to repeated TSA in recurrent CD. Georg Thieme Verlag KG Stuttgart · New York.

  9. Gamma knife radiosurgery for medically and surgically refractory prolactinomas.

    PubMed

    Pouratian, Nader; Sheehan, Jason; Jagannathan, Jay; Laws, Edward R; Steiner, Ladislau; Vance, Mary L

    2006-08-01

    Experience with gamma knife radiosurgery (GKRS) for prolactinomas is limited because of the efficacy of medical and surgical intervention. Patients who are refractory to medical and/or surgical therapy may be treated with GKRS. We characterize the efficacy of GKRS for medically and surgically refractory prolactinomas. We reviewed our series of patients with prolactinomas who were treated with GKRS after failing medical and surgical intervention who had at least 1 year of follow-up. Twenty-three patients were included in analysis of endocrine outcomes (median and average follow-up of 55 and 58 mo, respectively) and 28 patients were included in analysis of imaging outcomes (median and average follow-up of 48 and 52 mo, respectively). Twenty-six percent of patients achieved a normal serum prolactin (remission) with an average time of 24.5 months. Remission was significantly associated with being off of a dopamine agonist at the time of GKRS and a tumor volume less than 3.0 cm3 (P < 0.05 for both). Long-term image-based volumetric control was achieved in 89% of patients. Complications included new pituitary hormone deficiencies in 28% of patients and cranial nerve palsy in two patients (7%). Clinical remission in 26% of treated patients is a modest result. However, because the GKRS treated tumors were refractory to other therapies and because complication rates were low, GKRS should be part of the armamentarium for treating refractory prolactinomas. Patients with tumors smaller than 3.0 cm3 and who are not receiving dopamine agonist at the time of treatment will likely benefit most.

  10. Gamma knife radiosurgery for skull-base meningiomas.

    PubMed

    Takanashi, Masami; Fukuoka, Seiji; Hojyo, Atsufumi; Sasaki, Takehiko; Nakagawara, Jyoji; Nakamura, Hirohiko

    2009-01-01

    The primary purpose of this study was to evaluate the efficacy of gamma knife radiosurgery (GKRS) when used as a treatment modality for cavernous sinus or posterior fossa skull-base meningiomas (SBMs), with particular attention given to whether or not intentional partial resection followed by GKRS constitutes an appropriate combination treatment method for larger SBMs. Of the 101 SBM patients in this series, 38 were classified as having cavernous sinus meningiomas (CSMs), and 63 presented with posterior fossa meningiomas (PFMs). The patients with no history of prior surgery (19 CSMs, 57 PFMs) were treated according to a set protocol. Small to medium-sized SBMs were treated by GKRS only. To minimize the risk of functional deficits, larger tumors were treated with the combination of intentional partial resection followed by GKRS. Residual or recurrent tumors in patients who had undergone extirpations prior to GKRS (19 CSMs, 6 PFMs) are not eligible for this treatment method (due to the surgeries not being performed as part of a combination strategy designed to preserve neurological function as the first priority). The mean follow-up period was 51.9 months (range, 6-144 months). The overall tumor control rates were 95.5% in CSMs and 98.4% in PFMs. Nearly all tumors treated with GKRS alone were well controlled and the patients had no deficits. Furthermore, none of the patients who had undergone prior surgeries experienced new neurological deficits after GKRS. While new neurological deficits appeared far less often in those receiving the combination of partial resection with subsequent GKRS, extirpations tended to be associated with not only a higher incidence of new deficits but also a significant increase in the worsening of already-existing deficits. Our results indicate that GKRS is a safe and effective primary treatment for SBMs with small to moderate tumor volumes. We also found that larger SBMs compressing the optic pathway or brain stem can be effectively

  11. Gamma Knife

    MedlinePlus

    ... equipment? How is safety ensured? What is this equipment used for? The Gamma Knife® and its associated ... in size. top of page How does the equipment work? The Gamma Knife® utilizes a technique called ...

  12. Histopathology of radiation necrosis with severe peritumoral edema after gamma knife radiosurgery for parasagittal meningioma. A report of two cases.

    PubMed

    Chen, Chien-hua; Shen, Chiung-chyi; Sun, Ming-hsi; Ho, William L; Huang, Chuan-fu; Kwan, Po-cheung

    2007-01-01

    Gamma knife radiosurgery (GKS) has been an effective treatment for meningiomas. Nevertheless, it still has certain risks. We present 2 cases of parasagittal meningioma after GKS complicated with radiation necrosis and peritumoral edema. The results of histologic examination are discussed. Two cases of parasagittal meningioma received GKS. Symptomatic peritumoral edema developed 3-4 months after GKS. Both of them underwent surgical resection of their tumor afterwards. Histologic examination showed necrotic change inside the tumor and infiltration of inflammatory cells in both cases. Hyalinization of blood vessels was seen in the 2nd case. The patients had improvement of neurologic function after surgical resection. Imaging performed 3 months after surgical resection showed alleviation of brain edema. After radiosurgery peritumoral edema tends to occur in meningiomas with a parasagittal position. Radiation necrosis, infiltration of inflammatory cells, and radiation injury to the vasculature causing hyalinization of blood vessels are suggested as the underlying histopathology. (c) 2007 S. Karger AG, Basel.

  13. Effect of the gamma knife treatment on the trigeminal nerve root in Chinese patients with primary trigeminal neuralgia.

    PubMed

    Song, Zhi-Xiu; Qian, Wei; Wu, Yu-Quan; Sun, Fang-Jie; Fei, Jun; Huang, Run-Sheng; Fang, Jing-Yu; Wu, Cai-Zhen; An, You-Ming; Wang, Daxin; Yang, Jun

    2014-01-01

    To understand the mechanism of the gamma knife treating the trigeminal neuralgia. Using the MASEP-SRRS type gamma knife treatment system, 140 Chinese patients with trigeminal neuralgia (NT) were treated in our hospital from 2002 to 2010, in which the pain relief rate reached 95% and recurrence rate was 3% only. We investigated the effect of the gamma knife treatment on the trigeminal nerve root in 20 Chinese patients with primary trigeminal neuralgia by the magnetic resonance imager (MRI) observation. 1) The cross-sectional area of trigeminal nerve root became smaller and MRI signals were lower in the treatment side than those in the non-treatment side after the gamma knife treatment of primary trigeminal neuralgia; 2) in the treatment side, the cross-sectional area of the trigeminal nerve root decreased significantly after the gamma knife treatment; 3) there was good correlation between the clinical improvement and the MRI findings; and 4) the straight distance between the trigeminal nerve root and the brainstem did not change after the gamma knife treatment. The pain relief induced the gamma knife radiosurgery might be related with the atrophy of the trigeminal nerve root in Chinese patients with primary trigeminal neuralgia.

  14. Communicating Hydrocephalus Associated with Intracranial Schwannoma Treated by Gamma Knife Radiosurgery.

    PubMed

    Park, Chang Kyu; Lee, Sung Ho; Choi, Man Kyu; Choi, Seok Keun; Park, Bong Jin; Lim, Young Jin

    2016-05-01

    Gamma knife radiosurgery (GKRS) has been established as an effective and safe treatment for intracranial schwannoma. However, serious complications can occur after GKRS, including hydrocephalus. The pathophysiology and risk factors of this disorder are not yet fully understood. The objective of the study was to assess potential risk factors for hydrocephalus after GKRS. We retrospectively reviewed the medical radiosurgical records of 244 patients who underwent GKRS to treat intracranial schwannoma. The following parameters were analyzed as potential risk factors for hydrocephalus after GKRS: age, sex, target volume, irradiation dose, prior tumor resection, treatment technique, and tumor enhancement pattern. The tumor enhancement pattern was divided into 2 groups: group A (homogeneous enhancement) and group B (heterogeneous or rim enhancement). Of the 244 patients, 14 of them (5.7%) developed communicating hydrocephalus. Communicating hydrocephalus occurred within 2 years after GKRS in most patients (92.8%). No significant association was observed between any of the parameters investigated and the development of hydrocephalus, with the exception of tumor enhancement pattern. Group B exhibited a statistically significant difference by univariate analysis (P = 0.002); this difference was also significant by multivariate analysis (P = 0.006). Because hydrocephalus is curable, patients should be closely monitored for the development of this disorder after GKRS. In particular, patients with intracranial schwannomas with irregular enhancement patterns or cysts should be meticulously observed. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Stereotactic radiosurgery - discharge

    MedlinePlus

    Gamma knife - discharge; Cyberknife - discharge; Stereotactic radiotherapy - discharge; Fractionated stereotactic radiotherapy - discharge; Cyclotrons - discharge; Linear accelerator - discharge; Lineacs - discharge; Proton beam radiosurgery - discharge

  16. Higher dose rate Gamma Knife radiosurgery may provide earlier and longer-lasting pain relief for patients with trigeminal neuralgia.

    PubMed

    Lee, John Y K; Sandhu, Sukhmeet; Miller, Denise; Solberg, Timothy; Dorsey, Jay F; Alonso-Basanta, Michelle

    2015-10-01

    Gamma Knife radiosurgery (GKRS) utilizes cobalt-60 as its radiation source, and thus dose rate varies as the fixed source decays over its half-life of approximately 5.26 years. This natural decay results in increasing treatment times when delivering the same cumulative dose. It is also possible, however, that the biological effective dose may change based on this dose rate even if the total dose is kept constant. Because patients are generally treated in a uniform manner, radiosurgery for trigeminal neuralgia (TN) represents a clinical model whereby biological efficacy can be tested. The authors hypothesized that higher dose rates would result in earlier and more complete pain relief but only if measured with a sensitive pain assessment tool. One hundred thirty-three patients were treated with the Gamma Knife Model 4C unit at a single center by a single neurosurgeon during a single cobalt life cycle from January 2006 to May 2012. All patients were treated with 80 Gy with a single 4-mm isocenter without blocking. Using an output factor of 0.87, dose rates ranged from 1.28 to 2.95 Gy/min. The Brief Pain Inventory (BPI)-Facial was administered before the procedure and at the first follow-up office visit 1 month from the procedure (mean 1.3 months). Phone calls were made to evaluate patients after their procedures as part of a retrospective study. Univariate and multivariate linear regression was performed on several independent variables, including sex, age in deciles, diagnosis, follow-up duration, prior surgery, and dose rate. In the short-term analysis (mean 1.3 months), patients' self-reported pain intensity at its worst was significantly correlated with dose rate on multivariate analysis (p = 0.028). Similarly, patients' self-reported interference with activities of daily living was closely correlated with dose rate on multivariate analysis (p = 0.067). A 1 Gy/min decrease in dose rate resulted in a 17% decrease in pain intensity at its worst and a 22% decrease

  17. Gamma Knife radiosurgery for facial nerve schwannomas: a multicenter study.

    PubMed

    Sheehan, Jason P; Kano, Hideyuki; Xu, Zhiyuan; Chiang, Veronica; Mathieu, David; Chao, Samuel; Akpinar, Berkcan; Lee, John Y K; Yu, James B; Hess, Judith; Wu, Hsiu-Mei; Chung, Wen-Yuh; Pierce, John; Missios, Symeon; Kondziolka, Douglas; Alonso-Basanta, Michelle; Barnett, Gene H; Lunsford, L Dade

    2015-08-01

    Facial nerve schwannomas (FNSs) are rare intracranial tumors, and the optimal management of these tumors remains unclear. Resection can be undertaken, but the tumor's intimate association with the facial nerve makes resection with neurological preservation quite challenging. Stereotactic radiosurgery (SRS) has been used to treat FNSs, and this study evaluates the outcome of this approach. At 8 medical centers participating in the North American Gamma Knife Consortium (NAGKC), 42 patients undergoing SRS for an FNS were identified, and clinical and radiographic data were obtained for these cases. Males outnumbered females at a ratio of 1.2:1, and the patients' median age was 48 years (range 11-76 years). Prior resection was performed in 36% of cases. The mean tumor volume was 1.8 cm(3), and a mean margin dose of 12.5 Gy (range 11-15 Gy) was delivered to the tumor. At a median follow-up of 28 months, tumor control was achieved in 36 (90%) of the 40 patients with reliable radiographic follow-up. Actuarial tumor control was 97%, 97%, 97%, and 90% at 1, 2, 3, and 5 years postradiosurgery. Preoperative facial nerve function was preserved in 38 of 42 patients, with 60% of evaluable patients having House-Brackmann scores of 1 or 2 at last follow-up. Treated patients with a House-Brackmann score of 1 to 3 were more likely to demonstrate this level of facial nerve function at last evaluation (OR 6.09, 95% CI 1.7-22.0, p = 0.006). Avoidance of temporary or permanent neurological symptoms was more likely to be achieved in patients who received a tumor margin dose of 12.5 Gy or less (log-rank test, p = 0.024) delivered to a tumor of ≤ 1 cm(3) in volume (log-rank test, p = 0.01). Stereotactic radiosurgery resulted in tumor control and neurological preservation in most FNS patients. When the tumor is smaller and the patient exhibits favorable normal facial nerve function, SRS portends a better result. The authors believe that early, upfront SRS may be the treatment of choice for

  18. Gamma Knife radiosurgery for cerebral arteriovenous malformations in children/adolescents and adults. Part II: Differences in obliteration rates, treatment-obliteration intervals, and prognostic factors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nicolato, Antonio; Lupidi, Francesco; Section of Sterotactic and Functional Neurosurgery, University of Verona and University Hospital, Verona

    2006-03-01

    Purpose: To evaluate and compare obliteration rates (OBRs) and treatment-obliteration intervals (TOIs) for cerebral arteriovenous malformations (cAVMs) treated with Gamma Knife radiosurgery in children/adolescents and adults; and to determine factors predicting the OBR and TOI in these two populations. Methods and Materials: This study concerned 62 children/adolescents and 193 adults observed for {>=}3 years. Fisher exact two-tailed and Wilcoxon rank-sum tests, multiple logistics, and Cox proportional hazard models were used for statistical analysis. Results: The overall OBR was 85.5% in children/adolescents and 87.6% in adults (p 0.671), but children/adolescents showed higher 36-month actuarial OBRs (69.35%) and shorter median TOIs (25.7more » months) than adults (66.84% and 28.2 months; p 0.006 and p = 0.017, respectively). In children/adolescents, lower Spetzler-Martin grades (p = 0.043) and younger age (p = 0.019) correlated significantly with OBRs, and lower Spetzler-Martin grades (p 0.024) and noneloquent cAVM locations (p = 0.046) with TOIs. In adults, low flow through the cAVM and <6.2-cm{sup 3} volume were associated with both OBR and TOI (p 0.012 and p = 0.002, respectively). Conclusions: The differences in OBRs within 3 years and TOIs, although slight, seem to show that pediatric cAVMs behave differently from those in adults after Gamma Knife radiosurgery.« less

  19. SU-F-P-15: Report On AAPM TG 178 Gamma Knife Dosimetry and Quality Assurance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goetsch, S

    Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocolmore » modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers Conclusion: The full TG 178 report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline of possible dosimetry protocols. The report will be reviewed by the AAPM Working Group on Recommendations for Radiotherapy External Beam Quality Assurance and then by the AAPM Science Council before publication in Medical Physics. Consultant to Elekta, Inc.« less

  20. Long-Term Survival of a Patient with Brainstem and Recurrent Brain Metastasis from Stage IV Nonsmall Cell Lung Cancer Treated with Multiple Gamma Knife Radiosurgeries and Craniotomies: A Case Report and Review of the Literature

    PubMed Central

    Lamm, Andrew F.; Elaimy, Ameer L.; Mackay, Alexander R.; Fairbanks, Robert K.; Demakas, John J.; Cooke, Barton S.; Lee, Christopher M.; Taylor, Blake S.; Lamoreaux, Wayne T.

    2012-01-01

    The prognosis of patients diagnosed with stage IV nonsmall cell lung cancer that have brain and brainstem metastasis is very poor, with less than a third surviving a year past their initial date of diagnosis. We present the rare case of a 57-year-old man who is a long-term survivor of brainstem and recurrent brain metastasis, after aggressive treatment. He is now five and a half years out from diagnosis and continues to live a highly functional life without evidence of disease. Four separate Gamma Knife stereotactic radiosurgeries in conjunction with two craniotomies were utilized since his initial diagnosis to treat recurrent brain metastasis while chemoradiation therapy and thoracic surgery were used to treat his primary disease in the right upper lung. In his situation, Gamma Knife radiosurgery proved to be a valuable, safe, and effective tool for the treatment of multiply recurrent brain metastases within critical normal structures. PMID:23056973

  1. MAGAT gel and EBT2 film‐based dosimetry for evaluating source plugging‐based treatment plan in Gamma Knife stereotactic radiosurgery

    PubMed Central

    Vivekanandhan, S.; Kale, S.S.; Rath, G.K.; Senthilkumaran, S.; Thulkar, S.; Subramani, V.; Laviraj, M.A.; Bisht, R.K.; Mahapatra, A.K.

    2012-01-01

    This work illustrates a procedure to assess the overall accuracy associated with Gamma Knife treatment planning using plugging. The main role of source plugging or blocking is to create dose falloff in the junction between a target and a critical structure. We report the use of MAGAT gel dosimeter for verification of an experimental treatment plan based on plugging. The polymer gel contained in a head‐sized glass container simulated all major aspects of the treatment process of Gamma Knife radiosurgery. The 3D dose distribution recorded in the gel dosimeter was read using a 1.5T MRI scanner. Scanning protocol was: CPMG pulse sequence with 8 equidistant echoes, TR=7 s, echo step=14 ms, pixel size=0.5 mm x 0.5 mm, and slice thickness of 2 mm. Using a calibration relationship between absorbed dose and spin‐spin relaxation rate (R2), we converted R2 images to dose images. Volumetric dose comparison between treatment planning system (TPS) and gel measurement was accomplished using an in‐house MATLAB‐based program. The isodose overlay of the measured and computed dose distribution on axial planes was in close agreement. Gamma index analysis of 3D data showed more than 94% voxel pass rate for different tolerance criteria of 3%/2 mm, 3%/1 mm and 2%/2 mm. Film dosimetry with GAFCHROMIC EBT 2 film was also performed to compare the results with the calculated TPS dose. Gamma index analysis of film measurement for the same tolerance criteria used for gel measurement evaluation showed more than 95% voxel pass rate. Verification of gamma plan calculated dose on account of shield is not part of acceptance testing of Leksell Gamma Knife (LGK). Through this study we accomplished a volumetric comparison of dose distributions measured with a polymer gel dosimeter and Leksell GammaPlan (LGP) calculations for plans using plugging. We propose gel dosimeter as a quality assurance (QA) tool for verification of plug‐based planning. PACS number: 87.53.Ly, 87.55.‐x, 87

  2. Clinical Outcomes of Gamma Knife Radiosurgery in the Treatment of Patients with Trigeminal Neuralgia

    PubMed Central

    Elaimy, Ameer L.; Hanson, Peter W.; Lamoreaux, Wayne T.; Mackay, Alexander R.; Demakas, John J.; Fairbanks, Robert K.; Cooke, Barton S.; Thumma, Sudheer R.; Lee, Christopher M.

    2012-01-01

    Since its introduction by Leksell, Gamma Knife radiosurgery (GKRS) has become increasingly popular as a management approach for patients diagnosed with trigeminal neuralgia (TN). For this reason, we performed a modern review of the literature analyzing the efficacy of GKRS in the treatment of patients who suffer from TN. For patients with medically refractory forms of the condition, GKRS has proven to be an effective initial and repeat treatment option. Cumulative research suggests that patients treated a single time with GKRS exhibit similar levels of facial pain control when compared to patients treated multiple times with GKRS. However, patients treated on multiple occasions with GKRS are more likely to experience facial numbness and other facial sensory changes when compared to patients treated once with GKRS. Although numerous articles have reported MVD to be superior to GKRS in achieving facial pain relief, the findings of these comparison studies are weakened by the vast differences in patient age and comorbidities between the two studied groups and cannot be considered conclusive. Questions remain regarding optimal GKRS dosing and targeting strategies, which warrants further investigation into this controversial matter. PMID:22229034

  3. Therapeutic Effect of Gamma Knife Radiosurgery for Multiple Brain Metastases

    PubMed Central

    Lee, Chul-Kyu; Lee, Sang Ryul; Cho, Jin Mo; Yang, Kyung Ah

    2011-01-01

    Objective The aim of this study is to evaluate the therapeutic effects of gamma knife radiosurgery (GKRS) in patients with multiple brain metastases and to investigate prognostic factors related to treatment outcome. Methods We retrospectively reviewed clinico-radiological and dosimetric data of 36 patients with 4-14 brain metastases who underwent GKRS for 264 lesions between August 2008 and April 2011. The most common primary tumor site was the lung (n=22), followed by breast (n=7). At GKRS, the median Karnofsky performance scale score was 90 and the mean tumor volume was 1.2 cc (0.002-12.6). The mean prescription dose of 17.8 Gy was delivered to the mean 61.1% isodose line. Among 264 metastases, 175 lesions were assessed for treatment response by at least one imaging follow-up. Results The overall median survival after GKRS was 9.1±1.7 months. Among various factors, primary tumor control was a significant prognostic factor (11.1±1.3 months vs. 3.3±2.4 months, p=0.031). The calculated local tumor control rate at 6 and 9 months after GKRS were 87.9% and 84.2%, respectively. Paddick's conformity index (>0.75) was significantly related to local tumor control. The actuarial peritumoral edema reduction rate was 22.4% at 6 months. Conclusion According to our results, GKRS can provide beneficial effect for the patients with multiple (4 or more) brain metastases, when systemic cancer is controlled. And, careful dosimetry is essential for local tumor control. Therefore, GKRS can be considered as one of the treatment modalities for multiple brain metastase. PMID:22102945

  4. Clinical outcomes following salvage Gamma Knife radiosurgery for recurrent glioblastoma

    PubMed Central

    Larson, Erik W; Peterson, Halloran E; Lamoreaux, Wayne T; MacKay, Alexander R; Fairbanks, Robert K; Call, Jason A; Carlson, Jonathan D; Ling, Benjamin C; Demakas, John J; Cooke, Barton S; Lee, Christopher M

    2014-01-01

    Glioblastoma multiforme (GBM) is the most common malignant primary brain tumor with a survival prognosis of 14-16 mo for the highest functioning patients. Despite aggressive, multimodal upfront therapies, the majority of GBMs will recur in approximately six months. Salvage therapy options for recurrent GBM (rGBM) are an area of intense research. This study compares recent survival and quality of life outcomes following Gamma Knife radiosurgery (GKRS) salvage therapy. Following a PubMed search for studies using GKRS as salvage therapy for malignant gliomas, nine articles from 2005 to July 2013 were identified which evaluated rGBM treatment. In this review, we compare Overall survival following diagnosis, Overall survival following salvage treatment, Progression-free survival, Time to recurrence, Local tumor control, and adverse radiation effects. This report discusses results for rGBM patient populations alone, not for mixed populations with other tumor histology grades. All nine studies reported median overall survival rates (from diagnosis, range: 16.7-33.2 mo; from salvage, range: 9-17.9 mo). Three studies identified median progression-free survival (range: 4.6-14.9 mo). Two showed median time to recurrence of GBM. Two discussed local tumor control. Six studies reported adverse radiation effects (range: 0%-46% of patients). The greatest survival advantages were seen in patients who received GKRS salvage along with other treatments, like resection or bevacizumab, suggesting that appropriately tailored multimodal therapy should be considered with each rGBM patient. However, there needs to be a randomized clinical trial to test GKRS for rGBM before the possibility of selection bias can be dismissed. PMID:24829861

  5. Acute necrosis after Gamma Knife surgery in vestibular schwannoma leading to multiple cranial nerve palsies.

    PubMed

    Kapitza, Sandra; Pangalu, Athina; Horstmann, Gerhard A; van Eck, Albert T; Regli, Luca; Tarnutzer, Alexander A

    2016-08-01

    We discuss a rare acute complication after Gamma Knife therapy (Elekta AB, Stockholm, Sweden) in a single patient. A 52-year-old woman presented with vertigo, facial weakness and hearing loss emerging 48hours following Gamma Knife radiosurgery for a right-sided vestibular schwannoma. Neurological examination 6days after symptom onset showed right-sided facial palsy, spontaneous left-beating nystagmus and pathologic head-impulse testing to the right. Pure-tone audiogram revealed right-sided sensorineural hearing loss. A diagnosis of acute vestibulocochlear and facial neuropathy was made. Brain MRI demonstrated focal contrast sparing within the schwannoma, likely related to acute radiation necrosis. Acute multiple cranial neuropathies of the cerebellopontine angle after Gamma Knife treatment should raise suspicion of acute tissue damage within the schwannoma and should result in urgent MRI. Treatment with steroids may be considered based on accompanying swelling and edema. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Efficacy and tolerability of gamma knife radiosurgery in acromegaly: a 10-year follow-up study.

    PubMed

    Ronchi, Cristina L; Attanasio, Roberto; Verrua, Elisa; Cozzi, Renato; Ferrante, Emanuele; Loli, Paola; Montefusco, Laura; Motti, Enrico; Ferrari, Daniela I; Giugni, Enrico; Beck-Peccoz, Paolo; Arosio, Maura

    2009-12-01

    The long-term efficacy and safety of stereotactic radiosurgery by gamma knife (GK) still remain unknown. The aim of the study was to investigate the long-term efficacy and tolerability of GK in acromegalic patients. Retrospective analysis for a median follow-up of 10 years. Thirty-five acromegalic patients from two referral centres in Milan submitted to GK (median margin dose: 20 Gy, median % isodose: 50) between 1995 and 2004. GH/IGF-I secretion, anterior pituitary function, radiological imaging and ophthalmological data. Cure rate improved over time (up to 46% at 10 years), as did the proportion of patients achieving control on somatostatin analogues (from 12.5% at baseline to 50% at 10 years). Normal IGF-I values were observed in 82% of patients at their last visit. No visual impairment, disease recurrence, tumour growth or secondary cerebral tumour occurred. Half of the patients developed one or more new deficiencies, while two patients normalized their prior failures. In particular, new onset of clinical or subclinical hypoadrenalism occurred in 12/30 patients (40%), hypothyroidism in 3/28 (11%), hypogonadism in 2/15 (13%) and GH deficiency in 2/35 (6%). GH value at the time of GK was the best negative predictor of cure and margin dose was the best positive predictor of new hypopituitarism. Over a 10-year period after GK radiosurgery, an increasing percentage of patients achieve cure, or adequate control of the disease on pharmacological therapy, at the expense of increasing novel pituitary deficiencies. © 2009 Blackwell Publishing Ltd.

  7. P13.17STEREOTACTIC RADIOSURGERY WITH GAMMA KNIFE FOR NEUROFIBROMATOSIS 2-ASSOCIATED VESTIBULAR SCHWANNOMAS

    PubMed Central

    Presti, A. Lo; De Andrés, P.; Kusak, M.E.; De Campos, J.M.; Martínez, N.; Martínez, R.

    2014-01-01

    BACKGROUND: It is though that Stereotactic Radiosurgery (SRS) is less effective in achieving local tumor control in Neurofibromatosis 2 (NF2)-related vestibular schwannomas (VSs) compared with sporadic tumors. There is scarce literature on optimal dosing, clinical outcomes and eventual increased risk for malignant transformation among these patients. It is also possible that radiation induced tumors, in patients bearing an abnormality in a tumor suppressor gene, are misinterpreted as part of the natural history of NF2, where new tumors are expected to develop. OBJECTIVE: To evaluate the results of Gamma Knife (GK) Radiosurgery in the management of NF2-related VSs versus the sporadic VSs group treated at the same Center. METHOD: A prospectively maintained clinical database including all patients who underwent SRS for VSs was reviewed, and all subjects fulfilling the Manchester diagnostic criteria for NF2 were identified. Between 1994 and 2012, 35 patients with NF2 underwent SRS for 55 presumed VSs at our institution. The mean age at time of treatment was 30.8 years and the mean follow-up period was 4.3 years (1-14.75 years). The median margin dose used was 12 Gy and a total of 62 treatments were performed. Outcome measures, including imaging progression, hearing preservation, trigeminal and facial nerve function, were analyzed. RESULTS: Regarding tumor control 53.4% remained unchanged in size, 22.4% were smaller and 22.4% showed progression requiring further microsurgical resection or SRS. Hearing worsening occurred in 37% of tumors; 2 patients developed facial neuropathy, one of them bilateral and the other transient; trigeminal neuropathy occurred in 4 patients, one of them with previous mild impairment. No cases of malignant transformation were reported. Compared to the sporadic VSs group, NF2 patients showed lower local tumor control and higher incidence of facial and trigeminal neuropathy. CONCLUSION: NF2-related VSs treated with GK show worse clinical and

  8. Gamma Knife radiosurgery for cerebral arteriovenous malformations in children/adolescents and adults. Part I: Differences in epidemiologic, morphologic, and clinical characteristics, permanent complications, and bleeding in the latency period

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nicolato, Antonio; Lupidi, Francesco; Section of Stereotactic and Functional Neurosurgery, University of Verona and University Hospital, Verona

    Purpose: To compare the epidemiologic, morphologic, and clinical characteristics of 92 children/adolescents (Group A) and 362 adults (Group B) with cerebral arteriovenous malformations (cAVMs) considered suitable for radiosurgery; to correlate radiosurgery-related permanent complication and post-radiosurgery bleeding rates in the 75 children/adolescents and 297 adults available for follow-up. Methods and Materials: Radiosurgery was performed with a model C 201-source Co{sup 6} Leksell Gamma Unit (Elekta Instruments, Stockholm, Sweden). Fisher exact two-tailed, Wilcoxon rank-sum, and two-sample binomial exact tests were used for statistical analysis. Results: There were significant differences between the two populations in sex (p = 0.015), clinical presentation (p =more » 0.001), and location (p = 0.008). The permanent complication rate was lower in younger (1.3%) than in older patients (5.4%), although the difference was not significant (p = 0.213). The postradiosurgery bleeding rate was lower in Group A (1.3%) than in Group B (2.7%) (p = 0.694), with global actuarial bleeding rates of 0.56% per year and 1.15% per year, respectively. Conclusions: The different characteristics of child/adolescent and adult cAVMs suggest that they should be considered two distinct vascular disorders. The similar rates of radiosurgery-related complications and latency period bleeding in the two populations show that gamma knife radiosurgery does not expose young patients to a higher risk of sequelae than that for older patients.« less

  9. TH-A-BRC-02: AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Goetsch, S.

    AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance -more » Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and

  10. Management of brain metastasis in a patient with advanced epithelial ovarian carcinoma by gamma-knife radiosurgery.

    PubMed

    Nikolaoul, Marinos; Stamenković, Srdjan; Stergiou, Christos; Skarleas, Christos; Torrens, Michael

    2015-01-01

    Brain metastases from epithelial ovarian cancer (EOC) are rare events. We present a rare case of single ovarian cancer metastasis to the brain treated with gamma-knife radiosurgery (GKRS). A 65-year-old woman with advanced EOC presented with severe neurologic symptoms. A single brain metastasis of 3.2 cm with surrounding edema in the left parietal lobe was detected by brain magnetic resonance imaging (MRI) scan during the work-up. The decision to perform GKRS was due to a surgical inaccessibility of intracranial lesion. Twelve weeks after the procedure, the MRI scan showed reduction in the diameter of brain metastasis and surrounding edema and the patient returned to good mental and motor performance.The patient survived for 22 months following treatment and died from a progressive intra-abdominal disease. Prognosis of ovarian cancer patients with brain metastases is generally poor regardless of treatment. Our case shows that GKRS as primary treatment modality for the control of ovarian cancer metastases to the brain was effective and can be considered as a treatment of choice if international selection criteria are followed.

  11. Forward treatment planning techniques to reduce the normalization effect in Gamma Knife radiosurgery.

    PubMed

    Cheng, Hao-Wen; Lo, Wei-Lun; Kuo, Chun-Yuan; Su, Yu-Kai; Tsai, Jo-Ting; Lin, Jia-Wei; Wang, Yu-Jen; Pan, David Hung-Chi

    2017-11-01

    In Gamma Knife forward treatment planning, normalization effect may be observed when multiple shots are used for treating large lesions. This effect can reduce the proportion of coverage of high-value isodose lines within targets. The aim of this study was to evaluate the performance of forward treatment planning techniques using the Leksell Gamma Knife for the normalization effect reduction. We adjusted the shot positions and weightings to optimize the dose distribution and reduce the overlap of high-value isodose lines from each shot, thereby mitigating the normalization effect during treatment planning. The new collimation system, Leksell Gamma Knife Perfexion, which contains eight movable sectors, provides an additional means to reduce the normalization effect by using composite shots. We propose different techniques in forward treatment planning that can reduce the normalization effect. Reducing the normalization effect increases the coverage proportion of higher isodose lines within targets, making the high-dose region within targets more uniform and increasing the mean dose to targets. Because of the increase in the mean dose to the target after reducing the normalization effect, we can set the prescribed marginal dose at a higher isodose level and reduce the maximum dose, thereby lowering the risk of complications. © 2017 Shuang Ho Hospital-Taipei Medical University. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  12. International Radiosurgery Support Association

    MedlinePlus

    ... Tumors Brain Disorders AVMs Radiosurgery Gamma Knife Linac Radiotherapy Overview Childhood Brain Tumors Radiation Therapy Radiation Injury ... Guideline Trigeminal Neuralgia | TN Guideline ... conventional x-ray imaging procedures [New England Journal of Medicine] Read ...

  13. Feasibility of Multiple Repeat Gamma Knife Radiosurgeries for Trigeminal Neuralgia: A Case Report and Review of the Literature

    PubMed Central

    Jones, Guy C.; Elaimy, Ameer L.; Demakas, John J.; Jiang, Hansi; Lamoreaux, Wayne T.; Fairbanks, Robert K.; Mackay, Alexander R.; Cooke, Barton S.; Lee, Christopher M.

    2011-01-01

    Treatment options for trigeminal neuralgia (TN) must be customized for the individual patient, and physicians must be aware of the medical, surgical, and radiation treatment modalities to prescribe optimal treatment courses for specific patients. The following case illustrates the potential for gamma knife radiosurgery (GKRS) to be repeated multiple times for the purpose of achieving facial pain control in cases of TN that have been refractory to other medical and surgical options, as well as prior GKRS. The patient described failed to achieve pain control with initial GKRS, as well as medical and surgical treatments, but experienced significant pain relief for a period of time with a second GKRS procedure and later underwent a third procedure. Only a small subset of patients have reportedly undergone more than two GKRS for TN; thus, further research and long-term clinical followup will be valuable in determining its usefulness in specific clinical situations. PMID:21904556

  14. Comparison of plan quality and delivery time between volumetric arc therapy (RapidArc) and Gamma Knife radiosurgery for multiple cranial metastases.

    PubMed

    Thomas, Evan M; Popple, Richard A; Wu, Xingen; Clark, Grant M; Markert, James M; Guthrie, Barton L; Yuan, Yu; Dobelbower, Michael C; Spencer, Sharon A; Fiveash, John B

    2014-10-01

    Volumetric modulated arc therapy (VMAT) has been shown to be feasible for radiosurgical treatment of multiple cranial lesions with a single isocenter. To investigate whether equivalent radiosurgical plan quality and reduced delivery time could be achieved in VMAT for patients with multiple intracranial targets previously treated with Gamma Knife (GK) radiosurgery. We identified 28 GK treatments of multiple metastases. These were replanned for multiarc and single-arc, single-isocenter VMAT (RapidArc) in Eclipse. The prescription for all targets was standardized to 18 Gy. Each plan was normalized for 100% prescription dose to 99% to 100% of target volume. Plan quality was analyzed by target conformity (Radiation Therapy Oncology Group and Paddick conformity indices [CIs]), dose falloff (area under the dose-volume histogram curve), as well as the V4.5, V9, V12, and V18 isodose volumes. Other end points included beam-on and treatment time. Compared with GK, multiarc VMAT improved median plan conformity (CIVMAT = 1.14, CIGK = 1.65; P < .001) with no significant difference in median dose falloff (P = .269), 12 Gy isodose volume (P = .500), or low isodose spill (P = .49). Multiarc VMAT plans were associated with markedly reduced treatment time. A predictive model of the 12 Gy isodose volume as a function of tumor number and volume was also developed. For multiple target stereotactic radiosurgery, 4-arc VMAT produced clinically equivalent conformity, dose falloff, 12 Gy isodose volume, and low isodose spill, and reduced treatment time compared with GK. Because of its similar plan quality and increased delivery efficiency, single-isocenter VMAT radiosurgery may constitute an attractive alternative to multi-isocenter radiosurgery for some patients.

  15. Gamma Knife radiosurgery of olfactory groove meningiomas provides a method to preserve subjective olfactory function.

    PubMed

    Gande, Abhiram; Kano, Hideyuki; Bowden, Gregory; Mousavi, Seyed H; Niranjan, Ajay; Flickinger, John C; Lunsford, L Dade

    2014-02-01

    Anosmia is a common outcome after resection of olfactory groove meningioma(s) (OGM) and for some patients represents a significant disability. To evaluate long term tumor control rates and preservation of subjective olfaction after Gamma Knife (GK) stereotactic radiosurgery (SRS) of OGM. We performed a retrospective chart review and telephone assessments of 41 patients who underwent GK SRS between 1987 and 2008. Clinical outcomes were stratified by full, partial or no subjective olfaction, whereas tumor control was assessed by changes in volume greater or lesser than 25%. The median clinical and imaging follow-up were 76 and 65 months, respectively. Prior to SRS, 19 (46%) patients had surgical resections and two (5%) had received fractionated radiation therapy. Twenty four patients (59%) reported a normal sense of smell, 12 (29%) reported a reduced sense of smell and five (12%) had complete anosmia. The median tumor volume was 8.5 cm(3) (range 0.6-56.1), the mean radiation dose at the tumor margin was 13 Gy (range 10-20) and the median estimated dose to the olfactory nerve was 5.1 Gy (range 1.1-18.1). At follow-up, 27 patients (66%) reported intact olfaction (three (7%) described return to a normal sense of smell), nine (22%) described partial anosmia, and five (12%) had complete anosmia. No patient reported deterioration in olfaction after SRS. Thirteen patients (32%) showed significant tumor regression, 26 (63%) had no further growth and two (5%) had progressed. The progression free tumor control rates were 97% at 1 year and 95% at 2, 10 and 20 years. Symptomatic adverse radiation effects occurred in three (7%) patients. Stereotactic radiosurgery provided both long term tumor control and preservation of olfaction.

  16. Tolerability and efficacy of gamma knife radiosurgery on hepatocellular carcinoma with portal vein tumor thrombosis

    PubMed Central

    Lu, Xiao-Jie; Dong, Jing; Ji, Li-Juan; Xiao, Li-Xin; Ling, Chang-Quan; Zhou, Jun

    2016-01-01

    This is a retrospective study on the safety and efficacy of gamma knife radiosurgery (GKR) in treating hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT). Patients with confirmed HCC and PVTT were allocated into two groups based on the treatments they received (palliative or GKR). A total of 138 patients were included (74 in the palliative group, 64 in GKR group). No significant differences in baseline characteristics existed between the two groups. Treatment-related adverse events (AEs) were recorded and compared between groups. The majority of AEs were mild to moderate and subsided naturally or after medication. There was no AE-induced death. The influences of baseline characteristics and treatment options on patients' OS were analyzed. The median OS of patients in the palliative and GKR group were 3.0 months (95% CI: 2.719-3.281) and 6.1 months (95% CI: 4.706-7.494) respectively (p = 0.003). Multivariate analysis revealed that GKR treatment, performance status 0-1, Child A, smaller tumor diameter and monolobar distribution were significant favorable prognosticators. Subgroup analyses showed OS benefit of GKR regardless of PVTT location (main or branch of PVTT). In conclusion, GKR is well tolerated in selected HCC-PVTT patients and can confer OS benefit, which needs validation in future prospective studies. PMID:26473291

  17. Gamma Knife Radiosurgery for the Treatment of Cystic Cerebral Metastases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ebinu, Julius O.; Lwu, Shelly; Monsalves, Eric

    Purpose: To assess the role of Gamma Knife radiosurgery (GKRS) in the treatment of nonsurgical cystic brain metastasis, and to determine predictors of response to GKRS. Methods: We reviewed a prospectively maintained database of brain metastases patients treated at our institution between 2006 and 2010. All lesions with a cystic component were identified, and volumetric analysis was done to measure percentage of cystic volume on day of treatment and consecutive follow-up MRI scans. Clinical, radiologic, and dosimetry parameters were reviewed to establish the overall response of cystic metastases to GKRS as well as identify potential predictive factors of response. Results:more » A total of 111 lesions in 73 patients were analyzed; 57% of lesions received prior whole-brain radiation therapy (WBRT). Lung carcinoma was the primary cancer in 51% of patients, 10% breast, 10% colorectal, 4% melanoma, and 26% other. Fifty-seven percent of the patients were recursive partitioning analysis class 1, the remainder class 2. Mean target volume was 3.3 mL (range, 0.1-23 mL). Median prescription dose was 21 Gy (range, 15-24 Gy). Local control rates were 91%, 63%, and 37% at 6, 12, and 18 months, respectively. Local control was improved in lung primary and worse in patients with prior WBRT (univariate). Only lung primary predicted local control in multivariate analysis, whereas age and tumor volume did not. Lesions with a large cystic component did not show a poorer response compared with those with a small cystic component. Conclusions: This study supports the use of GKRS in the management of nonsurgical cystic metastases, despite a traditionally perceived poorer response. Our local control rates are comparable to a matched cohort of noncystic brain metastases, and therefore the presence of a large cystic component should not deter the use of GKRS. Predictors of response included tumor subtype. Prior WBRT decreased effectiveness of SRS for local control rates.« less

  18. Dependence of normal brain integral dose and normal tissue complication probability on the prescription isodose values for γ-knife radiosurgery

    NASA Astrophysics Data System (ADS)

    Ma, Lijun

    2001-11-01

    A recent multi-institutional clinical study suggested possible benefits of lowering the prescription isodose lines for stereotactic radiosurgery procedures. In this study, we investigate the dependence of the normal brain integral dose and the normal tissue complication probability (NTCP) on the prescription isodose values for γ-knife radiosurgery. An analytical dose model was developed for γ-knife treatment planning. The dose model was commissioned by fitting the measured dose profiles for each helmet size. The dose model was validated by comparing its results with the Leksell gamma plan (LGP, version 5.30) calculations. The normal brain integral dose and the NTCP were computed and analysed for an ensemble of treatment cases. The functional dependence of the normal brain integral dose and the NCTP versus the prescribing isodose values was studied for these cases. We found that the normal brain integral dose and the NTCP increase significantly when lowering the prescription isodose lines from 50% to 35% of the maximum tumour dose. Alternatively, the normal brain integral dose and the NTCP decrease significantly when raising the prescribing isodose lines from 50% to 65% of the maximum tumour dose. The results may be used as a guideline for designing future dose escalation studies for γ-knife applications.

  19. Gamma Knife Treatment of Brainstem Metastases

    PubMed Central

    Peterson, Halloran E.; Larson, Erik W.; Fairbanks, Robert K.; MacKay, Alexander R.; Lamoreaux, Wayne T.; Call, Jason A.; Carlson, Jonathan D.; Ling, Benjamin C.; Demakas, John J.; Cooke, Barton S.; Peressini, Ben; Lee, Christopher M.

    2014-01-01

    The management of brainstem metastases is challenging. Surgical treatment is usually not an option, and chemotherapy is of limited utility. Stereotactic radiosurgery has emerged as a promising palliative treatment modality in these cases. The goal of this study is to assess our single institution experience treating brainstem metastases with Gamma Knife radiosurgery (GKRS). This retrospective chart review studied 41 patients with brainstem metastases treated with GKRS. The most common primary tumors were lung, breast, renal cell carcinoma, and melanoma. Median age at initial treatment was 59 years. Nineteen (46%) of the patients received whole brain radiation therapy (WBRT) prior to or concurrent with GKRS treatment. Thirty (73%) of the patients had a single brainstem metastasis. The average GKRS dose was 17 Gy. Post-GKRS overall survival at six months was 42%, at 12 months was 22%, and at 24 months was 13%. Local tumor control was achieved in 91% of patients, and there was one patient who had a fatal brain hemorrhage after treatment. Karnofsky performance score (KPS) >80 and the absence of prior WBRT were predictors for improved survival on multivariate analysis (HR 0.60 (p = 0.02), and HR 0.28 (p = 0.02), respectively). GKRS was an effective treatment for brainstem metastases, with excellent local tumor control. PMID:24886816

  20. SU-F-J-166: Volumetric Spatial Distortions Comparison for 1.5 Tesla Versus 3 Tesla MRI for Gamma Knife Radiosurgery Scans Using Frame Marker Fusion and Co-Registration Modes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Neyman, G

    Purpose: To compare typical volumetric spatial distortions for 1.5 Tesla versus 3 Tesla MRI Gamma Knife radiosurgery scans in the frame marker fusion and co-registration frame-less modes. Methods: Quasar phantom by Modus Medical Devices Inc. with GRID image distortion software was used for measurements of volumetric distortions. 3D volumetric T1 weighted scans of the phantom were produced on 1.5 T Avanto and 3 T Skyra MRI Siemens scanners. The analysis was done two ways: for scans with localizer markers from the Leksell frame and relatively to the phantom only (simulated co-registration technique). The phantom grid contained a total of 2002more » vertices or control points that were used in the assessment of volumetric geometric distortion for all scans. Results: Volumetric mean absolute spatial deviations relatively to the frame localizer markers for 1.5 and 3 Tesla machine were: 1.39 ± 0.15 and 1.63 ± 0.28 mm with max errors of 1.86 and 2.65 mm correspondingly. Mean 2D errors from the Gamma Plan were 0.3 and 1.0 mm. For simulated co-registration technique the volumetric mean absolute spatial deviations relatively to the phantom for 1.5 and 3 Tesla machine were: 0.36 ± 0.08 and 0.62 ± 0.13 mm with max errors of 0.57 and 1.22 mm correspondingly. Conclusion: Volumetric spatial distortions are lower for 1.5 Tesla versus 3 Tesla MRI machines localized with markers on frames and significantly lower for co-registration techniques with no frame localization. The results show the advantage of using co-registration technique for minimizing MRI volumetric spatial distortions which can be especially important for steep dose gradient fields typically used in Gamma Knife radiosurgery. Consultant for Elekta AB.« less

  1. Five-year Survival After Surgical Removal and Gamma Knife Stereotactic Radiosurgery for a Cerebellar Metastasis from an Esophagogastric Junction Cancer: A Case Report and Literature Review

    PubMed Central

    KANAZAWA, YOSHIKAZU; FUJITA, ITSUO; KAKINUMA, DAISUKE; AOKI, YUTO; KANNO, HITOSHI; ARAI, HIROKI; MATSUNO, KUNIHIKO; SHIMODA, TOMOHIRO; MATSUTANI, TAKESHI; HAGIWARA, NOBUTOSHI; NOMURA, TSUTOMU; YAMADA, TAKESHI; KATO, SHUNJI; NAITO, ZENYA; TAKASAKI, HIDEAKI; UCHIDA, EIJI

    2017-01-01

    Brain metastases originating from esophageal or gastric cancer are rare, accounting for 2.1-3.3% of all brain tumors registered in Japan. There are no established therapeutic measures for brain metastases, which accordingly have a poor prognosis. We present here a patient who survived for 5 years after surgery and gamma knife treatment of a cerebellar metastasis from esophagogastric adenocarcinoma. The primary gastric cancer was treated by laparotomy with total gastrectomy, splenectomy, and D2 lymphadenectomy. It was diagnosed as a esophagogastric junction Siewert type II tumor, type 3, tub1-2, pT3 (SS), pN1, and stage IIB on histopathological examination of the surgical specimen. Five months postoperatively, a solitary cerebellar metastasis was identified and surgically removed, followed by 20 Gy administered by gamma knife stereotactic radiosurgery; the patient received no subsequent treatment such as chemotherapy. Five years after the primary surgery, there have been no recurrences and the patient has a good quality of life. There are very few case reports of long-term survival after surgical treatment of cerebellar metastases from esophagogastric junction cancer. We report our experience and review published case reports of surgical treatment of brain metastases from gastric cancer. PMID:29102948

  2. Neuropsychological outcomes after Gamma Knife radiosurgery for mesial temporal lobe epilepsy: a prospective multicenter study.

    PubMed

    Quigg, Mark; Broshek, Donna K; Barbaro, Nicholas M; Ward, Mariann M; Laxer, Kenneth D; Yan, Guofen; Lamborn, Kathleen

    2011-05-01

    To assess outcomes of language, verbal memory, cognitive efficiency and mental flexibility, mood, and quality of life (QOL) in a prospective, multicenter pilot study of Gamma Knife radiosurgery (RS) for mesial temporal lobe epilepsy (MTLE). RS, randomized to 20 Gy or 24 Gy comprising 5.5-7.5 ml at the 50% isodose volume, was performed on mesial temporal structures of patients with unilateral MTLE. Neuropsychological evaluations were performed at preoperative baseline, and mean change scores were described at 12 and 24 months postoperatively. QOL data were also available at 36 months. Thirty patients were treated and 26 were available for the final 24-month neuropsychological evaluation. Language (Boston Naming Test), verbal memory (California Verbal Learning Test and Logical Memory subtest of the Wechsler Memory Scale-Revised), cognitive efficiency and mental flexibility (Trail Making Test), and mood (Beck Depression Inventory) did not differ from baseline. QOL scores improved at 24 and 36 months, with those patients attaining seizure remission by month 24s accounting for the majority of the improvement. The serial changes in cognitive outcomes, mood, and QOL are unremarkable following RS for MTLE. RS may provide an alternative to open surgery, especially in those patients at risk of cognitive impairment or who desire a noninvasive alternative to open surgery. Wiley Periodicals, Inc. © 2011 International League Against Epilepsy.

  3. Effect of beam channel plugging on the outcome of gamma knife radiosurgery for trigeminal neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Massager, Nicolas; Nissim, Ouzi; Murata, Noriko

    2006-07-15

    Purpose: We studied the influence of using plugs for brainstem protection during gamma knife radiosurgery (GKR) of trigeminal neuralgia (TN), with special emphasis on irradiation doses delivered to the trigeminal nerve, pain outcomes, and incidence of trigeminal dysfunction. Methods and Materials: A GKR procedure for TN using an anterior cisternal target and a maximum dose of 90 Gy was performed in 109 patients. For 49 patients, customized beam channel blocking (plugs) were used to reduce the dose delivered to the brainstem. We measured the mean and integrated radiation doses delivered to the trigeminal nerve and the clinical course of patientsmore » treated with and without plugs. Results: We found that blocking increases the length of trigeminal nerve exposed to high-dose radiation, resulting in a significantly higher mean dose to the trigeminal nerve. Significantly more of the patients with blocking achieved excellent pain outcomes (84% vs. 62%), but with higher incidences of moderate and bothersome trigeminal nerve dysfunction (37% mild/10% bothersome with plugs vs. 30% mild/2% bothersome without). Conclusions: The use of plugs to protect the brainstem during GKR treatment for TN increases the dose of irradiation delivered to the intracisternal trigeminal nerve root and is associated with an important increase in the incidence of trigeminal nerve dysfunction. Therefore, beam channel blocking should be avoided for 90 Gy-GKR of TN.« less

  4. GammaKnife surgery: safety and the identity of users.

    PubMed

    Dinka, David; Nyce, James M; Timpka, Toomas

    2005-01-01

    In this study we investigated safety-related usability issues of an advanced medical technology, a radiosurgery system. We were interested in which criteria are important for users when a system's usability and safety is to be improved. The data collection was based on interviews and observations at three different sites where the Leksell GammaKnife is used. The analysis was qualitative. The main finding was that the user's identity or professional background has a significant impact both on how he or she views his or her role in the clinical setting, and on how he or she defines what improvements are necessary and general safety issues. In fact, the opinion even of users experienced in safety-related problems was highly influenced by how they related to the technology and its development. None of the users actually considered Leksell GammaKnife as lacking in safety, instead, their assessment was directed towards potential future system improvements. Our findings suggest that the importance of user identity or professional background cannot be neglected during the development of advanced technology. They also suggest that the user feedback should always be related to user background and identity in order to understand how important different issues are for particular users.

  5. Gamma Knife Radiosurgery Treatment for Metastatic Melanoma of the Trigeminal Nerve and Brainstem: A Case Report and a Review of the Literature

    PubMed Central

    Peterson, Halloran E.; Larson, Erik W.; Fairbanks, Robert K.; Lamoreaux, Wayne T.; Mackay, Alexander R.; Call, Jason A.; Demakas, John J.; Cooke, Barton S.; Lee, Christopher M.

    2013-01-01

    Objective and Importance. Brainstem metastases (BSMs) are uncommon but serious complications of some cancers. They cause significant neurological deficit, and options for treatment are limited. Stereotactic radiosurgery (SRS) has been shown to be a safe and effective treatment for BSMs that prolongs survival and can preserve or in some cases improve neurological function. This case illustrates the use of repeated SRS, specifically Gamma Knife radiosurgery (GKRS) for management of a unique brainstem metastasis. Clinical Presentation. This patient presented 5 years after the removal of a lentigo maligna melanoma from her left cheek with left sided facial numbness and paresthesias with no reported facial weakness. Initial MRI revealed a mass on the left trigeminal nerve that appeared to be a trigeminal schwannoma. Intervention. After only limited response to the first GKRS treatment, a biopsy of the tumor revealed it to be metastatic melanoma, not schwannoma. Over the next two years, the patient would receive 3 more GKRS treatments. These procedures were effective in controlling growth in the treated areas, and the patient has maintained a good quality of life. Conclusion. GKRS has proven in this case to be effective in limiting the growth of this metastatic melanoma without acute adverse effects. PMID:24194991

  6. SU-E-T-563: Multi-Fraction Stereotactic Radiosurgery with Extend System of Gamma Knife: Treatment Verification Using Indigenously Designed Patient Simulating Multipurpose Phantom

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bisht, R; Kale, S; Gopishankar, N

    2015-06-15

    radiosurgery using ES of Gamma knife. The study is a part of intramural research project of Research Section, All India Institute of Medical Sciences New Delhi India (A 247)« less

  7. Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma

    PubMed Central

    Hubbard, Molly; Nordmann, Tyler; Sperduto, Paul W; Clark, H. Brent; Hunt, Matthew A

    2017-01-01

    Learning objectives To evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists. Introduction  Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution. Methods Records from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented.  Results A total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies. Conclusions This data suggests that there is need for

  8. Radiosurgery for epilepsy: Systematic review and International Stereotactic Radiosurgery Society (ISRS) practice guideline.

    PubMed

    McGonigal, Aileen; Sahgal, Arjun; De Salles, Antonio; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Martinez, Roberto; Paddick, Ian; Ryu, Samuel; Slotman, Ben J; Régis, Jean

    2017-11-01

    While there are many reports of radiosurgery for treatment of drug-resistant epilepsy, a literature review is lacking. The aim of this systematic review is to summarize current literature on the use of stereotactic radiosurgery (RS) for treatment of epilepsy. Literature search was performed using various combinations of the search terms "radiosurgery", "stereotactic radiosurgery", "Gamma Knife", "epilepsy" and "seizure", from 1990 until October 2015. Level of evidence was assessed according to the PRISMA guidelines. Fifty-five articles fulfilled inclusion criteria. Level 2 evidence (prospective studies) was available for the clinical indications of mesial temporal lobe epilepsy (MTLE) and hypothalamic hamartoma (HH) treated by Gamma Knife (GK) RS. For remaining indications including corpus callosotomy as palliative treatment, epilepsy related to cavernous malformation and extra-temporal epilepsy, only Level 4 data was available (case report, prospective observational study, or retrospective case series). No Level 1 evidence was available. Based on level 2 evidence, RS is an efficacious treatment to control seizures in MTLE, possibly resulting in superior neuropsychological outcomes and quality of life metrics in selected subjects compared to microsurgery. RS has a better risk-benefit ratio for small hypothalamic hamartomas compared to surgical methods Delayed therapeutic effect resulting in ongoing seizures is associated with morbidity and mortality risk. Lack of level 1 evidence precludes the formation of guidelines at present. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Toxicity of Gamma Knife Radiosurgery in the Treatment of Intracranial Tumors in Patients With Collagen Vascular Diseases or Multiple Sclerosis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lowell, Dot; Tatter, Stephen B.; Bourland, J. Daniel

    Purpose: To assess toxicity in patients with either a collagen vascular disease (CVD) or multiple sclerosis (MS) treated with intracranial radiosurgery. Methods and Materials: Between January 2004 and April 2009, 6 patients with MS and 14 patients with a CVD were treated with Gamma Knife radiosurgery (GKRS) for intracranial tumors. Treated lesions included 15 total brain metastases in 7 patients, 11 benign brain tumors, 1 low grade glioma, and 1 cavernous malformation. Toxicities were graded by the Radiation Therapy Oncology Group Acute/Late Radiation Morbidity Scoring Criteria. 'Rare toxicities' were characterized as those reported in the scientific literature at an incidencemore » of <5%. Results: Median follow-up time was 16 months. Median dose to the tumor margin was 13.0 Gy (range, 12-21 Gy). Median size of tumor was 5.0 cm{sup 3} (range, 0.14-7.8 cm{sup 3}). Of the 14 patients with CVD, none experienced a Grade 3 or 4 toxicity or a toxicity characterized as rare. Of the 6 patients with MS, 3 experienced rare toxicities, and two of these were Grade 3 toxicities. Rare complications included a patient experiencing both communicating hydrocephalus and facial nerve palsy, as well as 2 additional patients with motor cranial nerve palsy. High-grade toxicities included the patient with an acoustic neuroma requiring ventriculoperitoneal shunt placement for obstructive hydrocephalus, and 1 patient with a facial nerve schwannoma who experienced permanent facial nerve palsy. Interval between radiosurgery and high-grade toxicities ranged from 1 week to 4 months. Conclusions: Our series suggests that patients with MS who receive GKRS may be at increased risk of rare and high-grade treatment-related toxicity. Given the time course of toxicity, treatment-related edema or demyelination represent potential mechanisms.« less

  10. Positive clinical effects of gamma knife capsulotomy in a patient with deep brain stimulation-refractory Tourette Syndrome and Obsessive Compulsive Disorder.

    PubMed

    Richieri, Raphaëlle; Blackman, Graham; Musil, Richard; Spatola, Giorgio; Cavanna, Andrea E; Lançon, Christophe; Régis, Jean

    2018-04-26

    We report the first case of a patient with severe, intractable Tourette Syndrome with comorbid Obsessive Compulsive disorder, who recovered from both disorders with gamma-knife (GK) stereotactic radiosurgery following deep brain stimulation (DBS). This case highlights the possible role of the internal capsule within the neural circuitries underlying both TS and OCD, and suggests that in cases of treatment-refractory TS and comorbid OCD, bilateral anterior capsulotomy using stereotactic radiosurgery may be a viable treatment option. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Gamma Knife® radiosurgery for trigeminal neuralgia.

    PubMed

    Yen, Chun-Po; Schlesinger, David; Sheehan, Jason P

    2011-11-01

    Trigeminal neuralgia is characterized by a temporary paroxysmal lancinating facial pain in the trigeminal nerve distribution. The prevalence is four to five per 100,000. Local pressure on nerve fibers from vascular loops results in painful afferent discharge from an injured segment of the fifth cranial nerve. Microvascular decompression addresses the underlying pathophysiology of the disease, making this treatment the gold standard for medically refractory trigeminal neuralgia. In patients who cannot tolerate a surgical procedure, those in whom a vascular etiology cannot be identified, or those unwilling to undergo an open surgery, stereotactic radiosurgery is an appropriate alternative. The majority of patients with typical facial pain will achieve relief following radiosurgical treatment. Long-term follow-up for recurrence as well as for radiation-induced complications is required in all patients undergoing stereotactic radiosurgery for trigeminal neuralgia.

  12. SU-F-J-160: Clinical Evaluation of Targeting Accuracy in Radiosurgery Using Tractography

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Juh, R; Han, J; Kim, C

    Purpose: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgery with Gamma knife. We hypothesized that trigeminal tractography provides more information than 2D-MR imaging, allowing detection of unique, focal changes in the target area after radiosurgery. Methods: Sixteen TN patients (2 females, 4 males, average age 65.3 years) treated with Gamma Knife radiosurgery, 40 Gy/50% isodosemore » line underwent 1.5Tesla MR trigeminal nerve. Target accuracy was assessed from deviation of the coordinates of the target compared with the center of enhancement on post MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated. Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was within 1mm. The radiation doses fitting within the borders of the contrast enhancement the target ranged from 37.5 to 40 Gy. Trigeminal tractography accurately detected the radiosurgical target. Radiosurgery resulted in 47% drop in FA values at the target with no significant change in FA outside the target, suggesting that radiosurgery primarily affects myelin. Tractography was more sensitive, since FA changes were detected regardless of trigeminal nerve enhancement. Conclusion: The median deviation found in clinical assessment of gamma knife treatment for TN Is low and compatible with its high rate of efficiency. DTI parameters accurately detect the effects of focal radiosurgery on the trigeminal nerve, serving as an in vivo imaging tool to study TN. This study is a proof of principle for further assessment of DTI parameters to understand the pathophysiology of TN and

  13. Gamma knife radiosurgery in patients with persistent acromegaly or Cushing's disease: long-term risk of hypopituitarism.

    PubMed

    Cohen-Inbar, Or; Ramesh, Arjun; Xu, Zhiyuan; Vance, Mary Lee; Schlesinger, David; Sheehan, Jason P

    2016-04-01

    For patient with a recurrent or residual acromegaly or Cushing's disease (CD) after resection, gamma knife radiosurgery (GKRS) is often used. Hypopituitarism is the most common adverse effect after GKRS treatment. The paucity of studies with long-term follow-up has hampered understanding of the latent risks of hypopituitarism in patients with acromegaly or CD. We report the long-term risks of hypopituitarism for patients treated with GKRS for acromegaly or CD. From a prospectively created, IRB-approved database, we identified all patients with acromegaly or CD treated with GKRS at the University of Virginia from 1989 to 2008. Only patients with a minimum endocrine follow-up of 60 months were included. The median follow-up is 159·5 months (60·1-278). Thorough radiological and endocrine assessments were performed immediately before GKRS and at regular follow-up intervals. New onset of hypopituitarism was defined as pituitary hormone deficits after GKRS requiring corresponding hormone replacement. Sixty patients with either acromegaly or CD were included. Median tumour volume at time of GKRS was 1·3 cm(3) (0·3-13·4), and median margin dose was 25 Gy (6-30). GKRS-induced new pituitary deficiency occurred in 58·3% (n = 35) of patients. Growth hormone deficiency was most common (28·3%, n = 17). The actuarial overall rates of hypopituitarism at 3, 5 and 10 years were 10%, 21·7% and 53·3%, respectively. The median time to hypopituitarism was 61 months after GKRS (range, 12-160). Cavernous sinus invasion of the tumour was found to correlate with the occurrence of a new or progressive hypopituitarism after GKRS (P = 0·018). Delayed hypopituitarism increases as a function of time after radiosurgery. Hormone axes appear to vary in terms of radiosensitivity. Patients with adenoma in the cavernous sinus are more prone to develop loss of pituitary function after GKRS. © 2015 John Wiley & Sons Ltd.

  14. Local tumour control and eye preservation after gamma-knife radiosurgery of choroidal melanomas.

    PubMed

    Wackernagel, Werner; Holl, Etienne; Tarmann, Lisa; Mayer, Christoph; Avian, Alexander; Schneider, Mona; Kapp, Karin S; Langmann, Gerald

    2014-02-01

    To report on local tumour control and eye preservation after gamma knife radiosurgery (GK-RS) to treat choroidal melanomas. A total of 189 patients with choroidal melanoma were treated with GK-RS, with treatment doses between 25 and 80 Grays. The main outcome measures of our retrospective analysis were local tumour control, time to recurrence, eye retention rate and the reason for and time to secondary enucleation. Patient-associated, tumour-associated and treatment-associated parameters were evaluated as potential risk factors. Local tumour control was achieved in 94.4% of patients. The estimated tumour control rates were 97.6% at 1 year, 94.2% at 5 years and 92.4% at 10 years after treatment. Recurrence was observed between 3.1 months and 60.7 months post-treatment (median: 13.5 months). Advanced tumour stage (Tumour, Node, Metastasis (TNM) 3-4) was the most important risk factor for recurrence (Fine-Gray model; subhazard ratio, SHR: 3.3; p=0.079). The treatment dose was not related to tumour recurrence. The eye preservation rate was 81.6% at 5 years after treatment, remaining stable thereafter. Twenty-five eyes (14.1%) had to be enucleated at between 17 days and 68.0 months (median: 13.9 months) after GK-RS, and advanced tumour stage (Cox model; p=0.005), treatment dose (p=0.048), pretreatment visual acuity (p=0.016), and retinal detachment (p=0.027) were risk factors for requiring enucleation. GK-RS achieved a high tumour control rate, comparable to linear accelerator-based radiotherapy. Advanced TNM stage was a predictive risk factor for tumour recurrence and for secondary enucleation after GK-RS. Lower treatment doses were unrelated to tumour recurrence, although they were associated with an improved eye retention rate.

  15. SU-E-J-34: Clinical Evaluation of Targeting Accuracy and Tractogrphy Delineation of Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Juh, R; Suh, T; Kim, Y

    2014-06-01

    Purpose: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. The efficiency of radiosurgery is related to its highly precise targeting. We assessed clinically the targeting accuracy of radiosurgery with Gamma knife. We hypothesized that trigeminal tractography provides more information than 2D-MR imaging, allowing detection of unique, focal changes in the target area after radiosurgery. Methods: Sixteen TN patients (2 females, 4 male, average age 65.3 years) treated with Gamma Knife radiosurgery, 40 Gy/50% isodosemore » line underwent 1.5Tesla MR trigeminal nerve . Target accuracy was assessed from deviation of the coordinates of the target compared with the center of enhancement on post MRI. Radiation dose delivered at the borders of contrast enhancement was evaluated Results: The median deviation of the coordinates between the intended target and the center of contrast enhancement was within 1mm. The radiation doses fitting within the borders of the contrast enhancement the target ranged from 37.5 to 40 Gy. Trigeminal tractography accurately detected the radiosurgical target. Radiosurgery resulted in 47% drop in FA values at the target with no significant change in FA outside the target, suggesting that radiosurgery primarily affects myelin. Tractography was more sensitive, since FA changes were detected regardless of trigeminal nerve enhancement Conclusion: The median deviation found in clinical assessment of gamma knife treatment for TN Is low and compatible with its high rate of efficiency. DTI parameters accurately detect the effects of focal radiosurgery on the trigeminal nerve, serving as an in vivo imaging tool to study TN. This study is a proof of principle for further assessment of DTI parameters to understand the pathophysiology of TN and treatment

  16. Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Massager, Nicolas, E-mail: nmassage@ulb.ac.be; Neurosurgery-Department, Hospital Erasme, Brussels; Lonneville, Sarah

    2011-11-15

    Objectives: We investigated variations in the distribution of radiation dose inside (dose inhomogeneity) and outside (dose falloff) the target volume during Gamma Knife (GK) irradiation of vestibular schwannoma (VS). We analyzed the relationship between some parameters of dose distribution and the clinical and radiological outcome of patients. Methods and Materials: Data from dose plans of 203 patients treated for a vestibular schwannoma by GK C using same prescription dose (12 Gy at the 50% isodose) were collected. Four different dosimetric indexes were defined and calculated retrospectively in all plannings on the basis of dose-volume histograms: Paddick conformity index (PI), gradientmore » index (GI), homogeneity index (HI), and unit isocenter (UI). The different measures related to distribution of the radiation dose were compared with hearing and tumor outcome of 203 patients with clinical and radiological follow-up of minimum 2 years. Results: Mean, median, SD, and ranges of the four indexes of dose distribution analyzed were calculated; large variations were found between dose plans. We found a high correlation between the target volume and PI, GI, and UI. No significant association was found between the indexes of dose distribution calculated in this study and tumor control, tumor volume shrinkage, hearing worsening, loss of functional hearing, or complete hearing loss at last follow-up. Conclusions: Parameters of distribution of the radiation dose during GK radiosurgery for VS can be highly variable between dose plans. The tumor and hearing outcome of patients treated is not significantly related to these global indexes of dose distribution inside and around target volume. In GK radiosurgery for VS, the outcome seems more to be influenced by local radiation dose delivered to specific structures or volumes than by global dose gradients.« less

  17. Gamma Knife radiosurgery for brain metastases from pulmonary large cell neuroendocrine carcinoma: a Japanese multi-institutional cooperative study (JLGK1401).

    PubMed

    Kawabe, Takuya; Yamamoto, Masaaki; Sato, Yasunori; Yomo, Shoji; Kondoh, Takeshi; Nagano, Osamu; Serizawa, Toru; Tsugawa, Takahiko; Okamoto, Hisayo; Akabane, Atsuya; Aita, Kazuyasu; Sato, Manabu; Jokura, Hidefumi; Kawagishi, Jun; Shuto, Takashi; Kawai, Hideya; Moriki, Akihito; Kenai, Hiroyuki; Iwai, Yoshiyasu; Gondo, Masazumi; Hasegawa, Toshinori; Yasuda, Soichiro; Kikuchi, Yasuhiro; Nagatomo, Yasushi; Watanabe, Shinya; Hashimoto, Naoya

    2016-12-01

    OBJECTIVE In 1999, the World Health Organization categorized large cell neuroendocrine carcinoma (LCNEC) of the lung as a variant of large cell carcinoma, and LCNEC now accounts for 3% of all lung cancers. Although LCNEC is categorized among the non-small cell lung cancers, its biological behavior has recently been suggested to be very similar to that of a small cell pulmonary malignancy. The clinical outcome for patients with LCNEC is generally poor, and the optimal treatment for this malignancy has not yet been established. Little information is available regarding management of LCNEC patients with brain metastases (METs). This study aimed to evaluate the efficacy of Gamma Knife radiosurgery (GKRS) for patients with brain METs from LCNEC. METHODS The Japanese Leksell Gamma Knife Society planned this retrospective study in which 21 Gamma Knife centers in Japan participated. Data from 101 patients were reviewed for this study. Most of the patients with LCNEC were men (80%), and the mean age was 67 years (range 39-84 years). Primary lung tumors were reported as well controlled in one-third of the patients. More than half of the patients had extracranial METs. Brain metastasis and lung cancer had been detected simultaneously in 25% of the patients. Before GKRS, brain METs had manifested with neurological symptoms in 37 patients. Additionally, prior to GKRS, resection was performed in 17 patients and radiation therapy in 10. A small cell lung carcinoma-based chemotherapy regimen was chosen for 48 patients. The median lesion number was 3 (range 1-33). The median cumulative tumor volume was 3.5 cm 3 , and the median radiation dose was 20.0 Gy. For statistical analysis, the standard Kaplan-Meier method was used to determine post-GKRS survival. Competing risk analysis was applied to estimate GKRS cumulative incidences of maintenance of neurological function and death, local recurrence, appearance of new lesions, and complications. RESULTS The overall median survival time

  18. Gamma Knife radiosurgery for vestibular schwannoma: clinical results at long-term follow-up in a series of 379 patients.

    PubMed

    Boari, Nicola; Bailo, Michele; Gagliardi, Filippo; Franzin, Alberto; Gemma, Marco; del Vecchio, Antonella; Bolognesi, Angelo; Picozzi, Piero; Mortini, Pietro

    2014-12-01

    Since the 1990 s, Gamma Knife radiosurgery (GKRS) has become the first-line treatment option for small- to medium-size vestibular schwannomas (VSs), especially in patients without mass effect-related symptoms and with functional hearing. The aim of this study was to assess the safety and efficacy of GKRS, in terms of tumor control, hearing preservation, and complications, in a series of 379 consecutive patients treated for VS. Of 523 patients treated at the authors' institution for VS between 2001 and 2010, the authors included 379 who underwent GKRS as the primary treatment. These patients were not affected by Type 2 neurofibromatosis and had clinical follow-up of at least 36 months. Clinical follow-up (mean and median 75.7 and 69.5 months, respectively) was performed for all patients, whereas audiometric and quantitative radiological follow-up examinations were obtained for only 153 and 219 patients, respectively. The patients' ages ranged from 23 to 85 years (mean 59 years). The mean tumor volume was 1.94 ± 2.2 cm(3) (median 1.2 cm(3), range 0.013-14.3 cm(3)), and the median margin dose was 13 Gy (range 11-15 Gy). Parameters considered as determinants of the clinical outcome were long-term tumor control, hearing preservation, and complications. A statistical analysis was performed to correlate clinical outcomes with the radiological features of the tumor, dose-planning parameters, and patient characteristics. Control of the tumor with GKRS was achieved in 97.1% of the patients. In 82.7% of the patients, the tumor volume had decreased at the last follow-up, with a mean relative reduction of 34.1%. The rate of complications was very low, with most consisting of a transient worsening of preexisting symptoms. Patients who had vertigo, balance disorders, or facial or trigeminal impairment usually experienced a complete or at least significant symptom relief after treatment. However, no significant improvement was observed in patients previously reporting tinnitus

  19. Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter.

    PubMed

    Huang, Cheng-Wei; Tu, Hsien-Tang; Chuang, Chun-Yi; Chang, Cheng-Siu; Chou, Hsi-Hsien; Lee, Ming-Tsung; Huang, Chuan-Fu

    2018-05-01

    OBJECTIVE Stereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs. METHODS Between 2000 and 2014, 35 patients with large VSs, defined as having both a single dimension > 3 cm and a volume > 10 cm 3 , underwent Gamma Knife radiosurgery (GKRS). Nine patients (25.7%) had previously undergone resection. The median total volume covered in this group of patients was 14.8 cm 3 (range 10.3-24.5 cm 3 ). The median tumor margin dose was 11 Gy (range 10-12 Gy). RESULTS The median follow-up duration was 48 months (range 6-156 months). All 35 patients had regular MRI follow-up examinations. Twenty tumors (57.1%) had a volume reduction of greater than 50%, 5 (14.3%) had a volume reduction of 15%-50%, 5 (14.3%) were stable in size (volume change < 15%), and 5 (14.3%) had larger volumes (all of these lesions were eventually resected). Four patients (11.4%) underwent resection within 9 months to 6 years because of progressive symptoms. One patient (2.9%) had open surgery for new-onset intractable trigeminal neuralgia at 48 months after GKRS. Two patients (5.7%) who developed a symptomatic cyst underwent placement of a cystoperitoneal shunt. Eight (66%) of 12 patients with pre-GKRS trigeminal sensory dysfunction had hypoesthesia relief. One hemifacial spasm completely resolved 3 years after treatment. Seven patients with facial weakness experienced no deterioration after GKRS. Two of 3 patients with serviceable hearing before GKRS deteriorated while 1 patient retained the same level of hearing. Two patients improved from severe hearing loss to pure tone audiometry less than 50 dB. The authors found borderline statistical significance for post-GKRS tumor enlargement for later resection (p = 0.05, HR 9.97, CI 0

  20. Utilization of Cone-Beam Computed Tomographic Angiography in Planning for Gamma Knife Radiosurgery of Arteriovenous Malformations: A Case Series and Early Report

    PubMed Central

    Safain, Mina G.; Rahal, Jason P.; Raval, Ami; Rivard, Mark J.; Mignano, John; Wu, Julian; Malek, Adel M.

    2014-01-01

    Background The effectiveness of Gamma Knife radiosurgery (GKR) for cerebral arteriovenous malformations (AVM) is predicated on inclusion of the entire nidus while excluding normal tissue. As such, GKR may be limited by the resolution and accuracy of the imaging modality used in targeting. Objective We present the first case series to demonstrate the feasibility of utilizing ultra-high-resolution C-arm cone beam computed tomography angiography (CBCT-A) in AVM targeting. Methods From June 2009 to June 2013, CBCT-A was utilized for targeting of all patients with AVMs treated with GKR at our institution. Patients underwent Leksell stereotactic head frame placement followed by catheter-based biplane 2-D digital subtraction angiography (DSA), 3-D rotational angiography (3DRA), as well as CBCT-A. The CBCT-A dataset was used for stereotactic planning for GKR. Patients were followed up at 1, 3, 6, and 12 months, and then annually thereafter. Results CBCT-A-based targeting was used in twenty-two consecutive patients. CBCT-A provided detailed spatial resolution and sensitivity of nidal angioarchitecture enabling treatment. The average radiation dose to the margin of the AVM nidus corresponding to the 50% percent isodose line was 15.6 Gy. No patient had treatment-associated hemorrhage. At early follow-up (mean=16 months), 84% of patients had a decreasing or obliterated AVM nidus. Conclusion CBCT-A-guided radiosurgery is feasible and useful because it provides sufficient detailed resolution and sensitivity for imaging brain AVMs. PMID:24584136

  1. A minimally invasive treatment option for large metastatic brain tumors: long-term results of two-session Gamma Knife stereotactic radiosurgery

    PubMed Central

    2014-01-01

    Background Large brain metastases (BM) remain a significant cause of morbidity and death for cancer patients despite current advances in multimodality therapies. The goal of the present study was to evaluate the efficacy and limitations of 2-session Gamma Knife stereotactic radiosurgery (SRS) for patients with large BM. Methods This is a prospective, open-label and single arm study analyzing 58 consecutive patients who received 2-session SRS for large BM (≥ 10 mL). The median age was 66 years, and the median Karnofsky performance status (KPS) score was 70. SRS was the initial treatment in 51 large tumors (84%) and was used as salvage after failed prior treatments for 10 tumors (16%). The fraction protocol was 20-30 Gy given in 2 fractions with 3–4 weeks between fractions. Overall survival (OS) and neurological death (ND), local tumor control and KPS were analyzed. Results The median follow-up time was 9.0 months. One- and 2-year OS rates were 47% and 20%, respectively. The median OS time was 11.8 months (95% CI: 5.5-15.6). The causes of death were intracranial local progression in 5 cases, meningeal carcinomatosis in 3 and progression of the primary lesion in 39. One- and 2-year ND-free survival rates were 91% and 84%, respectively. In 52 of 61 large BM (85%) with sufficient radiological follow-up data, 6- and 12-month local tumor control rates were 85% and 64%, respectively. The mean KPS improved from 70 at the 1st SRS to 82 at the 2nd; the first follow-up mean KPS was 87 (P < 0.001). Symptomatic radiation injury developed and required conservative treatment in 3 patients (5%). Conclusions Long-term follow-up showed that two-session Gamma Knife SRS achieved durable tumor control rates as well as acceptable treatment-related morbidity. This treatment method may potentially merit being offered to patients with large BM who are in poor condition or are otherwise ineligible for standard care. PMID:24917309

  2. CyberKnife frameless single-fraction stereotactic radiosurgery for tumors of the sacrum.

    PubMed

    Gerszten, Peter C; Ozhasoglu, Cihat; Burton, Steven A; Welch, William C; Vogel, William J; Atkins, Barbara A; Kalnicki, Shalom

    2003-08-15

    The role of stereotactic radiosurgery for the treatment of intracranial lesions is well established. The experience with radiosurgery for the treatment of spinal and sacral lesions is more limited. Sacral lesions should be amenable to radiosurgical treatment similar to that used for their intracranial counterparts. The authors evaluated a single- fraction radiosurgical technique performed using the CyberKnife Real-Time Image-Guided Radiosurgery System for the treatment of the sacral lesion. The CyberKnife is a frameless radiosurgery system based on the coupling of an orthogonal pair of x-ray cameras to a dynamically manipulated robot-mounted linear accelerator possessing six degrees of freedom, which guides the therapy beam to the intended target without the need for frame-based fixation. All sacral lesions were located and tracked for radiation delivery relative to fiducial bone markers placed percutaneously. Eighteen patients were treated with single-fraction radiosurgery. Tumor histology included one benign and 17 malignant tumors. Dose plans were calculated based on computerized tomography scans acquired using 1.25-mm slices. Planning treatment volume was defined as the radiographically documented tumor volume with no margin. Tumor dose was maintained at 12 to 20 Gy to the 80% isodose line (mean 15 Gy). Tumor volume ranged from 23.6 to 187.4 ml (mean 90 ml). The volume of the cauda equina receiving greater than 8 Gy ranged from 0 to 1 ml (mean 0.1 ml). All patients underwent the procedure in an outpatient setting. No acute radiation toxicity or new neurological deficits occurred during the mean follow-up period of 6 months. Pain improved in all 13 patients who were symptomatic prior to treatment. No tumor progression has been documented on follow-up imaging. Stereotactic radiosurgery was found to be feasible, safe, and effective for the treatment of both benign and malignant sacral lesions. The major potential benefits of radiosurgical ablation of sacral

  3. Technical Note: PRESAGE three-dimensional dosimetry accurately measures Gamma Knife output factors

    PubMed Central

    Klawikowski, Slade J.; Yang, James N.; Adamovics, John; Ibbott, Geoffrey S.

    2014-01-01

    Small-field output factor measurements are traditionally very difficult because of steep dose gradients, loss of lateral electronic equilibrium, and dose volume averaging in finitely sized detectors. Three-dimensional (3D) dosimetry is ideal for measuring small output factors and avoids many of these potential challenges of point and two-dimensional detectors. PRESAGE 3D polymer dosimeters were used to measure the output factors for the 4 mm and 8 mm collimators of the Leksell Perfexion Gamma Knife radiosurgery treatment system. Discrepancies between the planned and measured distance between shot centers were also investigated. A Gamma Knife head frame was mounted onto an anthropomorphic head phantom. Special inserts were machined to hold 60 mm diameter, 70 mm tall cylindrical PRESAGE dosimeters. The phantom was irradiated with one 16 mm shot and either one 4 mm or one 8 mm shot, to a prescribed dose of either 3 Gy or 4 Gy to the 50% isodose line. The two shots were spaced between 30 mm and 60 mm apart and aligned along the central axis of the cylinder. The Presage dosimeters were measured using the DMOS-RPC optical CT scanning system. Five independent 4 mm output factor measurements fell within 2% of the manufacturer’s Monte Carlo simulation-derived nominal value, as did two independent 8 mm output factor measurements. The measured distances between shot centers varied by ± 0.8 mm with respect to the planned shot displacements. On the basis of these results, we conclude that PRESAGE dosimetry is excellently suited to quantify the difficult-to-measure Gamma Knife output factors. PMID:25368961

  4. Gamma Knife radiosurgery for treatment of growing vestibular schwannomas in patients with neurofibromatosis Type 2: a matched cohort study with sporadic vestibular schwannomas.

    PubMed

    Kruyt, Ivo J; Verheul, Jeroen B; Hanssens, Patrick E J; Kunst, Henricus P M

    2018-01-01

    OBJECTIVE Neurofibromatosis Type 2 (NF2) is a tumor syndrome characterized by an autosomal dominant pattern of inheritance. The hallmark of NF2 is the development of bilateral vestibular schwannomas (VSs), generally by 30 years of age. One of the first-line treatment options for small to medium-large VSs is radiosurgery. Although radiosurgery shows excellent results in sporadic VS, its use in NF2-related VS is still a topic of dispute. The aim of this study was to evaluate long-term tumor control, hearing preservation rates, and factors influencing outcome of optimally dosed, contemporary Gamma Knife radiosurgery (GKRS) for growing VSs in patients with NF2 and compare the findings to data obtained in patients with sporadic VS also treated by means of GKRS. METHODS The authors performed a retrospective analysis of 47 growing VSs in 34 NF2 patients who underwent GKRS treatment performed with either the Model C or Perfexion Leksell Gamma Knife, with a median margin dose of 11 Gy. Actuarial tumor control rates were estimated using the Kaplan-Meier method. For patient- and treatment-related factors, a Cox proportional hazards model was used to identify predictors of outcome. Trigeminal, facial, and vestibulocochlear nerve function were assessed before and after treatment. NF2-related VS patients were matched 1:1 with sporadic VS patients who were treated in the same institute, and the same indications for treatment, definitions, and dosimetry were used in order to compare outcomes. RESULTS Actuarial tumor control rates in NF2 patients after 1, 3, 5, and 8 years were 98%, 89%, 87%, and 87%, respectively. Phenotype and tumor volume had significant hazard rates of 0.086 and 22.99, respectively, showing that Feiling-Gardner phenotype and a tumor volume not exceeding 6 cm 3 both were associated with significantly better outcome. Actuarial rates of serviceable hearing preservation after 1, 3, 5, and 7 years were 95%, 82%, 59%, and 33%, respectively. None of the patients

  5. The value of image coregistration during stereotactic radiosurgery.

    PubMed

    Koga, T; Maruyama, K; Igaki, H; Tago, M; Saito, N

    2009-05-01

    Coregistration of any neuroimaging studies into treatment planning for stereotactic radiosurgery became easily applicable using the Leksell Gamma Knife 4C, a new model of gamma knife. The authors investigated the advantage of this image processing. Since installation of the Leksell Gamma Knife 4C at the authors' institute, 180 sessions of radiosurgery were performed. Before completion of planning, coregistration of frameless images of other modalities or previous images was considered to refine planning. Treatment parameters were compared for planning before and after refinement by use of coregistered images. Coregistered computed tomography clarified the anatomical structures indistinct on magnetic resonance imaging. Positron emission tomography visualized lesions disclosing metabolically high activity. Coregistration of prior imaging distinguished progressing lesions from stable ones. Diffusion-tensor tractography was integrated for lesions adjacent to the corticospinal tract or the optic radiation. After refinement of planning in 36 sessions, excess treated volume decreased (p = 0.0062) and Paddick conformity index improved (p < 0.001). Maximal dose to the white matter tracts was decreased (p < 0.001). Image coregistration provided direct information on anatomy, metabolic activity, chronological changes, and adjacent critical structures. This gathered information was sufficiently informative during treatment planning to supplement ambiguous information on stereotactic images, and was useful especially in reducing irradiation to surrounding normal structures.

  6. A nomogram for predicting distant brain failure in patients treated with gamma knife stereotactic radiosurgery without whole brain radiotherapy

    PubMed Central

    Ayala-Peacock, Diandra N.; Peiffer, Ann M.; Lucas, John T.; Isom, Scott; Kuremsky, J. Griff; Urbanic, James J.; Bourland, J. Daniel; Laxton, Adrian W.; Tatter, Stephen B.; Shaw, Edward G.; Chan, Michael D.

    2014-01-01

    Background We review our single institution experience to determine predictive factors for early and delayed distant brain failure (DBF) after radiosurgery without whole brain radiotherapy (WBRT) for brain metastases. Materials and methods Between January 2000 and December 2010, a total of 464 patients were treated with Gamma Knife stereotactic radiosurgery (SRS) without WBRT for primary management of newly diagnosed brain metastases. Histology, systemic disease, RPA class, and number of metastases were evaluated as possible predictors of DBF rate. DBF rates were determined by serial MRI. Kaplan–Meier method was used to estimate rate of DBF. Multivariate analysis was performed using Cox Proportional Hazard regression. Results Median number of lesions treated was 1 (range 1–13). Median time to DBF was 4.9 months. Twenty-seven percent of patients ultimately required WBRT with median time to WBRT of 5.6 months. Progressive systemic disease (χ2= 16.748, P < .001), number of metastases at SRS (χ2 = 27.216, P < .001), discovery of new metastases at time of SRS (χ2 = 9.197, P < .01), and histology (χ2 = 12.819, P < .07) were factors that predicted for earlier time to distant failure. High risk histologic subtypes (melanoma, her2 negative breast, χ2 = 11.020, P < .001) and low risk subtypes (her2 + breast, χ2 = 11.343, P < .001) were identified. Progressive systemic disease (χ2 = 9.549, P < .01), number of brain metastases (χ2 = 16.953, P < .001), minimum SRS dose (χ2 = 21.609, P < .001), and widespread metastatic disease (χ2 = 29.396, P < .001) were predictive of shorter time to WBRT. Conclusion Systemic disease, number of metastases, and histology are factors that predict distant failure rate after primary radiosurgical management of brain metastases. PMID:24558022

  7. Gamma Knife Radiosurgery for Treatment of Cerebral Metastases From Non-Small-Cell Lung Cancer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Motta, Micaela, E-mail: motta.micaela@hsr.it; Vecchio, Antonella del; Attuati, Luca

    2011-11-15

    Purpose: To evaluate clinical and physico-dosimetric variables affecting clinical outcome of patients treated with Gamma Knife radiosurgery (GKRS) for brain metastases from non-small cell lung cancer (NSCLC). Methods and Materials: Between 2001 and 2006, 373 patients (298 men and 75 women, median age 65 years) with brain metastases from NSCLC underwent GKRS. All of them had KPS {>=} 60%, eight or fewer brain metastases, confirmed histopathological diagnosis and recent work-up (<3 months). Thirty-five patients belonged to recursive partitioning analysis (RPA) Class I, 307 patients were in RPA Class II, 7 patients were in RPA Class III. Median tumor volume wasmore » 3.6 cm{sup 3}. Median marginal dose was 22.5 Gy at 50% isodose.; median 10 Gy and 12 Gy isodose volumes were 30.8 cm{sup 3} and 15.8 cm{sup 3}, respectively. Follow-up with MRI was performed every 3 months. Overall survival data were collected from internal database, telephone interviews, and identifying registries. Results: Mean follow-up after GKRS was 51 months (range, 6 to 96 months); mean overall survival was 14.2 months. Of 373 patients, 29 were alive at time of writing, 104 had died of cerebral progression, and 176 had died of systemic progression. In 64 cases it was not possible to ascertain the cause. Univariate and multivariate analysis were adjusted for the following: RPA class, surgery, WBRT, age, gender, number of lesions, median tumor volume, median peripheral dose, and 10 Gy and 12 Gy volumes. Identified RPA class and overall tumor volume >5 cc were the only two covariates independently predictive of overall survival in patients who died of cerebral progression. Conclusions: Global volume of brain disease should be the main parameter to consider for performing GKRS, which is a first-line therapy for patient in good general condition and controlled systemic disease.« less

  8. Long-Term Survival in a Patient with Multiple Brain Metastases from Small-Cell Lung Cancer Treated with Gamma Knife Radiosurgery on Four Occasions: A Case Report

    PubMed Central

    Elaimy, Ameer L.; Thumma, Sudheer R.; Lamm, Andrew F.; Mackay, Alexander R.; Lamoreaux, Wayne T.; Fairbanks, Robert K.; Demakas, John J.; Cooke, Barton S.; Lee, Christopher M.

    2012-01-01

    Brain metastases are the most common cancerous neoplasm in the brain. The treatment of these lesions is challenging and often includes a multimodality management approach with whole-brain radiation therapy, stereotactic radiosurgery, and neurosurgery options. Although advances in biomedical imaging technologies and the treatment of extracranial cancer have led to the overall increase in the survival of brain metastases patients, the finding that select patients survive several years remains puzzling. For this reason, we present the case of a 70-year-old patient who was diagnosed with multiple brain metastases from small-cell lung cancer five years ago and is currently alive following treatment with chemotherapy for the primary cancer and whole-brain radiation therapy and Gamma Knife radiosurgery on four separate occasions for the neurological cancer. Since the diagnosis of brain metastases five years ago, the patient's primary cancer has remained controlled. Furthermore, multiple repeat GKRS procedures provided this patient with high levels of local tumor control, which in combination with a stable primary cancer led to an extended period of survival and a highly functional life. Further analysis and clinical research will be valuable in assessing the durability of multiple GKRS for brain metastases patients who experience long-term survival. PMID:23091748

  9. Long-term outcome of gamma knife radiosurgery for metastatic brain tumors originating from lung cancer

    PubMed Central

    Bir, Shyamal C.; Ambekar, Sudheer; Bollam, Papireddy; Nanda, Anil

    2014-01-01

    Background: Gamma knife radiosurgery (GKRS) has emerged as an important treatment option for metastasis brain tumors (MBTs). However, the long-term outcome of GKRS on MBTs originating from lung carcinoma is not well understood. The treatment of MBTs derived from lung cancer with GKRS at our institution is reviewed. Methods: We performed a retrospective review (2000-2013) of 173 patients with MBTs from lung cancer who received GKRS. Out of 173 patients, 38 patients had recurrent tumors after microsurgical resection and whole brain radiotherapy (WBT). Results: GKRS in MBTs metastasized from lung carcinoma showed significant variations in tumor growth control (decreased in 79 [45.7%] patients, arrested growth in 54 [31.2%] patients, and increased tumor size in 40 [23.1%] patients). The median survival in the study population was 14 months. Overall survival after 3 years was 25%, whereas progression-free survival after 3 years was 45%. The predictive factors for improving survival in the patients with MBTs were recursive partitioning analysis (RPA) class I (P = 0.005), absence of hydrocephalus (P = 0.001), Karnofsky performance scale (KPS) >70 (P = 0.007), age ≤65 (P = 0.041), tumor size ≤3 cm (P = 0.023), controlled primary tumor (P = 0.049), and single number of MBTS (P = 0.044). Conclusion: Long-term follow-up revealed that GKRS offers a high rate of tumor control and good overall survival period in both new and recurrent patients with MBTs originating from lung carcinoma. Thus, GKRS is an effective treatment option for new patients with MBTs from lung cancer, as well as an adjuvant therapy in patients with recurrent MBTs derived from lung cancer. PMID:25289169

  10. Analysis of risk factors to predict communicating hydrocephalus following gamma knife radiosurgery for intracranial schwannoma.

    PubMed

    Lee, Seunghoon; Seo, Seong-Wook; Hwang, Juyoung; Seol, Ho Jun; Nam, Do-Hyun; Lee, Jung-Il; Kong, Doo-Sik

    2016-12-01

    Communicating hydrocephalus (HCP) in vestibular schwannomas (VS) after gamma knife radiosurgery (GKRS) has been reported in the literature. However, little information about its incidence and risk factors after GKRS for intracranial schwannomas is yet available. The objective of this study was to identify the incidence and risk factors for developing communicating HCP after GKRS for intracranial schwannomas. We retrospectively reviewed a total of 702 patients with intracranial schwannomas who were treated with GKRS between January 2002 and December 2015. We investigated patients' age, gender, tumor origin, previous surgery history, tumor volume, marginal radiation dose, and presence of tumor control to identify associations with communicating HCP following GKRS. To make predictive models of communicating HCP, we performed Cox regression analyses and constructed a decision tree for risk factors. In total, 29 of the 702 patients (4.1%) developed communicating HCP following GKRS, which required ventriculo-peritoneal (VP) shunt surgery. Multivariate analyses indicated that age (P = 0.0011), tumor origin (P = 0.0438), and tumor volume (P < 0.0001) were significant predictors of communicating HCP in patients with intracranial schwannoma after GKRS. Using machine-learning methods, we fit an optimal predictive model. We found that developing communicating HCP following GKRS was most likely if the tumor was vestibular origin and had a volume ≥13.65 cm 3 . Communicating HCP is not a rare complication of GKRS for intracranial schwannomas. Under specific conditions, communicating HCP following GKRS is warranted for this patient group, and this patient group should be closely followed up. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  11. Conservative management or gamma knife radiosurgery for vestibular schwannoma: tumor growth, symptoms, and quality of life.

    PubMed

    Breivik, Cathrine Nansdal; Nilsen, Roy Miodini; Myrseth, Erling; Pedersen, Paal Henning; Varughese, Jobin K; Chaudhry, Aqeel Asghar; Lund-Johansen, Morten

    2013-07-01

    There are few reports about the course of vestibular schwannoma (VS) patients following gamma knife radiosurgery (GKRS) compared with the course following conservative management (CM). In this study, we present prospectively collected data of 237 patients with unilateral VS extending outside the internal acoustic canal who received either GKRS (113) or CM (124). The aim was to measure the effect of GKRS compared with the natural course on tumor growth rate and hearing loss. Secondary end points were postinclusion additional treatment, quality of life (QoL), and symptom development. The patients underwent magnetic resonance imaging scans, clinical examination, and QoL assessment by SF-36 questionnaire. Statistics were performed by using Spearman correlation coefficient, Kaplan-Meier plot, Poisson regression model, mixed linear regression models, and mixed logistic regression models. Mean follow-up time was 55.0 months (26.1 standard deviation, range 10-132). Thirteen patients were lost to follow-up. Serviceable hearing was lost in 54 of 71 (76%) (CM) and 34 of 53 (64%) (GKRS) patients during the study period (not significant, log-rank test). There was a significant reduction in tumor volume over time in the GKRS group. The need for treatment following initial GKRS or CM differed at highly significant levels (log-rank test, P < .001). Symptom and QoL development did not differ significantly between the groups. In VS patients, GKRS reduces the tumor growth rate and thereby the incidence rate of new treatment about tenfold. Hearing is lost at similar rates in both groups. Symptoms and QoL seem not to be significantly affected by GKRS.

  12. Neurological Change after Gamma Knife Radiosurgery for Brain Metastases Involving the Motor Cortex

    PubMed Central

    Park, Chang-Yong; Choi, Hyun-Yong; Lee, Sang-Ryul; Roh, Tae Hoon; Seo, Mi-Ra

    2016-01-01

    Background Although Gamma Knife radiosurgery (GKRS) can provide beneficial therapeutic effects for patients with brain metastases, lesions involving the eloquent areas carry a higher risk of neurologic deterioration after treatment, compared to those located in the non-eloquent areas. We aimed to investigate neurological change of the patients with brain metastases involving the motor cortex (MC) and the relevant factors related to neurological deterioration after GKRS. Methods We retrospectively reviewed clinical, radiological and dosimetry data of 51 patients who underwent GKRS for 60 brain metastases involving the MC. Prior to GKRS, motor deficits existed in 26 patients (50.9%). The mean target volume was 3.2 cc (range 0.001–14.1) at the time of GKRS, and the mean prescription dose was 18.6 Gy (range 12–24 Gy). Results The actuarial median survival time from GKRS was 19.2±5.0 months. The calculated local tumor control rates at 6 and 12 months after GKRS were 89.7% and 77.4%, respectively. During the median clinical follow-up duration of 12.3±2.6 months (range 1–54 months), 18 patients (35.3%) experienced new or worsened neurologic deficits with a median onset time of 2.5±0.5 months (range 0.3–9.7 months) after GKRS. Among various factors, prescription dose (>20 Gy) was a significant factor for the new or worsened neurologic deficits in univariate (p=0.027) and multivariate (p=0.034) analysis. The managements of 18 patients were steroid medication (n=10), boost radiation therapy (n=5), and surgery (n=3), and neurological improvement was achieved in 9 (50.0%). Conclusion In our series, prescription dose (>20 Gy) was significantly related to neurological deterioration after GKRS for brain metastases involving the MC. Therefore, we suggest that careful dose adjustment would be required for lesions involving the MC to avoid neurological deterioration requiring additional treatment in the patients with limited life expectancy. PMID:27867921

  13. Gamma-knife radiosurgery in acromegaly: a 4-year follow-up study.

    PubMed

    Attanasio, Roberto; Epaminonda, Paolo; Motti, Enrico; Giugni, Enrico; Ventrella, Laura; Cozzi, Renato; Farabola, Mario; Loli, Paola; Beck-Peccoz, Paolo; Arosio, Maura

    2003-07-01

    Stereotactic radiosurgery by gamma-knife (GK) is an attractive therapeutic option after failure of microsurgical removal in patients with pituitary adenoma. In these tumors or remnants of them, it aims to obtain the arrest of cell proliferation and hormone hypersecretion using a single precise high dose of ionizing radiation, sparing surrounding structures. The long-term efficacy and toxicity of GK in acromegaly are only partially known. Thirty acromegalic patients (14 women and 16 men) entered a prospective study of GK treatment. Most were surgical failures, whereas in 3 GK was the primary treatment. Imaging of the adenoma and target coordinates identification were obtained by high resolution magnetic resonance imaging. All patients were treated with multiple isocenters (mean, 8; range, 3-11). The 50% isodose was used in 27 patients (90%). The mean margin dose was 20 Gy (range, 15-35), and the dose to the visual pathways was always less than 8 Gy. After a median follow-up of 46 months (range, 9-96), IGF-I fell from 805 micro g/liter (median; interquartile range, 640-994) to 460 micro g/liter (interquartile range, 217-654; P = 0.0002), and normal age-matched IGF-I levels were reached in 7 patients (23%). Mean GH levels decreased from 10 micro g/liter (interquartile range, 6.4-15) to 2.9 micro g/liter (interquartile range, 2-5.3; P < 0.0001), reaching levels below 2.5 micro g/liter in 11 (37%). The rate of persistently pathological hormonal levels was still 70% at 5 yr by Kaplan-Meier analysis. The median volume was 1.43 ml (range, 0.20-3.7). Tumor shrinkage (at least 25% of basal volume) occurred after 24 months (range, 12-36) in 11 of 19 patients (58% of assessable patients). The rate of shrinkage was 79% at 4 yr. In no case was further growth observed. Only 1 patient complained of side-effects (severe headache and nausea immediately after the procedure, with full recovery in a few days with steroid therapy). Anterior pituitary failures were observed in 2 patients

  14. The history of stereotactic radiosurgery and radiotherapy.

    PubMed

    Lasak, John M; Gorecki, John P

    2009-08-01

    Stereotactic neurosurgery originated from the pioneering work of Horsley and Clarke, who developed a stereotactic apparatus to study the monkey brain in 1908. Spiegel and Wycis applied this technology to the human brain in 1947, which ultimately lead to the development of multiple stereotactic neurosurgical devices during the 1950s. It was Lars Leksell of Sweden, however, who envisioned stereotactic radiosurgery. Leksell developed the gamma knife to treat intracranial lesions in a noninvasive fashion. His work stimulated worldwide interest and created the field of stereotactic radiosurgery.

  15. Cavernomas: Outcomes after gamma-knife radiosurgery in Iran

    PubMed Central

    Azimi, Parisa; Shahzadi, Sohrab; Bitaraf, Mohammad Ali; Azar, Maziar; Alikhani, Mazdak; Zali, Alireza; Sadeghi, Sohrab

    2015-01-01

    Background: Treatment of cavernomas remains a challenge in surgically inaccessible regions. The purpose of this study was to evaluate outcomes after gamma-knife surgery (GKS) for these patients. Materials and Methods: A retrospective review of 100 patients treated between 2003 and 2011 was conducted in order to evaluate hemorrhage rates, complications, radiation effects after GKS. Dosage at the tumor margin was stratified into two groups: those that received ≤13 Gy; and those who received >13 Gy. The demographic and clinical characteristics of patients including age, gender, and hemorrhage rates were extracted from care records. Results: The median age was 32.5 years (ranging from 15 to 79). 44% were female. The median follow-up time was 42.2 months (ranging from 24 to 90). The median volume of the lesions was 1050.0 mm3 (ranging from 112.0 to 4100.0) before GKS. A reduction of 27.5% in median size of cavernomas was achieved at the last follow-up. There was 12% treatment-related morbidity after GKS. The hemorrhage rate in the first 2 years after GKS was 4.1% and 1.9% thereafter. There was no mortality due to GKS, and 93 patients were alive at the last follow-up. The radiation-related complication developed with marginal dose 13 Gy. Conclusion: The GKS for cavernomas appears to be a safe and beneficial in carefully selected patients. Low-dose GKS may be effective for the management of cavernous malformations. PMID:25767582

  16. 10 CFR 35.645 - Periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Periodic spot-checks for gamma stereotactic radiosurgery... § 35.645 Periodic spot-checks for gamma stereotactic radiosurgery units. (a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma...

  17. 10 CFR 35.645 - Periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Periodic spot-checks for gamma stereotactic radiosurgery... § 35.645 Periodic spot-checks for gamma stereotactic radiosurgery units. (a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma...

  18. 10 CFR 35.645 - Periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Periodic spot-checks for gamma stereotactic radiosurgery... § 35.645 Periodic spot-checks for gamma stereotactic radiosurgery units. (a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma...

  19. 10 CFR 35.645 - Periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Periodic spot-checks for gamma stereotactic radiosurgery... § 35.645 Periodic spot-checks for gamma stereotactic radiosurgery units. (a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma...

  20. 10 CFR 35.645 - Periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Periodic spot-checks for gamma stereotactic radiosurgery... § 35.645 Periodic spot-checks for gamma stereotactic radiosurgery units. (a) A licensee authorized to use a gamma stereotactic radiosurgery unit for medical use shall perform spot-checks of each gamma...

  1. The Use of Cone Beam Computed Tomography for Image Guided Gamma Knife Stereotactic Radiosurgery: Initial Clinical Evaluation.

    PubMed

    Li, Winnie; Cho, Young-Bin; Ansell, Steve; Laperriere, Normand; Ménard, Cynthia; Millar, Barbara-Ann; Zadeh, Gelareh; Kongkham, Paul; Bernstein, Mark; Jaffray, David A; Chung, Caroline

    2016-09-01

    The present study used cone beam computed tomography (CBCT) to measure the inter- and intrafraction uncertainties for intracranial stereotactic radiosurgery (SRS) using the Leksell Gamma Knife (GK). Using a novel CBCT system adapted to the GK radiosurgery treatment unit, CBCT images were acquired immediately before and after treatment for each treatment session within the context of a research ethics board-approved prospective clinical trial. Patients were immobilized in the Leksell coordinate frame (LCF) for both volumetric CBCT imaging and GK-SRS delivery. The relative displacement of the patient's skull to the stereotactic reference (interfraction motion) was measured for each CBCT scan. Differences between the pre- and post-treatment CBCT scans were used to determine the intrafraction motion. We analyzed 20 pre- and 17 post-treatment CBCT scans in 20 LCF patients treated with SRS. The mean translational pretreatment setup error ± standard deviation in the left-right, anteroposterior, and craniocaudal directions was -0.19 ± 0.32, 0.06 ± 0.27, and -0.23 ± 0.2 mm, with a maximum of -0.74, -0.53, and -0.68 mm, respectively. After an average time between the pre- and post-treatment CBCT scans of 82 minutes (range 27-170), the mean intrafraction error ± standard deviation for the LCF was -0.03 ± 0.05, -0.03 ± 0.18, and -0.03 ± 0.12 mm in the left-right, anteroposterior, and craniocaudual direction, respectively. Using CBCT on a prototype image guided GK Perfexion unit, we were able to measure the inter- and intrafraction positional changes for GK-SRS using the invasive frame. In the era of image guided radiation therapy, the use of CBCT image guidance for both frame- and non-frame-based immobilization systems could serve as a useful quality assurance tool. Our preliminary measurements can guide the application of achievable thresholds for inter- and intrafraction discrepancy when moving to a frameless approach. Copyright © 2016 The Authors

  2. Gamma Knife radiosurgery for glossopharyngeal neuralgia: A study of 21 patients with long-term follow-up.

    PubMed

    Borius, Pierre-Yves; Tuleasca, Constantin; Muraciole, Xavier; Negretti, Laura; Schiappacasse, Luis; Dorenlot, Antoine; Marguet, Maud; Zeverino, Michele; Donnet, Anne; Levivier, Marc; Regis, Jean

    2018-03-01

    Objective Glossopharyngeal neuralgia (GPN) is a very rare condition, affecting the patient's quality of life. We report our experience in drug-resistant, idiopathic GPN, treated with Gamma Knife radiosurgery (GKRS), in terms of safety and efficiency, on a very long-term basis. Methods The study was opened, self-controlled, non-comparative and bicentric (Marseille and Lausanne University Hospitals). Patients treated with GKRS between 2003 and 2015 (models C, 4C and Perfexion) were included. A single 4-mm isocentre was positioned in the cisternal portion of the glossopharyngeal nerve, with a targeting based both on magnetic resonance imaging (MRI) and computed tomography (CT). The mean maximal dose delivered was 81.4 ± 6.7 Gy (median = 85 Gy, range = 60-90 Gy at the 100% isodose line). Results Twenty-one patients (11 women, 10 men) benefited from 25 procedures. The mean follow-up period was 5.2 ± 3 years (range = 0.9-12.1 years). Seventeen (81%) were initially pain-free after GKRS. At three months, six months and one year after radiosurgery, the percentage of patients with good outcome (BNI classes I to IIIA) was 87.6%, 100% and 81.8%, respectively. Ten cases (58.8%) from the initial pain-free ones had a recurrence, after a mean period of 13.6 ± 10.4 months (range = 3.1-36.6 months). Only three patients (14.2%) had recurrences (two for each one of them) requiring further surgeries. Three patients underwent a second GKRS procedure; one case needed a third GKRS. The former procedures were performed at 7, 17, 19 and 30 months after the first one, respectively. Furthermore, two patients needed additional interventions. At last follow-up, 17 cases (80.9%) were still pain-free without medication. The actuarial pain relief without new surgery was 83%. A transient complication (paraesthesia of the edge of the tongue) was seen in one case (4.8%). Conclusion GKRS is a valuable, minimally invasive, surgical alternative for idiopathic GPN

  3. Current gamma knife treatment for ophthalmic branch of primary trigeminal neuralgia

    PubMed Central

    Shan, Guo-Yong; Liang, Hao-Fang; Zhang, Jian-Hua

    2011-01-01

    AIM To probe into problems existing in gamma knife treatment of ophthalmic branch of primary trigeminal neuralgia (TN), and propose a safe and effective solution to the problem. METHODS Through sorting the literature reporting gamma knife treatment of refractory TN in recent years, this article analyzed the advantages and problems of gamma knife treatment of primary TN, and proposed reasonable assessment for existing problems and the possible solution. RESULTS Gamma knife treatment of TN has drawn increasing attention of clinicians due to its unique non-invasion, safety and effectiveness, but there are three related issues to be considered. The first one is the uncertainty of the optimal dose (70-90GY); the second one is the difference in radiotherapy target selection (using a single isocenter or two isocenters); and the third one is the big difference of recurrent pains (specific treatment methods need to be summarized and improved). CONCLUSION For patients with refractory TN, gamma knife treatment can be selected when the medical treatment fails or drug side effects emerge. The analysis of a large number of TN patients receiving gamma knife treatment has shown that this is a safe and effective treatment method. PMID:22553625

  4. Stereotactic radiosurgery for intracranial metastases: linac-based and gamma-dedicated unit approach.

    PubMed

    Alongi, Filippo; Fiorentino, Alba; Mancosu, Pietro; Navarria, Pierina; Giaj Levra, Niccolò; Mazzola, Rosario; Scorsetti, Marta

    2016-07-01

    For intracranial metastases, the role of stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy is well recognized. Historically, the first technology, for stereotactic device able to irradiate a brain tumor volume, was Gamma Knife® (GK). Due to the technological advancement of linear accelerator (Linac), there was a continuous increasing interest in SRS Linac-based applications. In those decades, it was assumed a superiority of GK compared to SRS Linac-based for brain tumor in terms of dose conformity and rapid fall-off dose close to the target. Expert commentary: Recently, due to the Linac technologic advancement, the choice of SRS GK-based is not necessarily so exclusive. The current review discussed in details the technical and clinical aspects comparing the two approaches for brain metastases.

  5. Factors Determining the Clinical Complications of Radiosurgery for AVM.

    PubMed

    Machnowska, Matylda; Taeshineetanakul, Patamintita; Geibprasert, Sasikhan; Menezes, Ravi; Agid, Ronit; Terbrugge, Karel G; Andrade-Souza, Yuri; Schwartz, Michael L; Krings, Timo

    2013-11-01

    To identify the predictors of symptomatic post-radiation T2 signal change in patients with arteriovenous malformations (AVM) treated with radiosurgery. The charts of 211 consecutive patients with arteriovenous malformations treated with either gamma knife radisurgery or linear accelerator radiosurgery between 2000-2009 were retrospectively reviewed. 168 patients had a minimum of 12 months of clinical and radiologic follow-up following the procedure and complete dosage data. Pretreatment characteristics and dosimetric variables were analyzed to identify predictors of adverse radiation effects. 141 patients had no clinical symptomatic complications. 21 patients had global or focal neurological deficits attributed to symptomatic edema. Variables associated with development of symptomatic edema included a non-hemorrhagic symptomatic presentation compared to presentation with hemorrhage, p=0.001; OR (95%CI) = 6.26 (1.99, 19.69); the presence of venous rerouting compared to the lack of venous rerouting, p=0.031; OR (95% CI) = 3.25 (1.20, 8.80); radiosurgery with GKS compared to linear accelerator radiosurgery p = 0.012; OR (95% CI) = 4.58 (1.28, 16.32); and the presence of more than one draining vein compared to a single draining vein p = 0.032; OR (95% CI) = 2.82 (1.06, 7.50). We postulated that the higher maximal doses used with gamma knife radiosurgery may be responsible for the greater number of adverse radiation effects with this modality compared to linear accelerator radiosurgery. We found that AVMs with greater venous complexity and therefore instability resulted in more adverse treatment outcomes, suggesting that AVM angioarchitecture should be considered when making treatment decisions. Facteurs en cause dans les complications cliniques de la radiochirurgie pour une malformation artérioveineuse.

  6. SU-F-SPS-10: The Dosimetric Comparison of GammaKnife and Cyberknife Treatment Plans for Brain SRS Treatment

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sanli, E; Mabhouti, H; Cebe, M

    Purpose: Brain stereotactic radiosurgery (SRS) involves the use of precisely directed, single session radiation to create a desired radiobiologic response within the brain target with acceptable minimal effects on surrounding structures or tissues. In this study, the dosimetric comparison of GammaKnife perfection and Cyberknife M6 treatment plans were made. Methods: Treatment plannings were done for GammaKnife perfection unit using Gammaplan treatment planning system (TPS) on the CT scan of head and neck randophantom simulating the treatment of sterotactic treatments for one brain metastasis. The dose distribution were calculated using TMR 10 algorithm. The treatment planning for the same target weremore » also done for Cyberknife M6 machine using Multiplan (TPS) with Monte Carlo algorithm. Using the same film batch, the net OD to dose calibration curve was obtained using both machine by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. Dose distribution were measured using EBT3 film dosimeter. The measured and calculated doses were compared. Results: The dose distribution in the target and 2 cm beyond the target edge were calculated on TPSs and measured using EBT3 film. For cyberknife treatment plans, the gamma analysis passing rates between measured and calculated dose distributions were 99.2% and 96.7% for target and peripheral region of target respectively. For gammaknife treatment plans, the gamma analysis passing rates were 98.9% and 93.2% for target and peripheral region of target respectively. Conclusion: The study shows that dosimetrically comparable plans are achievable with Cyberknife and GammaKnife. Although TMR 10 algorithm predicts the target dose.« less

  7. Surgery or gamma -knife for the treatment of arteriovenous malformations?

    PubMed

    Shigeno, T; Atsuchi, M; Tanaka, J; Goto, K; Ogata, N

    2000-09-01

    Decision making for either surgery or gamma-knife for the treatment of arteriovenous malformations (AVMs) cannot be uniform. The skill of the neurosurgeon in operating on AVMs is now being compared with that of the gamma-knife. The decision varies from case to case and is to be taken by the neurosurgeon. This report presents three cases in which such decision making was not easy. Case 1 was a non-ruptured cingulate AVM of 2.5 cm diameter in the cingulate cortex. The operative field was anticipated to be very narrow between the parietal bridging veins. Case 2 was a tiny ruptured AVM in the speech-motor area which was buried underneath the cortex. Case 3 was a large ruptured thalamo-stiriate-capsular AVM with feeders from the anterior and posterior choroidal arteries. All cases were operated without serious morbidity. A combination of pre-operative intravascular surgery (cases 1 and 3) or postoperative gamma-knife (case 3) was adopted. In conclusion, there is no unitary rule to decide on surgery or gamma-knife for the treatment of AVMs. It depends on what good or harm the responsible surgeon or the gamma-knife does.

  8. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brainmore » were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.« less

  9. WE-A-304-01: Strategies and Technologies for Cranial Radiosurgery Planning: MLC-Based Linac

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kim, G.

    2015-06-15

    The high fractional doses, stringent requirements for accuracy and precision, and surgical perspective characteristic of intracranial radiosurgery create considerations for treatment planning which are distinct from most other radiotherapy procedures. This session will introduce treatment planning techniques specific to two popular intracranial SRS modalities: Gamma Knife and MLC-based Linac. The basic treatment delivery characteristics of each device will be reviewed with a focus on how those characteristics determine the paradigm used for treatment planning. Basic techniques for treatment planning will be discussed, including considerations such as isodose selection, target and organ-at-risk definition, quality indices, and protection of critical structures. Futuremore » directions for SRS treatment planning will also be discussed. Learning Objectives: Introduce the basic physical principles of intracranial radiosurgery and how they are realized in the treatment planning paradigms for Gamma Knife and Linac radiosurgery. Demonstrate basic treatment planning techniques. Discuss metrics for evaluating SRS treatment plan quality. Discuss recent and future advances in SRS treatment planning. D. Schlesinger receives research support from Elekta, AB.« less

  10. Optimization of the prescription isodose line for Gamma Knife radiosurgery using the shot within shot technique.

    PubMed

    Johnson, Perry B; Monterroso, Maria I; Yang, Fei; Mellon, Eric

    2017-11-25

    This work explores how the choice of prescription isodose line (IDL) affects the dose gradient, target coverage, and treatment time for Gamma Knife radiosurgery when a smaller shot is encompassed within a larger shot at the same stereotactic coordinates (shot within shot technique). Beam profiles for the 4, 8, and 16 mm collimator settings were extracted from the treatment planning system and characterized using Gaussian fits. The characterized data were used to create over 10,000 shot within shot configurations by systematically changing collimator weighting and choice of prescription IDL. Each configuration was quantified in terms of the dose gradient, target coverage, and beam-on time. By analyzing these configurations, it was found that there are regions of overlap in target size where a higher prescription IDL provides equivalent dose fall-off to a plan prescribed at the 50% IDL. Furthermore, the data indicate that treatment times within these regions can be reduced by up to 40%. An optimization strategy was devised to realize these gains. The strategy was tested for seven patients treated for 1-4 brain metastases (20 lesions total). For a single collimator setting, the gradient in the axial plane was steepest when prescribed to the 56-63% (4 mm), 62-70% (8 mm), and 77-84% (16 mm) IDL, respectively. Through utilization of the optimization technique, beam-on time was reduced by more than 15% in 16/20 lesions. The volume of normal brain receiving 12 Gy or above also decreased in many cases, and in only one instance increased by more than 0.5 cm 3 . This work demonstrates that IDL optimization using the shot within shot technique can reduce treatment times without degrading treatment plan quality.

  11. Place of Gamma Knife Stereotactic Radiosurgery in Grade 4 Vestibular Schwannoma Based on Case Series of 86 Patients with Long-Term Follow-Up.

    PubMed

    Lefranc, Michel; Da Roz, Leila Maria; Balossier, Anne; Thomassin, Jean Marc; Roche, Pierre Hugue; Regis, Jean

    2018-06-01

    Grade IV vestibular schwannoma (Koos classification) is generally considered to be an indication for microsurgical resection or combined radiosurgery-microsurgery. However, the place of Gamma Knife stereotactic surgery (GK-SRS), either as first-line treatment or when progression of residual tumor compresses the brainstem, has not been clearly evaluated. This article reports the results of a large case series of patients with grade 4 vestibular schwannoma treated by GK-SRS. All consecutive patients with grade IV vestibular schwannoma treated by GK-SRS in our department between 1996 and 2011 with a minimum follow-up of 3 years were included in this study. 86 patients were treated by GK-SRS with a minimum follow-up of 3 years. Mean follow-up was 6.2 years (3-16 years). The mean age of the patients at the time of GK-SRS was 54.6 years (range: 23-84) and the sex ratio was 0.6. At the time of radiosurgery, no patient presented brainstem dysfunction prior to GK-SRS. 38 patients had functional hearing before treatment. One patient presented mild trigeminal neuralgia before GK-SRS. Tumor control with no clinical deterioration was obtained in 78 patients (90.7%). No radiation-induced brainstem or cranial nerve toxicity was observed in any of these patients. Functional hearing was maintained in 25 patients. 8 (9.3%) patients presented tumor growth and required microsurgical resection in 7 cases and ventricular shunt in 1 case. On the basis of this large series, GK-SRS appears to be a safe and effective treatment option for grade IV vestibular schwannoma for patients with no signs of brainstem dysfunction. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. P13.11USAGE OF CYBER KNIFE HYPOFRACTIONATED RADIOSURGERY IN HIGH GRADE GLIOMAS COMPLEX TREATMENT

    PubMed Central

    Glavatskyi, O.; Buryk, V.M.; Kardash, K.A.; Pylypas, O.P.; Chebotaryova, T.I.

    2014-01-01

    INTRODUCTION: A complex approach to the treatment of malignant brain tumors includes maximum surgical resection, radiotherapy and chemotherapy. The purpose of the current study is to review retrospectively the ability of Cyber Knife (“Accuray Incorporated”, Sunnyvale, CA, USA) radiosurgery to provide local tumor control of newly diagnosed or recurrent malignant brain tumors. MATERIAL AND METHOD: 26 patients with malignant brain tumors (glioblastoma multiform (GBM) - 14 patients, anaplastic astrocytoma (AA) - 12 patients) were treated in 2012-2013 with Cyber Knife stereotactic radiosurgery. Before radiosurgery 8 patients had complete removal of the tumor, 9 patients had subtotal resection and 9 patients had biopsy. 17 patients received adjuvant chemotherapy with temozolomide according to the different treatment protocols. 9 patients who were previously irradiated received re-irradiation. In all patients CT, MRI, PET (native, enhanced, CT-perfusion, MRI-diffusion (DWI) studies) before and after treatment were performed with (3, 6, 12, 18 month follow up). The volume of tumors ranged from 10-12 cm3 to 101,1 cm3. The maximum mean dose of irradiation applied was 36.99 Gy (ranged from 21,3 Gy to 48,8 Gy). 3-6 fractions of hypofractionated treatment were used. RESULTS: At this stage of the study, we assessed the absence of complications after stereotactic hypofractionated radiosurgery. Objective survival evaluation has being performed in 12-24 months after radiosurgical treatment. A significant decrease in the number and severity of seizures was seen in 7 patients out of 21 (33 %). 18 patients (64%) had regression of limb weakness. In case of biopsy 7 of 9 tumors (78 %) showed a decrease in volume. In patients with clinical deterioration (3 patients) repeated surgical treatment was performed. All of them had signs of post-irradiation necrosis and pathomorphosis in tumor tissue. Median overall survival and progression free survival were 17 months and 11 months

  13. Comparison of full width at half maximum and penumbra of different Gamma Knife models.

    PubMed

    Asgari, Sepideh; Banaee, Nooshin; Nedaie, Hassan Ali

    2018-01-01

    As a radiosurgical tool, Gamma Knife has the best and widespread name recognition. Gamma Knife is a noninvasive intracranial technique invented and developed by Swedish neurosurgeon Lars Leksell. The first commercial Leksell Gamma Knife entered the therapeutic armamentarium at the University of Pittsburgh in the United States on August 1987. Since that time, different generation of Gamma Knife developed. In this study, the technical points and dosimetric parameters including full width at half maximum and penumbra on different generation of Gamma Knife will be reviewed and compared. The results of this review study show that the rotating gamma system provides a better dose conformity.

  14. Development of stereotactic radiosurgery using carbon beams (carbon-knife)

    NASA Astrophysics Data System (ADS)

    Keawsamur, Mintra; Matsumura, Akihiko; Souda, Hikaru; Kano, Yosuke; Torikoshi, Masami; Nakano, Takashi; Kanai, Tatsuaki

    2018-02-01

    The aim of this research is to develop a stereotactic-radiosurgery (SRS) technique using carbon beams to treat small intracranial lesions; we call this device the carbon knife. A 2D-scanning method is adapted to broaden a pencil beam to an appropriate size for an irradiation field. A Mitsubishi slow extraction using third order resonance through a rf acceleration system stabilized by a feed-forward scanning beam using steering magnets with a 290 MeV/u initial beam energy was used for this purpose. Ridge filters for spread-out Bragg peaks (SOBPs) with widths of 5 mm, 7.5 mm, and 10 mm were designed to include fluence-attenuation effects. The collimator, which defines field shape, was used to reduce the lateral penumbra. The lateral-penumbra width at the SOBP region was less than 2 mm for the carbon knife. The penumbras behaved almost the same when changing the air gap, but on the other hand, increasing the range-shifter thickness mostly broadened the lateral penumbra. The physical-dose rates were approximate 6 Gy s-1 and 4.5 Gy s-1 for the 10  ×  10 mm2 and 5  ×  5 mm2 collimators, respectively.

  15. Characterization of system-related geometric distortions in MR images employed in Gamma Knife radiosurgery applications.

    PubMed

    Pappas, E P; Seimenis, I; Moutsatsos, A; Georgiou, E; Nomikos, P; Karaiskos, P

    2016-10-07

    This work provides characterization of system-related geometric distortions present in MRIs used in Gamma Knife (GK) stereotactic radiosurgery (SRS) treatment planning. A custom-made phantom, compatible with the Leksell stereotactic frame model G and encompassing 947 control points (CPs), was utilized. MR images were obtained with and without the frame, thus allowing discrimination of frame-induced distortions. In the absence of the frame and following compensation for field inhomogeneities, measured average CP disposition owing to gradient nonlinearities was 0.53 mm. In presence of the frame, contrarily, detected distortion was greatly increased (up to about 5 mm) in the vicinity of the frame base due to eddy currents induced in the closed loop of its aluminum material. Frame-related distortion was obliterated at approximately 90 mm from the frame base. Although the region with the maximum observed distortion may not lie within the GK treatable volume, the presence of the frame results in distortion of the order of 1.5 mm at a 7 cm distance from the center of the Leksell space. Additionally, severe distortions observed outside the treatable volume could possibly impinge on the delivery accuracy mainly by adversely affecting the registration process (e.g. the position of the lower part of the N-shaped fiducials used to define the stereotactic space may be miss-registered). Images acquired with a modified version of the frame developed by replacing its front side with an acrylic bar, thus interrupting the closed aluminum loop and reducing the induced eddy currents, were shown to benefit from relatively reduced distortion. System-related distortion was also identified in patient MR images. Using corresponding CT angiography images as a reference, an offset of 1.1 mm was detected for two vessels lying in close proximity to the frame base, while excellent spatial agreement was observed for a vessel far apart from the frame base.

  16. Characterization of system-related geometric distortions in MR images employed in Gamma Knife radiosurgery applications

    NASA Astrophysics Data System (ADS)

    Pappas, E. P.; Seimenis, I.; Moutsatsos, A.; Georgiou, E.; Nomikos, P.; Karaiskos, P.

    2016-10-01

    This work provides characterization of system-related geometric distortions present in MRIs used in Gamma Knife (GK) stereotactic radiosurgery (SRS) treatment planning. A custom-made phantom, compatible with the Leksell stereotactic frame model G and encompassing 947 control points (CPs), was utilized. MR images were obtained with and without the frame, thus allowing discrimination of frame-induced distortions. In the absence of the frame and following compensation for field inhomogeneities, measured average CP disposition owing to gradient nonlinearities was 0.53 mm. In presence of the frame, contrarily, detected distortion was greatly increased (up to about 5 mm) in the vicinity of the frame base due to eddy currents induced in the closed loop of its aluminum material. Frame-related distortion was obliterated at approximately 90 mm from the frame base. Although the region with the maximum observed distortion may not lie within the GK treatable volume, the presence of the frame results in distortion of the order of 1.5 mm at a 7 cm distance from the center of the Leksell space. Additionally, severe distortions observed outside the treatable volume could possibly impinge on the delivery accuracy mainly by adversely affecting the registration process (e.g. the position of the lower part of the N-shaped fiducials used to define the stereotactic space may be miss-registered). Images acquired with a modified version of the frame developed by replacing its front side with an acrylic bar, thus interrupting the closed aluminum loop and reducing the induced eddy currents, were shown to benefit from relatively reduced distortion. System-related distortion was also identified in patient MR images. Using corresponding CT angiography images as a reference, an offset of 1.1 mm was detected for two vessels lying in close proximity to the frame base, while excellent spatial agreement was observed for a vessel far apart from the frame base.

  17. Recurrent Juvenile Nasopharyngeal Angiofibroma Treated with Gamma Knife Surgery

    PubMed Central

    Park, Chul-Kee; Paek, Sun Ha; Chung, Hyun-Tai; Jung, Hee-Won

    2006-01-01

    Radiosurgery has been rarely applied for juvenile nasopharyngeal angiofibroma (JNA) and cumulative reports are lacking. The authors report a case of successful treatment of recurred JNA with gamma knife surgery (GKS). A 48-yr-old man was presented with right visual acuity deterioration and brain magnetic resonance images (MRI) disclosed a 3 cm-sized intraorbital mass in the right orbit. He underwent a right fronto-temporal craniotomy and the mass was subtotally removed to preserve visual function. Histological diagnosis confirmed JNA in typical nature. However, the vision gradually worsened to fail four years after operation. MRI then showed regrowth of the tumor occupying most of the right orbit. GKS was done for the recurred lesion. A dose of 17 Gy was delivered to the 50% isodose line of tumor margin. During the following four-year follow-up period, the mass disappeared almost completely without any complications. Usually JNA can be exclusively diagnosed by radiological study alone. So this report of successful treatment of JNA with GKS may provide an important clue for the novel indication of GKS. PMID:16891831

  18. Stereotactic radiosurgery in hemangioblastoma: Experience over 14 years

    PubMed Central

    Goyal, Nishant; Agrawal, Deepak; Singla, Raghav; Kale, Shashank Sharad; Singh, Manmohan; Sharma, Bhawani Shankar

    2016-01-01

    Background: Although gamma knife has been advocated for hemangioblastomas, it is not used widely by neurosurgeons. Objective: We review our experience over 14 years in an attempt to define the role of stereotactic radiosurgery (SRS) in the management of hemangioblastomas. Patients and Methods: A retrospective study was conducted on all patients of hemangioblastoma who underwent SRS at our institute over a period of 14 years (1998–2011). Gamma knife plans, clinical history, and radiology were reviewed for all patients. Results: A total of 2767 patients underwent gamma knife during the study period. Of these, 10 (0.36%) patients were treated for 24 hemangioblastomas. Eight patients (80%) had von Hippel-Lindau disease while two had sporadic hemangioblastomas. The median peripheral dose (50% isodose) delivered to the tumors was 29.9 Gy. Clinical and radiological follow-up data were available for eight patients. Of these, two were re-operated for persisting cerebellar symptoms. The remaining six patients were recurrence-free at a mean follow-up of 48 months (range 19–108 months). One patient had an increase in cyst volume along with a decrease in the size of the mural nodule. Conclusions: SRS should be the first option for asymptomatic hemangioblastomas. Despite the obvious advantages, gamma knife is not widely used as an option for hemangioblastomas. PMID:26933339

  19. Relapsed or refractory primary central nervous system lymphoma radiosurgery: Report of the International Gamma Knife Research Foundation.

    PubMed

    Shin, Samuel M; Silverman, Joshua S; Bowden, Greg; Mathieu, David; Yang, Huai-Che; Lee, Cheng-Chia; Tam, Moses; Szelemej, Paul; Kaufmann, Anthony M; Cohen-Inbar, Or; Sheehan, Jason; Niranjan, Ajay; Lunsford, L Dade; Kondziolka, Douglas

    2017-01-01

    Stereotactic radiosurgery (SRS) can be used as part of multimodality management for patients with primary central nervous system lymphoma (PCNSL). The objective of this study is to evaluate outcomes of SRS for this disease. The International Gamma Knife Research Foundation identified 23 PCNSL patients who underwent SRS for either relapsed (intracerebral in-field or out-of-field tumor recurrences) or refractory disease from 1995-2014. All 23 patients presented with RPA Class I or II PCNSL, and were initially treated with a median of 7 cycles of methotrexate-based chemotherapy regimens (range, 3-26 cycles). Ten received prior whole brain radiation (WBRT) to a median dose of 43 Gy (range, 24-55 Gy). Sixteen presented with relapsed PCNSL, and seven presented with refractory disease. Twenty-three received 26 procedures of SRS. The median tumor volume was 4 cm 3 (range, 0.1-26 cm 3 ), and the median margin dose was 15 Gy (range, 8-20 Gy). Median follow-up from SRS was 11 months (interquartile range, 5.7-33.2 months). Twenty presented with treatment response to twenty-three tumors (12 complete, 11 partial). Fourteen patients relapsed or were refractory to salvage SRS, and local control was 95%, 91%, and 75% at 3, 6, and 12 months post SRS. Intracranial (in-field and out-of-field) and distant (systemic) PFS was 86%, 81%, and 55% at 3, 6, and 12 months post SRS. Toxicity of SRS was low, with one developing an adverse radiation effect requiring no additional intervention. Although methotrexate-based chemotherapy regimens with or without WBRT is the first-line management option for PCNSL, SRS may be used as an alternative option in properly selected patients with smaller relapsed or refractory PCNSL tumors.

  20. Efficacy and Quality of Life Outcomes in Patients With Atypical Trigeminal Neuralgia Treated With Gamma-Knife Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dhople, Anil; Kwok, Young; Chin, Lawrence

    2007-10-01

    Purpose: To assess efficacy and quality of life (QOL) outcomes associated with gamma-knife radiosurgery (GK-RS) in treating atypical trigeminal neuralgia (ATN) compared with classic trigeminal neuralgia (CTN). Methods and Materials: Between September 1996 and September 2004, 35 cases of ATN were treated with GK-RS. Patients were categorized into two groups: Group I comprised patients presenting with ATN (57%); Group II consisted of patients presenting with CTN then progressing to ATN (43%). Median prescription dose 75 Gy (range, 70-80 Gy) was delivered to trigeminal nerve root entry zone. Treatment efficacy and QOL improvements were assessed with a standardized questionnaire. Results: Withmore » median follow-up of 29 months (range, 3-74 months), 72% reported excellent/good outcomes, with mean time to relief of 5.8 weeks (range, 0-24 weeks) and mean duration of relief of 62 weeks (range, 1-163 weeks). This rate of pain relief is similar to rate achieved in our previously reported experience treating CTN with GK-RS (p = 0.36). There was a trend toward longer time to relief (p = 0.059), and shorter duration of relief (p = 0.067) in patients with ATN. There was no difference in rate of, time to, or duration of pain relief between Groups I and II. Of the patients with ATN, 88% discontinued or decreased the use of pain medications. Among the patients with sustained pain relief, QOL improved an average of 85%. Conclusion: This is the largest reported GK-RS experience for the treatment of ATN. Patients with ATN can achieve rates of pain relief similar to those in patients with CTN. Further follow-up is necessary to assess adequately the durability of response.« less

  1. Gamma knife radiosurgery for Cushing's disease and Nelson's syndrome.

    PubMed

    Marek, Josef; Ježková, Jana; Hána, Václav; Kršek, Michal; Liščák, Roman; Vladyka, Vilibald; Pecen, Ladislav

    2015-06-01

    This paper presents our 18 years of experience in treating ACTH secreting adenomas (Cushing's disease and Nelson's syndrome) using the Leksell gamma knife (LGK) irradiation. Twenty-six patients with Cushing's disease were followed-up after LGK irradiation for 48-216 months (median 78 months). Seventeen patients had undergone previous surgery, in nine patients LGK irradiation was the primary therapy. Furthermore, 14 patients with Nelson's syndrome were followed-up for 30-204 months (median 144 months). LGK treatment resulted in hormonal normalization in 80.7 % of patients with Cushing's disease. Time to normalization was 6-54 months (median 30 months). The volume of the adenoma decreased in 92.3% (in 30.7% disappeared completely). There was no recurrence of the disease. In all 14 patients with Nelson's syndrome ACTH levels decreased (in two patients fully normalized) their ACTH levels. When checked up 5-10 years after irradiation regrowth of the adenoma was only detected in one patient (9.1%), in 27.3% adenoma volume remained unchanged, in 45.4% adenoma volume decreased and in 18.2% adenoma completely disappeared. Hypopituitarism did not develop in any patient where the critical dose to the pituitary and distal infundibulum was respected. LGK radiation represents an effective and well-tolerated option for the treatment of patients with Cushing's disease after unsuccessful surgery and may be valuable even as a primary treatment in patients who are not suitable for, or refuse, surgery. In the case of Nelson's syndrome it is possible to impede tumorous growth and control the size of the adenoma in almost all patients.

  2. Iridium-Knife: Another knife in radiation oncology.

    PubMed

    Milickovic, Natasa; Tselis, Nikolaos; Karagiannis, Efstratios; Ferentinos, Konstantinos; Zamboglou, Nikolaos

    Intratarget dose escalation with superior conformity is a defining feature of three-dimensional (3D) iridium-192 ( 192 Ir) high-dose-rate (HDR) brachytherapy (BRT). In this study, we analyzed the dosimetric characteristics of interstitial 192 Ir HDR BRT for intrathoracic and cerebral malignancies. We examined the dose gradient sharpness of HDR BRT compared with that of linear accelerator-based stereotactic radiosurgery and stereotactic body radiation therapy, usually called X-Knife, to demonstrate that it may as well be called a Knife. Treatment plans for 10 patients with recurrent glioblastoma multiforme or intrathoracic malignancies, five of each entity, treated with X-Knife (stereotactic radiosurgery for glioblastoma multiforme and stereotactic body radiation therapy for intrathoracic malignancies) were replanned for simulated HDR BRT. For 3D BRT planning, we used identical structure sets and dose prescription as for the X-Knife planning. The indices for qualitative treatment plan analysis encompassed planning target volume coverage, conformity, dose falloff gradient, and the maximum dose-volume limits to different organs at risk. Volume coverage in HDR plans was comparable to that calculated for X-Knife plans with no statistically significant difference in terms of conformity. The dose falloff gradient-sharpness-of the HDR plans was considerably steeper compared with the X-Knife plans. Both 3D 192 Ir HDR BRT and X-Knife are effective means for intratarget dose escalation with HDR BRT achieving at least equal conformity and a steeper dose falloff at the target volume margin. In this sense, it can reasonably be argued that 3D 192 Ir HDR BRT deserves also to be called a Knife, namely Iridium-Knife. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  3. γTools: A modular multifunction phantom for quality assurance in GammaKnife treatments.

    PubMed

    Calusi, Silvia; Noferini, Linhsia; Marrazzo, Livia; Casati, Marta; Arilli, Chiara; Compagnucci, Antonella; Talamonti, Cinzia; Scoccianti, Silvia; Greto, Daniela; Bordi, Lorenzo; Livi, Lorenzo; Pallotta, Stefania

    2017-11-01

    We present the γTools, a new phantom designed to assess geometric and dosimetric accuracy in Gamma Knife treatments, together with first tests and results of applications. The phantom is composed of two modules: the imaging module, a regular grid of 1660 control points to evaluate image distortions and image registration result and the dosimetry module for delivered dose distribution measurements. The phantom is accompanied by a MatLab routine for image distortions quantification. Dose measurement are performed with Gafchromic films fixed between two inserts and placed in various positions and orientations inside the dosimetry module thus covering a volume comparable to the full volume of a head. Tests performed to assess the accuracy and precision of the imaging module demonstrated sub-millimetric values. As an example of possible applications, the phantom was employed to measure image distortions of two MRI scanners and to perform dosimetric studies of single shots delivered to homogeneous and heterogeneous materials. Due to the phantom material, the measured absolute dose do not correspond to the planned dose; doses comparisons are thus carried out between normalized dose distributions. Finally, an end-to-end test was carried out in the treatment of a neuroma-like target which resulted in a 100% gamma passing rate (2% local, 2 mm) and a distance between the real target perimeter and the prescription isodose centroids of about 1 mm. The tests demonstrate that the proposed phantom is suitable to assess both the geometrical and relative dosimetric accuracy of Gamma Knife radiosurgery treatments. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  4. Radiation shielding for gamma stereotactic radiosurgery units

    PubMed Central

    2007-01-01

    Shielding calculations for gamma stereotactic radiosurgery units are complicated by the fact that the radiation is highly anisotropic. Shielding design for these devices is unique. Although manufacturers will answer questions about the data that they provide for shielding evaluation, they will not perform calculations for customers. More than 237 such units are now installed in centers worldwide. Centers installing a gamma radiosurgery unit find themselves in the position of having to either invent or reinvent a method for performing shielding design. This paper introduces a rigorous and conservative method for barrier design for gamma stereotactic radiosurgery treatment rooms. This method should be useful to centers planning either to install a new unit or to replace an existing unit. The method described here is consistent with the principles outlined in Report No. 151 from the U.S. National Council on Radiation Protection and Measurements. In as little as 1 hour, a simple electronic spreadsheet can be set up, which will provide radiation levels on planes parallel to the barriers and 0.3 m outside the barriers. PACS numbers: 87.53.Ly, 87.56By, 87.52Tr

  5. Real-time inverse planning for Gamma Knife radiosurgery.

    PubMed

    Wu, Q Jackie; Chankong, Vira; Jitprapaikulsarn, Suradet; Wessels, Barry W; Einstein, Douglas B; Mathayomchan, Boonyanit; Kinsella, Timothy J

    2003-11-01

    The challenges of real-time Gamma Knife inverse planning are the large number of variables involved and the unknown search space a priori. With limited collimator sizes, shots have to be heavily overlapped to form a smooth prescription isodose line that conforms to the irregular target shape. Such overlaps greatly influence the total number of shots per plan, making pre-determination of the total number of shots impractical. However, this total number of shots usually defines the search space, a pre-requisite for most of the optimization methods. Since each shot only covers part of the target, a collection of shots in different locations and various collimator sizes selected makes up the global dose distribution that conforms to the target. Hence, planning or placing these shots is a combinatorial optimization process that is computationally expensive by nature. We have previously developed a theory of shot placement and optimization based on skeletonization. The real-time inverse planning process, reported in this paper, is an expansion and the clinical implementation of this theory. The complete planning process consists of two steps. The first step is to determine an optimal number of shots including locations and sizes and to assign initial collimator size to each of the shots. The second step is to fine-tune the weights using a linear-programming technique. The objective function is to minimize the total dose to the target boundary (i.e., maximize the dose conformity). Results of an ellipsoid test target and ten clinical cases are presented. The clinical cases are also compared with physician's manual plans. The target coverage is more than 99% for manual plans and 97% for all the inverse plans. The RTOG PITV conformity indices for the manual plans are between 1.16 and 3.46, compared to 1.36 to 2.4 for the inverse plans. All the inverse plans are generated in less than 2 min, making real-time inverse planning a reality.

  6. On the development of a comprehensive MC simulation model for the Gamma Knife Perfexion radiosurgery unit

    NASA Astrophysics Data System (ADS)

    Pappas, E. P.; Moutsatsos, A.; Pantelis, E.; Zoros, E.; Georgiou, E.; Torrens, M.; Karaiskos, P.

    2016-02-01

    This work presents a comprehensive Monte Carlo (MC) simulation model for the Gamma Knife Perfexion (PFX) radiosurgery unit. Model-based dosimetry calculations were benchmarked in terms of relative dose profiles (RDPs) and output factors (OFs), against corresponding EBT2 measurements. To reduce the rather prolonged computational time associated with the comprehensive PFX model MC simulations, two approximations were explored and evaluated on the grounds of dosimetric accuracy. The first consists in directional biasing of the 60Co photon emission while the second refers to the implementation of simplified source geometric models. The effect of the dose scoring volume dimensions in OF calculations accuracy was also explored. RDP calculations for the comprehensive PFX model were found to be in agreement with corresponding EBT2 measurements. Output factors of 0.819  ±  0.004 and 0.8941  ±  0.0013 were calculated for the 4 mm and 8 mm collimator, respectively, which agree, within uncertainties, with corresponding EBT2 measurements and published experimental data. Volume averaging was found to affect OF results by more than 0.3% for scoring volume radii greater than 0.5 mm and 1.4 mm for the 4 mm and 8 mm collimators, respectively. Directional biasing of photon emission resulted in a time efficiency gain factor of up to 210 with respect to the isotropic photon emission. Although no considerable effect on relative dose profiles was detected, directional biasing led to OF overestimations which were more pronounced for the 4 mm collimator and increased with decreasing emission cone half-angle, reaching up to 6% for a 5° angle. Implementation of simplified source models revealed that omitting the sources’ stainless steel capsule significantly affects both OF results and relative dose profiles, while the aluminum-based bushing did not exhibit considerable dosimetric effect. In conclusion, the results of this work suggest that any PFX

  7. Dosimetric effects of Onyx embolization on Gamma Knife arteriovenous malformation dose distributions.

    PubMed

    Schlesinger, David J; Nordström, Håkan; Lundin, Anders; Xu, Zhiyuan; Sheehan, Jason P

    2016-12-01

    OBJECTIVE Patients with arteriovenous malformations (AVMs) treated with Gamma Knife radiosurgery (GKRS) subsequent to embolization suffer from elevated local failure rates and differences in adverse radiation effects. Onyx is a common embolic material for AVMs. Onyx is formulated with tantalum, a high atomic number (Z = 73) element that has been investigated as a source of dosimetric uncertainty contributing to the less favorable clinical results. However, prior studies have not modeled the complicated anatomical and beam geometries characteristic of GKRS. This study investigated the magnitude of dose perturbation that can occur due to Onyx embolization using clinically realistic anatomical and Gamma Knife beam models. METHODS Leksell GammaPlan (LGP) was used to segment the AVM nidus and areas of Onyx from postcontrast stereotactic MRI for 7 patients treated with GKRS postembolization. The resulting contours, skull surface, and clinically selected dose distributions were exported from LGP in DICOM-RT (Digital Imaging and Communications in Medicine-radiotherapy) format. Isocenter locations and dwell times were recorded from the LGP database. Contours were converted into 3D mesh representations using commercial and in-house mesh-editing software. The resulting data were imported into a Monte Carlo (MC) dose calculation engine (Pegasos, Elekta Instruments AB) with a beam geometry for the Gamma Knife Perfexion. The MC-predicted dose distributions were calculated with Onyx assigned manufacturer-reported physical constants (MC-Onyx), and then compared with corresponding distributions in which Onyx was reassigned constants for water (MC-water). Differences in dose metrics were determined, including minimum, maximum, and mean dose to the AVM nidus; selectivity index; and target coverage. Combined differences in dose magnitude and distance to agreement were calculated as 3D Gamma analysis passing rates using tolerance criteria of 0.5%/0.5 mm, 1.0%/1.0 mm, and 3.0%/3.0 mm

  8. Postcontrast T1 Mapping for Differential Diagnosis of Recurrence and Radionecrosis after Gamma Knife Radiosurgery for Brain Metastasis.

    PubMed

    Wang, B; Zhang, Y; Zhao, B; Zhao, P; Ge, M; Gao, M; Ding, F; Xu, S; Liu, Y

    2018-06-01

    The differential diagnosis of radionecrosis and tumor recurrence in brain metastases is challenging. We investigated the diagnostic efficiency of postcontrast T1 mapping in solving this problem. Between March 2016 and June 2017, fifty-six patients with brain metastases who underwent contrast-enhanced cerebral T1 mapping were recruited for this prospective study. The findings revealed new enhancement after gamma knife radiosurgery. The subjects were assigned to radionecrosis and recurrence groups based on follow-up (median, 11.5 months) and histopathologic results. T1 values of lesions 5 (T1 5min ) and 60 (T1 60min ) minutes after administration of contrast agent and their difference (T1 differ ) were compared between the 2 groups with the 2-tailed Mann-Whitney U test. Receiver operating characteristic curves were used to determine the optimum cutoff values for differential diagnosis. There were significant differences between the 2 groups in T1 5min , T1 60min , and T1 differ values ( P = .012, P = .004, and P < .001, respectively). Relative to T1 5min and T1 60min , T1 differ exhibited greater sensitivity and specificity ( P < .001, respectively) in identifying radionecrosis. The optimum T1 differ value for differential diagnosis was 71.1 ms (area under the curve = 0.97; 95% CI, 0.93-1.00), with sensitivity and specificity of 81.5% and 96.5%, respectively. Postcontrast T1 mapping is optimal for the differential diagnosis of radionecrosis and tumor recurrence. Among T1 parameters, T1 differ is the most powerful parameter for differential diagnosis. Advantages in terms of quantitative analysis and high resolution portend the wide use of postcontrast T1 mapping in the future. © 2018 by American Journal of Neuroradiology.

  9. TH-A-BRC-01: AAPM TG-135U1 QA for Robotic Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dieterich, S.

    AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance -more » Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and

  10. Analysis of 2000 cases treated with gamma knife surgery: validating eligibility criteria for a prospective multi-institutional study of stereotactic radiosurgery alone for treatment of patients with 1-10 brain metastases (JLGK0901) in Japan

    PubMed Central

    Higuchi, Yoshinori; Nagano, Osamu; Sato, Yasunori; Yamamoto, Masaaki; Ono, Junichi; Saeki, Naokatsu; Miyakawa, Akifumi; Hirai, Tatsuo

    2012-01-01

    Objective The Japan Leksell Gamma Knife (JLGK) Society has conducted a prospective multi-institute study (JLGK0901, UNIN000001812) for selected patients in order to prove the effectiveness of stereotactic radiosurgery (SRS) alone using the gamma knife (GK) for 1-10 brain lesions. Herein, we verify the validity of 5 major patient selection criteria for the JLGK0901 trial. Materials and Methods Between 1998 and 2010, 2246 consecutive cases with 10352 brain metastases treated with GK were analyzed to determine the validity of the following 5 major JLGK0901 criteria; 1) 1-10 brain lesions, 2) less than 10 cm3 volume of the largest tumor, 3) no more than 15 cm3 total tumor volume, 4) no cerebrospinal fluid (CSF) dissemination, 5) Karnofsky performance status (KPS) score ≥70. Results For cases with >10 brain metastases, salvage treatments for new lesions were needed more frequently. The tumor control rate for lesions larger than 10 cm3 was significantly lower than that of tumors <10 cm3. Overall, neurological and qualitative survivals (OS, NS, QS) of cases with >15 cm3 total tumor volume or positive magnetic resonance imaging findings of CSF were significantly poorer. Outcomes in cases with KPS <70 were significantly poorer in terms of OS. Conclusion Our retrospective results of 2246 GK-treated cases verified the validity of the 5 major JLGK0901 criteria. The inclusion criteria for the JLGK0901 study are appearently good indications for SRS. PMID:29296339

  11. Evaluation of the stability of the stereotactic Leksell Frame G in Gamma Knife radiosurgery.

    PubMed

    Rojas-Villabona, Alvaro; Miszkiel, Katherine; Kitchen, Neil; Jäger, Rolf; Paddick, Ian

    2016-05-08

    The purpose of this study was to evaluate the stability of the Leksell Frame G in Gamma Knife radiosurgery (GKR). Forty patients undergoing GKR underwent pretreatment stereotactic MRI for GKR planning and stereotactic CT immediately after GKR. The stereotactic coordinates of four anatomical landmarks (cochlear apertures and the summits of the anterior post of the superior semicircular canals, bilaterally) were measured by two evaluators on two separate occasions in the pre-treatment MRI and post-treatment CT scans and the absolute distance between the observations is reported. The measurement method was validated with an indepen-dent group of patients who underwent both stereotactic MRI and CT imaging before treatment (negative controls; n: 5). Patients undergoing GKR for arteriovenous malformations (AVM) also underwent digital subtraction angiography (DSA), which could result in extra stresses on the frame. The distance between landmark local-ization in the scans for the negative control group (0.63 mm; 95% CI: 0.57-0.70; SD: 0.29) represents the overall consistency of the evaluation method and provides an estimate of the minimum displacement that could be detected by the study. Two patients in the study group had the fiducial indicator box accidentally misplaced at post-treatment CT scanning. This simulated the scenario of a frame displacement, and these cases were used as positive controls to demonstrate that the evaluation method is capable of detecting a discrepancy between the MRI and CT scans, if there was one. The mean distance between the location of the landmarks in the pretreatment MRI and post-treatment CT scans for the study group was 0.71 mm (95% CI: 0.68-0.74; SD:0.32), which was not statistically different from the over-all uncertainty of the evaluation method observed in the negative control group (p = 0.06). The subgroup of patients with AVM (n: 9), who also underwent DSA, showed a statistically significant difference between the location of the

  12. A new Gamma Knife registered radiosurgery paradigm: Tomosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, X.; Maciunas, R. J.; Dean, D.

    This study proposes and simulates an inverse treatment planning and a continuous dose delivery approach for the Leksell Gamma Knife registered (LGK, Elekta, Stockholm, Sweden) which we refer to as 'Tomosurgery'. Tomosurgery uses an isocenter that moves within the irradiation field to continuously deliver the prescribed radiation dose in a raster-scanning format, slice by slice, within an intracranial lesion. Our Tomosurgery automated (inverse) treatment planning algorithm utilizes a two-stage optimization strategy. The first stage reduces the current three-dimensional (3D) treatment planning problem to a series of more easily solved 2D treatment planning subproblems. In the second stage, those 2D treatmentmore » plans are assembled to obtain a final 3D treatment plan for the entire lesion. We created Tomosurgery treatment plans for 11 patients who had already received manually-generated LGK treatment plans to treat brain tumors. For the seven cases without critical structures (CS), the Tomosurgery treatment plans showed borderline to significant improvement in within-tumor dose standard deviation (STD) (p<0.058, or p<0.011 excluding case 2) and conformality (p<0.042), respectively. In three of the four cases that presented CS, the Tomosurgery treatment plans showed no statistically significant improvements in dose conformality (p<0.184), and borderline significance in improving within-tumor dose homogeneity (p<0.054); CS damage measured by V{sub 20} or V{sub 30} (i.e., irradiated CS volume that receives {>=}20% or {>=}30% of the maximum dose) showed no significant improvement in the Tomosurgery treatment plans (p<0.345 and p<0.423, respectively). However, the overall CS dose volume histograms were improved in the Tomosurgery treatment plans. In addition, the LGK Tomosurgery inverse treatment planning required less time than standard of care, forward (manual) LGK treatment planning (i.e., 5-35 min vs 1-3 h) for all 11 cases. We expect that LGK Tomosurgery will

  13. Determination of small field synthetic single-crystal diamond detector correction factors for CyberKnife, Leksell Gamma Knife Perfexion and linear accelerator.

    PubMed

    Veselsky, T; Novotny, J; Pastykova, V; Koniarova, I

    2017-12-01

    The aim of this study was to determine small field correction factors for a synthetic single-crystal diamond detector (PTW microDiamond) for routine use in clinical dosimetric measurements. Correction factors following small field Alfonso formalism were calculated by comparison of PTW microDiamond measured ratio M Qclin fclin /M Qmsr fmsr with Monte Carlo (MC) based field output factors Ω Qclin,Qmsr fclin,fmsr determined using Dosimetry Diode E or with MC simulation itself. Diode measurements were used for the CyberKnife and Varian Clinac 2100C/D linear accelerator. PTW microDiamond correction factors for Leksell Gamma Knife (LGK) were derived using MC simulated reference values from the manufacturer. PTW microDiamond correction factors for CyberKnife field sizes 25-5 mm were mostly smaller than 1% (except for 2.9% for 5 mm Iris field and 1.4% for 7.5 mm fixed cone field). The correction of 0.1% and 2.0% for 8 mm and 4 mm collimators, respectively, needed to be applied to PTW microDiamond measurements for LGK Perfexion. Finally, PTW microDiamond M Qclin fclin /M Qmsr fmsr for the linear accelerator varied from MC corrected Dosimetry Diode data by less than 0.5% (except for 1 × 1 cm 2 field size with 1.3% deviation). Regarding low resulting correction factor values, the PTW microDiamond detector may be considered an almost ideal tool for relative small field dosimetry in a large variety of stereotactic and radiosurgery treatment devices. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  14. Neuropsychological results after gamma knife radiosurgery for mesial temporal lobe epilepsy.

    PubMed

    Vojtěch, Zdeněk; Krámská, Lenka; Malíková, Hana; Stará, Michaela; Liščák, Roman

    2015-01-01

    The aim of this study is to summarize our experience with neuropsychological changes after radiosurgical treatment for mesial temporal lobe epilepsy and subsequent surgery due to insufficient seizure control. Between November 1995 and May 1999, 14 patients underwent radiosurgical entorhinoamygdalohippocampectomy with a marginal dose of 18, 20 or 25 Gy to the 50% isodose. 9 of these patients subsequently underwent surgery. We compared Memory Quotients and Intelligence Quotients before and after the interventions. We found a slight, but nonsignificant decline in intelligence and memory quotients one year after GKRS. Two years after radiosurgery there were no significant changes in any of the quotients. After surgery, we found significant increase in Global and Visual MQ, (p<0.05). There were no statistically significant changes in verbal memory and intelligence performance after surgery. Epilepsy surgery after unsuccessful radiosurgery could lead to improvements in cognitive functions in patients with mesial temporal lobe epilepsy.

  15. A new strategy of CyberKnife treatment system based radiosurgery followed by early use of adjuvant bevacizumab treatment for brain metastasis with extensive cerebral edema.

    PubMed

    Wang, Yang; Wang, Enmin; Pan, Li; Dai, Jiazhong; Zhang, Nan; Wang, Xin; Liu, Xiaoxia; Mei, Guanghai; Sheng, Xiaofang

    2014-09-01

    Bevacizumab blocks the effects of vascular endothelial growth factor in leakage-prone capillaries and has been suggested as a new treatment for cerebral radiation edema and necrosis. CyberKnife is a new, frameless stereotactic radiosurgery system. This work investigated the safety and efficacy of CyberKnife followed by early bevacizumab treatment for brain metastasis with extensive cerebral edema. The eligibility criteria of the patients selected for radiosurgery followed by early use of adjuvant bevacizumab treatment were: (1) brain tumors from metastasis with one solitary brain lesion and symptomatic extensive cerebral edema; (2) >18 years of age; (3) the patient refused surgery due to the physical conditions and the risk of surgery; (4) no contraindications for bevacizumab. (5) bevacizumab was applied for a minimum of 2 injections and a maximum of 6 injections with a 2-week interval between treatments, beginning within 2 weeks of the CyberKnife therapy; (6) Karnofsky performance status (KPS) ≥30. Tumor size and edema were monitored by magnetic resonance imaging (MRI). Dexamethasone dosage, KPS, adverse event occurrence and associated clinical outcomes were also recorded. Eight patients were accrued for this new treatment. Radiation dose ranged from 20 to 33 Gy in one to five sessions, prescribed to the 61-71 % isodose line. Bevacizumab therapy was administered 3-10 days after completion of CyberKnife treatment for a minimum of two cycles (5 mg/kg, at 2-week intervals). MRI revealed average reductions of 55.8 % (post-gadolinium) and 63.4 % (T2/FLAIR). Seven patients showed significant clinical neurological improvements. Dexamethasone was reduced in all patients, with five successfully discontinuing dexamethasone treatment 4 weeks after bevacizumab initiation. Hypertension, a bevacizumab-related adverse event, occurred in one patient. After 3-8 months, all patients studied were alive and primary brain metastases were under control, 2 developed new brain

  16. Stereotactic radiosurgery for vestibular schwannoma: International Stereotactic Radiosurgery Society (ISRS) Practice Guideline.

    PubMed

    Tsao, May N; Sahgal, Arjun; Xu, Wei; De Salles, Antonio; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Martinez, Roberto; Régis, Jean; Ryu, Sam; Slotman, Ben J; Paddick, Ian

    2017-01-01

    The aim of this systematic review was to develop International Stereotactic Radiosurgery Society (ISRS) consensus guideline statements for vestibular schwannoma. A systematic review of the literature was performed up to April 2015. A total of 55 full-text articles were included in the analysis. All studies were retrospective, except for 2 prospective quality of life studies. Five-year tumour control rates with Gamma Knife radiosurgery (RS), single fraction linac RS, or fractionated (either hypofractionated or conventional fractionation) stereotactic radiation therapy (FSRT) were similar at 81-100%. The single fraction RS series (linac or Gamma Knife) with tumour marginal doses between 12 and 14 Gy revealed 5-year tumour control rates of 90-99%, hearing preservation rates of 41-79%, facial nerve preservation rates of 95-100% and trigeminal preservation rates of 79-99%.There were 6 non-randomized studies comparing single fraction RS versus FSRT. There was no statistically significant difference in tumour control; HR=1.66 (95% CI 0.81, 3.42), p =0.17, facial nerve function; HR = 0.67 (95% CI 0.30, 1.49), p =0.33, trigeminal nerve function; HR = 0.80 (95% CI 0.41, 1.56), p =0.51, and hearing preservation; HR = 1.10 (95% CI 0.72, 1.68), p =0.65 comparing single fraction RS with FSRT.Nine quality of life reports yielded conflicting results as to which modality (surgery, observation, or radiation) was associated with better quality of life outcomes. There are no randomized trials to help guide management of patients with vestibular schwannoma. Within the limitations of the retrospective series, a number of consensus statements were made.

  17. Stereotactic radiosurgery for vestibular schwannoma: International Stereotactic Radiosurgery Society (ISRS) Practice Guideline

    PubMed Central

    Sahgal, Arjun; Xu, Wei; De Salles, Antonio; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Martinez, Roberto; Régis, Jean; Ryu, Sam; Slotman, Ben J.; Paddick, Ian

    2017-01-01

    Objectives The aim of this systematic review was to develop International Stereotactic Radiosurgery Society (ISRS) consensus guideline statements for vestibular schwannoma. Methods A systematic review of the literature was performed up to April 2015. Results A total of 55 full-text articles were included in the analysis. All studies were retrospective, except for 2 prospective quality of life studies. Five-year tumour control rates with Gamma Knife radiosurgery (RS), single fraction linac RS, or fractionated (either hypofractionated or conventional fractionation) stereotactic radiation therapy (FSRT) were similar at 81-100%. The single fraction RS series (linac or Gamma Knife) with tumour marginal doses between 12 and 14 Gy revealed 5-year tumour control rates of 90-99%, hearing preservation rates of 41-79%, facial nerve preservation rates of 95-100% and trigeminal preservation rates of 79-99%. There were 6 non-randomized studies comparing single fraction RS versus FSRT. There was no statistically significant difference in tumour control; HR=1.66 (95% CI 0.81, 3.42), p =0.17, facial nerve function; HR = 0.67 (95% CI 0.30, 1.49), p =0.33, trigeminal nerve function; HR = 0.80 (95% CI 0.41, 1.56), p =0.51, and hearing preservation; HR = 1.10 (95% CI 0.72, 1.68), p =0.65 comparing single fraction RS with FSRT. Nine quality of life reports yielded conflicting results as to which modality (surgery, observation, or radiation) was associated with better quality of life outcomes. Conclusions There are no randomized trials to help guide management of patients with vestibular schwannoma. Within the limitations of the retrospective series, a number of consensus statements were made. PMID:29296459

  18. Advanced image fusion algorithms for Gamma Knife treatment planning. Evaluation and proposal for clinical use.

    PubMed

    Apostolou, N; Papazoglou, Th; Koutsouris, D

    2006-01-01

    Image fusion is a process of combining information from multiple sensors. It is a useful tool implemented in the treatment planning programme of Gamma Knife Radiosurgery. In this paper we evaluate advanced image fusion algorithms for Matlab platform and head images. We develop nine level grayscale image fusion methods: average, principal component analysis (PCA), discrete wavelet transform (DWT) and Laplacian, filter - subtract - decimate (FSD), contrast, gradient, morphological pyramid and a shift invariant discrete wavelet transform (SIDWT) method in Matlab platform. We test these methods qualitatively and quantitatively. The quantitative criteria we use are the Root Mean Square Error (RMSE), the Mutual Information (MI), the Standard Deviation (STD), the Entropy (H), the Difference Entropy (DH) and the Cross Entropy (CEN). The qualitative are: natural appearance, brilliance contrast, presence of complementary features and enhancement of common features. Finally we make clinically useful suggestions.

  19. Comparison of penumbra regions produced by ancient Gamma knife model C and Gamma ART 6000 using Monte Carlo MCNP6 simulation.

    PubMed

    Banaee, Nooshin; Asgari, Sepideh; Nedaie, Hassan Ali

    2018-07-01

    The accuracy of penumbral measurements in radiotherapy is pivotal because dose planning computers require accurate data to adequately modeling the beams, which in turn are used to calculate patient dose distributions. Gamma knife is a non-invasive intracranial technique based on principles of the Leksell stereotactic system for open deep brain surgeries, invented and developed by Professor Lars Leksell. The aim of this study is to compare the penumbra widths of Leksell Gamma Knife model C and Gamma ART 6000. Initially, the structure of both systems were simulated by using Monte Carlo MCNP6 code and after validating the accuracy of simulation, beam profiles of different collimators were plotted. MCNP6 beam profile calculations showed that the penumbra values of Leksell Gamma knife model C and Gamma ART 6000 for 18, 14, 8 and 4 mm collimators are 9.7, 7.9, 4.3, 2.6 and 8.2, 6.9, 3.6, 2.4, respectively. The results of this study showed that since Gamma ART 6000 has larger solid angle in comparison with Gamma Knife model C, it produces better beam profile penumbras than Gamma Knife model C in the direct plane. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Radiosurgery of Glomus Jugulare Tumors: A Meta-Analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guss, Zachary D.; Batra, Sachin; Limb, Charles J.

    2011-11-15

    Purpose: During the past two decades, radiosurgery has arisen as a promising approach to the management of glomus jugulare. In the present study, we report on a systematic review and meta-analysis of the available published data on the radiosurgical management of glomus jugulare tumors. Methods and Materials: To identify eligible studies, systematic searches of all glomus jugulare tumors treated with radiosurgery were conducted in major scientific publication databases. The data search yielded 19 studies, which were included in the meta-analysis. The data from 335 glomus jugulare patients were extracted. The fixed effects pooled proportions were calculated from the data whenmore » Cochrane's statistic was statistically insignificant and the inconsistency among studies was <25%. Bias was assessed using the Egger funnel plot test. Results: Across all studies, 97% of patients achieved tumor control, and 95% of patients achieved clinical control. Eight studies reported a mean or median follow-up time of >36 months. In these studies, 95% of patients achieved clinical control and 96% achieved tumor control. The gamma knife, linear accelerator, and CyberKnife technologies all exhibited high rates of tumor and clinical control. Conclusions: The present study reports the results of a meta-analysis for the radiosurgical management of glomus jugulare. Because of its high effectiveness, we suggest considering radiosurgery for the primary management of glomus jugulare tumors.« less

  1. Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

    PubMed

    Yahya, S; Heyes, G; Nightingale, P; Lamin, S; Chavda, S; Geh, I; Spooner, D; Cruickshank, G; Sanghera, P

    2017-04-01

    Arteriovenous malformations (AVMs) are the leading causing of intra-cerebral haemorrhage. Stereotactic radiosurgery (SRS) is an established treatment for arteriovenous malformations (AVM) and commonly delivered using Gamma Knife within dedicated radiosurgery units. Linear accelerator (LINAC) SRS is increasingly available however debate remains over whether it offers an equivalent outcome. The aim of this project is to evaluate the outcomes using LINAC SRS for AVMs used within a UK neurosciences unit and review the literature to aid decision making across various SRS platforms. Results have shown comparability across platforms and strongly supports that an adapted LINAC based SRS facility within a dynamic regional neuro-oncology department delivers similar outcomes (in terms of obliteration and toxicity) to any other dedicated radio-surgical platform. Locally available facilities can facilitate discussion between options however throughput will inevitably be lower than centrally based dedicated national radiosurgery units. Copyright © 2016. Published by Elsevier Ltd.

  2. Radiosurgery alone for 5 or more brain metastases: expert opinion survey.

    PubMed

    Knisely, Jonathan P S; Yamamoto, Masaaki; Gross, Cary P; Castrucci, William A; Jokura, Hidefumi; Chiang, Veronica L S

    2010-12-01

    Oligometastatic brain metastases may be treated with stereotactic radiosurgery (SRS) alone, but no consensus exists as to when SRS alone would be appropriate. A survey was conducted at 2 radiosurgery meetings to determine which factors SRS practitioners emphasize in recommending SRS alone, and what physician characteristics are associated with recommending SRS alone for ≥ 5 metastases. All physicians attending the 8th Biennial Congress and Exhibition of the International Stereotactic Radiosurgery Society in June 2007 and the 18th Annual Meeting of the Japanese Society of Stereotactic Radiosurgery in July 2009 were asked to complete a questionnaire ranking 14 clinical factors on a 5-point Likert-type scale (ranging from 1 = not important to 5 = very important) to determine how much each factor might influence a decision to recommend SRS alone for brain metastases. Results were condensed into a single dichotomous outcome variable of "influential" (4-5) versus "not influential" (1-3). Respondents were also asked to complete the statement: "In general, a reasonable number of brain metastases treatable by SRS alone would be, at most, ___." The characteristics of physicians willing to recommend SRS alone for ≥ 5 metastases were assessed. Chi-square was used for univariate analysis, and logistic regression for multivariate analysis. The final study sample included 95 Gamma Knife and LINAC-using respondents (54% Gamma Knife users) in San Francisco and 54 in Sendai (48% Gamma Knife users). More than 70% at each meeting had ≥ 5 years experience with SRS. Sixty-five percent in San Francisco and 83% in Sendai treated ≥ 30 cases annually with SRS. The highest number of metastases considered reasonable to treat with SRS alone in both surveys was 50. In San Francisco, the mean and median numbers of metastases considered reasonable to treat with SRS alone were 6.7 and 5, while in Sendai they were 11 and 10. In the San Francisco sample, the clinical factors identified to be

  3. Automated medial axis seeding and guided evolutionary simulated annealing for optimization of gamma knife radiosurgery treatment plans

    NASA Astrophysics Data System (ADS)

    Zhang, Pengpeng

    The Leksell Gamma KnifeRTM (LGK) is a tool for providing accurate stereotactic radiosurgical treatment of brain lesions, especially tumors. Currently, the treatment planning team "forward" plans radiation treatment parameters while viewing a series of 2D MR scans. This primarily manual process is cumbersome and time consuming because the difficulty in visualizing the large search space for the radiation parameters (i.e., shot overlap, number, location, size, and weight). I hypothesize that a computer-aided "inverse" planning procedure that utilizes tumor geometry and treatment goals could significantly improve the planning process and therapeutic outcome of LGK radiosurgery. My basic observation is that the treatment team is best at identification of the location of the lesion and prescribing a lethal, yet safe, radiation dose. The treatment planning computer is best at determining both the 3D tumor geometry and optimal LGK shot parameters necessary to deliver a desirable dose pattern to the tumor while sparing adjacent normal tissue. My treatment planning procedure asks the neurosurgeon to identify the tumor and critical structures in MR images and the oncologist to prescribe a tumoricidal radiation dose. Computer-assistance begins with geometric modeling of the 3D tumor's medial axis properties. This begins with a new algorithm, a Gradient-Phase Plot (G-P Plot) decomposition of the tumor object's medial axis. I have found that medial axis seeding, while insufficient in most cases to produce an acceptable treatment plan, greatly reduces the solution space for Guided Evolutionary Simulated Annealing (GESA) treatment plan optimization by specifying an initial estimate for shot number, size, and location, but not weight. They are used to generate multiple initial plans which become initial seed plans for GESA. The shot location and weight parameters evolve and compete in the GESA procedure. The GESA objective function optimizes tumor irradiation (i.e., as close to

  4. Angiomatous lesion and delayed cyst formation after gamma knife surgery for intracranial meningioma: case report and review of literatures.

    PubMed

    Liu, Zhiyong; He, Min; Chen, Hongxu; Liu, Yi; Li, Qiang; Li, Lin; Li, Jin; Chen, Haifeng; Xu, Jianguo

    2015-01-01

    Gamma Knife has become a major therapeutic method for intracranial meningiomas, vascular malformations and schwannomas with exact effect. In recent years an increasing number of delayed complications after Gamma Knife surgery have been reported, such as secondary tumors, cystic changes or cyst formation. But angiomatous lesion and delayed cyst formation after Gamma Knife for intracranial lesion has rarely been reported. Here we report the first case of angiomatous lesion and delayed cyst formation following Gamma Knife for intracranial meningioma and discuss its pathogenesis.

  5. MCNP-based computational model for the Leksell gamma knife.

    PubMed

    Trnka, Jiri; Novotny, Josef; Kluson, Jaroslav

    2007-01-01

    We have focused on the usage of MCNP code for calculation of Gamma Knife radiation field parameters with a homogenous polystyrene phantom. We have investigated several parameters of the Leksell Gamma Knife radiation field and compared the results with other studies based on EGS4 and PENELOPE code as well as the Leksell Gamma Knife treatment planning system Leksell GammaPlan (LGP). The current model describes all 201 radiation beams together and simulates all the sources in the same time. Within each beam, it considers the technical construction of the source, the source holder, collimator system, the spherical phantom, and surrounding material. We have calculated output factors for various sizes of scoring volumes, relative dose distributions along basic planes including linear dose profiles, integral doses in various volumes, and differential dose volume histograms. All the parameters have been calculated for each collimator size and for the isocentric configuration of the phantom. We have found the calculated output factors to be in agreement with other authors' works except the case of 4 mm collimator size, where averaging over the scoring volume and statistical uncertainties strongly influences the calculated results. In general, all the results are dependent on the choice of the scoring volume. The calculated linear dose profiles and relative dose distributions also match independent studies and the Leksell GammaPlan, but care must be taken about the fluctuations within the plateau, which can influence the normalization, and accuracy in determining the isocenter position, which is important for comparing different dose profiles. The calculated differential dose volume histograms and integral doses have been compared with data provided by the Leksell GammaPlan. The dose volume histograms are in good agreement as well as integral doses calculated in small calculation matrix volumes. However, deviations in integral doses up to 50% can be observed for large

  6. SU-E-J-240: The Impact On Clinical Dose-Distributions When Using MR-Images Registered with Stereotactic CT-Images in Gamma Knife Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Benmakhlouf, H; Kraepelien, T; Forander, P

    2014-06-01

    Purpose: Most Gamma knife treatments are based solely on MR-images. However, for fractionated treatments and to implement TPS dose calculations that require electron densities, CT image data is essential. The purpose of this work is to assess the dosimetric effects of using MR-images registered with stereotactic CT-images in Gamma knife treatments. Methods: Twelve patients treated for vestibular schwannoma with Gamma Knife Perfexion (Elekta Instruments, Sweden) were selected for this study. The prescribed doses (12 Gy to periphery) were delivered based on the conventional approach of using stereotactic MR-images only. These plans were imported into stereotactic CT-images (by registering MR-images withmore » stereotactic CT-images using the Leksell gamma plan registration software). The dose plans, for each patient, are identical in both cases except for potential rotations and translations resulting from the registration. The impact of the registrations was assessed by an algorithm written in Matlab. The algorithm compares the dose-distributions voxel-by-voxel between the two plans, calculates the full dose coverage of the target (treated in the conventional approach) achieved by the CT-based plan, and calculates the minimum dose delivered to the target (treated in the conventional approach) achieved by the CT-based plan. Results: The mean dose difference between the plans was 0.2 Gy to 0.4 Gy (max 4.5 Gy) whereas between 89% and 97% of the target (treated in the conventional approach) received the prescribed dose, by the CT-plan. The minimum dose to the target (treated in the conventional approach) given by the CT-based plan was between 7.9 Gy and 10.7 Gy (compared to 12 Gy in the conventional treatment). Conclusion: The impact of using MR-images registered with stereotactic CT-images has successfully been compared to conventionally delivered dose plans showing significant differences between the two. Although CTimages have been implemented clinically; the

  7. Situated cognition in clinical visualization: the role of transparency in GammaKnife neurosurgery planning.

    PubMed

    Dinka, David; Nyce, James M; Timpka, Toomas

    2009-06-01

    The aim of this study was to investigate how the clinical use of visualization technology can be advanced by the application of a situated cognition perspective. The data were collected in the GammaKnife radiosurgery setting and analyzed using qualitative methods. Observations and in-depth interviews with neurosurgeons and physicists were performed at three clinics using the Leksell GammaKnife. The users' ability to perform cognitive tasks was found to be reduced each time visualizations incongruent with the particular user's perception of clinical reality were used. The main issue here was a lack of transparency, i.e. a black box problem where machine representations "stood between" users and the cognitive tasks they wanted to perform. For neurosurgeons, transparency meant their previous experience from traditional surgery could be applied, i.e. that they were not forced to perform additional cognitive work. From the view of the physicists, on the other hand, the concept of transparency was associated with mathematical precision and avoiding creating a cognitive distance between basic patient data and what is experienced as clinical reality. The physicists approached clinical visualization technology as though it was a laboratory apparatus--one that required continual adjustment and assessment in order to "capture" a quantitative clinical reality. Designers of visualization technology need to compare the cognitive interpretations generated by the new visualization systems to conceptions generated during "traditional" clinical work. This means that the viewpoint of different clinical user groups involved in a given clinical task would have to be taken into account as well. A way forward would be to acknowledge that visualization is a socio-cognitive function that has practice-based antecedents and consequences, and to reconsider what analytical and scientific challenges this presents us with.

  8. OUT-OF-FIELD DOSES IN CHILDREN TREATED FOR LARGE ARTERIOVENOUS MALFORMATIONS USING HYPOFRACTIONATED GAMMA KNIFE RADIOSURGERY AND INTENSITY-MODULATED RADIATION THERAPY.

    PubMed

    De Saint-Hubert, Marijke; Majer, Marija; Hršak, Hrvoje; Heinrich, Zdravko; Kneževic, Željka; Miljanic, Saveta; Porwol, Paulina; Stolarczyk, Liliana; Vanhavere, Filip; Harrison, Roger M

    2018-01-17

    The purpose of this study was to measure out-of-field organ doses in two anthropomorphic child phantoms for the treatment of large brain arteriovenous malformations (AVMs) using hypofractionated gamma knife (GK) radiosurgery and to compare these with an alternative treatment using intensity-modulated radiation therapy (IMRT). Target volume was identical in size and shape in all cases. Radiophotoluminescent (RPL), thermoluminescent (TL) and optically stimulated luminescent (OSL) dosimeters were used for out-of-field dosimetry during GK treatment and a good agreement within 1-2% between results was shown. In addition, the use of multiple dosimetry systems strengthens the reliability of the findings. The number of GK isocentres was confirmed to be important for the magnitude of out-of-field doses. Measured GK doses for the same distance from the target, when expressed per target dose and isocentre, were comparable in both phantoms. GK out-of-field doses averaged for both phantoms were evaluated to be 120 mGy/Gy for eyes then sharply reduced to 20 mGy/Gy for mandible and slowly reduced up to 0.8 mGy/Gy for testes. Taking into account the fractionation regimen used to treat AVM patients, the total treatment organ doses to the out-of-field organs were calculated and compared with IMRT. The eyes were better spared with GK whilst for more distant organs doses were up to a factor of 2.8 and 4 times larger for GK compared to IMRT in 5-year and 10-year old phantoms, respectively. Presented out-of-field dose values are specific for the investigated AVM case, phantoms and treatment plans used for GK and IMRT, but provide useful information about out-of-field dose levels and emphasise their importance. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. A fully automatic approach for multimodal PET and MR image segmentation in gamma knife treatment planning.

    PubMed

    Rundo, Leonardo; Stefano, Alessandro; Militello, Carmelo; Russo, Giorgio; Sabini, Maria Gabriella; D'Arrigo, Corrado; Marletta, Francesco; Ippolito, Massimo; Mauri, Giancarlo; Vitabile, Salvatore; Gilardi, Maria Carla

    2017-06-01

    Nowadays, clinical practice in Gamma Knife treatments is generally based on MRI anatomical information alone. However, the joint use of MRI and PET images can be useful for considering both anatomical and metabolic information about the lesion to be treated. In this paper we present a co-segmentation method to integrate the segmented Biological Target Volume (BTV), using [ 11 C]-Methionine-PET (MET-PET) images, and the segmented Gross Target Volume (GTV), on the respective co-registered MR images. The resulting volume gives enhanced brain tumor information to be used in stereotactic neuro-radiosurgery treatment planning. GTV often does not match entirely with BTV, which provides metabolic information about brain lesions. For this reason, PET imaging is valuable and it could be used to provide complementary information useful for treatment planning. In this way, BTV can be used to modify GTV, enhancing Clinical Target Volume (CTV) delineation. A novel fully automatic multimodal PET/MRI segmentation method for Leksell Gamma Knife ® treatments is proposed. This approach improves and combines two computer-assisted and operator-independent single modality methods, previously developed and validated, to segment BTV and GTV from PET and MR images, respectively. In addition, the GTV is utilized to combine the superior contrast of PET images with the higher spatial resolution of MRI, obtaining a new BTV, called BTV MRI . A total of 19 brain metastatic tumors, undergone stereotactic neuro-radiosurgery, were retrospectively analyzed. A framework for the evaluation of multimodal PET/MRI segmentation is also presented. Overlap-based and spatial distance-based metrics were considered to quantify similarity concerning PET and MRI segmentation approaches. Statistics was also included to measure correlation among the different segmentation processes. Since it is not possible to define a gold-standard CTV according to both MRI and PET images without treatment response assessment

  10. TU-D-207B-01: A Prediction Model for Distinguishing Radiation Necrosis From Tumor Progression After Gamma Knife Radiosurgery Based On Radiomics Features From MR Images

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang, Z; MD Anderson Cancer Center, Houston, TX; Ho, A

    Purpose: To develop and validate a prediction model using radiomics features extracted from MR images to distinguish radiation necrosis from tumor progression for brain metastases treated with Gamma knife radiosurgery. Methods: The images used to develop the model were T1 post-contrast MR scans from 71 patients who had had pathologic confirmation of necrosis or progression; 1 lesion was identified per patient (17 necrosis and 54 progression). Radiomics features were extracted from 2 images at 2 time points per patient, both obtained prior to resection. Each lesion was manually contoured on each image, and 282 radiomics features were calculated for eachmore » lesion. The correlation for each radiomics feature between two time points was calculated within each group to identify a subset of features with distinct values between two groups. The delta of this subset of radiomics features, characterizing changes from the earlier time to the later one, was included as a covariate to build a prediction model using support vector machines with a cubic polynomial kernel function. The model was evaluated with a 10-fold cross-validation. Results: Forty radiomics features were selected based on consistent correlation values of approximately 0 for the necrosis group and >0.2 for the progression group. In performing the 10-fold cross-validation, we narrowed this number down to 11 delta radiomics features for the model. This 11-delta-feature model showed an overall prediction accuracy of 83.1%, with a true positive rate of 58.8% in predicting necrosis and 90.7% for predicting tumor progression. The area under the curve for the prediction model was 0.79. Conclusion: These delta radiomics features extracted from MR scans showed potential for distinguishing radiation necrosis from tumor progression. This tool may be a useful, noninvasive means of determining the status of an enlarging lesion after radiosurgery, aiding decision-making regarding surgical resection versus conservative

  11. Gamma Knife surgery for intracranial chordoma and chondrosarcoma: radiosurgical perspectives and treatment outcomes.

    PubMed

    Kim, Ji Hee; Jung, Hyun Ho; Chang, Jong Hee; Chang, Jin Woo; Park, Yong Gou; Chang, Won Seok

    2014-12-01

    Intracranial chordomas and chondrosarcomas are histologically low-grade, locally invasive tumors that are reported to be similar in terms of anatomical location, clinical presentation, and radiological findings but different in terms of behavior and outcomes. The purpose of this study was to investigate and compare clinical outcomes after Gamma Knife surgery (GKS) for the treatment of intracranial chordoma and chondrosarcoma. The authors conducted a retrospective review of the results of radiosurgical treatment of intracranial chordomas and chondrosarcomas. They enrolled patients who had undergone GKS for intracranial chordoma or chondrosarcoma at the Yonsei Gamma Knife Center, Yonsei University College of Medicine, from October 2000 through June 2007. Analyses included only patients for whom the disease was pathologically diagnosed before GKS and for whom more than 5 years of follow-up data after GKS were available. Rates of progression-free survival and overall survival were analyzed and compared according to tumor pathology. Moreover, the association between tumor control and the margin radiation dose to the tumor was analyzed, and the rate of tumor volume change after GKS was quantified. A total of 10 patients were enrolled in this study. Of these, 5 patients underwent a total of 8 sessions of GKS for chordoma, and the other 5 patients underwent a total of 7 sessions of GKS for chondrosarcoma. The 2- and 5-year progression-free survival rates for patients in the chordoma group were 70% and 35%, respectively, and rates for patients in the chondrosarcoma group were 100% and 80%, respectively (log-rank test, p = 0.04). The 2- and 5-year overall survival rates after GKS for patients in the chordoma group were 87.5% and 72.9%, respectively, and rates for patients in the chondrosarcoma group were 100% and 100%, respectively (log-rank test, p = 0.03). The mean rates of tumor volume change 2 years after radiosurgery were 79.64% and 39.91% for chordoma and

  12. CyberKnife Radiosurgery in the Multimodal Management of Patients with Cushing Disease.

    PubMed

    Moore, Justin M; Sala, Elisa; Amorin, Alvaro; Martinez, Hector; Bhowmik, Aprotim C; Chang, Steven D; Soltys, Scott G; Harsh, Griffith R; Katznelson, Laurence

    2018-04-01

    Surgery is the primary treatment for Cushing disease. When surgery is unsuccessful in normalizing hypercortisolism, adjuvant radiation, such as stereotactic radiosurgery, may be useful to improve biochemical control. This retrospective study included a cohort of consecutive patients treated with CyberKnife (CK) radiosurgery for active Cushing disease at Stanford Hospital and Clinics. As first-line treatment, all patients underwent transsphenoidal surgery with histologic demonstration of an adrenocorticotropic hormone-producing pituitary adenoma. CK was performed as adjuvant therapy for persistent or recurrent disease. The median time between surgery and CK was 14 ± 34 months. Before CK, median maximal diameter of tumors was 9 mm (range, 7-32 mm), with cavernous sinus invasion in all patients (100%) and abutment of the optic chiasm in 1 patient (14.2%). With an average follow-up of 55.4 months, normalization of hypercortisolism was achieved in 4 patients (57.1%): 2 patients (28.5%) achieved normalization of the hypothalamic-pituitary-adrenal axis without glucocorticoid replacement, and 2 patients developed hypoadrenalism (28.5%). The median time to biochemical remission was 12.5 months. Hypopituitarism occurred in only 1 patient (14.2%), and no patients had visual complications. Time between surgery and radiotherapy of <14 months was associated with a significantly improved biochemical remission rate (P = 0.02). In a cohort of patients with Cushing disease, we demonstrate that CK is an effective treatment with rare complications. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. A comparison of the convolution and TMR10 treatment planning algorithms for Gamma Knife® radiosurgery

    PubMed Central

    Wright, Gavin; Harrold, Natalie; Bownes, Peter

    2018-01-01

    Aims To compare the accuracies of the convolution and TMR10 Gamma Knife treatment planning algorithms, and assess the impact upon clinical practice of implementing convolution-based treatment planning. Methods Doses calculated by both algorithms were compared against ionisation chamber measurements in homogeneous and heterogeneous phantoms. Relative dose distributions calculated by both algorithms were compared against film-derived 2D isodose plots in a heterogeneous phantom, with distance-to-agreement (DTA) measured at the 80%, 50% and 20% isodose levels. A retrospective planning study compared 19 clinically acceptable metastasis convolution plans against TMR10 plans with matched shot times, allowing novel comparison of true dosimetric parameters rather than total beam-on-time. Gamma analysis and dose-difference analysis were performed on each pair of dose distributions. Results Both algorithms matched point dose measurement within ±1.1% in homogeneous conditions. Convolution provided superior point-dose accuracy in the heterogeneous phantom (-1.1% v 4.0%), with no discernible differences in relative dose distribution accuracy. In our study convolution-calculated plans yielded D99% 6.4% (95% CI:5.5%-7.3%,p<0.001) less than shot matched TMR10 plans. For gamma passing criteria 1%/1mm, 16% of targets had passing rates >95%. The range of dose differences in the targets was 0.2-4.6Gy. Conclusions Convolution provides superior accuracy versus TMR10 in heterogeneous conditions. Implementing convolution would result in increased target doses therefore its implementation may require a revaluation of prescription doses. PMID:29657896

  14. Do Recent Advances in MR Technologies Contribute to Better Gamma Knife Radiosurgery Treatment Results for Brain Metastases?

    PubMed

    Hayashi, M; Yamamoto, M; Nishimura, C; Satoh, H

    2007-10-31

    The detection of intracerebral lesions has improved greatly with advancements in MR imaging, especially the greater sensitivity of the 1.5 Tesla unit versus the older 1.0 Tesla unit. We aimed to determine whether improvements in MR imaging have actually improved diagnostic capabilities and treatment outcomes in gamma knife radiosurgery (GKRS) for brain metastases (METs). Ours was a retrospective study of a consecutive series of 1179 patients (441 females, 738 males, mean age: 63 years, range: 19-92 years) with brain METs who underwent GKRS from 1998 to 2004. Our treatment policy was to irradiate all lesions visible on MR images during a single GKRS session. Mean and median tumor numbers were seven and three (range; 1-74). The 1179 patients were divided into two groups: a 1.0 T-group of 660 patients examined using a 1.0 Tesla MR unit before August,2002, and a 1.5 T-group of 519 examined using a 1.5 Tesla MR unit after September 2002. In the 1.5 T-group, lesion volumes as small as 0.004 cc were detected with a 5 mm slice thickness. The corresponding lesion size was 0.013 cc in the 1.0 T-group. One or more lesions invisible on a 5 mm slice study were additionally detected on a 2 mm slice study in 47.8% of patients in the 1.0 T-group and 25.2% in the 1.5 T-group (p<.0001). The median survival time (MST) in the 1.5 T-group was significantly longer than that in the 1.0 T-group (8.4 vs. 6.3 months, p=.0004). Due to biases in patient numbers between the two groups, we analyzed subgroups with KPS of 80% or better, no neurological deficits, stable primary tumors, lung cancer, tumor numbers of four or less and tumor volumes of 10.0 cc or smaller. In every subgroup analysis, the MSTs of the 1.5-Tesla group were significantly longer than those of the 1.0-Tesla group. The prognosis of a cancer patient is undoubtedly influenced by multiple factors. Nevertheless, we conclude that application of the 1.5 Tesla MR unit has had a favorable impact on diagnosis and GKRS treatment

  15. Stereotaxic gamma knife surgery in treatment of critically located pilocytic astrocytoma: preliminary result

    PubMed Central

    Hafez, Raef FA

    2007-01-01

    Background Low-grade gliomas are uncommon primary brain tumors, located more often in the posterior fossa, optic pathway, and brain stem and less commonly in the cerebral hemispheres. Case presentations Two patients with diagnosed recurrent cystic pilocytic astrocytoma critically located within the brain (thalamic and brain stem) were treated with gamma knife surgery. Gamma knife surgery (GKS) did improve the patient's clinical condition very much which remained stable later on. Progressive reduction on the magnetic resonance imaging (MRI) studies of the solid part of the tumor and almost disappearance of the cystic component was achieved within the follow-up period of 36 months in the first case with the (thalamic located lesion) and 22 months in the second case with the (brain stem located lesion). Conclusion Gamma knife surgery represents an alternate tool in the treatment of recurrent and/or small postoperative residual pilocytic astrocytoma especially if they are critically located PMID:17394660

  16. Usefulness of the advanced neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state images for gamma knife radiosurgery and planning microsurgical procedures for skull base tumors.

    PubMed

    Hayashi, Motohiro; Chernov, Mikhail F; Tamura, Noriko; Yomo, Shoji; Tamura, Manabu; Horiba, Ayako; Izawa, Masahiro; Muragaki, Yoshihiro; Iseki, Hiroshi; Okada, Yoshikazu; Ivanov, Pavel; Régis, Jean; Takakura, Kintomo

    2013-01-01

    Gamma Knife radiosurgery (GKS) is currently performed with 0.1 mm preciseness, which can be designated microradiosurgery. It requires advanced methods for visualizing the target, which can be effectively attained by a neuroimaging protocol based on plain and gadolinium-enhanced constructive interference in steady state (CISS) images. Since 2003, the following thin-sliced images are routinely obtained before GKS of skull base lesions in our practice: axial CISS, gadolinium-enhanced axial CISS, gadolinium-enhanced axial modified time-of-flight (TOF), and axial computed tomography (CT). Fusion of "bone window" CT and magnetic resonance imaging (MRI), and detailed three-dimensional (3D) delineation of the anatomical structures are performed with the Leksell GammaPlan (Elekta Instruments AB). Recently, a similar technique has been also applied to evaluate neuroanatomy before open microsurgical procedures. Plain CISS images permit clear visualization of the cranial nerves in the subarachnoid space. Gadolinium-enhanced CISS images make the tumor "lucid" but do not affect the signal intensity of the cranial nerves, so they can be clearly delineated in the vicinity to the lesion. Gadolinium-enhanced TOF images are useful for 3D evaluation of the interrelations between the neoplasm and adjacent vessels. Fusion of "bone window" CT and MRI scans permits simultaneous assessment of both soft tissue and bone structures and allows 3D estimation and correction of MRI distortion artifacts. Detailed understanding of the neuroanatomy based on application of the advanced neuroimaging protocol permits performance of highly conformal and selective radiosurgical treatment. It also allows precise planning of the microsurgical procedures for skull base tumors.

  17. Optimal Shape of a Gamma-ray Collimator: single vs double knife edge

    NASA Astrophysics Data System (ADS)

    Metz, Albert; Hogenbirk, Alfred

    2017-09-01

    Gamma-ray collimators in nuclear waste scanners are used for selecting a narrow vertical segment in activity measurements of waste vessels. The system that is used by NRG uses tapered slit collimators of both the single and double knife edge type. The properties of these collimators were investigated by means of Monte Carlo simulations. We found that single knife edge collimators are highly preferable for a conservative estimate of the activity of the waste vessels. These collimators show much less dependence on the angle of incidence of the radiation than double knife edge collimators. This conclusion also applies to cylindrical collimators of the single knife edge type, that are generally used in medical imaging spectroscopy.

  18. 10 CFR 35.2645 - Records of periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... radiosurgery units. 35.2645 Section 35.2645 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT...'s name, model number, and serial number for the gamma stereotactic radiosurgery unit and the... and localizing devices (trunnions); and (9) The name of the individual who performed the periodic spot...

  19. 10 CFR 35.2645 - Records of periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... radiosurgery units. 35.2645 Section 35.2645 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT...'s name, model number, and serial number for the gamma stereotactic radiosurgery unit and the... and localizing devices (trunnions); and (9) The name of the individual who performed the periodic spot...

  20. SU-D-BRB-04: Plan Quality Comparison of Intracranial Stereotactic Radiosurgery (SRS) for Gamma Knife and VMAT Treatments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Keeling, V; Algan, O; Ahmad, S

    2015-06-15

    Purpose: To compare treatment plan quality of intracranial stereotactic radiosurgery (SRS) for VMAT (RapidArc) and Gamma Knife (GK) systems. Methods: Ten patients with 24 tumors (seven with 1–2 and three with 4–6 lesions), previously treated with GK 4C (prescription doses ranging from 14–23 Gy) were re-planned for RapidArc. Identical contour sets were kept on MRI images for both plans with tissues assigned a CT number of zero. RapidArc plans were performed using 6 MV flattening-filter-free (FFF) beams with dose rate of 1400 MU/minute using two to eight arcs with the following combinations: 2 full coplanar arcs and the rest non-coplanarmore » half arcs. Beam selection was based on target depth. Areas that penetrated more than 10 cm of tissue were avoided by creating smaller arcs or using avoidance sectors in optimization. Plans were optimized with jaw tracking and a high weighting to the normal-brain-tissue and Normal-Tissue-Objective without compromising PTV coverage. Plans were calculated on a 1 mm grid size using AAA algorithm and then normalized so that 99% of each target volume received the prescription dose. Plan quality was assessed by target coverage using Paddick Conformity Index (PCI), sparing of normal-brain-tissue through analysis of V4, V8, and V12 Gy, and integral dose. Results: In all cases critical structure dose criteria were met. RapidArc had a higher PCI than GK plans for 23 out of 24 lesions. The average PCI was 0.76±0.21 for RapidArc and 0.46±0.20 for GK plans (p≤0.001), respectively. Integral dose and normal-brain-tissue doses for all criteria were lower for RapidArc in nearly all patients. The average ratio of GK to RapidArc plans was 1.28±0.27 (p=0.018), 1.31±0.25 (p=0.017), 1.81±0.43 (p=0.005), and 1.50±0.61 (p=0.006) for V4, V8, and V12 Gy, and integral dose, respectively. Conclusion: VMAT was capable of producing higher quality treatment plans than GK when using optimal beam geometries and proper optimization techniques.« less

  1. Radiosurgery for Arteriovenous Malformations and the Impact on Headaches.

    PubMed

    Bowden, Greg; Cavaleri, Jonathon; Kano, Hideyuki; Monaco, Edward; Niranjan, Ajay; Flickinger, John; Dade Lunsford, L

    2017-05-01

    Arteriovenous malformations (AVMs) can underlie many diverse neurological signs and symptoms. Headaches are a common presentation that can have a significant impact on quality of life. The authors investigated Gamma Knife ® stereotactic radiosurgery (SRS) outcomes in patients with AVMs and associated headaches. This retrospective study analyzed 102 patients with AVMs who underwent SRS between 1995 and 2013. The patient's headache symptoms led to their AVM diagnosis or developed post hemorrhage of their AVM. Information regarding headache characteristics was obtained from the patient's medical records and at follow-up using a scripted clinical interview. The median imaging follow-up was 61.7 months and clinical follow-up was 89.7 months. The median treatment volume at SRS was 4.1 cm 3 and the median marginal dose was 20 Gy. The actuarial AVM obliteration rate was 60% at 5 years and 78% at 10 years. Patients reported that their overall headache severity decreased by -43.6% and their headache frequency was reduced by -53.4%. Headache reduction was reported in 49.1% of patients at 1 year and 69.5% at 5 years. The median time until improvement was 6.5 months. After SRS, headache medication usage decreased in 29% of patients. Permanent adverse radiation effects after SRS occurred in 3% of patients. Until obliteration was complete, the annual risk of a hemorrhage after SRS was 0.4% per year. Although recall bias related to a retrospective analysis can impact outcomes, headache symptoms associated with AVMs may potentially be decreased or eliminated in a subset of patients treated with Gamma Knife radiosurgery. © 2017 American Headache Society.

  2. Grading of vestibular schwannomas and corresponding tumor volumes: ramifications for radiosurgery.

    PubMed

    Mindermann, T; Schlegel, I

    2013-01-01

    Patients with vestibular schwannomas (VS) are either assigned to watchful waiting, microsurgical resection, or radiosurgery. Decision making on how to proceed is based on parameters such as age, tumor growth, loss of hearing, and the tumor's Koos grading. In order to correlate Koos grading with tumor volume, patient records of 235 patients with VS who underwent Gamma Knife radiosurgery (GKRS) were retrospectively reviewed. From 1994 to 2009, 235 consecutive patients underwent GKRS for sporadic VS at the Zurich Gamma Knife Center. Median follow up was 62.8 ± 33.0 months. Of the 235 tumors, 32 (13.6 %) were graded Koos I with a volume of 0.25 ± 0.3 cc; 71 (30.2 %) were graded Koos II with a volume of 0.57 ± 0.54 cc; 70 (29.8 %) were graded Koos III with a volume of 1.82 ± 1.88 cc; and 62 (26.4 %) were graded Koos IV with a volume of 4.17 ± 2.75 cc. Tumor progression was defined as a volume increase > 20 % at 2 years or later following GKRS. Overall tumor progression occurred in 21/235 (8.9 %) patients at 3.4 ± 0.9 years. Tumor progression did not differ statistically significantly in the various Koos grades: 1/32 (3.1 %) patients with VS Koos Grade I, 7/71 (9.8 %) patients with VS Koos Grade II, 6/70 (8.6 %) patients with VS Koos Grade III, and 7/62 (11.3 %) patients with VS Koos Grade IV. To our knowledge, this is the first work correlating the various Koos grades of VS to their respective tumor volumes. In our patients, tumor volumes of VS Koos Grade IV were limited because all of our patients were eligible for radiosurgery. In our series, the outcome following GKRS for patients with VS Koos Grade IV tumors did not differ from patients with VS Koos Grades I-III. We therefore suggest to limit Koos Grade IV VS to tumor volumes < 6 cc that may be eligible for radiosurgery, and introduce an additional VS Grade V for large VS with tumor volumes of > 6 cc that may not be eligible for radiosurgery.

  3. Stereotactic radiosurgery for the treatment of mesial temporal lobe epilepsy.

    PubMed

    Feng, E-S; Sui, C-B; Wang, T-X; Sun, G-L

    2016-12-01

    Stereotactic radiosurgery (RS) is a potential option for some patients with temporal lobe epilepsy (TLE). The aim of this meta-analysis was to determine the pooled seizure-free rate and the time interval to seizure cessation in patients with lesions in the mesial temporal lobe, and who were eligible for either stereotactic or gamma knife RS. We searched the Medline, Cochrane, EMBASE, and Google Scholar databases using combinations of the following terms: RS, stereotactic radiosurgery, gamma knife, and TLE. We screened 103 articles and selected 13 for inclusion in the meta-analysis. Significant study heterogeneity was detected; however, the included studies displayed an acceptable level of quality. We show that approximately half of the patients were seizure free over a follow-up period that ranged from 6 months to 9 years [pooled estimate: 50.9% (95% confidence interval: 0.381-0.636)], with an average of 14 months to seizure cessation [pooled estimate: 14.08 months (95% confidence interval: 11.95-12.22 months)]. Nine of 13 included studies reported data for adverse events (AEs), which included visual field deficits and headache (the two most common AEs), verbal memory impairment, psychosis, psychogenic non-epileptic seizures, and dysphasia. Patients in the individual studies experienced AEs at rates that ranged from 8%, for non-epileptic seizures, to 85%, for headache. Our findings indicate that RS may have similar or slightly less efficacy in some patients compared with invasive surgery. Randomized controlled trials of both treatment regimens should be undertaken to generate an evidence base for patient decision-making. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Gamma knife radiosurgery for essential tremor: A Case report and review of the literature

    PubMed Central

    2010-01-01

    Approximately 5 million people in America are affected by essential tremors (ET), which are classified as a type of benign movement disorder. This disease manifests as tremors that usually occur in the hands, but they may also be present in the head, face, tongue, and lower limbs. Radiofrequency thalamotomy (RF) and deep brain stimulation (DBS) are common invasive procedures with proven track records that are used to treat ET. Although these procedures have high success rates, they still put patients at risk of potential side effects and are invasive by nature. Thalamotomy using the gamma knife (GK) also produces favorable outcomes in treating tremors, without the complications associated with invasive neurosurgery procedures. This report describes the presenting symptoms and extended treatment outcome for a patient with an advanced case of ET, who received GK thalamotomy treatment six years ago. Because of this non-invasive treatment, she regained the ability to paint and live with an improved quality of life. We also discuss and review the relevant literature regarding the risks and benefits of this treatment modality. GK thalamotomy is one effective option for the treatment of ET, and due to its noninvasive nature, it has a different risk profile than neurosurgery. We suggest that GK thalamotomy should be presented as one viable treatment option to all ET patients, and should be recommended to those who would be best served by less invasive treatment techniques. PMID:20307307

  5. Study Protocol: Early Stereotactic Gamma Knife Radiosurgery to Residual Tumor After Surgery of Newly Diagnosed Glioblastoma (Gamma-GBM).

    PubMed

    Brehmer, Stefanie; Grimm, Mario Alexander; Förster, Alex; Seiz-Rosenhagen, Marcel; Welzel, Grit; Stieler, Florian; Wenz, Frederik; Groden, Christoph; Mai, Sabine; Hänggi, Daniel; Giordano, Frank Anton

    2018-04-24

    Glioblastoma (GBM) is the most common malignant brain tumor in adult patients. Tumor recurrence commonly occurs around the resection cavity, especially after subtotal resection (STR). Consequently, the extent of resection correlates with overall survival (OS), suggesting that depletion of postoperative tumor remnants will improve outcome. To assess safety and efficacy of adding stereotactic radiosurgery (SRS) to the standard treatment of GBM in patients with postoperative residual tumor. Gamma-GBM is a single center, open-label, prospective, single arm, phase II study that includes patients with newly diagnosed GBM (intraoperative via frozen sections) who underwent STR (residual tumor will be identified by native and contrast enhanced T1-weighted magnetic resonance imaging scans). All patients will receive SRS with 15 Gy (prescribed to the 50% isodose enclosing all areas of residual tumor) early (within 24-72 h) after surgery. Thereafter, all patients undergo standard-of-care therapy for GBM (radiochemotherapy with 60 Gy external beam radiotherapy [EBRT] plus concomitant temozolomide and 6 cycles of adjuvant temozolomide chemotherapy). The primary outcome is median progression-free survival, secondary outcomes are median OS, occurrence of radiation induced acute (<3 wk), early delayed (<3 mo), and late (>3 mo post-SRS) neurotoxicity and incidence of symptomatic radionecrosis. We expect to detect efficacy and safety signals by the immediate application of SRS to standard-of-care therapy in newly diagnosed GBM. Early postoperative SRS to areas of residual tumor could bridge the therapeutic gap between surgery and adjuvant therapies.

  6. 10 CFR 35.655 - Five-year inspection for teletherapy and gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Five-year inspection for teletherapy and gamma stereotactic radiosurgery units. 35.655 Section 35.655 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  7. 10 CFR 35.655 - Five-year inspection for teletherapy and gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Five-year inspection for teletherapy and gamma stereotactic radiosurgery units. 35.655 Section 35.655 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  8. 10 CFR 35.655 - Five-year inspection for teletherapy and gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Five-year inspection for teletherapy and gamma stereotactic radiosurgery units. 35.655 Section 35.655 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  9. 10 CFR 35.655 - Five-year inspection for teletherapy and gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Five-year inspection for teletherapy and gamma stereotactic radiosurgery units. 35.655 Section 35.655 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  10. 10 CFR 35.655 - Five-year inspection for teletherapy and gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Five-year inspection for teletherapy and gamma stereotactic radiosurgery units. 35.655 Section 35.655 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  11. Stereotactic Radiosurgery for Cushing Disease: Results of an International, Multicenter Study.

    PubMed

    Mehta, Gautam U; Ding, Dale; Patibandla, Mohana Rao; Kano, Hideyuki; Sisterson, Nathaniel; Su, Yan-Hua; Krsek, Michal; Nabeel, Ahmed M; El-Shehaby, Amr; Kareem, Khaled A; Martinez-Moreno, Nuria; Mathieu, David; McShane, Brendan; Blas, Kevin; Kondziolka, Douglas; Grills, Inga; Lee, John Y; Martinez-Alvarez, Roberto; Reda, Wael A; Liscak, Roman; Lee, Cheng-Chia; Lunsford, L Dade; Vance, Mary Lee; Sheehan, Jason P

    2017-11-01

    Cushing disease (CD) due to adrenocorticotropic hormone-secreting pituitary tumors can be a management challenge. To better understand the outcomes of stereotactic radiosurgery (SRS) for CD and define its role in management. International, multicenter, retrospective cohort analysis. Ten medical centers participating in the International Gamma Knife Research Foundation. Patients with CD with >6 months endocrine follow-up. SRS using Gamma Knife radiosurgery. The primary outcome was control of hypercortisolism (defined as normalization of free urinary cortisol). Radiologic response and adverse radiation effects (AREs) were recorded. In total, 278 patients met inclusion criteria, with a mean follow-up of 5.6 years (0.5 to 20.5 years). Twenty-two patients received SRS as a primary treatment of CD. Mean margin dose was 23.7 Gy. Cumulative initial control of hypercortisolism was 80% at 10 years. Mean time to cortisol normalization was 14.5 months. Recurrences occurred in 18% with initial cortisol normalization. Overall, the rate of durable control of hypercortisolism was 64% at 10 years and 68% among patients who received SRS as a primary treatment. AREs included hypopituitarism (25%) and cranial neuropathy (3%). Visual deficits were related to treatment of tumor within the suprasellar cistern (P = 0.01), whereas both visual (P < 0.0001) and nonvisual cranial neuropathy (P = 0.02) were related to prior pituitary irradiation. SRS for CD is well tolerated and frequently results in control of hypercortisolism. However, recurrences can occur. SRS should be considered for patients with persistent hypercortisolism after pituitary surgery and as a primary treatment in those unfit for surgery. Long-term endocrine follow-up is essential after SRS. Copyright © 2017 Endocrine Society

  12. 10 CFR 35.2645 - Records of periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Records of periodic spot-checks for gamma stereotactic... MATERIAL Records § 35.2645 Records of periodic spot-checks for gamma stereotactic radiosurgery units. (a) A... and intercom systems, timer termination, treatment table retraction mechanism, and stereotactic frames...

  13. 10 CFR 35.2645 - Records of periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Records of periodic spot-checks for gamma stereotactic... MATERIAL Records § 35.2645 Records of periodic spot-checks for gamma stereotactic radiosurgery units. (a) A... and intercom systems, timer termination, treatment table retraction mechanism, and stereotactic frames...

  14. 10 CFR 35.2645 - Records of periodic spot-checks for gamma stereotactic radiosurgery units.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Records of periodic spot-checks for gamma stereotactic... MATERIAL Records § 35.2645 Records of periodic spot-checks for gamma stereotactic radiosurgery units. (a) A... and intercom systems, timer termination, treatment table retraction mechanism, and stereotactic frames...

  15. Evaluation of Different Score Index for Predicting Prognosis in Gamma Knife Radiosurgical Treatment for Brain Metastasis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Franzin, Alberto; Snider, Silvia; Picozzi, Piero

    2009-07-01

    Purpose: To assess the utility of the Radiation Therapy Oncology Group Recursive Partitioning Analysis (RPA) and Score Index for Radiosurgery (SIR) stratification systems in predicting survival in patients with brain metastasis treated with Gamma Knife radiosurgery (GKRS). Methods and Materials: A total of 185 patients were included in the study. Patients were stratified according to RPA and SIR classes. The RPA and SIR classes, age, Karnofsky Performance Status (KPS), and systemic disease were correlated with survival. Results: Five patients were lost to follow-up. Median survival in patients in RPA Class 1 (30 patients) was 17 months; in Class 2 (140more » patients), 10 months; and in Class 3 (10 patients), 3 months. Median survival in patients in SIR Class 1 (30 patients) was 3 months; in Class 2 (135 patients), 8 months; and in Class 3 (15 patients), 20 months. In univariate testing, age younger than 65 years (p = 0.0004), KPS higher than 70 (p = 0.0001), RPA class (p = 0.0078), SIR class (p = 0.0002), and control of the primary tumor (p = 0.02) were significantly associated with improved outcome. In multivariate analysis, KPS (p < 0.0001), SIR class (p = 0.0008), and RPA class (p = 0.03) had statistical value. Conclusions: This study supports the use of GKRS as a single-treatment modality in this selected group of patients. Stratification systems are useful in the estimation of patient eligibility for GKRS. A second-line treatment was necessary in 30% of patients to achieve distal or local brain control. This strategy is useful to control brain metastasis in long-surviving patients.« less

  16. Radiosurgery for metastatic disease at the craniocervical junction.

    PubMed

    Tuchman, Alexander; Yu, Cheng; Chang, Eric L; Kim, Paul E; Rusch, Mairead C; Apuzzo, Michael L J

    2014-12-01

    Metastatic disease of the craniovertebral junction (CVJ) can cause pain, cranial nerve deficits, occipitocervical instability, or brainstem/spinal cord compression if left untreated. Many patients with metastasis in this region have a high burden of systemic disease and short life expectancy, making them poor candidates for aggressive surgical resections and fusion procedures. Traditionally, symptom palliation and local disease control in these patients has been achieved through conventional radiation therapy. Stereotactic radiosurgery (SRS) has the advantage of precisely delivering radiation to a target in fewer fractions. To our knowledge, we report the results of the largest series of patients with CVJ metastasis treated with stereotactic radiosurgery. We performed a retrospective review of 9 consecutive patients with 10 tumors of the CVJ treated with SRS at the Keck Medical Center of the University of Southern California. Two tumors were treated with Gamma Knife, whereas the other 8 received CyberKnife. The median marginal dose was 20 Gy (16-24 Gy) over 1-5 fractions. Point maximal dose to the brainstem or spinal cord ranged between 8 and 18.9 Gy. Median survival was 4 months (1-51 months). Five of six patients presenting with pain had at least partial symptom resolution. No patient went on to require surgical decompression or fusion, and there were no complications directly related to SRS. In well-selected patients, SRS for metastatic lesions of the CVJ has a low risk for complications or treatment failure, while achieving a high rate of palliation of pain symptoms. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Vestibular schwannoma management: Part II. Failed radiosurgery and the role of delayed microsurgery.

    PubMed

    Pollock, Bruce E; Lunsford, L Dade; Kondziolka, Douglas; Sekula, Raymond; Subach, Brian R; Foote, Robert L; Flickinger, John C

    2013-12-01

    The indications, operative findings, and outcomes of vestibular schwannoma microsurgery are controversial when it is performed after stereotactic radiosurgery. To address these issues, the authors reviewed the experience at two academic medical centers. During a 10-year interval, 452 patients with unilateral vestibular schwannomas underwent gamma knife radiosurgery. Thirteen patients (2.9%) underwent delayed microsurgery at a median of 27 months (range 7–72 months) after they had undergone radiosurgery. Six of the 13 patients had undergone one or more microsurgical procedures before they underwent radiosurgery. The indications for surgery were tumor enlargement with stable symptoms in five patients, tumor enlargement with new or increased symptoms in five patients, and increased symptoms without evidence of tumor growth in three patients. Gross-total resection was achieved in seven patients and near-gross-total resection in four patients. The surgery was described as more difficult than that typically performed for schwannoma in eight patients, no different in four patients, and easier in one patient. At the last follow-up evaluation, three patients had normal or near-normal facial function, three patients had moderate facial dysfunction, and seven had facial palsies. Three patients were incapable of caring for themselves, and one patient died of progression of a malignant triton tumor. Failed radiosurgery in cases of vestibular schwannoma was rare. No clear relationship was demonstrated between the use of radiosurgery and the subsequent ease or difficulty of delayed microsurgery. Because some patients have temporary enlargement of their tumor after radiosurgery, the need for surgical resection after radiosurgery should be reviewed with the neurosurgeon who performed the radiosurgery and should be delayed until sustained tumor growth is confirmed. A subtotal tumor resection should be considered for patients who require surgical resection of their tumor after

  18. Gamma Knife Treatment of Growing Vestibular Schwannoma in Norway: A Prospective Study

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Varughese, Jobin Kotakkathu, E-mail: jobinv@gmail.com; Wentzel-Larsen, Tore; Centre for Child and Adolescent Mental Health, Eastern and Southern Norway, Oslo

    2012-10-01

    Purpose: Gamma Knife radiosurgery (GKRS) has been increasingly used in the treatment of vestibular schwannoma (VS). Very few studies relate tumor control and post-treatment growth rates to pretreatment growth rates. Methods and Materials: We prospectively included 45 consecutive VS patients who were initially treated conservatively and then received GKRS between 2000 and 2007 because of demonstrated tumor growth. Pretreatment and post-treatment tumor volumes were estimated. Patients underwent audiograms, reported their symptoms, and responded to the Short Form General Health Survey (SF-36) questionnaire on each visit. Results: Volume doubling times before and after treatment were 1.36 years (95% confidence intervals, 1.14-1.68)more » and -13.1 years (95% confidence intervals, -111.0 to -6.94), respectively. Tumor control, defined as a post-GKRS growth rate {<=}0, was achieved in 71.1% of patients, with highest odds for tumor control among older patients and those with larger tumors. The 5-year retreatment-free survival rate was 93.9% (95% confidence intervals, 76.5-98.5). None of the clinical endpoints investigated showed statistically significant changes after GKRS, but improvement was seen in a few SF-36 parameters. Conclusions: GKRS alters the natural course of the tumor by reducing growth. Mathematic models yield poorer tumor control rates than those found by clinical assessment. Symptoms were unaffected by treatment, but quality of life was improved.« less

  19. Technical note: A 3D-printed phantom for routine accuracy check of Gamma Knife Icon HDMM system.

    PubMed

    Wu, Chuan; Radevic, Marlyn B; Glass, Jennifer S; Skubic, Stan E

    2018-05-23

    To report a novel 3D-printed device ("SH phantom") that is designed for routine accuracy check of the Gamma Knife Icon High Definition Motion Management (HDMM) system. SH phantom was designed using tinkerCAD software and printed on a commercial 3D printer. We evaluated the SH phantom on our Gamma Knife Icon unit regarding its usability and accuracy for routine HDMM QA. Single-axis and multiple-axis measurements validated the SH phantom design and implementation. An HDMM QA accuracy of 0.22 mm or better along single axis was found using SH phantom. The SH phantom proved to be a quick and simple tool to use to perform the HDMM system QA. The SH phantom was tested successfully and adopted by us as part of monthly QA for the Gamma Knife Icon. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  20. Correction of measured Gamma-Knife output factors for angular dependence of diode detectors and PinPoint ionization chamber.

    PubMed

    Hršak, Hrvoje; Majer, Marija; Grego, Timor; Bibić, Juraj; Heinrich, Zdravko

    2014-12-01

    Dosimetry for Gamma-Knife requires detectors with high spatial resolution and minimal angular dependence of response. Angular dependence and end effect time for p-type silicon detectors (PTW Diode P and Diode E) and PTW PinPoint ionization chamber were measured with Gamma-Knife beams. Weighted angular dependence correction factors were calculated for each detector. The Gamma-Knife output factors were corrected for angular dependence and end effect time. For Gamma-Knife beams angle range of 84°-54°. Diode P shows considerable angular dependence of 9% and 8% for the 18 mm and 14, 8, 4 mm collimator, respectively. For Diode E this dependence is about 4% for all collimators. PinPoint ionization chamber shows angular dependence of less than 3% for 18, 14 and 8 mm helmet and 10% for 4 mm collimator due to volumetric averaging effect in a small photon beam. Corrected output factors for 14 mm helmet are in very good agreement (within ±0.3%) with published data and values recommended by vendor (Elekta AB, Stockholm, Sweden). For the 8 mm collimator diodes are still in good agreement with recommended values (within ±0.6%), while PinPoint gives 3% less value. For the 4 mm helmet Diodes P and E show over-response of 2.8% and 1.8%, respectively. For PinPoint chamber output factor of 4 mm collimator is 25% lower than Elekta value which is generally not consequence of angular dependence, but of volumetric averaging effect and lack of lateral electronic equilibrium. Diodes P and E represent good choice for Gamma-Knife dosimetry. Copyright © 2014 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  1. Fiducial migration following small peripheral lung tumor image-guided CyberKnife stereotactic radiosurgery

    NASA Astrophysics Data System (ADS)

    Strulik, Konrad L.; Cho, Min H.; Collins, Brian T.; Khan, Noureen; Banovac, Filip; Slack, Rebecca; Cleary, Kevin

    2008-03-01

    To track respiratory motion during CyberKnife stereotactic radiosurgery in the lung, several (three to five) cylindrical gold fiducials are implanted near the planned target volume (PTV). Since these fiducials remain in the human body after treatment, we hypothesize that tracking fiducial movement over time may correlate with the tumor response to treatment and pulmonary fibrosis, thereby serving as an indicator of treatment success. In this paper, we investigate fiducial migration in 24 patients through examination of computed tomography (CT) volume images at four time points: pre-treatment, three, six, and twelve month post-treatment. We developed a MATLAB based GUI environment to display the images, identify the fiducials, and compute our performance measure. After we semi-automatically segmented and detected fiducial locations in CT images of the same patient over time, we identified them according to their configuration and introduced a relative performance measure (ACD: average center distance) to detect their migration. We found that the migration tended to result in a movement towards the fiducial center of the radiated tissue area (indicating tumor regression) and may potentially be linked to the patient prognosis.

  2. Stereotactic radiosurgery of angiographically occult vascular malformations: Indications and preliminary experience

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kondziolka, D.; Lunsford, L.D.; Coffey, R.J.

    1990-12-01

    Stereotactic radiosurgery has been shown to treat successfully angiographically demonstrated arteriovenous malformations of the brain. Angiographic obliteration has represented cure and eliminated the risk of future hemorrhage. The role of radiosurgery in the treatment of angiographically occult vascular malformations (AOVMs) has been less well defined. In the initial 32 months of operation of the 201-source cobalt-60 gamma knife at the University of Pittsburgh, 24 patients meeting strict criteria for high-risk AOVMs were treated. Radiosurgery was used conservatively; each patient had sustained two or more hemorrhages and had a magnetic resonance imaging-defined AOVM located in a region of the brain wheremore » microsurgical removal was judged to pose an excessive risk. Venous angiomas were excluded by performance of high-resolution subtraction angiography in each patient. Fifteen malformations were in the medulla, pons, and/or mesencephalon, and 5 were located in the thalamus or basal ganglia. Follow-up ranged from 4 to 24 months. Nineteen patients either improved or remained clinically stable and did not hemorrhage again during the follow-up interval. One patient suffered another hemorrhage 7 months after radiosurgery. Five patients experienced temporary worsening of pre-existing neurological deficits that suggested delayed radiation injury. Magnetic resonance imaging demonstrated signal changes and edema surrounding the radiosurgical target. Dose-volume guidelines for avoiding complications were constructed. Our initial experience indicates that stereotactic radiosurgery can be performed safely in patients with small, well-circumscribed AOVMs located in deep, critical, or relatively inaccessible cerebral locations.« less

  3. Safety and efficacy of Gamma Knife radiosurgery in hypothalamic hamartomas with severe epilepsies: A prospective trial in 48 patients and review of the literature.

    PubMed

    Régis, Jean; Lagmari, Medhi; Carron, Romain; Hayashi, Motohiro; McGonigal, Aileen; Daquin, Géraldine; Villeneuve, Nathalie; Laguitton, Virginie; Bartolomei, Fabrice; Chauvel, Patrick

    2017-06-01

    Epilepsies associated with hypothalamic hamartomas (HHs) are frequently drug resistant with severe psychiatric and cognitive comorbidities. We performed a prospective trial to evaluate the safety and efficacy of Gamma Knife radiosurgery (GKS). Between October 1999 and October 2007, a total of 57 patients were investigated, included and treated by GKS in Timone University Hospital. Preoperative workup and 3-year postoperative evaluation consisted of seizure diary, neuropsychological, psychiatric, endocrinologic, visual field, and visual acuity examinations. Follow-up of >3 years was available for 48 patients. Topologic type was type I in 11 patients, type II in 15, type III in 17, type IV in one, type V in one, type VI in one, and mixed type in 2. The median marginal dose was 17 Gy (min 14 and max 25 Gy). The median target volume was 398 mm 3 (28-1,600 mm 3 ). Due to partial results, 28 patients (58.3%) required a second treatment. The median follow-up was 71 months (36-153 months). At last follow-up, the rate of Engel class I outcome was 39.6%, Engel class II was 29.2% (I+II 68.8%), and Engel class III was 20%. Global psychiatric comorbidity was considered cured in 28%, improved in 56%, stable in 8%, and continued to worsen in 8%. No permanent neurologic side effect was reported (in particular, no memory deficit). Nondisabling transient poikilothermia was observed in three patients (6.2%). A transient increase of seizure frequency was reported in 8 patients (16.6%) with a median duration of 30 days (9-90 days). Microsurgery was proposed because of insufficient efficacy of GKS in seven patients (14.5%) with a postoperative Engel class I-II in 28.6%. This prospective trial demonstrates very good long-term safety and efficacy of GKS for 2 patients. Beyond seizure reduction, the improvement of psychiatric and cognitive comorbidities along with better school performance and social functioning, being better socially integrated, having friends having a social life

  4. Where to locate the isocenter? The treatment strategy for repeat trigeminal neuralgia radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Zhang Pengpeng; Brisman, Ronald; Choi, Julie

    2005-05-01

    Purpose: The purpose of this study is to investigate how the spatial relationship between the isocenters of the first and second radiosurgeries affects the overall outcome. Methods and Materials: We performed a retrospective study on 40 patients who had repeat gamma knife radiosurgery for trigeminal neuralgia. Only one 4-mm isocenter was applied in both first and second radiosurgeries, with a maximum radiation dose of 75 Gy and 40 Gy, respectively. The MR scan of the first radiosurgery was registered to that of the second radiosurgery by a landmark-based registration algorithm. The spatial relationship between the isocenter of the first andmore » the second radiosurgeries was thus determined. The investigating parameters were the distance between the isocenters of the two separate radiosurgeries and isocenter proximity to the brainstem. The outcome end points were pain relief and dysesthesias. The median follow-up for the repeat radiosurgery was 28 months (range, 6-51 months). Results: Pain relief was complete in 11 patients, nearly complete ({>=}90%) in 7 patients, partial ({>=}50%) in 8 patients, and minimal (<50%) or none in another 14 patients. The mean distance between the two isocenters was 2.86 mm in the complete or nearly complete pain relief group vs. 1.93 mm in the others. Farther distance between isocenters was associated with a trend toward better pain relief (p 0.057). The proximity of the second isocenter to the brainstem did not affect pain relief, and neither did placing the second isocenter proximal or distal to the brainstem compared with the first one. Three patients developed moderate dysesthesias (score of 4 on a 0-10 scale), and 2 other patients developed more significant dysesthesias (score of 7) after the second radiosurgery. Dysesthesias related neither to distance between isocenters nor to which isocenter was closer to the brainstem. Conclusions: Image registration between MR scans of the first and second radiosurgeries helps target

  5. A treatment planning comparison between a novel rotating gamma system and robotic linear accelerator based intracranial stereotactic radiosurgery/radiotherapy

    NASA Astrophysics Data System (ADS)

    Fareed, Muhammad M.; Eldib, Ahmed; Weiss, Stephanie E.; Hayes, Shelly B.; Li, Jinsheng; C-M Ma, Charlie

    2018-02-01

    To compare the dosimetric parameters of a novel rotating gamma ray system (RGS) with well-established CyberKnife system (CK) for treating malignant brain lesions. RGS has a treatment head of 16 cobalt-60 sources focused to the isocenter, which can rotate 360° on the ring gantry and swing 35° in the superior direction. We compared several dosimetric parameters in 10 patients undergoing brain stereotactic radiosurgery including plan normalization, number of beams and nodes for CK and shots for RGS, collimators used, estimated treatment time, D 2 cm and conformity index (CI) among two modalities. The median plan normalization for RGS was 56.7% versus 68.5% (p  =  0.002) for CK plans. The median number of shots from RGS was 7.5 whereas the median number of beams and nodes for CK was 79.5 and 46. The median collimator’s diameter used was 3.5 mm for RGS as compared to 5 mm for CK (p  =  0.26). Mean D 2 cm was 5.57 Gy for CyberKnife whereas it was 3.11 Gy for RGS (p  =  0.99). For RGS plans, the median CI was 1.4 compared to 1.3 for the CK treatment plans (p  =  0.98). The average minimum and maximum doses to optic chiasm were 21 and 93 cGy for RGS as compared to 32 and 209 cGy for CK whereas these were 0.5 and 364 cGy by RGS and 18 and 399 cGy by CK to brainstem. The mean V12 Gy for brain predicting for radionecrosis with RGS was 3.75 cm3 as compared to 4.09 cm3 with the CK (p  =  0.41). The dosimetric parameters of a novel RGS with a ring type gantry are comparable with CyberKnife, allowing its use for intracranial lesions and is worth exploring in a clinical setting.

  6. Stereotactic Radiosurgery - Gamma Knife

    MedlinePlus

    ... nerve that connects the ear to the brain ( acoustic neuroma ) Pituitary tumors Tumors that are not cancer ( ... and the A.D.A.M. Editorial team. Acoustic Neuroma Read more Brain Tumors Read more Radiation ...

  7. Radiosurgery with photons or protons for benign and malignant tumours of the skull base: a review.

    PubMed

    Amichetti, Maurizio; Amelio, Dante; Minniti, Giuseppe

    2012-12-14

    Stereotactic radiosurgery (SRS) is an important treatment option for intracranial lesions. Many studies have shown the effectiveness of photon-SRS for the treatment of skull base (SB) tumours; however, limited data are available for proton-SRS.Several photon-SRS techniques, including Gamma Knife, modified linear accelerators (Linac) and CyberKnife, have been developed and several studies have compared treatment plan characteristics between protons and photons.The principles of classical radiobiology are similar for protons and photons even though they differ in terms of physical properties and interaction with matter resulting in different dose distributions.Protons have special characteristics that allow normal tissues to be spared better than with the use of photons, although their potential clinical superiority remains to be demonstrated.A critical analysis of the fundamental radiobiological principles, dosimetric characteristics, clinical results, and toxicity of proton- and photon-SRS for SB tumours is provided and discussed with an attempt of defining the advantages and limits of each radiosurgical technique.

  8. Radiosurgery with photons or protons for benign and malignant tumours of the skull base: a review

    PubMed Central

    2012-01-01

    Stereotactic radiosurgery (SRS) is an important treatment option for intracranial lesions. Many studies have shown the effectiveness of photon-SRS for the treatment of skull base (SB) tumours; however, limited data are available for proton-SRS. Several photon-SRS techniques, including Gamma Knife, modified linear accelerators (Linac) and CyberKnife, have been developed and several studies have compared treatment plan characteristics between protons and photons. The principles of classical radiobiology are similar for protons and photons even though they differ in terms of physical properties and interaction with matter resulting in different dose distributions. Protons have special characteristics that allow normal tissues to be spared better than with the use of photons, although their potential clinical superiority remains to be demonstrated. A critical analysis of the fundamental radiobiological principles, dosimetric characteristics, clinical results, and toxicity of proton- and photon-SRS for SB tumours is provided and discussed with an attempt of defining the advantages and limits of each radiosurgical technique. PMID:23241206

  9. Long-Term Results for Trigeminal Schwannomas Treated With Gamma Knife Surgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hasegawa, Toshinori, E-mail: h-toshi@komakihp.gr.jp; Kato, Takenori; Iizuka, Hiroshi

    Purpose: Surgical resection is considered the desirable curative treatment for trigeminal schwannomas. However, complete resection without any complications remains challenging. During the last several decades, stereotactic radiosurgery (SRS) has emerged as a minimally invasive treatment modality. Information regarding long-term outcomes of SRS for patients harboring trigeminal schwannomas is limited because of the rarity of this tumor. The aim of this study was to evaluate long-term tumor control and functional outcomes in patients harboring trigeminal schwannomas treated with SRS, specifically with gamma knife surgery (GKS). Methods and Materials: Fifty-three patients harboring trigeminal schwannomas treated with GKS were evaluated. Of these, 2more » patients (4%) had partial irradiation of the tumor, and 34 patients (64%) underwent GKS as the initial treatment. The median tumor volume was 6.0 cm{sup 3}. The median maximum and marginal doses were 28 Gy and 14 Gy, respectively. Results: The median follow-up period was 98 months. On the last follow-up image, 7 patients (13%) had tumor enlargement, including the 2 patients who had partial treatment. Excluding the 2 patients who had partial treatment, the actuarial 5- and 10-year progression-free survival (PFS) rates were 90% and 82%, respectively. Patients with tumors compressing the brainstem with deviation of the fourth ventricle had significantly lower PFS rates. If those patients with tumors compressing the brainstem with deviation of the fourth ventricle are excluded, the actuarial 5- and 10-year PFS rates increased to 95% and 90%, respectively. Ten percent of patients had worsened facial numbness or pain in spite of no tumor progression, indicating adverse radiation effect. Conclusions: GKS can be an acceptable alternative to surgical resection in patients with trigeminal schwannomas. However, large tumors that compress the brainstem with deviation of the fourth ventricle should be surgically removed first

  10. Brain metastases in women with epithelial ovarian cancer: multimodal treatment including surgery or gamma-knife radiation is associated with prolonged survival.

    PubMed

    Niu, Xiaoyu; Rajanbabu, Anupama; Delisle, Megan; Peng, Feng; Vijaykumar, Dehannathuparambil K; Pavithran, Keechilattu; Feng, Yukuan; Lau, Susie; Gotlieb, Walter H; Press, Joshua Z

    2013-09-01

    To explore the impact of treatment modality on survival in patients with brain metastases from epithelial ovarian cancer. We conducted a retrospective review of cases of ovarian cancer with brain metastases treated at institutions in three countries (Canada, China, and India) and conducted a search for studies regarding brain metastases in ovarian cancer reporting survival related to treatment modality. Survival was analyzed according to treatment regimens involving (1) some form of surgical excision or gamma-knife radiation with or without other modalities, (2) other modalities without surgery or gamma-knife radiation, or (3) palliation only. Twelve patients (mean age 56 years) with detailed treatment/outcome data were included; five were from China, four from Canada, and three from India. Median time from diagnosis of ovarian cancer to brain metastasis was 19 months (range 10 to 37 months), and overall median survival time from diagnosis of ovarian cancer was 38 months (13 to 82 months). Median survival time from diagnosis of brain metastasis was 17 months (1 to 45 months). Among patients who had multimodal treatment including gamma-knife radiotherapy or surgical excision, the median survival time after the identification of brain metastasis was 25.6 months, compared with 6.0 months in patients whose treatment did not include this type of focused localized modality (P = 0.006). Analysis of 20 studies also indicated that use of gamma-knife radiotherapy and excisional surgery in multi-modal treatment resulted in improved median survival interval (25 months vs. 6.0 months, P < 0.001). In the subset of patients with brain metastases from ovarian cancer, prolonged survival may result from use of multidisciplinary therapy, particularly if metastases are amenable to localized treatments such as gamma-knife radiotherapy and surgical excision.

  11. SU-E-T-404: Evaluation of the Effect of Spine Hardware for CyberKnife Spinal Stereotactic Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yuan, J; Zhang, Y; Zheng, Y

    2015-06-15

    Purpose: Spine hardware made of high-Z materials such as titanium has the potential to affect the dose distribution around the metal rods in CyberKnife spinal stereotactic radiosurgery (SRS) treatments. The purpose of this work was to evaluate the magnitude of such effect retrospectively for clinical CyberKnife plans. Methods: The dose calculation was performed within the MultiPlan treatment planning system using the ray tracing (RT) and Monte Carlo (MC) method. A custom density model was created by extending the CT-to-Density table to titanium density of 4.5 g/cm3 with the CT number of 4095. To understand the dose perturbation caused by themore » titanium rod, a simple beam setup (7.5 mm IRIS collimator) was used to irradiate a mimic rod (5 mm) with overridden high density. Five patient spinal SRS cases were found chronologically from 2010 to 2015 in our institution. For each case, the hardware was contoured manually. The original plan was re-calculated using both RT and MC methods with and without rod density override without changing clinical beam parameters. Results: The simple beam irradiation shows that there is 10% dose increase at the interface because of electron backscattering and 7% decrease behind the rod because of photon attenuation. For actual clinical plans, the iso-dose lines and DVHs are almost identical (<2%) for calculations with and without density override for both RT and MC methods. However, there is a difference of more than 10% for D90 between RT and MC method. Conclusion: Although the dose perturbation around the metal rods can be as large as 10% for a single beam irradiation, for clinical treatments with complex beam composition the effect of spinal hardware to the PTV and spinal dose is minimal. As such, the MC dose algorithm without rod density override for CyberKnife spinal SRS is acceptable.« less

  12. [Alterations of glial fibrillary acidic protein in rat brain after gamma knife irradiation].

    PubMed

    Ma, Z M; Jiang, B; Ma, J R

    2001-08-28

    To study glial fibrillary acidic protein (GFAP) immunoreactivity in different time and water content of the rat brain treated with gamma knife radiotherapy and to understand the alteration course of the brain lesion after a single high dose radiosurgical treatment. In the brains of the normal rats were irradiated by gamma knife with 160 Gy-high dose. The irradiated rats were then killed on the 1st day, 7th day, 14th day, and 28th day after radiotherapy, respectively. The positive cells of GFAP in brain tissue were detected by immunostaining; the water content of the brain tissue was measured by microgravimetry. The histological study of the irradiated brain tissue was performed with H.E. and examined under light microscope. The numbers of GFAP-positive astrocytes began to increase on the 1st day after gamma knife irradiation. It was enlarged markedly in the number and size of GFAP-stained astrocytes over the irradiated areas. Up to the 28th day, circumscribed necrosis foci (4 mm in diameter) was seen in the central area of the target. In the brain tissue around the necrosis, GFAP-positive astrocytes significantly increased (P < 0.01, compared with the control group). The swelling of cells in irradiated region was observed on the 1st day; after irradiation endothelial cells degenerated and red blood cells escaped from blood vessel on the 7th day; leakage of Evans blue dye was observed in the target region on the 14th day. There was a significant decrease of specific gravity in the irradiated brain tissue the 14th and 28th day after irradiation. The results suggest that GFAP can be used as a marker for the radiation-induced brain injury. The brain edema and disruption of brain-blood barrier can be occurred during the acute stage after irradiation.

  13. Clinical outcome of fiducial-less CyberKnife radiosurgery for stage I non-small cell lung cancer

    PubMed Central

    Jung, In-Hye; Jung, Jinhong; Cho, Byungchul; Kwak, Jungwon; Je, Hyoung Uk; Choi, Wonsik; Jung, Nuri Hyun; Kim, Su Ssan; Choi, Eun Kyung

    2015-01-01

    Purpose To evaluate the treatment results in early stage non-small cell lung cancer patients who have undergone fiducial-less CyberKnife radiosurgery (CKRS). Materials and Methods From June 2011 to November 2013, 58 patients underwent CKRS at Asan Medical Center for stage I lung cancer. After excluding 14 patients, we retrospectively reviewed the records of the remaining 44 patients. All analyses were performed using SPSS ver. 21. Results The median age at diagnosis was 75 years. Most patients had inoperable primary lung cancer with a poor pulmonary function test with comorbidity or old age. The clinical stage was IA in 30 patients (68.2%), IB in 14 (31.8%). The mean tumor size was 2.6 cm (range, 1.2 to 4.8 cm), and the tumor was smaller than 2 cm in 12 patients (27.3%). The radiation dose given was 48-60 Gy in 3-4 fractions. In a median follow-up of 23.1 months, local recurrence occurred in three patients (2-year local recurrence-free survival rate, 90.4%) and distant metastasis occurred in 13 patients. All patients tolerated the radiosurgery well, only two patients developing grade 3 dyspnea. The most common complications were radiation-induced fibrosis and pneumonitis. Eight patients died due to cancer progression. Conclusion The results showed that fiducial-less CKRS shows comparable local tumor control and survival rates to those of LINAC-based SABR or CKRS with a fiducial marker. Thus, fiducial-less CKRS using Xsight lung tracking system can be effectively and safely performed for patients with medically inoperable stage I non-small cell lung cancer without any risk of procedure-related complication. PMID:26157678

  14. A randomised trial to compare cognitive outcome after gamma knife radiosurgery versus whole brain radiation therapy in patients with multiple brain metastases: research protocol CAR-study B.

    PubMed

    Schimmel, Wietske C M; Verhaak, Eline; Hanssens, Patrick E J; Gehring, Karin; Sitskoorn, Margriet M

    2018-02-21

    Gamma Knife radiosurgery (GKRS) is increasingly applied in patients with multiple brain metastases and is expected to have less adverse effects in cognitive functioning than whole brain radiation therapy (WBRT). Effective treatment with the least negative cognitive side effects is increasingly becoming important, as more patients with brain metastases live longer due to more and better systemic treatment options. There are no published randomized trials yet directly comparing GKRS to WBRT in patients with multiple brain metastases that include objective neuropsychological testing. CAR-Study B is a prospective randomised trial comparing cognitive outcome after GKRS or WBRT in adult patients with 11-20 newly diagnosed brain metastases on a contrast-enhanced MRI-scan, KPS ≥70 and life expectancy of at least 3 months. Randomisation by the method of minimization, is stratified by the cumulative tumour volume in the brain, systemic treatment, KPS, histology, baseline cognitive functioning and age. The primary endpoint is the between-group difference in the percentage of patients with significant memory decline at 3 months. Secondary endpoints include overall survival, local control, development of new brain metastases, cognitive functioning over time, quality of life, depression, anxiety and fatigue. Cognitive functioning is assessed by a standardised neuropsychological test battery. Assessments (cognitive testing, questionnaires and MRI-scans) are scheduled at baseline and at 3, 6, 9, 12 and 15 months after treatment. Knowledge gained from this trial may be used to inform individual patients with BM more precisely about the cognitive effects they can expect from treatment, and to assist both doctors and patients in making (shared) individual treatment decisions. This trial is currently recruiting. Target accrual: 23 patients at 3-months follow-up in both groups. The Netherlands Trials Register number NTR5463. ClinicalTrials.gov registration number NCT02953717

  15. Immune checkpoint inhibitors and radiosurgery for newly diagnosed melanoma brain metastases.

    PubMed

    Robin, Tyler P; Breeze, Robert E; Smith, Derek E; Rusthoven, Chad G; Lewis, Karl D; Gonzalez, Rene; Brill, Amanda; Saiki, Robin; Stuhr, Kelly; Gaspar, Laurie E; Karam, Sana D; Raben, David; Kavanagh, Brian D; Nath, Sameer K; Liu, Arthur K

    2018-06-16

    Brain metastases are common in metastatic melanoma and radiosurgery is often utilized for local control. Immune checkpoint inhibitors (CPIs) play a central role in contemporary melanoma management; however, there is limited data exploring outcomes and potential toxicities for patients treated with CPIs and radiosurgery. We retrospectively identified all consecutive cases of newly diagnosed melanoma brain metastases (MBM) treated with Gamma Knife radiosurgery at a single institution between 2012 and 2017, and included only patients that initiated CPIs within 8 weeks before or after radiosurgery. Thirty-eight patients were included with a median follow-up of 31.6 months. Two-year local control was 92%. Median time to out-of-field CNS and extra-CNS progression were 8.4 and 7.9 months, respectively. Median progression-free survival (PFS) was 3.4 months and median overall survival (OS) was not reached (NR). Twenty-five patients (66%) received anti-CTLA4 and 13 patients (34%) received anti-PD-1+/-anti-CTLA4. Compared with anti-CTLA4, patients that received anti-PD-1+/-anti-CTLA4 had significant improvements in time to out-of-field CNS progression (p = 0.049), extra-CNS progression (p = 0.015), and PFS (p = 0.043), with median time to out-of-field CNS progression of NR vs. 3.1 months, median time to extra-CNS progression of NR vs. 4.4 months, and median PFS of 20.3 vs. 2.4 months. Six patients (16%) developed grade ≥ 2 CNS toxicities (grade 2: 3, grade 3: 3, grade 4/5: 0). Excellent outcomes were observed in patients that initiated CPIs within 8 weeks of undergoing radiosurgery for newly diagnosed MBM. There appears to be an advantage to anti-PD-1 or combination therapy compared to anti-CTLA4.

  16. Rare case of malignant craniopharyngioma reactive to adjunctive stereotactic radiotherapy and chemotherapy; Case report and review.

    PubMed

    Nomura, Shunsunke; Aihara, Yasuo; Amano, Kosaku; Eguchi, Seiichiro; Chiba, Kentaro; Komori, Takashi; Kawamata, Takakazu

    2018-06-19

    Malignant craniopharyngioma or anaplastic craniopharyngioma was first reported in 1987 by Akachi. It has a malignant clinical and histological feature; remarkably rapid progression, atypical pathology like squamous cell carcinoma and poor prognosis. To date seventeen cases of malignant craniopharyngioma have been reported and of these cases, most were of secondary malignant tumor in nature. With respect to traditional benign craniopharyngioma, adjunctive treatment after gross total removal is not necessary, but in the case of malignant types of the tumor, adjunctive treatment is important. This paper presents the first case of malignant craniopharyngioma reactive to adjunctive Gamma knife stereotactic radiosurgery and chemotherapy. Malignant craniopharyngioma is very rare, and we report Gamma knife stereotactic radiosurgery and chemotherapy (Carboplatine and etoposide chemotherapy), as well as Temozolomide chemotherapy were effective and could control progression of the tumor temporarily. Since adjunctive Gamma knife stereotactic radiosurgery and chemotherapy of malignant craniopharyngioma cases affects follow-up strategies, we propose supporting the need to a revision to the WHO classification regarding malignancy evaluation of craniopharyngioma. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Mid-term prognosis of non-functioning pituitary adenomas with high proliferative potential: really an aggressive variant?

    PubMed

    Ogawa, Yoshikazu; Jokura, Hidefumi; Niizuma, Kuniyasu; Tominaga, Teiji

    2018-05-01

    Pituitary adenomas with high proliferation rate and rapid growth are well known, but the clinical characteristics, prognosis, and treatment algorithm remain unclear. The clinical characteristics and mid-term prognosis of patients with non-functioning pituitary adenomas with high proliferative potential were retrospectively investigated. This study identified 53 patients with Ki-67 labeling index of > 3% among 845 patients with non-functioning pituitary adenoma (6.3%) initially treated by surgery. Prophylactic treatment was not applied for patients with residual tumor, but salvage treatment was performed if tumor progression was identified within the follow-up period. Twenty-two patients remained progression-free, whereas 31 patients suffered tumor progression. Comparison of gross total removal (n = 22) and non-total removal (n = 31) groups showed significantly longer progression-free period in the former group (P < 0.001). As salvage treatment gamma knife radiosurgery was applied for 11 patients resulting in 10 patients remaining progression-free and regrowth in 1 patient. Fractionated irradiation was applied for 10 patients, resulting in 2 patients remaining progression-free, deaths in 5 patients including 3 of transformation to pituitary carcinoma, dementia in 1 patient caused by frontal lobe dysfunction, and progression in 2 patients requiring additional surgery and gamma knife radiosurgery. Temozolomide was administered in 2 patients, resulting in deaths in both patients including 1 transformation to pituitary carcinoma. Total removal and gamma knife radiosurgery can result in good outcome. However, the prognosis is extremely poor for patients inadequate for gamma knife radiosurgery. Development of new salvage treatments is essential.

  18. The safety and efficacy of gamma knife surgery in management of glomus jugulare tumor

    PubMed Central

    2010-01-01

    Background Glomus jugulare is a slowly growing, locally destructive tumor located in the skull base with difficult surgical access. The operative approach is, complicated by the fact that lesions may be both intra and extradural with engulfment of critical neurovascular structures. The tumor is frequently highly vascular, thus tumor resection entails a great deal of morbidity and not infrequent mortality. At timeslarge residual tumors are left behind. To decrease the morbidity associated with surgical resection of glomus jugulare, gamma knife surgery (GKS) was performed as an alternative in 13 patients to evaluate its safety and efficacy. Methods A retrospective review of 13 residual or unresectable glomus jagulare treated with GKS between 2004 and 2008.. Of these, 11 patients underwent GKS as the primary management and one case each was treated for postoperative residual disease and postembolization. The radiosurgical dose to the tumor margin ranged between 12-15 Gy. Results Post- gamma knife surgery and during the follow-up period twelve patients demonstrated neurological stability while clinical improvement was achieved in 5 patients. One case developed transient partial 7th nerve palsy that responded to medical treatment. In all patients radiographic MRI follow-up was obtained, the tumor size decreased in two cases and remained stable (local tumor control) in eleven patients. Conclusions Gamma knife surgery provids tumor control with a lowering of risk of developing a new cranial nerve injury in early follow-up period. This procedure can be safely used as a primary management tool in patients with glomus jugulare tumors, or in patients with recurrent tumors in this location. If long-term results with GKS are equally effective it will emerge as a good alternative to surgical resection. PMID:20819207

  19. Clinical efficacy of gamma knife and surgery treatment of mesial temporal lobe epilepsy and their effects on EF-Tumt and EF-Tsmt expression.

    PubMed

    Wang, X-Q; Zhang, X-D; Han, Y-M; Shi, X-F; Lan, Z-B; Men, X-X; Pan, Y-W

    2017-04-01

    To study the clinical efficacy of gamma knife and surgery treatment of mesial temporal lobe epilepsy (MTLE) and their effects on EF-Tumt and EF-Tsmt expression. The data of 78 cases of MTLE patients treated in our hospital from April 2011 to March 2013 were retrospectively analyzed. The patients were divided into two groups according to the treatment methods: the surgery group (including 41 cases) and the gamma knife group (including 37 cases). The clinical efficacy, the occurrence and recurrence of complications were evaluated, respectively; meanwhile, the expression of the EF-Tumt protein and EF-Tsmt protein in brain tissue were analyzed. The difference between the efficacy rate of the two groups showed no statistical significance (χ2=0.960, p>0.05). The complication rate of the gamma knife group was significantly lower than that of the control group (χ2=6.430, p<0.05). The recurrence rate of the patients in the gamma knife group was significantly lower than that of the patients in the surgery group (p>0.05). Within the two groups, the positive expression granum of EF-Tsmt protein and EF-Tumt protein of the two groups after treatment were significantly lower than that before treatment (p<0.05). After treatment, the positive expression granum of EF-Tsmt protein of the patients in the gamma knife group was obviously more than that of the patients in the surgery group (p<0.05). The difference between the positive expression granum of EF-Tumt protein of the two groups showed no statistical significance (p>0.05). Before and after treatment within the group, the positive cell of EF-Tsmt protein and EF-Tumt protein of the two groups of patients after treatment were significantly lower than that before treatment (p<0.05). After treatment, the difference between the EF-Tsmt protein positive cell and the EF-Tumt protein positive cell of the two groups of patients showed no statistical significance (p>0.05). Both surgery and gamma knife could treat MTLE effectively, and

  20. MO-F-CAMPUS-T-03: Continuous Dose Delivery with Gamma Knife Perfexion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ghobadi,; Li, W; Chung, C

    2015-06-15

    Purpose: We propose continuous dose delivery techniques for stereotactic treatments delivered by Gamma Knife Perfexion using inverse treatment planning system that can be applied to various tumour sites in the brain. We test the accuracy of the plans on Perfexion’s planning system (GammaPlan) to ensure the obtained plans are viable. This approach introduces continuous dose delivery for Perefxion, as opposed to the currently employed step-and-shoot approaches, for different tumour sites. Additionally, this is the first realization of automated inverse planning on GammaPlan. Methods: The inverse planning approach is divided into two steps of identifying a quality path inside the target,more » and finding the best collimator composition for the path. To find a path, we select strategic regions inside the target volume and find a path that visits each region exactly once. This path is then passed to a mathematical model which finds the best combination of collimators and their durations. The mathematical model minimizes the dose spillage to the surrounding tissues while ensuring the prescribed dose is delivered to the target(s). Organs-at-risk and their corresponding allowable doses can also be added to the model to protect adjacent organs. Results: We test this approach on various tumour sizes and sites. The quality of the obtained treatment plans are comparable or better than forward plans and inverse plans that use step- and-shoot technique. The conformity indices in the obtained continuous dose delivery plans are similar to those of forward plans while the beam-on time is improved on average (see Table 1 in supporting document). Conclusion: We employ inverse planning for continuous dose delivery in Perfexion for brain tumours. The quality of the obtained plans is similar to forward and inverse plans that use conventional step-and-shoot technique. We tested the inverse plans on GammaPlan to verify clinical relevance. This research was partially supported by

  1. Tolerance of cranial nerves of the cavernous sinus to radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Tishler, R.B.; Loeffler, J.S.; Alexander, E. III

    1993-09-20

    Stereotactic radiosurgery is becoming a more accepted treatment option for benign, deep seated intracranial lesions. However, little is known about the effects of large single fractions of radiation on cranial nerves. This study was undertaken to assess the effect of radiosurgery on the cranial nerves of the cavernous sinus. The authors examined the tolerance of cranial nerves (II-VI) following radiosurgery for 62 patients (42/62 with meningiomas) treated for lesions within or near the cavernous sinus. Twenty-nine patients were treated with a modified 6 MV linear accelerator (Joint Center for Radiation Therapy) and 33 were treated with the Gamma Knife (Universitymore » of Pittsburgh). Three-dimensional treatment plans were retrospectively reviewed and maximum doses were calculated for the cavernous sinus and the optic nerve and chiasm. Median follow-up was 19 months (range 3-49). New cranial neuropathies developed in 12 patients from 3-41 months following radiosurgery. Four of these complications involved injury to the optic system and 8 (3/8 transient) were the result of injury to the sensory or motor nerves of the cavernous sinus. There was no clear relationship between the maximum dose to the cavernous sinus and the development of complications for cranial nerves III-VI over the dose range used (1000-4000 cGy). For the optic apparatus, there was a significantly increased incidence of complications with dose. Four of 17 patients (24%) receiving greater than 800 cGy to any part of the optic apparatus developed visual complications compared with 0/35 who received less than 800 cGy (p = 0.009). Radiosurgery using tumor-controlling doses of up to 4000 cGy appears to be a relatively safe technique in treating lesions within or near the sensory and motor nerves (III-VI) of the cavernous sinus. The dose to the optic apparatus should be limited to under 800 cGy. 21 refs., 4 tabs.« less

  2. Brain metastases in cancer patients attending a Gamma Knife Center: A study from a single institute in Iran

    PubMed Central

    Azimi, Parisa; Shahzadi, Sohrab; Bitaraf, Mohammad Ali; Azar, Maziar; Alikhani, Mazdak; Zali, Alireza; Sadeghi, Sohrab; Montazeri, Ali

    2017-01-01

    Background: This study was aimed to explore data on brain metastases in cancer patients attending the Iranian Gamma Knife Center. Meterials and Methods: This was a retrospective study. In all 5216 case records of patients who referred to the Iranian Gamma Knife Center for treatment of brain tumors during year 2003-2011 were reviewed. Data were explored to identify patients who developed brain metastases due to cancer and assessed the information as applied to cancer patients including survival analysis. Results: Two hundred and twenty patients were identified as having brain metastases due to cancer. The mean age of patients was 54.0 (standard deviation [SD] =12.7) years. Patients were followed for an average of 7 months after treatment with gamma-knife. The median survival time for different the Graded Prognostic Assessment (GPA) was: GPA: 0-1, 4.0 ± 0.4 months; GPA: 1.5-2.5, 6.0 ± 0.7 months; GPA: 3, 9.0 ± 0.9 months; and GPA: 3.5-4.0, 12.0 ± 1.8 months and the overall median survival was 7.0 (SD = 0.6) months. Conclusion: The findings suggest that many cancer patients in Iran might develop brain metastasis. Although, this is not a very high incidence compared with the existing statistics from other countries, there is an urgent need to explore the issue further. PMID:28761536

  3. Brain metastases in cancer patients attending a Gamma Knife Center: A study from a single institute in Iran.

    PubMed

    Azimi, Parisa; Shahzadi, Sohrab; Bitaraf, Mohammad Ali; Azar, Maziar; Alikhani, Mazdak; Zali, Alireza; Sadeghi, Sohrab; Montazeri, Ali

    2017-01-01

    This study was aimed to explore data on brain metastases in cancer patients attending the Iranian Gamma Knife Center. This was a retrospective study. In all 5216 case records of patients who referred to the Iranian Gamma Knife Center for treatment of brain tumors during year 2003-2011 were reviewed. Data were explored to identify patients who developed brain metastases due to cancer and assessed the information as applied to cancer patients including survival analysis. Two hundred and twenty patients were identified as having brain metastases due to cancer. The mean age of patients was 54.0 (standard deviation [SD] =12.7) years. Patients were followed for an average of 7 months after treatment with gamma-knife. The median survival time for different the Graded Prognostic Assessment (GPA) was: GPA: 0-1, 4.0 ± 0.4 months; GPA: 1.5-2.5, 6.0 ± 0.7 months; GPA: 3, 9.0 ± 0.9 months; and GPA: 3.5-4.0, 12.0 ± 1.8 months and the overall median survival was 7.0 (SD = 0.6) months. The findings suggest that many cancer patients in Iran might develop brain metastasis. Although, this is not a very high incidence compared with the existing statistics from other countries, there is an urgent need to explore the issue further.

  4. The journey from proton to gamma knife.

    PubMed

    Ganz, Jeremy C

    2014-01-01

    It was generally accepted by the early 1960s that proton beam radiosurgery was too complex and impractical. The need was seen for a new machine. The beam design had to be as good as a proton beam. It was also decided that a static design was preferable even if the evolution of that notion is no longer clear. Complex collimators were designed that using sources of cobalt-60 could produce beams with characteristics adequately close to those of proton beams. The geometry of the machine was determined including the distance of the sources from the patient the optimal distance between the sources. The first gamma unit was built with private money with no contribution from the Swedish state, which nonetheless required detailed design information in order to ensure radiation safety. This original machine was built with rectangular collimators to produce lesions for thalamotomy for functional work. However, with the introduction of dopamine analogs, this indication virtually disappeared overnight.

  5. Successful use of Gamma Knife surgery in a distal lenticulostriate artery aneurysm intervention.

    PubMed

    Lan, ZhiGang; Li, Jin; You, Chao; Chen, Jing

    2012-02-01

    We report a case of a 21-year-old woman who underwent radiosurgical treatment of a distal lenticulostriate artery (LSA) aneurysm. Twenty-two months after treatment, repeat angiography demonstrated patency of the parent vessel and complete obliteration of the aneurysm. Our case implies that Gamma Knife surgery (GKS) might serve as an alternative microinvasive technique in the treatment of LSA aneurysms, making this procedure a potential addition to present methods.

  6. Pros, cons, and current indications of open craniotomy versus gamma knife in the treatment of arteriovenous malformations and the role of endovascular embolization.

    PubMed

    Surdell, Daniel L; Bhattacharjee, Sumon; Loftus, Christopher M

    2002-06-01

    The successful treatment of an intracranial arteriovenous malformation poses both technical and conceptual problems to the neurosurgeon. Treatment decisions are made in light of current understanding of the natural history of these lesions. It is important to understand the pros, cons and current indication of open craniotomy vs. gamma knife in the treatment of arteriovenous malformations and the role of endovascular embolization. Surgical removal of an arteriovenous malformation is indicated when the operative risk is less than the morbidity and mortality associated with its natural history. The treatment goal of complete angiographic obliteration of arteriovenous malformations is achieved most effectively by microneurosurgery in low-grade lesions. Large lesions frequently require a combination of embolization and microsurgery. Although recent advances in technology and medical management have allowed previously inoperable arteriovenous malformations to be surgically excised, there is still a small group of arteriovenous malformations that cannot be excised safely due to their size and location. Stereotactic radiosurgery is clearly an important adjunct in the multimodality treatment approach for large arteriovenous malformations. Endovascular embolization can potentially increase safety and efficacy in the treatment of arteriovenous malformations when applied to selective cases with well-defined treatment goals.

  7. Gamma Knife surgery for clival epidural-osseous dural arteriovenous fistulas.

    PubMed

    Lee, Cheng-Chia; Chen, Ching-Jen; Chen, Shao-Ching; Yang, Huai-Che; Lin, Chung Jung; Wu, Chih-Chun; Chung, Wen-Yuh; Guo, Wan-Yuo; Hung-Chi Pan, David; Shiau, Cheng-Ying; Wu, Hsiu-Mei

    2018-05-01

    OBJECTIVE Clival epidural-osseous dural arteriovenous fistula (DAVF) is often associated with a large nidus, multiple arterial feeders, and complex venous drainage. In this study the authors report the outcomes of clival epidural-osseous DAVFs treated using Gamma Knife surgery (GKS). METHODS Thirteen patients with 13 clival epidural-osseous DAVFs were treated with GKS at the authors' institution between 1993 and 2015. Patient age at the time of GKS ranged from 38 to 76 years (median 55 years). Eight DAVFs were classified as Cognard Type I, 4 as Type IIa, and 1 as Type IIa+b. The median treatment volume was 17.6 cm 3 (range 6.2-40.3 cm 3 ). The median prescribed margin dose was 16.5 Gy (range 15-18 Gy). Clinical and radiological follow-ups were performed at 6-month intervals. Patient outcomes after GKS were categorized as 1) complete improvement, 2) partial improvement, 3) stationary, and 4) progression. RESULTS All 13 patients demonstrated symptomatic improvement, and on catheter angiography 12 of the 13 patients had complete obliteration and 1 patient had partial obliteration. The median follow-up period was 26 months (range 14-186 months). The median latency period from GKS to obliteration was 21 months (range 8-186 months). There was no intracranial hemorrhage during the follow-up period, and no deaths occurred. Two adverse events were observed following treatment, and 2 patients required repeat GKS treatment with eventual complete obliteration. CONCLUSIONS Gamma Knife surgery offers a safe and effective primary or adjuvant treatment modality for complex clival epidural-osseous DAVFs. All patients in this case series demonstrated symptomatic improvement, and almost all patients attained complete obliteration.

  8. Long-term safety and efficacy of stereotactic radiosurgery for vestibular schwannomas: evaluation of 440 patients more than 10 years after treatment with Gamma Knife surgery.

    PubMed

    Hasegawa, Toshinori; Kida, Yoshihisa; Kato, Takenori; Iizuka, Hiroshi; Kuramitsu, Shunichiro; Yamamoto, Takashi

    2013-03-01

    Object Little is known about long-term outcomes, including tumor control and adverse radiation effects, in patients harboring vestibular schwannomas (VSs) treated with stereotactic radiosurgery > 10 years previously. The aim of this study was to confirm whether Gamma Knife surgery (GKS) for VSs continues to be safe and effective > 10 years after treatment. Methods A total of 440 patients with VS (including neurofibromatosis Type 2) treated with GKS between May 1991 and December 2000 were evaluable. Of these, 347 patients (79%) underwent GKS as an initial treatment and 93 (21%) had undergone prior resection. Three hundred fifty-eight patients (81%) had a solid tumor and 82 (19%) had a cystic tumor. The median tumor volume was 2.8 cm(3) and the median marginal dose was 12.8 Gy. Results The median follow-up period was 12.5 years. The actuarial 5- and ≥ 10-year progression-free survival was 93% and 92%, respectively. No patient developed treatment failure > 10 years after treatment. According to multivariate analysis, significant factors related to worse progression-free survival included brainstem compression with a deviation of the fourth ventricle (p < 0.0001), marginal dose ≤ 13 Gy (p = 0.01), prior treatment (p = 0.02), and female sex (p = 0.02). Of 287 patients treated at a recent optimum dose of ≤ 13 Gy, 3 (1%) developed facial palsy, including 2 with transient palsy and 1 with persistent palsy after a second GKS, and 3 (1%) developed facial numbness, including 2 with transient and 1 with persistent facial numbness. The actuarial 10-year facial nerve preservation rate was 97% in the high marginal dose group (> 13 Gy) and 100% in the low marginal dose group (≤ 13 Gy). Ten patients (2.3%) developed delayed cyst formation. One patient alone developed malignant transformation, indicating an incidence of 0.3%. Conclusions In this study GKS was a safe and effective treatment for the majority of patients followed > 10 years after treatment. Special attention

  9. Linear Accelerator-Based Radiosurgery Alone for Arteriovenous Malformation: More Than 12 Years of Observation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Matsuo, Takayuki, E-mail: takayuki@nagasaki-u.ac.jp; Kamada, Kensaku; Izumo, Tsuyoshi

    Purpose: Although radiosurgery is an accepted treatment method for intracranial arteriovenous malformations (AVMs), its long-term therapeutic effects have not been sufficiently evaluated, and many reports of long-term observations are from gamma-knife facilities. Furthermore, there are few reported results of treatment using only linear accelerator (LINAC)-based radiosurgery (LBRS). Methods and Materials: Over a period of more than 12 years, we followed the long-term results of LBRS treatment performed in 51 AVM patients. Results: The actuarial obliteration rates, after a single radiosurgery session, at 3, 5, 10, and 15 years were 46.9%, 54.0%, 64.4%, and 68.0%, respectively; when subsequent radiosurgeries were included, themore » rates were 46.9%, 61.3%, 74.2%, and 90.3%, respectively. Obliteration rates were significantly related to target volumes ≥4 cm{sup 3}, marginal doses ≥12 Gy, Spetzler-Martin grades (1 vs other), and AVM scores ≥1.5; multivariate analyses revealed a significant difference for target volumes ≥4 cm{sup 3}. The postprocedural actuarial symptomatic radiation injury rates, after a single radiation surgery session, at 5, 10, and 15 years were 12.3%, 16.8%, and 19.1%, respectively. Volumes ≥4 cm{sup 3}, location (lobular or other), AVM scores ≥1.5, and the number of radiosurgery were related to radiation injury incidence; multivariate analyses revealed significant differences associated with volumes ≥4 cm{sup 3} and location (lobular or other). Conclusions: Positive results can be obtained with LBRS when performed with a target volume ≤4 cm{sup 3}, an AVM score ≤1.5, and ≥12 Gy radiation. Bleeding and radiation injuries may appear even 10 years after treatment, necessitating long-term observation.« less

  10. Do carbamazepine, gabapentin, or other anticonvulsants exert sufficient radioprotective effects to alter responses from trigeminal neuralgia radiosurgery?

    PubMed

    Flickinger, John C; Kim, Hyun; Kano, Hideyuki; Greenberger, Joel S; Arai, Yoshio; Niranjan, Ajay; Lunsford, L Dade; Kondziolka, Douglas; Flickinger, John C

    2012-07-15

    Laboratory studies have documented radioprotective effects with carbamazepine. We sought to determine whether carbamazepine or other anticonvulsant/neuroleptic drugs would show significant radioprotective effects in patients undergoing high-dose small-volume radiosurgery for trigeminal neuralgia. We conducted a retrospective review of 200 patients undergoing Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) stereotactic radiosurgery for trigeminal neuralgia between February 1995 and May 2008. We selected patients treated with a maximum dose of 80 Gy with 4-mm diameter collimators, with no previous microvascular decompression, and follow-up ≥6 months (median, 24 months; range, 6-153 months). At the time of radiosurgery, 28 patients were taking no anticonvulsants, 62 only carbamazepine, 35 only gabapentin, 21 carbamazepine plus gabapentin, 17 carbamazepine plus other anticonvulsants, and 9 gabapentin plus other anticonvulsants, and 28 were taking other anticonvulsants or combinations. Pain improvement developed post-radiosurgery in 187 of 200 patients (93.5%). Initial complete pain relief developed in 84 of 200 patients (42%). Post-radiosurgery trigeminal neuropathy developed in 27 of 200 patients (13.5%). We could not significantly correlate pain improvement or initial complete pain relief with use of carbamazepine, gabapentin, or use of any anticonvulsants/neuroleptic drugs or other factors in univariate or multivariate analysis. Post-radiosurgery numbness/paresthesias correlated with the use of gabapentin (1 of 36 patients with gabapentin vs. 7 of 28 without, p = 0.017). In multivariate analysis, decreasing age, purely typical pain, and use of gabapentin correlated (p = 0.008, p = 0.005, and p = 0.021) with lower risks of developing post-radiosurgery trigeminal neuropathy. New post-radiosurgery numbness/paresthesias developed in 3% (1 of 36), 5% (4 of 81), and 13% (23 of 187) of patients on gabapentin alone, with age ≤70 years, and Type 1 typical

  11. Do Carbamazepine, Gabapentin, or Other Anticonvulsants Exert Sufficient Radioprotective Effects to Alter Responses From Trigeminal Neuralgia Radiosurgery?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Flickinger, John C.; College of Arts and Sciences, University of Pittsburgh, Pittsburgh, PA; Kim, Hyun

    2012-07-15

    Purpose: Laboratory studies have documented radioprotective effects with carbamazepine. We sought to determine whether carbamazepine or other anticonvulsant/neuroleptic drugs would show significant radioprotective effects in patients undergoing high-dose small-volume radiosurgery for trigeminal neuralgia. Methods and Materials: We conducted a retrospective review of 200 patients undergoing Gamma Knife (Elekta Instrument AB, Stockholm, Sweden) stereotactic radiosurgery for trigeminal neuralgia between February 1995 and May 2008. We selected patients treated with a maximum dose of 80 Gy with 4-mm diameter collimators, with no previous microvascular decompression, and follow-up {>=}6 months (median, 24 months; range, 6-153 months). At the time of radiosurgery, 28 patientsmore » were taking no anticonvulsants, 62 only carbamazepine, 35 only gabapentin, 21 carbamazepine plus gabapentin, 17 carbamazepine plus other anticonvulsants, and 9 gabapentin plus other anticonvulsants, and 28 were taking other anticonvulsants or combinations. Results: Pain improvement developed post-radiosurgery in 187 of 200 patients (93.5%). Initial complete pain relief developed in 84 of 200 patients (42%). Post-radiosurgery trigeminal neuropathy developed in 27 of 200 patients (13.5%). We could not significantly correlate pain improvement or initial complete pain relief with use of carbamazepine, gabapentin, or use of any anticonvulsants/neuroleptic drugs or other factors in univariate or multivariate analysis. Post-radiosurgery numbness/paresthesias correlated with the use of gabapentin (1 of 36 patients with gabapentin vs. 7 of 28 without, p = 0.017). In multivariate analysis, decreasing age, purely typical pain, and use of gabapentin correlated (p = 0.008, p = 0.005, and p = 0.021) with lower risks of developing post-radiosurgery trigeminal neuropathy. New post-radiosurgery numbness/paresthesias developed in 3% (1 of 36), 5% (4 of 81), and 13% (23 of 187) of patients on gabapentin alone

  12. Robotic Radiosurgery for Adrenal Gland Metastases

    PubMed Central

    Heidorn, Sarah-Charlotta; Kremer, Nikolaus; Muacevic, Alexander; Fürweger, Christoph

    2017-01-01

    Introduction The purpose of this study was to investigate the safety and efficacy of CyberKnife (CK) robotic radiosurgery for treatment of adrenal metastases. Methods We performed a retrospective analysis of 23 patients with adrenal metastases who had been treated with CK between October 2006 and December 2015. Fifteen patients received chemotherapy prior to radiosurgery, all patients underwent computer tomography (CT) fluoroscopically guided percutaneous placement of one to three gold fiducials into the adrenal gland. Nineteen patients were selected for single-fraction radiosurgery with a median dose of 22 Gy, four patients were treated in three fractions with a median dose of 13.5 Gy. Results Median follow-up time was 23.6 months. Four patients (17%) experienced local relapse during the evaluation period with a mean time of 19 months to tumor progression. The actuarial local tumor control rate was 95% after one year and 81% after two years. Three of the four patients with local recurrence were retreated with CK radiosurgery. Dynamic tumor tracking enabled accurate treatment with correlation errors less than 2 mm, despite extensive respiration-induced target motion up to 22 mm. Apart from nausea directly after treatment in five patients, we observed no early or late treatment-related side effects. Conclusions Single fraction robotic radiosurgery for adrenal gland metastases is a safe and effective treatment option for patients who are not eligible for surgical resection. PMID:28451479

  13. RT-23THE ROLE OF GAMMA KNIFE RADIOSURGERY IN THE TREATMENT FOR PRIMARY CENTRAL NERVOUS SYSTEM LYMPHOMAS

    PubMed Central

    Mori, Kanji; Chiba, Yasuyoshi; Toyota, Shingo; Kumagai, Tetsuya; Yamamoto, Shota; Sugano, Hirohumi; Taki, Takuyu

    2014-01-01

    To evaluate the role of gamma knife (GK) as a treatment modality for primary central nervous system lymphomas (PCNSL), we reviewed PCNSL patients who were treated with GK between November 2004 and May 2014, retrospectively. There were 29 cases (13 males and 16 females, ranged from 33 years old to 91 years old) with 210 treated lesions. Marginal dose was from 12Gy to 18 Gy. One hundred and nineteen lesions of 23 cases could be accessed and all of them showed partial response or complete response. In seven cases, GK was performed at initial treatment, in 18 cases at recurrence, and in four cases at both. Median age of initial treatment group were significantly higher than that of recurred group (77.8 y.o. and 63.6 y.o., p = 0.00268). Two cases of initial treatment group and 16 cases of recurrent group were treated with whole brain radiation therapy (WBRT). GK after first relapse, progression free survival more than six months were obtained for six cases (33.3%), and four of them were free from additional therapy more than one year. Otherwise, thirteen cases (59.1%) received GK repeatedly (2-6 times, median = 3), and interval between each therapy was from 22 to 513 days (median = 93days). We confirmed that GK has high potential for local control. And it was supposed that GK was used as an alternative to WBRT at initial treatment for elderly, or selected to recurrent cases after WBRT. These results showed the role of GK in the treatment for PCNSL is palliative care, now in Japan. But it is clear that there exist patients who can live longer without WBRT by GK. We conclude that GK will become to play a more positive role by modifying its timing and modalities used together.

  14. Feasibility Study on Applying Radiophotoluminescent Glass Dosimeters for CyberKnife SRS Dose Verification

    PubMed Central

    Hsu, Shih-Ming; Hung, Chao-Hsiung; Liao, Yi-Jen; Fu, Hsiao-Mei; Tsai, Jo-Ting

    2017-01-01

    CyberKnife is one of multiple modalities for stereotactic radiosurgery (SRS). Due to the nature of CyberKnife and the characteristics of SRS, dose evaluation of the CyberKnife procedure is critical. A radiophotoluminescent glass dosimeter was used to verify the dose accuracy for the CyberKnife procedure and validate a viable dose verification system for CyberKnife treatment. A radiophotoluminescent glass dosimeter, thermoluminescent dosimeter, and Kodak EDR2 film were used to measure the lateral dose profile and percent depth dose of CyberKnife. A Monte Carlo simulation for dose verification was performed using BEAMnrc to verify the measured results. This study also used a radiophotoluminescent glass dosimeter coupled with an anthropomorphic phantom to evaluate the accuracy of the dose given by CyberKnife. Measurements from the radiophotoluminescent glass dosimeter were compared with the results of a thermoluminescent dosimeter and EDR2 film, and the differences found were less than 5%. The radiophotoluminescent glass dosimeter has some advantages in terms of dose measurements over CyberKnife, such as repeatability, stability, and small effective size. These advantages make radiophotoluminescent glass dosimeters a potential candidate dosimeter for the CyberKnife procedure. This study concludes that radiophotoluminescent glass dosimeters are a promising and reliable dosimeter for CyberKnife dose verification with clinically acceptable accuracy within 5%. PMID:28046056

  15. The role of diffusion tensor imaging tractography for Gamma Knife thalamotomy planning.

    PubMed

    Gomes, João Gabriel Ribeiro; Gorgulho, Alessandra Augusta; de Oliveira López, Amanda; Saraiva, Crystian Wilian Chagas; Damiani, Lucas Petri; Pássaro, Anderson Martins; Salvajoli, João Victor; de Oliveira Siqueira, Ludmila; Salvajoli, Bernardo Peres; De Salles, Antônio Afonso Ferreira

    2016-12-01

    OBJECTIVE The role of tractography in Gamma Knife thalamotomy (GK-T) planning is still unclear. Pyramidal tractography might reduce the risk of radiation injury to the pyramidal tract and reduce motor complications. METHODS In this study, the ventralis intermedius nucleus (VIM) targets of 20 patients were bilaterally defined using Iplannet Stereotaxy Software, according to the anterior commissure-posterior commissure (AC-PC) line and considering the localization of the pyramidal tract. The 40 targets and tractography were transferred as objects to the GammaPlan Treatment Planning System (GP-TPS). New targets were defined, according to the AC-PC line in the functional targets section of the GP-TPS. The target offsets required to maintain the internal capsule (IC) constraint of < 15 Gy were evaluated. In addition, the strategies available in GP-TPS to maintain the minimum conventional VIM target dose at > 100 Gy were determined. RESULTS A difference was observed between the positions of both targets and the doses to the IC. The lateral (x) and the vertical (z) coordinates were adjusted 1.9 mm medially and 1.3 mm cranially, respectively. The targets defined considering the position of the pyramidal tract were more medial and superior, based on the constraint of 15 Gy touching the object representing the IC in the GP-TPS. The best strategy to meet the set constraints was 90° Gamma angle (GA) with automatic shaping of dose distribution; this was followed by 110° GA. The worst GA was 70°. Treatment time was substantially increased by the shaping strategy, approximately doubling delivery time. CONCLUSIONS Routine use of DTI pyramidal tractography might be important to fine-tune GK-T planning. DTI tractography, as well as anisotropy showing the VIM, promises to improve Gamma Knife functional procedures. They allow for a more objective definition of dose constraints to the IC and targeting. DTI pyramidal tractography introduced into the treatment planning may reduce the

  16. A Long Term Follow Up After Radiosurgery Of Papillary Tumour Of The Pineal Region (Ptpr): Two Cases Report And Review Of The Literature.

    PubMed

    Fernández-Mateos, Cecilia; Martinez, Roberto; Vaquero, Jesús

    2018-05-19

    Tumours of the pineal region are rare in adulthood, accounting for approximately 1% of intracranial neoplasms in this age range. Because of their rarity, it has proven to be difficult to establish the optimal therapy. Furthermore, microsurgical total resection in this eloquent location is associated with not low rates of morbidity. We described two patients diagnosed of papillary tumours of the pineal region (PTPR) by stereotactic biopsy and referred for gamma knife radiosurgery after shunting for hydrocephalus. We are reporting a long-term follow up of 15 and 20 years respectively, showing a good response to the treatment. Copyright © 2018. Published by Elsevier Inc.

  17. A round-robin gamma stereotactic radiosurgery dosimetry interinstitution comparison of calibration protocols

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Drzymala, R. E., E-mail: drzymala@wustl.edu; Alvarez, P. E.; Bednarz, G.

    2015-11-15

    Purpose: Absorbed dose calibration for gamma stereotactic radiosurgery is challenging due to the unique geometric conditions, dosimetry characteristics, and nonstandard field size of these devices. Members of the American Association of Physicists in Medicine (AAPM) Task Group 178 on Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance have participated in a round-robin exchange of calibrated measurement instrumentation and phantoms exploring two approved and two proposed calibration protocols or formalisms on ten gamma radiosurgery units. The objectives of this study were to benchmark and compare new formalisms to existing calibration methods, while maintaining traceability to U.S. primary dosimetry calibration laboratory standards. Methods:more » Nine institutions made measurements using ten gamma stereotactic radiosurgery units in three different 160 mm diameter spherical phantoms [acrylonitrile butadiene styrene (ABS) plastic, Solid Water, and liquid water] and in air using a positioning jig. Two calibrated miniature ionization chambers and one calibrated electrometer were circulated for all measurements. Reference dose-rates at the phantom center were determined using the well-established AAPM TG-21 or TG-51 dose calibration protocols and using two proposed dose calibration protocols/formalisms: an in-air protocol and a formalism proposed by the International Atomic Energy Agency (IAEA) working group for small and nonstandard radiation fields. Each institution’s results were normalized to the dose-rate determined at that institution using the TG-21 protocol in the ABS phantom. Results: Percentages of dose-rates within 1.5% of the reference dose-rate (TG-21 + ABS phantom) for the eight chamber-protocol-phantom combinations were the following: 88% for TG-21, 70% for TG-51, 93% for the new IAEA nonstandard-field formalism, and 65% for the new in-air protocol. Averages and standard deviations for dose-rates over all measurements relative to the TG

  18. Stereotactic Radiosurgery for Trigeminal Neuralgia in Patients With Multiple Sclerosis: A Multicenter Study.

    PubMed

    Xu, Zhiyuan; Mathieu, David; Heroux, France; Abbassy, Mahmoud; Barnett, Gene; Mohammadi, Alireza M; Kano, Hideyuki; Caruso, James; Shih, Han-Hsun; Grills, Inga S; Lee, Kuei; Krishnan, Sandeep; Kaufmann, Anthony M; Lee, John Y K; Alonso-Basanta, Michelle; Kerr, Marie; Pierce, John; Kondziolka, Douglas; Hess, Judith A; Gerrard, Jason; Chiang, Veronica; Lunsford, L Dade; Sheehan, Jason P

    2018-04-23

    Facial pain response (PR) to various surgical interventions in patients with multiple sclerosis (MS)-related trigeminal neuralgia (TN) is much less optimal. No large patient series regarding stereotactic radiosurgery (SRS) has been published. To evaluate the clinical outcomes of MS-related TN treated with SRS. This is a retrospective cohort study. A total of 263 patients contributed by 9 member tertiary referral Gamma Knife centers (2 in Canada and 7 in USA) of the International Gamma Knife Research Consortium (IGKRF) constituted this study. The median latency period of PR after SRS was 1 mo. Reasonable pain control (Barrow Neurological Institute [BNI] Pain Scores I-IIIb) was achieved in 232 patients (88.2%). The median maintenance period from SRS was 14.1 months (range, 10 days to 10 years). The actuarial reasonable pain control maintenance rates at 1 yr, 2 yr, and 4 yr were 54%, 35%, and 24%, respectively. There was a correlation between the status of achieving BNI-I and the maintenance of facial pain recurrence-free rate. The median recurrence-free rate was 36 mo and 12.2 mo in patients achieving BNI-I and BNI > I, respectively (P = .046). Among 210 patients with known status of post-SRS complications, the new-onset of facial numbness (BNI-I or II) after SRS occurred in 21 patients (10%). In this largest series SRS offers a reasonable benefit to risk profile for patients who have exhausted medical management. More favorable initial response to SRS may predict a long-lasting pain control.

  19. Linear accelerator stereotactic radiosurgery for trigeminal neuralgia.

    PubMed

    Varela-Lema, Leonor; Lopez-Garcia, Marisa; Maceira-Rozas, Maria; Munoz-Garzon, Victor

    2015-01-01

    Stereotactic radiosurgery is accepted as an alternative for patients with refractory trigeminal neuralgia, but existing evidence is fundamentally based on the Gamma Knife, which is a specific device for intracranial neurosurgery, available in few facilities. Over the last decade it has been shown that the use of linear accelerators can achieve similar diagnostic accuracy and equivalent dose distribution. To assess the effectiveness and safety of linear-accelerator stereotactic radiosurgery for the treatment of patients with refractory trigeminal neuralgia. We carried out a systematic search of the literature in the main electronic databases (PubMed, Embase, ISI Web of Knowledge, Cochrane, Biomed Central, IBECS, IME, CRD) and reviewed grey literature. All original studies on the subject published in Spanish, French, English, and Portuguese were eligible for inclusion. The selection and critical assessment was carried out by 2 independent reviewers based on pre-defined criteria. In view of the impossibility of carrying out a pooled analysis, data were analyzed in a qualitative way. Eleven case series were included. In these, satisfactory pain relief (BIN I-IIIb or reduction in pain = 50) was achieved in 75% to 95.7% of the patients treated. The mean time to relief from pain ranged from 8.5 days to 3.8 months. The percentage of patients who presented with recurrences after one year of follow-up ranged from 5% to 28.8%. Facial swelling or hypoesthesia, mostly of a mild-moderate grade appeared in 7.5% - 51.9% of the patients. Complete anaesthesia dolorosa was registered in only study (5.3%). Cases of hearing loss (2.5%), brainstem edema (5.8%), and neurotrophic keratoplasty (3.5%) were also isolated. The results suggest that stereotactic radiosurgery with linear accelerators could constitute an effective and safe therapeutic alternative for drug-resistant trigeminal neuralgia. However, existing studies leave important doubts as to optimal treatment doses or the

  20. SU-F-T-370: A Fast Monte Carlo Dose Engine for Gamma Knife

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, T; Zhou, L; Li, Y

    2016-06-15

    Purpose: To develop a fast Monte Carlo dose calculation algorithm for Gamma Knife. Methods: To make the simulation more efficient, we implemented the track repeating technique on GPU. We first use EGSnrc to pre-calculate the photon and secondary electron tracks in water from two mono-energy photons of 60Co. The total photon mean free paths for different materials and energies are obtained from NIST. During simulation, each entire photon track was first loaded to shared memory for each block, the incident original photon was then splitted to Nthread sub-photons, each thread transport one sub-photon, the Russian roulette technique was applied formore » scattered and bremsstrahlung photons. The resultant electrons from photon interactions are simulated by repeating the recorded electron tracks. The electron step length is stretched/shrunk proportionally based on the local density and stopping power ratios of the local material. Energy deposition in a voxel is proportional to the fraction of the equivalent step length in that voxel. To evaluate its accuracy, dose deposition in a 300mm*300mm*300mm water phantom is calculated, and compared to EGSnrc results. Results: Both PDD and OAR showed great agreements (within 0.5%) between our dose engine result and the EGSnrc result. It only takes less than 1 min for every simulation, being reduced up to ∼40 times compared to EGSnrc simulations. Conclusion: We have successfully developed a fast Monte Carlo dose engine for Gamma Knife.« less

  1. Prediction of obliteration after gamma knife surgery for cerebral arteriovenous malformations.

    PubMed

    Karlsson, B; Lindquist, C; Steiner, L

    1997-03-01

    To define the factors of importance for the obliteration of cerebral arteriovenous malformations (AVMs), thus making a prediction of the probability for obliteration possible. In 945 AVMs of a series of 1319 patients treated with the gamma knife during 1970 to 1990, the relationship between patient, AVMs, and treatment parameters on the one hand and the obliteration of the nidus on the other was analyzed. The obliteration rate increased both with increased minimum (lowest periphery) and average dose and decreased with increased AVM volume. The minimum dose to the AVMs was the decisive dose factor for the treatment result. The higher the minimum dose, the higher the chance for total obliteration. The curve illustrating this relation increased logarithmically to a value of 87%. A higher average dose shortened the latency to AVM obliteration. For the obliterated cases, the larger the malformation, the lower the minimum dose used. This prompted us to relate the obliteration rate to the product minimum dose (AVM volume)1/3 (K index). The obliteration rate increased linearly with the K index up to a value of approximately 27, and for higher K values, the obliteration rate had a constant value of approximately 80%. For the group of 273 cases treated with a minimum dose of at least 25 Gy, the obliteration rate at the study end point (defined as 2-yr latency) was 80% (95% confidence interval = 75-85%). If obliterations that occurred beyond the end point are included, the obliteration rate increased to 85% (81-89%). The probability of obliteration of AVMs after gamma knife surgery is related both to the lowest dose to the AVMs and the AVM volume, and it can be predicted using the K index.

  2. A simplified model of the source channel of the Leksell GammaKnife tested with PENELOPE.

    PubMed

    Al-Dweri, Feras M O; Lallena, Antonio M; Vilches, Manuel

    2004-06-21

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife. The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3 degrees with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, v, z = 236 mm) show strong correlations between rho = (x2 + y2)(1/2) and their polar angle theta, on one side, and between tan(-1)(y/x) and their azimuthal angle phi, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time.

  3. Adaptive fractionated stereotactic Gamma Knife radiotherapy of meningioma using integrated stereotactic cone-beam-CT and adaptive re-planning (a-gkFSRT).

    PubMed

    Stieler, F; Wenz, F; Abo-Madyan, Y; Schweizer, B; Polednik, M; Herskind, C; Giordano, F A; Mai, S

    2016-11-01

    The Gamma Knife Icon (Elekta AB, Stockholm, Sweden) allows frameless stereotactic treatment using a combination of cone beam computer tomography (CBCT), a thermoplastic mask system, and an infrared-based high-definition motion management (HDMM) camera system for patient tracking during treatment. We report on the first patient with meningioma at the left petrous bone treated with adaptive fractionated stereotactic radiotherapy (a-gkFSRT). The first patient treated with Gamma Knife Icon at our institute received MR imaging for preplanning before treatment. For each treatment fraction, a daily CBCT was performed to verify the actual scull/tumor position. The system automatically adapted the planned shot positions to the daily position and recalculated the dose distribution (online adaptive planning). During treatment, the HDMM system recorded the intrafractional patient motion. Furthermore, the required times were recorded to define a clinical treatment slot. Total treatment time was around 20 min. Patient positioning needed 0.8 min, CBCT positioning plus acquisition 1.65 min, CT data processing and adaptive planning 2.66 min, and treatment 15.6 min. The differences for the five daily CBCTs compared to the reference are for rotation: -0.59 ± 0.49°/0.18 ± 0.20°/0.05 ± 0.36° and for translation: 0.94 ± 0.52 mm/-0.08 ± 0.08 mm/-1.13 ± 0.89 mm. Over all fractions, an intrafractional movement of 0.13 ± 0.04 mm was observed. The Gamma Knife Icon allows combining the accuracy of the stereotactic Gamma Knife system with the flexibility of fractionated treatment with the mask system and CBCT. Furthermore, the Icon system introduces a new online patient tracking system to the clinical routine. The interfractional accuracy of patient positioning was controlled with a thermoplastic mask and CBCT.

  4. Epilepsy related to hypothalamic hamartomas: surgical management with special reference to gamma knife surgery.

    PubMed

    Régis, Jean; Scavarda, Didier; Tamura, Manabu; Nagayi, Mariko; Villeneuve, Nathalie; Bartolomei, Fabrice; Brue, Thierry; Dafonseca, David; Chauvel, Patrick

    2006-08-01

    A large spectrum of surgical techniques can be proposed to young patients presenting with hypothalamic hamartomas (HH) associated with severe epilepsy. The aim of this report is to point on some clinical and anatomical parameters supposed to influence the choice of the surgical approach and to emphasize the specific role of radiosurgery. We reviewed both our experience and the recent literature based on a Pubmed search. Lateral pterional, midline frontal through the lamina terminalis, transcallosal interforniceal approaches, endoscopic treatment through the foramen of Monro, disconnecting surgery, radiofrequency ablation, brachytherapy and gamma knife surgery (GKS) were all considered. Mortality, morbidity, and efficacy of each of these techniques were compared. Specific limits, difficulties, and constraints were taken into account. Our experience of radiosurgery is based on a prospective trial which enrolled 60 patients with HH and associated severe epilepsy between October 1999 and December 2005. Several surgical techniques can lead to a real reversal of the epileptic encephalopathy. The main factors for the decision-making process are the age, the size of the lesion and its anatomical type (according to our original classification), the severity of the epilepsy, and the severity of the cognitive/psychiatric comorbidity. In our prospective trial (GKS), 27 patients have a follow-up superior to 3 years. Among those, 59.2% have an excellent result with a dramatic behavioral and cognitive improvement and are completely seizure-free (37%) or have only rare non-disabling seizures (22.2%). No permanent neurological complication has been observed so far; three patients have presented a transient poïkilothermia. GKS is clearly the safer approach for these difficult patients. Young patients with severe epilepsy and comorbidity must be operated on using a curative approach as early as possible. Very large type VI or mixed type with a large component above the floor of the

  5. Cone beam computed tomography image guidance system for a dedicated intracranial radiosurgery treatment unit.

    PubMed

    Ruschin, Mark; Komljenovic, Philip T; Ansell, Steve; Ménard, Cynthia; Bootsma, Gregory; Cho, Young-Bin; Chung, Caroline; Jaffray, David

    2013-01-01

    Image guidance has improved the precision of fractionated radiation treatment delivery on linear accelerators. Precise radiation delivery is particularly critical when high doses are delivered to complex shapes with steep dose gradients near critical structures, as is the case for intracranial radiosurgery. To reduce potential geometric uncertainties, a cone beam computed tomography (CT) image guidance system was developed in-house to generate high-resolution images of the head at the time of treatment, using a dedicated radiosurgery unit. The performance and initial clinical use of this imaging system are described. A kilovoltage cone beam CT system was integrated with a Leksell Gamma Knife Perfexion radiosurgery unit. The X-ray tube and flat-panel detector are mounted on a translational arm, which is parked above the treatment unit when not in use. Upon descent, a rotational axis provides 210° of rotation for cone beam CT scans. Mechanical integrity of the system was evaluated over a 6-month period. Subsequent clinical commissioning included end-to-end testing of targeting performance and subjective image quality performance in phantoms. The system has been used to image 2 patients, 1 of whom received single-fraction radiosurgery and 1 who received 3 fractions, using a relocatable head frame. Images of phantoms demonstrated soft tissue contrast visibility and submillimeter spatial resolution. A contrast difference of 35 HU was easily detected at a calibration dose of 1.2 cGy (center of head phantom). The shape of the mechanical flex vs scan angle was highly reproducible and exhibited <0.2 mm peak-to-peak variation. With a 0.5-mm voxel pitch, the maximum targeting error was 0.4 mm. Images of 2 patients were analyzed offline and submillimeter agreement was confirmed with conventional frame. A cone beam CT image guidance system was successfully adapted to a radiosurgery unit. The system is capable of producing high-resolution images of bone and soft tissue. The

  6. Initial experience with gamma knife surgery for endocrine ophthalmopathy.

    PubMed

    Antico, Julio C; Crovetto, Luis; Tenca, Eduardo; Artes, Carlos

    2005-01-01

    The aim of this study was to evaluate both the effectiveness and safety of the treatment of endocrine ophthalmopathy with gamma knife surgery (GKS). Five patients were included in a prospective study designed to assess the results of GKS of endocrine ophthalmopathy secondary to Graves disease. All the patients completed a 2-year follow-up period. During this period, the patients were evaluated both clinically and by means of additional methods, including computerized tomography and magnetic resonance imaging studies. The minimum dose delivered to the 50% isodose line was 6.5 Gy in all the patients. In all cases, a clinical improvement was observed. The best effect was seen in symptom regression related to soft-tissue involvement. No treatment-related side effects were detected. In light of the results obtained the authors consider that GKS may be a safe and effective way to treat endocrine ophthalmopathy.

  7. MR angiography fusion technique for treatment planning of intracranial arteriovenous malformations.

    PubMed

    McGee, Kiaran P; Ivanovic, Vladimir; Felmlee, Joel P; Meyer, Fredrick B; Pollock, Bruce E; Huston, John

    2006-03-01

    To develop an image fusion technique using elliptical centric contrast-enhanced (CE) MR angiography (MRA) and three-dimensional (3D) time-of-flight (TOF) acquisitions for radiosurgery treatment planning of arteriovenous malformations (AVMs). CE and 3D-TOF MR angiograms with disparate in-plane fields of view (FOVs) were acquired, followed by k-space reformatting to provide equal voxel dimensions. Spatial domain addition was performed to provide a third, fused data volume. Spatial distortion was evaluated on an MRA phantom and provided slice-dependent and global distortion along the three physical dimensions of the MR scanner. In vivo validation was performed on 10 patients with intracranial AVMs prior to their conventional angiogram on the day of gamma knife radiosurgery. Spatial distortion in the phantom within a volume of 14 x 14 x 3.2 cm(3) was less than +/-1 mm (+/-1 standard deviation (SD)) for CE and 3D-TOF data sets. Fused data volumes were successfully generated for all 10 patients. Image fusion can be used to obtain high-resolution CE-MRA images of intracranial AVMs while keeping the fiducial markers needed for gamma knife radiosurgery planning. The spatial fidelity of these data is within the tolerance acceptable for daily quality control (QC) purposes and gamma knife treatment planning. (c) 2006 Wiley-Liss, Inc.

  8. Progression of vestibular schawnnoma after GammaKnife radiosurgery: A challenge for microsurgical resection.

    PubMed

    Aboukaïs, Rabih; Bonne, Nicolas-Xavier; Touzet, Gustavo; Vincent, Christophe; Reyns, Nicolas; Lejeune, Jean-Paul

    2018-05-01

    We aimed to evaluate the outcome of patients who underwent salvage microsurgery for vestibular schwannoma (VS) that failed primary Gammaknife radiosurgery (GKS). Among the 1098 patients who received GKS for the treatment of VS in our center between January 2004 and December 2012, the follow-up was organized in our institution for 290 patients who lived in our recruitment area. Tumor progression was noted in 23 patients. A salvage microsurgical resection was performed in 11 patients, who were included in our study. Grading of facial function was done according to the House & Brackman scale. The mean age at diagnosis was 50.2 years (19-68 years) and the mean follow-up was 9.4 years (4-13 years). The mean dose was 11.8 Gy (11-12 Gy) and the mean volume was 922 mm3 (208-2500 mm3). The mean period between GKS and diagnosis of tumor progression was 32 months (18-72 months). Concerning salvage microsurgery, complete resection was obtained in 8 patients. Small residual tumor on the facial nerve was deliberately left in 3 patients and no tumor progression was noted with a mean follow-up of 26 months. At last follow-up, facial nerve function was grade 1 in 4 patients, grade 2 in 3 patients, grade 3 in 1 patient and grade 4 in 3 patients. Salvage surgery of recurrent vestibular schwannoma after failed initial GKS remains a good treatment. However, facial nerve preservation is more challenging in this case and small tumor remnant could be sometimes deliberately left. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. A simplified model of the source channel of the Leksell GammaKnife® tested with PENELOPE

    NASA Astrophysics Data System (ADS)

    Al-Dweri, Feras M. O.; Lallena, Antonio M.; Vilches, Manuel

    2004-06-01

    Monte Carlo simulations using the code PENELOPE have been performed to test a simplified model of the source channel geometry of the Leksell GammaKnife®. The characteristics of the radiation passing through the treatment helmets are analysed in detail. We have found that only primary particles emitted from the source with polar angles smaller than 3° with respect to the beam axis are relevant for the dosimetry of the Gamma Knife. The photon trajectories reaching the output helmet collimators at (x, y, z = 236 mm) show strong correlations between rgr = (x2 + y2)1/2 and their polar angle thgr, on one side, and between tan-1(y/x) and their azimuthal angle phgr, on the other. This enables us to propose a simplified model which treats the full source channel as a mathematical collimator. This simplified model produces doses in good agreement with those found for the full geometry. In the region of maximal dose, the relative differences between both calculations are within 3%, for the 18 and 14 mm helmets, and 10%, for the 8 and 4 mm ones. Besides, the simplified model permits a strong reduction (larger than a factor 15) in the computational time.

  10. Critical appraisal of RapidArc radiosurgery with flattening filter free photon beams for benign brain lesions in comparison to GammaKnife: a treatment planning study.

    PubMed

    Abacioglu, Ufuk; Ozen, Zeynep; Yilmaz, Meltem; Arifoglu, Alptekin; Gunhan, Basri; Kayalilar, Namik; Peker, Selcuk; Sengoz, Meric; Gurdalli, Salih; Cozzi, Luca

    2014-05-21

    To evaluate the role of RapidArc (RA) for stereotactic radiosurgery (SRS) of benign brain lesions in comparison to GammaKnife (GK) based technique. Twelve patients with vestibular schwannoma (VS, n = 6) or cavernous sinus meningioma (CSM, n = 6) were planned for both SRS using volumetric modulated arc therapy (VMAT) by RA. 104 MV flattening filter free photon beams with a maximum dose rate of 2400 MU/min were selected. Data were compared against plans optimised for GK. A single dose of 12.5 Gy was prescribed. The primary objective was to assess treatment plan quality. Secondary aim was to appraise treatment efficiency. For VS, comparing best GK vs. RA plans, homogeneity was 51.7 ± 3.5 vs. 6.4 ± 1.5%; Paddick conformity Index (PCI) resulted 0.81 ± 0.03 vs. 0.84 ± 0.04. Gradient index (PGI) was 2.7 ± 0.2 vs. 3.8 ± 0.6. Mean target dose was 17.1 ± 0.9 vs. 12.9 ± 0.1 Gy. For the brain stem, D(1cm3) was 5.1 ± 2.0 Gy vs 4.8 ± 1.6 Gy. For the ipsilateral cochlea, D(0.1cm3) was 1.7 ± 1.0 Gy vs. 1.8 ± 0.5 Gy. For CSM, homogeneity was 52.3 ± 2.4 vs. 12.4 ± 0.6; PCI: 0.86 ± 0.05 vs. 0.88 ± 0.05; PGI: 2.6 ± 0.1 vs. 3.8 ± 0.5; D(1cm3) to brain stem was 5.4 ± 2.8 Gy vs. 5.2 ± 2.8 Gy; D(0.1cm3) to ipsi-lateral optic nerve was 4.2 ± 2.1 vs. 2.1 ± 1.5 Gy; D(0.1cm3) to optic chiasm was 5.9 ± 3.1 vs. 4.5 ± 2.1 Gy. Treatment time was 53.7 ± 5.8 (64.9 ± 24.3) minutes for GK and 4.8 ± 1.3 (5.0 ± 0.7) minutes for RA for schwannomas (meningiomas). SRS with RA and FFF beams revealed to be adequate and comparable to GK in terms of target coverage, homogeneity, organs at risk sparing with some gain in terms of treatment efficiency.

  11. Critical appraisal of RapidArc radiosurgery with flattening filter free photon beams for benign brain lesions in comparison to GammaKnife: a treatment planning study

    PubMed Central

    2014-01-01

    Background To evaluate the role of RapidArc (RA) for stereotactic radiosurgery (SRS) of benign brain lesions in comparison to GammaKnife (GK) based technique. Methods Twelve patients with vestibular schwannoma (VS, n = 6) or cavernous sinus meningioma (CSM, n = 6) were planned for both SRS using volumetric modulated arc therapy (VMAT) by RA. 104 MV flattening filter free photon beams with a maximum dose rate of 2400 MU/min were selected. Data were compared against plans optimised for GK. A single dose of 12.5 Gy was prescribed. The primary objective was to assess treatment plan quality. Secondary aim was to appraise treatment efficiency. Results For VS, comparing best GK vs. RA plans, homogeneity was 51.7 ± 3.5 vs. 6.4 ± 1.5%; Paddick conformity Index (PCI) resulted 0.81 ± 0.03 vs. 0.84 ± 0.04. Gradient index (PGI) was 2.7 ± 0.2 vs. 3.8 ± 0.6. Mean target dose was 17.1 ± 0.9 vs. 12.9 ± 0.1 Gy. For the brain stem, D1cm3 was 5.1 ± 2.0 Gy vs 4.8 ± 1.6 Gy. For the ipsilateral cochlea, D0.1cm3 was 1.7 ± 1.0 Gy vs. 1.8 ± 0.5 Gy. For CSM, homogeneity was 52.3 ± 2.4 vs. 12.4 ± 0.6; PCI: 0.86 ± 0.05 vs. 0.88 ± 0.05; PGI: 2.6 ± 0.1 vs. 3.8 ± 0.5; D1cm3 to brain stem was 5.4 ± 2.8 Gy vs. 5.2 ± 2.8 Gy; D0.1cm3 to ipsi-lateral optic nerve was 4.2 ± 2.1 vs. 2.1 ± 1.5 Gy; D0.1cm3 to optic chiasm was 5.9 ± 3.1 vs. 4.5 ± 2.1 Gy. Treatment time was 53.7 ± 5.8 (64.9 ± 24.3) minutes for GK and 4.8 ± 1.3 (5.0 ± 0.7) minutes for RA for schwannomas (meningiomas). Conclusions SRS with RA and FFF beams revealed to be adequate and comparable to GK in terms of target coverage, homogeneity, organs at risk sparing with some gain in terms of treatment efficiency. PMID:24884967

  12. SU-E-T-86: A Systematic Method for GammaKnife SRS Fetal Dose Estimation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Geneser, S; Paulsson, A; Sneed, P

    Purpose: Estimating fetal dose is critical to the decision-making process when radiation treatment is indicated during pregnancy. Fetal doses less than 5cGy confer no measurable non-cancer developmental risks but can produce a threefold increase in developing childhood cancer. In this study, we estimate fetal dose for a patient receiving Gamma Knife stereotactic radiosurgery (GKSRS) treatment and develop a method to estimate dose directly from plan details. Methods: A patient underwent GKSRS on a Perfexion unit for eight brain metastases (two infratentorial and one brainstem). Dose measurements were performed using a CC13, head phantom, and solid water. Superficial doses to themore » thyroid, sternum, and pelvis were measured using MOSFETs during treatment. Because the fetal dose was too low to accurately measure, we obtained measurements proximally to the isocenter, fitted to an exponential function, and extrapolated dose to the fundus of the uterus, uterine midpoint, and pubic synthesis for both the preliminary and delivered plans. Results: The R-squared fit for the delivered doses was 0.995. The estimated fetal doses for the 72 minute preliminary and 138 minute delivered plans range from 0.0014 to 0.028cGy and 0.07 to 0.38cGy, respectively. MOSFET readings during treatment were just above background for the thyroid and negligible for all inferior positions. The method for estimating fetal dose from plan shot information was within 0.2cGy of the measured values at 14cm cranial to the fetal location. Conclusion: Estimated fetal doses for both the preliminary and delivered plan were well below the 5cGy recommended limit. Due to Pefexion shielding, internal dose is primarily governed by attenuation and drops off exponentially. This is the first work that reports fetal dose for a GK Perfexion unit. Although multiple lesions were treated and the duration of treatment was long, the estimated fetal dose remained very low.« less

  13. Gamma knife surgery for brainstem arteriovenous malformations.

    PubMed

    Yen, Chun-Po; Steiner, Ladislau

    2011-01-01

    To evaluate the long-term imaging and clinical outcomes of patients with brainstem arteriovenous malformations (AVMs) treated with Gamma Knife surgery (GKS). The study included 85 patients with brainstem AVMs undergoing GKS during the period 1989-2007. The locations of the nidi were the midbrain in 42 patients, pons in 31 patients, and medulla oblongata in 12 patients. The volume of the nidi ranged from 0.1-8.9 mL (median 1.4 mL, mean 1.9 mL), and the prescription dose ranged from 5-32 Gy (median 20 Gy, mean 19.9 Gy). After the initial Gamma procedure, 18 patients had repeat GKS for AVM residuals that were still patent. Two patients had a third GKS 7 years and 16 years after a failed repeat GKS. Clinical follow-up ranged from 24-252 months with a mean of 100 months (median 102 months) after the initial GKS. GKS yielded a total angiographic obliteration in 50 (58.8%) patients and subtotal obliteration in 4 (4.7%) patients. In 22 (25.9%) patients, the AVMs remained patent. In 9 patients (10.6%), no flow voids were observed on magnetic resonance imaging (MRI), but angiographic confirmation was unavailable. A small nidus volume and a high prescription dose were significantly associated with increased AVM obliteration rate. Radiation-induced changes developed in 34 patients (40%); 24 were asymptomatic, 1 patient had only headache, and 9 patients developed neurologic deficits. One patient developed a large cyst 6 years after GKS. Given the poor surgical outcome of brainstem AVMs, the results of 59% nidus obliteration and 6% permanent neurologic deficits make GKS a reasonable management of these difficult lesions. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Retrospective analysis of imaging techniques for treatment planning and monitoring of obliteration for gamma knife treatment of cerebral arteriovenous malformation.

    PubMed

    Amponsah, Kwame; Ellis, Thomas L; Chan, Michael D; Lovato, James F; Bourland, J Daniel; deGuzman, Allan F; Ekstrand, Kenneth E; Munley, Michael T; McMullen, Kevin P; Shaw, Edward G; Tatter, Stephen B

    2012-10-01

    It has been well established that Gamma Knife radiosurgery (GKS) is an effective treatment for brain arteriovenous malformations (AVMs). To evaluate complete obliteration rates for magnetic resonance imaging (MRI)-based GKS treatment planning performed with and without angiography and to conduct a preliminary assessment of the utility of using pulsed arterial spin labeling (PASL) magnetic resonance (MR) perfusion imaging to confirm complete obliteration. Forty-six patients were identified who had undergone GKS without embolization with a minimum follow-up of 2 years. One group was planned with integrated stereotactic angiography and MR (spoiled gradient recalled) images obtained on the day of GKS. A second technique avoided the risk of arteriography by using only axial MR images. Beginning in 2007, PASL MR perfusion imaging was routinely performed as a portion of the follow-up MRI to assess the restoration of normal blood flow of the nidus and surrounding area. The overall obliteration rate for the angiography/MRI group was 88.0% (29 of 33). Patients in the MRI-only group had an obliteration rate of 61.5% (8 of 13), with P=.092 with the Fisher exact test, which is not statistically significant. A Kaplan-Meier analysis was also not statistically significant (log rank test, P=.474). Four of 9 patients with incomplete obliteration on angiography also had shown residual abnormal blood flow on PASL imaging. This retrospective analysis shows that treatment planning technique used in GKS does not play a role in the eventual obliteration of treated AVMs. PASL may have potential in the evaluation of AVM obliteration.

  15. Plan delivery quality assurance for CyberKnife: Statistical process control analysis of 350 film-based patient-specific QAs.

    PubMed

    Bellec, J; Delaby, N; Jouyaux, F; Perdrieux, M; Bouvier, J; Sorel, S; Henry, O; Lafond, C

    2017-07-01

    Robotic radiosurgery requires plan delivery quality assurance (DQA) but there has never been a published comprehensive analysis of a patient-specific DQA process in a clinic. We proposed to evaluate 350 consecutive film-based patient-specific DQAs using statistical process control. We evaluated the performance of the process to propose achievable tolerance criteria for DQA validation and we sought to identify suboptimal DQA using control charts. DQAs were performed on a CyberKnife-M6 using Gafchromic-EBT3 films. The signal-to-dose conversion was performed using a multichannel-correction and a scanning protocol that combined measurement and calibration in a single scan. The DQA analysis comprised a gamma-index analysis at 3%/1.5mm and a separate evaluation of spatial and dosimetric accuracy of the plan delivery. Each parameter was plotted on a control chart and control limits were calculated. A capability index (Cpm) was calculated to evaluate the ability of the process to produce results within specifications. The analysis of capability showed that a gamma pass rate of 85% at 3%/1.5mm was highly achievable as acceptance criteria for DQA validation using a film-based protocol (Cpm>1.33). 3.4% of DQA were outside a control limit of 88% for gamma pass-rate. The analysis of the out-of-control DQA helped identify a dosimetric error in our institute for a specific treatment type. We have defined initial tolerance criteria for DQA validations. We have shown that the implementation of a film-based patient-specific DQA protocol with the use of control charts is an effective method to improve patient treatment safety on CyberKnife. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  16. An Open-Label, Analgesic Efficacy and Safety of Pituitary Radiosurgery for Patients With Opioid-Refractory Pain: Study Protocol for a Randomized Controlled Trial.

    PubMed

    Borius, Pierre-Yves; Garnier, Stéphanie Ranque; Baumstarck, Karine; Castinetti, Frédéric; Donnet, Anne; Guedj, Eric; Cornu, Philippe; Blond, Serge; Salas, Sébastien; Régis, Jean

    2017-08-02

    Hypophysectomy performed by craniotomy or percutaneous techniques leads to complete pain relief in more than 70% to 80% of cases for opioid refractory cancer pain. Radiosurgery could be an interesting alternative approach to reduce complications. To assess the analgesic efficacy compared with standard of care is the primary goal. The secondary objectives are to assess ophthalmic and endocrine tolerance, drug consumption, quality of life, and mechanisms of analgesic action. The trial is multicenter, randomized, prospective, and open-label with 2 parallel groups. This concerns patients in palliative care suffering from nociceptive or mixed cancer pain, refractory to standard opioid therapy. Participants will be randomly assigned to the control group receiving standards of care for pain according to recommendations, or to the experimental group receiving a pituitary GammaKnife (Elekta, Stockholm, Sweden) radiosurgery (160 Gy delivered in pituitary gland) associated with standards of care. Evaluation assessments will be taken at baseline, day0, day4, day7, day14, day28, day45, month3, and month6. We could expect pain improvement in 70% to 90% of cases at day4. In addition we will assess the safety of pituitary radiosurgery in a vulnerable population. The secondary endpoints could show decay of opioid consumption, good patient satisfaction, and improvement of the quality of life. The design of this study is potentially the most appropriate to demonstrate the efficacy and safety of radiosurgery for this new indication. New recommendations could be obtained in order to improve pain relief and quality of life. Copyright © 2017 by the Congress of Neurological Surgeons

  17. Application of the concept of biologically effective dose (BED) to patients with Vestibular Schwannomas treated by radiosurgery

    PubMed Central

    Millar, William T.; Lindquist, Christer; Nordström, Håkan; Lidberg, Pär; Gårding, Jonas

    2013-01-01

    In the application of stereotactic radiosurgery, using the Gamma Knife, there are large variations in the overall treatment time for the same prescription dose, given in a single treatment session, for different patients. This is due to not only changes in the activity of the Cobolt-60 sources, but also to variations in the number of iso-centers used, the collimator size for a particular iso-center, and the time gap between the different iso-centers. Although frequently viewed as a single dose treatment the concept of biologically effective dose (BED), incorporating concurrent fast and a slow components of repair of sublethal damage, would imply potential variations in BED because of the influence of these different variables associated with treatment. This was investigated in 26 patients, treated for Vestibular Schwannomas, using the Series B Gamma-Knife, between 1999 and 2005. The iso-center number varied between 2 and 13, and the overall treatment time from 25.4–129.58 min. The prescription doses varied from 10–14 Gy. To obtain physical dose and dose-rates from each iso-center, in a number of locations in the region of interest, a prototype version of the Leksell GammaPlan® was used. For an individual patient, BED values varied by up to 15% for a given physical iso-dose. This was due to variation in the dose prescription at different locations on that iso-dose. Between patients there was a decline in the range of BED values as the overall treatment time increased. This increased treatment time was partly a function of the slow decline in the activity of the sources with time but predominantly due to changes in the number of iso-centers used. Thus, variations in BED values did not correlate with prescription dose but was modified by the overall treatment time. PMID:29296371

  18. Evaluation of stability of stereotactic space defined by cone-beam CT for the Leksell Gamma Knife Icon.

    PubMed

    AlDahlawi, Ismail; Prasad, Dheerendra; Podgorsak, Matthew B

    2017-05-01

    The Gamma Knife Icon comes with an integrated cone-beam CT (CBCT) for image-guided stereotactic treatment deliveries. The CBCT can be used for defining the Leksell stereotactic space using imaging without the need for the traditional invasive frame system, and this allows also for frameless thermoplastic mask stereotactic treatments (single or fractionated) with the Gamma Knife unit. In this study, we used an in-house built marker tool to evaluate the stability of the CBCT-based stereotactic space and its agreement with the standard frame-based stereotactic space. We imaged the tool with a CT indicator box using our CT-simulator at the beginning, middle, and end of the study period (6 weeks) for determining the frame-based stereotactic space. The tool was also scanned with the Icon's CBCT on a daily basis throughout the study period, and the CBCT images were used for determining the CBCT-based stereotactic space. The coordinates of each marker were determined in each CT and CBCT scan using the Leksell GammaPlan treatment planning software. The magnitudes of vector difference between the means of each marker in frame-based and CBCT-based stereotactic space ranged from 0.21 to 0.33 mm, indicating good agreement of CBCT-based and frame-based stereotactic space definition. Scanning 4-month later showed good prolonged stability of the CBCT-based stereotactic space definition. © 2017 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  19. Long-term safety and efficacy of Gamma Knife surgery in classical trigeminal neuralgia: a 497-patient historical cohort study.

    PubMed

    Régis, Jean; Tuleasca, Constantin; Resseguier, Noémie; Carron, Romain; Donnet, Anne; Gaudart, Jean; Levivier, Marc

    2016-04-01

    Gamma Knife surgery (GKS) is one of the surgical alternatives for the treatment of drug-resistant trigeminal neuralgia (TN). This study aims to evaluate the safety and efficacy of GKS in a large population of patients with TN with very long-term clinical follow-up. Between July 1992 and November 2010, 737 patients presenting with TN were treated using GKS. Data were collected prospectively and were further retrospectively evaluated at Timone University Hospital. The frequency and severity of pain, as well as trigeminal nerve function, were evaluated before GKS and regularly thereafter. Radiosurgery using the Gamma Knife (model B, C, 4C, or Perfexion) was performed with the help of both MR and CT targeting. A single 4-mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.6 mm (range 4-14 mm) anterior to the emergence of the nerve (retrogasserian target). A median maximum dose of 85 Gy (range 70-90 Gy) was prescribed. The safety and efficacy are reported for 497 patients with medically refractory classical TN who were never previously treated by GKS and had a follow-up of at least 1 year. The median age in this series was 68.3 years (range 28.1-93.2 years). The median follow-up period was 43.8 months (range 12-174.4 months). Overall, 456 patients (91.75%) were initially pain free in a median time of 10 days (range 1-180 days). Their actuarial probabilities of remaining pain free without medication at 3, 5, 7, and 10 years were 71.8%, 64.9%, 59.7%, and 45.3%, respectively. One hundred fifty-seven patients (34.4%) who were initially pain free experienced at least 1 recurrence, with a median delay of onset of 24 months (range 0.6-150.1 months). However, the actuarial rate of maintaining pain relief without further surgery was 67.8% at 10 years. The hypesthesia actuarial rate at 5 years was 20.4% and at 7 years reached 21.1%, but remained stable until 14 years with a median delay of onset of 12 months (range 1-65 months

  20. Safety and efficacy of endovascular therapy and gamma knife surgery for brain arteriovenous malformations in China: Study protocol for an observational clinical trial.

    PubMed

    Jin, Hengwei; Huo, Xiaochuan; Jiang, Yuhua; Li, Xiaolong; Li, Youxiang

    2017-09-01

    Brain arteriovenous malformations (BAVMs) are associated with high morbidity and mortality. The treatment of BAVM remains controversial. Microinvasive treatment, including endovascular therapy and gamma knife surgery, has been the first choice in many conditions. However, the overall clinical outcome of microinvasive treatment remains unknown and a prospective trial is needed. This is a prospective, non-randomized, and multicenter observational registry clinical trial to evaluate the safety and efficacy of microinvasive treatment for BAVMs. The study will require up to 400 patients in approximately 12 or more centers in China, followed for 2 years. Main subjects of this study are BAVM patients underwent endovascular therapy and/or gamma knife surgery. The trial will not affect the choice of treatment modality. The primary outcomes are perioperative complications (safety), and postoperative hemorrhage incidence rate and complete occlusion rate (efficacy). Secondary outcomes are elimination of hemorrhage risk factors (coexisting aneurysms and arteriovenous fistula), volume reduction and remission of symptoms. Safety and efficacy of endovascular therapy, gamma knife surgery, and various combination modes of the two modalities will be compared. Operative complications and outcomes at pretreatment, post-treatment, at discharge and at 3 months, 6 months and 2 years follow-up intervals will be analyzed using the modified Rankin Scale (mRS). The most confusion on BAVM treatment is whether to choose interventional therapy or medical therapy, and the choice of interventional therapy modes. This study will provide evidence for evaluating the safety and efficacy of microinvasive treatment in China, to characterize the microinvasive treatment strategy for BAVMs.

  1. Repeat Radiosurgery for Trigeminal Neuralgia.

    PubMed

    Helis, Corbin A; Lucas, John T; Bourland, J Daniel; Chan, Michael D; Tatter, Stephen B; Laxton, Adrian W

    2015-11-01

    Repeat Gamma Knife radiosurgery (GKRS) is an established option for patients whose pain has recurred after the initial procedure, with reported success rates varying from 68% to 95%. Predictive factors for response to the repeat GKRS are ill-defined. This cohort study aimed to report the outcomes and factors predictive of success for patients who have undergone repeated GKRS for trigeminal neuralgia at Wake Forest University Baptist Medical Center. Between 1999 and 2013, 152 patients underwent repeat GKRS at Wake Forest, 125 of whom were available for long-term follow-up. A retrospective chart review and telephone interviews were conducted to determine background medical history, dosimetric data, outcomes, and adverse effects of the procedure. Eighty-four percent of patients achieved at least Barrow Neurological Institute (BNI) IIIb pain relief, with 46% achieving BNI I. The 1-, 3-, and 5-year rates of BNI I pain relief were 63%, 50%, and 37%, respectively. The 1-, 3-, and 5-year rates of BNI IIIb or better pain relief were 74%, 59%, and 46%, respectively. One patient experienced bothersome numbness and 2 patients developed anesthesia dolorosa. The dominant predictive factors for pain relief were facial numbness after the first GKRS and a positive pain response to the first GKRS. Repeat GKRS is an effective method of treating recurrent trigeminal neuralgia. Patients who have facial numbness after the first treatment and a positive pain response to the first GKRS are significantly more likely to respond well to the second treatment.

  2. Stereotactic radiosurgery for trigeminal neuralgia utilizing the BrainLAB Novalis system.

    PubMed

    Zahra, Hadi; Teh, Bin S; Paulino, Arnold C; Yoshor, Daniel; Trask, Todd; Baskin, David; Butler, E Brian

    2009-12-01

    Stereotactic radiosurgery (SRS) is one of the least invasive treatments for trigeminal neuralgia (TN). To date, most reports have been about Cobalt-based treatments (i.e., Gamma Knife) with limited data on image-guided stereotactic linear accelerator treatments. We describe our initial experience of using BrainLAB Novalis stereotactic system for the radiosurgical treatment of TN. A total of 20 patients were treated between July 2004 and February 2007. Each SRS procedure was performed using the BrainLAB Novalis System. Thin cuts MRI images of 1.5 mm thickness were acquired and fused with the simulation CT of each patient. Majority of the patients received a maximum dose of 90 Gy. The median brainstem dose to 1.0 cc and 0.1 cc was 2.3 Gy and 13.5 Gy, respectively. In addition, specially acquired three-dimensional fast imaging sequence employing steady-state acquisition (FIESTA) MRI was utilized to improve target delineation of the trigeminal proximal nerve root entry zone. Barrow Neurological Index (BNI) pain scale for TN was used for assessing treatment outcome. At a median follow-up time of 14.2 months, 19 patients (95%) reported at least some improvement in pain. Eight (40%) patients were completely pain-free and stopped all medications (BNI Grade I) while another 2 (10%) patients also stopped medications but reported occasional pain (BNI Grade II). Another 2 (10%) patients reported no pain and 7 (35%) patients only occasional pain while continuing medications, BNI Grade IIIA and IIIB, respectively. Median time to pain control was 8.5 days (range: 1-70 days). No patient reported severe pain, worsening pain or any pain not controlled on their previously taken medication. Intermittent or persistent facial numbness following treatments occurred in 35% of patients. No other complications were reported. Stereotactic radiosurgery using the BrainLAB Novalis system is a safe and effective treatment for TN. This information is important as more centers are obtaining image

  3. Dose fractionated gamma knife radiosurgery for large arteriovenous malformations on daily or alternate day schedule outside the linear quadratic model: Proof of concept and early results. A substitute to volume fractionation.

    PubMed

    Mukherjee, Kanchan Kumar; Kumar, Narendra; Tripathi, Manjul; Oinam, Arun S; Ahuja, Chirag K; Dhandapani, Sivashanmugam; Kapoor, Rakesh; Ghoshal, Sushmita; Kaur, Rupinder; Bhatt, Sandeep

    2017-01-01

    To evaluate the feasibility, safety and efficacy of dose fractionated gamma knife radiosurgery (DFGKRS) on a daily schedule beyond the linear quadratic (LQ) model, for large volume arteriovenous malformations (AVMs). Between 2012-16, 14 patients of large AVMs (median volume 26.5 cc) unsuitable for surgery or embolization were treated in 2-3 of DFGKRS sessions. The Leksell G frame was kept in situ during the whole procedure. 86% (n = 12) patients had radiologic evidence of bleed, and 43% (n = 6) had presented with a history of seizures. 57% (n = 8) patients received a daily treatment for 3 days and 43% (n = 6) were on an alternate day (2 fractions) regimen. The marginal dose was split into 2 or 3 fractions of the ideal prescription dose of a single fraction of 23-25 Gy. The median follow up period was 35.6 months (8-57 months). In the three-fraction scheme, the marginal dose ranged from 8.9-11.5 Gy, while in the two-fraction scheme, the marginal dose ranged from 11.3-15 Gy at 50% per fraction. Headache (43%, n = 6) was the most common early postoperative complication, which was controlled with short course steroids. Follow up evaluation of at least three years was achieved in seven patients, who have shown complete nidus obliteration in 43% patients while the obliteration has been in the range of 50-99% in rest of the patients. Overall, there was a 67.8% reduction in the AVM volume at 3 years. Nidus obliteration at 3 years showed a significant rank order correlation with the cumulative prescription dose (p 0.95, P value 0.01), with attainment of near-total (more than 95%) obliteration rates beyond 29 Gy of the cumulative prescription dose. No patient receiving a cumulative prescription dose of less than 31 Gy had any severe adverse reaction. In co-variate adjusted ordinal regression, only the cumulative prescription dose had a significant correlation with common terminology criteria for adverse events (CTCAE) severity (P value 0.04), independent of age, AVM volume

  4. Quality assurance for gamma knives

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, E.D.; Banks, W.W.; Fischer, L.E.

    1995-09-01

    This report describes and summarizes the results of a quality assurance (QA) study of the Gamma Knife, a nuclear medical device used for the gamma irradiation of intracranial lesions. Focus was on the physical aspects of QA and did not address issues that are essentially medical, such as patient selection or prescription of dose. A risk-based QA assessment approach was used. Sample programs for quality control and assurance are included. The use of the Gamma Knife was found to conform to existing standards and guidelines concerning radiation safety and quality control of external beam therapies (shielding, safety reviews, radiation surveys,more » interlock systems, exposure monitoring, good medical physics practices, etc.) and to be compliant with NRC teletherapy regulations. There are, however, current practices for the Gamma Knife not covered by existing, formalized regulations, standards, or guidelines. These practices have been adopted by Gamma Knife users and continue to be developed with further experience. Some of these have appeared in publications or presentations and are slowly finding their way into recommendations of professional organizations.« less

  5. End-to-end test of spatial accuracy in Gamma Knife treatments for trigeminal neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brezovich, Ivan A., E-mail: ibrezovich@uabmc.edu; Wu, Xingen; Duan, Jun

    2014-11-01

    Purpose: Spatial accuracy is most crucial when small targets like the trigeminal nerve are treated. Although current quality assurance procedures typically verify that individual apparatus, like the MRI scanner, CT scanner, Gamma Knife, etc., are meeting specifications, the cumulative error of all equipment and procedures combined may exceed safe margins. This study uses an end-to-end approach to assess the overall targeting errors that may have occurred in individual patients previously treated for trigeminal neuralgia. Methods: The trigeminal nerve is simulated by a 3 mm long, 3.175 mm (1/8 in.) diameter MRI-contrast filled cavity embedded within a PMMA plastic capsule. Themore » capsule is positioned within the head frame such that the location of the cavity matches the Gamma Knife coordinates of an arbitrarily chosen, previously treated patient. Gafchromic EBT2 film is placed at the center of the cavity in coronal and sagittal orientations. The films are marked with a pinprick to identify the cavity center. Treatments are planned for radiation delivery with 4 mm collimators according to MRI and CT scans using the clinical localizer boxes and acquisition protocols. Shots are planned so that the 50% isodose surface encompasses the cavity. Following irradiation, the films are scanned and analyzed. Targeting errors are defined as the distance between the pinprick, which represents the intended target, and the centroid of the 50% isodose line, which is the center of the radiation field that was actually delivered. Results: Averaged over ten patient simulations, targeting errors along the x, y, and z coordinates (patient’s left-to-right, posterior-to-anterior, and head-to-foot) were, respectively, −0.060 ± 0.363, −0.350 ± 0.253, and 0.348 ± 0.204 mm when MRI was used for treatment planning. Planning according to CT exhibited generally smaller errors, namely, 0.109 ± 0.167, −0.191 ± 0.144, and 0.211 ± 0.094 mm. The largest errors along individual axes

  6. Tumour regression of uveal melanoma after ruthenium-106 brachytherapy or stereotactic radiotherapy with gamma knife or linear accelerator.

    PubMed

    Georgopoulos, Michael; Zehetmayer, Martin; Ruhswurm, Irene; Toma-Bstaendig, Sabine; Ségur-Eltz, Nikolaus; Sacu, Stefan; Menapace, Rupert

    2003-01-01

    This study assesses differences in relative tumour regression and internal acoustic reflectivity after 3 methods of radiotherapy for uveal melanoma: (1) brachytherapy with ruthenium-106 radioactive plaques (RU), (2) fractionated high-dose gamma knife stereotactic irradiation in 2-3 fractions (GK) or (3) fractionated linear-accelerator-based stereotactic teletherapy in 5 fractions (Linac). Ultrasound measurements of tumour thickness and internal reflectivity were performed with standardised A scan pre-operatively and 3, 6, 9, 12, 18, 24 and 36 months postoperatively. Of 211 patients included in the study, 111 had a complete 3-year follow-up (RU: 41, GK: 37, Linac: 33). Differences in tumour thickness and internal reflectivity were assessed with analysis of variance, and post hoc multiple comparisons were calculated with Tukey's honestly significant difference test. Local tumour control was excellent with all 3 methods (>93%). At 36 months, relative tumour height reduction was 69, 50 and 30% after RU, GK and Linac, respectively. In all 3 treatment groups, internal reflectivity increased from about 30% initially to 60-70% 3 years after treatment. Brachytherapy with ruthenium-106 plaques results in a faster tumour regression as compared to teletherapy with gamma knife or Linac. Internal reflectivity increases comparably in all 3 groups. Besides tumour growth arrest, increasing internal reflectivity is considered as an important factor indicating successful treatment. Copyright 2003 S. Karger AG, Basel

  7. Optimal Treatment Decision for Brain Metastases of Unknown Primary Origin: The Role and Timing of Radiosurgery

    PubMed Central

    Han, Hyun Jin; Chang, Won Seok; Jung, Hyun Ho; Park, Yong Gou

    2016-01-01

    Background Up to 15% of all patients with brain metastases have no clearly detected primary site despite intensive evaluation, and this incidence has decreased with the use of improved imaging technology. Radiosurgery has been evaluated as one of the treatment modality for patients with limited brain metastases. In this study, we evaluated the effectiveness of radiosurgery for brain metastases from unknown primary tumors. Methods We retrospectively evaluated 540 patients who underwent gamma knife radiosurgery (GKRS) for brain metastases radiologically diagnosed between August 1992 and September 2007 in our institution. First, the brain metastases were grouped into metachronous, synchronous, and precocious presentations according to the timing of diagnosis of the brain metastases. Then, synchronous and precocious brain metastases were further grouped into 1) unknown primary; 2) delayed known primary; and 3) synchronous metastases according to the timing of diagnosis of the primary origin. We analyzed the survival time and time to new brain metastasis in each group. Results Of the 540 patients, 29 (5.4%) presented precocious or synchronous metastases (34 GKRS procedures for 174 lesions). The primary tumor was not found even after intensive and repeated systemic evaluation in 10 patients (unknown primary, 34.5%); found after 8 months in 3 patients (delayed known primary, 1.2%); and diagnosed at the same time as the brain metastases in 16 patients (synchronous metastasis, 55.2%). No statistically significant differences in survival time and time to new brain metastasis were found among the three groups. Conclusion Identification of a primary tumor before GKRS did not affect the patient outcomes. If other possible differential diagnoses were completely excluded, early GKRS can be an effective treatment option for brain metastases from unknown primary tumor. PMID:27867920

  8. Gammaknife radiosurgery in patients with acromegaly.

    PubMed

    Erdur, Fatih M; Kilic, Türker; Peker, Selcuk; Celik, Ozlem; Kadioglu, Pinar

    2011-12-01

    We aimed to evaluate the efficacy and reliability of gamma-knife radiosurgery (GKR) in 22 patients with acromegaly at the Endocrinology-Metabolism Clinic of Cerrahpasa Medical School. We collected data retrospectively from hospital records on disease activity and other pituitary functions, pituitary MRI and visual fields, before GKR and 6, 12, 24, 36, 48 and 60 months after GKR. The median follow-up duration after GKR was 60 months (interquartile range [IQR]: 24-60 months). The remission rate was 54.5% after the 60 months of follow-up. The median growth hormone (GH) level at 60 months after GKR (0.99 ng/mL [IQR: 0.36-2.2]) was significantly lower than the median GH level before GKR (5.65 ng/mL [IQR: 3.85-7.2] (p=0.002). The median insulin-like growth factor-1 (IGF-1) level 60 months after GKR (221.5 ng/mL [IQR: 149-535]) was significantly lower than the median IGF-1 level before GKR (582.5 ng/mL [IQR: 515-655]) (p=0.008). Tumour growth was well controlled in 20 patients (95.2%). Six patients (28.6%) developed new-onset hypopituitarism. We concluded that GKR is an effective adjuvant treatment to control tumour growth, lower GH and IGF-1 levels, and to increase remission rates in patients with acromegaly who were refractory to surgical and medical treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Stereotactic radiosurgery for the treatment of symptomatic brainstem cavernous malformations.

    PubMed

    Monaco, Edward A; Khan, Aftab A; Niranjan, Ajay; Kano, Hideyuki; Grandhi, Ramesh; Kondziolka, Douglas; Flickinger, John C; Lunsford, L Dade

    2010-09-01

    The authors performed a retrospective review of prospectively collected data to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) for the treatment of patients harboring symptomatic solitary cavernous malformations (CMs) of the brainstem that bleed repeatedly and are high risk for resection. Between 1988 and 2005, 68 patients (34 males and 34 females) with solitary, symptomatic CMs of the brainstem underwent Gamma Knife surgery. The mean patient age was 41.2 years, and all patients had suffered at least 2 symptomatic hemorrhages (range 2-12 events) before radiosurgery. Prior to SRS, 15 patients (22.1%) had undergone attempted resection. The mean volume of the malformation treated was 1.19 ml, and the mean prescribed marginal radiation dose was 16 Gy. The mean follow-up period was 5.2 years (range 0.6-12.4 years). The pre-SRS annual hemorrhage rate was 32.38%, or 125 hemorrhages, excluding the first hemorrhage, over a total of 386 patient-years. Following SRS, 11 hemorrhages were observed within the first 2 years of follow-up (8.22% annual hemorrhage rate) and 3 hemorrhages were observed in the period after the first 2 years of follow-up (1.37% annual hemorrhage rate). A significant reduction (p < 0.0001) in the risk of brainstem CM hemorrhages was observed following radiosurgical treatment, as well as in latency period of 2 years after SRS (p < 0.0447). Eight patients (11.8%) experienced new neurological deficits as a result of adverse radiation effects following SRS. The results of this study support a role for the use of SRS for symptomatic CMs of the brainstem, as it is relatively safe and appears to reduce rebleeding rates in this high-surgical-risk location.

  10. Radiosurgery for symptomatic cavernous malformations: A multi-institutional retrospective study in Japan

    PubMed Central

    Kida, Yoshihisa; Hasegawa, Toshinori; Iwai, Yoshiyasu; Shuto, Takashi; Satoh, Manabu; Kondoh, Takeshi; Hayashi, Motohiro

    2015-01-01

    Background: A group study for symptomatic cavernous malformation (CM) treated with gamma knife (GK) surgery was performed. Methods: A total of 298 cases collected from 23 GK centers across Japan were included. Hemorrhage was the most common manifestation, followed by seizures and neurological deficits. Most of the lesions were located in the brainstem and basal ganglia, followed by the cerebral or cerebellar hemispheres. The CMs, which had a mean diameter of 14.8 mm, were treated using GK surgery with a mean marginal dose of 14.6 Gy. Results: In terms of hemorrhage-free survival (HFS), a marked dissociation was confirmed between the hemorrhage and seizure groups, while no obvious difference was noted between sexes. Superficial CMs located in cerebellum or lobar regions responded to the treatment better than deeply located CMs in the basal ganglia or brainstem. No significant difference of dose-dependent response was seen for three different ranges of marginal dose: Less than 15 Gy, between 15 and 20 Gy, and more than 20 Gy. Complications were more frequent after a marginal dose of over 15 Gy and in patients with lesions more than 15 mm in diameter. The rates of annual hemorrhage were estimated to be 7.4% during the first 2 years after radiosurgery and 2.8% thereafter. The overall hemorrhage rate after radiosurgery was 4.4%/year/patient. Conclusion: The risk of hemorrhage is considerably reduced after GK treatment. The HFS as well as annual hemorrhage rate after GK treatment was apparently superior to that after conservative treatment for symptomatic CMs. To optimize the success of GK treatment, it is important to reduce the incidence of complications. PMID:26005588

  11. Stereotactic radiosurgery for trigeminal neuralgia: a systematic review.

    PubMed

    Tuleasca, Constantin; Régis, Jean; Sahgal, Arjun; De Salles, Antonio; Hayashi, Motohiro; Ma, Lijun; Martínez-Álvarez, Roberto; Paddick, Ian; Ryu, Samuel; Slotman, Ben J; Levivier, Marc

    2018-04-27

    OBJECTIVES The aims of this systematic review are to provide an objective summary of the published literature specific to the treatment of classical trigeminal neuralgia with stereotactic radiosurgery (RS) and to develop consensus guideline recommendations for the use of RS, as endorsed by the International Society of Stereotactic Radiosurgery (ISRS). METHODS The authors performed a systematic review of the English-language literature from 1951 up to December 2015 using the Embase, PubMed, and MEDLINE databases. The following MeSH terms were used in a title and abstract screening: "radiosurgery" AND "trigeminal." Of the 585 initial results obtained, the authors performed a full text screening of 185 studies and ultimately found 65 eligible studies. Guideline recommendations were based on level of evidence and level of consensus, the latter predefined as at least 85% agreement among the ISRS guideline committee members. RESULTS The results for 65 studies (6461 patients) are reported: 45 Gamma Knife RS (GKS) studies (5687 patients [88%]), 11 linear accelerator (LINAC) RS studies (511 patients [8%]), and 9 CyberKnife RS (CKR) studies (263 patients [4%]). With the exception of one prospective study, all studies were retrospective. The mean maximal doses were 71.1-90.1 Gy (prescribed at the 100% isodose line) for GKS, 83.3 Gy for LINAC, and 64.3-80.5 Gy for CKR (the latter two prescribed at the 80% or 90% isodose lines, respectively). The ranges of maximal doses were as follows: 60-97 Gy for GKS, 50-90 Gy for LINAC, and 66-90 Gy for CKR. Actuarial initial freedom from pain (FFP) without medication ranged from 28.6% to 100% (mean 53.1%, median 52.1%) for GKS, from 17.3% to 76% (mean 49.3%, median 43.2%) for LINAC, and from 40% to 72% (mean 56.3%, median 58%) for CKR. Specific to hypesthesia, the crude rates (all Barrow Neurological Institute Pain Intensity Scale scores included) ranged from 0% to 68.8% (mean 21.7%, median 19%) for GKS, from 11.4% to 49.7% (mean 27

  12. Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yip, Ho Yin, E-mail: hoyinyip@yahoo.com.hk; Mui, Wing Lun A.; Lee, Joseph W.Y.

    2013-07-01

    Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systemsmore » was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time.« less

  13. Long-term effectiveness and safety of stereotactic gamma knife surgery as a primary sole treatment in the management of glomus jagulare tumor.

    PubMed

    Hafez, Raef F A; Morgan, Magad S; Fahmy, Osama M; Hassan, Hamdy T

    2018-05-01

    This study aims to report and confirm long-term effectiveness and safety of stereotactic Gamma Knife Surgery as a primary sole treatment in the management of 40 glomus jagulare tumors patients. Retrospective analysis of clinical and radiological outcomes of 40 GJTs consecutive patients treated with GKS as primary sole treatment at International Medical Center (IMC), Cairo-Egypt from the beginning of 2005 till the end of 2014,with mean follow-up period of 84 months (range 36-156 months), mean tumor volume was 6.5 cc, and mean peripheral radiation dose of 15 Gy, to mean isodose curve of 38%. The most common neurological deficit at initial evaluation was bulbar symptoms in 24 patients, followed by pulsatile tinnitus in 22, deterioration of hearing in 20 patients. The overall clinical control achieved in 92.5% of patients, while actuarial tumor size control rate post- GKS was 97.5% at 3 years, 97% at 5 years and 92% at 10 years of follow-up period. Gamma knife surgery could be used effectively and safely as a primary sole treatment tool in the management of glomus jugulare tumors. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Peritumoral Brain Edema after Stereotactic Radiosurgery for Asymptomatic Intracranial Meningiomas: Risks and Pattern of Evolution.

    PubMed

    Hoe, Yeon; Choi, Young Jae; Kim, Jeong Hoon; Kwon, Do Hoon; Kim, Chang Jin; Cho, Young Hyun

    2015-10-01

    To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas. A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression. Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (p<0.001), hemispheric tumor location (p=0.005), and pre-treatment PTE (p<0.001) were associated with an increased risk of PTE. rEI reached its maximum value at 11 months after SRS and decreased thereafter, and symptoms resolved within 24 months in most patients (85.7%). Caution should be exercised in decision-making on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.

  15. Repeat Gamma Knife surgery for vestibular schwannomas

    PubMed Central

    Lonneville, Sarah; Delbrouck, Carine; Renier, Cécile; Devriendt, Daniel; Massager, Nicolas

    2015-01-01

    Background: Gamma Knife (GK) surgery is a recognized treatment option for the management of small to medium-sized vestibular schwannoma (VS) associated with high-tumor control and low morbidity. When a radiosurgical treatment fails to stop tumor growth, repeat GK surgery can be proposed in selected cases. Methods: A series of 27 GK retreatments was performed in 25 patients with VS; 2 patients underwent three procedures. The median time interval between GK treatments was 45 months. The median margin dose used for the first, second, and third GK treatments was 12 Gy, 12 Gy, and 14 Gy, respectively. Six patients (4 patients for the second irradiation and 2 patients for the third irradiation) with partial tumor regrowth were treated only on the growing part of the tumor using a median margin dose of 13 Gy. The median tumor volume was 0.9, 2.3, and 0.7 cc for the first, second, and third treatments, respectively. Stereotactic positron emission tomography (PET) guidance was used for dose planning in 6 cases. Results: Mean follow-up duration was 46 months (range 24–110). At the last follow-up, 85% of schwannomas were controlled. The tumor volume decreased, remained unchanged, or increased after retreatment in 15, 8, and 4 cases, respectively. Four patients had PET during follow-up, and all showed a significant metabolic decrease of the tumor. Hearing was not preserved after retreatment in any patients. New facial or trigeminal palsy did not occur after retreatment. Conclusions: Our results support the long-term efficacy and low morbidity of repeat GK treatment for selected patients with tumor growth after initial treatment. PMID:26500799

  16. International multicenter cohort study of pediatric brain arteriovenous malformations. Part 2: Outcomes after stereotactic radiosurgery.

    PubMed

    Starke, Robert M; Ding, Dale; Kano, Hideyuki; Mathieu, David; Huang, Paul P; Feliciano, Caleb; Rodriguez-Mercado, Rafael; Almodovar, Luis; Grills, Inga S; Silva, Danilo; Abbassy, Mahmoud; Missios, Symeon; Kondziolka, Douglas; Barnett, Gene H; Dade Lunsford, L; Sheehan, Jason P

    2017-02-01

    OBJECTIVE Pediatric patients (age < 18 years) harboring brain arteriovenous malformations (AVMs) are burdened with a considerably higher cumulative lifetime risk of hemorrhage than adults. Additionally, the pediatric population was excluded from recent prospective comparisons of intervention versus conservative management for unruptured AVMs. The aims of this multicenter, retrospective cohort study are to analyze the outcomes after stereotactic radiosurgery for unruptured and ruptured pediatric AVMs. METHODS We analyzed and pooled AVM radiosurgery data from 7 participating in the International Gamma Knife Research Foundation. Patients younger than 18 years of age who had at least 12 months of follow-up were included in the study cohort. Favorable outcome was defined as AVM obliteration, no post-radiosurgical hemorrhage, and no permanently symptomatic radiation-induced changes (RIC). The post-radiosurgery outcomes of unruptured versus ruptured pediatric AVMs were compared, and statistical analyses were performed to identify predictive factors. RESULTS The overall pediatric AVM cohort comprised 357 patients with a mean age of 12.6 years (range 2.8-17.9 years). AVMs were previously treated with embolization, resection, and fractionated external beam radiation therapy in 22%, 6%, and 13% of patients, respectively. The mean nidus volume was 3.5 cm 3 , 77% of AVMs were located in eloquent brain areas, and the Spetzler-Martin grade was III or higher in 59%. The mean radiosurgical margin dose was 21 Gy (range 5-35 Gy), and the mean follow-up was 92 months (range 12-266 months). AVM obliteration was achieved in 63%. During a cumulative latency period of 2748 years, the annual post-radiosurgery hemorrhage rate was 1.4%. Symptomatic and permanent radiation-induced changes occurred in 8% and 3%, respectively. Favorable outcome was achieved in 59%. In the multivariate logistic regression analysis, the absence of prior AVM embolization (p = 0.001) and higher margin dose (p < 0

  17. Long-term follow-up studies of Gamma Knife surgery for patients with neurofibromatosis Type 2.

    PubMed

    Sun, Shibin; Liu, Ali

    2014-12-01

    The aim of this study was to evaluate long-term clinical outcomes after Gamma Knife surgery (GKS) for patients with neurofibromatosis Type 2 (NF2) and the role of GKS in the management of NF2. From December 1994 through December 2008, a total of 46 patients (21 male, 25 female) with NF2 underwent GKS and follow-up evaluation for at least 5 years at the Gamma Knife Center of the Beijing Neurosurgical Institute. GKS was performed using the Leksell Gamma Knife Models B and C. The mean age of the patients was 30 years (range 13-59 years). A family history of NF2 was found for 9 (20%) patients. The NF2 phenotype was thought to be Wishart for 20 (44%) and Feiling-Gardner for 26 (56%) patients. Among these 46 patients, GKS was performed to treat 195 tumors (73 vestibular schwannomas and 122 other tumors including other schwannomas and meningiomas). For vestibular schwannomas, the mean volume was 5.1 cm(3) (median 3.6 cm(3), range 0.3-27.3 cm(3)), the mean margin dose was 12.9 Gy (range 10-14 Gy), and the mean maximum dose was 27.3 Gy (range 16.2-40 Gy). For other tumors, the mean volume was 1.7 cm(3) (range 0.3-5.5 cm(3)), the mean margin dose was 13.3 Gy (range 11-14 Gy), and the mean maximum dose was 26.0 Gy (range 18.0-30.4 Gy). The median duration of follow-up was 109 months (range 8-195 months). For the 73 vestibular schwannomas that underwent GKS, the latest follow-up MR images demonstrated regression of 30 (41%) tumors, stable size for 31 (43%) tumors, and enlargement of 12 (16%) tumors. The total rate of tumor control for bilateral vestibular schwannomas in patients with NF2 was 84%. Of the 122 other types of tumors that underwent GKS, 103 (85%) showed no tumor enlargement. The rate of serviceable hearing preservation after GKS was 31.9% (15/47). The actuarial rates for hearing preservation at 3 years, 5 years, 10 years, and 15 years were 98%, 93%, 44%, and 17%, respectively. Of the 46 patients, 22 (48%) became completely bilaterally deaf, 17 (37%) retained

  18. Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cusumano, Davide, E-mail: davide.cusumano@unimi.it; Fumagalli, Maria L.; Marchetti, Marcello

    2015-10-01

    Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses usingmore » this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk.« less

  19. Atlas-based functional radiosurgery: Early results

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stancanello, J.; Romanelli, P.; Pantelis, E.

    2009-02-15

    Functional disorders of the brain, such as dystonia and neuropathic pain, may respond poorly to medical therapy. Deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and the centromedian nucleus of the thalamus (CMN) may alleviate dystonia and neuropathic pain, respectively. A noninvasive alternative to DBS is radiosurgical ablation [internal pallidotomy (IP) and medial thalamotomy (MT)]. The main technical limitation of radiosurgery is that targets are selected only on the basis of MRI anatomy, without electrophysiological confirmation. This means that, to be feasible, image-based targeting must be highly accurate and reproducible. Here, we report on the feasibility ofmore » an atlas-based approach to targeting for functional radiosurgery. In this method, masks of the GPi, CMN, and medio-dorsal nucleus were nonrigidly registered to patients' T1-weighted MRI (T1w-MRI) and superimposed on patients' T2-weighted MRI (T2w-MRI). Radiosurgical targets were identified on the T2w-MRI registered to the planning CT by an expert functional neurosurgeon. To assess its feasibility, two patients were treated with the CyberKnife using this method of targeting; a patient with dystonia received an IP (120 Gy prescribed to the 65% isodose) and a patient with neuropathic pain received a MT (120 Gy to the 77% isodose). Six months after treatment, T2w-MRIs and contrast-enhanced T1w-MRIs showed edematous regions around the lesions; target placements were reevaluated by DW-MRIs. At 12 months post-treatment steroids for radiation-induced edema and medications for dystonia and neuropathic pain were suppressed. Both patients experienced significant relief from pain and dystonia-related problems. Fifteen months after treatment edema had disappeared. Thus, this work shows promising feasibility of atlas-based functional radiosurgery to improve patient condition. Further investigations are indicated for optimizing treatment dose.« less

  20. TH-A-BRC-00: New Task Groups for External Beam QA: An Overview

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    2016-06-15

    AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance -more » Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and

  1. TH-A-BRC-03: AAPM TG218: Measurement Methods and Tolerance Levels for Patient-Specific IMRT Verification QA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miften, M.

    2016-06-15

    AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance -more » Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and

  2. Frameless Stereotactic Radiosurgery for Treatment of Multiple Sclerosis-Related Trigeminal Neuralgia.

    PubMed

    Conti, Alfredo; Pontoriero, Antonio; Iatì, Giuseppe; Esposito, Felice; Siniscalchi, Enrico Nastro; Crimi, Salvatore; Vinci, Sergio; Brogna, Anna; De Ponte, Francesco; Germanò, Antonino; Pergolizzi, Stefano; Tomasello, Francesco

    2017-07-01

    Trigeminal neuralgia (TN) affects 7% of patients with multiple sclerosis (MS). In such patients, TN is difficult to manage either pharmacologically and surgically. Radiosurgical rhizotomy is an effective treatment option. The nonisocentric geometry of radiation beams of CyberKnife introduces new concepts in the treatment of TN. Its efficacy for MS-related TN has not yet been demonstrated. Twenty-seven patients with refractory TN and MS were treated. A nonisocentric beams distribution was chosen; the maximal target dose was 72.5 Gy. The maximal dose to the brainstem was <12 Gy. Effects on pain, medications, sensory disturbance, rate, and time of pain recurrence were analyzed. Median follow-up was 37 (18-72) months. Barrow Neurological Institute pain scale score I-III was achieved in 23/27 patients (85%) within 45 days. Prescription isodose line (80%) accounting for a dose of 58 Gy incorporated an average of 4.85 mm (4-6 mm) of the nerve and mean nerve volume of 26.4 mm 3 (range 20-38 mm 3 ). Seven out of 27 patients (26%) had mild, not bothersome, facial numbness (Barrow Neurological Institute numbness score II). The rate of pain control decreased progressively after the first year, and only 44% of patients retained pain control 4 years later. Frameless radiosurgery can be effectively used to perform retrogasserian rhizotomy. Pain relief was satisfactory and, with our dose/volume constraints, no sensory complications were recorded. Nonetheless, long-term pain control was possible in less than half of the patients. This is a limitation that CyberKnife radiosurgery shares with other techniques in MS patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Clinical Positioning Accuracy for Multisession Stereotactic Radiotherapy With the Gamma Knife Perfexion

    PubMed Central

    Young, Lori A.; Phillips, Mark H.; Cheung, Michael; Halasz, Lia M.; Rockhill, Jason K.

    2017-01-01

    Multisession stereotactic radiation therapy is increasingly being seen as a preferred option for intracranial diseases in close proximity to critical structures and for larger target volumes. The objective of this study is to investigate the reproducibility of the Extend system from Elekta. A retrospective review was conducted for all patients treated with multisession Gamma Knife between July 2010 and June 2015, including both malignant and benign lesions. Eighty-four patients were treated in this 5-year span. The average residual daily setup uncertainty was 0.48 (0.19) mm. We compare measurements of setup uncertainty from the Extend system to measurements performed with a linac-based approach previously used in our center. The Extend system has significantly reduced setup uncertainty for fractionated intracranial treatments at our institution. Positive results were observed in a small population of edentulous patients. The Extend system compares favorably with other approaches to delivering intracranial stereotactic radiotherapy and is a robust, simple-to-use, and precise method for treating multisession intracranial lesions. PMID:28514899

  4. Hypopituitarism after stereotactic radiosurgery for pituitary adenomas.

    PubMed

    Xu, Zhiyuan; Lee Vance, Mary; Schlesinger, David; Sheehan, Jason P

    2013-04-01

    Studies of new-onset Gamma Knife stereotactic radiosurgery (SRS)-induced hypopituitarism in large cohort of pituitary adenoma patients with long-term follow-up are lacking. We investigated the outcomes of SRS for pituitary adenoma patients with regard to newly developed hypopituitarism. This was a retrospective review of patients treated with SRS at the University of Virginia between 1994 and 2006. A total of 262 patients with a pituitary adenoma treated with SRS were reviewed. Thorough endocrine assessment was performed immediately before SRS and in regular follow-ups. Assessment consisted of 24-hour urine free cortisol (patients with Cushing disease), serum adrenocorticotropic hormone, cortisol, follicle-stimulating hormone, luteinizing hormone, insulin-like growth factor-1, growth hormone, testosterone (men), prolactin, thyroid-stimulating hormone, and free T(4). Endocrine remission occurred in 144 of 199 patients with a functioning adenoma. Tumor control rate was 89%. Eighty patients experienced at least 1 axis of new-onset SRS-induced hypopituitarism. The new hypopituitarism rate was 30% based on endocrine follow-up ranging from 6 to 150 months; the actuarial rate of new pituitary hormone deficiency was 31.5% at 5 years after SRS. On univariate and multivariate analyses, variables regarding the increased risk of hypopituitarism included suprasellar extension and higher radiation dose to the tumor margin; there were no correlations among tumor volume, prior transsphenoidal adenomectomy, prior radiation therapy, and age at SRS. SRS provides an effective and safe treatment option for patients with a pituitary adenoma. Higher margin radiation dose to the adenoma and suprasellar extension were 2 independent predictors of SRS-induced hypopituitarism.

  5. [The Effect of Pain Relieving Intervention During Infiltration among Gamma Knife Surgery Patients for Stereotactic Frame Fixation].

    PubMed

    Jang, Young Jun; Kim, Hyeon Ok

    2018-04-01

    This study aimed to compare the effects of three interventions on pain, blood pressure, and pulse rate during infiltration anesthesia in patients about to undergo gamma knife surgeries. The three interventions employed in a university-affiliated Hospital in J City, South Korea were as follows: EMLA cream plus Vapocoolant spray (Vapocoolant, n=30), EMLA cream plus 10.0% Lidocaine spray (Lidocaine, n=30), and EMLA cream only (EMLA, n=30). The equivalent control-group pre test - post test study design was used. Pain was assessed subjectively using the numeric rating scale (NRS) and objectively using a Galvanic Skin Response (GSR) tester. NRS scores were assessed after infiltration anesthesia and the GSR was assessed during infiltration anesthesia. Blood pressure and pulse rate were assessed twice: before and after infiltration anesthesia. Data were collected between August 3, 2016 and March 24, 2017. NRS scores after infiltration anesthesia and the GSR during infiltration anesthesia were significantly lower in the Vapocoolant group than in the Lidocaine and EMLA groups (F=13.56, p<.001 and F=14.43, p<.001, respectively). The increase in systolic blood pressure (F=4.77, p=.011) and in pulse rates (F=4.78, p=.011) before and after infiltration anesthesia were significantly smaller in the Vapocoolant group than in the Lidocaine and EMLA groups; however, no significant differences were observed in diastolic blood pressures (F=1.51, p=.227). EMLA cream plus Vapocoolant spray was the most effective intervention to relieve pain and to lower increase in systolic blood pressure and pulse rate caused by infiltration anesthesia for stereotactic frame fixation. Thus, application of Vapocoolant spray in addition to EMLA cream is highly recommended as a nursing intervention for patients undergoing gamma knife surgeries. © 2018 Korean Society of Nursing Science.

  6. Ingenious laparoscopic knife.

    PubMed

    Goel, Rajiv; Modi, Pranjal

    2007-06-01

    Retroperitoneoscopic ureterolithotomy may be an option in selected group of patients. We present our cost effective, reliable ingenious laparoscopic knife of ureteric incision during retroperitoneoscopic ureterolithotomy. Ingenious laparoscopic knife is made by firmly tying stab knife to 5 mm laparoscopic instrument. This knife is passed through 10-mm renal angle port for making ureteric incision. Ingenious laparoscopic knife has been successfully used in 22 patients with no intraoperative and postoperative complications. Ingenious laparoscopic knife is cost effective, reliable instrument for ureteric incision during retroperitoneoscopic ureterolithotomy.

  7. Clinical features of brain metastases from hepatocellular carcinoma using gamma knife surgery.

    PubMed

    Ogino, Akiyoshi; Hirai, Tatsuo; Serizawa, Toru; Yoshino, Atsuo

    2018-05-01

    Brain metastases from hepatocellular carcinoma (HCC) are rare, but their incidence is increasing because of developments in recent therapeutic advances. The purpose of this study was to investigate the characteristics of brain metastases from HCC, to evaluate the predictive factors, and to assess the efficacy of gamma knife surgery (GKS). A retrospective study was performed on patients with brain metastases from HCC who were treated at Tokyo Gamma Unit Center from 2005 to 2014. Nineteen patients were identified. The median age at diagnosis of brain metastases was 67.0 years. Fifteen patients were male and four patients were female. Six patients were infected with hepatitis B virus (HBV). Two patients were infected with hepatitis C virus (HCV). Eleven patients were not infected with HBV or HCV. The median interval from the diagnosis of HCC to brain metastases was 32.0 months. The median number of brain metastases was two. The median Karnofsky performance score at first GKS was 70. The median survival time following brain metastases was 21.0 weeks. Six-month and 1-year survival rates were 41.2 and 0%, respectively. One month after GKS, no tumor showed progressive disease. The HBV infection (positive vs. negative) was significantly associated with survival according to univariate analysis (p = 0.002). The patients having brain metastases from HCC had poor prognosis and low performance state. Therefore, GKS is an acceptable option for controlling brain metastases from HCC because GKS is noninvasive remedy and local control is reasonable.

  8. Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3.

    PubMed

    Cusumano, Davide; Fumagalli, Maria L; Marchetti, Marcello; Fariselli, Laura; De Martin, Elena

    2015-01-01

    Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses using this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  9. TU-F-CAMPUS-T-03: A Novel Iris Quality Assurance Phantom for the CyberKnife Radiosurgery System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Descovich, M; Pinnaduwage, D; Sudhyadhom, A

    Purpose: A novel CCD camera and conical scintillator based phantom that is capable of measuring the targeting and field size accuracy of a robotic radiosurgery system has been developed. This work investigates its application in measuring the field sizes and beam divergence of the CyberKnife variable aperture collimator (Iris). Methods: The phantom was placed on the treatment couch and the robot position was adjusted to obtain an anterior -posterior beam perpendicular to the cone’s central axis. The FWHM of the 12 Iris apertures (5, 7.5, 10, 12.5, 15, 20, 25, 30, 35, 40, 50, and 60 mm) were measured frommore » the beam flux map on the conical scintillator surface as seen by the CCD camera. For each measurement 30 MU were delivered to the phantom at a dose rate of 1000 MU/min. The measurements were repeated at 4 SAD distances between 75 and 85 cm. These readings were used to project the aperture size as if the flux map on the scintillator were located 80 cm from the source (SSD). These projected FWHM beam diameters were then compared to the commissioning data. Results: A series of 12 beam divergence equations were obtained from the 4 sets of data using linear trend lines on Excel scatter plots. These equations were then used to project the FWHM measurements at 80 cm SSD. The average aperture accuracy for beams from 5 through 40 mm was 0.08 mm. The accuracy for the 50 and 60 mm beams were 0.33 and 0.58 mm when compared to film commissioning data. Conclusion: The experimental results for 10 apertures agree with the stated Iris accuracy of ±0.2 mm at 80 cm SAD. The results for the 50 and 60 mm aperture were repeatable and can serve as a reliable trend indicator of any deviations away from the commissioning values. Brett Nelson is President/CTO of Logos Systems.« less

  10. Role of intracanalicular volumetric and dosimetric parameters on hearing preservation after vestibular schwannoma radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Massager, Nicolas; Nissim, Ouzi; Delbrouck, Carine

    2006-04-01

    Purpose: To analyze the relationship between hearing preservation after gamma knife radiosurgery (GKR) for vestibular schwannoma (VS) and some volumetric and dosimetric parameters of the intracanalicular components of VS. Methods and Materials: This study included 82 patients with a VS treated by GKR; all patients had no NF2 disease, a Gardner-Robertson hearing class 1-4 before treatment, a marginal dose of 12 Gy, and a radiologic and audiologic follow-up {>=}1 year post-GKR. The volume of both the entire tumor and the intracanalicular part of the tumor and the mean and integrated dose of these two volumes were correlated to the auditorymore » outcomes of patients. Results: At last hearing follow-up, 52 patients had no hearing worsening, and 30 patients had an increase of {>=}1 class on Gardner-Robertson classification. We found that hearing preservation after GKR is significantly correlated with the intracanalicular tumor volume, as well as with the integrated dose delivered to the intracanalicular tumor volume. Conclusions: Some volumetric and dosimetric parameters of the intracanalicular part of the tumor influence hearing preservation after GKR of VS. Consequently, we advise the direct treatment of patients with preserved functional hearing and a VS including a small intracanalicular volume.« less

  11. Out of field dose during Gamma Knife treatment: a paediatric case study

    NASA Astrophysics Data System (ADS)

    Moutrie, V.; Grace, M.; Izard, M. A.; Fuller, J. W.

    2017-01-01

    An 11-year-old girl with an arteriovenous malformation (AVM) was referred for Gamma Knife treatment. As this would be the first paediatric treatment in Australia, additional investigations were undertaken into out of field dose to assure the best possible long term outcome for the patient. A phantom was constructed from water equivalent materials to simulate the patient. A target volume was defined to emulate the size and location of the AVM visible in diagnostic images. An ionisation chamber and EBT3 Gafchromic film were used to record absorbed dose at strategic points both on the surface and at depth within the phantom. On the day of treatment, EBT3 Gafchromic film was used to conduct in vivo dosimetry. The pre-treatment phantom measurements matched the planning system for the cranial section (the only modelled section) and no measurable dose above background was detected in the extracranial sites. In vivo measurements of the lenses returned doses of up to 2 cGy for imaging and 8 cGy for treatment which was also consistent with the planned dose. Dose to the thyroid, chest and abdomen was not measurable above background.

  12. SU-E-T-213: Comparison of Treatment Efficiency of Gamma Knife SRS Plans for Brain Metastases with Different Planning Methods

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Feng, Y; Huang, Z; Lo, S

    2015-06-15

    Purpose: To improve Gamma Knife SRS treatment efficiency for brain metastases and compare the differences of treatment time and radiobiological effects between two different planning methods of automatic filling and manual placement of shots with inverse planning. Methods: T1-weighted MRI images with gadolinium contrast from five patients with a single brain metastatic-lesion were used in this retrospective study. Among them, two were from primary breast cancer, two from primary melanoma cancer and one from primary prostate cancer. For each patient, two plans were generated in Leksell GammaPlan10.1.1 for radiosurgical treatment with a Leksell GammaKnife Perfexion machine: one with automatic filling,more » automatic sector configuration and inverse optimization (Method1); and the other with manual placement of shots, manual setup of collimator sizes, manual setup of sector blocking and inverse optimization (Method2). Dosimetric quality of the plans was evaluated with parameters of Coverage, Selectivity, Gradient-Index and DVH. Beam-on Time, Number-of-Shots and Tumor Control Probability(TCP) were compared for the two plans while keeping their dosimetric quality very similar. Relative reduction of Beam-on Time and Number-of-Shots were calculated as the ratios among the two plans and used for quantitative analysis. Results: With very similar dosimetric and radiobiological plan quality, plans created with Method 2 had significantly reduced treatment time. Relative reduction of Beam-on Time ranged from 20% to 51 % (median:29%,p=0.001), and reduction of Number-of-Shots ranged from 5% to 67% (median:40%,p=0.0002), respectively. Time of plan creation for Method1 and Method2 was similar, approximately 20 minutes, excluding the time for tumor delineation. TCP calculated for the tumors from differential DVHs did not show significant difference between the two plans (p=0.35). Conclusion: The method of manual setup combined with inverse optimization in LGP for treatment of

  13. In vivo imaging of endothelial cell adhesion molecule expression after radiosurgery in an animal model of arteriovenous malformation.

    PubMed

    Raoufi-Rad, Newsha; McRobb, Lucinda S; Lee, Vivienne S; Bervini, David; Grace, Michael; Ukath, Jaysree; Mchattan, Joshua; Sreenivasan, Varun K A; Duong, T T Hong; Zhao, Zhenjun; Stoodley, Marcus A

    2017-01-01

    Focussed radiosurgery may provide a means of inducing molecular changes on the luminal surface of diseased endothelium to allow targeted delivery of novel therapeutic compounds. We investigated the potential of ionizing radiation to induce surface expression of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) on endothelial cells (EC) in vitro and in vivo, to assess their suitability as vascular targets in irradiated arteriovenous malformations (AVMs). Cultured brain microvascular EC were irradiated by linear accelerator at single doses of 0, 5, 15 or 25 Gy and expression of ICAM-1 and VCAM-1 measured by qRT-PCR, Western, ELISA and immunocytochemistry. In vivo, near-infrared (NIR) fluorescence optical imaging using Xenolight 750-conjugated ICAM-1 or VCAM-1 antibodies examined luminal biodistribution over 84 days in a rat AVM model after Gamma Knife surgery at a single 15 Gy dose. ICAM-1 and VCAM-1 were minimally expressed on untreated EC in vitro. Doses of 15 and 25 Gy stimulated expression equally; 5 Gy was not different from the unirradiated. In vivo, normal vessels did not bind or retain the fluorescent probes, however binding was significant in AVM vessels. No additive increases in probe binding were found in response to radiosurgery at a dose of 15 Gy. In summary, radiation induces adhesion molecule expression in vitro but elevated baseline levels in AVM vessels precludes further induction in vivo. These molecules may be suitable targets in irradiated vessels without hemodynamic derangement, but not AVMs. These findings demonstrate the importance of using flow-modulated, pre-clinical animal models for validating candidate proteins for vascular targeting in irradiated AVMs.

  14. Stereotactic Radiosurgery for Patients With Brain Metastases From Small Cell Lung Cancer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wegner, Rodney E.; Olson, Adam C.; Kondziolka, Douglas

    2011-11-01

    Background: Patients with small-cell lung cancer have a high likelihood of developing brain metastases. Many of these patients will have prophylactic cranial irradiation (PCI) or eventually undergo whole brain radiation therapy (WBRT). Despite these treatments, a large number of these patients will have progression of their intracranial disease and require additional local therapy. Stereotactic radiosurgery (SRS) is an important treatment option for such patients. Methods: We retrospectively reviewed the charts of 44 patients with brain metastases from small-cell lung cancer treated with gamma knife SRS. Multivariate analysis was used to determine significant prognostic factors influencing survival. Results: The median follow-upmore » from SRS in this patient population was 9 months (1-49 months). The median overall survival (OS) was 9 months after SRS. Karnofsky performance status (KPS) and combined treatment involving WBRT and SRS within 4 weeks were the two factors identified as being significant predictors of increased OS (p = 0.033 and 0.040, respectively). When comparing all patients, patients treated with a combined approach had a median OS of 14 months compared to 6 months if SRS was delivered alone. We also compared the OS times from the first definitive radiation: WBRT, WBRT and SRS if combined therapy was used, and SRS if the patient never received WBRT. The median survival for those groups was 12, 14, and 13 months, respectively, p = 0.19. Seventy percent of patients had follow-up magnetic resonance imaging available for review. Actuarial local control at 6 months and 12 months was 90% and 86%, respectively. Only 1 patient (2.2%) had symptomatic intracranial swelling related to treatment, which responded to a short course of steroids. New brain metastases outside of the treated area developed in 61% of patients at a median time of 7 months; 81% of these patients had received previous WBRT. Conclusions: Stereotactic radiosurgery for small-cell lung

  15. In memoriam Ladislau Steiner, neurosurgeon: some people from transylvania do live forever.

    PubMed

    Dinca, Eduard B; Ciurea, Alexandru V; Valéry, Charles-Ambroise

    2014-01-01

    We review the extraordinary professional trajectory of Ladislau Steiner, a prolific neurosurgeon and radiosurgeon, who died earlier this year. Dr. Steiner trained and practiced as a neurosurgeon in his native Romania until he was 42, before moving to Stockholm. After 25 years at the Karolinska Institute, when most people consider retirement, he spent the following 25 years of his life as director of the Lars Leksell Center for Gamma Knife Radiosurgery at the University of Virginia, Charlottesville, Virginia. At 90, nostalgia for Europe made him accept the position of director of the Gamma Knife Center at the International Neuroscience Institute in Hannover, Germany. His life was dedicated to the 15,000 patients whose lives he saved in his lengthy career. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Stereotactic Radiosurgery for Intracranial Ependymomas: An International Multicenter Study.

    PubMed

    Kano, Hideyuki; Su, Yan-Hua; Wu, Hsiu-Mei; Simonova, Gabriela; Liscak, Roman; Cohen-Inbar, Or; Sheehan, Jason P; Meola, Antonio; Sharma, Mayur; Barnett, Gene H; Mathieu, David; Vasas, Lucas T; Kaufmann, Anthony M; Jacobs, Rachel C; Lunsford, L Dade

    2018-03-28

    Stereotactic radiosurgery (SRS) is a potentially important option for intracranial ependymoma patients. To analyze the outcomes of intracranial ependymoma patients who underwent SRS as a part of multimodality management. Seven centers participating in the International Gamma Knife Research Foundation identified 89 intracranial ependymoma patients who underwent SRS (113 tumors). The median patient age was 16.3 yr (2.9-80). All patients underwent previous surgical resection and radiation therapy (RT) of their ependymomas and 40 underwent previous chemotherapy. Grade 2 ependymomas were present in 42 patients (52 tumors) and grade 3 ependymomas in 48 patients (61 tumors). The median tumor volume was 2.2 cc (0.03-36.8) and the median margin dose was 15 Gy (9-24). Forty-seven (53%) patients were alive and 42 (47%) patients died at the last follow-up. The overall survival after SRS was 86% at 1 yr, 50% at 3 yr, and 44% at 5 yr. Smaller total tumor volume was associated with longer overall survival (P = .006). Twenty-two patients (grade 2: n = 9, grade 3: n = 13) developed additional recurrent ependymomas in the craniospinal axis. The progression-free survival after SRS was 71% at 1 yr, 56% at 3 yr, and 48% at 5 yr. Adult age, female sex, and smaller tumor volume indicated significantly better progression-free survival. Symptomatic adverse radiation effects were seen in 7 patients (8%). SRS provides another management option for residual or recurrent progressive intracranial ependymoma patients who have failed initial surgery and RT.

  17. Treatment planning for spinal radiosurgery : A competitive multiplatform benchmark challenge.

    PubMed

    Moustakis, Christos; Chan, Mark K H; Kim, Jinkoo; Nilsson, Joakim; Bergman, Alanah; Bichay, Tewfik J; Palazon Cano, Isabel; Cilla, Savino; Deodato, Francesco; Doro, Raffaela; Dunst, Jürgen; Eich, Hans Theodor; Fau, Pierre; Fong, Ming; Haverkamp, Uwe; Heinze, Simon; Hildebrandt, Guido; Imhoff, Detlef; de Klerck, Erik; Köhn, Janett; Lambrecht, Ulrike; Loutfi-Krauss, Britta; Ebrahimi, Fatemeh; Masi, Laura; Mayville, Alan H; Mestrovic, Ante; Milder, Maaike; Morganti, Alessio G; Rades, Dirk; Ramm, Ulla; Rödel, Claus; Siebert, Frank-Andre; den Toom, Wilhelm; Wang, Lei; Wurster, Stefan; Schweikard, Achim; Soltys, Scott G; Ryu, Samuel; Blanck, Oliver

    2018-05-25

    To investigate the quality of treatment plans of spinal radiosurgery derived from different planning and delivery systems. The comparisons include robotic delivery and intensity modulated arc therapy (IMAT) approaches. Multiple centers with equal systems were used to reduce a bias based on individual's planning abilities. The study used a series of three complex spine lesions to maximize the difference in plan quality among the various approaches. Internationally recognized experts in the field of treatment planning and spinal radiosurgery from 12 centers with various treatment planning systems participated. For a complex spinal lesion, the results were compared against a previously published benchmark plan derived for CyberKnife radiosurgery (CKRS) using circular cones only. For two additional cases, one with multiple small lesions infiltrating three vertebrae and a single vertebra lesion treated with integrated boost, the results were compared against a benchmark plan generated using a best practice guideline for CKRS. All plans were rated based on a previously established ranking system. All 12 centers could reach equality (n = 4) or outperform (n = 8) the benchmark plan. For the multiple lesions and the single vertebra lesion plan only 5 and 3 of the 12 centers, respectively, reached equality or outperformed the best practice benchmark plan. However, the absolute differences in target and critical structure dosimetry were small and strongly planner-dependent rather than system-dependent. Overall, gantry-based IMAT with simple planning techniques (two coplanar arcs) produced faster treatments and significantly outperformed static gantry intensity modulated radiation therapy (IMRT) and multileaf collimator (MLC) or non-MLC CKRS treatment plan quality regardless of the system (mean rank out of 4 was 1.2 vs. 3.1, p = 0.002). High plan quality for complex spinal radiosurgery was achieved among all systems and all participating centers in this

  18. Gamma Knife Surgery for Metastatic Brain Tumors from Gynecologic Cancer.

    PubMed

    Matsunaga, Shigeo; Shuto, Takashi; Sato, Mitsuru

    2016-05-01

    The incidences of metastatic brain tumors from gynecologic cancer have increased. The results of Gamma Knife surgery (GKS) for the treatment of patients with brain metastases from gynecologic cancer (ovarian, endometrial, and uterine cervical cancers) were retrospectively analyzed to identify the efficacy and prognostic factors for local tumor control and survival. The medical records were retrospectively reviewed of 70 patients with 306 tumors who underwent GKS for brain metastases from gynecologic cancer between January 1995 and December 2013 in our institution. The primary cancers were ovarian in 33 patients with 147 tumors and uterine in 37 patients with 159 tumors. Median tumor volume was 0.3 cm(3). Median marginal prescription dose was 20 Gy. The local tumor control rates were 96.4% at 6 months and 89.9% at 1 year. There was no statistically significant difference between ovarian and uterine cancers. Higher prescription dose and smaller tumor volume were significantly correlated with local tumor control. Median overall survival time was 8 months. Primary ovarian cancer, controlled extracranial metastases, and solitary brain metastasis were significantly correlated with satisfactory overall survival. Median activities of daily living (ADL) preservation survival time was 8 months. Primary ovarian cancer, controlled extracranial metastases, and higher Karnofsky Performance Status score were significantly correlated with better ADL preservation. GKS is effective for control of tumor progression in patients with brain metastases from gynecologic cancer, and may provide neurologic benefits and preservation of the quality of life. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Evolution of gamma knife capsulotomy for intractable obsessive-compulsive disorder.

    PubMed

    Miguel, Euripedes C; Lopes, Antonio C; McLaughlin, Nicole C R; Norén, Georg; Gentil, André F; Hamani, Clement; Shavitt, Roseli G; Batistuzzo, Marcelo C; Vattimo, Edoardo F Q; Canteras, Miguel; De Salles, Antonio; Gorgulho, Alessandra; Salvajoli, João Victor; Fonoff, Erich Talamoni; Paddick, Ian; Hoexter, Marcelo Q; Lindquist, Christer; Haber, Suzanne N; Greenberg, Benjamin D; Sheth, Sameer A

    2018-05-09

    For more than half a century, stereotactic neurosurgical procedures have been available to treat patients with severe, debilitating symptoms of obsessive-compulsive disorder (OCD) that have proven refractory to extensive, appropriate pharmacological, and psychological treatment. Although reliable predictors of outcome remain elusive, the establishment of narrower selection criteria for neurosurgical candidacy, together with a better understanding of the functional neuroanatomy implicated in OCD, has resulted in improved clinical efficacy for an array of ablative and non-ablative intervention techniques targeting the cingulum, internal capsule, and other limbic regions. It was against this backdrop that gamma knife capsulotomy (GKC) for OCD was developed. In this paper, we review the history of this stereotactic radiosurgical procedure, from its inception to recent advances. We perform a systematic review of the existing literature and also provide a narrative account of the evolution of the procedure, detailing how the procedure has changed over time, and has been shaped by forces of evidence and innovation. As the procedure has evolved and adverse events have decreased considerably, favorable response rates have remained attainable for approximately one-half to two-thirds of individuals treated at experienced centers. A reduction in obsessive-compulsive symptom severity may result not only from direct modulation of OCD neural pathways but also from enhanced efficacy of pharmacological and psychological therapies working in a synergistic fashion with GKC. Possible complications include frontal lobe edema and even the rare formation of delayed radionecrotic cysts. These adverse events have become much less common with new radiation dose and targeting strategies. Detailed neuropsychological assessments from recent studies suggest that cognitive function is not impaired, and in some domains may even improve following treatment. We conclude this review with

  20. Role of radiosurgery in craniopharyngiomas: a preliminary report.

    PubMed

    Amendola, Beatriz E; Wolf, Aizik; Coy, Sammie R; Amendola, Marco A

    2003-08-01

    The purpose of this retrospective review is to evaluate our experience using radiosurgery in the management of craniopharyngiomas. Fourteen patients, 6 males and 8 females, ages ranging from 3 to 44 years of age, were treated with radiosurgery from February 1994 through December 2000 for primary or recurrent craniopharyngioma. There were two adults and 12 children. All patients were treated with the Leksell Gamma units Model U or C. The mean minimum dose was 14 Gy ranging from 11 to 20 Gy and the mean maximum dose was 29 Gy ranging from 24 to 40 Gy. Volume of treatment ranged from 0.1 to 26.5 cm(3). The dose to critical structures was below 8 Gy to the optic chiasm and below 14 Gy to the brain stem. One of the 14 patients had previous conventional radiation therapy. All patients are alive and with out evidence of recurrent disease 6-86 months after treatment. Only two patients required retreatment. Although craniopharyngioma is a benign tumor, its location makes even advanced microsurgical techniques difficult to perform. Radiosurgery obviates the shortcomings of surgical resection near the hypothalamic-pituitary axis without the morbidity of open surgery. Copyright 2003 Wiley-Liss, Inc.

  1. Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Leavitt, Jacqueline A., E-mail: leavitt.jacqueline@mayo.edu; Stafford, Scott L.; Link, Michael J.

    2013-11-01

    Purpose: To determine the long-term risk of radiation-induced optic neuropathy (RION) in patients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Methods and Materials: Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0more » Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). Results: The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). Conclusions: The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy.« less

  2. Predicting treatment related imaging changes (TRICs) after radiosurgery for brain metastases using treatment dose and conformality metrics.

    PubMed

    Taylor, B Frazier; Knisely, Jonathan P; Qian, Jack M; Yu, James B; Chiang, Veronica L

    2016-01-01

    Treatment-related imaging changes (TRICs) after stereotactic radiosurgery (SRS) involves the benign transient enlargement of radiographic lesions after treatment. Identifying the radiation dose volumes and conformality metrics associated with TRICs for different post-treatment periods would be helpful and improve clinical decision making. 367 metastases in 113 patients were treated using Gamma Knife SRS between 1/1/2007-12/31/2009. Each metastasis was measured at each imaging follow-up to detect TRICs (defined as ≥ 20% increase in volume). Fluctuations in small volume lesions (less than 108 mm 3 ) were ignored given widely variable conformity indices (CI) for small volumes. The Karolinska Adverse Radiation Effect (KARE) factor, Paddick's CI, Shaw's CI, tumor volume (TV), 10 Gy (V10) and 12 Gy (V12) volumes, and prescription isodose volume (PIV) were calculated. From 0-6 months, all measures correlated with the incidence of TRICs (p<.001), except KARE, which was inversely correlated. During the 6-12 month period all measures except KARE were still correlated. Beyond 12 months, no correlation was found between any of the measures and the development of TRICs. All metrics except KARE were associated with TRICs from 0-12 months only. Additional patient and treatment factors may become dominant at greater times after SRS.

  3. Ladislau Steiner, 1920-2013.

    PubMed

    Leksell, Dan; Lindquist, Christer E H

    2013-09-01

    The authors commemorate the life and career of Dr. Ladislau Steiner, one of the world's most highly regarded neurosurgeons, from Stockholm and Charlottesville, Virginia, who has died at age 92. They review the events of Dr. Steiner's early life, including his early training in his native Romania, his escape with his family from East Berlin, and his postgraduate training in neurosurgery at the Karolinska Institute in Stockholm. Dr. Steiner's work in the development of microsurgery and his collaboration with Lars Leksell in the development of Gamma Knife radiosurgery are described. After his retirement from Karolinska, Dr. Steiner had a second career as head of the Lars Leksell Gamma Knife Center at the University of Virginia in Charlottesville. The authors recall their own long association with Dr. Steiner and celebrate his contributions to the field of neurosurgery.

  4. Implementation of Monte Carlo Dose calculation for CyberKnife treatment planning

    NASA Astrophysics Data System (ADS)

    Ma, C.-M.; Li, J. S.; Deng, J.; Fan, J.

    2008-02-01

    Accurate dose calculation is essential to advanced stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) especially for treatment planning involving heterogeneous patient anatomy. This paper describes the implementation of a fast Monte Carlo dose calculation algorithm in SRS/SRT treatment planning for the CyberKnife® SRS/SRT system. A superposition Monte Carlo algorithm is developed for this application. Photon mean free paths and interaction types for different materials and energies as well as the tracks of secondary electrons are pre-simulated using the MCSIM system. Photon interaction forcing and splitting are applied to the source photons in the patient calculation and the pre-simulated electron tracks are repeated with proper corrections based on the tissue density and electron stopping powers. Electron energy is deposited along the tracks and accumulated in the simulation geometry. Scattered and bremsstrahlung photons are transported, after applying the Russian roulette technique, in the same way as the primary photons. Dose calculations are compared with full Monte Carlo simulations performed using EGS4/MCSIM and the CyberKnife treatment planning system (TPS) for lung, head & neck and liver treatments. Comparisons with full Monte Carlo simulations show excellent agreement (within 0.5%). More than 10% differences in the target dose are found between Monte Carlo simulations and the CyberKnife TPS for SRS/SRT lung treatment while negligible differences are shown in head and neck and liver for the cases investigated. The calculation time using our superposition Monte Carlo algorithm is reduced up to 62 times (46 times on average for 10 typical clinical cases) compared to full Monte Carlo simulations. SRS/SRT dose distributions calculated by simple dose algorithms may be significantly overestimated for small lung target volumes, which can be improved by accurate Monte Carlo dose calculations.

  5. Upfront boost Gamma Knife "leading-edge" radiosurgery to FLAIR MRI-defined tumor migration pathways in 174 patients with glioblastoma multiforme: a 15-year assessment of a novel therapy.

    PubMed

    Duma, Christopher M; Kim, Brian S; Chen, Peter V; Plunkett, Marianne E; Mackintosh, Ralph; Mathews, Marlon S; Casserly, Ryan M; Mendez, Gustavo A; Furman, Daniel J; Smith, Garrett; Oh, Nathan; Caraway, Chad A; Sanathara, Ami R; Dillman, Robert O; Riley, Azzurra-Sky; Weiland, David; Stemler, Lian; Cannell, Ruslana; Abrams, Daniela Alexandru; Smith, Alexa; Owen, Christopher M; Eisenberg, Burton; Brant-Zawadzki, Michael

    2016-12-01

    OBJECTIVE Glioblastoma multiforme (GBM) is composed of cells that migrate through the brain along predictable white matter pathways. Targeting white matter pathways adjacent to, and leading away from, the original contrast-enhancing tumor site (termed leading-edge radiosurgery [LERS]) with single-fraction stereotactic radiosurgery as a boost to standard therapy could limit the spread of glioma cells and improve clinical outcomes. METHODS Between December 2000 and May 2016, after an initial diagnosis of GBM and prior to or during standard radiation therapy and carmustine or temozolomide chemotherapy, 174 patients treated with radiosurgery to the leading edge (LE) of tumor cell migration were reviewed. The LE was defined as a region outside the contrast-enhancing tumor nidus, defined by FLAIR MRI. The median age of patients was 59 years (range 22-87 years). Patients underwent LERS a median of 18 days from original diagnosis. The median target volume of 48.5 cm 3 (range 2.5-220.0 cm 3 ) of LE tissue was targeted using a median dose of 8 Gy (range 6-14 Gy) at the 50% isodose line. RESULTS The median overall survival was 23 months (mean 43 months) from diagnosis. The 2-, 3-, 5-, 7-, and 10-year actual overall survival rates after LERS were 39%, 26%, 16%, 10%, and 4%, respectively. Nine percent of patients developed treatment-related imaging-documented changes due to LERS. Nineteen percent of patients were hospitalized for management of edema, 22% for resection of a tumor cyst or new tumor bulk, and 2% for shunting to treat hydrocephalus throughout the course of their disease. Of the patients still alive, Karnofsky Performance Scale scores remained stable in 90% of patients and decreased by 1-3 grades in 10% due to symptomatic treatment-related imaging changes. CONCLUSIONS LERS is a safe and effective upfront adjunctive therapy for patients with newly diagnosed GBM. Limitations of this study include a single-center experience and single-institution determination of the

  6. SU-E-J-64: Feasibility Study of Surgical Clips for Fiducial Tracking in CyberKnife System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lee, H; Yoon, J; Lee, E

    Purpose: To investigate the ability of CyberKnife to track surgical clips used as fiducial markers. Methods: The Octavius 1000SRS detector and solid water (RW3) slab phantom were used with motion platform to evaluate the study. The RW3 slab phantom was set up to measure the dose distribution from coronal plane. It consists of 9 plates and the thickness of each plate is 10mm. Among them, one plate was attached with 3 surgical clips, which are orthogonally positioned on outer region of array. The length of attached clip was represented as 1cm on planning CT. The clip plate was placed onmore » the 1000SRS detector and 3 slabs were stacked up on the plate to build the measuring depth. Below the detector, 5 slabs were set. The two-axis motion platform was programmed with 1D sinusoidal movement (20mm peak-to-peak, 3s period) toward superior/inferior and left/right directions to simulate target motion. During delivery, two clips were extracted by two X-ray imagers, which led to translational error correction only. Synchrony was also used for dynamic tracking. After the irradiation, the measured dose distribution of coronal plane was compared with the planar dose distribution calculated by the CyberKnife treatment planning system (Multiplan) for cross verification. The results were assessed by comparing the absolute Gamma (γ) index. Results: The dose distributions measured by the 1000SRS detector were in good agreements with those calculated by Multiplan. In the dosimetric comparison using γ-function criteria based on the distance-to-agreement of 3mm and the local dose difference of 3%, the passing rate with γ- parameter ≤1 was 91% in coronal plane. Conclusion: The surgical clips can be considered as new fiducials for robotic radiosurgery delivery by considering the target margin with less than 5mm.« less

  7. The efficacy of fractionated radiotherapy and stereotactic radiosurgery for pituitary adenomas: long-term results of 125 consecutive patients treated in a single institution.

    PubMed

    Kong, Doo-Sik; Lee, Jung-Il; Lim, Do Hoon; Kim, Kwang Won; Shin, Hyung Jin; Nam, Do-Hyun; Park, Kwan; Kim, Jong Hyun

    2007-08-15

    The objective of this retrospective cohort study was to define the efficacy and safety of fractionated radiotherapy (FRT) and stereotactic radiosurgery (SRS) for the treatment of patients with pituitary adenoma. Between January 1995 and April 2006, 125 consecutive patients with pituitary adenomas (54 hormone-secreting adenomas and 71 nonsecretory adenomas) received FRT or underwent SRS. Sixty-four patients received FRT, for which the mean total dose was 50.4 grays (Gy) (range, 48-54 Gy), and 61 patients underwent gamma-knife SRS with mean marginal dose of 25.1 Gy (range, 9-30 Gy). After mean follow up of 36.7 months, the tumor volume was increased in only 4 patients (3.2%). The overall actuarial progression-free survival rate was 99% at 2 years and 97% at 4 years. No difference was observed between the FRT group and the SRS group in the control of tumor growth. Based on the endocrinologic results in the patients who had secretory adenomas, the overall hormone complete remission rate was 26.2% at 2 years and 76.3% at 4 years. The median time to complete remission was 26 months in the SRS group and 63 months in the FRT group (P = .0068). Hypopituitarism developed as a delayed complication in 11.5% of patients at a median of 84 months. Both FRT and SRS were efficient treatment modalities for the control of tumor growth in patients with pituitary adenomas. The current results indicated that single-dose radiosurgery more promptly produces an effect on the hypersecretion of pituitary hormones and may be recommended over FRT for suitable patients.

  8. Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions

    PubMed Central

    Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A.

    2013-01-01

    Purpose: To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife® based stereotactic radiosurgery (GKSR) prior to treatment. Methods: Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7–80), mean number of lesions of 2.5 (range 1–6), and mean lesion volume of 4.4 cm3 (range 0.02–22.2 cm3)] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. Results: In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. Conclusions: The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions. PMID:24007147

  9. Intravascular Placement of Metallic Coils as Lung Tumor Markers for CyberKnife Stereotactic Radiation Therapy.

    PubMed

    Karaman, Kutlay; Dokdok, A Murat; Karadeniz, Oktay; Ceylan, Cemile; Engin, Kayıhan

    2015-01-01

    To present our experience with placing endovascular coils in pulmonary arteries used as a fiducial marker for CyberKnife therapy and to describe the technical details and complications of the procedure. Between June 2005 and September 2013, 163 patients with primary or secondary lung malignancies, referred for fiducial placement for stereotactic radiosurgery, were retrospectively reviewed. Fourteen patients (9 men, 5 women; mean age, 70 years) with a history of pneumonectomy (n = 3), lobectomy (n = 3) or with severe cardiopulmonary co-morbidity (n = 8) underwent coil (fiducial marker) placement. Pushable or detachable platinum micro coils (n = 49) 2-3 mm in size were inserted through coaxial microcatheters into a small distal pulmonary artery in the vicinity of the tumor under biplane angiography/fluoroscopy guidance. Forty nine coils with a median number of 3 coils per tumor were placed with a mean tumor-coil distance of 2.7 cm. Forty three (87.7%) of 49 coils were successfully used as fiducial markers. Two coils could not be used due to a larger tumor-coil distance (> 50 mm). Four coils were in an acceptable position but their non-coiling shape precluded tumor tracking for CyberKnife treatment. No major complications needing further medication other than nominal therapy, hospitalization more than one night or permanent adverse sequale were observed. Endovascular placement of coil as a fiducial marker is safe and feasible during CyberKnife therapy, and might be an option for the patients in which percutaneous transthoracic fiducial placement might be risky.

  10. OS03.4 Gammaknife versus Linac based (EDGE) radiosurgery (SRS) for patients with limited brain metastases (BMS) from different solid tumor: a phase III randomized trial.

    PubMed Central

    Scorsetti, M.; Navarria, P.; Ascolese, A.; Clerici, E.; Mancosu, P.; Picozzi, P.; Pecchioli, G.; Franzese, C.; Reggiori, G.; Tomatis, S.

    2017-01-01

    Abstract Introduction: Radiosurgery is an emerging terapeutich approach for the treatment of brain metastases (BMs), considering the effective local control obtained without neurological impairment. Different technological modalities have been used: Gammaknife, Cybernife, or Linac with comparable results and different incidence of symptomatic radionecrosis. To date no comparative randomized studies have been published on this matter. We draw this randomized phase III trial with the aim to evaluate incidence of symptomatic radionecrosis using gamma knife radiosurgery versus linac based (EDGE) radiosurgery. Local control (LC) rate and patients overall survival (OS) were assessed as well. Materials: Patients with limited BMs (up to 4) from different solid tumors, except SCLC or hematologic malignancies, were enrolled. Inclusion criteria were a histopatological diagnosis of malignant primary tumor, a KPS ≥70, RPA class I-II, and BMs with maximum diameter ≤3 cm and/or with a total tumor volume <30 cm3. The total dose prescribed was 24 Gy for BMs ≤ 20 mm or 4.2 cm3, and 20 Gy for BMs 21–30 mm or volume <14.1 cm3 as suggested by RTOG guidelines. Clinical outcome was evaluated by neurological examination and MRI at 2 months after SRS and then every 3 months. The radionecrosis was considered the presence of central hypodensity and peripheral enhancement on T1-weighted post-contrast imaging, with edema on T2-weighted sequences and a clear lack of perfusion without any nodular highly vascularized area within the contrast enhanced lesion on perfusion MRI. Local progression was defined as radiographic increase of the enhancing abnormality in the irradiated volume on serial MR imaging, and distant failure by the presence of new brain metastases or leptomeningeal enhancement outside the irradiated volume. Results: From October 2014 to December 2015, 101 consecutives patients of the expected 250, for 167 BMs treated, were evaluated. The most common primary

  11. Usefulness of a novel slim type FlushKnife-BT over conventional FlushKnife-BT in esophageal endoscopic submucosal dissection.

    PubMed

    Ohara, Yoshiko; Toyonaga, Takashi; Hoshi, Namiko; Tanaka, Shinwa; Baba, Shinichi; Takihara, Hiroshi; Kawara, Fumiaki; Ishida, Tsukasa; Morita, Yoshinori; Umegaki, Eiji; Azuma, Takeshi

    2017-03-07

    To investigated the usefulness of a novel slim type ball-tipped FlushKnife (FlushKnife-BTS) over ball-tipped FlushKnife (FlushKnife-BT) in functional experiments and clinical practice. In order to evaluate the functionality of FlushKnife-BTS, water aspiration speed, resistance to knife insertion through the scope, and waterjet flushing speed were compared between FlushKnife-BTS and BT. In clinical practice, esophageal endoscopic submucosal dissection (ESD) performed using FlushKnife-BTS or BT by an experienced endoscopist between October 2015 and January 2016 were retrospectively reviewed. The treatment speed and frequency of removing and reinserting the knife to aspirate fluid and air during ESD sessions were analyzed. Functional experiments revealed that water aspiration speed by the endoscope equipped with a 2.8-mm working channel with FlushKnife-BTS was 7.7-fold faster than that with conventional FlushKnife-BT. Resistance to knife insertion inside the scope with a 2.8-mm working channel was reduced by 40% with FlushKnife-BTS. The waterjet flushing speed was faster with the use of FlushKnife-BT. In clinical practice, a comparison of 6 and 7 ESD using FlushKnife-BT and BTS, respectively, revealed that the median treatment speed was 25.5 mm 2 /min (range 19.6-30.3) in the BT group and 44.2 mm 2 /min (range 15.5-55.4) in the BTS group ( P = 0.0633). However, the median treatment speed was significantly faster with FlushKnife-BTS when the resection size was larger than 1000 m 2 ( n = 4, median 24.2 mm 2 /min, range 19.6-27.7 vs n = 4, median 47.4 mm 2 /min, range 44.2-55.4, P = 0.0209). The frequency of knife replacement was less in the BTS group (median 1.76 times in one hour, range 0-5.45) than in the BT group (7.02 times in one hour, range 4.23-15) ( P = 0.0065). Our results indicate that FlushKnife-BTS enhances the performance of ESD, particularly for large lesions, by improving air and fluid aspiration and knife insertion during ESD and reducing the frequency

  12. Usefulness of a novel slim type FlushKnife-BT over conventional FlushKnife-BT in esophageal endoscopic submucosal dissection

    PubMed Central

    Ohara, Yoshiko; Toyonaga, Takashi; Hoshi, Namiko; Tanaka, Shinwa; Baba, Shinichi; Takihara, Hiroshi; Kawara, Fumiaki; Ishida, Tsukasa; Morita, Yoshinori; Umegaki, Eiji; Azuma, Takeshi

    2017-01-01

    AIM To investigated the usefulness of a novel slim type ball-tipped FlushKnife (FlushKnife-BTS) over ball-tipped FlushKnife (FlushKnife-BT) in functional experiments and clinical practice. METHODS In order to evaluate the functionality of FlushKnife-BTS, water aspiration speed, resistance to knife insertion through the scope, and waterjet flushing speed were compared between FlushKnife-BTS and BT. In clinical practice, esophageal endoscopic submucosal dissection (ESD) performed using FlushKnife-BTS or BT by an experienced endoscopist between October 2015 and January 2016 were retrospectively reviewed. The treatment speed and frequency of removing and reinserting the knife to aspirate fluid and air during ESD sessions were analyzed. RESULTS Functional experiments revealed that water aspiration speed by the endoscope equipped with a 2.8-mm working channel with FlushKnife-BTS was 7.7-fold faster than that with conventional FlushKnife-BT. Resistance to knife insertion inside the scope with a 2.8-mm working channel was reduced by 40% with FlushKnife-BTS. The waterjet flushing speed was faster with the use of FlushKnife-BT. In clinical practice, a comparison of 6 and 7 ESD using FlushKnife-BT and BTS, respectively, revealed that the median treatment speed was 25.5 mm2/min (range 19.6-30.3) in the BT group and 44.2 mm2/min (range 15.5-55.4) in the BTS group (P = 0.0633). However, the median treatment speed was significantly faster with FlushKnife-BTS when the resection size was larger than 1000 m2 (n = 4, median 24.2 mm2/min, range 19.6-27.7 vs n = 4, median 47.4 mm2/min, range 44.2-55.4, P = 0.0209). The frequency of knife replacement was less in the BTS group (median 1.76 times in one hour, range 0-5.45) than in the BT group (7.02 times in one hour, range 4.23-15) (P = 0.0065). CONCLUSION Our results indicate that FlushKnife-BTS enhances the performance of ESD, particularly for large lesions, by improving air and fluid aspiration and knife insertion during ESD and

  13. Gamma knife treatment for refractory epilepsy in seizure focus localized by positron emission tomography/CT★

    PubMed Central

    Bai, Xia; Wang, Xuemei; Wang, Hongwei; Zhao, Shigang; Han, Xiaodong; Hao, Linjun; Wang, Xiangcheng

    2012-01-01

    A total of 80 patients with refractory epilepsy were recruited from the Inner Mongolia Medical College Affiliated Hospital. The foci of 60% of the patients could be positioned using a combined positron emission tomography/CT imaging modality. Hyper- and hypometabolism foci were examined as part of this study. Patients who had abnormal metabolism in positron emission tomography/CT imaging were divided into intermittent-phase group and the seizure-phase group. The intermittent-phase group was further divided into a single-focus group and a multiple-foci group according to the number of seizure foci detected by imaging. Following gamma knife treatment, seizure frequency was significantly lower in the intermittent-phase group and the seizure-phase group. Wieser’s classification reached Grade I or II in nearly 40% of patients. Seizure frequency was significantly lower following treatment, but Wieser’s classification score was significantly higher in the seizure-phase group compared with the intermittent-phase group. Seizure frequency was significantly lower following treatment in the single-focus group, but Wieser’s classification score was significantly higher in the single-focus group as compared with the multiple-foci group. PMID:25317147

  14. SU-F-T-576: Characterization of Two Dimensional Liquid Filled Detector Array(SRS 1000) in High Precision Cyberknife Robotic Radiosurgery System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Muthukumaran, M; Manigandan, D; Murali, V

    Purpose: The aim of the study is to characterize a two dimensional liquid filled detector array SRS 1000 for routine QA in Cyberknife Robotic Radiosurgery system. Methods: SRS 1000 consists of 977 liquid filled ionization chambers and is designed to be used in small field SRS/SBRT techniques. The detector array has got two different spacial resolutions. Till field size of 5.5×5.5 cm the spacial resolution is 2.5mm (center to center) and after that till field size of 11 × 11 cm the spacial resolution is 5mm. The size of the detector is 2.3 × 2.3 0.5 mm with a volumemore » of .003 cc. The CyberKnife Robotic Radiosurgery System is a frameless stereotactic radiosurgery system in which a LINAC is mounted on a robotic manipulator to deliver beams with a high sub millimeter accuracy. The SRS 1000’s MU linearity, stability, reproducibility in Cyberknife Robotic Radiosurgery system was measured and investigated. The output factors for fixed and IRIS collimators for all available collimators (5mm till 60 mm) was measured and compared with the measurement done with PTW pin-point ionization chamber. Results: The MU linearity was measured from 2 MU till 1000 MU for doserates in the range of 700cGy/min – 780 cGy/min and compared with the measurement done with pin point chamber The MU linearity was with in 3%. The detector arrays stability and reproducibility was excellent and was withinin 0.5% The measured output factors showed an agreement of better than 2% when compared with the measurements with pinpoint chamber for both fixed and IRIS collimators with all available field sizes. Conclusion: We have characterised PTW 1000 SRS as a precise and accurate measurement tool for routine QA of Cyberknife Robotic radiosurgery system.« less

  15. Maintaining knife sharpness in industrial meat cutting: A matter of knife or meat cutter ability.

    PubMed

    Karltun, J; Vogel, K; Bergstrand, M; Eklund, J

    2016-09-01

    Knife sharpness is imperative in meat cutting. The aim of this study was to compare the impact of knife blade steel quality with meat cutters' individual ability to maintain the cutting edge sharp in an industrial production setting. Twelve meat cutters in two different companies using three different knives during normal production were studied in this quasi-experimental study. Methods included were measuring knife cutting force before and after knife use, time knives were used, ratings of sharpness and discomfort and interviews. Results showed that the meat cutters' skill of maintaining sharpness during work had a much larger effect on knife sharpness during work than the knife steel differences. The ability was also related to feelings of discomfort and to physical exertion. It was found that meat cutters using more knives were more likely to suffer from discomfort in the upper limbs, which is a risk for developing MSD. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Interfraction and intrafraction performance of the Gamma Knife Extend system for patient positioning and immobilization.

    PubMed

    Schlesinger, David; Xu, Zhiyuan; Taylor, Frances; Yen, Chun-Po; Sheehan, Jason

    2012-12-01

    The Extend system for the Gamma Knife Perfexion makes possible multifractional Gamma Knife treatments. The Extend system consists of a vacuum-monitored immobilization frame and a positioning measurement system used to determine the location of the patient's head within the frame at the time of simulation imaging and before each treatment fraction. The measurement system consists of a repositioning check tool (RCT), which attaches to the Extend frame, and associated digital measuring gauges. The purpose of this study is to evaluate the performance of the Extend system for patient repositioning before each treatment session (fraction) and patient immobilization between (interfraction) and during (intrafraction) each session in the first 10 patients (36 fractional treatments) treated at the University of Virginia. The RCT was used to acquire a set of reference measurements for each patient position at the time of CT simulation. Repositioning measurements were acquired before each fraction, and the patient position was adjusted until the residual radial difference from the reference position measurements was less than 1 mm. After treatment, patient position measurements were acquired, and the difference between those measurements and the ones obtained for patient position before the fraction was calculated as a measure of immobilization capability. Analysis of patient setup and immobilization performance included calculation of the group mean, standard deviation (SD), and distribution of systematic (components affecting all fractions) and random (per fraction) uncertainty components. Across all patients and fractions, the mean radial setup difference from the reference measurements was 0.64 mm, with an SD of 0.24 mm. The distribution of systematic uncertainty (Σ) was 0.17 mm, and the distribution of random uncertainty (σ) was 0.16 mm. The root mean square (RMS) differences for each plate of the RCT were as follows: right = 0.35 mm; left = 0.41 mm; superior = 0.28 mm

  17. The Shoemaker's Knife

    ERIC Educational Resources Information Center

    Thomson, Ian

    2010-01-01

    Archimedes, the famous Greek mathematician, lived from 287 BCE until approximately 212 BCE. He thought that the figure of two semi-circles on a straight line enclosed by a larger semi-circle resembled a shoemaker's knife. Archimedes called this figure an "arbelos" since arbelos is the Greek word for a shoemaker's knife. The author describes the…

  18. Gamma knife surgery for epilepsy related to hypothalamic hamartomas.

    PubMed

    Régis, J; Bartolomei, F; de Toffol, B; Genton, P; Kobayashi, T; Mori, Y; Takakura, K; Hori, T; Inoue, H; Schröttner, O; Pendl, G; Wolf, A; Arita, K; Chauvel, P

    2000-12-01

    Drug-resistant epilepsy associated with hypothalamic hamartomas (HHs) can be cured by microsurgical resection of the lesions. Morbidity and mortality rates for microsurgery in this area are significant. Gamma knife surgery (GKS) is less invasive and seems to be well adapted for this indication. To evaluate the safety and efficacy of GKS to treat this uncommon pathological condition, we organized a multicenter retrospective study. Ten patients were treated in seven different centers. The follow-up periods were more than 12 months for eight patients, with a median follow-up period of 28 months (mean, 35 mo; range, 12-71 mo). All patients had severe drug-resistant epilepsy, including frequent gelastic and generalized tonic or tonicoclonic attacks. The median age was 13.5 years (range, 1-32 yr; mean, 14 yr) at the time of GKS. Three patients experienced precocious puberty. All patients had sessile HHs. The median marginal dose was 15.25 Gy (range, 12-20 Gy). Two patients were treated two times (at 19 and 49 mo) because of insufficient efficacy. All patients exhibited improvement. Four patients were seizure-free, one experienced rare nocturnal seizures, one experienced some rare partial seizures but no more generalized attacks, and two exhibited only improvement, with reductions in the frequency of seizures but persistence of some rare generalized seizures. Two patients, now seizure-free, were considered to exhibit insufficient improvement after the first GKS procedure and were treated a second time. A clear correlation between efficacy and dose was observed in this series. The marginal dose was more than 17 Gy for all patients in the successful group and less than 13 Gy for all patients in the "improved" group. No side effects were reported, except for poikilothermia in one patient. Behavior was clearly improved for two patients (with only slight improvements in their epilepsy). Complete coverage of the HHs did not seem to be mandatory, because the dosimetry spared a

  19. Radiosurgery planning supported by the GEMSS grid.

    PubMed

    Fenner, J W; Mehrem, R A; Ganesan, V; Riley, S; Middleton, S E; Potter, K; Walton, L

    2005-01-01

    GEMSS (Grid Enabled Medical Simulation Services IST-2001-37153) is an EU project funded to provide a test bed for Grid-enabled health applications. Its purpose is evaluation of Grid computing in the health sector. The health context imposes particular constraints on Grid infrastructure design, and it is this that has driven the feature set of the middleware. In addition to security, the time critical nature of health applications is accommodated by a Quality of Service component, and support for a well defined business model is also included. This paper documents experience of a GEMSS compliant radiosurgery application running within the Medical Physics department at the Royal Hallamshire Hospital in the UK. An outline of the Grid-enabled RAPT radiosurgery application is presented and preliminary experience of its use in the hospital environment is reported. The performance of the software is compared against GammaPlan (an industry standard) and advantages/disadvantages are highlighted. The RAPT software relies on features of the GEMSS middleware that are integral to the success of this application, and together they provide a glimpse of an enabling technology that can impact upon patient management in the 21st century.

  20. Rivaling paradigms in psychiatric neurosurgery: adjustability versus quick fix versus minimal-invasiveness.

    PubMed

    Müller, Sabine; Riedmüller, Rita; van Oosterhout, Ansel

    2015-01-01

    In the wake of deep brain stimulation (DBS) development, ablative neurosurgical procedures are seeing a comeback, although they had been discredited and nearly completely abandoned in the 1970s because of their unethical practice. Modern stereotactic ablative procedures as thermal or radiofrequency ablation, and particularly radiosurgery (e.g., Gamma Knife) are much safer than the historical procedures, so that a re-evaluation of this technique is required. The different approaches of modern psychiatric neurosurgery refer to different paradigms: microsurgical ablative procedures is based on the paradigm 'quick fix,' radiosurgery on the paradigm 'minimal-invasiveness,' and DBS on the paradigm 'adjustability.' From a mere medical perspective, none of the procedures is absolutely superior; rather, they have different profiles of advantages and disadvantages. Therefore, individual factors are crucial in decision-making, particularly the patients' social situation, individual preferences, and individual attitudes. The different approaches are not only rivals, but also enriching mutually. DBS is preferable for exploring new targets, which may become candidates for ablative microsurgery or radiosurgery.

  1. Combination of water-jet dissection and needle-knife as a hybrid knife simplifies endoscopic submucosal dissection.

    PubMed

    Lingenfelder, Tobias; Fischer, Klaus; Sold, Moritz G; Post, Stefan; Enderle, Markus D; Kaehler, Georg F B A

    2009-07-01

    The safety and efficacy of endoscopic submucosal dissection (ESD) is very dependent on an effective injection beneath the submucosal lamina and on a controlled cutting technique. After our study group demonstrated the efficacy of the HydroJet in needleless submucosal injections under various physical conditions to create a submucosal fluid cushion (Selective tissue elevation by pressure = STEP technique), the next step was to develop a new instrument to combine the capabilities of an IT-Knife with a high-pressure water-jet in a single instrument. In this experimental study, we compared this new instrument with a standard ESD technique. Twelve gastric ESD were performed in six pigs under endotracheal anesthesia. Square areas measuring 4-cm x 4-cm were marked out on the anterior and posterior wall in the corpus-antrum transition region. The HybridKnife was used as an standard needle knife with insulated tip (i.e., the submucosal injection was performed with an injection needle and only the radiofrequency (RF) part of the HybridKnife was used for cutting (conventional technique)) or the HybridKnife was used in all the individual stages of the ESD, making use of the HybridKnife's combined functions (HybridKnife technique). The size of the resected specimens, the operating time, the frequency with which instruments were changed, the number of bleeding episodes, and the number of injuries to the gastric wall together with the subjective overall assessment of the intervention by the operating physician were recorded. The resected specimens were the same size, with average sizes of 16.96 cm(2) and 15.85 cm(2) resp (p = 0.8125). Bleeding episodes have been less frequent in the HybridKnife group (2.83 vs. 3.5; p = 0.5625). The standard knife caused more injuries to the lamina muscularis propria (0.17 vs. 1.33; p = 0.0313). The operating times had a tendency to be shorter with the HybridKnife technique (47.18 vs. 58.32 minute; p = 0.0313). The combination of a needle-knife

  2. Efficacy, safety and outcome of frameless image-guided robotic radiosurgery for brain metastases after whole brain radiotherapy.

    PubMed

    Lohkamp, Laura-Nanna; Vajkoczy, Peter; Budach, Volker; Kufeld, Markus

    2018-05-01

    Estimating efficacy, safety and outcome of frameless image-guided robotic radiosurgery for the treatment of recurrent brain metastases after whole brain radiotherapy (WBRT). We performed a retrospective single-center analysis including patients with recurrent brain metastases after WBRT, who have been treated with single session radiosurgery, using the CyberKnife® Radiosurgery System (CKRS) (Accuray Inc., CA) between 2011 and 2016. The primary end point was local tumor control, whereas secondary end points were distant tumor control, treatment-related toxicity and overall survival. 36 patients with 140 recurrent brain metastases underwent 46 single session CKRS treatments. Twenty one patients had multiple brain metastases (58%). The mean interval between WBRT and CKRS accounted for 2 years (range 0.2-7 years). The median number of treated metastases per treatment session was five (range 1-12) with a tumor volume of 1.26 ccm (mean) and a median tumor dose of 18 Gy prescribed to the 70% isodose line. Two patients experienced local tumor recurrence within the 1st year after treatment and 13 patients (36%) developed novel brain metastases. Nine of these patients underwent additional one to three CKRS treatments. Eight patients (22.2%) showed treatment-related radiation reactions on MRI, three with clinical symptoms. Median overall survival was 19 months after CKRS. The actuarial 1-year local control rate was 94.2%. CKRS has proven to be locally effective and safe due to high local tumor control rates and low toxicity. Thus CKRS offers a reliable salvage treatment option for recurrent brain metastases after WBRT.

  3. [Design and application of silver needle-knife].

    PubMed

    Sun, Guodong; Shi, Bin; Zhang, Benwu; Xu, Haidong

    2015-04-01

    A silver needle-knife which has the dual function of silver needle and needle-knife is designed. The main components of this silver needle-knife are approximately 50% silver and approximately 50% nichrome. The silver needle-knife is composed of five parts, including needle-knife tail, spiral handle; steering handle, needle-knife body and needle-knife edge. It converges the advantages of needle-knife and silver needle, which can cut loose of diseased tissue and peel adhesion of lesions, but also be heated with moxa cone and thermal therapeutic instrument, and connect with electroacupuncture apparatus. It has the function of warming channel and removing coldness, dispelling wind and eliminating dampness, resolving spasm and relieving pain, dredging the channel and so on. Due to the spiral handle and the steering handle, the operation is easier, which reduces the blindness of cutting and increase the safety. It is mainly used for soft tissue injury, rheumatism and rheumatoid arthritis, as well as degenerative diseases of spine and joint, and it has obvious efficacy on some internal medical diseases.

  4. Time-resolved imaging of prompt-gamma rays for proton range verification using a knife-edge slit camera based on digital photon counters

    NASA Astrophysics Data System (ADS)

    Cambraia Lopes, Patricia; Clementel, Enrico; Crespo, Paulo; Henrotin, Sebastien; Huizenga, Jan; Janssens, Guillaume; Parodi, Katia; Prieels, Damien; Roellinghoff, Frauke; Smeets, Julien; Stichelbaut, Frederic; Schaart, Dennis R.

    2015-08-01

    Proton range monitoring may facilitate online adaptive proton therapy and improve treatment outcomes. Imaging of proton-induced prompt gamma (PG) rays using a knife-edge slit collimator is currently under investigation as a potential tool for real-time proton range monitoring. A major challenge in collimated PG imaging is the suppression of neutron-induced background counts. In this work, we present an initial performance test of two knife-edge slit camera prototypes based on arrays of digital photon counters (DPCs). PG profiles emitted from a PMMA target upon irradiation with a 160 MeV proton pencil beams (about 6.5   ×   109 protons delivered in total) were measured using detector modules equipped with four DPC arrays coupled to BGO or LYSO : Ce crystal matrices. The knife-edge slit collimator and detector module were placed at 15 cm and 30 cm from the beam axis, respectively, in all cases. The use of LYSO : Ce enabled time-of-flight (TOF) rejection of background events, by synchronizing the DPC readout electronics with the 106 MHz radiofrequency signal of the cyclotron. The signal-to-background (S/B) ratio of 1.6 obtained with a 1.5 ns TOF window and a 3 MeV-7 MeV energy window was about 3 times higher than that obtained with the same detector module without TOF discrimination and 2 times higher than the S/B ratio obtained with the BGO module. Even 1 mm shifts of the Bragg peak position translated into clear and consistent shifts of the PG profile if TOF discrimination was applied, for a total number of protons as low as about 6.5   ×   108 and a detector surface of 6.6 cm  ×  6.6 cm.

  5. In vivo dose measurement using TLDs and MOSFET dosimeters for cardiac radiosurgery.

    PubMed

    Gardner, Edward A; Sumanaweera, Thilaka S; Blanck, Oliver; Iwamura, Alyson K; Steel, James P; Dieterich, Sonja; Maguire, Patrick

    2012-05-10

    In vivo measurements were made of the dose delivered to animal models in an effort to develop a method for treating cardiac arrhythmia using radiation. This treatment would replace RF energy (currently used to create cardiac scar) with ionizing radiation. In the current study, the pulmonary vein ostia of animal models were irradiated with 6 MV X-rays in order to produce a scar that would block aberrant signals characteristic of atrial fibrillation. The CyberKnife radiosurgery system was used to deliver planned treatments of 20-35 Gy in a single fraction to four animals. The Synchrony system was used to track respiratory motion of the heart, while the contractile motion of the heart was untracked. The dose was measured on the epicardial surface near the right pulmonary vein and on the esophagus using surgically implanted TLD dosimeters, or in the coronary sinus using a MOSFET dosimeter placed using a catheter. The doses measured on the epicardium with TLDs averaged 5% less than predicted for those locations, while doses measured in the coronary sinus with the MOSFET sensor nearest the target averaged 6% less than the predicted dose. The measurements on the esophagus averaged 25% less than predicted. These results provide an indication of the accuracy with which the treatment planning methods accounted for the motion of the target, with its respiratory and cardiac components. This is the first report on the accuracy of CyberKnife dose delivery to cardiac targets.

  6. Clinical outcomes in patients with brain metastases from breast cancer treated with single-session radiosurgery or whole brain radiotherapy.

    PubMed

    Mix, Michael; Elmarzouky, Rania; O'Connor, Tracey; Plunkett, Robert; Prasad, Dheerendra

    2016-12-01

    OBJECTIVE Gamma Knife radiosurgery (GKRS) is used to treat brain metastases from breast cancer (BMB) as the sole treatment or in conjunction with tumor resection and/or whole brain radiotherapy (WBRT). This study evaluates outcomes in BMB based on treatment techniques and tumor biological features. METHODS The authors reviewed all patients treated with BMB between 2004 and 2014. Patients were identified from a prospectively collected radiosurgery database and institutional tumor registry; 214 patients were identified. Data were collected from aforementioned sources and supplemented with chart review where needed. Independent radiological review was performed for all available brain imaging in those treated with GKRS. Survival analyses are reported using Kaplan-Meier estimates. RESULTS During the 10-year study period, 214 patients with BMB were treated; 23% underwent GKRS alone, 46% underwent a combination of GKRS and WBRT, and 31% underwent WBRT alone. Median survival after diagnosis of BMB in those treated with GKRS alone was 21 months, and in those who received WBRT alone it was 3 months. In those treated with GKRS plus WBRT, no significant difference in median survival was observed between those receiving WBRT upfront or in a salvage setting following GKRS (19 months vs 14 months, p = 0.63). The median survival of patients with total metastatic tumor volume of ≤ 7 cm 3 versus > 7 cm 3 was 20 months vs 7 months (p < 0.001). Human epidermal growth factor receptor-2 (Her-2) positively impacted survival after diagnosis of BMB (19 months vs 12 months, p = 0.03). Estrogen receptor status did not influence survival after diagnosis of BMB. No difference was observed in survival after diagnosis of BMB based on receptor status in those who received WBRT alone. CONCLUSIONS In this single-institution series of BMB, the addition of WBRT to GKRS did not significantly influence survival, nor did the number of lesions treated with GKRS. Survival after the diagnosis of BMB was

  7. [Infraoccipital needle-knife for cervical vertigo].

    PubMed

    Li, Shaofang; Huang, Manhua; Lin, Zhuopeng; Chen, Xinze; Lin, Dongna; Lu, Peng; Lu, Qu

    2017-03-12

    To observe the clinical effect differences between infraoccipital needle-knife and massage for cervical vertigo. A total of 366 patients with cervical vertigo were randomly assigned into a needle-knife group (186 cases) and a massage group (180 cases). With cases dropping excluded, 183 cases in the needle-knife group and 176 cases in the massage group were included. Needle-knife was used at Fengchi (GB 20), infraoccipital ashi point, etc. in the needle-knife group. The treatment was given for one course, once three days, 5 times as one course. The traditional massage was applied in the massage group for one course, including systematic stroking, kneading, and the application of pressure and plucking, etc., once every two days and 7 times as one course. The dizziness handicap inventory (DHI) score was observed before and after treatment, as well as 3, 6, and 12 months after treatment. The effects were also evaluated. The total effective rate was 92.3% (169/183) in the needle-knife group, which was better than 85.2% (150/176) in the massage group ( P <0.05). Compared with those before treatment, the DHI scores at all the observation time points after treatment were improved in the two groups (all P <0.05), with better improvements after treatment as well as 3 and 6 months after treatment in the needle-knife group (all P <0.05). There was no significant difference in the improvement of DHI scores between the two groups 12 months after treatment ( P >0.05). The recurrence rate was 10.3% (12/117) in the needle-knife group, and it was 10.7% (11/103) in the massage group 12 months after treatment ( P >0.05). Infraoccipital needle-knife achieves apparent effect for cervical vertigo, which is superior to massage in short period.

  8. Analysis of volumetric response of pituitary adenomas receiving adjuvant CyberKnife stereotactic radiosurgery with the application of an exponential fitting model

    PubMed Central

    Yu, Yi-Lin; Yang, Yun-Ju; Lin, Chin; Hsieh, Chih-Chuan; Li, Chiao-Zhu; Feng, Shao-Wei; Tang, Chi-Tun; Chung, Tzu-Tsao; Ma, Hsin-I; Chen, Yuan-Hao; Ju, Da-Tong; Hueng, Dueng-Yuan

    2017-01-01

    Abstract Tumor control rates of pituitary adenomas (PAs) receiving adjuvant CyberKnife stereotactic radiosurgery (CK SRS) are high. However, there is currently no uniform way to estimate the time course of the disease. The aim of this study was to analyze the volumetric responses of PAs after CK SRS and investigate the application of an exponential decay model in calculating an accurate time course and estimation of the eventual outcome. A retrospective review of 34 patients with PAs who received adjuvant CK SRS between 2006 and 2013 was performed. Tumor volume was calculated using the planimetric method. The percent change in tumor volume and tumor volume rate of change were compared at median 4-, 10-, 20-, and 36-month intervals. Tumor responses were classified as: progression for >15% volume increase, regression for ≤15% decrease, and stabilization for ±15% of the baseline volume at the time of last follow-up. For each patient, the volumetric change versus time was fitted with an exponential model. The overall tumor control rate was 94.1% in the 36-month (range 18–87 months) follow-up period (mean volume change of −43.3%). Volume regression (mean decrease of −50.5%) was demonstrated in 27 (79%) patients, tumor stabilization (mean change of −3.7%) in 5 (15%) patients, and tumor progression (mean increase of 28.1%) in 2 (6%) patients (P = 0.001). Tumors that eventually regressed or stabilized had a temporary volume increase of 1.07% and 41.5% at 4 months after CK SRS, respectively (P = 0.017). The tumor volume estimated using the exponential fitting equation demonstrated high positive correlation with the actual volume calculated by magnetic resonance imaging (MRI) as tested by Pearson correlation coefficient (0.9). Transient progression of PAs post-CK SRS was seen in 62.5% of the patients receiving CK SRS, and it was not predictive of eventual volume regression or progression. A three-point exponential model is of potential predictive value

  9. Analysis of volumetric response of pituitary adenomas receiving adjuvant CyberKnife stereotactic radiosurgery with the application of an exponential fitting model.

    PubMed

    Yu, Yi-Lin; Yang, Yun-Ju; Lin, Chin; Hsieh, Chih-Chuan; Li, Chiao-Zhu; Feng, Shao-Wei; Tang, Chi-Tun; Chung, Tzu-Tsao; Ma, Hsin-I; Chen, Yuan-Hao; Ju, Da-Tong; Hueng, Dueng-Yuan

    2017-01-01

    Tumor control rates of pituitary adenomas (PAs) receiving adjuvant CyberKnife stereotactic radiosurgery (CK SRS) are high. However, there is currently no uniform way to estimate the time course of the disease. The aim of this study was to analyze the volumetric responses of PAs after CK SRS and investigate the application of an exponential decay model in calculating an accurate time course and estimation of the eventual outcome.A retrospective review of 34 patients with PAs who received adjuvant CK SRS between 2006 and 2013 was performed. Tumor volume was calculated using the planimetric method. The percent change in tumor volume and tumor volume rate of change were compared at median 4-, 10-, 20-, and 36-month intervals. Tumor responses were classified as: progression for >15% volume increase, regression for ≤15% decrease, and stabilization for ±15% of the baseline volume at the time of last follow-up. For each patient, the volumetric change versus time was fitted with an exponential model.The overall tumor control rate was 94.1% in the 36-month (range 18-87 months) follow-up period (mean volume change of -43.3%). Volume regression (mean decrease of -50.5%) was demonstrated in 27 (79%) patients, tumor stabilization (mean change of -3.7%) in 5 (15%) patients, and tumor progression (mean increase of 28.1%) in 2 (6%) patients (P = 0.001). Tumors that eventually regressed or stabilized had a temporary volume increase of 1.07% and 41.5% at 4 months after CK SRS, respectively (P = 0.017). The tumor volume estimated using the exponential fitting equation demonstrated high positive correlation with the actual volume calculated by magnetic resonance imaging (MRI) as tested by Pearson correlation coefficient (0.9).Transient progression of PAs post-CK SRS was seen in 62.5% of the patients receiving CK SRS, and it was not predictive of eventual volume regression or progression. A three-point exponential model is of potential predictive value according to relative

  10. Sharpening peripheral dose gradient via beam number enhancement from patient head tilt for stereotactic brain radiosurgery

    NASA Astrophysics Data System (ADS)

    Chiu, Joshua; Pierce, Marlon; Braunstein, Steve E.; Theodosopoulos, Philip V.; McDermott, Michael W.; Sneed, Penny K.; Ma, Lijun

    2016-10-01

    Sharp dose fall-off is the hallmark of brain radiosurgery for the purpose of delivering high dose radiation to the target while minimizing peripheral dose to regional normal brain tissue. In this study, a technique was developed to enhance the peripheral dose gradient by magnifying the total number of beams focused toward each isocenter through pre-programmed patient head tilting. This technique was tested in clinical settings on a dedicated brain radiosurgical system (GKPFX, Gamma Knife Perfexion, Elekta Oncology) by comparing dosimetry as well as delivery efficiency for 20 radiosurgical cases previously treated with the system. The 3-fold beam number enhancement (BNE) treatment plans were found to produce nearly identical target volume coverage (absolute value  <  0.5%, P  >  0.2) and dose conformity (BNE CI  =  1.41  ±  0.22 versus 1.41  ±  0.11, P  >  0.99) as the original treatment plans. The total beam-on time for the 3-fold BNE treatment plans were also found to be comparable (<0.5 min or 2%) with those of the original treatment plans for all the cases. However, BNE treatment plans significantly improved the mean gradient index (BNE GI  =  2.94  ±  0.27 versus original GI  =  2.98  ±  0.28 P  <  0.0001) and low-level isodose volumes, e.g. 20-50% prescribed isodose volumes, by 1.7%-3.9% (P  <  0.03). With further 4-5-fold increase in the total number of beams, the absolute gradient index can decrease by as much as  -0.5 in absolute value or  -20% for a treatment. In conclusion, BNE via patient head tilt has been demonstrated to be a clinically suitable and efficient technique for physically sharpening the peripheral dose gradient for brain radiosurgery. This work was presented in part at the 2015 ISRS Congress in Yokohama Japan.

  11. Souvenir knife: a retained transcranial knife blade.

    PubMed

    Davis, Neil L; Kahana, Tzipi; Hiss, Jehuda

    2004-09-01

    Upon necroscopic examination of a homeless male found comatose in the street and pronounced dead at a medical center 12 hours later, a sharp tip of a knife lodged in the right parietal region of his skull was incidentally discovered. The blade transected the diploe and penetrated the cerebral cortex. Subsequent police investigation revealed that this was the remnant of a stabbing attempt on his life several months prior to his death. The cause of death was determined to be unrelated to the metallic blade fragment, thus making it a truly incidental and rare finding of a "souvenir knife." Nevertheless, since the injury sustained in the stabbing was potentially life threatening, the investigation into that assault was reopened.A case report is presented, along with a brief review of the literature on "souvenir objects."

  12. Acrogigantism and facial asymmetry: McCune-Albright syndrome.

    PubMed

    Subbiah, Sridhar; Palikhe, Gaurav; Bhadada, Sanjay Kumar; Mukherjee, Kanchan Kumar; Bhansali, Anil

    2011-01-01

    McCune-Albright syndrome (MAS) is characterized by a triad of poly/monoostotic fibrous dysplasia, café-au-lait macules and hyperfunctioning endocrinopathies. Association of MAS with GH excess is rare, and in most of the instances somatotropinoma has not been documented. Treatment of patients of MAS with acromegaly is difficult because of thickened calvarium and dysplastic skull bone. We report a 17-year-old girl, who presented with cranio-facial fibrous dysplasia, café-au-lait macules and also had acromegaly due to pituitary macroadenoma, and treated with gamma knife radiosurgery.

  13. Asymptomatic solitary cerebral metastasis from papillary carcinoma thyroid: 131I SPECT/CT for accurate staging.

    PubMed

    Jain, Tarun Kumar; Karunanithi, Sellam; Sharma, Punit; Vijay, Maneesh Kumar; Ballal, Sanjana; Bal, Chandrasekhar

    2014-11-01

    Isolated asymptomatic brain metastasis in papillary carcinoma thyroid (PCT) is extremely rare. We here present such a case of a 48-year-old woman with PCT. SPECT/CT localized the 131I radiotracer concentration seen on whole-body scan in this patient to the right posterior parietal cortex, suggesting brain metastasis. Contrast-enhanced MRI and 18F-FDG PET/CT confirmed the diagnosis and the patient was taken for gamma-knife radiosurgery. 131I SPECT/CT in this case accurately restaged the patient by detecting asymptomatic isolated brain metastasis and correctly directed the management strategy.

  14. Transcatheter arterial chemoembolization (TACE) combined with γ-knife compared to TACE or γ-knife alone for hepatocellular carcinoma.

    PubMed

    Cai, Yeyu; Chang, Qian; Xiao, Enhua; Shang, Quan-Liang; Chen, Zhu

    2018-06-01

    To compare the clinical efficacies and adverse reactions between transcatheter arterial chemoembolization (TACE), γ-ray 3-dimensional fractionated stereotactic conformal radiotherapy (FSCR), and TACE combined with FSCR for primary hepatocellular carcinoma.The study was approved by the Institutional Review Board, and informed consent was waived due to the retrospective study design. About 121 patients met the inclusion criteria and were included in this study, from March 2008 to January 2010, in the Second Xiangya Hospital. Forty-six patients underwent TACE alone, 36 patients underwent γ-knife alone, and 39 were treated by γ-knife combined with TACE. Short-term effects, overall survival rates, adverse reactions, and survival times were compared between the 3 treatment groups.Short-term effects were observed in 41.3% of the TACE group, 33.3% of the γ-knife group, and 64.1% of the TACE combined γ-knife group (P = .020). Overall survival rates at 6,12, 18, and 24 months were 50%, 34.8%, 28.3%, and 21.7% for the TACE group, 36.1%, 30.6%, 16.7%, and 11.1% for γ-knife group, and 84.6%, 71.8%, 61.5%, and 30.8% for TACE combined γ-knife group, respectively. The differences in the overall survival rates at 6, 12, and 18 months between the 3 groups were statistically significant (P = 0), but the overall survival rates at 24 months in the 3 groups were not significantly different (P = .117). The median survival time was 7 months for the TACE group, 3 months for the γ-knife group, and 20 months for the TACE combined γ-knife group (P = 0). There were statistically significant differences (P = .010) of leukopenia between the 3 groups, and no statistically significant differences of (P > .05) thrombocytopenia, anemia, nausea, vomiting, and liver function lesions.TACE combined with γ-knife for primary hepatocellular carcinoma is superior to TACE or γ-knife alone in short-term and long-term effects. This procedure is a mild, safe, and effective

  15. Dedicated linear accelerator radiosurgery for trigeminal neuralgia: a single-center experience in 179 patients with varied dose prescriptions and treatment plans.

    PubMed

    Smith, Zachary A; Gorgulho, Alessandra A; Bezrukiy, Nikita; McArthur, David; Agazaryan, Nzhde; Selch, Michael T; De Salles, Antonio A F

    2011-09-01

    Dedicated linear accelerator radiosurgery (D-LINAC) has become an important treatment for trigeminal neuralgia (TN). Although the use of gamma knife continues to be established, few large series exist using D-LINAC. The authors describe their results, comparing the effects of varied target and dose regimens. Between August 1995 and January 2008, 179 patients were treated with D-LINAC radiosurgery. Ten patients (5.58%) had no clinical follow-up. The median age was 74.0 years (range, 32-90 years). A total of 39 patients had secondary or atypical pain, and 130 had idiopathic TN. Initially, 28 patients received doses between 70 and 85 Gy, with the 30% isodose line (IDL) touching the brainstem. Then, using 90 Gy, 82 consecutive patients were treated with a 30% IDL and 59 patients with a 50% IDL tangential to the pons. Of 169 patients, 134 (79.3%) experienced significant relief at a mean of 28.8 months (range, 5-142 months). Average time to relief was 1.92 months (range, immediate to 6 months). A total of 31 patients (19.0%) had recurrent pain at 13.5 months. Of 87 patients with idiopathic TN without prior procedures, 79 (90.8%) had initial relief. Among 28 patients treated with 70 Gy and 30% IDL, 18 patients (64.3%) had significant relief, and 10 (35.7%) had numbness. Of the patients with 90 Gy and 30% IDL at the brainstem, 59 (79.0%) had significant relief and 48.9% had numbness. Among 59 consecutive patients with similar dose but the 50% isodoseline at the brainstem, 49 patients (88.0%) had excellent/good relief. Numbness, averaging 2.49 on a subjective scale of 1 to 5, was experienced by 49.7% of the patients, Increased radiation dose and volume of brainstem irradiation may improve clinical outcomes with the trade-off of trigeminal dysfunction. Further study of the implications of dose and target are needed to optimize outcomes and to minimize complications. Published by Elsevier Inc.

  16. Dedicated Linear Accelerator Radiosurgery for Trigeminal Neuralgia: A Single-Center Experience in 179 Patients With Varied Dose Prescriptions and Treatment Plans

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Smith, Zachary A.; Gorgulho, Alessandra A.; Bezrukiy, Nikita

    2011-09-01

    Purpose: Dedicated linear accelerator radiosurgery (D-LINAC) has become an important treatment for trigeminal neuralgia (TN). Although the use of gamma knife continues to be established, few large series exist using D-LINAC. The authors describe their results, comparing the effects of varied target and dose regimens. Methods and Materials: Between August 1995 and January 2008, 179 patients were treated with D-LINAC radiosurgery. Ten patients (5.58%) had no clinical follow-up. The median age was 74.0 years (range, 32-90 years). A total of 39 patients had secondary or atypical pain, and 130 had idiopathic TN. Initially, 28 patients received doses between 70 andmore » 85 Gy, with the 30% isodose line (IDL) touching the brainstem. Then, using 90 Gy, 82 consecutive patients were treated with a 30% IDL and 59 patients with a 50% IDL tangential to the pons. Results: Of 169 patients, 134 (79.3%) experienced significant relief at a mean of 28.8 months (range, 5-142 months). Average time to relief was 1.92 months (range, immediate to 6 months). A total of 31 patients (19.0%) had recurrent pain at 13.5 months. Of 87 patients with idiopathic TN without prior procedures, 79 (90.8%) had initial relief. Among 28 patients treated with 70 Gy and 30% IDL, 18 patients (64.3%) had significant relief, and 10 (35.7%) had numbness. Of the patients with 90 Gy and 30% IDL at the brainstem, 59 (79.0%) had significant relief and 48.9% had numbness. Among 59 consecutive patients with similar dose but the 50% isodoseline at the brainstem, 49 patients (88.0%) had excellent/good relief. Numbness, averaging 2.49 on a subjective scale of 1 to 5, was experienced by 49.7% of the patients, Conclusions: Increased radiation dose and volume of brainstem irradiation may improve clinical outcomes with the trade-off of trigeminal dysfunction. Further study of the implications of dose and target are needed to optimize outcomes and to minimize complications.« less

  17. In vivo dose measurement using TLDs and MOSFET dosimeters for cardiac radiosurgery

    PubMed Central

    Sumanaweera, Thilaka S.; Blanck, Oliver; Iwamura, Alyson K.; Steel, James P.; Dieterich, Sonja; Maguire, Patrick

    2012-01-01

    In vivo measurements were made of the dose delivered to animal models in an effort to develop a method for treating cardiac arrhythmia using radiation. This treatment would replace RF energy (currently used to create cardiac scar) with ionizing radiation. In the current study, the pulmonary vein ostia of animal models were irradiated with 6 MV X‐rays in order to produce a scar that would block aberrant signals characteristic of atrial fibrillation. The CyberKnife radiosurgery system was used to deliver planned treatments of 20–35 Gy in a single fraction to four animals. The Synchrony system was used to track respiratory motion of the heart, while the contractile motion of the heart was untracked. The dose was measured on the epicardial surface near the right pulmonary vein and on the esophagus using surgically implanted TLD dosimeters, or in the coronary sinus using a MOSFET dosimeter placed using a catheter. The doses measured on the epicardium with TLDs averaged 5% less than predicted for those locations, while doses measured in the coronary sinus with the MOSFET sensor nearest the target averaged 6% less than the predicted dose. The measurements on the esophagus averaged 25% less than predicted. These results provide an indication of the accuracy with which the treatment planning methods accounted for the motion of the target, with its respiratory and cardiac components. This is the first report on the accuracy of CyberKnife dose delivery to cardiac targets. PACS numbers: 87.53.Ly, 87.53.Bn PMID:22584173

  18. Complications following linear accelerator based stereotactic radiation for cerebral arteriovenous malformations.

    PubMed

    Skjøth-Rasmussen, Jane; Roed, Henrik; Ohlhues, Lars; Jespersen, Bo; Juhler, Marianne

    2010-06-01

    Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large gamma knife center, the risk profile at Linac departments could be different from the reported experience. Prescribed radiation doses are dependent on AVM volume. This study details results from a medium sized Linac department center focusing on risk profiles. A database was searched for all patients with AVMs. We included 50 consecutive patients with a minimum of 24 months follow-up (24-51 months). AVM occlusion was verified in 78% of patients (39/50). AVM occlusion without new deficits (excellent outcome) was obtained in 44%. Good or fair outcome (AVM occlusion with mild or moderate new deficits) was seen in 30%. Severe complications after AVM occlusion occurred in 4% with a median interval of 15 months after treatment (range, 1-26 months). We applied an AVM grading score developed at the Mayo Clinic to predict probable outcome after radiosurgery in a large patient population treated with Gamma knife. A cutoff above and below a score of 1.5 could not discriminate between the likelihood of having an excellent outcome (approximately 45%). The chance of having an excellent or good outcome was slightly higher in patients with an AVM score below 1.5 (64% vs. 57%). Copyright 2010 Elsevier Inc. All rights reserved.

  19. Validation of a pretreatment delivery quality assurance method for the CyberKnife Synchrony system.

    PubMed

    Mastella, E; Vigorito, S; Rondi, E; Piperno, G; Ferrari, A; Strata, E; Rozza, D; Jereczek-Fossa, B A; Cattani, F

    2016-08-01

    To evaluate the geometric and dosimetric accuracies of the CyberKnife Synchrony respiratory tracking system (RTS) and to validate a method for pretreatment patient-specific delivery quality assurance (DQA). An EasyCube phantom was mounted on the ExacTrac gating phantom, which can move along the superior-inferior (SI) axis of a patient to simulate a moving target. The authors compared dynamic and static measurements. For each case, a Gafchromic EBT3 film was positioned between two slabs of the EasyCube, while a PinPoint ionization chamber was placed in the appropriate space. There were three steps to their evaluation: (1) the field size, the penumbra, and the symmetry of six secondary collimators were measured along the two main orthogonal axes. Dynamic measurements with deliberately simulated errors were also taken. (2) The delivered dose distributions (from step 1) were compared with the planned ones, using the gamma analysis method. The local gamma passing rates were evaluated using three acceptance criteria: 3% local dose difference (LDD)/3 mm, 2%LDD/2 mm, and 3%LDD/1 mm. (3) The DQA plans for six clinical patients were irradiated in different dynamic conditions, to give a total of 19 cases. The measured and planned dose distributions were evaluated with the same gamma-index criteria used in step 2 and the measured chamber doses were compared with the planned mean doses in the sensitive volume of the chamber. (1) A very slight enlargement of the field size and of the penumbra was observed in the SI direction (on average <1 mm), in line with the overall average CyberKnife system error for tracking treatments. (2) Comparison between the planned and the correctly delivered dose distributions confirmed the dosimetric accuracy of the RTS for simple plans. The multicriteria gamma analysis was able to detect the simulated errors, proving the robustness of their method of analysis. (3) All of the DQA clinical plans passed the tests, both in static and dynamic conditions

  20. Radiosurgery to the Postoperative Surgical Cavity: Who Needs Evidence?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roberge, David, E-mail: david.roberge@mcgill.ca; Department of Radiation Oncology, Centre Hospitalier de l'Universite de Montreal, Montreal, QC; Parney, Ian

    2012-06-01

    There is a growing interest in adjuvant radiosurgery after resection of hematogenous brain metastases. This is exemplified by the approximately 1000 cases reported in mainly retrospective series. These cases fall into four paradigms: adjuvant radiosurgery as an alternative to whole-brain radiotherapy (WBRT), radiosurgery neoadjuvant to the surgical resection, radiosurgery as an intensification of adjuvant WBRT, and adjuvant radiosurgery for patients having failed prior WBRT. These procedures seem well tolerated, with an approximate 5% risk of radiation necrosis. Although crude local control rates for each strategy seem improved over surgery alone, multiple biases make comparisons with standard WBRT difficult without prospectivemore » data. Because evidence lags behind clinical practice, an upcoming intergroup trial will aim to clarify the value of the most common tumor bed radiosurgery strategy by randomizing oligometastatic patients between adjuvant WBRT and adjuvant radiosurgery.« less

  1. Histology-Stratified Tumor Control and Patient Survival After Stereotactic Radiosurgery for Pineal Region Tumors: A Report From the International Gamma Knife Research Foundation.

    PubMed

    Iorio-Morin, Christian; Kano, Hideyuki; Huang, Marshall; Lunsford, L Dade; Simonová, Gabriela; Liscak, Roman; Cohen-Inbar, Or; Sheehan, Jason; Lee, Cheng-Chia; Wu, Hsiu-Mei; Mathieu, David

    2017-11-01

    Pineal region tumors represent a rare and histologically diverse group of lesions. Few studies are available to guide management and the outcomes after stereotactic radiosurgery (SRS). Patients who underwent SRS for a pineal region tumor and for whom at least 6 months of imaging follow-up was available were retrospectively assessed in 5 centers. Data were collected from the medical record and histology level analyses were performed, including actuarial tumor control and survival analyses. A total of 70 patients were treated between 1989 and 2014 with a median follow-up of 47 months. Diagnoses were pineocytoma (37%), pineoblastoma (19%), pineal parenchymal tumor of intermediate differentiation (10%), papillary tumor of the pineal region (9%), germinoma (7%), teratoma (3%), embryonal carcinoma (1%), and unknown (14%). Median prescription dose was 15 Gy at the 50% isodose line. Actuarial local control and survival rates were 81% and 76% at 20 years for pineocytoma, 50% and 56% at 5 years for pineal parenchymal tumor of intermediate differentiation, 27% and 48% at 5 years for pineoblastoma, 33% and 100% at 5 years for papillary tumor of the pineal region, 80% and 80% at 20 years for germinoma, and 61% and 67% at 5 years for tumors of unknown histology. New focal neurological deficit, Parinaud syndrome, and hydrocephalus occurred in 9%, 7%, and 3% of cases, respectively. SRS is a safe modality for the management of pineal region tumors. Its specific role is highly dependent on tumor histology. As such, all efforts should be made to obtain a reliable histologic diagnosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Film-based delivery quality assurance for robotic radiosurgery: Commissioning and validation.

    PubMed

    Blanck, Oliver; Masi, Laura; Damme, Marie-Christin; Hildebrandt, Guido; Dunst, Jürgen; Siebert, Frank-Andre; Poppinga, Daniela; Poppe, Björn

    2015-07-01

    Robotic radiosurgery demands comprehensive delivery quality assurance (DQA), but guidelines for commissioning of the DQA method is missing. We investigated the stability and sensitivity of our film-based DQA method with various test scenarios and routine patient plans. We also investigated the applicability of tight distance-to-agreement (DTA) Gamma-Index criteria. We used radiochromic films with multichannel film dosimetry and re-calibration and our analysis was performed in four steps: 1) Film-to-plan registration, 2) Standard Gamma-Index criteria evaluation (local-pixel-dose-difference ≤2%, distance-to-agreement ≤2 mm, pass-rate ≥90%), 3) Dose distribution shift until maximum pass-rate (Maxγ) was found (shift acceptance <1 mm), and 4) Final evaluation with tight DTA criteria (≤1 mm). Test scenarios consisted of purposefully introduced phantom misalignments, dose miscalibrations, and undelivered MU. Initial method evaluation was done on 30 clinical plans. Our method showed similar sensitivity compared to the standard End-2-End-Test and incorporated an estimate of global system offsets in the analysis. The simulated errors (phantom shifts, global robot misalignment, undelivered MU) were detected by our method while standard Gamma-Index criteria often did not reveal these deviations. Dose miscalibration was not detected by film alone, hence simultaneous ion-chamber measurement for film calibration is strongly recommended. 83% of the clinical patient plans were within our tight DTA tolerances. Our presented methods provide additional measurements and quality references for film-based DQA enabling more sensitive error detection. We provided various test scenarios for commissioning of robotic radiosurgery DQA and demonstrated the necessity to use tight DTA criteria. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  3. The Knife Machine. Module 15.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the knife machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers one topic: performing special operations on the knife machine (a single needle or multi-needle machine which sews and cuts at the same time). These components are provided: an introduction, directions, an objective,…

  4. TH-CD-BRA-09: Towards Absolute Dose Measurement in MRI-Linac and Gamma-Knife: Design and Construction of An MR-Compatible Water Calorimeter

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Entezari, N; Sarfehnia, A; Renaud, J

    Purpose: The purpose of this work is to design and optimize a portable Water Calorimeter (WC) for use in a commercial MRI-linac and Gamma-knife in addition to conventional radiotherapy linacs. Water calorimeters determine absorbed dose to water at a point by measuring radiation-induced temperature rise of the volume (the two are related by the medium specific heat capacity). In this formalism, one important correction factor is heat transfer correction k-ht. It compensates for heat gain/loss due to conductive and convective effects, and is numerically calculated as ratio of temperature rise in the absence of heat loss to that in themore » presence of heat loss. Operating at 4°C ensures convection is minimal. Methods: A commercial finite element software was used to evaluate several WC designs with different insulation materials and thicknesses; channels allowing coolant to travel around WC (to sustain WC at 4°C) were modeled, and worst-case scenario variation in the temperature of the coolant was simulated for optimization purposes (2.6 mK/s). Additionally, several calorimeter vessel design parameters (front/back glass thickness/separation, diameter) were also simulated and optimized. Optimization is based on minimizing long term calorimeter drift (24h) as well as variation and magnitude of k-ht. Results: The final selected WC design reached a modest drift of 11µK/s after 15h for the worst-case coolant temperature variation. This design consists of coolant channels being encompassed on both sides by cryogel insulation. For the MRI-linac beam, glass thickness plays the largest effect on k-ht with variation of upto 0.6% in the first run for thicknesses ranging between 0.5–1.7mm. Subsequent runs vary only within 0.1% with glass thickness. Other factors such as vessel radius and top/bottom glass separation have sub 0.1% effects on k-ht. Conclusion: An MR-safe 4°C stagnant WC appropriate for dosimetry in MRI-linac and Gamma-Knife was designed, optimized, and

  5. 21 CFR 886.4230 - Ophthalmic knife test drum.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ophthalmic knife test drum. 886.4230 Section 886...) MEDICAL DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4230 Ophthalmic knife test drum. (a) Identification. An ophthalmic knife test drum is a device intended to test the keenness of ophthalmic surgical...

  6. Gamma Knife surgery for arteriovenous malformations in the brain: integration of time-resolved contrast-enhanced magnetic resonance angiography into dosimetry planning. Technical note.

    PubMed

    Taschner, Christian A; Le Thuc, Vianney; Reyns, Nicolas; Gieseke, Juergen; Gauvrit, Jean-Yves; Pruvo, Jean-Pierre; Leclerc, Xavier

    2007-10-01

    The aim of this study was to develop an algorithm for the integration of time-resolved contrast-enhanced magnetic resonance (MR) angiography into dosimetry planning for Gamma Knife surgery (GKS) of arteriovenous malformations (AVMs) in the brain. Twelve patients harboring brain AVMs referred for GKS underwent intraarterial digital subtraction (DS) angiography and time-resolved MR angiography while wearing an externally applied cranial stereotactic frame. Time-resolved MR angiography was performed on a 1.5-tesla MR unit (Achieva, Philips Medical Systems) using contrast-enhanced 3D fast field echo sequencing with stochastic central k-space ordering. Postprocessing with interactive data language (Research Systems, Inc.) produced hybrid data sets containing dynamic angiographic information and the MR markers necessary for stereotactic transformation. Image files were sent to the Leksell GammaPlan system (Elekta) for dosimetry planning. Stereotactic transformation of the hybrid data sets containing the time-resolved MR angiography information with automatic detection of the MR markers was possible in all 12 cases. The stereotactic coordinates of vascular structures predefined from time-resolved MR angiography matched with DS angiography data in all cases. In 10 patients dosimetry planning could be performed based on time-resolved MR angiography data. In two patients, time-resolved MR angiography data alone were considered insufficient. The target volumes showed a notable shift of centers between modalities. Integration of time-resolved MR angiography data into the Leksell GammaPlan system for patients with brain AVMs is feasible. The proposed algorithm seems concise and sufficiently robust for clinical application. The quality of the time-resolved MR angiography sequencing needs further improvement.

  7. Cone-beam CT image contrast and attenuation-map linearity improvement (CALI) for brain stereotactic radiosurgery procedures

    NASA Astrophysics Data System (ADS)

    Hashemi, Sayed Masoud; Lee, Young; Eriksson, Markus; Nordström, Hâkan; Mainprize, James; Grouza, Vladimir; Huynh, Christopher; Sahgal, Arjun; Song, William Y.; Ruschin, Mark

    2017-03-01

    A Contrast and Attenuation-map (CT-number) Linearity Improvement (CALI) framework is proposed for cone-beam CT (CBCT) images used for brain stereotactic radiosurgery (SRS). The proposed framework is used together with our high spatial resolution iterative reconstruction algorithm and is tailored for the Leksell Gamma Knife ICON (Elekta, Stockholm, Sweden). The incorporated CBCT system in ICON facilitates frameless SRS planning and treatment delivery. The ICON employs a half-cone geometry to accommodate the existing treatment couch. This geometry increases the amount of artifacts and together with other physical imperfections causes image inhomogeneity and contrast reduction. Our proposed framework includes a preprocessing step, involving a shading and beam-hardening artifact correction, and a post-processing step to correct the dome/capping artifact caused by the spatial variations in x-ray energy generated by bowtie-filter. Our shading correction algorithm relies solely on the acquired projection images (i.e. no prior information required) and utilizes filtered-back-projection (FBP) reconstructed images to generate a segmented bone and soft-tissue map. Ideal projections are estimated from the segmented images and a smoothed version of the difference between the ideal and measured projections is used in correction. The proposed beam-hardening and dome artifact corrections are segmentation free. The CALI was tested on CatPhan, as well as patient images acquired on the ICON system. The resulting clinical brain images show substantial improvements in soft contrast visibility, revealing structures such as ventricles and lesions which were otherwise un-detectable in FBP-reconstructed images. The linearity of the reconstructed attenuation-map was also improved, resulting in more accurate CT#.

  8. Adaptation and validation of a commercial head phantom for cranial radiosurgery dosimetry end-to-end audit.

    PubMed

    Dimitriadis, Alexis; Palmer, Antony L; Thomas, Russell A S; Nisbet, Andrew; Clark, Catharine H

    2017-06-01

    To adapt and validate an anthropomorphic head phantom for use in a cranial radiosurgery audit. Two bespoke inserts were produced for the phantom: one for providing the target and organ at risk for delineation and the other for performing dose measurements. The inserts were tested to assess their positional accuracy. A basic treatment plan dose verification with an ionization chamber was performed to establish a baseline accuracy for the phantom and beam model. The phantom and inserts were then used to perform dose verification measurements of a radiosurgery plan. The dose was measured with alanine pellets, EBT extended dose film and a plastic scintillation detector (PSD). Both inserts showed reproducible positioning (±0.5 mm) and good positional agreement between them (±0.6 mm). The basic treatment plan measurements showed agreement to the treatment planning system (TPS) within 0.5%. Repeated film measurements showed consistent gamma passing rates with good agreement to the TPS. For 2%-2 mm global gamma, the mean passing rate was 96.7% and the variation in passing rates did not exceed 2.1%. The alanine pellets and PSD showed good agreement with the TPS (-0.1% and 0.3% dose difference in the target) and good agreement with each other (within 1%). The adaptations to the phantom showed acceptable accuracies. The presence of alanine and PSD do not affect film measurements significantly, enabling simultaneous measurements by all three detectors. Advances in knowledge: A novel method for thorough end-to-end test of radiosurgery, with capability to incorporate all steps of the clinical pathway in a time-efficient and reproducible manner, suitable for a national audit.

  9. Gamma Knife surgery in patients harboring orbital cavernous hemangiomas that were diagnosed on the basis of imaging findings.

    PubMed

    Liu, Xiaomin; Xu, Desheng; Zhang, Yipei; Liu, Dong; Song, Guoxiang

    2010-12-01

    This study was undertaken to evaluate clinical outcomes and tumor control in patients harboring orbital cavernous hemangiomas (OCHs) that had been diagnosed based on findings of imaging studies and treated by Gamma Knife surgery (GKS). Between 1995 and 2008, 23 patients harboring OCHs that had been diagnosed on the basis of imaging findings were treated using GKS; complete follow-up data are available in all cases. The median treatment volume was 1.5 cm³ (range 0.15-10.10 cm³), the median tumor margin dose was 15 Gy (range 12-20 Gy), and the median follow-up period was 12 months (range 6-120 months). A decrease in tumor size was found in 20 patients, and no tumor progression was observed after GKS. Eleven of 14 patients whose visual function had been adversely affected prior to treatment had improved visual acuity at the last assessment. Side effects of the procedure included orbital pain in 3 patients and chemosis in 2 patients. In this preliminary experience, GKS proved to be an effective treatment for OCHs diagnosed on the basis of imaging findings. Additional follow-up is necessary, and the long-term side effects of the procedure still need to be determined.

  10. Quantifying and improving the efficiency of Gamma Knife treatment plans for brain metastases: results of a 1-year audit.

    PubMed

    Wright, Gavin; Hatfield, Paul; Loughrey, Carmel; Reiner, Beatrice; Bownes, Peter

    2014-12-01

    A method for quantifying the efficiency of Gamma Knife treatment plans for metastases was previously implemented by the authors to retrospectively identify the least efficient plans and has provided insights into improved planning strategies. The aim of the current work was to ascertain whether those insights led to improved treatment plans. Following completion of the initial study, a 1-year audit of metastasis plans created at St. James's Institute of Oncology was carried out. Audited recent plans were compared with the earlier plans of the initial study, in terms of their efficiency and dosimetric quality. The statistical significance of any differences between relevant plan parameters was quantified by Mann-Whitney U-tests. Comparisons were made between all plans and repeated for a reduced set of plans from which the smallest lesions treated with a single 4-mm shot were excluded. The plan parameters compared were a plan efficiency index (PEI), the number of shots, Paddick conformity index (PCI), gradient index (GI), and percent coverage (of the lesion by the prescription isodose). A total of 157 metastatic lesions were included in the audit and were compared with 241 in the initial study. In a comparison of all cases, the audited plans achieved a higher median PEI score than did the earlier plans from the initial study (1.08 vs 1.02), indicating improved efficiency of the audited plans. When the smallest lesions (for which there was little scope for varying plan strategy) were discounted, the improvement in median PEI score was greater (1.23 vs 1.03, p < 0.001). This improvement in efficiency corresponds to an estimated mean (maximum) time saving of 15% (66%) per lesion (11 minutes [64 minutes] on the day of treatment). The modified planning strategy yielding these efficiency improvements did not rely on the use of significantly fewer shots (median 11 vs 11 shots, p = 0.924), nor did it result in significant detriment to dosimetric quality (median coverage 99

  11. Stereotactic radiosurgery for trigeminal pain secondary to recurrent malignant skull base tumors.

    PubMed

    Phan, Jack; Pollard, Courtney; Brown, Paul D; Guha-Thakurta, Nandita; Garden, Adam S; Rosenthal, David I; Fuller, Clifton D; Frank, Steven J; Gunn, G Brandon; Morrison, William H; Ho, Jennifer C; Li, Jing; Ghia, Amol J; Yang, James N; Luo, Dershan; Wang, He C; Su, Shirley Y; Raza, Shaan M; Gidley, Paul W; Hanna, Ehab Y; DeMonte, Franco

    2018-04-27

    OBJECTIVE The objective of this study was to assess outcomes after Gamma Knife radiosurgery (GKRS) re-irradiation for palliation of patients with trigeminal pain secondary to recurrent malignant skull base tumors. METHODS From 2009 to 2016, 26 patients who had previously undergone radiation treatment to the head and neck received GKRS for palliation of trigeminal neuropathic pain secondary to recurrence of malignant skull base tumors. Twenty-two patients received single-fraction GKRS to a median dose of 17 Gy (range 15-20 Gy) prescribed to the 50% isodose line (range 43%-55%). Four patients received fractionated Gamma Knife Extend therapy to a median dose of 24 Gy in 3 fractions (range 21-27 Gy) prescribed to the 50% isodose line (range 45%-50%). Those with at least a 3-month follow-up were assessed for symptom palliation. Self-reported pain was evaluated by the numeric rating scale (NRS) and MD Anderson Symptom Inventory-Head and Neck (MDASI-HN) pain score. Frequency of as-needed (PRN) analgesic use and opioid requirement were also assessed. Baseline opioid dose was reported as a fentanyl-equivalent dose (FED) and PRN for breakthrough pain use as oral morphine-equivalent dose (OMED). The chi-square and Student t-tests were used to determine differences before and after GKRS. RESULTS Seven patients (29%) were excluded due to local disease progression. Two experienced progression at the first follow-up, and 5 had local recurrence from disease outside the GKRS volume. Nineteen patients were assessed for symptom palliation with a median follow-up duration of 10.4 months (range 3.0-34.4 months). At 3 months after GKRS, the NRS scores (n = 19) decreased from 4.65 ± 3.45 to 1.47 ± 2.11 (p < 0.001); MDASI-HN pain scores (n = 13) decreased from 5.02 ± 1.68 to 2.02 ± 1.54 (p < 0.01); scheduled FED (n = 19) decreased from 62.4 ± 102.1 to 27.9 ± 45.5 mcg/hr (p < 0.01); PRN OMED (n = 19) decreased from 43.9 ± 77.5 to 10.9 ± 20.8 mg/day (p = 0.02); and frequency of any

  12. Complications Following Linear Accelerator Based Stereotactic Radiation for Cerebral Arteriovenous Malformations

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Skjoth-Rasmussen, Jane, E-mail: jane@skjoeth-rasmussen.d; Roed, Henrik; Ohlhues, Lars

    2010-06-01

    Purpose: Primarily, gamma knife centers are predominant in publishing results on arteriovenous malformations (AVM) treatments including reports on risk profile. However, many patients are treated using a linear accelerator-most of these at smaller centers. Because this setting is different from a large gamma knife center, the risk profile at Linac departments could be different from the reported experience. Prescribed radiation doses are dependent on AVM volume. This study details results from a medium sized Linac department center focusing on risk profiles. Method and Materials: A database was searched for all patients with AVMs. We included 50 consecutive patients with amore » minimum of 24 months follow-up (24-51 months). Results: AVM occlusion was verified in 78% of patients (39/50). AVM occlusion without new deficits (excellent outcome) was obtained in 44%. Good or fair outcome (AVM occlusion with mild or moderate new deficits) was seen in 30%. Severe complications after AVM occlusion occurred in 4% with a median interval of 15 months after treatment (range, 1-26 months). Conclusions: We applied an AVM grading score developed at the Mayo Clinic to predict probable outcome after radiosurgery in a large patient population treated with Gamma knife. A cutoff above and below a score of 1.5 could not discriminate between the likelihood of having an excellent outcome (approximately 45%). The chance of having an excellent or good outcome was slightly higher in patients with an AVM score below 1.5 (64% vs. 57%).« less

  13. A geometrically based method for automated radiosurgery planning.

    PubMed

    Wagner, T H; Yi, T; Meeks, S L; Bova, F J; Brechner, B L; Chen, Y; Buatti, J M; Friedman, W A; Foote, K D; Bouchet, L G

    2000-12-01

    A geometrically based method of multiple isocenter linear accelerator radiosurgery treatment planning optimization was developed, based on a target's solid shape. Our method uses an edge detection process to determine the optimal sphere packing arrangement with which to cover the planning target. The sphere packing arrangement is converted into a radiosurgery treatment plan by substituting the isocenter locations and collimator sizes for the spheres. This method is demonstrated on a set of 5 irregularly shaped phantom targets, as well as a set of 10 clinical example cases ranging from simple to very complex in planning difficulty. Using a prototype implementation of the method and standard dosimetric radiosurgery treatment planning tools, feasible treatment plans were developed for each target. The treatment plans generated for the phantom targets showed excellent dose conformity and acceptable dose homogeneity within the target volume. The algorithm was able to generate a radiosurgery plan conforming to the Radiation Therapy Oncology Group (RTOG) guidelines on radiosurgery for every clinical and phantom target examined. This automated planning method can serve as a valuable tool to assist treatment planners in rapidly and consistently designing conformal multiple isocenter radiosurgery treatment plans.

  14. Independent Monte-Carlo dose calculation for MLC based CyberKnife radiotherapy

    NASA Astrophysics Data System (ADS)

    Mackeprang, P.-H.; Vuong, D.; Volken, W.; Henzen, D.; Schmidhalter, D.; Malthaner, M.; Mueller, S.; Frei, D.; Stampanoni, M. F. M.; Dal Pra, A.; Aebersold, D. M.; Fix, M. K.; Manser, P.

    2018-01-01

    This work aims to develop, implement and validate a Monte Carlo (MC)-based independent dose calculation (IDC) framework to perform patient-specific quality assurance (QA) for multi-leaf collimator (MLC)-based CyberKnife® (Accuray Inc., Sunnyvale, CA) treatment plans. The IDC framework uses an XML-format treatment plan as exported from the treatment planning system (TPS) and DICOM format patient CT data, an MC beam model using phase spaces, CyberKnife MLC beam modifier transport using the EGS++ class library, a beam sampling and coordinate transformation engine and dose scoring using DOSXYZnrc. The framework is validated against dose profiles and depth dose curves of single beams with varying field sizes in a water tank in units of cGy/Monitor Unit and against a 2D dose distribution of a full prostate treatment plan measured with Gafchromic EBT3 (Ashland Advanced Materials, Bridgewater, NJ) film in a homogeneous water-equivalent slab phantom. The film measurement is compared to IDC results by gamma analysis using 2% (global)/2 mm criteria. Further, the dose distribution of the clinical treatment plan in the patient CT is compared to TPS calculation by gamma analysis using the same criteria. Dose profiles from IDC calculation in a homogeneous water phantom agree within 2.3% of the global max dose or 1 mm distance to agreement to measurements for all except the smallest field size. Comparing the film measurement to calculated dose, 99.9% of all voxels pass gamma analysis, comparing dose calculated by the IDC framework to TPS calculated dose for the clinical prostate plan shows 99.0% passing rate. IDC calculated dose is found to be up to 5.6% lower than dose calculated by the TPS in this case near metal fiducial markers. An MC-based modular IDC framework was successfully developed, implemented and validated against measurements and is now available to perform patient-specific QA by IDC.

  15. RT-06GAMMA KNIFE SURGERY AFTER NAVIGATION-GUIDED ASPIRATION FOR CYSTIC METASTATIC BRAIN TUMORS

    PubMed Central

    Chiba, Yasuyoshi; Mori, Kanji; Toyota, Shingo; Kumagai, Tetsuya; Yamamoto, Shota; Sugano, Hirofumi; Taki, Takuyu

    2014-01-01

    Metastatic brain tumors over 3 cm in diameter (volume of 14.1ml) are generally considered poor candidates for Gamma Knife surgery (GKS). We retrospectively assessed the method and efficacy of GKS for large cystic metastatic brain tumors after navigation-guided aspiration under local anesthesia. From September 2007 to April 2014, 38 cystic metastatic brain tumors in 32 patients (12 males, 20 females; mean age, 63.2 years) were treated at Kansai Rosai Hospital. The patients were performed navigation-guided cyst aspiration under local anesthesia, then at the day or the next day, were performed GKS and usually discharged on the day. The methods for preventing of leptomeningeal dissemination are following: 1) puncture from the place whose cerebral thickness is 1 cm or more; 2) avoidance of Ommaya reservoir implantation; and 3) placement of absorbable gelatin sponge to the tap tract. Tumor volume, including the cystic component, decreased from 25.4 ml (range 8.7-84.7 ml) to 11.4 ml (range 2.9-36.7 ml) following aspiration; the volume reduction was approximately 51.6%. Follow-up periods in the study population ranged from 0 to 24 months (median 3.5 months). The overall median survival was 6.7 months. There was no leptomeningeal dissemination related to the aspiration. One patient experienced radiation necrosis after GKS, one patient experienced re-aspiration by failure of aspiration, and two patients experienced surgical resections and one patient experienced re-aspiration by cyst regrowth after GKS. Long-term hospitalization is not desirable for the patients with brain metastases. In japan, Long-term hospitalization is required for surgical resection or whole brain radiation therapy, but only two days hospitalization is required for GKS after navigation-guided aspiration at our hospital. This GKS after navigation-guided aspiration is more effective and less invasive than surgical resection or whole brain radiation therapy.

  16. Evaluation of a new disposable silicon limbal relaxing incision knife by experienced users.

    PubMed

    Albanese, John; Dugue, Geoffrey; Parvu, Valentin; Bajart, Ann M; Lee, Edwin

    2009-12-21

    Previous research has suggested that the silicon BD Atomic Edge knife has superior performance characteristics when compared to a metal knife and performance similar to diamond knife when making various incisions. This study was designed to determine whether a silicon accurate depth knife has equivalent performance characteristics when compared to a diamond limbal relaxing incision (LRI) knife and superior performance characteristics when compared to a steel accurate depth knife when creating limbal relaxing incision. Sixty-five ophthalmic surgeons with limbal relaxing incision experience created limbal relaxing incisions in ex-vivo porcine eyes with silicon and steel accurate depth knives and diamond LRI knives. The ophthalmic surgeons rated multiple performance characteristics of the knives on Visual Analog Scales. The observed differences between the silicon knife and diamond knife were found to be insignificant. The mean ratio between the performance of the silicon knife and the diamond knife was shown to be greater than 90% (with 95% confidence). The silicon knife's mean performance was significantly higher than the performance of the steel knife for all characteristics. (p-value < .05) For experienced users, the silicon accurate depth knife was found to be equivalent in performance to the diamond LRI knife and superior to the steel accurate depth knife when making limbal relaxing incisions in ex vivo porcine eyes. Disposable silicon LRI knives may be an alternative to diamond LRI knives.

  17. Dosimetry for Small Fields in Stereotactic Radiosurgery Using Gafchromic MD-V2-55 Film, TLD-100 and Alanine Dosimeters

    PubMed Central

    Massillon-JL, Guerda; Cueva-Prócel, Diego; Díaz-Aguirre, Porfirio; Rodríguez-Ponce, Miguel; Herrera-Martínez, Flor

    2013-01-01

    This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK) and a modified linear accelerator (linac) for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55), alanine and thermoluminescent (TLD-100) dosimeters and compared with conventional dosimetry systems. Detectors were calibrated in terms of absorbed dose to water in 60Co gamma-ray and 6 MV x-ray reference (10×10 cm2) fields using an ionization chamber calibrated at a standards laboratory. Absorbed dose to water rate computed with MD-V2-55 was higher than that obtained with the others dosimeters, possibly due to a smaller volume averaging effect. Ratio between the dose-rates determined with each dosimeter and those obtained with the film was evaluated for both treatment modalities. For the LGK, the ratio decreased as the dosimeter size increased and remained constant for collimator diameters larger than 8 mm. The same behaviour was observed for the linac and the ratio increased with field size, independent of the dosimeter used. These behaviours could be explained as an averaging volume effect due to dose gradient and lack of electronic equilibrium. Evaluation of the output factors for the LGK collimators indicated that, even when agreement was observed between Monte Carlo simulation and measurements with different dosimeters, this does not warrant that the absorbed dose to water rate in the field was properly known and thus, investigation of the reference dosimetry should be an important issue. These results indicated that alanine dosimeter provides a high degree of accuracy but cannot be used in fields smaller than 20 mm diameter. Gafchromic film can be considered as a suitable methodology for reference dosimetry. TLD dosimeters are not appropriate in fields

  18. [Research progress of needles with knife-edge for carotid cardiac syndrome].

    PubMed

    Tan, Lingqiong; Zhao, Yanling

    2015-04-01

    According to topographic anatomy, pathogenesis and by retrieving, summarizing and analyzing literature regarding needle-knife and needles with knife-edge for carotid cardiac syndrome, it is found out that clinical misdiagnosis rate of carotid cardiac syndrome is considerably high. Needle-knife and needles with knife-edge could significantly improve the clinical symptoms of carotid cardiac syndrome, showing characteristic and advantage in treatment, but it is deficient in technique standard and efficacy criteria that should be united and authoritative. Researches regarding pathogenesis of carotid cardiac syndrome are not systematic. Clinical observation regarding long-term efficacy and relapse of needle-knife and needles with knife-edge treatment is rare. It is believed that the awareness on carotid cardiac syndrome should be increased to reduce misdiagnosis; scientific and standardized technique standard and efficacy criteria should be established; systematic and comprehensive researches regarding mechanism of needle-knife and needles with knife-edge for carotid cardiac syndrome should be launched; besides, clinical discussion regarding its long-term efficacy should start to provide a better clinical guideline.

  19. No need to change the skin knife in modern arthroplasty surgery.

    PubMed

    Ottesen, C; Skovby, A; Troelsen, A; Specht, C; Friis-Møller, A; Husted, H

    2014-08-01

    Earlier studies have found varying contamination rates using separate skin and deep knives in total hip (THA) and total knee (TKA) arthroplasty surgery. Previous studies were primarily conducted in the setting of concomitant use of laminar airflow and/or plastic adhesive draping. This has lead to conflicting conclusions regarding discarding the skin knife or not. This study evaluates the prevalence of contamination of a separate skin knife using modern antiseptic technique in primary THA and TKA without laminar airflow. Three knives from each primary THA and TKA surgery in non-laminar airflow operating rooms were collected: one used for the skin, one used for deeper tissues and one control knife. A total of 831 knife blades from 277 patients were cultured 12 days. Contamination of the skin knife was found in eight patients (2.8 %), contamination of the "deep" knife in five patients (1.8 %) and contamination of the control knife in five patients (1.8 %). No patient developed an infection with 1-year follow-up. Our findings suggest a very low rate of contamination of the skin knife using modern antiseptic technique without laminar airflow and/or plastic adhesive draping and do not support the use of a separate skin knife in arthroplasty surgery.

  20. Is it possible to avoid hypopituitarism after irradiation of pituitary adenomas by the Leksell gamma knife?

    PubMed

    Marek, Josef; Jezková, Jana; Hána, Václav; Krsek, Michal; Bandúrová, L'ubomíra; Pecen, Ladislav; Vladyka, Vilibald; Liscák, Roman

    2011-02-01

    Radiation therapy is one of the treatment options for pituitary adenomas. The most common side effect associated with Leksell gamma knife (LGK) irradiation is the development of hypopituitarism. The aim of this study was to verify that hypopituitarism does not develop if the maximum mean dose to pituitary is kept under 15 Gy and to evaluate the influence of maximum distal infundibulum dose on the development of hypopituitarism. We followed the incidence of hypopituitarism in 85 patients irradiated with LGK in 1993-2003. The patients were divided in two subgroups: the first subgroup followed prospectively (45 patients), irradiated with a mean dose to pituitary <15 Gy; the second subgroup followed retrospectively 1993-2001 and prospectively 2001-2009 (40 patients), irradiated with a mean dose to pituitary >15 Gy. Serum TSH, free thyroxine, testosterone or 17β-oestradiol, IGF1, prolactin and cortisol levels were evaluated before and every 6 months after LGK irradiation. Hypopituitarism after LGK irradiation developed only in 1 out of 45 (2.2%) patients irradiated with a mean dose to pituitary <15 Gy, in contrast to 72.5% patients irradiated with a mean dose to pituitary >15 Gy. The radiation dose to the distal infundibulum was found as an independent factor of hypopituitarism with calculated maximum safe dose of 17 Gy. Keeping the mean radiation dose to pituitary under 15 Gy and the dose to the distal infundibulum under 17 Gy prevents the development of hypopituitarism following LGK irradiation.

  1. Intracranial stereotactic radiosurgery with an adapted linear accelerator vs. robotic radiosurgery: Comparison of dosimetric treatment plan quality.

    PubMed

    Treuer, Harald; Hoevels, Moritz; Luyken, Klaus; Visser-Vandewalle, Veerle; Wirths, Jochen; Kocher, Martin; Ruge, Maximilian

    2015-06-01

    Stereotactic radiosurgery with an adapted linear accelerator (linac-SRS) is an established therapy option for brain metastases, benign brain tumors, and arteriovenous malformations. We intended to investigate whether the dosimetric quality of treatment plans achieved with a CyberKnife (CK) is at least equivalent to that for linac-SRS with circular or micromultileaf collimators (microMLC). A random sample of 16 patients with 23 target volumes, previously treated with linac-SRS, was replanned with CK. Planning constraints were identical dose prescription and clinical applicability. In all cases uniform optimization scripts and inverse planning objectives were used. Plans were compared with respect to coverage, minimal dose within target volume, conformity index, and volume of brain tissue irradiated with ≥ 10 Gy. Generating the CK plan was unproblematic with simple optimization scripts in all cases. With the CK plans, coverage, minimal target volume dosage, and conformity index were significantly better, while no significant improvement could be shown regarding the 10 Gy volume. Multiobjective comparison for the irradiated target volumes was superior in the CK plan in 20 out of 23 cases and equivalent in 3 out of 23 cases. Multiobjective comparison for the treated patients was superior in the CK plan in all 16 cases. The results clearly demonstrate the superiority of the irradiation plan for CK compared to classical linac-SRS with circular collimators and microMLC. In particular, the average minimal target volume dose per patient, increased by 1.9 Gy, and at the same time a 14% better conformation index seems to be an improvement with clinical relevance.

  2. Long-term outcomes after radiosurgery for glomus jugulare tumors.

    PubMed

    Sallabanda, Kita; Barrientos, Hernan; Isernia Romero, Daniela Angelina; Vargas, Cristian; Gutierrez Diaz, Jose Angel; Peraza, Carmen; Rivin Del Campo, Eleonor; Praena-Fernandez, Juan Manuel; López-Guerra, José Luis

    2018-04-01

    The treatment of glomus jugulare tumors (GJT) remains controversial due to high morbidity. Historically, these tumors have primarily been managed surgically. The purpose of this retrospective review was to assess the tumor and clinical control rates as well as long-term toxicity of GJT treated with radiosurgery. Between 1993 and 2014, 30 patients with GJT (31 tumors) were managed with radiosurgery. Twenty-one patients were female and the median age was 59 years. Twenty-eight patients (93%) were treated with radiosurgery, typically at 14 Gy ( n = 26), and 2 patients (7%) with stereotactic radiosurgery. Sixteen cases (52%) had undergone prior surgery. The mean follow-up was 4.6 years (range 1.5-12). Crude overall survival, tumor control, clinical control, and long-term grade 1 toxicity rates were 97%, 97%, 97%, and 13% (4/30), respectively. No statistically significant risk factor was associated with lower tumor control in our series. Univariate analysis showed a statistically significant association between patients having 1 cranial nerve (CN) involvement before radiosurgery and a higher risk of lack of improvement of symptoms (odds ratio 5.24, 95% confidence interval 1.06-25.97, p = .043). Radiosurgery is an effective and safe treatment modality for GJT. Patients having 1 CN involvement before radiosurgery show a higher risk of lack of improvement of symptoms.

  3. [Meta-analysis of needle-knife treatment on cervical spondylosis].

    PubMed

    Kan, Li-Li; Wang, Hai-Dong; Liu, An-Guo

    2013-11-01

    To assess the efficacy of cervical spondylosis by needle-knife treatment according to the correlated literature of RCT,to compare advantages of needle-knife treatment. Randomized Controlled Trials about needle-knife treatment of cervical spondylosis were indexed from Chinese HowNet (CNKI) and Wanfang (WF) from 2000 to 2012, then were analyzed the efficacy by Review Manager 5.1 software. A total of 13 RCT literatures and 1 419 patients were included. The methods of included studies were poor in quality evaluation because of large sample and multi-center RCT studies was lacked, randomization method was not accurate enough, diagnostic criteria and efficacy evaluation were various, only four studies described long-term efficacy, most of the literature didn't describe the adverse event and fall off,all studies did not use the blind method. The Meta analysis outcome showed overall efficiency of needle-knife therapy was better than acupuncture and traction. Needle-knife therapy compared with Acupuncture, the total RR = 0.19, 95% confidence interval was (0.15, 0.24), P < 0.000.01. Compared with traction therapy the total RR = 1.30, 95% confidence intervalwas (1.18,1.42), P < 0.00001. Compared with acupuncture therapy,the overall effectiveness of needle-knife therapy is higher;compared with traction therapy, although,needle-knife therapy has a high overall effectiveness, but because of the loss of total sample size, the outcome RCT researches to confirm.

  4. Stereotactic radiosurgery - CyberKnife

    MedlinePlus

    ... slides into a machine that delivers radiation. A robotic arm controlled by a computer moves around you. ... people who are too high risk for conventional surgery. This may be due to age or other ...

  5. SU-E-T-471: Improvement of Gamma Knife Treatment Planning Through Tumor Control Probability for Metastatic Brain Tumors

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huang, Z; Feng, Y; Lo, S

    2015-06-15

    Purpose: The dose–volume histogram (DVH) has been normally accepted as a tool for treatment plan evaluation. However, spatial information is lacking in DVH. As a supplement to the DVH in three-dimensional treatment planning, the differential DVH (DDVH) provides the spatial variation, the size and magnitude of the different dose regions within a region of interest, which can be incorporated into tumor control probability model. This study was to provide a method in evaluating and improving Gamma Knife treatment planning. Methods: 10 patients with brain metastases from different primary tumors including melanoma (#1,#4,#5, #10), breast cancer (#2), prostate cancer (#3) andmore » lung cancer (#6–9) were analyzed. By using Leksell GammaPlan software, two plans were prepared for each patient. Special attention was given to the DDVHs that were different for different plans and were used for a comparison between two plans. Dose distribution inside target and tumor control probability (TCP) based on DDVH were calculated, where cell density and radiobiological parameters were adopted from literature. The plans were compared based on DVH, DDVH and TCP. Results: Using DVH, the coverage and selectivity were the same between plans for 10 patients. DDVH were different between two plans for each patient. The paired t-test showed no significant difference in TCP between the two plans. For brain metastases from melanoma (#1, #4–5), breast cancer (#2) and lung cancer (#6–8), the difference in TCP was less than 5%. But the difference in TCP was about 6.5% for patient #3 with the metastasis from prostate cancer, 10.1% and 178.7% for two patients (#9–10) with metastasis from lung cancer. Conclusion: Although DVH provides average dose–volume information, DDVH provides differential dose– volume information with respect to different regions inside the tumor. TCP provides radiobiological information and adds additional information on improving treatment planning as well as

  6. Laparoscopic pyloromyotomy: is a knife really necessary?

    PubMed

    Jain, Vishesh; Choudhury, Subhasis Roy; Chadha, Rajiv; Puri, Archana; Naga, Abhimanyu Singh

    2012-02-01

    Laparoscopic pyloromyotomy (LP) is currently accepted as a suitable treatment modality for infantile hypertrophic pyloric stenosis (IHPS). In this report, we describe some technical modifications of LP using a 3- or 5-mm hook with electrocautery as a substitute for a knife for incising the pylorus. The outcomes of LP using a standard retractable pyloromyotomy knife are compared with those of LP using a hook electrocautery. The patients with ultrasound proven IHPS who had undergone LP in a single institution from December 2008 to April 2010 were retrospectively analyzed. Incision on the pylorus was made with a 3-mm pyloromyotomy knife in the initial 12 cases. However, in the latter part of the study, a 3- or 5-mm hook with electrocautery was used for the incision. A Maryland dissector was used for completing the pyloromyotomy. The results were compared in terms of duration of surgery, complications, time taken to establish the first full feed, requirement of analgesics, postoperative emesis, and postoperative stay in the hospital. Independent sample t test and the Chi-square test were used for statistical analysis. Of the 27 patients analyzed, 12 underwent LP using a pyloromyotomy knife and the remaining 15 patients were operated on using a hook with electrocautery instead of the knife. The operating time, time taken to establish the first full feed, and duration of hospital stay were comparable among the two groups with no statistically significant difference. No complications were recorded in either group. Use of hook electrocautery for incising the pylorus provides a bloodless field without affecting the postoperative recovery and outcome. It also obviates any need of specialized instruments like a pyloromyotomy knife or other sharp instruments for pyloric incision.

  7. The SKED: speckle knife edge detector

    NASA Astrophysics Data System (ADS)

    Sharpies, S. D.; Light, R. A.; Achamfuo-Yeboah, S. O.; Clark, M.; Somekh, M. G.

    2014-06-01

    The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device.

  8. Using the phacoemulsification crescent knife in dacryocystorhinostomy.

    PubMed

    Fong, K S; Koh, A H; Choo, C T

    1998-04-01

    Dacryocystorhinostomy is an effective treatment for nasolacrimal duct obstruction. Most techniques employ a conventional blade or knife in making the incision of the nasal mucosa and lacrimal sac. The authors describe the use of a phacoemulsification crescent knife for this purpose. This technique can be effective and at the same time safer and easier to perform.

  9. Combining stereotactic angiography and 3D time-of-flight magnetic resonance angiography in treatment planning for arteriovenous malformation radiosurgery.

    PubMed

    Bednarz, G; Downes, B; Werner-Wasik, M; Rosenwasser, R H

    2000-03-15

    This study was initiated to evaluate the advantages of using three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA), as an adjuvant to conventional stereotactic angiography, in obtaining three-dimensional information about an arteriovenous malformation (AVM) nidus and in optimizing radiosurgical treatment plans. Following angiography, contrast-enhanced MRI and MRA studies were obtained in 22 consecutive patients undergoing Gamma Knife radiosurgery for AVM. A treatment plan was designed, based on the angiograms and modified as necessary, using the information provided by MRA. The quantitative analysis involved calculation of the ratio of the treated volume to the MRA nidus volume (the tissue volume ratio [TVR]) for the initial and final treatment plans. In 12 cases (55%), the initial treatment plans were modified after including the MRA information in the treatment planning process. The mean TVR for the angiogram-based plans was 1.63 (range 1.17-2.17). The mean coverage of the MRA nidus by the angiogram-based plans was 93% (range 73-99%). The mean MRA nidus volume was 2.4 cc (range 0. 6-5.3 cc). The MRA-based modifications resulted in increased conformity with the mean TVR of 1.46 (range 1.20-1.74). These modifications were caused by MRA revealing irregular nidi and/or vascular components superimposed on the angiographic projections of the nidi. In a number of cases, the information from MRA was essential in defining the nidus when the projections of the angiographic outlines showed different superior and/or inferior extent of the nidus. In two cases, MRA revealed irregular nidi, correlating well with the angiograms and showed that the angiographically acceptable plans undertreated 27% of the MRA nidus in one case and 18% of the nidus in the other case. In the remaining 10 cases (45%), both MRI and MRA failed to detect the nidus due to surgical clip artifacts and the presence of embolizing glue. The 3D TOF MRA provided information on irregular

  10. Single fraction spine radiosurgery for myeloma epidural spinal cord compression.

    PubMed

    Jin, Ryan; Rock, Jack; Jin, Jian-Yue; Janakiraman, Nalini; Kim, Jae Ho; Movsas, Benjamin; Ryu, Samuel

    2009-01-01

    Radiosurgery delivers highly focused radiation beams to the defined target with high precision and accuracy. It has been demonstrated that spine radiosurgery can be safely used for treatment of spine metastasis with rapid and durable pain control, but without detrimental effects to the spinal cord. This study was carried out to determine the role of single fraction radiosurgery for epidural spinal cord compression due to multiple myeloma. A total of 31 lesions in 24 patients with multiple myeloma, who presented with epidural spinal cord compression, were treated with spine radiosurgery. Single fraction radiation dose of 10-18 Gy (median of 16 Gy) was administered to the involved spine including the epidural or paraspinal tumor. Patients were followed up with clinical exams and imaging studies. Median follow-up was 11.2 months (range 1-55). Primary endpoints of this study were pain control, neurological improvement, and radiographic tumor control. Overall pain control rate was 86%; complete relief in 54%, and partial relief in 32% of the patients. Seven patients presented with neurological deficits. Five patients neurologically improved or became normal after radiosurgery. Complete radiographic response of the epidural tumor was noted in 81% at 3 months after radiosurgery. During the follow-up time, there was no radiographic or neurological progression at the treated spine. The treatment was non-invasive and well tolerated. Single fraction radiosurgery achieved an excellent clinical and radiographic response of myeloma epidural spinal cord compression. Radiosurgery can be a viable treatment option for myeloma epidural compression.

  11. 10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

  12. 10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

  13. 10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

  14. 10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

  15. 10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

  16. Cross-Grain Knife Planing Improves Surface Quality and Utilization of Aspen

    Treesearch

    Harold A. Stewart

    1971-01-01

    Aspen at 6 percent moisture content was planed parallel to the grain and across the grain on a cabinet planer with a 25? rake angle, 1/16- and 1/32-inch depth of cut, and 20 knife marks per inch. Aspen was also cross-grain knife planed with a 45? rake angle, 1/32-, 1/16-, and 1/8-inch depths of cut, and 20, 10, 5, and 2.5 knife marks per inch. Cross-grain knife...

  17. Laparoscopic pyloromyotomy: comparing the arthrotomy knife to the Bovie blade.

    PubMed

    Thomas, Priscilla G; Sharp, Nicole E; St Peter, Shawn D

    2014-07-01

    Laparoscopic pyloromyotomy was performed at our institution using an arthrotomy knife until it became unavailable in 2010. Thus, we adapted the use of the blunt Bovie tip, which can be used with or without electrocautery to perform the myotomy. This study compared the outcomes between using the arthrotomy knife versus the Bovie blade in laparoscopic pyloromyotomies. Retrospective review was performed on all laparoscopic pyloromyotomy patients from October 2007 to September 2012. Arthrotomy knife pyloromyotomy patients were compared with those performed with the Bovie blade. Patient demographics, diagnostic measurements, electrolyte levels, length of stay, operative time, and complications were compared. A total of 381 patients were included, with 191 in the arthrotomy group and 190 in the Bovie blade group. No significant differences existed between groups in age, weight, gender, pyloric dimensions, electrolyte levels, or length of stay. Mean operative times were 15.8±5.6 min with knife and 16.4±5.3 min for Bovie blade (P=0.24). In the arthrotomy knife group, there was one incomplete pyloromyotomy and one omental herniation. There was one wound infection in each group. Readmission rate was greater in the arthrotomy knife group (5.7%) versus the Bovie blade group (3.1%). The Bovie blade appears to offer no objective disadvantages compared with the arthrotomy knife when performing laparoscopic pyloromyotomy. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Best of the Radiosurgery Society® Scientific Meeting 2014: stereotactic radiosurgery/stereotactic body radiotherapy treatment of extracranial and intracranial lesions.

    PubMed

    Mahadevan, Anand; Bucholz, Richard; Gaya, Andrew M; Kresl, John J; Mantz, Constantine; Minnich, Douglas J; Muacevic, Alexander; Medbery, Clinton; Yang, Jun; Caglar, Hale Basak; Davis, Joanne N

    2014-12-01

    The SRS/SBRT Scientific Meeting 2014, Minneapolis, MN, USA, 7-10 May 2014. The Radiosurgery Society(®), a professional medical society dedicated to advancing the field of stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), held the international Radiosurgery Society Scientific Meeting, from 7-10 May 2014 in Minneapolis (MN, USA). This year's conference attracted over 400 attendants from around the world and featured over 100 presentations (46 oral) describing the role of SRS/SBRT for the treatment of intracranial and extracranial malignant and nonmalignant lesions. This article summarizes the meeting highlights for SRS/SBRT treatments, both intracranial and extracranial, in a concise review.

  19. Mapping clinical outcomes expectations to treatment decisions: an application to vestibular schwannoma management.

    PubMed

    Cheung, Steven W; Aranda, Derick; Driscoll, Colin L W; Parsa, Andrew T

    2010-02-01

    Complex medical decision making obligates tradeoff assessments among treatment outcomes expectations, but an accessible tool to perform the necessary analysis is conspicuously absent. We aimed to demonstrate methodology and feasibility of adapting conjoint analysis for mapping clinical outcomes expectations to treatment decisions in vestibular schwannoma (VS) management. Prospective. Tertiary medical center and US-based otologists/neurotologists. Treatment preference profiles among VS stakeholders-61 younger and 74 older prospective patients, 61 observation patients, and 60 surgeons-were assessed for the synthetic VS case scenario of a 10-mm tumor in association with useful hearing and normal facial function. Treatment attribute utility. Conjoint analysis attribute levels were set in accordance to the results of a meta-analysis. Forty-five case series were disaggregated to formulate microsurgery facial nerve and hearing preservation outcomes expectations models. Attribute utilities were computed and mapped to the realistic treatment choices of translabyrinthine craniotomy, middle fossa craniotomy, and gamma knife radiosurgery. Among the treatment attributes of likelihoods of causing deafness, temporary facial weakness for 2 months, and incurable cancer within 20 years, and recovery time, permanent deafness was less important to tumor surgeons, and temporary facial weakness was more important to tumor surgeons and observation patients (Wilcoxon rank-sum, p < 0.001). Inverse mapping of preference profiles to realistic treatment choices showed all study cohorts were inclined to choose gamma knife radiosurgery. Mapping clinical outcomes expectations to treatment decisions for a synthetic clinical scenario revealed inhomogeneous drivers of choice selection among study cohorts. Medical decision engines that analyze personal preferences of outcomes expectations for VS and many other diseases may be developed to promote shared decision making among health care stakeholders

  20. Predictors of quality of life and survival following Gamma Knife surgery for lung cancer brain metastases: a prospective study.

    PubMed

    Bragstad, Sidsel; Flatebø, Marianne; Natvig, Gerd Karin; Eide, Geir Egil; Skeie, Geir Olve; Behbahani, Maziar; Pedersen, Paal-Henning; Enger, Per Øyvind; Skeie, Bente Sandvei

    2017-08-18

    OBJECTIVE Lung cancer (LC) patients who develop brain metastases (BMs) have a poor prognosis. Estimations of survival and risk of treatment-related deterioration in quality of life (QOL) are important when deciding on treatment. Although we know of several prognostic factors for LC patients with BMs, the role of QOL has not been established. Authors of this study set out to evaluate changes in QOL following Gamma Knife surgery (GKS) for BMs in LC patients and QOL as a prognostic factor for survival. METHODS Forty-four of 48 consecutive LC patients with BMs underwent GKS in the period from May 2010 to September 2011, and their QOL was prospectively assessed before and 1, 3, 6, 9, and 12 months after GKS by using the Functional Assessment of Cancer Therapy-Brain (FACT-BR) questionnaire. A mixed linear regression model was used to identify potential predictive factors for QOL and to assess the effect of GKS and the disease course on QOL at follow-up. RESULTS Mean QOL as measured by the brain cancer subscale (BRCS) of the FACT-BR remained stable from baseline (score 53.0) up to 12 months post-GKS (57.1; p = 0.624). The BRCS score improved for 32 patients (72.3%) with a total BM volume ≤ 5 cm 3 . Mean improvement in these patients was 0.45 points each month of follow-up, compared to a decline of 0.50 points each month despite GKS treatment in patients with BM volumes > 5 cm 3 (p = 0.04). Asymptomatic BMs (p = 0.01), a lower recursive partitioning analysis (RPA) classification (p = 0.04), and a higher Karnofsky Performance Scale (KPS) score (p < 0.01) at baseline were predictors for a high, stable QOL after GKS. After multivariate analysis, a high KPS score (p < 0.01) remained the only positive predictor of a high, stable QOL post-GKS. Median survival post-GKS was 5.6 months (95% CI 1.0-10.3). A higher BRCS score (p = 0.01), higher KPS score (p = 0.01), female sex (p = 0.01), and the absence of liver (p = 0.02), adrenal (p = 0.02), and bone metastases (p = 0

  1. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nakaya, Kotaro; Department of Neurosurgery, Tokyo Women's Medical University, Tokyo; Niranjan, Ajay

    Purpose: This study evaluated the role of radiosurgery in the management of symptomatic patients with brainstem compression from benign basal tumors. Methods and Materials: Over a 17-year, period 246 patients (202 vestibular schwannomas and 44 meningiomas) with brainstem compression from benign skull-base tumors were managed with Gamma Knife radiosurgery. Median tumor volumes were 3.9 cm{sup 3} (range, 0.8-39.0 mL) and 6.6 mL (range, 1.6-25.1 mL) for vestibular schwannomas and meningiomas, respectively. For both tumors, a median marginal dose of 13 Gy was prescribed. Median follow-up of patients was 65 months for vestibular schwannomas and 60 months for meningiomas. Patients weremore » categorized into four groups on the basis of the tumor-brainstem relationship on neuroimaging. Results: Preservation of function was stratified according to grade of brainstem compression. We analyzed the effect of radiosurgery on symptoms of brainstem compression. The tumor control rate was 100 % for meningioma and 97% for vestibular schwannomas (although 5% required an additional procedure such as a ventriculoperitoneal shunt). In patients with vestibular schwannoma, serviceable hearing was preserved in 72.0%. Balance improved in 31.9%, remained unchanged in 56.5%, and deteriorated in 11.6% of patients who had imbalance at presentation. Balance improved significantly in patients who had less tumor compression (p = 0.0357) after radiosurgery. Symptoms improved in 43.2% of patients with meningioma. Conclusion: Radiosurgery is a minimally invasive option for patients with benign basal tumors that indent or distort the brainstem. A high tumor growth control rate and satisfactory rate of neurological preservation and symptom control can be obtained with radiosurgery.« less

  2. NEEDLE KNIFE SPHINCTEROTOMY - THE CHRIS HANI BARAGWANATH ACADEMIC HOSPITAL EXPERIENCE.

    PubMed

    Thomson, J T; Smith, M D; Omoshoro-Jones, J A O; Devar, J D; Khan, Z K; Jugmohan, B J

    2017-06-01

    Deep biliary cannulation is essential in performing a therapeutic ERCP. Cannulation can be enhanced through the utilization of a pre-cut by means of a needle knife sphincterotomy. Retrospective analysis of the Chris Hani Baragwanath Academic Hospital's ERCP database was performed. All ERCPs performed with the aid of a needle knife were identified and analysed for successful and unsuccessful deep biliary cannulation. 2830 ERCPs were performed during the study period. 369 (13%) required needle knife sphincterotomies and successful deep biliary cannulation was achieved in 229 (62%) of these patients. Repeat ERCPs were performed on 125 (34%) patients. 61 (49%) of the repeat ERCPs were performed because of previously failed cannulation. 34 (56%) of these repeat ERCPs resulted in successful deep biliary cannulation at re-attempt. 99% of successful cannulations at repeat ERCP had had a needle knife sphincterotomy at the first ERCP. Needle knife sphincterotomy improves deep biliary cannulation at initial ERCP and subsequent ERCPs with low incidences of complications.

  3. Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection.

    PubMed

    Yoshida, Naohisa; Toyonaga, Takashi; Murakami, Takaaki; Hirose, Ryohei; Ogiso, Kiyoshi; Inada, Yutaka; Rani, Rafiz Abdul; Naito, Yuji; Kishimoto, Mitsuo; Ohara, Yoshiko; Azuma, Takeshi; Itoh, Yoshito

    2017-01-01

    With respect to the knife's design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1-28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results.

  4. Efficacy of a Novel Narrow Knife with Water Jet Function for Colorectal Endoscopic Submucosal Dissection

    PubMed Central

    Inada, Yutaka; Rani, Rafiz Abdul; Naito, Yuji; Azuma, Takeshi; Itoh, Yoshito

    2017-01-01

    Backgrounds With respect to the knife's design in colorectal endoscopic submucosal dissection (ESD), diameter, water jet function, and electric power are important because these relate to efficient dissection. In this study, we analyzed a novel, narrow ball tip-typed ESD knife with water jet function (Flush knife BT-S, diameter: 2.2 mm, length: 2000 mm, Fujifilm Co., Tokyo, Japan) compared to a regular diameter knife (Flush knife BT, diameter: 2.6 mm, length: 1800 mm). Methods In laboratory and clinical research, electric power, knife insertion time, vacuum/suction amount with knife in the endoscopic channel, and water jet function were analyzed. We used a knife 2.0 mm long for BT-S and BT knives. Results The BT-S showed faster mean knife insertion time (sec) and better vacuum amount (ml/min) compared to the BT (insertion time: 16.7 versus 21.6, p < 0.001, vacuum amount: 38.0 versus 14.0, p < 0.01). Additionally, the water jet function of the BT-S was not inferior. In 39 colorectal ESD cases in two institutions, there were mean 4.7 times (range: 1–28) of knife insertion. Suction under knife happened 59% (23/39) and suction of fluid could be done in 100%. Conclusions Our study showed that the narrow knife allows significantly faster knife insertion, better vacuum function, and effective clinical results. PMID:29081793

  5. Gamma knife treatment for refractory cluster headache: prospective open trial.

    PubMed

    Donnet, A; Valade, D; Régis, J

    2005-02-01

    Since the initial report of Ford et al in 1998 no further study has evaluated radiosurgery of the trigeminal nerve in chronic cluster headache (CCH). We carried out a prospective open trial of neurosurgery and enrolled 10 patients (nine men, one woman; mean age 49.8 years, range 32-77) presenting with severe and drug resistant CCH (mean duration 9 years, range 2-33). The cisternal segment of the nerve was targeted with a single 4 mm collimator (80-85 Gy max). The mean follow up was 13.2 months. No improvement was observed in two patients and three patients had no further attacks. Three patients showed dramatic improvement with a few attacks per month or very few attacks over the last six months. Two patients were pain free for only one and two weeks and their headaches recurred with the same severity as before. Three patients developed paraesthesia with no hypoaesthesia, one developed hypoaesthesia, and one developed deafferentation pain. The rate and severity of trigeminal nerve injury appeared to be significantly higher than in trigeminal neuralgia, and this study does not support the positive results of the study of Ford et al. We consider the morbidity to be significant for the low rate of pain cessation, making this procedure less attractive even for the more severely affected subgroup of patients.

  6. Radiosurgery for the treatment of spinal lung metastases.

    PubMed

    Gerszten, Peter C; Burton, Steven A; Belani, Chandra P; Ramalingam, Suresh; Friedland, David M; Ozhasoglu, Cihat; Quinn, Annette E; McCue, Kevin J; Welch, William C

    2006-12-01

    Spinal metastases are a common source of pain as well as neurologic deficit in patients with lung cancer. Metastases from lung cancer traditionally have been believed to be relatively responsive to radiation therapy. However, conventional external beam radiotherapy lacks the precision to allow delivery of large single-fraction doses of radiation and simultaneously limit the dose to radiosensitive structures such as the spinal cord. The current study evaluated the efficacy of single-fraction radiosurgery for the treatment of spinal lung cancer metastases. In the current prospective cohort evaluation, 87 lung cancer metastases to the spine in 77 patients were treated with a single-fraction radiosurgery technique with a follow-up period of 6 to 40 months (median, 12 months). The indication for radiosurgery treatment was pain in 73 cases, as a primary treatment modality in 7 cases, for radiographic tumor progression in 4 cases, and for progressive neurologic deficit in 3 cases. Tumor volume ranged from 0.2 to 264 cm(3) (mean, 25.7 cm(3)). The maximum tumor dose was maintained at 15 to 25 grays (Gy) (mean, 20 Gy; median, 20 Gy). No radiation-induced toxicity occurred during the follow-up period. Long-term axial and radicular pain improvement occurred in 65 of 73 patients (89%) who were treated primarily for pain. Long-term radiographic tumor control was observed in all patients who underwent radiosurgery as their primary treatment modality or for radiographic tumor progression. Spinal radiosurgery was found to be feasible, safe, and clinically effective for the treatment of spinal metastases from lung cancer. The results of the current study indicate the potential of radiosurgery in the treatment of patients with spinal lung metastases, especially those with solitary sites of spine involvement, to improve long-term palliation. (c) 2006 American Cancer Society.

  7. Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy.

    PubMed

    Inoue, Hiroshi K; Nakajima, Atsushi; Sato, Hiro; Noda, Shin-Ei; Saitoh, Jun-Ichi; Suzuki, Yoshiyuki

    2015-03-01

    Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy.

  8. Image Fusion for Radiosurgery, Neurosurgery and Hypofractionated Radiotherapy

    PubMed Central

    Nakajima, Atsushi; Sato, Hiro; Noda, Shin-ei; Saitoh, Jun-ichi; Suzuki, Yoshiyuki

    2015-01-01

    Precise target detection is essential for radiosurgery, neurosurgery and hypofractionated radiotherapy because treatment results and complication rates are related to accuracy of the target definition. In skull base tumors and tumors around the optic pathways, exact anatomical evaluation of cranial nerves are important to avoid adverse effects on these structures close to lesions. Three-dimensional analyses of structures obtained with MR heavy T2-images and image fusion with CT thin-sliced sections are desirable to evaluate fine structures during radiosurgery and microsurgery. In vascular lesions, angiography is most important for evaluations of whole structures from feeder to drainer, shunt, blood flow and risk factors of bleeding. However, exact sites and surrounding structures in the brain are not shown on angiography. True image fusions of angiography, MR images and CT on axial planes are ideal for precise target definition. In malignant tumors, especially recurrent head and neck tumors, biologically active areas of recurrent tumors are main targets of radiosurgery. PET scan is useful for quantitative evaluation of recurrences. However, the examination is not always available at the time of radiosurgery. Image fusion of MR diffusion images with CT is always available during radiosurgery and useful for the detection of recurrent lesions. All images are fused and registered on thin sliced CT sections and exactly demarcated targets are planned for treatment. Follow-up images are also able to register on this CT. Exact target changes, including volume, are possible in this fusion system. The purpose of this review is to describe the usefulness of image fusion for 1) skull base, 2) vascular, 3) recurrent target detection, and 4) follow-up analyses in radiosurgery, neurosurgery and hypofractionated radiotherapy. PMID:26180676

  9. Penetration tests to study the mechanical tribological properties of chisel type knife

    NASA Astrophysics Data System (ADS)

    Vlăduţoiu, L.; Chişiu, G.; Andrei, T.; Predescu, A.; Muraru, C.; Vlăduţ, V.

    2017-02-01

    The goal of this study was to analyze the behaviour of chisel knife type penetration in a certain type of sand. A series of penetration tests were carried out with chisel knife type, the answer to penetration depending mainly on nature, shape, size of knife and operating parameters such as speed, depth and working conditions. Tests were conducted in work conditions with wet sand and dry sand and determined force of resistance to penetration of the chisel knife type to a certain depth.

  10. 10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

  11. 10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

  12. 10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

  13. 10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

  14. Dose calculation accuracy of the Monte Carlo algorithm for CyberKnife compared with other commercially available dose calculation algorithms.

    PubMed

    Sharma, Subhash; Ott, Joseph; Williams, Jamone; Dickow, Danny

    2011-01-01

    Monte Carlo dose calculation algorithms have the potential for greater accuracy than traditional model-based algorithms. This enhanced accuracy is particularly evident in regions of lateral scatter disequilibrium, which can develop during treatments incorporating small field sizes and low-density tissue. A heterogeneous slab phantom was used to evaluate the accuracy of several commercially available dose calculation algorithms, including Monte Carlo dose calculation for CyberKnife, Analytical Anisotropic Algorithm and Pencil Beam convolution for the Eclipse planning system, and convolution-superposition for the Xio planning system. The phantom accommodated slabs of varying density; comparisons between planned and measured dose distributions were accomplished with radiochromic film. The Monte Carlo algorithm provided the most accurate comparison between planned and measured dose distributions. In each phantom irradiation, the Monte Carlo predictions resulted in gamma analysis comparisons >97%, using acceptance criteria of 3% dose and 3-mm distance to agreement. In general, the gamma analysis comparisons for the other algorithms were <95%. The Monte Carlo dose calculation algorithm for CyberKnife provides more accurate dose distribution calculations in regions of lateral electron disequilibrium than commercially available model-based algorithms. This is primarily because of the ability of Monte Carlo algorithms to implicitly account for tissue heterogeneities, density scaling functions; and/or effective depth correction factors are not required. Copyright © 2011 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

  15. Super-resolved terahertz microscopy by knife-edge scan

    NASA Astrophysics Data System (ADS)

    Giliberti, V.; Flammini, M.; Ciano, C.; Pontecorvo, E.; Del Re, E.; Ortolani, M.

    2017-08-01

    We present a compact, all solid-state THz confocal microscope operating at 0.30 THz that achieves super-resolution by using the knife-edge scan approach. In the final reconstructed image, a lateral resolution of 60 μm ≍ λ/17 is demonstrated when the knife-edge is deep in the near-field of the sample surface. When the knife-edge is lifted up to λ/4 from the sample surface, a certain degree of super-resolution is maintained with a resolution of 0.4 mm, i.e. more than a factor 2 if compared to the diffraction-limited scheme. The present results open an interesting path towards super-resolved imaging with in-depth information that would be peculiar to THz microscopy systems.

  16. 10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

  17. 10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

  18. 10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

  19. 10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

  20. 10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

  1. Stereotactic radiosurgery for multiple brain metastases

    NASA Astrophysics Data System (ADS)

    Lee, Anna; (Josh Yamada, Yoshiya

    2017-01-01

    Whole brain radiation therapy has been the traditional treatment of choice for patients with multiple brain metastases. Although stereotactic radiosurgery is widely accepted for the management to up to 4 brain metastases, its use is still controversial in cases of 5 or more brain metastases. Randomized trials have suggested that stereotactic radiosurgery alone is appropriate in up to 4 metastases without concomitant whole brain radiation. Level 1 evidence also suggests that withholding whole brain radiation may also reduce the impact of radiation on neurocognitive function and also may even offer a survival advantage. A recent analysis of a large multicentre prospective database has suggested that there are no differences in outcomes such as the likelihood of new metastasis or leptomeningeal disease in cases of 2-10 brain metastases, nor in overall survival. Hence in the era of prolonged survival with stage IV cancer, stereotactic radiosurgery is a reasonable alternative to whole brain radiation in order to minimize the impact of treatment upon quality of life without sacrificing overall survival.

  2. Stereotactic Radiosurgery and Fractionated Stereotactic Radiation Therapy for the Treatment of Uveal Melanoma

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yazici, Gozde; Kiratli, Hayyam; Ozyigit, Gokhan

    Purpose: To evaluate treatment results of stereotactic radiosurgery or fractionated stereotactic radiation therapy (SRS/FSRT) for uveal melanoma. Methods and Materials: We retrospectively evaluated 181 patients with 182 uveal melanomas receiving SRS/FSRT between 2007 and 2013. Treatment was administered with CyberKnife. Results: According to Collaborative Ocular Melanoma Study criteria, tumor size was small in 1%, medium in 49.5%, and large in 49.5% of the patients. Seventy-one tumors received <45 Gy, and 111 received ≥45 Gy. Median follow-up time was 24 months. Complete and partial response was observed in 8 and 104 eyes, respectively. The rate of 5-year overall survival was 98%, disease-free survival 57%,more » local recurrence-free survival 73%, distant metastasis-free survival 69%, and enucleation-free survival 73%. There was a significant correlation between tumor size and disease-free survival, SRS/FSRT dose and enucleation-free survival; and both were prognostic for local recurrence-free survival. Enucleation was performed in 41 eyes owing to progression in 26 and complications in 11. Conclusions: The radiation therapy dose is of great importance for local control and eye retention; the best treatment outcome was achieved using ≥45 Gy in 3 fractions.« less

  3. Diamond knife-assisted deep anterior lamellar keratoplasty to manage keratoconus.

    PubMed

    Vajpayee, Rasik B; Maharana, Prafulla K; Sharma, Namrata; Agarwal, Tushar; Jhanji, Vishal

    2014-02-01

    To evaluate the outcomes of a new surgical technique, diamond knife-assisted deep anterior lamellar keratoplasty (DALK), and compare its visual and refractive results with big-bubble DALK in cases of keratoconus. Tertiary eyecare hospital. Comparative case series. The visual and surgical outcomes of diamond knife-assisted DALK were compared with those of successful big-bubble DALK. Diamond knife-assisted DALK was performed in 19 eyes and big-bubble DALK, in 11 eyes. All surgeries were completed successfully. No intraoperative or postoperative complications occurred with diamond knife-assisted DALK. Six months after diamond knife-assisted DALK, the mean corrected distance visual acuity (CDVA) improved significantly from 1.87 logMAR ± 0.22 (SD) to 0.23 ± 0.06 logMAR, the mean keratometry improved from 65.99 ± 8.86 diopters (D) to 45.13 ± 1.16 D, and the mean keratometric cylinder improved from 7.99 ± 3.81 D to 2.87 ± 0.59 D (all P=.005). Postoperatively, the mean refractive astigmatism was 2.55 ± 0.49 D and the mean spherical equivalent was -1.97 ± 0.56 D. The mean logMAR CDVA (P = .06), postoperative keratometry (P=.64), refractive cylinder (P=.63), and endothelial cell loss (P=.11) were comparable between diamond knife-assisted DALK and big-bubble DALK. Diamond knife-assisted DALK was effective and predictable as a surgical technique for management of keratoconus cases. This technique has the potential to offer visual and refractive outcomes comparable to those of big-bubble DALK. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2013 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  4. Multileaf collimator-based linear accelerator radiosurgery: five-year efficiency analysis.

    PubMed

    Lawson, Joshua D; Fox, Tim; Waller, Anthony F; Davis, Lawrence; Crocker, Ian

    2009-03-01

    In 1989, Emory University initiated a linear accelerator (linac) radiosurgery program using circular collimators. In 2001, the program converted to a multileaf collimator. Since then, the treatment parameters of each patient have been stored in the record-and-verify system. Three major changes have occurred in the radiosurgery program in the past 6 years: in 2002, treatment was changed from static conformal beams to dynamic conformal arc (DCA) therapy, and all patients were imaged before treatment. Beginning in 2005, a linac was used, with the opportunity to treat at higher dose rates (600-1,000 monitor units/min). The aim of this study was to analyze the time required to deliver radiosurgery and the factors affecting treatment delivery. Benchmark data are provided for centers contemplating initiating linac radiosurgery programs. Custom software was developed to mine the record-and-verify system database and automatically perform a chart review on patients who underwent stereotactic radiosurgery from March 2001 to October 2006. The software extracted 510 patients who underwent stereotactic radiosurgery, and the following information was recorded for each patient: treatment technique, treatment time (from initiation of imaging, if done, to completion of therapy), number of isocenters, number of fields, total monitor units, and dose rate. Of the 510 patients, 395 were treated with DCA therapy and 115 with static conformal beams. The average number of isocenters treated was 1.06 (range, 1-4). The average times to deliver treatment were 24.1 minutes for patients who underwent DCA therapy and 19.3 minutes for those treated with static conformal beams, reflecting the lack of imaging in the latter patients. Eighty percent of patients were treated in <30 minutes. For the patients who underwent DCA therapy, the times required to treat 1, 2, 3, and 4 isocenters were 23.9, 24.8, 33.1, and 37.8 minutes, respectively. Average beam-on time for these patients was 11.4 minutes

  5. WE-DE-BRA-11: A Study of Motion Tracking Accuracy of Robotic Radiosurgery Using a Novel CCD Camera Based End-To-End Test System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, L; M Yang, Y; Nelson, B

    Purpose: A novel end-to-end test system using a CCD camera and a scintillator based phantom (XRV-124, Logos Systems Int’l) capable of measuring the beam-by-beam delivery accuracy of Robotic Radiosurgery (CyberKnife) was developed and reported in our previous work. This work investigates its application in assessing the motion tracking (Synchrony) accuracy for CyberKnife. Methods: A QA plan with Anterior and Lateral beams (with 4 different collimator sizes) was created (Multiplan v5.3) for the XRV-124 phantom. The phantom was placed on a motion platform (superior and inferior movement), and the plans were delivered on the CyberKnife M6 system using four motion patterns:more » static, Sine- wave, Sine with 15° phase shift, and a patient breathing pattern composed of 2cm maximum motion with 4 second breathing cycle. Under integral recording mode, the time-averaged beam vectors (X, Y, Z) were measured by the phantom and compared with static delivery. In dynamic recording mode, the beam spots were recorded at a rate of 10 frames/second. The beam vector deviation from average position was evaluated against the various breathing patterns. Results: The average beam position of the six deliveries with no motion and three deliveries with Synchrony tracking on ideal motion (sinewave without phase shift) all agree within −0.03±0.00 mm, 0.10±0.04, and 0.04±0.03 in the X, Y, and X directions. Radiation beam width (FWHM) variations are within ±0.03 mm. Dynamic video record showed submillimeter tracking stability for both regular and irregular breathing pattern; however the tracking error up to 3.5 mm was observed when a 15 degree phase shift was introduced. Conclusion: The XRV-124 system is able to provide 3D and 4D targeting accuracy for CyberKnife delivery with Synchrony. The experimental results showed sub-millimeter delivery in phantom with excellent correlation in target to breathing motion. The accuracy was degraded when irregular motion and phase shift was

  6. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

  7. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 1 2011-01-01 2011-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

  8. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

  9. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

  10. Usefulness of IT knife nano for endoscopic submucosal dissection of large colo-rectal lesions.

    PubMed

    Suzuki, T; Hara, T; Kitagawa, Y; Yamaguchi, T

    2016-01-01

    Endoscopic submucosal dissection (ESD) is currently widely conducted for the treatment of early gastrointestinal -cancers. Due to the characteristic anatomy of the large intestine, needle- tip type devices such as Dual knife are mainly used in colorectal ESD. On the other hand, the non- needle-tip type IT knife is a unique device with an insulated tip, and has been reported to be safe, efficacious and speedy when used in gastric ESD. A new model of IT knife, IT knife nano, anticipated to be useful for esophageal and colorectal ESD has become available, but its usefulness has not been reported. Therefore, we performed this study to evaluate the usefulness of IT knife nano for ESD of large colorectal lesions. Previous studies have shown that a tumor size of 40 mm or above significantly prolongs treatment time and is a factor of treatment difficulty. We selected colorectal lesions of 40 mm and above, and compared 32 lesions treated with Dual knife alone before IT knife nano was available (No-IT group) and 40 cases treated with IT knife nano as a second knife after IT knife nano became available (IT group). We assessed en bloc resection rate, complete en bloc resection rate, complication rate and treatment time. The en bloc resection rates in No-IT group and IT group were 100% and 97.5%, respectively, with no significant difference. The respective median treatment time was 70 min and 51 min, and was significantly shortened in IT group (P < 0.05). The respective rates of procedure- related perforation were 3.1% and 0% ; in IT group suggesting a tendency of reduced incidence. Use of IT knife nano in ESD for large colorectal -lesions achieves the same levels of efficacy and safety as conventional device, with the additional merit of shortening treatment time. © Acta Gastro-Enterologica Belgica.

  11. Endoscopic treatment of Zenker's diverticulum with the stag beetle knife (sb knife) - feasibility and follow-up.

    PubMed

    Goelder, S K; Brueckner, J; Messmann, H

    2016-10-01

    Flexible endoscopic treatment of symptomatic Zenker's diverticulum (ZD) is an established treatment option. This study reports the first large cohort of ZD patients treated with the stag beetle knife (sb knife, a new scissor-like device) regarding feasibility, safety, and sustainability of mucomyotomy using this technique. From August 2013 to January 2016, n = 52 patients (pts) were treated at Klinikum Augsburg, a tertiary referral center, with the sb knife junior or standard. For stability and safety, the septum is fixed with a soft overtube before intervention. Symptoms were analyzed before and at 1 and 6 months past intervention using an extensive questionnaire of dysphagia, odynophagia, regurgitation, chronic cough, state of health, and complications. The mean size of ZD was 3 cm (1-5 cm). Forty-seven out of 52 (90.4%) patients received one treatment session. The mean procedure time was 32 min (18-60 min). In 10 procedures (17%), a clip was placed at the bottom of the resection line. No major complications (e.g., perforation, mediastinitis) occurred. Five patients (9.6%) required a second treatment after a mean of 7 months (3-13) due to symptomatic recurrence. One patient was lost to further follow-up after one month with no or rare complaints. One patient had a third treatment (1.9%) without complications. During a mean follow-up of 16 months (2-31), the dysphagia score improved from 2 (1-4) prior of treatment to 1 (0-4), odynophagia, regurgitation, and chronic cough were no longer reported in the asymptomatic patients at all. Flexible endoscopic treatment of ZD with the sb knife and overtube is effective, safe, and has lasting effects with a relatively low recurrence rate.

  12. International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cox, Brett W., E-mail: coxb@mskcc.org; Spratt, Daniel E.; Lovelock, Michael

    2012-08-01

    Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE)more » with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive

  13. SU-E-J-06: Additional Imaging Guidance Dose to Patient Organs Resulting From X-Ray Tubes Used in CyberKnife Image Guidance System

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sullivan, A; Ding, G

    Purpose: The use of image-guided radiation therapy (IGRT) has become increasingly common, but the additional radiation exposure resulting from repeated image guidance procedures raises concerns. Although there are many studies reporting imaging dose from different image guidance devices, imaging dose for the CyberKnife Robotic Radiosurgery System is not available. This study provides estimated organ doses resulting from image guidance procedures on the CyberKnife system. Methods: Commercially available Monte Carlo software, PCXMC, was used to calculate average organ doses resulting from x-ray tubes used in the CyberKnife system. There are seven imaging protocols with kVp ranging from 60 – 120 kVmore » and 15 mAs for treatment sites in the Cranium, Head and Neck, Thorax, and Abdomen. The output of each image protocol was measured at treatment isocenter. For each site and protocol, Adult body sizes ranging from anorexic to extremely obese were simulated since organ dose depends on patient size. Doses for all organs within the imaging field-of-view of each site were calculated for a single image acquisition from both of the orthogonal x-ray tubes. Results: Average organ doses were <1.0 mGy for every treatment site and imaging protocol. For a given organ, dose increases as kV increases or body size decreases. Higher doses are typically reported for skeletal components, such as the skull, ribs, or clavicles, than for softtissue organs. Typical organ doses due to a single exposure are estimated as 0.23 mGy to the brain, 0.29 mGy to the heart, 0.08 mGy to the kidneys, etc., depending on the imaging protocol and site. Conclusion: The organ doses vary with treatment site, imaging protocol and patient size. Although the organ dose from a single image acquisition resulting from two orthogonal beams is generally insignificant, the sum of repeated image acquisitions (>100) could reach 10–20 cGy for a typical treatment fraction.« less

  14. Knife River Indian Villages National Historic Site: Teacher's Guide.

    ERIC Educational Resources Information Center

    National Park Service (Dept. of Interior), Washington, DC. National Register of Historic Places.

    This guide provides history and social studies teachers, at all grade levels, with information and activities about the American Indians of the Northern Plains who lived in the area of the Knife River where it enters the Missouri River. Located in what is now North Dakota, this area is the Knife River Indian Villages National Historic Site. The…

  15. Longitudinal assessment of quality of life and audiometric test outcomes in vestibular schwannoma patients treated with gamma knife surgery.

    PubMed

    Park, Sean S; Grills, Inga Siiner; Bojrab, Dennis; Pieper, Daniel; Kartush, Jack; Maitz, Ann; Martin, Arturo; Perez, Evelyn; Hahn, Yoav; Ye, Hong; Martinez, Alvaro; Chen, Peter

    2011-06-01

    To prospectively assess the quality of life (QOL) and hearing acuity in vestibular schwannoma (VS) patients after gamma knife surgery (GKS). Fifty-nine VS patients. GKS. Prospective follow-up algorithm included 36-item Short Form Health Survey (SF-36), Hearing Handicap Inventory (HHI), Dizziness Handicap Inventory (DHI), Tinnitus Handicap Inventory (THI), pure-tone average, and speech discrimination hearing scores (Gardner-Robertson and American Academy of Otolaryngology), performed before and after GKS at 1-, 3-, 6-, 12-, and 18-month posttreatment intervals. From December 2006 to November 2008, 59 VS patients were treated with a median follow-up of 15 months. At baseline, mean scores for SF-36, HHI, DHI, and THI were 73, 37, 17, and 23, respectively. Median baseline Gardner-Robertson and American Academy of Otolaryngology hearing acuity scores were 2 and B, respectively. No significant decline in SF-36 health survey was noted after GKS. Mean SF-36 score at baseline was 73, compared with a range of 70 to 77 at predetermined posttreatment intervals. Similarly, no significant changes in DHI, HHI, and THI were noted. Approximately 47% of patients with baseline serviceable hearing maintained serviceable hearing at 12 months. Significant acute and chronic worsening in hearing acuity were noted at 1 and 18 months, respectively. No correlative decline in QOL was noted as assessed by SF-36 or HHI. No significant decline in global QOL occurred after GKS with relatively short follow-up and approximately 50% survey completion. When discussing therapy options with VS patients, anticipated treatment-related QOL outcomes should be considered.

  16. [Development of external quality control protocol for CyberKnife beams dosimetry: preliminary tests multicentre].

    PubMed

    Guinement, L; Marchesi, V; Veres, A; Lacornerie, T; Buchheit, I; Peiffert, D

    2013-01-01

    To develop an external quality control procedure for CyberKnife(®) beams. This work conducted in Nancy, has included a test protocol initially drawn by the medical physicist of Nancy and Lille in collaboration with Equal-Estro Laboratory. A head and neck anthropomorphic phantom and a water-equivalent homogeneous cubic plastic test-object, so-called "MiniCube", have been used. Powder and solid thermoluminescent dosimeters as well as radiochromic films have been used to perform absolute and relative dose studies, respectively. The comparison between doses calculated by Multiplan treatment planning system and measured doses have been studied in absolute dose. The dose distributions measured with films and treatment planning system calculations have been compared via the gamma function, configured with different tolerance criteria. This work allowed, via solid thermoluminescent dosimeter measurements, verifying the beam reliability with a reproducibility of 1.7 %. The absolute dose measured in the phantom irradiated by the seven participating centres has shown an error inferior to the standard tolerance limits (± 5 %), for most of participating centres. The relative dose measurements performed at Nancy and by the Equal-Estro laboratory allowed defining the most adequate parameters for gamma index (5 %/2mm--with at least 95 % of pixels satisfying acceptability criteria: γ<1). These parameters should be independent of the film analysis software. This work allowed defining a dosimetric external quality control for CyberKnife(®) systems, based on a reproducible irradiation plan through measurements performed with thermoluminescent dosimeters and radiochromic films. This protocol should be validated by a new series of measurement and taking into account the lessons of this work. Copyright © 2013 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

  17. Endoscopic treatment for pancreatic diseases: Needle-knife-guided cannulation via the minor papilla

    PubMed Central

    Wang, Wei; Gong, Biao; Jiang, Wei-Song; Liu, Lei; Bielike, Kouken; Xv, Bin; Wu, Yun-Lin

    2015-01-01

    AIM: To determine the efficacy and safety of meticulous cannulation by needle-knife. METHODS: Three needle-knife procedures were used to facilitate cannulation in cases when standard cannulation techniques failed. A total of 104 cannulations via the minor papilla attempted in 74 patients at our center between January 2008 and June 2014 were retrospectively reviewed. RESULTS: Standard methods were successful in 79 cannulations. Of the 25 cannulations that could not be performed by standard methods, 19 were performed by needle-knife, while 17 (89.5%) were successful. Needle-knife use improved the success rate of cannulation [76.0%, 79/104 vs 92.3%, (79 + 17)/104; P = 0.001]. When the 6 cases not appropriate for needle-knife cannulation were excluded, the success rate was improved further (80.6%, 79/98 vs 98.0%, 96/98; P = 0.000). There were no significant differences in the rates of post-endoscopic retrograde cholangiopancreatography adverse events between the group using standard methods alone and the group using needle-knife after failure of standard methods (4.7% vs 10.5%, P = 0.301). CONCLUSION: The needle-knife procedure may be an alternative method for improving the success rate of cannulation via the minor papilla, particularly when standard cannulation has failed. PMID:26019460

  18. Endoscopic treatment for pancreatic diseases: Needle-knife-guided cannulation via the minor papilla.

    PubMed

    Wang, Wei; Gong, Biao; Jiang, Wei-Song; Liu, Lei; Bielike, Kouken; Xv, Bin; Wu, Yun-Lin

    2015-05-21

    To determine the efficacy and safety of meticulous cannulation by needle-knife. Three needle-knife procedures were used to facilitate cannulation in cases when standard cannulation techniques failed. A total of 104 cannulations via the minor papilla attempted in 74 patients at our center between January 2008 and June 2014 were retrospectively reviewed. Standard methods were successful in 79 cannulations. Of the 25 cannulations that could not be performed by standard methods, 19 were performed by needle-knife, while 17 (89.5%) were successful. Needle-knife use improved the success rate of cannulation [76.0%, 79/104 vs 92.3%, (79 + 17)/104; P = 0.001]. When the 6 cases not appropriate for needle-knife cannulation were excluded, the success rate was improved further (80.6%, 79/98 vs 98.0%, 96/98; P = 0.000). There were no significant differences in the rates of post-endoscopic retrograde cholangiopancreatography adverse events between the group using standard methods alone and the group using needle-knife after failure of standard methods (4.7% vs 10.5%, P = 0.301). The needle-knife procedure may be an alternative method for improving the success rate of cannulation via the minor papilla, particularly when standard cannulation has failed.

  19. Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wen, N., E-mail: nwen1@hfhs.org; Snyder, K. C.; Qin, Y.

    2016-05-15

    Purpose: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. Methods: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, “snap-shot” planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. Results: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2more » mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. Conclusions: The authors’ experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.« less

  20. Development of an air knife to remove seed coat fragments during lint cleaning

    USDA-ARS?s Scientific Manuscript database

    An air knife is a tool commonly used to blow off debris in a manufacturing line. The knife may also be used to break the attachment force between a lint cleaner saw and a seed coat fragment (SCF) with attached fiber, and remove them. Work continued on evaluating an auxiliary air knife mounted on t...

  1. High resolution ion chamber array delivery quality assurance for robotic radiosurgery: Commissioning and validation.

    PubMed

    Blanck, Oliver; Masi, Laura; Chan, Mark K H; Adamczyk, Sebastian; Albrecht, Christian; Damme, Marie-Christin; Loutfi-Krauss, Britta; Alraun, Manfred; Fehr, Roman; Ramm, Ulla; Siebert, Frank-Andre; Stelljes, Tenzin Sonam; Poppinga, Daniela; Poppe, Björn

    2016-06-01

    High precision radiosurgery demands comprehensive delivery-quality-assurance techniques. The use of a liquid-filled ion-chamber-array for robotic-radiosurgery delivery-quality-assurance was investigated and validated using several test scenarios and routine patient plans. Preliminary evaluation consisted of beam profile validation and analysis of source-detector-distance and beam-incidence-angle response dependence. The delivery-quality-assurance analysis is performed in four steps: (1) Array-to-plan registration, (2) Evaluation with standard Gamma-Index criteria (local-dose-difference⩽2%, distance-to-agreement⩽2mm, pass-rate⩾90%), (3) Dose profile alignment and dose distribution shift until maximum pass-rate is found, and (4) Final evaluation with 1mm distance-to-agreement criterion. Test scenarios consisted of intended phantom misalignments, dose miscalibrations, and undelivered Monitor Units. Preliminary method validation was performed on 55 clinical plans in five institutions. The 1000SRS profile measurements showed sufficient agreement compared with a microDiamond detector for all collimator sizes. The relative response changes can be up to 2.2% per 10cm source-detector-distance change, but remains within 1% for the clinically relevant source-detector-distance range. Planned and measured dose under different beam-incidence-angles showed deviations below 1% for angles between 0° and 80°. Small-intended errors were detected by 1mm distance-to-agreement criterion while 2mm criteria failed to reveal some of these deviations. All analyzed delivery-quality-assurance clinical patient plans were within our tight tolerance criteria. We demonstrated that a high-resolution liquid-filled ion-chamber-array can be suitable for robotic radiosurgery delivery-quality-assurance and that small errors can be detected with tight distance-to-agreement criterion. Further improvement may come from beam specific correction for incidence angle and source

  2. A case-matched study of stereotactic radiosurgery for patients with brain metastases: comparing treatment results for those with versus without neurological symptoms.

    PubMed

    Koiso, Takao; Yamamoto, Masaaki; Kawabe, Takuya; Watanabe, Shinya; Sato, Yasunori; Higuchi, Yoshinori; Yamamoto, Tetsuya; Matsumura, Akira; Kasuya, Hidetoshi; Barfod, Bierta E

    2016-12-01

    We aimed to reappraise whether post-stereotactic radiosurgery (SRS) results for brain metastases differ between patients with and without neurological symptoms. This was an institutional review board-approved, retrospective cohort study using our prospectively accumulated database including 2825 consecutive BM patients undergoing gamma knife SRS alone during the 15-year period since July 1998. The 2825 patients were divided into two groups; neurologically asymptomatic [group A, 1374 patients (48.6 %)] and neurologically symptomatic [group B, 1451 (51.4 %)]. Because there was considerable bias in pre-SRS clinical factors between groups A and B, a case-matched study was conducted. Ultimately, 1644 patients (822 in each group) were selected. The standard Kaplan-Meier method was used to determine post-SRS survival. Competing risk analysis was applied to estimate cumulative incidences of neurological death, neurological deterioration, local recurrence, re-SRS for new lesions and SRS-induced complications. Post-SRS median survival times (MSTs) did not differ between the two groups; 7.8 months in group A versus 7.4 months in group B patients (HR 1.064, 95 % CI 0.963-1.177, p = 0.22). However, cumulative incidences of neurological death (HR 1.637, 95 % CI 1.174-2.281, p = 0.0036) and neurological deterioration (HR 1.425, 95 % CI 1.073-1.894, p = 0.014) were significantly lower in the group A than in the group B patients. Neurologically asymptomatic patients undergoing SRS for BM had better results than symptomatic patients in terms of both maintenance of good neurological state and prolonged neurological survival. Thus, we conclude that screening computed tomography/magnetic resonance imaging is highly beneficial for managing cancer patients.

  3. Predictors of Individual Tumor Local Control After Stereotactic Radiosurgery for Non-Small Cell Lung Cancer Brain Metastases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Garsa, Adam A.; Badiyan, Shahed N.; DeWees, Todd

    2014-10-01

    Purpose: To evaluate local control rates and predictors of individual tumor local control for brain metastases from non-small cell lung cancer (NSCLC) treated with stereotactic radiosurgery (SRS). Methods and Materials: Between June 1998 and May 2011, 401 brain metastases in 228 patients were treated with Gamma Knife single-fraction SRS. Local failure was defined as an increase in lesion size after SRS. Local control was estimated using the Kaplan-Meier method. The Cox proportional hazards model was used for univariate and multivariate analysis. Receiver operating characteristic analysis was used to identify an optimal cutpoint for conformality index relative to local control. Amore » P value <.05 was considered statistically significant. Results: Median age was 60 years (range, 27-84 years). There were 66 cerebellar metastases (16%) and 335 supratentorial metastases (84%). The median prescription dose was 20 Gy (range, 14-24 Gy). Median overall survival from time of SRS was 12.1 months. The estimated local control at 12 months was 74%. On multivariate analysis, cerebellar location (hazard ratio [HR] 1.94, P=.009), larger tumor volume (HR 1.09, P<.001), and lower conformality (HR 0.700, P=.044) were significant independent predictors of local failure. Conformality index cutpoints of 1.4-1.9 were predictive of local control, whereas a cutpoint of 1.75 was the most predictive (P=.001). The adjusted Kaplan-Meier 1-year local control for conformality index ≥1.75 was 84% versus 69% for conformality index <1.75, controlling for tumor volume and location. The 1-year adjusted local control for cerebellar lesions was 60%, compared with 77% for supratentorial lesions, controlling for tumor volume and conformality index. Conclusions: Cerebellar tumor location, lower conformality index, and larger tumor volume were significant independent predictors of local failure after SRS for brain metastases from NSCLC. These results warrant further investigation in a

  4. Palliation of Postintubation Tracheal Stenosis Using Insulation-Tipped Diathermic Knife 2: A Case Report

    PubMed Central

    Yoon, Seon Bin; Park, Yong Won; Cheon, Mi Ju; Koh, Young Min; Park, Sanghoon; Kim, Se Joong; Lee, Seung Hyeun

    2015-01-01

    Objective To report the first case of using the insulation-tipped diathermic knife 2 (IT knife-2) for the treatment of postintubation tracheal stenosis. Clinical Presentation and Intervention A 71-year-old female patient with a history of endotracheal intubation 3 years earlier presented with throat discomfort, gross wheezing and dyspnea. Chest imaging and bronchoscopy demonstrated a strand-like tracheal stenosis in the upper trachea. The IT knife-2 was used to treat the patient and the lesion was palliated without complication. Conclusion This case was successfully treated with the IT knife-2 and thus implies a potential usefulness of the IT knife-2 as a new modality for bronchoscopic intervention. PMID:26390388

  5. Charged-particle stereotactic radiosurgery

    NASA Astrophysics Data System (ADS)

    Lyman, John T.; Fabrikant, Jacob I.; Frankel, Kenneth A.

    1985-05-01

    Charged-particle stereotactic radiosurgery is the technique of using accelerated atomic nuclei for the irradiation of a small volume target to a high dose in a short time interval. This is contrasted with conventional radiotherapy where large volumes are treated with many small fractions of photon or electron radiation over a multi-week period. The helium-ion beam used for charged-particle stereotactic radiosurgery at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron is described. This beam is being used for the treatment of inoperable, deep, intracranial arteriovenous malformations (AVMs). Intracranial AVMs are collections of abnormal blood vessels in the brain that may represent a failure of vessels to mature properly and after a long period of slow growth they may produce clinically recognizable neurological symptoms. Based on our experience using narrow beams of helium ions for stereotactic radiosurgical treatment of AVM patients, the characteristics of the treatments are described. Improvements to the technique which are possible by the use of other charged particle beams are discussed.

  6. Objective assessment of knife sharpness over a working day cutting meat.

    PubMed

    Savescu, Adriana; Cuny-Guerrier, Aude; Wild, Pascal; Reno, Gilles; Aublet-Cuvelier, Agnès; Claudon, Laurent

    2018-04-01

    Knife sharpness is one of multiple factors involved in musculoskeletal disorders in industrial meat cutting. The aim of this study was to objectively evaluate, in real working situations, how knife sharpness changed over a working day cutting meat, and to analyse the impact of sharpening, steeling and meat-cutting activities on these variations. Twenty-two meat-cutting workers from three different companies participated in the study. The methods included measurements of knife sharpness in relation to real work situations and consideration of the way meat-cutting and sharpening operations were organised. Results showed that the type of meat-cutting activities, the steeling strategy adopted by the worker, including the types of tool used, and the overall organisation of the sharpening task all had a significant influence on how knife sharpness evolved over a 2-h period and over an entire working day. To improve MSD prevention, sharpening and steeling operations should not be considered as independent activities, but taken into account as a continuity of working actions. Appropriate assessment of knife sharpness by meat cutters affects how they organise meat-cutting and sharpening tasks. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. WE-G-BRD-08: End-To-End Targeting Accuracy of the Gamma Knife for Trigeminal Neuralgia

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brezovich, I; Wu, X; Duan, J

    2014-06-15

    Purpose: Current QA procedures verify accuracy of individual equipment parameters, but may not include CT and MRI localizers. This study uses an end-to-end approach to measure the overall targeting errors in individual patients previously treated for trigeminal neuralgia. Methods: The trigeminal nerve is simulated by a 3 mm long, 3.175 mm (1/8 inch) diameter MRI contrast-filled cavity embedded within a PMMA plastic capsule. The capsule is positioned within the head frame such that the cavity position matches the Gamma Knife coordinates of 10 previously treated patients. Gafchromic EBT2 film is placed at the center of the cavity in coronal andmore » sagittal orientations. The films are marked with a pin prick to identify the cavity center. Treatments are planned for delivery with 4 mm collimators using MRI and CT scans acquired with the clinical localizer boxes and acquisition protocols. Coordinates of shots are chosen so that the cavity is centered within the 50% isodose volume. Following irradiation, the films are scanned and analyzed. Targeting errors are defined as the distance between the pin prick and the centroid of the 50% isodose line. Results: Averaged over 10 patient simulations, targeting errors along the x, y and z coordinates (patient left-to-right, posterior-anterior, head-to-foot) were, respectively, −0.060 +/− 0.363, −0.350 +/− 0.253, and 0.364 +/− 0.191 mm when MRI was used for treatment planning. Planning according to CT exhibited generally smaller errors, namely 0.109 +/− 0.167, −0.191 +/− 0.144, and 0.211 +/− 0.94 mm. The largest errors in MRI and CT planned treatments were, respectively, y = −0.761 and x = 0.428 mm. Conclusion: Unless patient motion or stronger MRI image distortion in actual treatments caused additional errors, all patients received the prescribed dose, i.e., the targeted section of the trig±eminal nerve was contained within the 50% isodose surface in all cases.« less

  8. SU-E-T-517: Investigation of Factors Contributing to Extracranial Radiation Doses From Leksell Gamma Knife

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kon, D; Kameda Medical Centre, Chiba, JP; Nakano, M

    2015-06-15

    Purpose The purpose of this study is to investigate dominant factors for doses to extracranial sites in treatment with Leksell Gamma Knife (LGK). Methods Monte Carlo simulation was implemented using EGS5 version 1.4.401. The simulation was divided into two major steps for the purpose of efficiency. As the first step, phase-space files were obtained at a scoring plane located just below patient-side surface of the collimator helmet of LGK. Scored particles were classified into three groups, primary, leakage and scatter, using their history information until their arrival to the scoring plane. Then classification was used at the following second stepmore » simulation to investigate which type of particle is dominant in the deposited energy at extra-cranial sites. In the second stage, a cylindrical phantom with a semisphere shaped head was modeled such that the geometrical center of the phantom’s head corresponds to the unit center point (UCP) of LGK. Scoring regions were arranged at 10 cm intervals from the UCP to 70 cm away on the central axis of the phantom. Energy deposition from each type of particles and location of interaction were recorded. Results The dominant factor of deposited energy depended on the collimator size. In the case of smaller collimator size, leakage was dominant. However, contribution of leakage was relatively small in the case of larger collimator size. The contribution of internal scatter varied with the distance from the UCP. In the proximal areas, internal scatter was dominant, whereas in the distal areas, particles interacting with machine components became dominant factor. Conclusion The Result of this study indicates that the dominant factor to dose to an extracranial site can vary with the distance from UCP and with collimator size. This means that the variation of this contribution must be considered for modeling of the extracranial dose especially in the distal area. This work was partly supported by the JSPS Core

  9. Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas.

    PubMed

    Tu, Albert; Gooderham, Peter; Mick, Paul; Westerberg, Brian; Toyota, Brian; Akagami, Ryojo

    2015-08-01

    Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation-treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients.

  10. Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas

    PubMed Central

    Tu, Albert; Gooderham, Peter; Mick, Paul; Westerberg, Brian; Toyota, Brian; Akagami, Ryojo

    2015-01-01

    Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation–treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients. PMID:26225318

  11. Endoscopic submucosal dissection for superficial esophageal neoplasms using the stag beetle knife.

    PubMed

    Fujinami, H; Hosokawa, A; Ogawa, K; Nishikawa, J; Kajiura, S; Ando, T; Ueda, A; Yoshita, H; Sugiyama, T

    2014-01-01

    Endoscopic submucosal dissection (ESD) is an accepted standard treatment for early gastric cancer but is not widely used in the esophagus because of technical difficulties. To increase the safety of esophageal ESD, we used a scissors-type device called the stag beetle (SB) knife. The aim of this study was to determine the efficacy and safety of ESD using the SB knife. We performed a single-center retrospective, uncontrolled trial. A total of 38 lesions were excised by ESD from 35 consecutive patients who were retrospectively divided into the following two groups according to the type of knife used to perform ESD: the hook knife (hook group) was used in 20 patients (21 lesions), and the SB knife (SB group) was used in 15 patients (17 lesions). We evaluated and compared the operative time, lesion size, en bloc resection rate, pathological margins free rate, and complication rate in both groups. The operative time was shorter in the SB group (median 70.0 minutes [interquartile range, 47.5-87.0]) than in the hook group (92.0 minutes [interquartile range, 63.0-114.0]) (P = 0.019), and the rate of complications in the SB group was 0% compared with 45.0% in the hook group (P = 0.004). However, the lesion size, en bloc resection rate, and pathological margins free rate did not differ significantly between the two groups. In conclusion, ESD using the SB knife was safer than that using a conventional knife for superficial esophageal neoplasms. © 2013 Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus.

  12. A Simple Approach to the Technical Aspects of Radiosurgery Treatments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prasad, S.C.; Bassano, D.A.; King, G.A.

    2015-01-15

    An approach to radiosurgery treatment that can be readily adopted in most radiotherapy centers with linear accelerators is presented. In our institution, a Leksell-type of neurosurgical frame, a computed tomography scanner, locally fabricated cones, and 6 MV X-ray beams are used to perform radiosurgery treatments. Collimated arcs with dose distributions that conform to the shape of the lesion in the transverse and the sagittal planes are used. It is argued that the uncertainties in the localization of the isocenter within a lesion and the specifications of the size of the target volume do not justify high precision mechanical devices formore » most radiosurgery treatments.« less

  13. SU-E-T-492: Implementing a Method for Brain Irradiation in Rats Utilizing a Commercially Available Radiosurgery Irradiator

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cates, J; Drzymala, R

    2014-06-01

    Purpose: The purpose of the study was to implement a method for accurate rat brain irradiation using the Gamma Knife Perfexion unit. The system needed to be repeatable, efficient, and dosimetrically and spatially accurate. Methods: A platform (“rat holder”) was made such that it is attachable to the Leskell Gamma Knife G Frame. The rat holder utilizes two ear bars contacting bony anatomy and a front tooth bar to secure the rat. The rat holder fits inside of the Leskell localizer box, which utilizes fiducial markers to register with the GammaPlan planning system. This method allows for accurate, repeatable setup.Amore » cylindrical phantom was made so that film can be placed axially in the phantom. We then acquired CT image sets of the rat holder and localizer box with both a rat and the phantom. Three treatment plans were created: a plan on the rat CT dataset, a phantom plan with the same prescription dose as the rat plan, and a phantom plan with the same delivery time as the rat plan. Results: Film analysis from the phantom showed that our setup is spatially accurate and repeatable. It is also dosimetrically accurate, with an difference between predicted and measured dose of 2.9%. Film analysis with prescription dose equal between rat and phantom plans showed a difference of 3.8%, showing that our phantom is a good representation of the rat for dosimetry purposes, allowing for +/- 3mm diameter variation. Film analysis with treatment time equal showed an error of 2.6%, which means we can deliver a prescription dose within 3% accuracy. Conclusion: Our method for irradiation of rat brain has been shown to be repeatable, efficient, and accurate, both dosimetrically and spatially. We can treat a large number of rats efficiently while delivering prescription doses within 3% at millimeter level accuracy.« less

  14. Knife wound to the posterior fossa in a child.

    PubMed

    Mohan, Avinash L; Slim, Michel; Benzil, Deborah L

    2005-03-01

    Knife wounds to the posterior fossa are a rare occurrence, especially in children. We report an 8-year-old girl who sustained a penetrating knife injury through the occipital bone into the posterior fossa. On presentation, the large knife blade was firmly embedded in her head. Radiographic evaluation was limited to plain X-rays because of the large size and sharpness of the embedded blade. Innovative positioning was used during intubation and then the patient was positioned semi-prone on the operating room table. The blade was surgically removed and the dura was closed. Atypical penetrating cranial injuries in children may require the treatment team to take a creative approach to the evaluation and repair of the lesion in order to maximize patient safety and minimize the risk of neurological injury.

  15. SU-F-T-593: Technical Treatment Accuracy in a Clinic of Fractionated Stereotactic Radiosurgery

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bisht, R; Kale, S; Natanasabapathi, G

    2016-06-15

    Purpose: The purpose of this study is to estimate technical treatment accuracy in fractionated stereotactic radiosurgery (fSRS) using extend system (ES) of Gamma Knife (GK). Methods: The fSRS with GK relies on a patient specific re-locatable immobilization system. The reference treatment position is estimated using a digital probe and a repositioning check tool (RCT). The “calibration values” of RCT apertures were compared with measured values on RCT-QA tool to evaluate the standard error (SE) associated with RCT measurements. A treatment plan with single “4 mm collimator shot” was created to deliver a radiation dose of 5 Gy at the predefinedmore » plane of a newly designed in-house head-neck phantom. The plan was investigated using radiochromic EBT3 films. The stereotactic CT imaging of a designed mini CT phantom and distortion study of MR imaging, were combined to calculate imaging SE. The focal precision check for GK machine tolerance was performed using a central diode test tool. Results: Twenty observations of RCT and digital probe, shown the SE of +/−0.0186mm and +/−0.0002mm respectively. A mean positional shift of 0.2752mm (σ=0.0696mm) was observed for twenty similar treatment settings of head-neck phantom. The difference between radiological and predefined exposure point was 0.4650mm and 0.4270mm; for two independent experiments. The imaging studies showed a combined SE of +/− 0.1055mm. Twenty frequent runs of a diode test tool showed the tolerance SE of +/−0.0096mm. If, the measurements are considered to be at 95% of confidence level, an expanded uncertainty was evaluated as +/− 0.2371mm with our system. The positional shift, when combined with an expanded uncertainty, a trivial variation of 0.07mm (max) was observed in comparing resultant radiological precision through film investigations. Conclusion: The study proposes an expression of “technical treatment accuracy” within “known uncertainties” is rational in the estimation

  16. Calvarial and skull base metastases: expanding the clinical utility of Gamma Knife surgery.

    PubMed

    Kotecha, Rupesh; Angelov, Lilyana; Barnett, Gene H; Reddy, Chandana A; Suh, John H; Murphy, Erin S; Neyman, Gennady; Chao, Samuel T

    2014-12-01

    Traditionally, the treatment of choice for patients with metastases to the calvaria or skull base has been conventional radiation therapy. Because patients with systemic malignancies are also at risk for intracranial metastases, the utility of Gamma Knife surgery (GKS) for these patients has been explored to reduce excess radiation exposure to the perilesional brain parenchyma. The purpose of this study was to report the efficacy of GKS for the treatment of calvarial metastases and skull base lesions. The authors performed a retrospective chart review of 21 patients with at least 1 calvarial or skull base metastatic lesion treated with GKS during 2001-2013. For 7 calvarial lesions, a novel technique, in which a bolus was placed over the treatment site, was used. For determination of local control or disease progression, radiation therapy data were examined and posttreatment MR images and oncology records were reviewed. Survival times from the date of procedure were estimated by using Kaplan-Meier analyses. The median patient age at treatment was 57 years (range 29-84 years). A total of 19 (90%) patients received treatment for single lesions, 1 patient received treatment for 3 lesions, and 1 patient received treatment for 4 lesions. The most common primary tumor was breast cancer (24% of patients). Per lesion, the median clinical and radiographic follow-up times were 10.3 months (range 0-71.9 months) and 7.1 months (range 0-61.3 months), respectively. Of the 26 lesions analyzed, 14 (54%) were located in calvarial bones and 12 (46%) were located in the skull base. The median lesion volume was 5.3 cm(3) (range 0.3-55.6 cm(3)), and the median prescription margin dose was 15 Gy (range 13-24 Gy). The median overall survival time for all patients was 35.9 months, and the 1-year local control rate was 88.9% (95% CI 74.4%-100%). Local control rates did not differ between lesions treated with the bolus technique and those treated with traditional methods or between calvarial

  17. Experimental Comparison of Knife-Edge and Multi-Parallel Slit Collimators for Prompt Gamma Imaging of Proton Pencil Beams.

    PubMed

    Smeets, Julien; Roellinghoff, Frauke; Janssens, Guillaume; Perali, Irene; Celani, Andrea; Fiorini, Carlo; Freud, Nicolas; Testa, Etienne; Prieels, Damien

    2016-01-01

    More and more camera concepts are being investigated to try and seize the opportunity of instantaneous range verification of proton therapy treatments offered by prompt gammas emitted along the proton tracks. Focusing on one-dimensional imaging with a passive collimator, the present study experimentally compared in combination with the first, clinically compatible, dedicated camera device the performances of instances of the two main options: a knife-edge slit (KES) and a multi-parallel slit (MPS) design. These two options were experimentally assessed in this specific context as they were previously demonstrated through analytical and numerical studies to allow similar performances in terms of Bragg peak retrieval precision and spatial resolution in a general context. Both collimators were prototyped according to the conclusions of Monte Carlo optimization studies under constraints of equal weight (40 mm tungsten alloy equivalent thickness) and of the specificities of the camera device under consideration (in particular 4 mm segmentation along beam axis and no time-of-flight discrimination, both of which less favorable to the MPS performance than to the KES one). Acquisitions of proton pencil beams of 100, 160, and 230 MeV in a PMMA target revealed that, in order to reach a given level of statistical precision on Bragg peak depth retrieval, the KES collimator requires only half the dose the present MPS collimator needs, making the KES collimator a preferred option for a compact camera device aimed at imaging only the Bragg peak position. On the other hand, the present MPS collimator proves more effective at retrieving the entrance of the beam in the target in the context of an extended camera device aimed at imaging the whole proton track within the patient.

  18. Predictive factors of tumor control and survival after radiosurgery for local failures of nasopharyngeal carcinoma.

    PubMed

    Chua, Daniel T T; Sham, Jonathan S T; Hung, Kwan-Ngai; Leung, Lucullus H T; Au, Gordon K H

    2006-12-01

    Stereotactic radiosurgery has been employed as a salvage treatment of local failures of nasopharyngeal carcinoma (NPC). To identify patients that would benefit from radiosurgery, we reviewed our data with emphasis on factors that predicted treatment outcome. A total of 48 patients with local failures of NPC were treated by stereotactic radiosurgery between March 1996 and February 2005. Radiosurgery was administered using a modified linear accelerator with single or multiple isocenters to deliver a median dose of 12.5 Gy to the target periphery. Median follow-up was 54 months. Five-year local failure-free probability after radiosurgery was 47.2% and 5-year overall survival rate was 46.9%. Neuroendocrine complications occurred in 27% of patients but there were no treatment-related deaths. Time interval from primary radiotherapy, retreatment T stage, prior local failures and tumor volume were significant predictive factors of local control and/or survival whereas age was of marginal significance in predicting survival. A radiosurgery prognostic scoring system was designed based on these predictive factors. Five-year local failure-free probabilities in patients with good, intermediate and poor prognostic scores were 100%, 42.5%, and 9.6%. The corresponding five-year overall survival rates were 100%, 51.1%, and 0%. Important factors that predicted tumor control and survival after radiosurgery were identified. Patients with good prognostic score should be treated by radiosurgery in view of the excellent results. Patients with intermediate prognostic score may also be treated by radiosurgery but those with poor prognostic score should receive other salvage treatments.

  19. SU-E-T-568: Improving Normal Brain Sparing with Increasing Number of Arc Beams for Volume Modulated Arc Beam Radiosurgery of Multiple Brain Metastases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hossain, S; Hildebrand, K; Ahmad, S

    Purpose: Intensity modulated arc beams have been newly reported for treating multiple brain metastases. The purpose of this study was to determine the variations in the normal brain doses with increasing number of arc beams for multiple brain metastases treatments via the TrueBeam Rapidarc system (Varian Oncology, Palo Alto, CA). Methods: A patient case with 12 metastatic brain lesions previously treated on the Leksell Gamma Knife Perfexion (GK) was used for the study. All lesions and organs at risk were contoured by a senior radiation oncologist and treatment plans for a subset of 3, 6, 9 and all 12 targetsmore » were developed for the TrueBeam Rapidarc system via 3 to 7 intensity modulated arc-beams with each target covered by at least 99% of the prescribed dose of 20 Gy. The peripheral normal brain isodose volumes as well as the total beam-on time were analyzed with increasing number of arc beams for these targets. Results: All intensisty modulated arc-beam plans produced efficient treatment delivery with the beam-on time averaging 0.6–1.5 min per lesion at an output of 1200 MU/min. With increasing number of arc beams, the peripheral normal brain isodose volumes such as the 12-Gy isodose line enclosed normal brain tissue volumes were on average decreased by 6%, 11%, 18%, and 28% for the 3-, 6-, 9-, 12-target treatment plans respectively. The lowest normal brain isodose volumes were consistently found for the 7-arc treatment plans for all the cases. Conclusion: With nearly identical beam-on times, the peripheral normal brain dose was notably decreased when the total number of intensity modulated arc beams was increased when treating multiple brain metastases. Dr Sahgal and Dr Ma are currently serving on the board of international society of stereotactic radiosurgery.« less

  20. Some observations on glass-knife making.

    PubMed

    Ward, R T

    1977-11-01

    The yield of usable knife edge per knife (for thin sectioning) was markedly increased when glass knives were made at an included angle of 55 degrees rather than the customary 45 degrees. A large number of measurements of edge check marks made with a routine light scattering method as well as observations made on a smaller number of test sections with the electron microscope indicated the superiority of 55 degrees knives. Knives were made with both taped pliers and an LKB Knifemaker. Knives were graded by methods easily applied in any biological electron microscope laboratory. Depending on the mode of fracture, the yield of knives having more than 33% of their edges free of check marks was 30 to 100 times greater at 55 degrees than 45 degrees.

  1. Knife inflicted penetrating injuries of the maxillofacial region: a descriptive, record-based study.

    PubMed

    Meer, M; Siddiqi, A; Morkel, J A; Janse van Rensburg, P; Zafar, S

    2010-01-01

    Penetrating knife injuries of the face are more common in South Africa than the rest of the world. These injuries can be life-threatening, especially where the major blood vessels of the face are involved. The approach to treatment should be multidisciplinary, beginning with the trauma unit to provide airway maintenance and haemodynamic stabilisation. An interventional radiologist may be consulted for angiography. The aim of the present study was to retrospectively analyse all cases of knife-inflicted penetrating injuries to the maxillofacial region with the knife in situ and subsequently develop a management protocol to be used by maxillofacial surgery registrars when presented with such cases. It was a retrospective, cross-sectional and record-based study, analysing all penetrating knife injuries reported at various hospitals for a period of 11 years. In this study, 24 cases of knife injuries were analysed. Twenty-one patients (87.5%) in this series were male and three (12.5%) were female. Of these 24 patients, 13 (54.2%) were coloured and 11 (45.8%) were black. There were no white or Indian patients. Post-surgical recovery of all patients was rapid and uneventful, and there were no fatalities. Patients with knife injuries to the face with no definite signs of vascular injury can thus be safely and accurately managed on the basis of physical examination and plain-film radiography. An angiogram is mandatory if the patient presents with excessive bleeding, an expanding haematoma or if the knife blade is in the region of any large vessels.

  2. Cost-effectiveness of focused ultrasound, radiosurgery, and DBS for essential tremor.

    PubMed

    Ravikumar, Vinod K; Parker, Jonathon J; Hornbeck, Traci S; Santini, Veronica E; Pauly, Kim Butts; Wintermark, Max; Ghanouni, Pejman; Stein, Sherman C; Halpern, Casey H

    2017-08-01

    Essential tremor remains a very common yet medically refractory condition. A recent phase 3 study demonstrated that magnetic resonance-guided focused ultrasound thalamotomy significantly improved upper limb tremor. The objectives of this study were to assess this novel therapy's cost-effectiveness compared with existing procedural options. Literature searches of magnetic resonance-guided focused ultrasound thalamotomy, DBS, and stereotactic radiosurgery for essential tremor were performed. Pre- and postoperative tremor-related disability scores were collected from 32 studies involving 83 magnetic resonance-guided focused ultrasound thalamotomies, 615 DBSs, and 260 stereotactic radiosurgery cases. Utility, defined as quality of life and derived from percent change in functional disability, was calculated; Medicare reimbursement was employed as a proxy for societal cost. Medicare reimbursement rates are not established for magnetic resonance-guided focused ultrasound thalamotomy for essential tremor; therefore, reimbursements were estimated to be approximately equivalent to stereotactic radiosurgery to assess a cost threshold. A decision analysis model was constructed to examine the most cost-effective option for essential tremor, implementing meta-analytic techniques. Magnetic resonance-guided focused ultrasound thalamotomy resulted in significantly higher utility scores compared with DBS (P < 0.001) or stereotactic radiosurgery (P < 0.001). Projected costs of magnetic resonance-guided focused ultrasound thalamotomy were significantly less than DBS (P < 0.001), but not significantly different from radiosurgery. Magnetic resonance-guided focused ultrasound thalamotomy is cost-effective for tremor compared with DBS and stereotactic radiosurgery and more effective than both. Even if longer follow-up finds changes in effectiveness or costs, focused ultrasound thalamotomy will likely remain competitive with both alternatives. © 2017 International Parkinson and Movement

  3. Impact of CyberKnife Radiosurgery on Overall Survival and Various Parameters of Patients with 1-3 versus ≥ 4 Brain Metastases.

    PubMed

    Murovic, Judith; Ding, Victoria; Han, Summer S; Adler, John R; Chang, Steven D

    2017-10-24

    Introduction This study's objective is to compare the overall survivals (OSs) and various parameters of patients with 1-3 versus ≥ 4 brain metastases post-CyberKnife radiosurgery (CKRS) (Accuray, Sunnyvale, California) alone. Methods Charts of 150 patients, from 2009-2014, treated with only CKRS for brain metastases were reviewed retrospectively for overall survival (OS) and patient, tumor, and imaging characteristics. Parameters included demographics, Eastern Cooperative Oncology Group (ECOG) performance scores, number and control of extracranial disease (ECD) sites, cause of death (COD), histology, tumor volume (TV), and post-CKRS whole brain radiotherapy (WBRT). The imaging characteristics assessed were time of complete response (CR), partial response (PR), stable imaging or local failure (LF), and distal brain failure (DBF). Patients and their data were divided into those with 1-3 (group 1) versus ≥ 4 brain metastases (group 2). For each CR and LF patient, absolute neutrophil count (ANC), absolute lymphocyte count (ALC)), and ANC/ALC ratio (NLR) were obtained, when available, at the time of CKRS. Results Both group 1 and group 2 had a median OS of 13 months. The patient median age for the 115 group 1 patients versus the 35 group 2 patients was 62 versus 56 years. Group 1 had slightly more males and group 2, females. The predominant ECOG score for each group was 1 and the number of ECD sites was one and two, respectively. Uncontrolled ECD occurred in the majority of both group 1 and group 2 patients. The main COD was ECD in both groups. The prevalent tumor histology for groups 1 and 2 was non-small cell lung carcinoma. Median TVs were 1.08 cc versus 1.42 cc for groups 1 and 2, respectively. The majority of patients in both groups did not undergo post-CKRS WBRT. Imaging outcomes were LC (CR, PR, or stable imaging) in 93 (80.9%) and 26 (74.3%) group 1 and 2 patients, of whom 32 (27.8%) and six (17.1%) had CR; 38 (33.0%) and 18 (51.4%), PR and 23

  4. Stereotactic Radiosurgery in the Management of Limited (1-4) Brain Metasteses: Systematic Review and International Stereotactic Radiosurgery Society Practice Guideline.

    PubMed

    Chao, Samuel T; De Salles, Antonio; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Martinez, Roberto; Paddick, Ian; Régis, Jean; Ryu, Samuel; Slotman, Ben J; Sahgal, Arjun

    2017-11-03

    Guidelines regarding stereotactic radiosurgery (SRS) for brain metastases are missing recently published evidence. To conduct a systematic review and provide an objective summary of publications regarding SRS in managing patients with 1 to 4 brain metastases. Using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using PubMed and Medline up to November 2016. A separate search was conducted for SRS for larger brain metastases. Twenty-seven prospective studies, critical reviews, meta-analyses, and published consensus guidelines were reviewed. Four key points came from these studies. First, there is no detriment to survival by withholding whole brain radiation (WBRT) in the upfront management of brain metastases with SRS. Second, while SRS on its own provides a high rate of local control (LC), WBRT may provide further increase in LC. Next, WBRT does provide distant brain control with less need for salvage therapy. Finally, the addition of WBRT does affect neurocognitive function and quality of life more than SRS alone. For larger brain metastases, surgical resection should be considered, especially when factoring lower LC with single-session radiosurgery. There is emerging data showing good LC and/or decreased toxicity with multisession radiosurgery. A number of well-conducted prospective and meta-analyses studies demonstrate good LC, without compromising survival, using SRS alone for patients with a limited number of brain metastases. Some also demonstrated less impact on neurocognitive function with SRS alone. Practice guidelines were developed using these data with International Stereotactic Radiosurgery Society consensus. Copyright © 2017 by the Congress of Neurological Surgeons

  5. Outcome of peroral endoscopic myotomy in achalasia cardia: Experience with a new triangular knife.

    PubMed

    Nabi, Zaheer; Ramchandani, Mohan; Chavan, Radhika; Kalapala, Rakesh; Darisetty, Santosh; Reddy, D Nageshwar

    2018-01-01

    Peroral endoscopic myotomy (POEM) is a technically demanding procedure. Recently, a new triangular knife with integrated water jet function (TTJ) has been introduced. The present study was aimed to analyze and compare the operating time, efficacy, and adverse events (AEs) between the conventional (TT knife) and new knife (TTJ). All patients with achalasia cardia (AC) who underwent POEM between August 2015 and November 2016 were analyzed retrospectively. Operating time (OT), technical success, and AEs were assessed and compared between TT and TTJ knife. A total of 193 patients with AC underwent POEM during the specified period. Both groups had equivalent number of different subtypes of AC (I, II, and III). There was no difference in technical success between the two groups (TT, 99% vs TT, 98.9%). OT was significantly less in the TTJ group as compared to TT group (53.8 ± 15.2 vs 66.26 ± 19.2; P = 0.0001). On subanalysis, OT taken for submucosal tunneling was significantly less with TTJ knife (34.6 ± 10.1 vs 45.83 ± 14.80), whereas OT was similar for myotomy and clipping in both the groups. Significantly fewer use of coagulation forceps and exchanges of accessories were required in TTJ knife group (2.92 ± 1.77 vs 10.5 ± 3.58; P = 0.0001). There were no major AEs. Minor AEs were noted in 21.5% and 31% of patients in TTJ and TT knife groups, respectively. New triangular knife reduces procedure time and technical difficulty with POEM. POEM is an efficacious treatment for achalasia and can be safely executed in an endoscopy unit.

  6. Prognostic Factors for Survival in Patients Treated With Stereotactic Radiosurgery for Recurrent Brain Metastases After Prior Whole Brain Radiotherapy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Caballero, Jorge A.; Sneed, Penny K., E-mail: psneed@radonc.ucsf.edu; Lamborn, Kathleen R.

    2012-05-01

    Purpose: To evaluate prognostic factors for survival after stereotactic radiosurgery (SRS) for new, progressive, or recurrent brain metastases (BM) after prior whole brain radiotherapy (WBRT). Methods and Materials: Patients treated between 1991 and 2007 with Gamma Knife SRS for BM after prior WBRT were retrospectively reviewed. Potential prognostic factors were analyzed overall and by primary site using univariate and stepwise multivariate analyses and recursive partitioning analysis, including age, Karnofsky performance status (KPS), primary tumor control, extracranial metastases, number of BM treated, total SRS target volume, and interval from WBRT to SRS. Results: A total of 310 patients were analyzed, includingmore » 90 breast, 113 non-small-cell lung, 31 small-cell lung, 42 melanoma, and 34 miscellaneous patients. The median age was 56, KPS 80, number of BM treated 3, and interval from WBRT to SRS 8.1 months; 76% had controlled primary tumor and 60% had extracranial metastases. The median survival was 8.4 months overall and 12.0 vs. 7.9 months for single vs. multiple BM treated (p = 0.001). There was no relationship between number of BM and survival after excluding single-BM patients. On multivariate analysis, favorable prognostic factors included age <50, smaller total target volume, and longer interval from WBRT to SRS in breast cancer patients; smaller number of BM, KPS >60, and controlled primary in non-small-cell lung cancer patients; and smaller total target volume in melanoma patients. Conclusions: Among patients treated with salvage SRS for BM after prior WBRT, prognostic factors appeared to vary by primary site. Although survival time was significantly longer for patients with a single BM, the median survival time of 7.9 months for patients with multiple BM seems sufficiently long for salvage SRS to appear to be worthwhile, and no evidence was found to support the use of a cutoff for number of BM appropriate for salvage SRS.« less

  7. Observation of Phase Objects by Using an X-ray Microscope with a Foucault Knife-Edge

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Watanabe, N.; Sasaya, T.; Imai, Y.

    2011-09-09

    An x-ray microscope with a zone plate was assembled at the synchrotron radiation source of BL3C, Photon Factory. A Foucault knife-edge was set at the back focal plate of the objective zone plate and phase retrieval was tested by scanning the knife-edge. A preliminary result shows that scanning the knife-edge during exposure was effective for phase retrieval. Phase-contrast tomography was investigated using differential projection images calculated from two Schlieren images with the oppositely oriented knife-edges. Fairly good reconstruction images of polystyrene beads and spores could be obtained.

  8. The treatment of recurrent brain metastases with stereotactic radiosurgery.

    PubMed

    Loeffler, J S; Kooy, H M; Wen, P Y; Fine, H A; Cheng, C W; Mannarino, E G; Tsai, J S; Alexander, E

    1990-04-01

    Between May 1986 and August 1989, we treated 18 patients with 21 recurrent or persistent brain metastases with stereotactic radiosurgery using a modified linear accelerator. To be eligible for radiosurgery, patients had to have a performance status of greater than or equal to 70% and have no evidence of (or stable) systemic disease. All but one patient had received prior radiotherapy, and were treated with stereotactic radiosurgery at the time of recurrence. Polar lesions were treated only if the patient had undergone and failed previous complete surgical resection (10 patients). Single doses of radiation (900 to 2,500 cGy) were delivered to limited volumes (less than 27 cm3) using a modified 6MV linear accelerator. The most common histology of the metastatic lesion was carcinoma of the lung (seven patients), followed by carcinoma of the breast (four patients), and melanoma (four patients). With median follow-up of 9 months (range, 1 to 39), all tumors have been controlled in the radiosurgery field. Two patients failed in the immediate margin of the treated volume and were subsequently treated with surgery and implantation of 125I to control the disease. Radiographic response was dramatic and rapid in the patients with adenocarcinoma, while slight reduction and stabilization occurred in those patients with melanoma, renal cell carcinoma, and sarcoma. The majority of patients improved neurologically following treatment, and were able to be withdrawn from corticosteroid therapy. Complications were limited and transient in nature and no cases of symptomatic radiation necrosis occurred in any patient despite previous exposure to radiotherapy. Stereotactic radiosurgery is an effective and relatively safe treatment for recurrent solitary metastases and is an appealing technique for the initial management of deep-seated lesions as a boost to whole brain radiotherapy.

  9. Characteristics and Treatments of Large Cystic Brain Metastasis: Radiosurgery and Stereotactic Aspiration

    PubMed Central

    Kim, Moinay; Cheok, Stephanie; Chung, Lawrance K.; Ung, Nolan; Thill, Kimberly; Voth, Brittany; Kwon, Do Hoon; Kim, Jeong Hoon; Kim, Chang Jin; Tenn, Stephen; Lee, Percy

    2015-01-01

    Brain metastasis represents one of the most common causes of intracranial tumors in adults, and the incidence of brain metastasis continues to rise due to the increasing survival of cancer patients. Yet, the development of cystic brain metastasis remains a relatively rare occurrence. In this review, we describe the characteristics of cystic brain metastasis and evaluate the combined use of stereotactic aspiration and radiosurgery in treating large cystic brain metastasis. The results of several studies show that stereotactic radiosurgery produces comparable local tumor control and survival rates as other surgery protocols. When the size of the tumor interferes with radiosurgery, stereotactic aspiration of the metastasis should be considered to reduce the target volume as well as decreasing the chance of radiation induced necrosis and providing symptomatic relief from mass effect. The combined use of stereotactic aspiration and radiosurgery has strong implications in improving patient outcomes. PMID:25977901

  10. Thermal welding vs. cold knife tonsillectomy: a comparison of voice and speech.

    PubMed

    Celebi, Saban; Yelken, Kursat; Celik, Oner; Taskin, Umit; Topak, Murat

    2011-01-01

    To compare acoustic, aerodynamic and perceptual voice and speech parameters in thermal welding system tonsillectomy and cold knife tonsillectomy patients in order to determine the impact of operation technique on voice and speech. Thirty tonsillectomy patients (22 children, 8 adults) participated in this study. The preferred technique was cold knife tonsillectomy in 15 patients and thermal welding system tonsillectomy in the remaining 15 patients. One week before and 1 month after surgery the following parameters were estimated: average of fundamental frequency, Jitter, Shimmer, harmonic to noise ratio, formant frequency analyses of sustained vowels. Perceptual speech analysis and aerodynamic measurements (maximum phonation time and s/z ratio) were also conducted. There was no significant difference in any of the parameters between cold knife tonsillectomy and thermal welding system tonsillectomy groups (p>0.05). When the groups were contrasted among themselves with regards to preoperative and postoperative rates, fundamental frequency was found to be significantly decreased after tonsillectomy in both of the groups (p<0.001). First formant for the vowel /a/ in the cold knife tonsillectomy group and for the vowel /i/ in the thermal welding system tonsillectomy group, second formant for the vowel /u/ in the thermal welding system tonsillectomy group and third formant for the vowel /u/ in the cold knife tonsillectomy group were found to be significantly decreased (p<0.05). The surgical technique, whether it is cold knife or thermal welding system, does not appear to affect voice and speech in tonsillectomy patients. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  11. Knife-edge seal for vacuum bagging

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1980-01-01

    Cam actuated clamps pinch bagging material between long knife edge (mounted to clamps) and high temperature rubber cushion bonded to baseplate. No adhesive, tape, or sealing groove is needed to seal edge of bagging sheet against base plate.

  12. Results of stereotactic radiosurgery for patients with imaging defined cavernous sinus meningiomas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pollock, Bruce E.; Stafford, Scott L.

    2005-08-01

    Introduction: The purpose of this study was to evaluate the efficacy and safety of stereotactic radiosurgery as primary management for patients with imaging defined cavernous sinus meningiomas. Methods: Between 1992 and 2001, 49 patients had radiosurgery for dural-based masses of the cavernous sinus presumed to be meningiomas. The mean patient age was 55.5 years. The mean tumor volume was 10.2 mL; the mean tumor margin dose was 15.9 Gy. The mean follow-up was 58 months (range, 16-144 months). Results: No tumor enlarged after radiosurgery. Twelve of 38 patients (26%) with preexisting diplopia or facial numbness/pain had improvement in cranial nervemore » function. Five patients (10%) had new (n = 3) or worsened (n = 2) trigeminal dysfunction; 2 of these patients (4%) underwent surgery at 20 and 25 months after radiosurgery despite no evidence of tumor progression. Neither patient improved after partial tumor resection. One patient (2%) developed an oculomotor nerve injury. One patient (2%) had an ischemic stroke related to occlusion of the cavernous segment of the internal carotid artery. Event-free survival was 98%, 85%, and 80% at 1, 3, and 7 years after radiosurgery, respectively. Univariate analysis of patient and dosimetric factors found no analyzed factor correlated with postradiosurgical morbidity. Conclusions: Radiosurgery was an effective primary management strategy for patients with an imaging defined cavernous sinus meningioma. Except in situations of symptomatic mass effect, unusual clinical presentation, or atypical imaging features, surgery to confirm the histologic diagnosis is unlikely to provide clinical benefit.« less

  13. Management of Liver Cancer Argon-helium Knife Therapy with Functional Computer Tomography Perfusion Imaging.

    PubMed

    Wang, Hongbo; Shu, Shengjie; Li, Jinping; Jiang, Huijie

    2016-02-01

    The objective of this study was to observe the change in blood perfusion of liver cancer following argon-helium knife treatment with functional computer tomography perfusion imaging. Twenty-seven patients with primary liver cancer treated with argon-helium knife and were included in this study. Plain computer tomography (CT) and computer tomography perfusion (CTP) imaging were conducted in all patients before and after treatment. Perfusion parameters including blood flows, blood volume, hepatic artery perfusion fraction, hepatic artery perfusion, and hepatic portal venous perfusion were used for evaluating therapeutic effect. All parameters in liver cancer were significantly decreased after argon-helium knife treatment (p < 0.05 to all). Significant decrease in hepatic artery perfusion was also observed in pericancerous liver tissue, but other parameters kept constant. CT perfusion imaging is able to detect decrease in blood perfusion of liver cancer post-argon-helium knife therapy. Therefore, CTP imaging would play an important role for liver cancer management followed argon-helium knife therapy. © The Author(s) 2014.

  14. A sharp knife for high temperatures

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Iceland, W. F.

    1978-01-01

    Electrically heated nickel-chrome-steel alloy knife may be used to cut heat resistant plastic felt and similar materials with relative ease. Blade made of commercially available alloy RA 330 retains edge at temperatures as high as 927 C.

  15. Outcome of peroral endoscopic myotomy in achalasia cardia: Experience with a new triangular knife

    PubMed Central

    Nabi, Zaheer; Ramchandani, Mohan; Chavan, Radhika; Kalapala, Rakesh; Darisetty, Santosh; Reddy, D. Nageshwar

    2018-01-01

    Background and Aim: Peroral endoscopic myotomy (POEM) is a technically demanding procedure. Recently, a new triangular knife with integrated water jet function (TTJ) has been introduced. The present study was aimed to analyze and compare the operating time, efficacy, and adverse events (AEs) between the conventional (TT knife) and new knife (TTJ). Patients and Methods: All patients with achalasia cardia (AC) who underwent POEM between August 2015 and November 2016 were analyzed retrospectively. Operating time (OT), technical success, and AEs were assessed and compared between TT and TTJ knife. Results: A total of 193 patients with AC underwent POEM during the specified period. Both groups had equivalent number of different subtypes of AC (I, II, and III). There was no difference in technical success between the two groups (TT, 99% vs TT, 98.9%). OT was significantly less in the TTJ group as compared to TT group (53.8 ± 15.2 vs 66.26 ± 19.2; P = 0.0001). On subanalysis, OT taken for submucosal tunneling was significantly less with TTJ knife (34.6 ± 10.1 vs 45.83 ± 14.80), whereas OT was similar for myotomy and clipping in both the groups. Significantly fewer use of coagulation forceps and exchanges of accessories were required in TTJ knife group (2.92 ± 1.77 vs 10.5 ± 3.58; P = 0.0001). There were no major AEs. Minor AEs were noted in 21.5% and 31% of patients in TTJ and TT knife groups, respectively. Conclusion: New triangular knife reduces procedure time and technical difficulty with POEM. POEM is an efficacious treatment for achalasia and can be safely executed in an endoscopy unit. PMID:29451180

  16. Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma.

    PubMed

    Shah, Jennifer L; Li, Gordon; Shaffer, Jenny L; Azoulay, Melissa I; Gibbs, Iris C; Nagpal, Seema; Soltys, Scott G

    2018-01-01

    Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma. Copyright © 2017 by the Congress of Neurological Surgeons.

  17. A Simple and Efficient Methodology To Improve Geometric Accuracy in Gamma Knife Radiation Surgery: Implementation in Multiple Brain Metastases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Karaiskos, Pantelis, E-mail: pkaraisk@med.uoa.gr; Gamma Knife Department, Hygeia Hospital, Athens; Moutsatsos, Argyris

    Purpose: To propose, verify, and implement a simple and efficient methodology for the improvement of total geometric accuracy in multiple brain metastases gamma knife (GK) radiation surgery. Methods and Materials: The proposed methodology exploits the directional dependence of magnetic resonance imaging (MRI)-related spatial distortions stemming from background field inhomogeneities, also known as sequence-dependent distortions, with respect to the read-gradient polarity during MRI acquisition. First, an extra MRI pulse sequence is acquired with the same imaging parameters as those used for routine patient imaging, aside from a reversal in the read-gradient polarity. Then, “average” image data are compounded from data acquiredmore » from the 2 MRI sequences and are used for treatment planning purposes. The method was applied and verified in a polymer gel phantom irradiated with multiple shots in an extended region of the GK stereotactic space. Its clinical impact in dose delivery accuracy was assessed in 15 patients with a total of 96 relatively small (<2 cm) metastases treated with GK radiation surgery. Results: Phantom study results showed that use of average MR images eliminates the effect of sequence-dependent distortions, leading to a total spatial uncertainty of less than 0.3 mm, attributed mainly to gradient nonlinearities. In brain metastases patients, non-eliminated sequence-dependent distortions lead to target localization uncertainties of up to 1.3 mm (mean: 0.51 ± 0.37 mm) with respect to the corresponding target locations in the “average” MRI series. Due to these uncertainties, a considerable underdosage (5%-32% of the prescription dose) was found in 33% of the studied targets. Conclusions: The proposed methodology is simple and straightforward in its implementation. Regarding multiple brain metastases applications, the suggested approach may substantially improve total GK dose delivery accuracy in smaller, outlying targets.« less

  18. Monte Carlo and experimental determination of correction factors for gamma knife perfexion small field dosimetry measurements

    NASA Astrophysics Data System (ADS)

    Zoros, E.; Moutsatsos, A.; Pappas, E. P.; Georgiou, E.; Kollias, G.; Karaiskos, P.; Pantelis, E.

    2017-09-01

    Detector-, field size- and machine-specific correction factors are required for precise dosimetry measurements in small and non-standard photon fields. In this work, Monte Carlo (MC) simulation techniques were used to calculate the k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} and k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors for a series of ionization chambers, a synthetic microDiamond and diode dosimeters, used for reference and/or output factor (OF) measurements in the Gamma Knife Perfexion photon fields. Calculations were performed for the solid water (SW) and ABS plastic phantoms, as well as for a water phantom of the same geometry. MC calculations for the k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors in SW were compared against corresponding experimental results for a subset of ionization chambers and diode detectors. Reference experimental OF data were obtained through the weighted average of corresponding measurements using TLDs, EBT-2 films and alanine pellets. k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} values close to unity (within 1%) were calculated for most of ionization chambers in water. Greater corrections of up to 6.0% were observed for chambers with relatively large air-cavity dimensions and steel central electrode. A phantom correction of 1.006 and 1.024 (breaking down to 1.014 from the ABS sphere and 1.010 from the accompanying ABS phantom adapter) were calculated for the SW and ABS phantoms, respectively, adding up to k{{Qmsr},{{Q}0}}{{fmsr},{{f}ref}} corrections in water. Both measurements and MC calculations for the diode and microDiamond detectors resulted in lower than unit k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} correction factors, due to their denser sensitive volume and encapsulation materials. In comparison, higher than unit k{{Qclin},{{Q}msr}}{{fclin},{{f}msr}} results for the ionization chambers suggested field size depended dose underestimations (being significant for the 4 mm field), with magnitude depending on the combination of

  19. Interest of submucosal dissection knife for endoscopic treatment of Zenker's diverticulum.

    PubMed

    Laquière, A; Grandval, P; Arpurt, J P; Boulant, J; Belon, S; Aboukheir, S; Laugier, R; Penaranda, G; Curel, L; Boustière, C

    2015-09-01

    Dual-Knife(®) (Olympus) and Hydride-Knife(®) are new needle knives frequently used for submucosal dissection because of their safety and precision. In this study we aimed to evaluate the efficacy and safety of such devices in the diverticulopexy by flexible endoscopy. From February 2009 to March 2013, 42 patients (25 men), mean age 74.5, with symptomatic Zenker's diverticulum, were included in a non-randomized prospective multicenter study. The symptoms described by all patients include dysphagia, regurgitation and/or swallowing disorders. The diverticulopexy was performed with the Dual-Knife(®) or Hydrid-Knife(®), after septum exposure with the diverticuloscope, and terminated with distal tip clips positioning. All complications were noted. Patients' symptoms were regularly assessed during follow-up visits or telephone interviews. The first endoscopy treatment was successful for all patients. Thirty-seven patients (88%) had symptoms improvement after the first treatment. The recurrence rate was 14% (6 patients); a second endoscopic treatment was required 12 months on average after the first treatment, with 100% efficiency. Mid-term (16 months) efficiency was 91.67% after 1 to 3 endoscopic treatments. A total of 55 procedures were performed without perforation or significant bleeding and 3 patients underwent surgery. In multivariate analysis, the diverticulum size and the type of dissection knife were not risks factors for recurrence. Endoscopic diverticuloscope-assisted diverticulotomy with submucosal dissection knives is a safe and effective alternative treatment for patients with a symptomatic Zenker's diverticulum measuring between 2 and 10 cm.

  20. Influence on grip of knife handle surface characteristics and wearing protective gloves.

    PubMed

    Claudon, Laurent

    2006-11-01

    Ten subjects were asked to apply maximum torques on knife handles with either their bare hand or their hand wearing a Kevlar fibre protective glove. Four knife handles (2 roughnesses, 2 hardnesses) were tested. Surface electromyograms of 6 upper limb and shoulder muscles were recorded and subject opinions on both knife handle hardness and friction in the hand were also assessed. The results revealed the significant influence of wearing gloves (p<0.0001), knife type (p<0.0005) and handle hardness (p<0.005) on the applied torque. Wearing Kevlar fibre gloves greatly increased the torque independently of the other two parameters. Under the bare hand condition, a 90 degrees ShA slightly rough handle provided the greatest torque. Subject opinion agreed with the observed effects on recorded torque values except for the hardness factor, for which a preference for the 70 degrees ShA value over the 90 degrees ShA value emerged.