Sample records for gamma knife surgery

  1. 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.

  2. 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.

  3. 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

  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. 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.

  6. 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

  7. 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.

  8. 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 ...

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  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. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. [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.

  19. 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

  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. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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).

  13. 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

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. [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.

  6. 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

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. "Knife to skin" time is a poor marker of operating room utilization and efficiency in cardiac surgery.

    PubMed

    Luthra, Suvitesh; Ramady, Omar; Monge, Mary; Fitzsimons, Michael G; Kaleta, Terry R; Sundt, Thoralf M

    2015-06-01

    Markers of operation room (OR) efficiency in cardiac surgery are focused on "knife to skin" and "start time tardiness." These do not evaluate the middle and later parts of the cardiac surgical pathway. The purpose of this analysis was to evaluate knife to skin time as an efficiency marker in cardiac surgery. We looked at knife to skin time, procedure time, and transfer times in the cardiac operational pathway for their correlation with predefined indices of operational efficiency (Index of Operation Efficiency - InOE, Surgical Index of Operational Efficiency - sInOE). A regression analysis was performed to test the goodness of fit of the regression curves estimated for InOE relative to the times on the operational pathway. The mean knife to skin time was 90.6 ± 13 minutes (23% of total OR time). The mean procedure time was 282 ± 123 minutes (71% of total OR time). Utilization efficiencies were highest for aortic valve replacement and coronary artery bypass grafting and least for complex aortic procedures. There were no significant procedure-specific or team-specific differences for standard procedures. Procedure times correlated the strongest with InOE (r = -0.98, p < 0.01). Compared to procedure times, knife to skin is not as strong an indicator of efficiency. A statistically significant linear dependence on InOE was observed with "procedure times" only. Procedure times are a better marker of OR efficiency than knife to skin in cardiac cases. Strategies to increase OR utilization and efficiency should address procedure times in addition to knife to skin times. © 2015 Wiley Periodicals, Inc.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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

  4. 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

  5. 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.

  6. Are “knife and fork” good enough for day case surgery of resistant tennis elbow?

    PubMed Central

    Govindaswamy, Raja; Elbouni, Tariq; Chambler, Andrew F. W.

    2008-01-01

    This observational retrospective study was performed on 22 consecutive patients treated surgically in a day surgery unit for resistant tennis elbow to ascertain the effectiveness of the “knife and fork” procedure. All patients had an unfavourable response to nonsurgical treatment lasting at least six months. A simple and inexpensive “knife and fork” technique yielded excellent results in 90.5% of patients and a high percentage (95.2%) of satisfied patients at an average follow-up of two years. There were no fair or poor results and no complications. We conclude that the “knife and fork” technique is a simple and dependable day case procedure. In the present National Health Service (NHS) era of tariff and “payment by results”, this approach is more cost effective than an arthroscopic alternative. PMID:19096844

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Predictive Nomogram for the Durability of Pain Relief From Gamma Knife Radiation Surgery in the Treatment of Trigeminal Neuralgia

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

    Lucas, John T., E-mail: johnthomas75@gmail.com; Nida, Adrian M.; Isom, Scott

    Purpose: To determine factors associated with the durability of stereotactic radiation surgery (SRS) for treatment of trigeminal neuralgia (TN). Methods and Materials: Between 1999 and 2008, 446 of 777 patients with TN underwent SRS and had evaluable follow-up in our electronic medical records and phone interview records. The median follow-up was 21.2 months. The Barrow Neurologic Institute (BNI) pain scale was used to determine pre- and post-SRS pain. Dose-volume anatomical measurements, Burchiel pain subtype, pain quality, prior procedures, and medication usage were included in this retrospective cohort to identify factors impacting the time to BNI 4-5 pain relapse by using Cox proportionalmore » hazard regression. An internet-based nomogram was constructed based on predictive factors of durable relief pre- and posttreatment at 6-month intervals. Results: Rates of freedom from BNI 4-5 failure at 1, 3, and 5 years were 84.5%, 70.4%, and 46.9%, respectively. Pain relief was BNI 1-3 at 1, 3, and 5 years in 86.1%, 74.3%, and 51.3% of type 1 patients; 79.3%, 46.2%, and 29.3% of type 2 patients; and 62.7%, 50.2%, and 25% of atypical facial pain patients. BNI type 1 pain score was achieved at 1, 3, and 5 years in 62.9%, 43.5%, and 22.0% of patients with type 1 pain and in 47.5%, 25.2%, and 9.2% of type 2 patients, respectively. Only 13% of patients with atypical facial pain achieved BNI 1 response; 42% of patients developed post-Gamma Knife radiation surgery (GKRS) trigeminal dysfunction. Multivariate analysis revealed that post-SRS numbness (hazard ratio [HR], 0.47; P<.0001), type 1 (vs type 2) TN (HR, 0.6; P=.02), and improved post-SRS BNI score at 6 months (HR, 0.009; P<.0001) were predictive of a durable pain response. Conclusions: The durability of SRS for TN depends on the presenting Burchiel pain type, the post-SRS BNI score, and the presence of post-SRS facial numbness. The durability of pain relief can be estimated pre- and posttreatment by using

  20. 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.

  1. 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.

  2. Gamma knife surgery for refractory postherpetic trigeminal neuralgia: targeting in one session both the retrogasserian trigeminal nerve and the centromedian nucleus of the thalamus.

    PubMed

    Keep, Marcus F; DeMare, Paul A; Ashby, Lynn S

    2005-01-01

    The authors tested the hypothesis that two targets are needed to treat postherpetic trigeminal neuralgia (TN): one in the trigeminal nerve for the direct sharp pain and one in the thalamus for the diffuse burning pain. Three patients with refractory postherpetic TN were treated with gamma knife surgery (GKS) through a novel two-target approach. In a single treatment session, both the trigeminal nerve and centromedian nucleus were targeted. First, the trigeminal nerve, ipsilateral to the facial pain, was treated with 60 to 80 Gy. Second, the centromedian nucleus was localized using standard coordinates and by comparing magnetic resonance images with a stereotactic atlas. A single dose of 120 to 140 Gy was delivered to the target point with a single 4-mm isocenter. Patients were followed clinically and with neuroimaging studies. Pain relief was scored as excellent (75-100%), good (50-75%), poor (25-50%); or none (0-25%). Follow up ranged from 6 to 53 months. There were no GKS-related complications. Two patients died of unrelated medical illnesses but had good or excellent pain relief until death. One patient continues to survive with 44 months follow up and no decrease in pain intensity, but with a decreased area of pain. Combined GKS of the centromedian nucleus and trigeminal nerve in a single treatment session is feasible and safe, and the effect was promising. A larger study is required to confirm and expand these results.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  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. 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

  8. Semiquantitative Analysis Using Thallium-201 SPECT for Differential Diagnosis Between Tumor Recurrence and Radiation Necrosis After Gamma Knife Surgery for Malignant Brain Tumors

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

    Matsunaga, Shigeo, E-mail: shigeo-m@mui.biglobe.ne.jp; Shuto, Takashi; Takase, Hajime

    Purpose: Semiquantitative analysis of thallium-201 chloride single photon emission computed tomography ({sup 201}Tl SPECT) was evaluated for the discrimination between recurrent brain tumor and delayed radiation necrosis after gamma knife surgery (GKS) for metastatic brain tumors and high-grade gliomas. Methods and Materials: The medical records were reviewed of 75 patients, including 48 patients with metastatic brain tumor and 27 patients with high-grade glioma who underwent GKS in our institution, and had suspected tumor recurrence or radiation necrosis on follow-up neuroimaging and deteriorating clinical status after GKS. Analysis of {sup 201}Tl SPECT data used the early ratio (ER) and the delayedmore » ratio (DR) calculated as tumor/normal average counts on the early and delayed images, and the retention index (RI) as the ratio of DR to ER. Results: A total of 107 tumors were analyzed with {sup 201}Tl SPECT. Nineteen lesions were removed surgically and histological diagnoses established, and the other lesions were evaluated with follow-up clinical and neuroimaging examinations after GKS. The final diagnosis was considered to be recurrent tumor in 65 lesions and radiation necrosis in 42 lesions. Semiquantitative analysis demonstrated significant differences in DR (P=.002) and RI (P<.0001), but not in ER (P=.372), between the tumor recurrence and radiation necrosis groups, and no significant differences between metastatic brain tumors and high-grade gliomas in all indices (P=.926 for ER, P=.263 for DR, and P=.826 for RI). Receiver operating characteristics analysis indicated that RI was the most informative index with the optimum threshold of 0.775, which provided 82.8% sensitivity, 83.7% specificity, and 82.8% accuracy. Conclusions: Semiquantitative analysis of {sup 201}Tl SPECT provides useful information for the differentiation between tumor recurrence and radiation necrosis in metastatic brain tumors and high-grade gliomas after GKS, and the RI may be the

  9. 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

    Purpose: Aim of the study is to evaluate mechanical and radiological accuracy of multi-fraction regimen and validate Gamma knife based fractionation using newly developed patient simulating multipurpose phantom. Methods: A patient simulating phantom was designed to verify fractionated treatments with extend system (ES) of Gamma Knife however it could be used to validate other radiotherapy procedures as well. The phantom has options to insert various density material plugs and mini CT/MR distortion phantoms to analyze the quality of stereotactic imaging. An additional thorax part designed to predict surface doses at various organ sites. The phantom was positioned using vacuum headmore » cushion and patient control unit for imaging and treatment. The repositioning check tool (RCT) was used to predict phantom positioning under ES assembly. The phantom with special inserts for film in axial, coronal and sagittal plane were scanned with X-Ray CT and the acquired images were transferred to treatment planning system (LGP 10.1). The focal precession test was performed with 4mm collimator and an experimental plan of four 16mm collimator shots was prepared for treatment verification of multi-fraction regimen. The prescription dose of 5Gy per fraction was delivered in four fractions. Each fraction was analyzed using EBT3 films scanned with EPSON 10000XL Scanner. Results: The measurement of 38 RCT points showed an overall positional accuracy of 0.28mm. The mean deviation of 0.28% and 0.31 % were calculated as CT and MR image distortion respectively. The radiological focus accuracy test showed its deviation from mechanical center point of 0.22mm. The profile measurement showed close agreement between TPS planned and film measured dose. At tolerance criteria of 1%/1mm gamma index analysis showed a pass rate of > 95%. Conclusion: Our results show that the newly developed multipurpose patient simulating phantom is highly suitable for the verification of fractionated stereotactic

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Lithotomy versus jack-knife position on haemodynamic parameters assessed by impedance cardiography during anorectal surgery under low dose spinal anaesthesia: a randomized controlled trial.

    PubMed

    Borodiciene, Jurgita; Gudaityte, Jurate; Macas, Andrius

    2015-05-06

    Although the prone position providing better exposure for anorectal surgery is required it can cause a reduction of cardiac output and cardiac index. The goal was to compare haemodynamic changes assessed by impedance cardiography during anorectal surgery under low-dose spinal anaesthesia in lithotomy and jack-knife position. The prospective randomized controlled study included 104, ASA I-II adult patients admitted for elective minor anorectal surgery, assigned to be performed in lithotomy (groupL, n = 52) or jack-knife position (groupJ, n = 52). After arrival to operating room the standard monitoring, impedance cardiography device was connected to the patient, and the following variables were recorded: cardiac output, cardiac index, systemic vascular resistance, stroke index at times of arrival to operating room, placement for, start and end of surgery and placement to bed. Spinal block was made in the sitting position with 4 mg of 0.5% hyperbaric bupivacaine and 10 μg of Fentanyl injected over 2 min. Comparison was based on haemodynamic changes between and inside groups over time. Student's t, chi square tests were used for statistical analysis with p < 0.05 regarded as statistically significant. The reduction of cardiac output was statistically significant after placement of the patient into the prone position: from baseline 7.4+/-1.6 to 4.9+/-1.2 after placement for and 4.7+/-1.2 at the start and end of surgery (mean +/-SD l/min). The difference of cardiac output between groups was 2.0 l/min after positioning for and the start of surgery and 1.5 l/min at the end of surgery (p < 0.05). Mean cardiac index reduced from baseline 3.9+/-0.8 to 2.6+/-0.7 and 2.4+/-0.6 (mean+/-SD l/min/m(2)) in groupJ and between groups: by 1.0 l/min/m(2) after placement for, 1.1 at the start and 0.8 at the end of surgery (p < 0.05). Systemic vascular resistance increased from baseline 1080+/-338 to 1483+/-479 after placement for, 1523+/-481 at the start and 1525

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  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. 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.

  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. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. Minimally invasive carpal tunnel decompression using the KnifeLight.

    PubMed

    Hwang, Peter Y K; Ho, Chi Long

    2007-02-01

    Carpal tunnel syndrome is a common condition causing hand pain, dysfunction, and paresthesia. Endoscopic carpal tunnel decompression offers many advantages compared with conventional open surgical decompression. However, it is equipment intensive and requires familiarity with endoscopic surgery. We review a minimally invasive technique to divide the flexor retinaculum by using a new instrument, the KnifeLight (Stryker, Kalamazoo, Michigan), which combines the advantages of the open and endoscopic methods, without the need for endoscopic set-up. Between July 2003 and April 2005, 44 consecutive patients (26 women [59%] and 18 men [36%]), with clinical signs and symptoms, as well as electrodiagnostic findings consistent with carpal tunnel syndrome, who did not respond to non-surgical treatment, underwent the new procedure. All patients were asked about scar hypertrophy, scar tenderness, and pillar pain. The Michigan Hand Outcomes Questionnaire (MHQ) was used to determine overall hand function, activities of daily living, work performance, pain, aesthetics, and satisfaction with hand function. Other preoperative testing included grip strength and lateral pinch strength. Grip strength was measured using the Jamar hand dynamometer (Asimov Engineering Co., Los Angeles, CA); lateral key pinch was measured using the Jamar hydraulic pinch gauge. Postoperative evaluations were scheduled at 2 weeks, 3 months, and 6 months after the procedure. A small 10-mm incision was made in the wrist crease and a small opening was made at the transverse carpal ligament. The KnifeLight tool was inserted, and the ligament was incised completely. Follow-up evaluations with use of quantitative measurements of grip strength, pinch strength, and hand dexterity were performed at 2 weeks, 3 months, and 6 months after surgery. Fifty procedures were performed on 22 left hands (44%) and 28 right hands (56%). There were no complications related to the approach. All patients were able to use their hands

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  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. 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. 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

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. Comparison of pain and swelling after removal of oral leukoplakia with CO2 laser and cold knife: A randomized clinical trial

    PubMed Central

    López-Jornet, Pía

    2013-01-01

    Objective: The aim of this study was to compare conventional surgery with carbon dioxide (CO2) laser in patients with oral leukoplakia, and to evaluate the postoperative pain and swelling. Study design: A total of 48 patients (27 males and 21 females) with a mean age of 53.7 ± 11.7 years and diagnosed with oral leukoplakia were randomly assigned to receive treatment either with conventional surgery using a cold knife or with a CO2 laser technique. A visual analog scale (VAS) was used to score pain and swelling at different postoperative time points. Results: Pain and swelling reported by the patients was greater with the conventional cold knife than with the CO2 laser, statistically significant differences for pain and swelling were observed between the two techniques during the first three days after surgery. Followed by a gradual decrease over one week. In neither group was granuloma formation observed, and none of the patients showed malignant transformation during the period of follow-up. Conclusions: The CO2 laser causes only minimal pain and swelling, thus suggesting that it may be an alternative method to conventional surgery in treating patients with oral leukoplakia. Key words:Oral leukoplakia, treatment, laser surgery, cold knife, pain, swelling. PMID:23229239

  6. A comprehensive overview of radioguided surgery using gamma detection probe technology

    PubMed Central

    Povoski, Stephen P; Neff, Ryan L; Mojzisik, Cathy M; O'Malley, David M; Hinkle, George H; Hall, Nathan C; Murrey, Douglas A; Knopp, Michael V; Martin, Edward W

    2009-01-01

    The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology. PMID:19173715

  7. 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.

  8. 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

  9. 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

  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. 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…

  13. 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

  14. 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

  15. 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

  16. [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.

  17. 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.

  18. 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

  19. 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

  20. [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.

  1. 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

  2. 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.

  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. 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."

  5. 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

  6. 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

  7. 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.

  8. 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

  9. Feasibility of a wireless gamma probe in radioguided surgery.

    PubMed

    Park, Hye Min; Joo, Koan Sik

    2016-06-21

    Radioguided surgery through the use of a gamma probe is an established practice, and has been widely applied in the case of sentinel lymph node biopsies. A wide range of intraoperative gamma probes is commercially available. The primary characteristics of the gamma probes include their sensitivity, spatial resolution, and energy resolution. We present the results obtained from a prototype of a new wireless gamma probe. This prototype is composed of a 20 mm thick cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) inorganic scintillation crystal from Furukawa Denshi and a Hamamatsu S12572-100C multi-pixel photon counter equipped with a designed electronics. The measured performance characteristics include the energy resolution, energy linearity, angular aperture, spatial resolution and sensitivity. Measurements were carried out using (57)Co, (133)Ba, (22)Na, and (137)Cs sources. The energy resolutions for 0.122 and 0.511 MeV were 17.2% and 6.9%, respectively. The designed prototype consumes an energy of approximately 4.4 W, weighs about 310 g (including battery) having a dimension of 20 mm (D)  ×  130 mm (L).

  10. Feasibility of a wireless gamma probe in radioguided surgery

    NASA Astrophysics Data System (ADS)

    Park, Hye Min; Joo, Koan Sik

    2016-06-01

    Radioguided surgery through the use of a gamma probe is an established practice, and has been widely applied in the case of sentinel lymph node biopsies. A wide range of intraoperative gamma probes is commercially available. The primary characteristics of the gamma probes include their sensitivity, spatial resolution, and energy resolution. We present the results obtained from a prototype of a new wireless gamma probe. This prototype is composed of a 20 mm thick cerium-doped gadolinium aluminum gallium garnet (Ce:GAGG) inorganic scintillation crystal from Furukawa Denshi and a Hamamatsu S12572-100C multi-pixel photon counter equipped with a designed electronics. The measured performance characteristics include the energy resolution, energy linearity, angular aperture, spatial resolution and sensitivity. Measurements were carried out using 57Co, 133Ba, 22Na, and 137Cs sources. The energy resolutions for 0.122 and 0.511 MeV were 17.2% and 6.9%, respectively. The designed prototype consumes an energy of approximately 4.4 W, weighs about 310 g (including battery) having a dimension of 20 mm (D)  ×  130 mm (L).

  11. 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,…

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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...

  17. Evaluation of holmium laser versus cold knife in optical internal urethrotomy for the management of short segment urethral stricture.

    PubMed

    Jain, Sudhir Kumar; Kaza, Ram Chandra Murthy; Singh, Bipin Kumar

    2014-10-01

    SACHSE COLD KNIFE IS CONVENTIONALLY USED FOR OPTICAL INTERNAL URETHROTOMY INTENDED TO MANAGE URETHRAL STRICTURES AND HO: YAG laser is an alternative to it. The aim of this study was to evaluate the role of urethral stricture treatment outcomes, efficacy, and complications using cold knife and Ho: YAG (Holmium laser) for optical internal urethrotomy. In this prospective study included, 90 male patients age >18 years, with diagnosis of urethral stricture admitted for internal optical urethrotomy during April 2010 to March 2012. The patients were randomized into two groups containing 45 patients each using computer generated random number. In group A (Holmium group), internal urethrotomy was done with Holmium laser and in group B (Cold knife group) Sachse cold knife was used. Patients were followed up for 6 months after surgery in Out Patient Department on 15, 30 and 180 post-operative days. At each follow up visit physical examination, and uroflowmetry was performed along with noting complaints, if any. The peak flow rates (PFR) were compared between the two groups on each follow up. At 180 days (6 month interval) the difference between mean of PFR for Holmium and Cold knife group was statistically highly significant (P < 0.001). Complications were seen in 12.22% of cases. Both modalities are effective in providing immediate relief to patients with single and short segment (<2 cm long) urethral strictures but more sustained response was attained with Cold knife urethrotomy.

  18. 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.

  19. 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

  20. 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

  1. Optical coherence tomography image-guided smart laser knife for surgery.

    PubMed

    Katta, Nitesh; McElroy, Austin B; Estrada, Arnold D; Milner, Thomas E

    2018-03-01

    Surgical oncology can benefit from specialized tools that enhance imaging and enable precise cutting and removal of tissue without damage to adjacent structures. The combination of high-resolution, fast optical coherence tomography (OCT) co-aligned with a nanosecond pulsed thulium (Tm) laser offers advantages over conventional surgical laser systems. Tm lasers provide superior beam quality, high volumetric tissue removal rates with minimal residual thermal footprint in tissue, enabling a reduction in unwanted damage to delicate adjacent sub-surface structures such as nerves or micro-vessels. We investigated such a combined Tm/OCT system with co-aligned imaging and cutting beams-a configuration we call a "smart laser knife." A blow-off model that considers absorption coefficients and beam delivery systems was utilized to predict Tm cut depth, tissue removal rate and spatial distribution of residual thermal injury. Experiments were performed to verify the volumetric removal rate predicted by the model as a function of average power. A bench-top, combined Tm/OCT system was constructed using a 15W 1940 nm nanosecond pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30 kHz repetition rate) for removing tissue and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging. Tissue phantoms were used to demonstrate precise surgery with blood vessel avoidance. Depth imaging informed cutting/removal of targeted tissue structures by the Tm laser was performed. Laser cutting was accomplished around and above phantom blood vessels while avoiding damage to vessel walls. A tissue removal rate of 5.5 mm 3 /sec was achieved experimentally, in comparison to the model prediction of approximately 6 mm 3 /sec. We describe a system that combines OCT and laser tissue modification with a Tm laser. Simulation results of the tissue removal rate using a simple model, as a function of average power, are in good agreement with experimental

  2. Acoustic Neuroma Association

    MedlinePlus

    ... Gold Sponsor NSPC Brain & Spine Surgery Learn More Gold Sponsor University of Colorado Acoustic Neuroma Program and Rocky Mountain Gamma Knife Center Learn More Gold Sponsor USC Acoustic Neuroma Center Learn More Gold ...

  3. Measurement of Gamma-Irradiated Corneal Patch Graft Thickness After Aqueous Drainage Device Surgery.

    PubMed

    de Luna, Regina A; Moledina, Ameera; Wang, Jiangxia; Jampel, Henry D

    2017-09-01

    Exposure of the tube of an aqueous drainage device (ADD) through the conjunctiva is a serious complication of ADD surgery. Although placement of gamma-irradiated sterile cornea (GISC) as a patch graft over the tube is commonly performed, exposures still occur. To measure GISC patch graft thickness as a function of time after surgery, estimate the rate of graft thinning, and determine risk factors for graft thinning. Cross-sectional study of graft thickness using anterior segment optic coherence tomography (AS-OCT) was conducted at the Wilmer Eye Institute at Johns Hopkins Hospital. A total of 107 patients (120 eyes, 120 ADDs) 18 years or older who underwent ADD surgery at Johns Hopkins with GISC patch graft between July 1, 2010, and October 31, 2016, were enrolled. Implantation of ADD with placement of GISC patch graft over the tube. Graft thickness vs time after ADD surgery and risk factors for undetectable graft. Of the 107 patients included in the analysis, the mean (SD) age of the cohort was 64 (16.2) years, 49 (45.8%) were male, and 43 (40.2%) were African American. The mean time of measurement after surgery was 1.7 years (range, 1 day to 6 years). Thinner grafts were observed as the time after surgery lengthened (β regression coefficient, -60 µm per year since surgery; 95% CI, -80 µm to -40 µm). The odds ratio of undetectable grafts per year after ADD surgery was 2.1 (95% CI, 1.5-3.0; P < .001). Age, sex, race, type of ADD, quadrant of ADD placement, diagnosis of uveitis or dry eye, and prior conjunctival surgery were not correlated with the presence or absence of the graft. Gamma-irradiated sterile corneal patch grafts do not always retain their integrity after ADD surgery. Data from this cross-sectional study showed that on average, the longer the time after surgery, the thinner the graft. These findings suggest that placement of a GISC patch graft is no guarantee against tube exposure, and that better strategies are needed for preventing this

  4. 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.

  5. 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.

  6. Optical coherence tomography (OCT) guided smart laser knife for cancer surgery (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Katta, Nitesh; Mcelroy, Austin; Estrada, Arnold; Milner, Thomas E.

    2017-02-01

    Neurological cancer surgeries require specialized tools that enhance imaging for precise cutting and removal of tissue without damaging adjacent neurological structures. The novel combination of high-resolution fast optical coherence tomography (OCT) alongside short pulsed nanosecond thulium (Tm) lasers offers stark advantages utilizing the superior beam quality, high volumetric tissue removal rates of thulium lasers with minimal residual thermal footprint in the tissue and avoiding damage to delicate sub-surface structures (e.g., nerves and microvessels); which has not been showcased before. A bench-top system is constructed, using a 15W 1940nm nanosecond pulsed Tm fiber laser (500uJ pulse energy, 100ns pulse duration, 30kHz repetition rate) for removing tissue and a swept source laser (1310±70nm, 100kHz sweep rate) is utilized for OCT imaging, forming a combined Tm/OCT system - a smart laser knife. The OCT image-guidance informs the Tm laser for cutting/removal of targeted tissue structures. Tissue phantoms were constructed to demonstrate surgical incision with blood vessel avoidance on the surface where 2mm wide 600um deep cuts are executed around the vessel using OCT to guide the procedure. Cutting up to delicate subsurface blood vessels (2mm deep) is demonstrated while avoiding damage to their walls. A tissue removal rate of 5mm^3/sec is obtained from the bench-top system. We constructed a blow-off model to characterize Tm cut depths taking into account the absorption coefficients and beam delivery systems to compute Arrhenius damage integrals. The model is used to compare predicted tissue removal rate and residual thermal injury with experimental values in response to Tm laser-tissue modification.

  7. 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.

  8. Two cases of electrocautery incision therapy using an insulated-tip knife for treatment of symptomatic benign short-segment colonic stenosis following colonic resection.

    PubMed

    Kwon, Jang Hoon; Han, Koon Hee; Kim, Moon Ho; Jang, Woo Sung; Yun, Jung Ho; Song, Yun A; Park, Jong Kyu; Cheon, Gab Jin

    2014-09-25

    Anastomotic stenosis of the colon is not an uncommon finding; however, its frequency varies from one study to another. Traditionally, postoperative colonic stenosis is managed surgically. However, endoscopic therapy has recently become the preferred treatment modality over traditional surgery. Good short-term success has been achieved with use of endoscopic balloon dilation; however, restenosis may occur over time in 14% to 25% of patients. The current report showed the effectiveness and usefulness of an insulated-tip knife (IT-knife) for electrocautery therapy of a patient with symptomatic anastomotic colonic stenosis.

  9. Surgical technique for en bloc transurethral resection of bladder tumour with a Hybrid Knife(®).

    PubMed

    Islas-García, J J O; Campos-Salcedo, J G; López-Benjume, B I; Torres-Gómez, J J; Aguilar-Colmenero, J; Martínez-Alonso, I A; Gil-Villa, S A

    2016-05-01

    Bladder cancer is the second most common malignancy of the urinary tract and the 9th worldwide. Latin American has an incidence of 5.6 per 100,000 inhabitants per year. Seventy-five percent of newly diagnosed cases are nonmuscle invasive bladder cancer, and 25% of cases present as muscle invasive. The mainstay of treatment for nonmuscle invasive bladder cancer is loop transurethral resection. In 2013, the group led by Dr Mundhenk of the University Hospital of Tübingen, Germany, was the first to describe the Hybrid Knife(®) equipment for performing en bloc bladder tumour resection, with favourable functional and oncological results. To describe the surgical technique of en bloc bladder tumour resection with a Hybrid Knife(®) as an alternative treatment for nonmuscle invasive bladder tumours. A male patient was diagnosed by urotomography and urethrocystoscopy with a bladder tumour measuring 2×1cm on the floor. En bloc transurethral resection of the bladder tumour was performed with a Hybrid Knife(®). Surgery was performed for 35min, with 70 watts for cutting and 50 watts for coagulation, resecting and evacuating en bloc the bladder tumour, which macroscopically included the muscle layer of the bladder. There were no complications. The technique of en bloc bladder tumour resection with Hybrid Knife(®) is an effective alternative to bipolar loop transurethral resection. Resection with a Hybrid Knife(®) is a procedure with little bleeding and good surgical vision and minimises the risk of bladder perforation and tumour implants. The procedure facilitates determining the positivity of the neoplastic process, vascular infiltration and bladder muscle invasion in the histopathology study. Copyright © 2015 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. 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

  11. 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

  12. [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.

  13. 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.

  14. 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.

  15. Is the lateral jack-knife position responsible for cases of transient neurapraxia?

    PubMed

    Molinares, Diana Margarita; Davis, Timothy T; Fung, Daniel A; Liu, John Chung-Liang; Clark, Stephen; Daily, David; Mok, James M

    2016-01-01

    The lateral jack-knife position is often used during transpsoas surgery to improve access to the spine. Postoperative neurological signs and symptoms are very common after such procedures, and the mechanism is not adequately understood. The objective of this study is to assess if the lateral jack-knife position alone can cause neurapraxia. This study compares neurological status at baseline and after positioning in the 25° right lateral jack-knife (RLJK) and the right lateral decubitus (RLD) position. Fifty healthy volunteers, ages 21 to 35, were randomly assigned to one of 2 groups: Group A (RLD) and Group B (RLJK). Motor and sensory testing was performed prior to positioning. Subjects were placed in the RLD or RLJK position, according to group assignment, for 60 minutes. Motor testing was performed immediately after this 60-minute period and again 60 minutes thereafter. Sensory testing was performed immediately after the 60-minute period and every 15 minutes thereafter, for a total of 5 times. Motor testing was performed by a physical therapist who was blinded to group assignment. A follow-up call was made 7 days after the positioning sessions. Motor deficits were observed in the nondependent lower limb in 100% of the subjects in Group B, and no motor deficits were seen in Group A. Statistically significant differences (p < 0.05) were found between the 2 groups with respect to the performance on the 10-repetition maximum test immediately immediately and 60 minutes after positioning. Subjects in Group B had a 10%-70% (average 34.8%) decrease in knee extension strength and 20%-80% (average 43%) decrease in hip flexion strength in the nondependent limb. Sensory abnormalities were observed in the nondependent lower limb in 98% of the subjects in Group B. Thirty-six percent of the Group B subjects still exhibited sensory deficits after the 60-minute recovery period. No symptoms were reported by any subject during the follow-up calls 7 days after positioning. Twenty

  16. [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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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...

  3. 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

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  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. 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.

  17. 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.

  18. 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

  19. Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife: A pilot animal study

    PubMed Central

    Jiang, Sheng-Jun; Shi, Hong; Swar, Gyanendra; Wang, Hai-Xia; Liu, Xiao-Jing; Wang, Yong-Guang

    2013-01-01

    AIM: To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model. METHODS: Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy was performed on three non-survival pigs, by transumbilical approach, using a water-jet hybrid-knife. Under general anesthesia, the following steps detailed the procedure: (1) incision of the umbilicus followed by the passage of a double-channel flexible endsocope through an overtube into the peritoneal cavity; (2) establishment of pneumoperitoneum; (3) abdominal exploration; (4) endoscopic cholecystectomy: dissection of the gallbladder performed using water jet equipment, ligation of the cystic artery and duct conducted using nylon loops; and (5) necropsy with macroscopic evaluation. RESULTS: Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig, with minor bleedings. The dissection times were 137 and 42 min, respectively. The total operation times were 167 and 69 min, respectively. And the lengths of resected specimen were 6.5 and 6.1 cm, respectively. Instillation of the fluid into the gallbladder bed produced edematous, distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops. There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case, leading to the operation failure. CONCLUSION: Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation. PMID:24187461

  20. Trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife: a pilot animal study.

    PubMed

    Jiang, Sheng-Jun; Shi, Hong; Swar, Gyanendra; Wang, Hai-Xia; Liu, Xiao-Jing; Wang, Yong-Guang

    2013-10-28

    To investigate the feasibility and safety of Natural orifice trans-umbilical endoscopic cholecystectomy with a water-jet hybrid-knife in a non-survival porcine model. Pure natural orifice transluminal endoscopic surgery (NOTES) cholecystectomy was performed on three non-survival pigs, by transumbilical approach, using a water-jet hybrid-knife. Under general anesthesia, the following steps detailed the procedure: (1) incision of the umbilicus followed by the passage of a double-channel flexible endoscope through an overtube into the peritoneal cavity; (2) establishment of pneumoperitoneum; (3) abdominal exploration; (4) endoscopic cholecystectomy: dissection of the gallbladder performed using water jet equipment, ligation of the cystic artery and duct conducted using nylon loops; and (5) necropsy with macroscopic evaluation. Transumbilical endoscopic cholecystectomy was successfully completed in the first and third pig, with minor bleedings. The dissection times were 137 and 42 min, respectively. The total operation times were 167 and 69 min, respectively. And the lengths of resected specimen were 6.5 and 6.1 cm, respectively. Instillation of the fluid into the gallbladder bed produced edematous, distended tissue making separation safe and easy. Reliable ligation using double nylon loops insured the safety of cutting between the loops. There were no intraoperative complications or hemodynamic instability. Uncontrolled introperative bleeding occurred in the second case, leading to the operation failure. Pure NOTES trans-umbilical cholecystectomy with a water-jet hybrid-knife appears to be feasible and safe. Further investigation of this technique with long-term follow-up in animals is needed to confirm the preliminary observation.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Equity under the knife: justice and evidence in surgery.

    PubMed

    Rogers, Wendy; Degeling, Christopher; Townley, Cynthia

    2014-03-01

    Surgery is an increasingly common and expensive mode of medical intervention. The ethical dimensions of the surgeon-patient relationship, including respect for personal autonomy and informed consent, are much discussed; but broader equity issues have not received the same attention. This paper extends the understanding of surgical ethics by considering the nature of evidence in surgery and its relationship to a just provision of healthcare for individuals and their populations. © 2012 John Wiley & Sons Ltd.

  6. 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.

  7. 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.

  8. 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

  9. 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…

  10. [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.

  11. 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

  12. 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.

  13. 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...

  14. 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

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 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.

  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. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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

  3. 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.

  4. [Treatment of trigger finger with located needle knife].

    PubMed

    Zhang, Qi-Feng; Yang, Jiang; Xi, Sheng-Hua

    2016-07-25

    To investigate the clinical effects of located needle knife in the treatment of trigger finger. The clinical data of 133 patients(145 fingers) with trigger finger underwent treatment with located needle knife from September 2010 to March 2014 were retrospectively analyzed. There were 37 males(40 fingers) and 96 females (105 fingers), aged from 18 to 71 years old with a mean of 51.8 years. Course of disease was from 1 to 19 months with an average of 8.2 months. Affected fingers included 82 thumbs, 12 index fingers, 11 middle fingers, 36 ring fingers, and 4 little fingers. According to the standard of Quinnell grade, 42 fingers were grade III, 92 fingers were grade IV, and 11 fingers were grade V. Firstly the double pipe gab was put into the distal edge of hypertrophic tendon sheath, then small knife needle was used to release the sheath proximally along the tendon line direction. The informations of wound healing and nerve injury, postoperative finger function, finger pain at 6 months were observed. The operation time was from 8 to 25 min with an average of 9.8 min. All the patients were followed up from 6 to 26 months with an average of 12.5 months. No complications such as the wound inflammation and seepage, vascular or nerve injuries were found. According to the standard of Quinnell grade, 123 fingers got excellent results, 15 good, 7 poor. It's a good choice to treat trigger finger with located needle knife in advantage of minimal invasion, simple safe operation, and it should be promoted in clinic.

  5. A retracting wire knife for cutting fiber bundles and making sheet lesions of brain tissue.

    PubMed

    Shibata, M; Russell, I S

    1979-07-01

    A retracting knife which has two cutting wires for the transection of fiber bundles is described. The knife holds the fiber bundles of the stria terminalis between the two cutting wires and transects them by a shearing movement as the wires close. In addition, the feasability of such a knife producing a sheet lesion around the n. caudatus is also described.

  6. Novel design and sensitivity analysis of displacement measurement system utilizing knife edge diffraction for nanopositioning stages.

    PubMed

    Lee, ChaBum; Lee, Sun-Kyu; Tarbutton, Joshua A

    2014-09-01

    This paper presents a novel design and sensitivity analysis of a knife edge-based optical displacement sensor that can be embedded with nanopositioning stages. The measurement system consists of a laser, two knife edge locations, two photodetectors, and axillary optics components in a simple configuration. The knife edge is installed on the stage parallel to its moving direction and two separated laser beams are incident on knife edges. While the stage is in motion, the direct transverse and diffracted light at each knife edge is superposed producing interference at the detector. The interference is measured with two photodetectors in a differential amplification configuration. The performance of the proposed sensor was mathematically modeled, and the effect of the optical and mechanical parameters, wavelength, beam diameter, distances from laser to knife edge to photodetector, and knife edge topography, on sensor outputs was investigated to obtain a novel analytical method to predict linearity and sensitivity. From the model, all parameters except for the beam diameter have a significant influence on measurement range and sensitivity of the proposed sensing system. To validate the model, two types of knife edges with different edge topography were used for the experiment. By utilizing a shorter wavelength, smaller sensor distance and higher edge quality increased measurement sensitivity can be obtained. The model was experimentally validated and the results showed a good agreement with the theoretically estimated results. This sensor is expected to be easily implemented into nanopositioning stage applications at a low cost and mathematical model introduced here can be used for design and performance estimation of the knife edge-based sensor as a tool.

  7. Pleuroscopic punch biopsy using insulated-tip diathermic knife-2 for the diagnosis of desmoplastic malignant mesothelioma.

    PubMed

    Masai, Kyohei; Sasada, Shinji; Izumo, Takehiro; Taniyama, Tomoko; Nakamura, Yukiko; Chavez, Christine; Sakurai, Hiroyuki; Tsuta, Koji; Tsuchida, Takaaki

    2013-10-01

    Desmoplastic malignant mesothelioma (DMM) is a rare subtype of malignant pleural mesothelioma (MPM) and is often difficult to distinguish from pleural fibrosis and reactive mesothelial hyperplasia, especially if the biopsy samples are small. We performed full-thickness pleural biopsy on a lesion suspected to be DMM using an insulated-tip diathermic knife-2 (IT knife-2) during flex-rigid pleuroscopy. IT knife-2 is a novel electrosurgical device for endoscopic submucosal dissection in the early gastrointestinal cancer. It consists of a needle knife with 3 short blades at the distal end attached to an insulated ceramic tip. A 54-year-old man presenting with chest wall mass and thickened pleura, in whom a computed tomography-guided percutaneous needle aspiration had remained negative, underwent flex-rigid pleuroscopy for definitive diagnosis. While applying electric current, we used the IT knife-2 to incise the pleura in a circular shape just above the endothoracic fascia. The incised pleura was removed by forceps and examined pathologically. The microscopic examination was compatible with DMM. We discovered that pleuroscopic punch biopsy using IT knife-2 can diagnose DMM. Use of IT knife-2 during flex-rigid pleuroscopy can obtain sufficient samples from densely thickened pleura, which is difficult to diagnose with small biopsies.

  8. 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.

  9. Submillisecond Optical Knife-Edge Testing

    NASA Technical Reports Server (NTRS)

    Thurlow, P.

    1983-01-01

    Fast computer-controlled sampling of optical knife-edge response (KER) signal increases accuracy of optical system aberration measurement. Submicrosecond-response detectors in optical focal plane convert optical signals to electrical signals converted to digital data, sampled and feed into computer for storage and subsequent analysis. Optical data are virtually free of effects of index-of-refraction gradients.

  10. 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

  11. Experimental study of hybrid-knife endoscopic submucosal dissection (ESD) versus standard ESD in a Western country.

    PubMed

    De-la-Peña, Joaquín; Calderón, Ángel; Esteban, José Miguel; López-Rosés, Leopoldo; Martínez-Ares, David; Nogales, Óscar; Orive-Calzada, Aitor; Rodríguez, Sarbelio; Sánchez-Hernández, Eloy; Vila, Juan; Fernández-Esparrach, Gloria

    2014-02-01

    Endoscopic submucosal dissection (ESD) is an effective but time-consuming treatment for early neoplasia that requires a high level of expertise. The objective of this study was to assess the efficacy and learning curve of gastric ESD with a hybrid knife with high pressure water jet and to compare with standard ESD. We performed a prospective non survival animal study comparing hybrid-knife and standard gastric ESD. Variables recorded were: Number of en-bloc ESD, number of ESD with all marks included (R0), size of specimens, time and speed of dissection and adverse events. Ten endoscopists performed a total of 50 gastric ESD (30 hybrid-knife and 20 standard). Forty-six (92 %) ESD were en-bloc and 25 (50 %) R0 (hybrid-knife: n = 13, 44 %; standard: n = 16, 80 %; p = 0.04). Hybrid-knife ESD was faster than standard (time: 44.6 +/- 21.4 minutes vs. 68.7 +/- 33.5 minutes; p = 0.009 and velocity: 20.8 +/- 9.2 mm(2)/min vs. 14.3 +/- 9.3 mm(2)/min (p = 0.079). Adverse events were not different. There was no change in speed with any of two techniques (hybrid-knife: From 20.33 +/- 15.68 to 28.18 +/- 20.07 mm(2)/min; p = 0.615 and standard: From 6.4 +/- 0.3 to 19.48 +/- 19.21 mm(2)/min; p = 0.607). The learning curve showed a significant improvement in R0 rate in the hybrid-knife group (from 30 % to 100 %). despite the initial performance of hybrid-knife ESD is worse than standard ESD, the learning curve with hybrid knife ESD is short and is associated with a rapid improvement. The introduction of new tools to facilitate ESD should be implemented with caution in order to avoid a negative impact on the results.

  12. Outcome of Microscopic Transsphenoidal Surgery in Cushing Disease: A Case Series of 96 Patients.

    PubMed

    Shirvani, Manochehr; Motiei-Langroudi, Rouzbeh; Sadeghian, Homa

    2016-03-01

    To analyze the results of transsphenoidal surgery in patients with Cushing disease and outcome. Retrospective analysis of the records of 96 patients with Cushing disease from 1997 to 2012. There were 73 females and 23 males, with a mean follow-up of 44 months (range, 3-13 years). The sex ratio was significantly different in children and teenagers versus adults. Magnetic resonance imaging showed microadenoma, macroadenoma, and no adenoma in 66, 18, and 12 patients, respectively. There was no surgical mortality. Early remission (normal 24-hour urinary free cortisol and basal serum cortisol <5 μg/dL) was achieved in 94.8%. Regression analysis showed that only tumor size, cavernous sinus extension, and tumor consistency influenced remission. Recurrence was seen in 21.9%. Regression analysis showed that age, preoperative basal cortisol levels, and follow-up duration influenced recurrence. Correlation analysis showed that there was a significant negative correlation between patient age and the follow-up period. After detection of recurrence, 17 patients underwent repeat transsphenoidal surgery that resulted in remission in 12 patients (70.6%). The other 5 patients were referred for gamma knife radiosurgery or bilateral adrenalectomy. Transsphenoidal surgery is a safe and highly efficient procedure in the treatment of Cushing disease. Macroadenomas, cavernous sinus invasion, and harder tumor consistencies, however, are associated with lower remission rates (higher disease persistence) and younger age, higher preoperative cortisol levels, and longer follow-up periods are associated with higher recurrence. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Establishing a process of irradiating small animal brain using a CyberKnife and a microCT scanner

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

    Kim, Haksoo; Welford, Scott; Fabien, Jeffrey

    2014-02-15

    Purpose: Establish and validate a process of accurately irradiating small animals using the CyberKnife G4 System (version 8.5) with treatment plans designed to irradiate a hemisphere of a mouse brain based on microCT scanner images. Methods: These experiments consisted of four parts: (1) building a mouse phantom for intensity modulated radiotherapy (IMRT) quality assurance (QA), (2) proving usability of a microCT for treatment planning, (3) fabricating a small animal positioning system for use with the CyberKnife's image guided radiotherapy (IGRT) system, and (4)in vivo verification of targeting accuracy. A set of solid water mouse phantoms was designed and fabricated, withmore » radiochromic films (RCF) positioned in selected planes to measure delivered doses. After down-sampling for treatment planning compatibility, a CT image set of a phantom was imported into the CyberKnife treatment planning system—MultiPlan (ver. 3.5.2). A 0.5 cm diameter sphere was contoured within the phantom to represent a hemispherical section of a mouse brain. A nude mouse was scanned in an alpha cradle using a microCT scanner (cone-beam, 157 × 149 pixels slices, 0.2 mm longitudinal slice thickness). Based on the results of our positional accuracy study, a planning treatment volume (PTV) was created. A stereotactic body mold of the mouse was “printed” using a 3D printer laying UV curable acrylic plastic. Printer instructions were based on exported contours of the mouse's skin. Positional reproducibility in the mold was checked by measuring ten CT scans. To verify accurate dose delivery in vivo, six mice were irradiated in the mold with a 4 mm target contour and a 2 mm PTV margin to 3 Gy and sacrificed within 20 min to avoid DNA repair. The brain was sliced and stained for analysis. Results: For the IMRT QA using a set of phantoms, the planned dose (6 Gy to the calculation point) was compared to the delivered dose measured via film and analyzed using Gamma analysis (3% and 3 mm

  14. A cross-sectional study of knife injuries at a London major trauma centre.

    PubMed

    Pallett, J R; Sutherland, E; Glucksman, E; Tunnicliff, M; Keep, J W

    2014-01-01

    No national recording systems for knife injuries exist in the UK. Understanding the true size and nature of the problem of knife injuries is the first stage in reducing the burden of this injury. The aim of this study was to survey every knife injury seen in a single inner city emergency department (ED) over a one-year period. A cross-sectional observational study was performed of all patients attending with a knife injury to the ED of a London major trauma centre in 2011. Demographic characteristics, patterns of injury, morbidity and mortality data were collected. A total of 938 knife injuries were identified from 127,191 attendances (0.77% of all visits) with a case fatality rate of 0.53%. A quarter (24%) of the major trauma team's caseload was for knife injuries. Overall, 44% of injuries were selfreported as assaults, 49% as accidents and 8% as deliberate self-harm. The highest age specific incident rate occurred in the 16-24 year age category (263/100,000). Multiple injuries were seen in 19% of cases, of which only 81% were recorded as assaults. The mean length of stay for those admitted to hospital was 3.04 days. Intrathoracic injury was seen in 26% of cases of chest trauma and 24% of abdominal injuries had a second additional chest injury. Violent intentional injuries are a significant contributory factor to the workload of the major trauma team at this centre. This paper contributes to a more comprehensive understanding of the nature of these injuries seen in the ED.

  15. Removing seed coat fragments with a lint cleaner grid bar air knife

    USDA-ARS?s Scientific Manuscript database

    Seed coat fragments (SCF) in ginned lint cause spinning problems at the textile mill and undesirable defects in finished goods. Work continued on developing an air knife that may help remove SCF from ginned lint. The air knife is mounted on the 1st lint cleaner grid bar of a saw-type lint cleaner,...

  16. Splash M-knife versus Flush Knife BT in the technical outcomes of endoscopic submucosal dissection for early gastric cancer: a propensity score matching analysis.

    PubMed

    Esaki, Mitsuru; Suzuki, Sho; Hayashi, Yasuyo; Yokoyama, Azusa; Abe, Shuichi; Hosokawa, Taizo; Ogino, Haruei; Akiho, Hirotada; Ihara, Eikichi; Ogawa, Yoshihiro

    2018-02-27

    Endoscopic submucosal dissection (ESD) is a standard treatment for early gastric cancer. A new multi-functional ESD device was developed to achieve complete ESD with a single device. A metal plate attached to its distal sheath achieves better hemostasis during the procedure than the other needle-knife device, Flush Knife BT®, that has been conventionally used. The aim of this study was to compare the technical outcomes of ESD for early gastric cancer using the Splash M-Knife® with those using the Flush Knife BT. We conducted a retrospective review of the case records of 149 patients with early gastric cancer treated with ESD using the needle-type ESD knives between January 2012 and August 2016 at Kitakyushu Municipal Medical Center. Lesions treated with ESD using the Splash M-knife (ESD-M) and the Flush Knife BT (ESD-F) were compared. Multivariate analyses and propensity score matching were used to compensate for the differences in age, gender, underlying disease, antithrombotic drug use, lesion location, lesion position, macroscopic type, tumor size, presence of ulceration, operator level and types of electrosurgical unit used. The primary endpoint was the requirement to use hemostatic forceps in the two groups. The secondary endpoints of procedure time, en bloc and complete resection rates, and adverse events rates were evaluated for the two groups. There were 73 patients in the ESD-M group, and 76 patients in the ESD-F group. Propensity score matching analysis created 45 matched pairs. Adjusted comparisons between the two groups showed a significantly lower usage rate of hemostatic forceps in the ESD-M group than in the ESD-F group (6.7% vs 84.4%, p < 0.001). Treatment outcomes showed an en bloc resection rate of 100% in both groups; complete resection rate of 95.6% vs 100%, p = 0.49; median procedure time of 74.0 min vs 71.0 min, p = 0.90; post-procedure bleeding of 2.2% vs 2.2%, p = 1, in the ESD-M and ESD-F groups, respectively. There were

  17. 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.

  18. 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

  19. SU-E-T-366: Estimation of Whole Body Dose From Cranial Irradiation From C and Perfexion Series Gamma Knife Units

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

    Srivastava, S; Indiana University School of Medicine, Indianapolis, IN, University Hospitals Case Medical Center, Cleaveland, OH; Andersen, A

    2015-06-15

    Purpose: The Leksell Gamma Knife (GK) B & C series contains 201 Cobalt-60 sources with a helmet. The new model, Perfexion uses 192 Cobalt-60 sources without a helmet; using IRIS system for collimation and stereotactic guidance to deliver SRS to brain tumors. Relative dose to extracranial organs at risk (OARs) is measured in phantom in this study for Perfexion and C-series GK. Materials & Methods: Measurements were performed in a Rando anthropomorphic phantom on both systems using a large ion chamber (Keithley-175) for each collimator. The Keithley-175 cc ion chamber was sandwiched between phantom slices at various locations in themore » phantom to correspond to different extracranial OARs (thyroid, heart, kidney, ovary and testis, etc.) The dose measurement was repeated with OSL detectors for each position and collimator. Results: A large variation is observed in the normalized dose between these two systems. The dose beyond the housing falls off exponentially for Perfexion. Dose beyond the C-series GK housing falls off exponentially from 0–20cm then remains relatively constant from 20–40cm and again falls off with distance but less rapidly. The variation of extracranial dose with distance for each collimator is found to be parallel to each other for both systems. Conclusion: Whole body dose is found to vary significantly between these systems. It is important to measure the extracranial dose, especially for young patients. It is estimated that dose falls off exponentially from the GK housing and is about 1% for large collimators at 75 cm. The dose is two-orders of magnitude smaller for the 4mm collimator. However, this small dose for patient may be significant radiologically.« less

  20. Dosimetric comparison between cone/Iris-based and InCise MLC-based CyberKnife plans for single and multiple brain metastases.

    PubMed

    Jang, Si Young; Lalonde, Ron; Ozhasoglu, Cihat; Burton, Steven; Heron, Dwight; Huq, M Saiful

    2016-09-08

    We performed an evaluation of the CyberKnife InCise MLC by comparing plan qualities for single and multiple brain lesions generated using the first version of InCise MLC, fixed cone, and Iris collimators. We also investigated differences in delivery efficiency among the three collimators. Twenty-four patients with single or multiple brain mets treated previously in our clinic on a CyberKnife M6 using cone/Iris collimators were selected for this study. Treatment plans were generated for all lesions using the InCise MLC. Number of monitor units, delivery time, target coverage, conformity index, and dose falloff were compared between MLC- and clinical cone/Iris-based plans. Statistical analysis was performed using the non-parametric Wilcoxon-Mann-Whitney signed-rank test. The planning accuracy of the MLC-based plans was validated using chamber and film measurements. The InCise MLC-based plans achieved mean dose and target coverage comparable to the cone/Iris-based plans. Although the conformity indices of the MLC-based plans were slightly higher than those of the cone/Iris-based plans, beam delivery time for the MLC-based plans was shorter by 30% ~ 40%. For smaller targets or cases with OARs located close to or abutting target volumes, MLC-based plans provided inferior dose conformity compared to cone/Iris-based plans. The QA results of MLC-based plans were within 5% absolute dose difference with over 90% gamma passing rate using 2%/2 mm gamma criteria. The first version of InCise MLC could be a useful delivery modality, especially for clinical situations for which delivery time is a limiting factor or for multitarget cases. © 2016 The Authors.

  1. A cross-sectional study of knife injuries at a London major trauma centre

    PubMed Central

    Sutherland, E; Glucksman, E; Tunnicliff, M; Keep, JW

    2014-01-01

    INTRODUCTION No national recording systems for knife injuries exist in the UK. Understanding the true size and nature of the problem of knife injuries is the first stage in reducing the burden of this injury. The aim of this study was to survey every knife injury seen in a single inner city emergency department (ED) over a one-year period. METHODS A cross-sectional observational study was performed of all patients attending with a knife injury to the ED of a London major trauma centre in 2011. Demographic characteristics, patterns of injury, morbidity and mortality data were collected. RESULTS A total of 938 knife injuries were identified from 127,191 attendances (0.77% of all visits) with a case fatality rate of 0.53%. A quarter (24%) of the major trauma team’s caseload was for knife injuries. Overall, 44% of injuries were selfreported as assaults, 49% as accidents and 8% as deliberate self-harm. The highest age specific incident rate occurred in the 16–24 year age category (263/100,000). Multiple injuries were seen in 19% of cases, of which only 81% were recorded as assaults. The mean length of stay for those admitted to hospital was 3.04 days. Intrathoracic injury was seen in 26% of cases of chest trauma and 24% of abdominal injuries had a second additional chest injury. CONCLUSIONS Violent intentional injuries are a significant contributory factor to the workload of the major trauma team at this centre. This paper contributes to a more comprehensive understanding of the nature of these injuries seen in the ED. PMID:24417825

  2. 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

  3. 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

  4. 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.

  5. A continuous arc delivery optimization algorithm for CyberKnife m6.

    PubMed

    Kearney, Vasant; Descovich, Martina; Sudhyadhom, Atchar; Cheung, Joey P; McGuinness, Christopher; Solberg, Timothy D

    2018-06-01

    This study aims to reduce the delivery time of CyberKnife m6 treatments by allowing for noncoplanar continuous arc delivery. To achieve this, a novel noncoplanar continuous arc delivery optimization algorithm was developed for the CyberKnife m6 treatment system (CyberArc-m6). CyberArc-m6 uses a five-step overarching strategy, in which an initial set of beam geometries is determined, the robotic delivery path is calculated, direct aperture optimization is conducted, intermediate MLC configurations are extracted, and the final beam weights are computed for the continuous arc radiation source model. This algorithm was implemented on five prostate and three brain patients, previously planned using a conventional step-and-shoot CyberKnife m6 delivery technique. The dosimetric quality of the CyberArc-m6 plans was assessed using locally confined mutual information (LCMI), conformity index (CI), heterogeneity index (HI), and a variety of common clinical dosimetric objectives. Using conservative optimization tuning parameters, CyberArc-m6 plans were able to achieve an average CI difference of 0.036 ± 0.025, an average HI difference of 0.046 ± 0.038, and an average LCMI of 0.920 ± 0.030 compared with the original CyberKnife m6 plans. Including a 5 s per minute image alignment time and a 5-min setup time, conservative CyberArc-m6 plans achieved an average treatment delivery speed up of 1.545x ± 0.305x compared with step-and-shoot plans. The CyberArc-m6 algorithm was able to achieve dosimetrically similar plans compared to their step-and-shoot CyberKnife m6 counterparts, while simultaneously reducing treatment delivery times. © 2018 American Association of Physicists in Medicine.

  6. Scissor-type knife significantly improves self-completion rate of colorectal endoscopic submucosal dissection: Single-center prospective randomized trial.

    PubMed

    Yamashina, Takeshi; Takeuchi, Yoji; Nagai, Kengo; Matsuura, Noriko; Ito, Takashi; Fujii, Mototsugu; Hanaoka, Noboru; Higashino, Koji; Uedo, Noriya; Ishihara, Ryu; Iishi, Hiroyasu

    2017-05-01

    Colorectal endoscopic submucosal dissection (C-ESD) is recognized as a difficult procedure. Recently, scissors-type knives were launched to reduce the difficulty of C-ESD. The aim of this study was to evaluate the efficacy and safety of the combined use of a scissors-type knife and a needle-type knife with a water-jet function (WJ needle-knife) for C-ESD compared with using the WJ needle-knife alone. This was a prospective randomized controlled trial in a referral center. Eighty-five patients with superficial colorectal neoplasms were enrolled and randomly assigned to undergo C-ESD using a WJ needle-knife alone (Flush group) or a scissor-type knife-supported WJ needle-knife (SB Jr group). Procedures were conducted by two supervised residents. Primary endpoint was self-completion rate by the residents. Self-completion rate was 67% in the SB Jr group, which was significantly higher than that in the Flush group (39%, P = 0.01). Even after exclusion of four patients in the SB Jr group in whom C-ESD was completed using the WJ needle-knife alone, the self-completion rate was significantly higher (63% vs 39%; P = 0.03). Median procedure time among the self-completion cases did not differ significantly between the two groups (59 vs 51 min; P = 0.14). No fatal adverse events were observed in either group. In this single-center phase II trial, scissor-type knife significantly improved residents' self-completion rate for C-ESD, with no increase in procedure time or adverse events. A multicenter trial would be warranted to confirm the validity of the present study. © 2016 Japan Gastroenterological Endoscopy Society.

  7. Increased expression of EMMPRIN and VEGF in the rat brain after gamma irradiation.

    PubMed

    Wei, Ming; Li, Hong; Huang, Huiling; Xu, Desheng; Zhi, Dashi; Liu, Dong; Zhang, Yipei

    2012-03-01

    The extracellular matrix metalloproteinase inducer (EMMPRIN) has been known to play a key regulatory role in pathological angiogenesis. A elevated activation of vascular endothelial growth factor (VEGF) following radiation injury has been shown to mediate blood-brain barrier (BBB) breakdown. However, the roles of EMMPRIN and VEGF in radiation-induced brain injury after gamma knife surgery (GKS) are not clearly understood. In this study, we investigated EMMPRIN changes in a rat model of radiation injury following GKS and examined potential associations between EMMPRIN and VEGF expression. Adult male rats were subjected to cerebral radiation injury by GKS under anesthesia. We found that EMMPRIN and VEGF expression were markedly upregulated in the target area at 8-12 weeks after GKS compared with the control group by western blot, immunohistochemistry, and RT-PCR analysis. Immunofluorescent double staining demonstrated that EMMPRIN signals colocalized with caspase-3 and VEGF-positive cells. Our data also demonstrated that increased EMMPRIN expression was correlated with increased VEGF levels in a temporal manner. This is the first study to show that EMMPRIN and VEGF may play a role in radiation injuries of the central nervous system after GKS.

  8. Two-dimensional straightness measurement based on optical knife-edge sensing

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhong, Fenghe; Ellis, Jonathan D.

    2017-09-01

    Straightness error is a parasitic translation along a perpendicular direction to the primary displacement axis of a linear stage. The parasitic translations could be coupled into other primary displacement directions of a multi-axis platform. Hence, its measurement and compensation are critical in precision multi-axis metrology, calibration, and manufacturing. This paper presents a two-dimensional (2D) straightness measurement configuration based on 2D optical knife-edge sensing, which is simple, light-weight, compact, and easy to align. It applies a 2D optical knife-edge to manipulate the diffraction pattern sensed by a quadrant photodetector, whose output voltages could derive 2D straightness errors after a calibration process. This paper analyzes the physical model of the configuration and performs simulations and experiments to study the system sensitivity, measurement nonlinearity, and error sources. The results demonstrate that the proposed configuration has higher sensitivity and insensitive to beam's vibration, compared with the conventional configurations without using the knife-edge, and could achieve ±0.25 μ m within a ±40 μ m measurement range along a 40 mm primary axial motion.

  9. 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.

  10. 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

  11. Blurred image restoration using knife-edge function and optimal window Wiener filtering.

    PubMed

    Wang, Min; Zhou, Shudao; Yan, Wei

    2018-01-01

    Motion blur in images is usually modeled as the convolution of a point spread function (PSF) and the original image represented as pixel intensities. The knife-edge function can be used to model various types of motion-blurs, and hence it allows for the construction of a PSF and accurate estimation of the degradation function without knowledge of the specific degradation model. This paper addresses the problem of image restoration using a knife-edge function and optimal window Wiener filtering. In the proposed method, we first calculate the motion-blur parameters and construct the optimal window. Then, we use the detected knife-edge function to obtain the system degradation function. Finally, we perform Wiener filtering to obtain the restored image. Experiments show that the restored image has improved resolution and contrast parameters with clear details and no discernible ringing effects.

  12. Blurred image restoration using knife-edge function and optimal window Wiener filtering

    PubMed Central

    Zhou, Shudao; Yan, Wei

    2018-01-01

    Motion blur in images is usually modeled as the convolution of a point spread function (PSF) and the original image represented as pixel intensities. The knife-edge function can be used to model various types of motion-blurs, and hence it allows for the construction of a PSF and accurate estimation of the degradation function without knowledge of the specific degradation model. This paper addresses the problem of image restoration using a knife-edge function and optimal window Wiener filtering. In the proposed method, we first calculate the motion-blur parameters and construct the optimal window. Then, we use the detected knife-edge function to obtain the system degradation function. Finally, we perform Wiener filtering to obtain the restored image. Experiments show that the restored image has improved resolution and contrast parameters with clear details and no discernible ringing effects. PMID:29377950

  13. Radioguided Adrenal Surgery

    PubMed Central

    Deus, Javier; Millera, Alfonso; Andrés, Alejandro; Prats, Enrique; Gil, Ismael; Suarez, Manuel; Salcini, José L.; Lahoz, Manuel

    2015-01-01

    Abstract The laparoscopic adrenalectomy is considered as the procedure of choice for the treatment of adrenal hyperplasia and tumor lesions. However, some special situations may limit the use of this method due to the difficulty to locate the gland and perform the lesion excision. We analyze 2 patients of a left adrenal tumor, explaining how they have overcome the difficulties in both situations. The first case was a patient with a history of intra-abdominal surgery and the other patient suffered from severe obesity. We performed with the use of the gamma probe, and the 2 cases, was of great help to access and glandular localization. The help of gamma probe test was achieved in the surgical bed, that removal was complete. The use of the portable gamma probe facilitated the access to the left adrenal gland as well as conducting the glandular excision without delay, despite the difficulties due to the intra abdominal surgery caused by the previous surgery, and in the case of severe obesity. PMID:26426608

  14. Peroral Endoscopic Myotomy in Children: First Experience With a New Triangular Knife.

    PubMed

    Nabi, Zaheer; Ramchandani, Mohan; Chavan, Radhika; Tandan, Manu; Kalapala, Rakesh; Darisetty, Santosh; Reddy, Duvuur Nageshwar

    2018-01-01

    Peroral endoscopic myotomy (POEM) is a novel treatment modality for achalasia cardia. The procedure is technically challenging and time consuming. Recently, a new triangle tip knife (TTJ) has been introduced, which is equipped with water jet facility. In the present study, we analyzed the feasibility, safety, and efficacy of POEM in children with new triangle tip knife. We retrospectively evaluated the data of children (18 years or younger) who underwent POEM using TTJ knife at our institution. All POEM procedures were performed under general anesthesia in an endoscopy suite. Technical feasibility, safety, efficacy, and procedure duration were assessed. Ten children (4 boys, 6 girls) with mean age of 14.2 ± 2.74 (9-18) years, underwent POEM with TTJ knife. The subtypes of achalasia cardia were type I (4), type II (5), and type III (1). Two children had prior treatment with pneumatic balloon dilatation. POEM was performed via anterior route in majority of children (70%). Mean operating time was 47.6 ± 19.74 (30-98) minutes with no significant difference between anterior and posterior approaches to POEM (48.57 ± 24.01 vs 45.3 ± 3.51; P < 0.05). Four gas-related adverse events were encountered including capnoperitoneum and retroperitoneal carbon dioxide in 2 children each. Clinical success was noticed in 9 children with significant reduction in Eckardt score at 1 month after POEM (6.7 ± 1.49 vs 0.3 ± 0.48; P = 0.0001). POEM can be efficiently performed with new triangle knife equipped with water jet technique. Integration of water jet reduces procedure duration and technical difficulty with POEM.

  15. How Sharp Does a "Knife Edge" Have to Be?

    ERIC Educational Resources Information Center

    Dietz, Eric R.; Gash, Philip W.

    1994-01-01

    Describes an experiment designed to help understand the effect of the curvature of the laboratory equipment support (cylindrical rod instead of knife-edge) on the frequency of oscillation of pendula. (ZWH)

  16. Investigation of intracranial peripheral dose arising from the treatment of large lesions with Leksell GammaKnife Perfexion.

    PubMed

    Ruschin, Mark; Nordström, Håkan; Kjäll, Per; Cho, Young-Bin; Jaffray, David

    2009-06-01

    This investigation involves quantifying the extent of intracranial peripheral dose arising from simulated targets situated in the skull-base or upper-spine region using the Leksell GammaKnife Perfexion treatment unit. For each of three spherical target volumes--denoted as Vs (4 cm3), VM (18 cm3), and VL (60 cm3)--three treatment plans were manually generated, one for each of the three collimator sizes--4, 8, and 16 mm. Each of the plans was delivered to a spherical dosimetry phantom with an insert containing EBT Gafchromic film. The total dose at 70 mm from the targets' edges, %D(70 mm), was measured as a function of elevation angle and expressed as a percentage of the prescription dose. The film insert was placed centered in the median sagittal plane (Leksell X = 100) and %D(70 mm) was measured for the angular range from 0 degree (superior/along Z axis) to 90 degrees (anterior/along Y axis). For a given collimator i, the irradiation time ti to treat a spherical target of volume V using the 50% isodose line was observed to follow a power-law relationship of the form ti = Ai(V/ Vi)n where Ai was the maximum dose divided by collimator dose rate and Vi was the volume encompassed by the 50% isodose line for a single shot. The mean value of n was 0.61 (range: 0.61-0.62). Along the superior (Z) direction (angle=0 degree) and up to angles of around 30 degrees, the %D(70 mm) was always highest for the 4 mm plans, followed by the 8 mm, followed by the 16 mm. In this angular range, the maximum measured %D(70 mm) was 1.7% of the prescription dose. The intracranial peripheral dose along the superior direction (combined scatter and leakage dose) resulting from irradiation of upper-spine or base-of-skull lesions is measured to be less than 2% of the prescription dose, even for very large (60 cm3) targets. The results of this study indicate that, for a given target volume, treatment plans consisting of only 4 mm shots yield larger peripheral dose in the superior direction than 8

  17. 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

  18. [Efficacy comparison between needle-knife therapy and acupuncture-cupping for cervical spondylosis of cervical type].

    PubMed

    Cao, Li; Wang, Fan

    2014-05-01

    To compare the efficacy differences between needle-knife therapy and acupuncture-cupping for treatment of cervical spondylosis (CS) of cervical type. Sixty cases of CS were randomly divided into a needle-knife group (30 cases) and an acupuncture-cupping group (30 cases). The needle-knife therapy was applied at points among superior nuchal line of occipital bone, bilateral neck muscle, neck centerline, trapezius and medial border scapula for only once. In the acupuncture-cupping group, acupuncture was applied at Fengchi (GB 20), Fengfu (GV 16), Tianzhu (BL 10), Dazhui (GV 14), Jianjing (GB 21), Jiaji (Ex-B2, from C4 to C6), Houxi (SI 3) and Ashi point, followed by cupping on local skin, once every other day for totally six times. The score of neck stiffness and visual analogue scale (VAS) were observed before and after treatment, in follow-up of 1, 3 and 6 months after treatment in the two groups, and the efficacy was compared. In the needle-knife group, 9 cases were cured, 12 cases were markedly effective, 8 cases were effective and 1 case was failed; the total effective rate was 96.7% (29/30) and the cured and markedly effective rate was 70.0% (21/30). In the acupuncture-cupping group, 8 cases were cured, 9 cases were markedly effective, 11 cases were effective and 2 cases were failed; the total effective rate was 93.3% (28/30) and the cured and markedly effective rate was 56.7% (17/30). The difference of total effective rate in the two groups was not statistically significant (P > 0.05), but the cured and markedly effective rate of needle-knife group was significantly superior to that of acupuncture-cupping group (P < 0.05). The needle-knife therapy was significantly superior to acupuncture-cupping on improvement of neck stiffness in the follow-up of 1, 3, 6 months after treatment (P < 0.05, P < 0.001); both treatments were effective on relief of neck pain, but the needle-knife group had better effects in the follow-up of 3 and 6 months after treatment compared

  19. Characteristics of Bone Injuries Resulting from Knife Wounds Incised with Different Forces.

    PubMed

    Humphrey, Caitlin; Kumaratilake, Jaliya; Henneberg, Maciej

    2017-11-01

    The aim of this research was to experimentally determine the characteristics of incised bone wounds, which are commonly found in defense injuries. A specially constructed pivoting arm device was used to inflict wounds with controlled forces and direction. Five knives were selected to inflict the wounds on porcine forelimbs. Eight incised wounds were made per knife per force. A larger knife and a greater force caused longer and wider bone wounds. Comparisons of individual knives at the two forces produced varying results in the bone wounds. A correlation was seen between the force and the length (r = 0.69), width (r = 0.63), and depth (r = 0.57) of bone wounds. Serrated-edge and nonserrated knives can be distinguished from the appearance of the wound. The outcomes may be applicable in forensic investigations to ascertain the forces associated with incised wounds and identify the specific knife used. © 2017 American Academy of Forensic Sciences.

  20. Bark Separation During Chipping With a Parallel Knife Chipper

    Treesearch

    John R. Erickson

    1968-01-01

    Five winter-cut northern species were chipped in a frozen and unfrozen condition with a parallel knife chipper. The degree of bark separation during chipping and a relative gradation of chip size are reported.

  1. Adjustable knife cuts honeycomb material to specified depth

    NASA Technical Reports Server (NTRS)

    Rauschl, J. A.

    1966-01-01

    Calibrated, adjustable knife cuts aluminum honeycomb or other soft materials to a desired depth. The frame of the device accommodates standard commercial blades. Since the blade is always visible to the operator, the device can be used on any straight or irregular layout line.

  2. Sphincterotomy by triple lumen needle knife using guide wire in patients with Billroth II gastrectomy

    PubMed Central

    Park, Su Bum; Kim, Hyung Wook; Kang, Dae Hwan; Choi, Cheol Woong; Yoon, Ki Tae; Cho, Mong; Song, Byeong Jun

    2013-01-01

    AIM: To investigate the usefulness of a guide wire and triple lumen needle knife for removing stones in Billroth II (B-II) gastrectomy patients. METHODS: Endoscopic sphincterotomy in patients with B-II gastrectomy is challenging. We used a new guide wire technique involving sphincterotomy by triple lumen needle knife through a forward-viewing endoscopy. This technique was performed in nine patients between August 2010 and June 2012. Sphincterotomy as described above was performed. Adequate sphincterotomy, successful stone removal, and complications were investigated prospectively. RESULTS: Sphincterotomy by triple lumen needle knife using guide wire was successful in all nine patients. Sphincterotomy started towards the 4-5 o’clock direction and continued to the upper margin of the papillary roof. Complete stone removal in one session was achieved in all patients. There were no procedure related complications, such as bleeding, pancreatitis, or perforation. CONCLUSION: In patients with B-II gastrectomy, guide wire using sphincterotomy by triple lumen needle knife through a forward-viewing endoscopy seems to be an effective and safe procedure for the removal of common bile duct stones. PMID:24409069

  3. [Effect of Small Knife Needle on β-enorpin and Enkehalin Contents of Tansverse Process Syndrome of the Third Vertebra].

    PubMed

    Liu, Nai-gang; Guo, Chang-qing; Sun, Hong-mei; Li, Xiao-hong; Wu, Hai-xia; Xu, Hong

    2016-04-01

    To explore the analgesic mechanism of small knife needle for treating transverse process syndrome of the third vertebra (TPSTV) by observing peripheral and central changesof β-endorphin (β-EP) and enkephalin (ENK) contents. Totally 30 Japanese white big-ear rabbits of clean grade were divided into 5 groups according to random digit table, i.e., the normal control group, the model group, the small knife needle group, the electroacupunture (EA) group, and the small knife needle plus EA group, 6 in each group. The TPSTV model was established by inserting a piece of gelatin sponge into the left transverse process of 3rd lumbar vertebrae. Rabbits in the small knife needlegroup were intervened by small knife needle. Those in the EA group were intervened by EA at bilateralWeizhong (BL40). Those in the small knife needle plus EA group were intervened by small knife needleand EA at bilateral Weizhong (BL40). Contents of β-EP and ENK in plasma, muscle, spinal cord, and hypothalamus were determined after sample collection at day 28 after modeling. Compared with the normal control group, contents of β-EP and ENK in plasma and muscle increased significantly, and contents of β-EP and ENK in spinal cord and hypothalamus decreased significantly in the model group (P < 0.05, P < 0.01). Contents of β-EP and ENK approximated normal levels in the three treatment groups after respective treatment. Compared with the model group, the content of β-EP in muscle decreased, and contents of β-EP and ENK in hypothalamus increased in the three treatment groups after respective treatment (P < 0.05). There were no significant difference among the three treatment groups (P > 0.05). Small knife needle treatment and EA had benign regulation on peripheral and central β-EP and ENK in TPSTV rabbits. Small knife needle treatment showed better effect than that of EA.

  4. Micro knife-edge optical measurement device in a silicon-on-insulator substrate.

    PubMed

    Chiu, Yi; Pan, Jiun-Hung

    2007-05-14

    The knife-edge method is a commonly used technique to characterize the optical profiles of laser beams or focused spots. In this paper, we present a micro knife-edge scanner fabricated in a silicon-on-insulator substrate using the micro-electromechanical-system technology. A photo detector can be fabricated in the device to allow further integration with on-chip signal conditioning circuitry. A novel backside deep reactive ion etching process is proposed to solve the residual stress effect due to the buried oxide layer. Focused optical spot profile measurement is demonstrated.

  5. 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

  6. Geology of the Knife River area, North Dakota

    USGS Publications Warehouse

    Benson, William Edward

    1953-01-01

    The Knife River area, consisting of six 15-minute quadrangles, includes the lower half of the Knife River valley in west-central North Dakota. The area, in the center of the Williston Basin, is underlain by the Tongue River member of the Fort Union formation (Paleocene) and the Golden Valley formation (Eocene). The Tongue River includes beds equivalent to the Sentinel Butte shale; the Golden Valley formation, which receives its first detailed description in this report, consists of two members, a lower member of gray to white sandy kaolin clay and an upper member of cross-bedded micaceous sandstone. Pro-Tongue River rocks that crop out in southwestern North Dakota include the Ludlow member of the Fort Union formation, the Cannonball marine formation (Paleocene) and the Hell Creek, Fox Hills, and Pierre formations, all upper Cretaceous. Post-Golden Valley rocks include the White River formation (Oligocene) and gravels on an old planation surface that may be Miocene or Pliocent. Surficial deposits include glacial and fluvial deposits of Pleistocene age and alluvium, dune sand, residual silica, and landslide blocks of Recent age. Three ages of glacial deposits can be differentiated, largely on the basis of three fills, separated by unconformities, in the Knife River valley. All three are of Wisconsin age and probably represent the Iowan, Tazewell, and Mankato substages. Deposits of the Cary substage have not been identified either in the Knife River area or elsewhere in southern North Dakota. Iowan glacial deposits form the outermost drift border in North Dakota. Southwest of this border are a few scattered granite boulders that are residual from the erosion of either the White River formation or a pre-Wisconsin till. The Tazewell drift border cannot be followed in southern North Dakota. The Mankato drift border can be traced in a general way from the South Dakota State line northwest across the Missouri River and through the middle of the Knife River area. The major

  7. SRAO: optical design and the dual-knife-edge WFS

    NASA Astrophysics Data System (ADS)

    Ziegler, Carl; Law, Nicholas M.; Tokovinin, Andrei

    2016-07-01

    The Southern Robotic Adaptive Optics (SRAO) instrument will bring the proven high-efficiency capabilities of Robo-AO to the Southern-Hemisphere, providing the unique capability to image with high-angular-resolution thousands of targets per year across the entire sky. Deployed on the modern 4.1m SOAR telescope located on Cerro Tololo, the NGS AO system will use an innovative dual-knife-edge wavefront sensor, similar to a pyramid sensor, to enable guiding on targets down to V=16 with diffraction limited resolution in the NIR. The dual-knife-edge wavefront sensor can be up to two orders of magnitude less costly than custom glass pyramids, with similar wavefront error sensitivity and minimal chromatic aberrations. SRAO is capable of observing hundreds of targets a night through automation, allowing confirmation and characterization of the large number of exoplanets produced by current and future missions.

  8. Cleaning mechanism of particle contaminants on large aperture optical components by using air knife sweeping technology

    NASA Astrophysics Data System (ADS)

    Niu, Longfei; Liu, Hao; Miao, Xinxiang; Lv, Haibing; Yuan, Xiaodong; Zhou, Hai; Yao, Caizhen; Zhou, Guorui; Li, Qin

    2017-05-01

    The cleaning mechanism of optical surface particle contaminants in the light pneumatic tube was simulated based on the static equations and JKR model. Cleaning verification experiment based on air knife sweeping system and on-line monitoring system in high power laser facility was set up in order to verify the simulated results. Results showed that the removal ratio is significantly influenced by sweeping velocity and angle. The removal ratio can reach to 94.3% by using higher input pressure of the air knife, demonstrating that the air knife sweeping technology is useful for maintaining the surface cleanliness of optical elements, and thus guaranteeing the long-term stable running of the high power laser facility.

  9. Knife blade as a facial foreign body.

    PubMed

    Gardner, P A; Righi, P; Shahbahrami, P B

    1997-08-01

    This case demonstrates the unpredictability of foreign bodies in the face. The retained knife blade eluded detection on two separate examinations. The essential components to making a correct diagnosis of a foreign body following a stabbing to the face include a thorough review of the mechanism of injury, a complete head and neck examination, a high index of suspicion, and plain radiographs of the face.

  10. Measuring the resolution of uncompressed plastic sections cut using an oscillating knife ultramicrotome.

    PubMed

    Sader, Kasim; Reedy, Michael; Popp, David; Lucaveche, Carmen; Trinick, John

    2007-07-01

    Thin sections of biological tissue embedded in plastic and cut with an ultramicrotome do not generally display useful details smaller than approximately 50 A in the electron microscope. However, there is evidence that before sectioning the embedded tissue can be substantially better preserved, which suggests that cutting is when major damage and loss of resolution occurs. We show here a striking example of such damage in embedded insect flight muscle fibres. X-ray diffraction of the embedded muscle gave patterns extending to 13A, whereas sections cut from the same block showed only approximately 50 A resolution. A possible source of this damage is the substantial compression that was imposed on sections during cutting. An oscillating knife ultramicrotome eliminates the compression and it seemed possible that sections cut with such a knife would show substantially improved preservation. We used the oscillating knife to cut sections from the embedded muscle and from embedded catalase crystals. Preservation with and without oscillation was assessed in Fourier transforms of micrographs. Sections cut with the knife oscillating did not show improved preservation over those cut without. Thus compression during cutting does not appear to be the major source of damage in plastic sections, and leaves unexplained the 50 A versus 13A discrepancy between block and section preservation. The results nevertheless suggest that improvements in ultramicrotomy will be important for bringing thin-sectioning and tomography of plastic-embedded cells and tissues to the point where macromolecule shapes can be resolved.

  11. TH-AB-201-01: A Feasibility Study of Independent Dose Verification for CyberKnife

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

    Sato, A; Noda, T; Keduka, Y

    2016-06-15

    Purpose: CyberKnife irradiation is composed of tiny-size, multiple and intensity-modulated beams compared to conventional linacs. Few of the publications for Independent dose calculation verification for CyberKnife have been reported. In this study, we evaluated the feasibility of independent dose verification for CyberKnife treatment as Secondary check. Methods: The followings were measured: test plans using some static and single beams, clinical plans in a phantom and using patient’s CT. 75 patient plans were collected from several treatment sites of brain, lung, liver and bone. In the test plans and the phantom plans, a pinpoint ion-chamber measurement was performed to assess dosemore » deviation for a treatment planning system (TPS) and an independent verification program of Simple MU Analysis (SMU). In the clinical plans, dose deviation between the SMU and the TPS was performed. Results: In test plan, the dose deviations were 3.3±4.5%, and 4.1±4.4% for the TPS and the SMU, respectively. In the phantom measurements for the clinical plans, the dose deviations were −0.2±3.6% for the TPS and −2.3±4.8% for the SMU. In the clinical plans using the patient’s CT, the dose deviations were −3.0±2.1% (Mean±1SD). The systematic difference was partially derived from inverse square law and penumbra calculation. Conclusion: The independent dose calculation for CyberKnife shows −3.0±4.2% (Mean±2SD) and our study, the confidence limit was achieved within 5% of the tolerance level from AAPM task group 114 for non-IMRT treatment. Thus, it may be feasible to use independent dose calculation verification for CyberKnife treatment as the secondary check. This research is partially supported by Japan Agency for Medical Research and Development (AMED)« less

  12. Inflammatory cytokine expression following the use of bipolar electrocoagulation, ultracision harmonic scalpel and cold knife biopsy.

    PubMed

    Litta, Pietro; Saccardi, Carlo; Gizzo, Salvatore; Conte, Lorena; Ambrosi, Giulia; Sissi, Claudia; Palumbo, Manlio

    2015-08-01

    Electrical surgical devices may determine tissue damage through lateral thermal spread and activation of inflammatory processes. Several tissue effects are associated with the use of different surgical instruments. The aim of the present study was to compare tissue damage following the application of cold knife biopsy, bipolar electrocoagulation and the ultracision harmonic scalpel, through the analysis of inflammatory gene mediator expression. Three fragments of the round ligament (length 0.5 cm) were obtained from 22 females who had undergone total or subtotal laparoscopic hysterectomy using three different modes of resection: Cold knife biopsy, bipolar electrocoagulation and ultracision harmonic scalpel. The tissue fragments were examined by quantitative polymerase chain reaction (qPCR) analysis of selected cytokines. Gene expression analysis demonstrated large standard deviations due to individual variability among patients and indicated variability in the concentrations of cytokines in the three different samples. The quantity of cytokine mRNA in the cold knife biopsy samples was generally greater than those obtained by other techniques. Tumor necrosis factor-α expression was significantly higher in the sample obtained with the ultracision harmonic scalpel and bipolar electrocoagulation (P=0.033) when compared with cold knife biopsy. The inflammatory response was analyzed by the quantification of gene expression through the use of qPCR. The ultracision harmonic scalpel and bipolar electrocoagulation triggered the inflammatory cascade and resulted in an increased production of cytokines compared with cold knife biopsy.

  13. Endoscopic Submucosal Dissection Using a Novel Versatile Knife: An Animal Feasibility Study (with Video)

    PubMed Central

    Kwon, Chang-Il; Kim, Gwangil; Kim, Won Hee; Ko, Kwang Hyun; Hong, Sung Pyo; Jeong, Seok; Lee, Don Haeng

    2014-01-01

    Background/Aims In order to reduce the procedure time and the number of accessory changes during endoscopic submucosal dissection (ESD), we developed a novel versatile knife, which has the combined advantages of several conventional knives. The aim of this study was to compare the efficacy, safety, and histological quality of ESD performed using this novel versatile knife and a combination of several conventional knives. Methods This was an in vivo animal study comparing two different modalities of ESD in mini-pigs. Completion time of each resection was documented, and the resected specimens were retrieved and evaluated for completeness. To assess the quality control of the procedures and adverse events, detailed histopathological examinations were performed. Results A total of 18 specimens were dissected by ESD safely and easily (nine specimens using the new versatile knife; nine specimens by mixing conventional knives). All resections were completed as en bloc resections. There was no significant difference in procedure time between the 2 modalities (456 seconds vs. 355 seconds, p=0.258) and cutting speed (1.983 mm2/sec vs. 1.57 mm2/sec, p=1.000). The rate of adverse events and histological quality did not statistically differ between the modalities. Conclusions ESD with a versatile knife appeared to be an easy, safe, and technically efficient method. PMID:25505721

  14. A stab in the dark: Design and construction of a novel device for conducting incised knife trauma investigations and its initial test.

    PubMed

    Humphrey, Caitlin; Kumaratilake, Jaliya; Henneberg, Maciej

    2016-05-01

    Knife attacks are commonly seen in Australia and other countries. During forensic investigations the force with which a wound was inflicted is often questioned. The ability to examine resultant trauma and particular weapons at different forces with an experimental device may lead to better interpretations of knife wounds. The objective of this study is to design, construct and test a device to analyse the characteristics and forces involved in knife attacks, particularly incised wounds. The mechanical variables (e.g. force, angle, knife geometry) involved in knife attacks have been considered to design and construct a suitable device which allows these variables to be systematically controlled and varied. A device was designed and constructed from mild steel. This included a pivoting arm and instrumented knife holder. The arm has adjustable angle and weight so that knives can be operated at different calculated forces. A device was successfully constructed and the repeatability of incised knife trauma and its characteristics in skeletal tissues were investigated. A device which allows reproducible and controlled experiments with knife wounds will be advantageous to forensic investigations. In particular, in determining forces and types of weapons associated with particular wounds, identifying or eliminating suspected weapons and more accurately answering the common question: How much force would be required to cause that particular wound. This could help to characterise the perpetrator. The device can be altered to be used in the future to investigate trauma caused by other weapons. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Prefrontal left--dominant hemisphere--gamma and delta oscillators in general anaesthesia with volatile anaesthetics during open thoracic surgery.

    PubMed

    Saniova, Beata; Drobny, Michal; Drobna, Eva; Hamzik, Julian; Bakosova, Erika; Fischer, Martin

    2016-01-01

    The main objective was to indicate sufficient general anaesthesia (GA) inhibition for negative experience rejection in GA. We investigated the group of patients (n = 17, mean age 63.59 years, 9 male--65.78 years, 8 female - 61.13 years) during GA in open thorax surgery and analyzed EEG signal by power spectrum (pEEG) delta (DR), and gamma rhythms (GR). EEG was performed: OPO - the day before surgery and in surgery phases OP1-OP5 during GA. Particular GA phases: OP1 = after pre- medication, OP2 = surgery onset, OP3 = surgery with one-side lung ventilation, OP4 = end of surgery, both sides ventilation, OP5 = end of GA. pEEG registering in the left frontal region Fp1-A1 montage in 17 right handed persons. Mean DR power in OP2 phase is significantly higher than in phase OP5 and mean DR power in OP3 is higher than in OP5. One-lung ventilation did not change minimal alveolar concentration and gases should not accelerate decrease in mean DR power. Higher mean value of GR power in OPO than in OP3 was statistically significant. Mean GR power in OP3 is statistically significantly lower than in OP4 correlating with the same gases concentration in OP3 and OP4. Our results showed DR power decreased since OP2 till the end of GA it means inhibition represented by power DR fluently decreasing is sufficient for GA depth. GR power decay near the working memory could reduce conscious cognition and unpleasant explicit experience in GA.

  16. Knife-assisted snare resection: a novel technique for resection of scarred polyps in the colon.

    PubMed

    Chedgy, Fergus J Q; Bhattacharyya, Rupam; Kandiah, Kesavan; Longcroft-Wheaton, Gaius; Bhandari, Pradeep

    2016-03-01

    There have been significant advances in the management of complex colorectal polyps. Previous failed resection or polyp recurrence is associated with significant fibrosis, making endoscopic resection extremely challenging; the traditional approach to these lesions is surgery. The aim of this study was to evaluate the efficacy of a novel, knife-assisted snare resection (KAR) technique in the resection of scarred colonic polyps. This was a prospective cohort study of patients, in whom the KAR technique was used to resect scarred colonic polyps > 2  cm in size. Patients had previously undergone endoscopic mucosal resection (EMR) and developed recurrence, or EMR had been attempted but was aborted as a result of technical difficulty. A total of 42 patients underwent KAR of large (median 40  mm) scarred polyps. Surgery for benign disease was avoided in 38 of 41 patients (93 %). No life-threatening complications occurred. Recurrence was seen in six patients (16 %), five of whom underwent further endoscopic resection. The overall cure rate for KAR in complex scarred colonic polyps was 90 %. KAR of scarred colonic polyps by an expert endoscopist was an effective and safe technique with low recurrence rates. © Georg Thieme Verlag KG Stuttgart · New York.

  17. Primary Endoscopic Transnasal Transsphenoidal Surgery for Giant Pituitary Adenoma.

    PubMed

    Kuo, Chao-Hung; Yen, Yu-Shu; Wu, Jau-Ching; Chang, Peng-Yuan; Chang, Hsuan-Kan; Tu, Tsung-Hsi; Huang, Wen-Cheng; Cheng, Henrich

    2016-07-01

    Giant pituitary adenoma (>4 cm) remains challenging because the optimal surgical approach is uncertain. Consecutive patients with giant pituitary adenoma who underwent endoscopic transnasal transsphenoidal surgery (ETTS) as the first and primary treatment were retrospectively reviewed. Inclusion criteria were tumor diameter ≥4 cm in at least 1 direction, and tumor volume ≥10 cm(3). Exclusion criteria were follow-ups <2 years and diseases other than pituitary adenoma. All the clinical and radiologic outcomes were evaluated. A total of 38 patients, average age 50.8 years, were analyzed with a mean follow-up of 72.9 months. All patients underwent ETTS as the first and primary treatment, and 8 (21.1%) had complete resection without any evidence of recurrence at the latest follow-up. Overall, mean tumor volume decreased from 29.7 to 3.2 cm(3) after surgery. Residual and recurrent tumors (n = 30) were managed with 1 of the following: Gamma Knife radiosurgery (GKRS), reoperation (redo ETTS), both GKRS and ETTS, medication, conventional radiotherapy, or none. At last follow-up, most of the patients had favorable outcomes, including 8 (21.1%) who were cured and 29 (76.3%) who had a stable residual condition without progression. Only 1 (2.6%) had late recurrence at 66 months after GKRS. The overall progression-free rate was 97.4%, with few complications. In this series of giant pituitary adenoma, primary (ie, the first) ETTS yielded complete resection and cure in 21.1%. Along with adjuvant therapies, including GKRS, most patients (97.4%) were stable and free of disease progression. Therefore, primary ETTS appeared to be an effective surgical approach for giant pituitary adenoma. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. A novel device for endoscopic submucosal dissection, the Fork knife

    PubMed Central

    Kim, Hyun Gun; Cho, Joo Young; Bok, Gene Hyun; Cho, Won Young; Kim, Wan Jung; Hong, Su Jin; Ko, Bong Min; Kim, Jin Oh; Lee, Joon Seong; Lee, Moon Sung; Shim, Chan Sup

    2008-01-01

    AIM: To introduce and evaluate the efficacy and technical aspects of endoscopic submucosal dissection (ESD) using a novel device, the Fork knife. METHODS: From March 2004 to April 2008, ESD was performed on 265 gastric lesions using a Fork knife (Endo FS®) (group A) and on 72 gastric lesions using a Flexknife (group B) at a single tertiary referral center. We retrospectively compared the endoscopic characteristics of the tumors, pathological findings, and sizes of the resected specimens. We also compared the en bloc resection rate, complete resection rate, complications, and procedure time between the two groups. RESULTS: The mean size of the resected specimens was 4.27 ± 1.26 cm in group A and 4.29 ± 1.48 cm in group B. The en bloc resection rate was 95.8% (254/265 lesions) in group A and 93.1% (67/72) in group B. Complete ESD without tumor cell invasion of the resected margin was obtained in 81.1% (215/265) of group A and in 73.6% (53/72) of group B. The perforation rate was 0.8% (2/265) in group A and 1.4% (1/72) in group B. The mean procedure time was 59.63 ± 56.12 min in group A and 76.65 ± 70.75 min in group B (P < 0.05). CONCLUSION: The Fork knife (Endo FS®) is useful for clinical practice and has the advantage of reducing the procedure time. PMID:19034979

  19. The Shoemaker's Knife--An Approach of the Polya Type.

    ERIC Educational Resources Information Center

    Libeskind, Shlomo; Lott, Johnny W.

    1984-01-01

    Archimedes' shoemaker's knife problem is interesting in its own right and also allows the demonstration of heuristic teaching ideas and a different method of doing a routine construction. The focus in the article is on the thought processes involved and questions asked when attempting proofs with the problem. (MNS)

  20. A prototype small CdTe gamma camera for radioguided surgery and other imaging applications.

    PubMed

    Tsuchimochi, Makoto; Sakahara, Harumi; Hayama, Kazuhide; Funaki, Minoru; Ohno, Ryoichi; Shirahata, Takashi; Orskaug, Terje; Maehlum, Gunnar; Yoshioka, Koki; Nygard, Einar

    2003-12-01

    Gamma probes have been used for sentinel lymph node biopsy in melanoma and breast cancer. However, these probes can provide only radioactivity counts and variable pitch audio output based on the intensity of the detected radioactivity. We have developed a small semiconductor gamma camera (SSGC) that allows visualisation of the size, shape and location of the target tissues. This study is designed to characterise the performance of the SSGC for radioguided surgery of metastatic lesions and for other imaging applications amenable to the smaller format of this prototype imaging system. The detector head had 32 cadmium telluride semiconductor arrays with a total of 1,024 pixels, and with application-specific integrated circuits (ASICs) and a tungsten collimator. The entire assembly was encased in a lead housing measuring 152 mmx166 mmx65 mm. The effective visual field was 44.8 mmx44.8 mm. The energy resolution and imaging aspects were tested. Two spherical 5-mm- and 15-mm-diameter technetium-99m radioactive sources that had activities of 0.15 MBq and 100 MBq, respectively, were used to simulate a sentinel lymph node and an injection site. The relative detectability of these foci by the new detector and a conventional scintillation camera was studied. The prototype was also examined in a variety of clinical applications. Energy resolution [full-width at half-maximum (FWHM)] for a single element at the centre of the field of view was 4.2% at 140 keV (99mTc), and the mean energy resolution of the CdTe detector arrays was approximately 7.8%. The spatial resolution, represented by FWHM, had a mean value of 1.56 +/- 0.05 mm. Simulated node foci could be visualised clearly by the SSGC using a 15-s acquisition time. In preliminary clinical tests, the SSGC successfully imaged diseases in a variety of tissues, including salivary and thyroid glands, temporomandibular joints and sentinel lymph nodes. The SSGC has significant potential for diagnosing diseases and facilitating

  1. Long-term stability of the Leksell Gamma Knife{sup ®} Perfexion™ patient positioning system (PPS)

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

    Novotny, J., E-mail: josef.novotnyml@homolka.cz; Department of Medical Physics, Na Homolce Hospital, Prague 150 30; Institute of Biophysics and Informatics, First Faculty of Medicine, Charles University in Prague, Prague 120 00

    2014-03-15

    Purpose: To assess the long-term mechanical stability and accuracy of the patient positioning system (PPS) of the Leksell Gamma Knife{sup ®} Perfexion™ (LGK PFX). Methods: The mechanical stability of the PPS of the LGK PFX was evaluated using measurements obtained between September 2007 and June 2011. Three methods were employed to measure the deviation of the coincidence of the radiological focus point (RFP) and the PPS calibration center point (CCP). In the first method, the onsite diode test tool with single diode detector was used together with the 4 mm collimator on a daily basis. In the second method, amore » service diode test tool with three diode detectors was used biannually at the time of the routine preventive maintenance. The test performed with the service diode test tool measured the deviations for all three collimators 4, 8, and 16 mm and also for three different positions of the PPS. The third method employed the conventional film pin-prick method. This test was performed annually for the 4 mm collimator at the time of the routine annual QA. To estimate the effect of the patient weight on the performance of the PPS, the focus precision tests were also conducted with varying weights on the PPS using a set of lead bricks. Results: The average deviations measured from the 641 daily focus precision tests were 0.1 ± 0.1, 0.0 ± 0.0, and 0.0 ± 0.0 mm, respectively, for the 4 mm collimator in the X (left/right of the patient), Y (anterior/posterior of the patient), and Z (superior/inferior of the patient) directions. The average of the total radial deviations as measured during ten semiannual measurements with the service diode test tool were 0.070 ± 0.029, 0.060 ± 0.022, and 0.103 ± 0.028 mm, respectively for the central, long, and short diodes for the 4 mm collimator. Similarly, the average total radial deviations measured during the semiannual measurements for the 4, 8, and 16 mm collimators and using the central diode were 0.070 ± 0.029, 0

  2. Daniel K. Inouye Solar Telescope: computational fluid dynamic analyses and evaluation of the air knife model

    NASA Astrophysics Data System (ADS)

    McQuillen, Isaac; Phelps, LeEllen; Warner, Mark; Hubbard, Robert

    2016-08-01

    Implementation of an air curtain at the thermal boundary between conditioned and ambient spaces allows for observation over wavelength ranges not practical when using optical glass as a window. The air knife model of the Daniel K. Inouye Solar Telescope (DKIST) project, a 4-meter solar observatory that will be built on Haleakalā, Hawai'i, deploys such an air curtain while also supplying ventilation through the ceiling of the coudé laboratory. The findings of computational fluid dynamics (CFD) analysis and subsequent changes to the air knife model are presented. Major design constraints include adherence to the Interface Control Document (ICD), separation of ambient and conditioned air, unidirectional outflow into the coudé laboratory, integration of a deployable glass window, and maintenance and accessibility requirements. Optimized design of the air knife successfully holds full 12 Pa backpressure under temperature gradients of up to 20°C while maintaining unidirectional outflow. This is a significant improvement upon the .25 Pa pressure differential that the initial configuration, tested by Linden and Phelps, indicated the curtain could hold. CFD post- processing, developed by Vogiatzis, is validated against interferometry results of initial air knife seeing evaluation, performed by Hubbard and Schoening. This is done by developing a CFD simulation of the initial experiment and using Vogiatzis' method to calculate error introduced along the optical path. Seeing error, for both temperature differentials tested in the initial experiment, match well with seeing results obtained from the CFD analysis and thus validate the post-processing model. Application of this model to the realizable air knife assembly yields seeing errors that are well within the error budget under which the air knife interface falls, even with a temperature differential of 20°C between laboratory and ambient spaces. With ambient temperature set to 0°C and conditioned temperature set to 20

  3. Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour.

    PubMed

    Bleetman, A; Watson, C H; Horsfall, I; Champion, S M

    2003-12-01

    Stab attacks generate high loads, and to defeat them, armour needs to be of a certain thickness and stiffness. Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible. Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures. Phase 1: Two types of human slash behaviour were evident: a 'chop and drag' blow and a 'sweep motion' type of attack. 'Chop and drag' attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s(-1). The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s(-1). Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented. Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic

  4. Endoscopic submucosal dissection of early colorectal neoplasms with a monopolar scissor-type knife: short- to long-term outcomes.

    PubMed

    Kuwai, Toshio; Yamaguchi, Toshiki; Imagawa, Hiroki; Sumida, Yuki; Takasago, Takeshi; Miyasako, Yuki; Nishimura, Tomoyuki; Iio, Sumio; Yamaguchi, Atsushi; Kouno, Hirotaka; Kohno, Hiroshi; Ishaq, Sauid

    2017-09-01

    Background and study aims  Endoscopic submucosal dissection (ESD) for colorectal neoplasms remains challenging because of technical issues imposed by the complex anatomical features of the large intestine. We evaluated the feasibility, and the short- and long-term clinical outcomes of ESD for early colorectal neoplasms performed using the Stag-beetle Knife Jr. (SB Knife Jr.) Patients and methods  We retrospectively assessed 228 patients who underwent ESD for 247 colorectal lesions with the SB Knife Jr. Clinicopathological characteristics of the neoplasms, complications, and various short- and long-term outcomes were evaluated. Results  Mean tumor size was 34.3 mm and median procedure time was 76 minutes. The SB Knife Jr. achieved 98.4 % en bloc resection, 93.9 % complete resection, and 85.4 % curative resection. No perforations occurred during the procedure, and a delayed bleeding rate of 2.4 % was observed. Long-term outcomes were favorable with no distant recurrence, 1.1 % local recurrence, a 5-year overall survival rate of 94.1 % and 5-year tumor-specific survival rate of 98.6 % in patients with cancer. Conclusions  ESD using the SB Knife Jr. is technically efficient and safe in treating early colorectal neoplasms and is associated with favorable short- and long-term outcomes. © Georg Thieme Verlag KG Stuttgart · New York.

  5. A novel fully integrated handheld gamma camera

    NASA Astrophysics Data System (ADS)

    Massari, R.; Ucci, A.; Campisi, C.; Scopinaro, F.; Soluri, A.

    2016-10-01

    In this paper, we present an innovative, fully integrated handheld gamma camera, namely designed to gather in the same device the gamma ray detector with the display and the embedded computing system. The low power consumption allows the prototype to be battery operated. To be useful in radioguided surgery, an intraoperative gamma camera must be very easy to handle since it must be moved to find a suitable view. Consequently, we have developed the first prototype of a fully integrated, compact and lightweight gamma camera for radiopharmaceuticals fast imaging. The device can operate without cables across the sterile field, so it may be easily used in the operating theater for radioguided surgery. The prototype proposed consists of a Silicon Photomultiplier (SiPM) array coupled with a proprietary scintillation structure based on CsI(Tl) crystals. To read the SiPM output signals, we have developed a very low power readout electronics and a dedicated analog to digital conversion system. One of the most critical aspects we faced designing the prototype was the low power consumption, which is mandatory to develop a battery operated device. We have applied this detection device in the lymphoscintigraphy technique (sentinel lymph node mapping) comparing the results obtained with those of a commercial gamma camera (Philips SKYLight). The results obtained confirm a rapid response of the device and an adequate spatial resolution for the use in the scintigraphic imaging. This work confirms the feasibility of a small gamma camera with an integrated display. This device is designed for radioguided surgery and small organ imaging, but it could be easily combined into surgical navigation systems.

  6. Large early gastric cancers treated by endoscopic submucosal dissection with an insulation-tipped diathermic knife.

    PubMed

    Chang, Chun-Chao; Tiong, Cheng; Fang, Chia-Lang; Pan, Shiann; Liu, Jean-Dean; Lou, Horng-Yuan; Hsieh, Ching-Ruey; Chen, Sheng-Hsuan

    2007-03-01

    It is difficult to remove a large early gastric cancer (> or = 3 cm) in one-piece resection using conventional endoscopic mucosal resection. We tried to use an insulation-tipped (IT) diathermic knife to dissect these lesions. IT-endoscopic submucosal dissection (ESD) was performed in four aging patients with gastric malignancy. All lesions could be removed in one-piece resection by IT-ESD, although three of them exhibited remarkable fibrosis and ulceration. Three cases experienced curative treatment with IT-ESD after the pathologic evaluation, but it was not curative in one case because the pathology showed angiolymphatic invasion. This patient refused additional surgery in consideration of existing major systemic diseases. At 3 months to 1 year of follow-up, endoscopy showed no evidence of residual cancer. IT-ESD is effective in the treatment of large early gastric cancer and is an alternative treatment for early gastric cancer patients who are at risk for major operation.

  7. 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

  8. The Critical Compression Load for a Universal Testing Machine When the Specimen Is Loaded Through Knife Edges

    NASA Technical Reports Server (NTRS)

    Lundquist, Eugene E; Schwartz, Edward B

    1942-01-01

    The results of a theoretical and experimental investigation to determine the critical compression load for a universal testing machine are presented for specimens loaded through knife edges. The critical load for the testing machine is the load at which one of the loading heads becomes laterally instable in relation to the other. For very short specimens the critical load was found to be less than the rated capacity given by the manufacturer for the machine. A load-length diagram is proposed for defining the safe limits of the test region for the machine. Although this report is particularly concerned with a universal testing machine of a certain type, the basic theory which led to the derivation of the general equation for the critical load, P (sub cr) = alpha L can be applied to any testing machine operated in compression where the specimen is loaded through knife edges. In this equation, L is the length of the specimen between knife edges and alpha is the force necessary to displace the upper end of the specimen unit horizontal distance relative to the lower end of the specimen in a direction normal to the knife edges through which the specimen is loaded.

  9. "Fist, Stick, Knife, Gun": Getting Real in Upward Bound.

    ERIC Educational Resources Information Center

    Pace, Barbara G.; Adkins, Theresa A.

    2002-01-01

    Describes how a teacher found literature for Upward Bound students. Presents Geoffrey Canada's "Fist, Stick, Knife, Gun: A Personal History of Violence in America" as a nonfiction work to provide clarity and connections that might not have been available in a fictional work, yet it had elements of literary fiction that made the text…

  10. Atom-optics knife-edge: Measuring sub-nanokelvin momentum distributions

    NASA Astrophysics Data System (ADS)

    Ramos, Ramon; Spierings, David; Steinberg, Aephraim

    2017-04-01

    Temperatures below 1 nanokelvin have been achieved in the recent years, enabling new classes of experiments which benefit from the resulting long coherence times. This achievement comes hand in hand with the challenge of measuring such low temperatures. By employing the equivalent of a knife-edge measurement for matter-waves, we have been able to characterize ultra-low momentum widths. We measured a momentum width corresponding to an effective temperature of 900 +/- 200 pK, only limited by our cooling performance. We show that this technique compares favourably with more traditional methods, which would require expansion times of 100's of ms or frequency stability of 10's of Hz. Finally, we show that the effective knife-edge, created by a potential barrier, begins to become ''blunt'' due to tunneling for thin barriers, and we obtain quantitative agreement with a theoretical model. This method is a useful tool for atomic interferometry and other areas in ultracold atoms where a robust and precise technique for characterizing the momentum distribution is required.

  11. The effects of bariatric surgery: will understanding its mechanism render the knife unnecessary?

    PubMed

    Browning, Kirsteen N; Hajnal, Andras

    2014-01-01

    The incidence of obesity is increasing worldwide at a dramatic rate, accompanied by an associated increase in comorbid conditions. Bariatric surgery is the most effective treatment for morbid obesity with Roux-en-Y gastric bypass being the most commonly performed procedure, yet the underlying mechanisms by which it induces a wide-array of beneficial effects remains obscure. From basic science as well as clinical standpoints, there are several areas of current interest that warrant continued investigation. Several major focus areas have also emerged in current research that may guide future efforts in this field, particularly with regards to using novel, non-surgical approaches to mimic the success of bariatric surgery while minimizing its adverse side effects.

  12. Does the stoichiometric carbon:phosphorus knife edge apply for predaceous copepods?

    PubMed

    Laspoumaderes, Cecilia; Modenutti, Beatriz; Elser, James J; Balseiro, Esteban

    2015-06-01

    Recent work has indicated that stoichiometric food quality in terms of the carbon:phosphorus (C:P) ratio affects consumers whether the imbalance involves a deficit or an excess of nutrients; hence, organisms exist on a "stoichiometric knife edge". While previous studies have focused primarily on autotroph-herbivore trophic transfer, nutritional imbalances may also affect the interactions between species at higher trophic levels. Since the foods of carnivores are normally stoichiometrically similar to the body compositions of those carnivores, they may be more severely affected than herbivores if imbalances become pronounced. We analysed the response of the predatory copepod Parabroteas sarsi to monospecific diet treatments consisting of high and low C:P prey items. These dietary treatments strongly affected the predator's elemental composition and growth, although prey selection, excretion, egestion, and respiration rates were not affected. We suggest that, due to their low threshold elemental ratio and a narrow C:P stoichiometric knife edge, these predators are highly vulnerable to stoichiometric imbalances, whether an excess or a deficit of nutrients is involved. Our results demonstrating this high sensitivity to prey C:P ratio show that the stoichiometric knife edge may apply to not only herbivores but also higher trophic levels. Thus, predators such as P. sarsi, with a much narrower range of food quality, may also be strongly affected by fluctuations in the quality of their prey, with negative consequences for their secondary production.

  13. Cervical spondylodiscitis with epidural abscess after knife stab wounds to the neck: A case report.

    PubMed

    Voelker, Anna; von der Hoeh, Nicolas H; Gulow, Jens; Heyde, Christoph-Eckhard

    2015-08-01

    Cervical spondylodiscitis is usually caused by pyogenic infections, associated with retropharyngeal abscesses, or due to the swallowing of foreign bodies. No cases of cervical spondylodiscitis caused by a penetrating neck injury have been published in the literature. We describe a case of cervical spondylodiscitis after multiple knife stab wounds to the lateral soft tissue of the neck. Case report and review of the literature. A 54-year-old patient was brought to our clinic with destructive spondylodiscitis C3/4 with paravertebral and epidural abscesses. He had been involved in a fight and had suffered multiple stab wounds to his neck with a knife 1 month prior. The initial CT scan had revealed one deeper wound canal behind the sternocleidomastoid muscle on the left side without any injury to the vessels. The wound was cleaned and an antibiotic therapy with cefuroxime was given for 1 week. After an uneventful and complete healing of the wound the patient developed severe neck pain. Inflammatory laboratory parameters were elevated, and a MRI of the neck revealed a distinct spondylodiscitis C3/4 with paravertebral and epidural abscess formations. Surgery was performed and included debridement, abscess drainage, decompression of the spinal canal, fusion of the C3/4 segment using an autologous iliac crest bone graft and a plate osteosynthesis. A course of calculated antibiotic therapy was administered for 8 weeks. Normal laboratory parameters and no radiological signs of an ongoing inflammatory process were observed during follow-up examinations. The C3/4 segment was consolidated. Stab wound injuries to the neck not only bear the risk of injuries to the nerves, vessels and organs of the neck but also increase the risk of developing secondary spondylodiscitis. Specifically, cervical spondylodiscitis can result in distinct neurological symptoms, and surgical intervention should be performed in a timely manner. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. SU-F-T-649: Dosimetric Evaluation of Non-Coplanar Arc Therapy Using a Novel Rotating Gamma Ray System

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

    Eldib, A; Chibani, O; Jin, L

    2016-06-15

    Purpose: Stereotactic intra and extra-cranial body radiation therapy has evolved with advances in treatment accuracy, effective radiation dose, and parameters necessary to maximize machine capabilities. Novel gamma systems with a ring type gantry were developed having the ability to perform oblique arcs. The aim of this study is to explore the dosimetric advantages of this new system. Methods: The rotating Gamma system is named CybeRay (Cyber Medical Corp., Xian, China). It 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. Treatment plansmore » were generated utilizing our in-house Monte Carlo treatment planning system. A cylindrical phantom was modeled with 2mm voxel size. Dose inside the cylindrical phantom was calculated for coplanar and non-coplanar arcs. Dosimetric differences between CybeRay cobalt beams and CyberKnife 6MV beams were compared in a lung phantom and for previously treated SBRT patients. Results: The full width at half maxima of cross profiles in the S-I direction for the coplanar setup matched the cone sizes, while for the non-coplanar setup, FWHM was larger by 2mm for a 10mm cone and about 5mm for larger cones. In the coronal and sagittal view, coplanar beams showed elliptical shaped isodose lines, while non-coplanar beams showed circular isodose lines. Thus proper selection of the oblique angle and cone size can aid optimal dose matching to the target volume. Comparing a single 5mm cone from CybeRay to that from CyberKnife showed similar penumbra in a lung phantom but CybeRay had significant lower doses beyond lung tissues. Comparable treatment plans were obtained with CybeRay as that from CyberKnife.ConclusionThe noncoplanar multiple source arrangement of CybeRay will be of great clinical benefits for stereotactic intra and extra-cranial radiation therapy.« less

  15. Comparison of conventional versus Hybrid knife peroral endoscopic myotomy methods for esophageal achalasia: a case-control study.

    PubMed

    Tang, Xiaowei; Gong, Wei; Deng, Zhiliang; Zhou, Jieqiong; Ren, Yutang; Zhang, Qiang; Chen, Zhenyu; Jiang, Bo

    2016-01-01

    Peroral endoscopic myotomy (POEM) has been developed to treat achalasia as a novel less invasive modality. We aimed to compare the efficacy and safety of conventional knife versus Hybrid knife (HK) during POEM procedure. Between June 2012 and July 2014, 31 patients underwent POEM using HK in our department (HK group), and 36 patients underwent POEM using conventional method (injection needle and triangular tip [TT] knife, TT group). Procedure-related parameters, symptom relief, adverse events were compared between two groups. There were no significant differences in the age, sex and other baseline characteristics between the two groups. The mean procedural time was significantly shorter in HK group than TT group (53.0 ± 17.2 vs. 67.6 ± 28.4 min, p = 0.015). The mean frequency of devices exchange was 4.7 ± 1.7 in HK group and 10.9 ± 1.8 in TT group (p = 0.000). No serious adverse events occurred postoperatively in both groups. At one-year follow-up, a total of 94% treatment success was achieved in all patients (93.5% in HK group and 94.4% in TT group, p = 0.877). HK in POEM can shorten the procedural time, and achieve similar treatment success compared to conventional TT knife.

  16. Vision correction via multi-layer pattern corneal surgery

    NASA Astrophysics Data System (ADS)

    Sun, Han-Yin; Wang, Hsiang-Chen; Yang, Shun-Fa

    2013-07-01

    With the rapid development of vision correction techniques, increasing numbers of people have undergone laser vision corrective surgery in recent years. The use of a laser scalpel instead of a traditional surgical knife reduces the size of the wound and quickens recovery after surgery. The primary objective of this article is to examine corneal surgery for vision correction via multi-layer swim-ring-shaped wave circles of the technique through optical simulations with the use of Monte-Carlo ray tracing method. Presbyopia stems from the loss of flexibility of crystalline lens due to aging of the eyeball. Diopter adjustment of a normal crystalline lens could reach 5 D; in the case of presbyopia, the adjustment was approximately 1 D, which made patients unable to see objects clearly in near distance. Corneal laser surgery with multi-layer swim-ring-shaped wave circles was performed, which ablated multiple circles on the cornea to improve flexibility of the crystalline lens. Simulation results showed that the ability of the crystalline lens to adjust increased tremendously from 1 D to 4 D. The method was also used to compare the images displayed on the retina before and after the treatment. The results clearly indicated a significant improvement in presbyopia symptoms with the use of this technique.

  17. Comparison of effects on voice of diode laser and cold knife microlaryngology techniques for vocal fold polyps.

    PubMed

    Karasu, Mehmet Fatih; Gundogdu, Ramazan; Cagli, Sedat; Aydin, Mesut; Arli, Turan; Aydemir, Samet; Yuce, Imdat

    2014-05-01

    To compare the effects on voice of endolaryngeal microsurgery (EMS) with cold instruments and a new method, "diode laser," for vocal fold polyps. Fifty-one patients with vocal fold polyps suffering from dysphonia who were treated in the Erciyes University Department of Otolaryngology were included in the study. Voice analysis was performed in a soundproof room, holding the microphone 15 cm away from the patients' mouth and by recording a sustained [a] vowel for at least 10 seconds. Fundamental frequency (F0), Jitter, Shimmer, and noise-to-harmonic ratio (NHR) parameters were evaluated in terms of vocal analysis. All patients were asked for to fill in a questionnaire, after being informed about the voice handicap index (VHI). EMS was performed with a diode laser and cold knife on 26 and 25 patients, respectively. Patient follow-up was performed 8 weeks after surgery. Changes in F0, Jitter, Shimmer, and NHR values were measured and recorded. VHI was also completed and reassessed. There was a significant difference in each technique's VHI score between the preoperative and postoperative questionnaire (P < 0.001). Postoperatively, there was no significant difference in VHI scores between two groups (P > 0.05). There was a significant difference in voice analysis values measured preoperatively and at the postoperative controls for both groups (P < 0.05). Postoperatively, there was no significant difference in voice analysis values between two groups (P > 0.05). In the treatment of vocal polyps, EMS with both diode laser and traditional cold knife is effective. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  18. A quiet harvest: linkage between ritual, seed selection and the historical use of the finger-bladed knife as a traditional plant breeding tool in Ifugao, Philippines.

    PubMed

    Murphy, Kevin M

    2017-01-13

    The transverse harvest knife, also commonly called the finger or finger-bladed knife, has been utilized by rice farmers in southeast Asia for many centuries. The finger knife persisted in many traditional cultures long after the introduction of the sickle, a tool which provided farmers with the means to execute a much faster harvest. Several theories in interpretative archaeology have attempted to account for this rejection of more modern technological innovations. These theories, which include community-based social organization ideas and practical reasons for the continued use of the finger knife, are presented in this paper. Here I suggest an alternate theory based on a re-interpretation of existing research and fusion of existing theories: the primary reason for the historical and continued use of the finger knife is for seed selection through a centuries old tradition of plant breeding. Though I accept the accuracy of the practical and community-based, socio-cultural reasons for the use of the finger knife put forth by other authors, I suggest that seed selection and genetic improvement was the driving factor in the use of the finger knife. Indeed, intricate planting and harvesting rituals, which both ensured and encouraged varietal conservation and improvement co-evolved with the use of the finger knife as the primary harvest tool due to its unique ability to aid the farmer in the art and science of seed selection. When combined with previous ideas, this interpretative theory, based on the connection between ethnoagronomy and material culture, may provide a more complete picture of the story around the persistence of the finger knife in traditional rice-growing cultures in southeast Asia. I focus my theory on the terrace-building Ifugao people in the mountainous Cordillera region of northcentral Philippines; however, to put the use of the finger into a wider regional context, I draw from examples of the use of the finger knife in other traditional cultures

  19. The "Knife-Cut Sign" Revisited: A Distinctive Presentation of Linear Erosive Herpes Simplex Virus Infection in Immunocompromised Patients.

    PubMed

    Cohen, Philip R

    2015-10-01

    The "knife-cut sign" is a distinctive presentation of linear erosive herpes simplex virus infection in immunocompromised patients. To describe a man whose herpes simplex virus infection-related skin lesions demonstrated the "knife-cut sign" and to review the characteristics of reported immunosuppressed individuals with "knife-cut" cutaneous herpes simplex virus lesions. A man with multiple myeloma and post-stem cell transplant cutaneous graft-versus-host disease managed with systemic prednisone and sirolimus developed disseminated cutaneous herpes simplex virus infection with virus-associated linear ulcers of the inguinal folds and the area between his ear and scalp; the lesions at both sites had a distinctive "knife-cut" appearance. Using the PubMed database, an extensive literature search was performed on herpes simplex virus, immunocompromised patient, and "knife-cut sign". Herpes simplex virus infection-associated skin lesions that demonstrate the "knife-cut sign" present in patients who are immunosuppressed secondary to either an underlying medical condition or a systemic therapy or both. The distinctive virus-related cutaneous lesions appear as linear ulcers and fissures in intertriginous areas, such as the folds in the inguinal area, the vulva, and the abdomen; in addition, other sites include beneath the breast, within the gluteal cleft, and the area between the ear and the scalp. Not only herpes simplex virus-2, but also herpes simplex virus-1 has been observed as the causative viral serotype; indeed, herpes simplex virus-1 has been associated with genital and inframammary lesions in addition to those above the neck. Direct fluorescent antibody testing is a rapid method for confirming the clinically suspected viral infection; however, since false-negative direct fluorescent antibody testing occurred in some of the patients, it may be prudent to also perform viral cultures and possibly lesional skin biopsies to establish the diagnosis. The herpes simplex

  20. Flex-rigid pleuroscopic biopsy with the SB knife Jr is a novel technique for diagnosis of malignant or benign fibrothorax.

    PubMed

    Wang, Xiao-Bo; Yin, Yan; Miao, Yuan; Eberhardt, Ralf; Hou, Gang; Herth, Felix J; Kang, Jian

    2016-11-01

    Diagnosing pleural effusion is challenging, especially in patients with malignant or benign fibrothorax, which is difficult to sample using standard flexible forceps (SFF) via flex-rigid pleuroscopy. An adequate sample is crucial for the differential diagnosis of malignant fibrothorax (malignant pleural mesothelioma, metastatic lung carcinoma, etc.) from benign fibrothorax (benign asbestos pleural disease, tuberculous pleuritis, etc.). Novel biopsy techniques are required in flex-rigid pleuroscopy to improve the sample size and quality. The SB knife Jr, which is a scissor forceps that uses a mono-pole high frequency, was developed to allow convenient and accurate resection of larger lesions during endoscopic dissection (ESD). Herein, we report two patients with fibrothorax who underwent a pleural biopsy using an SB knife Jr to investigate the potential use of this tool in flex-rigid pleuroscopy when pleural lesions are difficult to biopsy via SFF. The biopsies were successful, with sufficient size and quality for definitive diagnosis. We also successfully performed adhesiolysis with the SB knife Jr in one case, and adequate biopsies were conducted. No complications were observed. Electrosurgical biopsy with the SB knife Jr during flex-rigid pleuroscopy allowed us to obtain adequate samples for the diagnosis of malignant versus benign fibrothorax, which is usually not possible with SFF. The SB knife Jr also demonstrated a potential use for pleuropulmonary adhesions.

  1. Single‐fraction spine SBRT end‐to‐end testing on TomoTherapy, Vero, TrueBeam, and CyberKnife treatment platforms using a novel anthropomorphic phantom

    PubMed Central

    Kaufman, Isaac; Powell, Rachel; Pandya, Shalini; Somnay, Archana; Bossenberger, Todd; Ramirez, Ezequiel; Reynolds, Robert; Solberg, Timothy; Burmeister, Jay

    2015-01-01

    , respectively. Film measurements for the lumbar targets resulted in average global gamma index passing rates of 100% at 3%/3 mm, 96.9% at 2%/2 mm, and 61.8% at 1%/1 mm, with a 10% minimum threshold for all plans on all platforms. Local gamma analysis was also performed with similar results. While gamma passing rates were consistently accurate across all platforms through 2%/2 mm, treatment beam‐on delivery times varied greatly between each platform with TrueBeam FFF being shortest, averaging 4.4 min, TrueBeam using flattened beam at 9.5 min, TomoTherapy at 30.5 min, Vero at 19 min, and CyberKnife at 46.0 min. In spite of the complexity of the representative targets and their proximity to the spinal cord, all treatment platforms were able to create plans meeting all RTOG 0631 dose constraints and produced exceptional agreement between calculated and measured doses. However, there were differences in the plan characteristics and significant differences in the beam‐on delivery time between platforms. Thus, clinical judgment is required for each particular case to determine most appropriate treatment planning/delivery platform. PACS number: 87.53.Ly PMID:25679169

  2. CyberArc: a non-coplanar-arc optimization algorithm for CyberKnife

    NASA Astrophysics Data System (ADS)

    Kearney, Vasant; Cheung, Joey P.; McGuinness, Christopher; Solberg, Timothy D.

    2017-07-01

    The goal of this study is to demonstrate the feasibility of a novel non-coplanar-arc optimization algorithm (CyberArc). This method aims to reduce the delivery time of conventional CyberKnife treatments by allowing for continuous beam delivery. CyberArc uses a 4 step optimization strategy, in which nodes, beams, and collimator sizes are determined, source trajectories are calculated, intermediate radiation models are generated, and final monitor units are calculated, for the continuous radiation source model. The dosimetric results as well as the time reduction factors for CyberArc are presented for 7 prostate and 2 brain cases. The dosimetric quality of the CyberArc plans are evaluated using conformity index, heterogeneity index, local confined normalized-mutual-information, and various clinically relevant dosimetric parameters. The results indicate that the CyberArc algorithm dramatically reduces the treatment time of CyberKnife plans while simultaneously preserving the dosimetric quality of the original plans.

  3. CyberArc: a non-coplanar-arc optimization algorithm for CyberKnife.

    PubMed

    Kearney, Vasant; Cheung, Joey P; McGuinness, Christopher; Solberg, Timothy D

    2017-06-26

    The goal of this study is to demonstrate the feasibility of a novel non-coplanar-arc optimization algorithm (CyberArc). This method aims to reduce the delivery time of conventional CyberKnife treatments by allowing for continuous beam delivery. CyberArc uses a 4 step optimization strategy, in which nodes, beams, and collimator sizes are determined, source trajectories are calculated, intermediate radiation models are generated, and final monitor units are calculated, for the continuous radiation source model. The dosimetric results as well as the time reduction factors for CyberArc are presented for 7 prostate and 2 brain cases. The dosimetric quality of the CyberArc plans are evaluated using conformity index, heterogeneity index, local confined normalized-mutual-information, and various clinically relevant dosimetric parameters. The results indicate that the CyberArc algorithm dramatically reduces the treatment time of CyberKnife plans while simultaneously preserving the dosimetric quality of the original plans.

  4. 18. DETAIL OF COMBINATION HANDWASH SINK/KNIFE STERILIZER ON SPLITTERS' PLATFORM; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. DETAIL OF COMBINATION HANDWASH SINK/KNIFE STERILIZER ON SPLITTERS' PLATFORM; KNIVES AND CLEAVERS WERE CLEANED FREQUENTLY BY DIPPING THEM INTO STEAM-HEATED WATER IN THE RECTANGULAR TANK; NOTE FOOT-OPERATED FAUCETS - Rath Packing Company, Beef Killing Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA

  5. 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

  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. 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.

  8. Prompt gamma imaging of proton pencil beams at clinical dose rate

    NASA Astrophysics Data System (ADS)

    Perali, I.; Celani, A.; Bombelli, L.; Fiorini, C.; Camera, F.; Clementel, E.; Henrotin, S.; Janssens, G.; Prieels, D.; Roellinghoff, F.; Smeets, J.; Stichelbaut, F.; Vander Stappen, F.

    2014-10-01

    In this work, we present experimental results of a prompt gamma camera for real-time proton beam range verification. The detection system features a pixelated Cerium doped lutetium based scintillation crystal, coupled to Silicon PhotoMultiplier arrays, read out by dedicated electronics. The prompt gamma camera uses a knife-edge slit collimator to produce a 1D projection of the beam path in the target on the scintillation detector. We designed the detector to provide high counting statistics and high photo-detection efficiency for prompt gamma rays of several MeV. The slit design favours the counting statistics and could be advantageous in terms of simplicity, reduced cost and limited footprint. We present the description of the realized gamma camera, as well as the results of the characterization of the camera itself in terms of imaging performance. We also present the results of experiments in which a polymethyl methacrylate phantom was irradiated with proton pencil beams in a proton therapy center. A tungsten slit collimator was used and prompt gamma rays were acquired in the 3-6 MeV energy range. The acquisitions were performed with the beam operated at 100 MeV, 160 MeV and 230 MeV, with beam currents at the nozzle exit of several nA. Measured prompt gamma profiles are consistent with the simulations and we reached a precision (2σ) in shift retrieval of 4 mm with 0.5 × 108, 1.4 × 108 and 3.4 × 108 protons at 100, 160 and 230 MeV, respectively. We conclude that the acquisition of prompt gamma profiles for in vivo range verification of proton beam with the developed gamma camera and a slit collimator is feasible in clinical conditions. The compact design of the camera allows its integration in a proton therapy treatment room and further studies will be undertaken to validate the use of this detection system during treatment of real patients.

  9. Endoscopic submucosal dissection for early esophageal neoplasms using the stag beetle knife.

    PubMed

    Kuwai, Toshio; Yamaguchi, Toshiki; Imagawa, Hiroki; Miura, Ryoichi; Sumida, Yuki; Takasago, Takeshi; Miyasako, Yuki; Nishimura, Tomoyuki; Iio, Sumio; Yamaguchi, Atsushi; Kouno, Hirotaka; Kohno, Hiroshi; Ishaq, Sauid

    2018-04-21

    To determine short- and long-term outcomes of endoscopic submucosal dissection (ESD) using the stag beetle (SB) knife, a scissor-shaped device. Seventy consecutive patients with 96 early esophageal neoplasms, who underwent ESD using a SB knife at Kure Medical Center and Chugoku Cancer Center, Japan, between April 2010 and August 2016, were retrospectively evaluated. Clinicopathological characteristics of lesions and procedural adverse events were assessed. Therapeutic success was evaluated on the basis of en bloc , histologically complete, and curative or non-curative resection rates. Overall and tumor-specific survival, local or distant recurrence, and 3- and 5-year cumulative overall metachronous cancer rates were also assessed. Eligible patients had dysplasia/intraepithelial neoplasia (22%) or early cancers (squamous cell carcinoma, 78%). The median procedural time was 60 min and on average, the lesions measured 24 mm in diameter, yielding 33-mm tissue defects. The en bloc resection rate was 100%, with 95% and 81% of dissections deemed histologically complete and curative, respectively. All procedures were completed without accidental incisions/perforations or delayed bleeding. During follow-up (mean, 35 ± 23 mo), no local recurrences or metastases were observed. The 3- and 5-year survival rates were 83% and 70%, respectively, with corresponding rates of 85% and 75% for curative resections and 74% and 49% for non-curative resections. The 3- and 5-year cumulative rates of metachronous cancer in the patients with curative resections were 14% and 26%, respectively. ESD procedures using the SB knife are feasible, safe, and effective for treating early esophageal neoplasms, yielding favorable short- and long-term outcomes.

  10. 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.

  11. 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.

  12. Prompt Gamma Imaging for In Vivo Range Verification of Pencil Beam Scanning Proton Therapy.

    PubMed

    Xie, Yunhe; Bentefour, El Hassane; Janssens, Guillaume; Smeets, Julien; Vander Stappen, François; Hotoiu, Lucian; Yin, Lingshu; Dolney, Derek; Avery, Stephen; O'Grady, Fionnbarr; Prieels, Damien; McDonough, James; Solberg, Timothy D; Lustig, Robert A; Lin, Alexander; Teo, Boon-Keng K

    2017-09-01

    To report the first clinical results and value assessment of prompt gamma imaging for in vivo proton range verification in pencil beam scanning mode. A stand-alone, trolley-mounted, prototype prompt gamma camera utilizing a knife-edge slit collimator design was used to record the prompt gamma signal emitted along the proton tracks during delivery of proton therapy for a brain cancer patient. The recorded prompt gamma depth detection profiles of individual pencil beam spots were compared with the expected profiles simulated from the treatment plan. In 6 treatment fractions recorded over 3 weeks, the mean (± standard deviation) range shifts aggregated over all spots in 9 energy layers were -0.8 ± 1.3 mm for the lateral field, 1.7 ± 0.7 mm for the right-superior-oblique field, and -0.4 ± 0.9 mm for the vertex field. This study demonstrates the feasibility and illustrates the distinctive benefits of prompt gamma imaging in pencil beam scanning treatment mode. Accuracy in range verification was found in this first clinical case to be better than the range uncertainty margin applied in the treatment plan. These first results lay the foundation for additional work toward tighter integration of the system for in vivo proton range verification and quantification of range uncertainties. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Ribbons of semithin sections: an advanced method with a new type of diamond knife.

    PubMed

    Blumer, Michael J F; Gahleitner, P; Narzt, T; Handl, C; Ruthensteiner, B

    2002-10-15

    Complete series of semithin sections are imperative for 3-D reconstruction, but with traditional microtomy techniques it is difficult and time-consuming to trace stained and labeled structures. In the present study we introduce a method for making and collecting ribbons of semithin sections with a new, commercial available diamond knife (histo-jumbo-diamond knife, Diatome AG, Biel, Switzerland). The special feature of the diamond knife is the large water bath (boat) into which a glass slide can be dipped. The method has distinct advantages and the handling is simple. The resin block is trimmed into a truncated pyramid. Contact glue is applied to the leading face of the pyramid, which makes sections stick together to form a ribbon. Following sectioning, the ribbons are mounted onto glass slides and aligned in parallel. Stretching out and drying the ribbons on a hot plate is the final step of the method. Major advantages of this method are the perfect alignment of sections with identical orientation of structures, the completeness of series, and the significant saving of time. This facilitates tracing of stained and labeled structures, yielding quick 3-D reconstruction. Semithin sections can be cut from 0.5 to 2 micro m and several ribbons can be mounted side by side onto the slide. Two examples are presented to illustrate the advantages of the method.

  14. Long-term Auditory Symptoms in Patients With Sporadic Vestibular Schwannoma: An International Cross-Sectional Study.

    PubMed

    Tveiten, Oystein Vesterli; Carlson, Matthew L; Goplen, Frederik; Vassbotn, Flemming; Link, Michael J; Lund-Johansen, Morten

    2015-08-01

    There are limited data on the long-term auditory symptoms in patients with sporadic small- and medium-sized vestibular schwannoma (VS). The initial treatment strategy for VS is controversial. To characterize auditory symptoms in a large cohort of patients with VS. Patients with ≤3 cm VS who underwent primary microsurgery, gamma knife surgery, or observation between 1998 and 2008 at 2 independent hospitals were identified. Clinical data were extracted from existing VS databases. At a mean time of 7.7 years after initial treatment, patients were surveyed via mail with the use of the Hearing Handicap Inventory for Adults (HHIA) and the Tinnitus Handicap Inventory. The response rate was 79%; a total of 539 respondents were analyzed. Overall, the hearing prognosis was poor, because more than 75% of all patients had nonserviceable hearing at the last clinical follow-up. Good baseline hearing proved to be a strong predictor for maintained serviceable hearing. Treatment modality was independently associated with both audiometric outcome and HHIA results. Active treatment with microsurgery or gamma knife surgery did not appear to be protective, because patients who were observed had the greatest probability of durable hearing. Patients in the surgical series had the greatest hearing loss. Tinnitus Handicap Inventory results were less predictable. The only predictors of tinnitus handicap were age and HHIA score. The overall prognosis for hearing in sporadic VS is poor regardless of treatment strategy. Treatment modality was an independent predictor of hearing status; observation was associated with the highest rate of hearing preservation. .

  15. Knife River: Early Village Life on the Plains. Teaching with Historic Places.

    ERIC Educational Resources Information Center

    Metcalf, Fay

    This document, from the lesson plan series, "Teaching with Historic Places," examines the Native Americans who lived on the plains along the Knife River in what is now North Dakota. Following an introductory section, the document sets out student objectives, teaching activities, readings, and illustrations. The teaching activity…

  16. [Randomized controlled trials of needle knife therapy combined with rotation traction manipulation for the treatment of cervical spondylotic radiculopathy].

    PubMed

    Zhou, Zhong-Liang; Su, Guo-Hong; Zheng, Bao-Zhu; Zuo, Yu-Zhu; Wei, Fu-Liang

    2016-09-25

    To compare the therapeutic effects between needle knife therapy combined with rotation traction manipulation and rotation traction manipulation for the treatment of cervical spondylotic radiculopathy. From November 2013 to June 2015, 80 patients with cervical spondylotic radiculopathy meeting the inclusion criteria were divided into two groups randomly:the control group in which 39 patients were treated with rotation traction manipulation, and the treatment group in which 41 patients were treated with needle knife combined with rotation traction manipulation. The patients in the control group were treated once dayly for 2 weeks, which was 1 course. The patients in the treatment group were treated with needle knife firstly once a week for 2 weeks, which was 1 course;then were treated with the same methods as the patients in the control group. The symptoms, signs score and the therapeutic effects of the two groups before and after treatment were observed. After treatment, symptoms and signs scores declined in both groups( P <0.05). The results of the treatment group were better than effects in the control group( P <0.05). In the treatment group, 19 patients got an excellent result, 16 good, 5 fair and 1 bad;while in the control group, 10 patients got an excellent result, 10 good, 16 fair and 3 bad;the results of the treatment group were better than the results of the control group( P <0.01). Needle knife combined with rotation traction manipulation is an effective method for the treatment of cervical spondylotic radiculopathy, which is better than using manipulation method simply. Needle knife therapy has follow advantages:improving local blood circulation, reducing local content of pain substance, increasing production of substances resisting pain, opening channels and collaterals, and make body reaching new static and dynamic balance on the new foundation.

  17. SU-F-T-485: Independent Remote Audits for TG51 NonCompliant Photon Beams Performed by the IROC Houston QA Center

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

    Alvarez, P; Molineu, A; Lowenstein, J

    Purpose: IROC-H conducts external audits for output check verification of photon and electron beams. Many of these beams can meet the geometric requirements of the TG 51 calibration protocol. For those photon beams that are non TG 51 compliant like Elekta GammaKnife, Accuray CyberKnife and TomoTherapy, IROC-H has specific audit tools to monitor the reference calibration. Methods: IROC-H used its TLD and OSLD remote monitoring systems to verify the output of machines with TG 51 non compliant beams. Acrylic OSLD miniphantoms are used for the CyberKnife. Special TLD phantoms are used for TomoTherapy and GammaKnife machines to accommodate the specificmore » geometry of each machine. These remote audit tools are sent to institutions to be irradiated and returned to IROC-H for analysis. Results: The average IROC-H/institution ratios for 480 GammaKnife, 660 CyberKnife and 907 rotational TomoTherapy beams are 1.000±0.021, 1.008±0.019, 0.974±0.023, respectively. In the particular case of TomoTherapy, the overall ratio is 0.977±0.022 for HD units. The standard deviations of all results are consistent with values determined for TG 51 compliant photon beams. These ratios have shown some changes compared to values presented in 2008. The GammaKnife results were corrected by an experimentally determined scatter factor of 1.025 in 2013. The TomoTherapy helical beam results are now from a rotational beam whereas in 2008 the results were from a static beam. The decision to change modality was based on recommendations from the users. Conclusion: External audits of beam outputs is a valuable tool to confirm the calibrations of photon beams regardless of whether the machine is TG 51 or TG 51 non compliant. The difference found for TomoTherapy units is under investigation. This investigation was supported by IROC grant CA180803 awarded by the NCI.« less

  18. [Stiletto needle and needle-knife for influence of gravity index in treating knee osteoarthritis].

    PubMed

    Gu, Li-Jun; Zhang, Bin; Li, Wen-Hua; Tang, Yan; Dong, Fu-Hui

    2017-12-25

    To explore stiletto needle and needle-knife for influence of double sufficient weight in treating knee osteoarthritis patients. One hundred and thirteen early and medium term knee osteoarthritis patients were randomly divided into three groups, including stiletto needle group(38 cases), needle-knife group (38 cases) and voltaren group (37 cases). In stiletto needle group, there were 13 males and 25 females with an average of(55.87±7.72) years old, treated by stiletto needle once a week, and 2 weeks were a course; there were 11 males and 27 females in needle-knife group with an average of(57.11±7.07) years old, treated by acupotome once a week, and 2 weeks were a course; there were 12 males and 25 females in voltaren group with an average age of(57.62±8.08) years old, treated by votalin emulsion smearing 3 to 5 cm on painful area of knee joint, three times a day for 2 weeks; 36 patients in normal group, including 11 males and 25 females with a mean age of (55.28±7.55) years old, treated with nothing. Gravitational four lattice used to measure bipedal back and forth load before and after treatment in further observe weight-bearing situation among three groups, d value, which was the distance from center of gravity to original point, was measured as a obvervational index, JOA score was used to evaluate clinical effect. Five patients were fall out, including 2 patients in stiletto needle group, 2 patients in needle-knife group and 1 patient in voltaren group. Other 108 patients were followed-up from 28 to 35 d with an average of 30 d, and without untoward effect. There was significant difference in d value between treatment group and control group at 1 month after treatment( P <0.05); there was significant difference in d value among treatment group at 1 month after treatment( P >0.05), and d value was decreased before treatment than that of after treatment. There was no significant difference in JOA score among treatment group after treatment at 1 month( P <0

  19. Endoscopic submucosal dissection for early esophageal neoplasms using the stag beetle knife

    PubMed Central

    Kuwai, Toshio; Yamaguchi, Toshiki; Imagawa, Hiroki; Miura, Ryoichi; Sumida, Yuki; Takasago, Takeshi; Miyasako, Yuki; Nishimura, Tomoyuki; Iio, Sumio; Yamaguchi, Atsushi; Kouno, Hirotaka; Kohno, Hiroshi; Ishaq, Sauid

    2018-01-01

    AIM To determine short- and long-term outcomes of endoscopic submucosal dissection (ESD) using the stag beetle (SB) knife, a scissor-shaped device. METHODS Seventy consecutive patients with 96 early esophageal neoplasms, who underwent ESD using a SB knife at Kure Medical Center and Chugoku Cancer Center, Japan, between April 2010 and August 2016, were retrospectively evaluated. Clinicopathological characteristics of lesions and procedural adverse events were assessed. Therapeutic success was evaluated on the basis of en bloc, histologically complete, and curative or non-curative resection rates. Overall and tumor-specific survival, local or distant recurrence, and 3- and 5-year cumulative overall metachronous cancer rates were also assessed. RESULTS Eligible patients had dysplasia/intraepithelial neoplasia (22%) or early cancers (squamous cell carcinoma, 78%). The median procedural time was 60 min and on average, the lesions measured 24 mm in diameter, yielding 33-mm tissue defects. The en bloc resection rate was 100%, with 95% and 81% of dissections deemed histologically complete and curative, respectively. All procedures were completed without accidental incisions/perforations or delayed bleeding. During follow-up (mean, 35 ± 23 mo), no local recurrences or metastases were observed. The 3- and 5-year survival rates were 83% and 70%, respectively, with corresponding rates of 85% and 75% for curative resections and 74% and 49% for non-curative resections. The 3- and 5-year cumulative rates of metachronous cancer in the patients with curative resections were 14% and 26%, respectively. CONCLUSION ESD procedures using the SB knife are feasible, safe, and effective for treating early esophageal neoplasms, yielding favorable short- and long-term outcomes. PMID:29686470

  20. Endoscopic submucosal tunnel dissection of upper gastrointestinal submucosal tumors: A comparative study of hook knife vs hybrid knife.

    PubMed

    Zhou, Jie-Qiong; Tang, Xiao-Wei; Ren, Yu-Tang; Wei, Zheng-Jie; Huang, Si-Lin; Gao, Qiao-Ping; Zhang, Xiao-Feng; Yang, Jian-Feng; Gong, Wei; Jiang, Bo

    2017-03-14

    To compare the efficacy and safety of a hook knife (HO) with a hybrid knife (HK) during endoscopic submucosal tunnel dissection (ESTD) procedure. Between August 2012 and December 2015, the ESTD procedure was performed for 83 upper GI submucosal lesions, which originated from the muscularis propria layer identified by upper endoscopy and endoscopic ultrasonography. Of these, 34 lesions were treated by a HO, whereas 49 lesions were treated by a HK. Data regarding age, gender, presenting symptoms, tumor location and size, procedure time, complications, en bloc resection rate and others were analyzed and compared between the two groups. There were no significant differences in the age, gender, presenting symptoms and tumor location between the two groups. ESTD was successfully completed in all the patients, and no case was converted to laparoscopy. The mean procedure time was significantly shorter in the HK group than in the HO group (41.3 ± 20.3 min vs 57.2 ± 28.0 min, P = 0.004). The mean frequency of device exchange was 1.4 ± 0.6 in the HK group and significantly less than 3.3 ± 0.6 in the HO group ( P < 0.001). The differences in tumor size and histopathological diagnoses were not significant between the two groups ( P = 0.813, P = 0.363, respectively). Both groups had an equal en bloc resection rate and complete resection rate. Additionally, the complication rate was similar between the two groups ( P = 0.901). During the follow-up, no recurrence occurred in either group. We demonstrate for the first time that HO and HK do not differ in efficacy or safety, but HK reduces the frequency of device exchange and procedure time.

  1. Application of Electrocautery Needle Knife Combined with Balloon Dilatation versus Balloon Dilatation in the Treatment of Tracheal Fibrotic Scar Stenosis.

    PubMed

    Bo, Liyan; Li, Congcong; Chen, Min; Mu, Deguang; Jin, Faguang

    Electrocautery needle knives can largely reduce scar and granulation tissue hyperplasia and play an important role in treating patients with benign stricture. The aim of this retrospective study was to evaluate the efficacy and safety of electrocautery needle knife combined with balloon dilatation versus balloon dilatation alone in the treatment of tracheal stenosis caused by tracheal intubation or tracheotomy. We retrospectively analysed the clinical data of 43 patients with tracheal stenosis caused by tracheotomy or tracheal intubation in our department from January 2013 to January 2016. Among these 43 patients, 23 had simple web-like stenosis and 20 had complex steno sis. All patients were treated under general anaesthesia, and the treatment methods were (1) balloon dilatation alone, (2) needle knife excision of fibrotic tissue combined with balloon dilatation, and (3) needle knife radial incision of fibrotic tissue combined with balloon dilatation. After treatment the symptoms, such as shortness of breath, were markedly improved immediately in all cases. The stenosis degree of patients who were treated with the elec-trocautery needle knife combined with balloon dilatation had better improvement compared with that of those treated with balloon dilatation treatment alone after 3 months (0.45 ± 0.04 vs. 0.67 ± 0.05, p < 0.01), and the proportion of restenosis occurrence that required further treatment was decreased at 6 months (46.9 vs. 81.8%), especially for the web-like stenosis patients, as most of their stenoses dilated with no obvious restenosis and achieved clinical cure. Electrocautery needle knife combined with balloon dilatation is an effective and safe treatment for tracheal fibrotic stenosis compared with balloon dilatation alone. © 2017 S. Karger AG, Basel.

  2. 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

  3. Usefulness of underwater endoscopic submucosal dissection in saline solution with a monopolar knife for colorectal tumors (with videos).

    PubMed

    Nagata, Mitsuru

    2018-05-01

    Generally, colorectal endoscopic submucosal dissection (ESD) is performed with a monopolar knife with CO 2 supply from an endoscope. There are few case reports about underwater ESD (UESD) in saline solution with a bipolar knife. The usefulness and safety of UESD in saline solution with a monopolar knife are unclear. The present study aimed to investigate the usefulness and safety of UESD in saline solution with a monopolar knife for colorectal tumors. This retrospective, observational study on UESD for colorectal tumors included 26 colorectal tumors from 24 patients treated with UESD at our department between October 2015 and February 2017. The characteristics of patients, factors associated with ESD difficulty, treatment results, and variations in blood test data before and after UESD were analyzed. En bloc resection was successful in all lesions without any serious adverse events. The median major diameter of the resected specimens was 30 mm (interquartile range [IQR], 28-35) and of the tumor 22.5 mm (IQR, 17.8-25.3). The median procedure time was 60 minutes (IQR, 45-111) and median speed of dissection 10.4 mm 2 /min (IQR, 6.4-12.2). No cases of perforation occurred. Post-ESD bleeding occurred in only 1 case, and endoscopic hemostasis was achieved. There was no case of electrolyte imbalance requiring treatment after UESD. UESD in saline solution with a monopolar knife for colorectal tumors is useful and safe. UESD has potential advantages that should be further assessed. Copyright © 2018 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

  4. 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

  5. PET-Probe: Evaluation of Technical Performance and Clinical Utility of a Handheld High-Energy Gamma Probe in Oncologic Surgery.

    PubMed

    Gulec, Seza A; Daghighian, Farhad; Essner, Richard

    2016-12-01

    Positron emission tomography (PET) has become an invaluable part of patient evaluation in surgical oncology. PET is less than optimal for detecting lesions <1 cm, and the intraoperative localization of small PET-positive lesions can be challenging as a result of difficulties in surgical exposure. We undertook this investigation to assess the utility of a handheld high-energy gamma probe (PET-Probe) for intraoperative identification of 18 F-deoxyglucose (FDG)-avid tumors. Forty patients underwent a diagnostic whole-body FDG-PET scan for consideration for surgical exploration and resection. Before surgery, all patients received an intravenous injection of 7 to 10 mCi of FDG. At surgery, the PET-Probe was used to determine absolute counts per second at the known tumor site(s) demonstrated by whole-body PET and at adjacent normal tissue (at least 4 cm away from tumor-bearing sites). Tumor-to-background ratios were calculated. Thirty-two patients (80%) underwent PET-Probe-guided surgery with therapeutic intent in a recurrent or metastatic disease setting. Eight patients underwent surgery for diagnostic exploration. Anatomical locations of the PET-identified lesions were neck and supraclavicular (n = 8), axilla (n = 5), groin and deep iliac (n = 4), trunk and extremity soft tissue (n = 3), abdominal and retroperitoneal (n = 19), and lung (n = 2). PET-Probe detected all PET-positive lesions. The PET-Probe was instrumental in localization of lesions in 15 patients that were not immediately apparent by surgical exploration. The PET-Probe identified all lesions demonstrated by PET scanning and, in selected cases, was useful in localizing FDG-avid disease not seen with conventional PET scanning.

  6. Past, Present and Future. Dull Knife Memorial College (Indian Action Program Inc.).

    ERIC Educational Resources Information Center

    1978

    Five vocational training programs as well as academic coursework are offered on the Northern Cheyenne Reservation by Dull Knife Memorial College. Established and operated by the Northern Cheyenne, and located in Lame Deer, Montana, the college was chartered by a tribal ordinance in 1975. Approximately 75 trainees are currently involved in the…

  7. Chief Dull Knife Community Is Strengthening the Northern Cheyenne Language and Culture.

    ERIC Educational Resources Information Center

    Littlebear, Richard E.

    2003-01-01

    Language revitalization programs should focus on whether they want to teach the language, teach about the language, teach with the language, or teach the language for academic credit. A program at Chief Dull Knife College (Montana) teaches the Cheyenne language using the Total Physical Response method, which replicates the manner in which first…

  8. Bipolar plasma vaporization using plasma-cutting and plasma-loop electrodes versus cold-knife transurethral incision for the treatment of posterior urethral stricture: a prospective, randomized study.

    PubMed

    Cai, Wansong; Chen, Zhiyuan; Wen, Liping; Jiang, Xiangxin; Liu, Xiuheng

    2016-01-01

    Evaluate the efficiency and safety of bipolar plasma vaporization using plasma-cutting and plasma-loop electrodes for the treatment of posterior urethral stricture. Compare the outcomes following bipolar plasma vaporization with conventional cold-knife urethrotomy. A randomized trial was performed to compare patient outcomes from the bipolar and cold-knife groups. All patients were assessed at 6 and 12 months postoperatively via urethrography and uroflowmetry. At the end of the first postoperative year, ureteroscopy was performed to evaluate the efficacy of the procedure. The mean follow-up time was 13.9 months (range: 12 to 21 months). If re-stenosis was not identified by both urethrography and ureteroscopy, the procedure was considered "successful". Fifty-three male patients with posterior urethral strictures were selected and randomly divided into two groups: bipolar group (n=27) or cold-knife group (n=26). Patients in the bipolar group experienced a shorter operative time compared to the cold-knife group (23.45±7.64 hours vs 33.45±5.45 hours, respectively). The 12-month postoperative Qmax was faster in the bipolar group than in the cold-knife group (15.54±2.78 ml/sec vs 18.25±2.12 ml/sec, respectively). In the bipolar group, the recurrence-free rate was 81.5% at a mean follow-up time of 13.9 months. In the cold-knife group, the recurrence-free rate was 53.8%. The application of bipolar plasma-cutting and plasma-loop electrodes for the management of urethral stricture disease is a safe and reliable method that minimizes the morbidity of urethral stricture resection. The advantages include a lower recurrence rate and shorter operative time compared to the cold-knife technique.

  9. 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

  10. Direct measures of mechanical energy for knife mill size reduction of switchgrass, wheat straw, and corn stover.

    PubMed

    Bitra, Venkata S P; Womac, Alvin R; Igathinathane, C; Miu, Petre I; Yang, Yuechuan T; Smith, David R; Chevanan, Nehru; Sokhansanj, Shahab

    2009-12-01

    Lengthy straw/stalk of biomass may not be directly fed into grinders such as hammer mills and disc refiners. Hence, biomass needs to be preprocessed using coarse grinders like a knife mill to allow for efficient feeding in refiner mills without bridging and choking. Size reduction mechanical energy was directly measured for switchgrass (Panicum virgatum L.), wheat straw (Triticum aestivum L.), and corn stover (Zea mays L.) in an instrumented knife mill. Direct power inputs were determined for different knife mill screen openings from 12.7 to 50.8 mm, rotor speeds between 250 and 500 rpm, and mass feed rates from 1 to 11 kg/min. Overall accuracy of power measurement was calculated to be +/-0.003 kW. Total specific energy (kWh/Mg) was defined as size reduction energy to operate mill with biomass. Effective specific energy was defined as the energy that can be assumed to reach the biomass. The difference is parasitic or no-load energy of mill. Total specific energy for switchgrass, wheat straw, and corn stover chopping increased with knife mill speed, whereas, effective specific energy decreased marginally for switchgrass and increased for wheat straw and corn stover. Total and effective specific energy decreased with an increase in screen size for all the crops studied. Total specific energy decreased with increase in mass feed rate, but effective specific energy increased for switchgrass and wheat straw, and decreased for corn stover at increased feed rate. For knife mill screen size of 25.4 mm and optimum speed of 250 rpm, optimum feed rates were 7.6, 5.8, and 4.5 kg/min for switchgrass, wheat straw, and corn stover, respectively, and the corresponding total specific energies were 7.57, 10.53, and 8.87 kWh/Mg and effective specific energies were 1.27, 1.50, and 0.24 kWh/Mg for switchgrass, wheat straw, and corn stover, respectively. Energy utilization ratios were calculated as 16.8%, 14.3%, and 2.8% for switchgrass, wheat straw, and corn stover, respectively. These

  11. Multicenter evaluation of a synthetic single-crystal diamond detector for CyberKnife small field size output factors.

    PubMed

    Russo, Serenella; Masi, Laura; Francescon, Paolo; Frassanito, Maria Cristina; Fumagalli, Maria Luisa; Marinelli, Marco; Falco, Maria Daniela; Martinotti, Anna Stefania; Pimpinella, Maria; Reggiori, Giacomo; Verona Rinati, Gianluca; Vigorito, Sabrina; Mancosu, Pietro

    2016-04-01

    The aim of the present work was to evaluate small field size output factors (OFs) using the latest diamond detector commercially available, PTW-60019 microDiamond, over different CyberKnife systems. OFs were measured also by silicon detectors routinely used by each center, considered as reference. Five Italian CyberKnife centers performed OFs measurements for field sizes ranging from 5 to 60mm, defined by fixed circular collimators (5 centers) and by Iris(™) variable aperture collimator (4 centers). Setup conditions were: 80cm source to detector distance, and 1.5cm depth in water. To speed up measurements two diamond detectors were used and their equivalence was evaluated. MonteCarlo (MC) correction factors for silicon detectors were used for comparing the OF measurements. Considering OFs values averaged over all centers, diamond data resulted lower than uncorrected silicon diode ones. The agreement between diamond and MC corrected silicon values was within 0.6% for all fixed circular collimators. Relative differences between microDiamond and MC corrected silicon diodes data for Iris(™) collimator were lower than 1.0% for all apertures in the totality of centers. The two microDiamond detectors showed similar characteristics, in agreement with the technical specifications. Excellent agreement between microDiamond and MC corrected silicon diode detectors OFs was obtained for both collimation systems fixed cones and Iris(™), demonstrating the microDiamond could be a suitable detector for CyberKnife commissioning and routine checks. These results obtained in five centers suggest that for CyberKnife systems microDiamond can be used without corrections even at the smallest field size. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  12. Safety and efficacy of endoscopic submucosal dissection using IT knife nano with clip traction method for early esophageal squamous cell carcinoma.

    PubMed

    Kitagawa, Yoshiyasu; Suzuki, Takuto; Hara, Taro; Yamaguchi, Taketo

    2018-01-01

    Although endoscopic submucosal dissection (ESD) is an accepted and established treatment for early esophageal squamous cell carcinoma (EESCC), it is technically difficult, time consuming, and less safe than endoscopic mucosal resection. To perform ESD safely and more efficiently, we proposed a new technique of esophageal ESD using an IT knife nano with the clip traction method. This study aimed to evaluate the efficacy and safety of ESD using this new technique. We retrospectively reviewed all consecutive cases of esophageal ESD performed using an IT knife nano with the clip traction method at our hospital between March 2013 and January 2017. Therapeutic efficacy and safety were also assessed. A total of 103 patients underwent esophageal ESD using the IT knife nano with the clip traction method. In all cases, we performed en bloc resection. Complete resection was achieved in 100 cases (97.1%). The median operating time was 40 (range 13-230) min. No cases of perforation or delayed bleeding occurred. Although two cases (2.0%) of mediastinal emphysema occurred without visible perforation at endoscopy, all were successfully managed conservatively. The new technique of esophageal ESD using the IT knife nano with the clip traction method appears to be feasible, effective, and safe for EESCC treatment.

  13. Hemorrhoid surgery

    MedlinePlus

    ... a small rubber band around a hemorrhoid to shrink it by blocking blood flow. Stapling a hemorrhoid to block blood flow, causing it to shrink. Using a knife (scalpel) to remove hemorrhoids. You ...

  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. SU-F-T-538: CyberKnife with MLC for Treatment of Large Volume Tumors: A Feasibility Study

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

    Bichay, T; Mayville, A

    2016-06-15

    Purpose: CyberKnife is a well-documented modality for SRS and SBRT treatments. Typical tumors are small and 1–5 fractions are usually used. We determined the feasibility of using CyberKnife, with an InCise multileaf collimator option, for larger tumors undergoing standard dose and fractionation. The intent was to understand the limitation of using this modality for other external beam radiation treatments. Methods: Five tumors from different anatomical sites with volumes from 127.8 cc to 1,320.5 cc were contoured and planned on a Multiplan V5.1 workstation. The target average diameter ranged from 7 cm to 13 cm. The dose fractionation was 1.8–2.0 Gy/fractionmore » and 25–45 fractions for total doses of 45–81 Gy. The sites planned were: pancreas, head and neck, prostate, anal, and esophagus. The plans were optimized to meet conventional dose constraints based on various RTOG protocols for conventional fractionation. Results: The Multiplan treatment planning system successfully generated clinically acceptable plans for all sites studied. The resulting dose distributions achieved reasonable target coverage, all greater than 95%, and satisfactory normal tissue sparing. Treatment times ranged from 9 minutes to 38 minutes, the longest being a head and neck plan with dual targets receiving different doses and with multiple adjacent critical structures. Conclusion: CyberKnife, with the InCise multileaf collimation option, can achieve acceptable dose distributions in large volume tumors treated with conventional dose and fractionation. Although treatment times are greater than conventional accelerator time; target coverage and dose to critical structures can be kept within a clinically acceptable range. While time limitations exist, when necessary CyberKnife can provide an alternative to traditional treatment modalities for large volume tumors.« less

  16. Development of a novel gamma probe for detecting radiation direction

    NASA Astrophysics Data System (ADS)

    Pani, R.; Pellegrini, R.; Cinti, M. N.; Longo, M.; Donnarumma, R.; D'Alessio, A.; Borrazzo, C.; Pergola, A.; Ridolfi, S.; De Vincentis, G.

    2016-01-01

    Spatial localization of radioactive sources is currently a main issue interesting different fields, including nuclear industry, homeland security as well as medical imaging. It is currently achieved using different systems, but the development of technologies for detecting and characterizing radiation is becoming important especially in medical imaging. In this latter field, radiation detection probes have long been used to guide surgery, thanks to their ability to localize and quantify radiopharmaceutical uptake even deep in tissue. Radiolabelled colloid is injected into, or near to, the tumor and the surgeon uses a hand-held radiation detector, the gamma probe, to identify lymph nodes with radiopharmaceutical uptkake. The present work refers to a novel scintigraphic goniometric probe to identify gamma radiation and its direction. The probe incorporates several scintillation crystals joined together in a particular configuration to provide data related to the position of a gamma source. The main technical characteristics of the gamma locator prototype, i.e. sensitivity, spatial resolution and detection efficiency, are investigated. Moreover, the development of a specific procedure applied to the images permits to retrieve the source position with high precision with respect to the currently used gamma probes. The presented device shows a high sensitivity and efficiency to identify gamma radiation taking a short time (from 30 to 60 s). Even though it was designed for applications in radio-guided surgery, it could be used for other purposes, as for example homeland security.

  17. 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

  18. Cutting a Drop of Water Pinned by Wire Loops Using a Superhydrophobic Surface and Knife

    PubMed Central

    Yanashima, Ryan; García, Antonio A.; Aldridge, James; Weiss, Noah; Hayes, Mark A.; Andrews, James H.

    2012-01-01

    A water drop on a superhydrophobic surface that is pinned by wire loops can be reproducibly cut without formation of satellite droplets. Drops placed on low-density polyethylene surfaces and Teflon-coated glass slides were cut with superhydrophobic knives of low-density polyethylene and treated copper or zinc sheets, respectively. Distortion of drop shape by the superhydrophobic knife enables a clean break. The driving force for droplet formation arises from the lower surface free energy for two separate drops, and it is modeled as a 2-D system. An estimate of the free energy change serves to guide when droplets will form based on the variation of drop volume, loop spacing and knife depth. Combining the cutting process with an electrofocusing driving force could enable a reproducible biomolecular separation without troubling satellite drop formation. PMID:23029297

  19. An optimized knife-edge method for on-orbit MTF estimation of optical sensors using powell parameter fitting

    NASA Astrophysics Data System (ADS)

    Han, Lu; Gao, Kun; Gong, Chen; Zhu, Zhenyu; Guo, Yue

    2017-08-01

    On-orbit Modulation Transfer Function (MTF) is an important indicator to evaluate the performance of the optical remote sensors in a satellite. There are many methods to estimate MTF, such as pinhole method, slit method and so on. Among them, knife-edge method is quite efficient, easy-to-use and recommended in ISO12233 standard for the wholefrequency MTF curve acquisition. However, the accuracy of the algorithm is affected by Edge Spread Function (ESF) fitting accuracy significantly, which limits the range of application. So in this paper, an optimized knife-edge method using Powell algorithm is proposed to improve the ESF fitting precision. Fermi function model is the most popular ESF fitting model, yet it is vulnerable to the initial values of the parameters. Considering the characteristics of simple and fast convergence, Powell algorithm is applied to fit the accurate parameters adaptively with the insensitivity to the initial parameters. Numerical simulation results reveal the accuracy and robustness of the optimized algorithm under different SNR, edge direction and leaning angles conditions. Experimental results using images of the camera in ZY-3 satellite show that this method is more accurate than the standard knife-edge method of ISO12233 in MTF estimation.

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

    Mihailescu, Lucian

    This disclosure provides systems, methods, and apparatus related to ion beam therapy. In one aspect, a system includes a position sensitive detector and a collimator. The position sensitive detector configured to detect gamma rays generated by an ion beam interacting with a target. The collimator is positioned between the target and the position sensitive detector. The collimator includes a plurality of knife-edge slits, with a first knife-edge slit intersecting with a second knife-edge slit.

  1. Design and Mechanical Stability Analysis of the Interaction Region for the Inverse Compton Scattering Gamma-Ray Source Using Finite Element Method

    NASA Astrophysics Data System (ADS)

    Khizhanok, Andrei

    Development of a compact source of high-spectral brilliance and high impulse frequency gamma rays has been in scope of Fermi National Accelerator Laboratory for quite some time. Main goal of the project is to develop a setup to support gamma rays detection test and gamma ray spectroscopy. Potential applications include but not limited to nuclear astrophysics, nuclear medicine, oncology ('gamma knife'). Present work covers multiple interconnected stages of development of the interaction region to ensure high levels of structural strength and vibrational resistance. Inverse Compton scattering is a complex phenomenon, in which charged particle transfers a part of its energy to a photon. It requires extreme precision as the interaction point is estimated to be 20 microm. The slightest deflection of the mirrors will reduce effectiveness of conversion by orders of magnitude. For acceptable conversion efficiency laser cavity also must have >1000 finesse value, which requires a trade-off between size, mechanical stability, complexity, and price of the setup. This work focuses on advantages and weak points of different designs of interaction regions as well as in-depth description of analyses performed. This includes laser cavity amplification and finesse estimates, natural frequency mapping, harmonic analysis. Structural analysis is required as interaction must occur under high vacuum conditions.

  2. Effect of raw materials and hardening process on hardness of manually forged knife

    NASA Astrophysics Data System (ADS)

    Balkhaya, Suwarno

    2017-06-01

    Knives are normally made by forging process either using a machine or traditional method by means of hammering process. This present work was conducted to study the effects of steel raw materials and hardening process on the hardness of manually forged knives. The knife samples were made by traditional hammering (forging) process done by local blacksmith. Afterward, the samples were heat treated with two different hardening procedures, the first was based on the blacksmith procedure and the second was systematically done at the laboratory. The forging was done in the temperature ranged between 900-950°C, while the final temperature ranged between 650-675°C. The results showed that knives made of spring steel and heat treated in simulated condition at the laboratory obtained higher level of hardness, i.e. 62 HRC. In general, knives heat treated by local blacksmith had lower level of hardness that those obtained from simulated condition. Therefore, we concluded that the traditional knife quality in term of hardness can be improved by optimizing the heat treatment schedule.

  3. Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter

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

    Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro

    2016-01-28

    Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.

  4. A comparison of two prompt gamma imaging techniques with collimator-based cameras for range verification in proton therapy

    NASA Astrophysics Data System (ADS)

    Lin, Hsin-Hon; Chang, Hao-Ting; Chao, Tsi-Chian; Chuang, Keh-Shih

    2017-08-01

    In vivo range verification plays an important role in proton therapy to fully utilize the benefits of the Bragg peak (BP) for delivering high radiation dose to tumor, while sparing the normal tissue. For accurately locating the position of BP, camera equipped with collimators (multi-slit and knife-edge collimator) to image prompt gamma (PG) emitted along the proton tracks in the patient have been proposed for range verification. The aim of the work is to compare the performance of multi-slit collimator and knife-edge collimator for non-invasive proton beam range verification. PG imaging was simulated by a validated GATE/GEANT4 Monte Carlo code to model the spot-scanning proton therapy and cylindrical PMMA phantom in detail. For each spot, 108 protons were simulated. To investigate the correlation between the acquired PG profile and the proton range, the falloff regions of PG profiles were fitted with a 3-line-segment curve function as the range estimate. Factors including the energy window setting, proton energy, phantom size, and phantom shift that may influence the accuracy of detecting range were studied. Results indicated that both collimator systems achieve reasonable accuracy and good response to the phantom shift. The accuracy of range predicted by multi-slit collimator system is less affected by the proton energy, while knife-edge collimator system can achieve higher detection efficiency that lead to a smaller deviation in predicting range. We conclude that both collimator systems have potentials for accurately range monitoring in proton therapy. It is noted that neutron contamination has a marked impact on range prediction of the two systems, especially in multi-slit system. Therefore, a neutron reduction technique for improving the accuracy of range verification of proton therapy is needed.

  5. SU-F-T-554: Dark Current Effect On CyberKnife Beam Dosimetry

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

    Kim, H; Chang, A

    Purpose: All RF linear accelerators produce dark current to varying degrees when an accelerating voltage and RF input is applied in the absence of electron gun injection. This study is to evaluate how dark current from the linear accelerator of CyberKnife affect the dose in the reference dosimetry. Methods: The G4 CyberKnife system with 6MV photon beam was used in this study. Using the ion chamber and the diode detector, the dose was measured in water with varying time delay between acquiring charges and staring beam-on after applying high-voltage into the linear accelerator. The dose was measured after the timemore » delay with over the range of 0 to 120 seconds in the accelerating high-voltage mode without beam-on, applying 0, 10, 50, 100, and 200 MUs. For the measurements, the collimator of 60 mm was used and the detectors were placed at the depths of 10 cm with the source-to-surface distance of 80 cm. Results: The dark current was constant over time regardless of MU. The dose due to the dark current increased over time linearly with the R-squared value of 0.9983 up to 4.4 cGy for the time 120 seconds. In the dose rate setting of 720 MU/min, the relative dose when applying the accelerating voltage without beam-on was increased over time up to 0.6% but it was less than the leakage radiation resulted from the accelerated head. As the reference dosimetry condition, when 100 MU was delivered after 10 seconds time delay, the relative dose increased by 0.7% but 6.7% for the low MU (10 MU). Conclusion: In the dosimetry using CyberKnife system, the constant dark current affected to the dose. Although the time delay in the accelerating high-voltage mode without beam-on is within 10 seconds, the dose less than 100 cGy can be overestimated more than 1%.« less

  6. 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.

  7. A cross sectional review of patient information available in the World Wide Web on CyberKnife: fallacies and pitfalls.

    PubMed

    Menon, Durgapoorna; Chelakkot, Prameela G; Sunil, Devika; Lakshmaiah, Ashwini

    2017-12-01

    The purpose of this study is to assess the quality of videos available in YouTube on CyberKnife. The term "CyberKnife" was input into the search window of www.youtube.com on a specific date and the first 50 videos were assessed for technical and content issues. The data was tabulated and analysed. The search yielded 32,300 videos in 0.33 s. Among the first 50 analysed, most were professional videos, mostly on CyberKnife in general and for brain tumours. Most of the videos did not mention anything about patient selection or lesion size. The other technical details were covered by most although they seemed muffled by the animations. Many patient videos were recordings of one entire treatment, thus giving future patients an insight on what to expect. Almost half the videos projected glorified views about the treatment technique. The company videos were reasonably accurate and well presented as were many institutional videos, although there was a tendency to gloss over a few points. The glorification of the treatment technique was a disturbing finding. The profound trust of the patients on the health care system is humbling.

  8. The Effects of Swedish Knife Model on Students' Understanding of the Digestive System

    ERIC Educational Resources Information Center

    Cerrah Ozsevgec, Lale; Artun, Huseyin; Unal, Melike

    2012-01-01

    This study was designed to examine the effect of Swedish Knife Model on students' understanding of digestive system. A simple experimental design (pretest-treatment-posttest) was used in the study and internal comparison of the results of the one group was made. The sample consisted of 40 7th grade Turkish students whose ages range from 13 to 15.…

  9. 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.

  10. SU-E-T-281: Reduction of Treatment Times in CyberKnife Prostate SBRT Using a Water Filled Rectal Balloon

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

    Desai, P; Caroprese, B; McKellar, H

    2014-06-01

    Purpose: To illustrate 25% reduction in CyberKnife prostate SBRT treatment times using a water filled rectal balloon. Methods: We perform prostate SBRT using a 3800cGy in 4 fraction regimen prescribed between 51% 59% iso-dose lines to 95% of PTV using a CyberKnife System. The resultant heterogeneous dosimetry is analogous to HDR dosimetry. Our patients are treated in a feet first supine position to decrease treatment couch sag and also to position the prostate anatomy closer to the robot. CT imaging is performed with a Radiadyne Immobiloc rectal balloon filled with 45-50cc water placed firmly inside the patient's rectum. A treatmentmore » plan is developed from this CT study using Multiplan. The patient is treated every other day for 4 days using the rectal balloon for each fraction. Gold fiducials previously implanted inside the prostate are used for tracking by the CyberKnife system. Results: Critical structures comprise the usual GU anatomy of bladder, rectum, urethra, femoral-heads along with emphasis on doses to anterior rectal wall and rectal mucosa. The water filled rectal balloon localizes the rectum, which enables the physician to accurately contour both anterior rectal wall, and rectal mucosa. The balloon also has a gas release valve enabling better patient comfort. Rectum localization enables the CyberKnife system to make fewer corrections resulting in fewer treatment interruptions and time lost to re-adjustment for rectal motion, bowel filling and gas creation. Effective treatment times are reduced by 25% to approximately 45 minutes. Adoption of the balloon has required minimal change to our planning strategy and plan evaluation process. Conclusion: Patient follow-up comparisons show no difference in effectiveness of treatment with and without balloons We conclude that rectal balloons enhance patient comfort and decrease effective treatment times.« less

  11. [Use of esophageal small balloon or papillary sphincter knife in the treatment of stent implantation 
for colorectal malignant obstruction].

    PubMed

    Xiao, Dinghua; Liu, Shaojun; Yan, Hanguang; Wang, Xiaoyan

    2018-05-28

    To explore the function of esophageal small balloon or papillary sphincter knife in the treatment of stent implantation for colorectal malignant obstruction, and to improve the success rate of colonic stent placement in such patients.
 Methods: A total of 49 patients with colorectal cancer complicated with almost complete obstruction or colorectal cancer were enrolled for this study. The esophageal small balloon or papillary sphincter knife was used in the guide wires. The guide wires gradually crossed the tumor gap and they were placed in the contralateral intestinal cavity with balloon progression. X-ray was then used to confirm whether the guide wire was inserted in the lesion intestinal cavity, and then the metal bare stent was inserted.
 Results: The guide wires was successfully inserted with conventional methods in these 49 cases, while they were also successfully placed the guide wire and the stent in the new way.
 Conclusion: For the patients with colorectal cancer complicated with complete obstruction or colorectal cancer located in obviously angled location, the use of esophageal small balloon or papillary sphincter knife can help the guide wire insert. They greatly improve the success rate of stent implantation.

  12. Endoscopic needle-knife treatment for symptomatic esophageal Zenker's diverticulum: A meta-analysis and systematic review.

    PubMed

    Li, Lian Yong; Yang, Yong Tao; Qu, Chang Min; Liang, Shu Wen; Zhong, Chang Qing; Wang, Xiao Ying; Chen, Yan; Spandorfer, Robert M; Christofaro, Sarah; Cai, Qiang

    2018-04-01

    The aim of this study was to assess the efficacy and safety following endoscopic management of Zenker's diverticulum (ZD) using a needle-knife technique. A systematic search of PubMed, Embase and Cochrane library databases was performed. All original studies reporting efficacy and safety of needle-knife technique for treatment of ZD were included. Pooled event rates across studies were expressed with summative statistics. Main outcomes, such as rates of immediate symptomatic response (ISR), adverse events and recurrence, were extracted, pooled and analyzed. Heterogeneity among studies was assessed using the R statistic. The random effects model was used and results were expressed with forest plots and summative statistics. Thirteen studies included 589 patients were enrolled. Pooled event rates for ISR, overall complication, bleeding and perforation were 88% (95% confidence interval [CI] 79-94%), 13% (95% CI 8-22%), 5% (95% CI 3-10%) and 7% (95% CI 4-12%), respectively. The pooled data demonstrated an overall recurrence rate of 14% (95% CI 9-21%). Diverticulum size of at least 4 cm and less than 4 cm demonstrated pooled adverse event rates of 17% (95% CI 10-27%) and 7% (95% CI 2-18%), respectively. When using diverticuloscope as an accessory, pooled ISR and adverse events rates were 84% (95% CI 58-95%) and 10% (95% CI 3-26%), respectively. Flexible endoscopic procedures using needle-knife offers a relatively safe and effective treatment of symptomatic ZD, especially for ZD of <4 cm in diameter. © 2018 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  13. Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter

    NASA Astrophysics Data System (ADS)

    Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.

    2013-10-01

    An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.

  14. Randomized clinical trial comparing cold knife conization of the cervix with and without lateral hemostatic sutures.

    PubMed

    Bueno, Letícia Rossi; Binda, Marcia; Monego, Heleusa; Scherer, Roberta Luísa; Rolim, Karen Machado; Bottini, Alessandra Leal; Fregnani, José H T G; dos Reis, Ricardo

    2015-06-01

    Compare blood loss during cold knife conization of the cervix with and without lateral hemostatic sutures in the cervical branches of the uterine arteries. Randomized clinical trial. Hospital de Clínicas de Porto Alegre (HCPA). 102 patients that underwent cold knife conization. Women that underwent cold knife conization of the cervix were randomized to undergo the procedure with or without lateral hemostatic sutures. blood loss measured in grams. operative time and postoperative intervention. Only the participants were blinded to group assignment. From March 2009 to August 2012, patients were randomly assigned to one of the study groups. There were no differences in amount of blood loss between patients that underwent the procedure with and without sutures (p = 0.39). Operative time was shorter in the group without suture (p = 0.020). There were no differences in intervention due to bleeding (p = 0.20). Blood loss was greater among menstruating women than for menopausal women (p = 0.011). There were no differences in amount of blood lost between smoking and nonsmoking patients (p = 0.082). Lateral hemostatic sutures do not affect the amount of intraoperative bleeding or the number of postoperative interventions. Their use is not necessary because they result in longer operative time, have a higher cost due to the use of suture material and pose the risk of ureter lesion in case the sutures are not placed at a lower position in the cervix. ClinicalTrials. gov identifier: NCT02184975. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

  15. Factors That Influence Surgical Margin State in Patients Undergoing Cold Knife Conization - A Single Center Experience.

    PubMed

    Aluloski, Igor; Tanturovski, Mile; Petrusevska, Gordana; Jovanovic, Rubens; Kostadinova-Kunovska, Slavica

    2017-12-01

    To evaluate the factors that influence the surgical margin state in patients undergoing cold knife conization at the University Clinic of Gynecology and Obstetrics in Skopje, Republic of Macedonia Materials and methods: We have retrospectively analyzed the medical records of all patients that underwent a cold knife conization at our Clinic in 2015. We cross-referenced the surgical margin state with the histopathological diagnosis (LSIL, HSIL or micro-invasive/invasive cancer), menopausal status of the patients, number of pregnancies, surgeon experience, operating time and cone depth. The data was analyzed with the Chi square test, Fisher's exact test for categorical data and Student's T test for continuous data and univariate and multivariate logistical regressions were performed. A total of 246 medical records have neen analyzed, out of which 29 (11.79%) patients had LSIL, 194 (78.86%) had HSIL and 23 (9.34%) patients suffered micro-invasive/invasive cervical cancer. The surgical margins were positive in 78 (31.7%) of the patients. The average age of the patients was 41.13 and 35 (14.23%) of the patients were menopausal. The multivariate logistic regression identified preoperative forceps biopsy of micro-invasive SCC, HSIL or higher cone specimen histology and shorter cone depth as independent predictors of surgical margin involvement in patients undergoing cold knife conization. In the current study, we have found no association between the inherent characteristics of the patient and the surgeon and the surgical margin state after a CKC. The most important predictors for positive margins were the severity of the lesion and the cone depth.

  16. Towards the automatization of the Foucault knife-edge quantitative test

    NASA Astrophysics Data System (ADS)

    Rodríguez, G.; Villa, J.; Martínez, G.; de la Rosa, I.; Ivanov, R.

    2017-08-01

    Given the increasing necessity of simple, economical and reliable methods and instruments for performing quality tests of optical surfaces such as mirrors and lenses, in the recent years we resumed the study of the long forgotten Foucault knife-edge test from the point of view of the physical optics, ultimately achieving a closed mathematical expression that directly relates the knife-edge position along the displacement paraxial axis with the observable irradiance pattern, which later allowed us to propose a quantitative methodology for estimating the wavefront error of an aspherical mirror with precision akin to interferometry. In this work, we present a further improved digital image processing algorithm in which the sigmoidal cost-function for calculating the transient slope-point of each associated intensity-illumination profile is replaced for a simplified version of it, thus making the whole process of estimating the wavefront gradient remarkably more stable and efficient, at the same time, the Fourier based algorithm employed for gradient integration has been replaced as well for a regularized quadratic cost-function that allows a considerably easier introduction of the region of interest (ROI) of the function, which solved by means of a linear gradient conjugate method largely increases the overall accuracy and efficiency of the algorithm. This revised approach of our methodology can be easily implemented and handled by most single-board microcontrollers in the market, hence enabling the implementation of a full-integrated automatized test apparatus, opening a realistic path for even the proposal of a stand-alone optical mirror analyzer prototype.

  17. Recent advances in molecular biology and treatment strategies for intracranial germ cell tumors.

    PubMed

    Huang, Xiang; Zhang, Rong; Mao, Ying; Zhou, Liang-Fu; Zhang, Chao

    2016-08-01

    Intracranial germ cell tumors (IGCTs) are a group of rare pediatric brain tumors which include various subtypes. The current understanding of the etiology of the tumors and their optimal management strategies remain controversial. The data on IGCTs were collected from articles published in the past 20 years, and the origin and etiology of IGCTs at molecular level as well as the relative roles of varied treatment strategies in different prognosis groups according to Matsutani's classification were reviewed. Recent cellular and molecular evidence suggests that IGCTs may arise from the transformation of endogenous brain cells; and findings in the molecular characterization of IGCTs suggest roles of CCND2, RB1, and PRDM14 in the pathogenesis of IGCTs and identify the KIT/RAS and AKT1/mTOR pathways as potential therapeutic targets in future. According to Matsutani's classification of IGCTs, the good prognosis group includes both germinomas and mature teratomas. For germinomas, both radiation alone and reduced-dose radiotherapy in combination with adjuvant chemotherapy are effective, while complete surgical excision is recommended for mature teratomas. In the intermediate prognosis group, immature teratoma has been successfully treated with gamma knife surgery. However, for intermediate prognosis IGCTs other than immature teratomas, gross total resection with adjuvant chemotherapy and radiotherapy or gamma knife surgery may be necessary to achieve cure. In the poor prognosis group, survival outcomes are unsatisfactory, and complete surgical resection combined with more intensive chemotherapy and radiotherapy remains the best available treatment option at this time. IGCTs should be strictly classified according to their pathological categories before administering pathology-specific treatments. Although open microsurgical excision is the traditional surgical strategy for IGCTs, recent publications also support the role of endoscopic surgical options for pineal region

  18. Double Intracavernous Breakage of Sachse's Knife Blade: Management of a Rare Complication Performing Direct Vision Internal Urethrotomy.

    PubMed

    Benincasa, Alfonso; Saita, Alberto; Pinto, Angelo; Pilerci, Carmine; Francesco, Lamberti; Russo, Aniello; Benincasa, Giuseppe

    2017-01-01

    Background: Although the breakage of a Sachse's knife blade is already a rare event while performing optical internal urethrotomy, a double failure appears to be at the same time a unique and a challenging complication to manage since no reference has emerged from literature review. Case Presentation: A male patient, 80 years of age, underwent retreatment of recurrent urethral stricture that occurred after transurethral resection of the prostate. The latter was complicated by severe intraoperative urethrorrhagia; this is the reason he was transferred from another institution where at first a suprapubic cystostomy was carried out, followed by urethral recanalization through internal urethrotomy and finally he underwent intracavernous Sachse's knife blade discharge. Preoperative evaluation included combined retrograde and voiding urethrography and CT to evaluate the complete resolution of the urethral stenosis and to establish the correct location of the blades inside the corpus cavernosum. A transperineal approach to the left corpus cavernosum was carried out with manageable removal of the foreign body and postoperative assessment showed no early considerable complications for the patient. Conclusion: To our knowledge, this is the first case of double breakage of Sachse's knife blade performing optical internal urethrotomy reported in literature. Although it may appear to be an easy procedure, close attention to its execution must always be paid to prevent major complications. A transperineal approach has proven to be effective and safe without creating any further outcomes to the patient.

  19. Striated abrasions from a knife with non-serrated blade--identification of the instrument of crime on the basis of an experiment with material evidence.

    PubMed

    Kaliszan, Michał; Karnecki, Karol; Akçan, Ramazan; Jankowski, Zbigniew

    2011-09-01

    This paper presents an experiment with a knife seized as material evidence in a homicide case. The reason for the experiment was the necessity to determine whether the injuries of the deceased could have been inflicted with this instrument since in the course of the investigation doubt arose as to the origin of linear, parallel scratches around one of the wounds and on the abdominal integuments suggesting a serrated blade. The knife found near the crime scene had a smooth blade and small serrations only on the borderline between its blade and hilt. However, the performed experiment showed that if the knife is directed towards the integuments of the body in a special way, its serrations, even though not located on the blade itself, may leave such striated marks on the body, as those found during the autopsy, suggesting their origin from a serrated blade.

  20. Outcomes of Primary Transsphenoidal Surgery in Cushing Disease: Experience of a Tertiary Center.

    PubMed

    Keskin, Fatma Ela; Ozkaya, Hande Mefkure; Bolayirli, Murat; Erden, Secil; Kadioglu, Pınar; Tanriover, Necmettin; Gazioglu, Nurperi

    2017-10-01

    To report the initial and long-term remission rates and related factors, secondary treatments, and outcomes of a series of patients with Cushing disease (CD). We included 147 consecutive adult patients with CD who underwent primary transsphenoidal surgery (TSS) between 1998 and 2014 in this study. Eighty-two were followed up in the Cerrahpasa Medical Faculty Endocrinology and Metabolism outpatient clinic. Patients were requested to attend a long-term remission assessment; 55 could be contacted, and data for the remaining 27 patients' last visit to the outpatient clinics were reviewed for early and late remission. Six patients were excluded from the study. Magnetic resonance imaging (MRI) findings and pathologic results including mitosis, Ki-67 levels, and P53 in immunostaining of all patients were evaluated. Data of 82 patients with CD with an average age of 36 years [interquartile range: 29-47] were analyzed with a mean follow-up of 7.5 years [interquartile range: 5-10]. Overall initial remission rates were 72.3% after TSS. Among the 82 patients, 16 patients had Gamma Knife radiosurgery and 7 patients underwent adrenalectomy. After these additional treatments, the long-term remission rate was found as 69.7%. The highest remission rates were with microadenomas. Recurrence was most frequently seen in patients without tumor evidence on MRI. Patients with high Ki-67 levels had higher recurrence rates in long-term follow-up (P = 0.02). Life-long follow-up for patients with CD seems essential. Undetectable tumors on MRI before TSS and high Ki-67 immunopositivity were found as risk factors for tumor recurrence. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Cognition in epilepsy: current clinical issues of interest.

    PubMed

    Witt, Juri-Alexander; Helmstaedter, Christoph

    2017-04-01

    This review provides an update and summary of recent neuropsychological findings in epilepsy focusing on three major clinical topics among the many developments in the field. We will critically outline the current state with regard to cognition in new-onset epilepsies, social cognition in epilepsy, and the long-term outcome of epilepsy surgery and the cognitive outcomes of superselective surgical procedures. Current studies indicate that neuropsychological impairments are prevalent already at the onset of epilepsy and even before, social cognition (i.e., emotion recognition and theory of mind) is impaired in different epilepsy populations, the long-term outcome of epilepsy surgery is mostly characterized by a stable or even improved cognitive status, and superselective epilepsy surgeries are associated with a promising neuropsychological outcome. The high prevalence of cognitive deficits around epilepsy onset challenges the assumption that epilepsy is the major cause of cognitive problems and calls for early neuropsychological diagnostics. Social cognition seems to be a relevant domain that is not yet routinely considered in epilepsy. The cognitive long-term outcome of epilepsy surgery is mostly positive. Stereotactic thermocoagulation and gamma knife surgery appear to be cognitively safe procedures.

  2. Cull sow knife-separable lean content evaluation at harvest and lean mass content prediction equation development.

    PubMed

    Abell, Caitlyn E; Stalder, Kenneth J; Hendricks, Haven B; Fitzgerald, Robert F

    2012-07-01

    The objectives of this study were to develop a prediction equation for carcass knife-separable lean within and across USDA cull sow market weight classes (MWC) and to determine carcass and individual primal cut knife separable lean content from cull sows. There were significant percent lean and fat differences in the primal cuts across USDA MWC. The two lighter USDA MWC had a greater percent carcass lean and lower percent fat compared to the two heavier MWC. In general, hot carcass weight explained the majority of carcass lean variation. Additionally, backfat was a significant variation source when predicting cull sow carcass lean. The findings support using a single lean prediction equation across MWC to assist processors when making cull sow purchasing decisions and determine the mix of animals from various USDA MWC that will meet their needs when making pork products with defined lean:fat content. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Bulky Trichomonad Genomes: Encoding a Swiss Army Knife.

    PubMed

    Barratt, Joel; Gough, Rory; Stark, Damien; Ellis, John

    2016-10-01

    The trichomonads are a remarkably successful lineage of ancient, predominantly parasitic protozoa. Recent molecular analyses have revealed extensive duplication of certain genetic loci in trichomonads. Consequently, their genomes are exceptionally large compared to other parasitic protozoa. Retention of these large gene expansions across different trichomonad families raises the question: do these duplications afford an advantage? Many duplicated genes are linked to the parasitic lifestyle and some are regulated differently to their paralogues, suggesting they have acquired new functions. It is proposed that these large genomes encode a Swiss army knife of sorts, packed with a multitude of tools for use in many different circumstances. This may have bestowed trichomonads with the extraordinary versatility that has undoubtedly contributed to their success. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Penetrating brain injury with a metal bar and a knife: Report of two interesting cases.

    PubMed

    Tabibkhooei, Alireza; Taheri, Morteza; Rohani, Sadra; Chanideh, Iran; Rahatlou, Hessam

    2018-04-01

    Introduction Penetrating brain injury (PBI) is uncommon among the civilian population. Here, we report two interesting cases of PBI. Case presentation The first patient was a 20-year-old male who sustained a penetrating head injury with a metal bar during an accident at work. The patient underwent early surgical intervention, and related meningitis was treated with antibiotics. The patient was discharged 45 days later with no deficit. The second patient was a 34-year-old male who was the victim of a violence attack and was admitted to hospital. He was struck by a knife to his right temporal bone. A brain computed tomography scan and magnetic resonance imaging (MRI) demonstrated the tract of the knife within the brain parenchyma. The patient underwent conservative treatment. After several weeks, the patient was discharged in good health. Conclusion Although severe PBI has a poorer prognosis than a blunt brain injury, in treating of these patients, aggressive and timely surgical intervention, proper wide-spectrum antibiotic administration, stringent and diligent care in the intensive-care unit and careful management of the associated complications are mandated.

  5. [Case-control study on needle-knife to cut off the medial branch of the lumbar posterior ramus under C-arm guiding for the treatment of low back pain caused by lumbar facet osteoarthritis].

    PubMed

    Lu, Di; Xu, Wei-xing; Ding, Wei-Guo; Guo, Qiao-Feng; Ma, Gou-ping; Zhu, Wei-min

    2013-03-01

    To study the clinical efficacy of needle-knife to cut off the medial branch of the lumbar posterior ramus under C-arm guiding to treat low back pain caused by lumbar facet osteoarthritis. From July 2009 to June 2011, 60 patients with low back pain caused by lumbar facet osteoarthritis were reviewed,including 34 males and 26 females, ranging in age from 39 to 73 years old,averaged 61.9 years old; the duration of the disease ranged from 6 to 120 months, with a mean of 18.9 months. All the patients were divided into two groups, 30 patients (18 males and 12 females, ranging in age from 39 to 71 years old, needle-knife group) were treated with needle-knife to cut off medial branch of the lumbar posterior ramus under C -arm guiding and the other 30 patients(16 males and 14 females, ranging in age from 41 to 73 years old, hormone injection group) were treated with hormone injection in lumbar facet joint under C-arm guiding. The preoperative JOA scores and the scores at the 1st, 12th and 26th weeks after treatment were analyzed. Before treatment,the JOA scores between the two groups had no significant difference (P= 0.479); after 1 week of treatment, the JOA scores between the two groups had significant difference (P= 0.040), the improvement rate of hormone injection group was superior than that of the needle-knife group,which were (58.73+/-18.20)% in needle-knife group and (71.10+/-22.19)% in hormone injection group; after 12 weeks of treatment, the JOA scores between the two groups had no significant difference(P=0.569), and the improvement rate between the two groups had no significant difference,which were (50.09+/-19.33)% in the needle-knife group and (48.70+/-18.36)%) in the hormone injection group; after 26 weeks of treatment,the JOA scores between the two groups had significant difference (P=0.000), the improvement rate of hormone injection group was superior than that of the needle-knife group,which were (48.56+/-28.24)% in needle-knife group and (15

  6. Emergency endoscopic needle-knife precut papillotomy in acute severe cholangitis resulting from impacted common bile duct stones at duodenal papilla.

    PubMed

    Zheng, Mingwei; Liu, Xufeng; Li, Ning; Li, Wei-Zhi

    2018-03-01

    To evaluate the efficacy and safety of emergency endoscopic needle-knife precut papillotomy in acute severe cholangitis resulting from impacted common bile duct stones at duodenal papilla. Between January 2010 and January 2015, 118 cases of acute severe cholangitis with impacted common bile duct stones at the native papilla underwent emergency endoscopic retrograde cholangiopancreatography (ERCP) and early needle-knife precut papillotomy in a tertiary referral center. Precut techniques were performed according to the different locations of stones in the duodenal papilla. Clinical data about therapy and recovery of the 118 patients were recorded and analyzed. One hundred and eighteen patients underwent emergency ERCP within 24 h after hospitalization, with a total success rate of 100%. The mean operating time was 6.4 ± 4.1 min. Postoperative acute physiology and chronic health evaluation (APACHE) II scores, white blood cell count and liver function improved significantly. The complication rate was 4.2% (5/118); two with hemorrhage and three with acute pancreatitis. There was no procedure-related mortality. Emergency endoscopic needle-knife precut papillotomy is effective and safe for acute severe cholangitis resulting from impacted common bile duct stones at the duodenal papilla. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  7. Accuracy of non-operative identification of the sentinel lymph node using combined gamma and ultrasound scanning.

    PubMed

    Whelehan, P; Vinnicombe, S J; Brown, D C; McLean, D; Evans, A

    2014-08-01

    To assess how accurately the sentinel lymph node (SLN) can be identified percutaneously, using gamma probe and ultrasound technology. Women with breast cancer, scheduled for wide local excision or mastectomy with SLN biopsy (SLNB), were included. Peri-areolar intradermal injection of technetium-99 nanocolloid was performed on the morning of surgery and 1-2 ml of blue dye was injected in the peri-areolar region once the patient was anaesthetized. Prior to surgery, a gamma probe was used over the skin to identify any hot spot that could represent a SLN. Ultrasound, guided by the hot spot, was then used to visualize potential SLNs and guide the insertion of a localizing wire. The accuracy in localizing the SLN by preoperative gamma-probe guided ultrasonography was assessed by comparison to SLNB. A SLN was correctly identified and marked using gamma-probe guided ultrasonography in 44 of 59 cases (75%; 95% CI: 63-86%). This study supports the case for investigating percutaneous gamma probe and ultrasound guided interventions in the axilla in women with breast cancer, as a potential alternative to surgical SLNB. Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  8. Outcomes and management of patients with Cushing's disease without pathological confirmation of tumor resection after transsphenoidal surgery.

    PubMed

    Pouratian, Nader; Prevedello, Daniel M; Jagannathan, Jay; Lopes, M Beatriz; Vance, Mary Lee; Laws, Edward R

    2007-09-01

    Despite the success of transsphenoidal surgery (TSS) for the treatment of Cushing's disease, in a number of cases, an ACTH-staining pituitary adenoma is not identified histologically. The clinical significance of lack of histological confirmation remains unclear. This was a retrospective review of patients treated at the University of Virginia Medical Center. Of 490 TSS procedures for Cushing's disease between 1993 and 2004, we identified 111 cases without histological adenoma confirmation. Remission and recurrence of Cushing's disease were measured. Overall, 50% of these patients achieved remission, a figure lower than for our entire series (79%) and for patients with histological confirmation of an ACTH-staining adenoma (88%) (P < 0.001). Patients with a history of two prior TSS achieved remission less often than patients with a history of fewer TSS (P = 0.026). No other factors influenced remission rates. Although the overall recurrence rate (21%, seven of 33 evaluated) was not different from previously published long-term studies, in three of seven cases of recurrence, early recurrences were noted between 2 and 4 months after remission. In patients who did not achieve remission, the most common and effective treatment options were repeat TSS, gamma-knife radiosurgery, and bilateral adrenalectomy. The lower remission rate in patients without histological evidence of an adenoma is most likely a result of a decreased rate of adenoma extirpation. The incidence of early recurrence may be a unique feature of this patient population; patients without histological confirmation of tumor resection therefore require close and consistent monitoring postoperatively.

  9. [Effects of small needle knife on the substance P in the dorsal root ganglion and spinal cord of rats].

    PubMed

    Wang, Jin-Rong; Wang, Yong-Zhi; Dong, Fu-Hui; Zhong, Hong-Gang; Wang, De-Long; Wang, Xuan

    2010-09-01

    To study the mechanism of synthesis of substance P (SP) in the dorsal root ganglion (DRG) and the release of it in the dorsal horn of the spinal cord of rats after compression of skeletal muscle, and to observe the influence of small needle knife. Sustained pressure of 70 kPa was applied to rats, muscular tissues for 2 hours. The rats were divided into three groups: normal, control and experiment group respectively. In all rats except the six normal ones, the lower legs were compressed once one day. The left leg was considered as the control group, the right left was experiment group, which were divided into the 1st day, the 2nd day and the 3rd day within the two groups. Experiment group was treated with small needle knife after the muscular tissue was compressed. After completing the stimulation, the DRG related to the muscle and part of spinal cord were removed for the qualification of SP-like immunoreactivity using immunohistochemistry. The dark brown stains on the DRG and on the REXed laminae I and II in the dorsal horn of the spinal cord were counted by Image-Pro Plus software. SP-like immunoreactivity in the side treated by the small needle knife was enhanced comparing with the counterpart in DRG in normal group (P < 0.01). The integrated optical density of SP like immunoreactivity of the DRG in the experiment group were significantly reduced compared with the control group (P < 0.05). However, the release of SP from spinal cord in experiment group was lower than that in the control group at the 1st day and the 3rd day (P < 0.01), with the opposite result of the 2nd day. Based on the fact that SP is a nociceptive neurotransmitter, the present study suggests that tension relaxation by small needle knife reduces expression of SP in the DRG, and shows no effects on the release of SP from the spinal cord in short-term (3 days).

  10. Jack-knife stretching promotes flexibility of tight hamstrings after 4 weeks: a pilot study.

    PubMed

    Sairyo, Koichi; Kawamura, Takeshi; Mase, Yasuyoshi; Hada, Yasushi; Sakai, Toshinori; Hasebe, Kiyotaka; Dezawa, Akira

    2013-08-01

    Tight hamstrings are reported to be one of the causes of low back pain. However, there have been few reports on effective stretching procedures for the tight hamstrings. The so-called jack-knife stretch, an active-static type of stretching, can efficiently increase the flexibility of tight hamstrings. To evaluate hamstring tightness before and after the 4-week stretching protocol in healthy volunteer adults and patients aged under 18 years with low back pain. For understanding the hamstrings tightness, we measured two parameters including (1) finger to floor distance (FFD) and (2) pelvis forward inclination angle (PFIA). Eight healthy adult volunteers who had no lumbar or hip problems participated in this study (mean age: 26.8 years). All lacked flexibility and their FFD were positive before the experiment. Subjects performed 2 sets of the jack-knife stretch every day for 4 weeks. One set consisted of 5 repetitions, each held for 5 s. Before and during the 4-week experiment, the FFD and PFIA of toe-touching tests were measured weekly. For 17 of the sports players aged under 18, only FFD was measured. In adult volunteers, FFD was 14.1 ± 6.1 cm before the experiment and decreased to -8.1 ± 3.7 cm by the end of week 4, indicating a gain in flexibility of 22.2 cm. PFIA was 50.6 ± 8.2 before the experiment and 83.8 ± 5.8 degrees after. Before and after the experiment, the differences were significant (p < 0.05). For those aged under 18, FFD was 8.1 ± 8.0 and -9.6 ± 6.8, before and after the stretching, respectively. This difference was significant (p < 0.05). The jack-knife stretch is a useful active-static stretching technique to efficiently increase flexibility of tight hamstrings.

  11. 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

  12. Initial Experience with the Extracorporeal HIFU Knife with 49 Patients: Japanese Experience

    NASA Astrophysics Data System (ADS)

    Ganaha, F.; Okuno, T.; Lee, C. O.; Shimizu, T.; Osako, K.; Oka, S.; Lee, K. H.; Chen, W. Z.; Zhu, H.; Park, S. H.; Qi, Z.; Shi, D.; Song, H. S.

    2005-03-01

    Forty nine patients with 63 tumours were treated with the Chongqing Haifu knife, as an adjunct to intra-arterial chemoinfusion. Treatment targets included breast (20 lesions), liver (16), bone (8), lymph-node (6), soft tissue (4), lung and pleura (4), pancreas (2), kidney (2) and adrenal gland (1). Follow-up contrast MRI was performed at 3 weeks to assess the effects of HIFU ablation. All cases completed the planned treatment. Of 25 lesions treated with the intention of complete tumour ablation, complete necrosis was obtained in 19 lesions (76%) including 4 secondary success cases. Among 32 lesions having partial and palliative treatment, tumour size was decreased in 6 lesions (21%), and good pain control was obtained in 6 out of 7 patients (86%). Skin injury was the most common complication after HIFU (16%), and was mostly a superficial dermal burn that did not necessitate any treatment. However, there was one patient with deep skin injury at an operation scar which resulted in skin perforation. Other adverse events included soft tissue swelling, prolonged fever, anorexia, persistent pain, shortness of the breath, sacroiliac joint fracture and prolonged diarrhoea. In our limited experience, superficial lesions (e.g. breast cancer, bone, soft tissue, lymph-node and pleural metastasis) appear to be good candidates for HIFU treatment. There appears to be a role for the HIFU knife in pain control for patients with bone metastasis and pancreatic cancer.

  13. 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.

  14. Z{gamma}{gamma}{gamma} {yields} 0 Processes in SANC

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

    Bardin, D. Yu., E-mail: bardin@nu.jinr.ru; Kalinovskaya, L. V., E-mail: kalinov@nu.jinr.ru; Uglov, E. D., E-mail: corner@nu.jinr.ru

    2013-11-15

    We describe the analytic and numerical evaluation of the {gamma}{gamma} {yields} {gamma}Z process cross section and the Z {yields} {gamma}{gamma}{gamma} decay rate within the SANC system multi-channel approach at the one-loop accuracy level with all masses taken into account. The corresponding package for numeric calculations is presented. For checking of the results' correctness we make a comparison with the other independent calculations.

  15. Sneaky Gamma-Rays: Using Gravitational Lensing to Avoid Gamma-Gamma-Absorption

    NASA Astrophysics Data System (ADS)

    Boettcher, Markus; Barnacka, Anna

    2014-08-01

    It has recently been suggested that gravitational lensing studies of gamma-ray blazars might be a promising avenue to probe the location of the gamma-ray emitting region in blazars. Motivated by these prospects, we have investigated potential gamma-gamma absorption signatures of intervening lenses in the very-high-energy gamma-ray emission from lensedblazars. We considered intervening galaxies and individual stars within these galaxies. We find that the collective radiation field of galaxies acting as sources of macrolensing are not expected to lead to significant gamma-gamma absorption. Individual stars within intervening galaxies could, in principle, cause a significant opacity to gamma-gamma absorption for VHE gamma-rays if the impact parameter (the distance of closest approach of the gamma-ray to the center of the star) is small enough. However, we find that the curvature of the photon path due to gravitational lensing will cause gamma-ray photons to maintain a sufficiently large distance from such stars to avoid significant gamma-gamma absorption. This re-inforces the prospect of gravitational-lensing studies of gamma-ray blazars without interference due to gamma-gamma absorption due to the lensing objects.

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

    Brezovich, I; Wu, X; Popple, R

    Purpose: To test spatial and dosimetric accuracy of small cranial target irradiation based on 1.5 T MRI scans using static arcs with MLC-defined fields Methods: A plastic (PMMA) phantom simulating a small brain lesion was mounted on a GammaKnife headframe equipped with MRI localizer. The lesion was a 3 mm long, 3.175 mm diameter cylindrical cavity filled with MRI contrast. Radiochromic film passing through the cavity was marked with pin pricks at the cavity center. The cavity was contoured on an MRI image and fused with CT to simulate treatment of a lesion not visible on CT. The transfer ofmore » the target to CT involved registering the MRI contrast cannels of the localizer that were visible on both modalities. Treatments were planned to deliver 800 cGy to the cavity center using multiple static arcs with 5.0×2.4 mm MLC-defined fields. The phantom was aligned on a STx accelerator by registering the conebeam CT with the planning CT. Films from coronal and sagittal planes were scanned and evaluated using ImageJ software Results: Geographic errors in treatment based on 1.5 T scans agreed within 0.33, −0.27 and 1.21 mm in the vertical, lateral and longitudinal dimensions, respectively. The doses delivered to the cavity center were 7.2% higher than planned. The dose distributions were similar to those of a GammaKnife. Conclusion: Radiation can be delivered with an accelerator at mm accuracy to small cranial targets based on 1.5 MRI scans fused to CTs using a standard GammaKnife headframe and MRI localizer. MLC-defined static arcs produce isodose lines very similar to the GammaKnife.« less

  17. SU-G-TeP2-12: IROCHouston and MDAPL SRS Anthropomorphic Phantom Results

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

    Molineu, A; Kry, S; Alvarez, P

    Purpose: To report the results of SRS phantom irradiations Methods: Anthropomorphic SRS head phantoms were sent to institutions participating in NCI sponsored SRS clinical trials and institutions interested in verifying SRS treatment delivery. The phantom shell was purchased from Phantom Laboratory and altered to house dosimetry and imaging inserts. The imaging insert has 1.9 cm diameter spherical target. The dosimetry insert holds two TLD capsules and radiochromic film in the coronal and sagittal planes through the center of the target. Institutions were asked to image, plan and treat the phantom as they would an SRS patient. GammaKnife, CyberKnife and c-armmore » accelerator institutions were asked to cover the target with 15 Gy, 20 Gy and 25 Gy, respectively. Following these guidelines and typical planning protocols for these three types of machines gives roughly 30 Gy to the center of the target for all units. Submission of the DICOM digital data set was required for analysis. Criteria of 5% for TLD results and 85% of pixels passing 5%/3mm gamma analysis were applied beginning in 2013. Results: The phantom was analyzed 269 times between the beginning of 2013 to present. The pass rate is 81%. Nineteen of the irradiation results failed only the TLD criteria, 19 failed only the film criteria and 12 failed both. Irradiations included 32 CyberKnife 23 GammaKnife, 3 TomoTherapy and 211 c-arm units. Planning systems included Eclipse, Ergo, GammaPlan, Hi-Art, iPlan, Monaco, MultiPlan, Pinnacle, RayStation, XiO and XKnife. Irradiations that were not accompanied with DICOM data were not included in this analysis. Conclusion: The phantom is a valuable end-to-end test used to independently verify the accuracy of SRS treatment delivery. This investigation was supported by IROC grant CA180803 awarded by the NCI.« less

  18. Nasopharyngeal carcinoma presented as cavernous sinus tumour.

    PubMed

    Moona, Mohammad Shafi; Mehdi, Itrat

    2011-12-01

    A 32 year Libyan male presented with the complaints of headache and diplopia. He was diagnosed with a cavernous sinus meningioma on the basis of MRI findings but no initial biopsy was taken. Depending on the radiologic diagnosis the patient was treated with gamma knife surgery twice, abroad. During follow up he developed left ear deafness and left cervical lymph adenopathy. An ENT evaluation with biopsy from the nasopharynx and cervical lymph node was taken. The histopathologic diagnosis of the resected tumour showed a nasopharyngeal carcinoma with cervical lymph node metastasis (poorly differentiated lympho-epithelial carcinoma). The cavernous sinus tumour which was initially treated as a meningioma was in fact metastasis from the nasopharyngeal carcinoma, making this an interesting and rare occurrence.

  19. 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.

  20. The Z {yields} cc-bar {yields} {gamma}{gamma}*, Z {yields} bb-bar {yields} {gamma}{gamma}* triangle diagrams and the Z {yields} {gamma}{psi}, Z {yields} {gamma}Y decays

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

    Achasov, N. N., E-mail: achasov@math.nsc.ru

    2011-03-15

    The approach to the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decay study is presented in detail, based on the sum rules for the Z {yields} cc-bar {yields} {gamma}{gamma}* and Z {yields} bb-bar {yields} {gamma}{gamma}* amplitudes and their derivatives. The branching ratios of the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decays are calculated for different hypotheses on saturation of the sum rules. The lower bounds of {Sigma}{sub {psi}} BR(Z {yields} {gamma}{psi}) = 1.95 Multiplication-Sign 10{sup -7} and {Sigma}{sub {upsilon}} BR(Z {yields} {gamma}Y) = 7.23 Multiplication-Sign 10{sup -7} are found. Deviations from the lower bounds are discussed, including the possibilitymore » of BR(Z {yields} {gamma}J/{psi}(1S)) {approx} BR(Z {yields} {gamma}Y(1S)) {approx} 10{sup -6}, that could be probably measured in LHC. The angular distributions in the Z {yields} {gamma}{psi} and Z {yields} {gamma}Y decays are also calculated.« less

  1. Holmium laser vs. conventional (cold knife) direct visual internal urethrotomy for short-segment bulbar urethral stricture: Outcome analysis.

    PubMed

    Jhanwar, Ankur; Kumar, Manoj; Sankhwar, Satya Narayan; Prakash, Gaurav

    2016-01-01

    Our goal was to analyze the outcome between holmium laser and cold knife direct visual internal urethrotomy (DVIU) for short-segment bulbar urethral stricture. We conducted a prospective study comprised of 112 male patients seen from June 2013 to December 2014. Inclusion criterion was short-segment bulbar urethral stricture (≤1.5cm). Exclusion criteria were prior intervention/urethroplasty, pan-anterior urethral strictures, posterior stenosis, urinary tract infection, and those who lost to followup. Patients were divided into two groups; Group A (n=58) included cold knife DVIU and group B (n=54) included holmium laser endourethrotomy patients. Patient followup included uroflowmetry at postoperative Day 3, as well as at three months and six months. Baseline demographics were comparable in both groups. A total of 107 patients met the inclusion criteria and five patients were excluded due to inadequate followup. Mean stricture length was 1.31 ± 0.252 cm (p=0.53) and 1.34 ± 0.251 cm in Groups A and B, respectively. Mean operating time in Group A was 16.3 ± 1.78 min and in Group B was 20.96 ± 2.23 min (p=0.0001). Five patients in Group A had bleeding after the procedure that was managed conservatively by applying perineal compression. Three patients in Group B had fluid extravasation postoperatively. Qmax (ml/s) was found to be statistically insignificant between the two groups at all followups. Both holmium laser and cold knife urethrotomy are safe and equally effective in treating short-segment bulbar urethral strictures in terms of outcome and complication rate. However, holmium laser requires more expertise and is a costly alternative.

  2. 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.

  3. 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

  4. Visual Outcome in Meningiomas Around Anterior Visual Pathways Treated With Linear Accelerator Fractionated Stereotactic Radiotherapy

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

    Stiebel-Kalish, Hadas, E-mail: kalishhadas@gmail.com; Sackler School of Medicine, Tel Aviv University, Tel Aviv; Reich, Ehud

    Purpose: Meningiomas threatening the anterior visual pathways (AVPs) and not amenable for surgery are currently treated with multisession stereotactic radiotherapy. Stereotactic radiotherapy is available with a number of devices. The most ubiquitous include the gamma knife, CyberKnife, tomotherapy, and isocentric linear accelerator systems. The purpose of our study was to describe a case series of AVP meningiomas treated with linear accelerator fractionated stereotactic radiotherapy (FSRT) using the multiple, noncoplanar, dynamic conformal rotation paradigm and to compare the success and complication rates with those reported for other techniques. Patients and Methods: We included all patients with AVP meningiomas followed up atmore » our neuro-ophthalmology unit for a minimum of 12 months after FSRT. We compared the details of the neuro-ophthalmologic examinations and tumor size before and after FSRT and at the end of follow-up. Results: Of 87 patients with AVP meningiomas, 17 had been referred for FSRT. Of the 17 patients, 16 completed >12 months of follow-up (mean 39). Of the 16 patients, 11 had undergone surgery before FSRT and 5 had undergone FSRT as first-line management. Tumor control was achieved in 14 of the 16 patients, with three meningiomas shrinking in size after RT. Two meningiomas progressed, one in an area that was outside the radiation field. The visual function had improved in 6 or stabilized in 8 of the 16 patients (88%) and worsened in 2 (12%). Conclusions: Linear accelerator fractionated RT using the multiple noncoplanar dynamic rotation conformal paradigm can be offered to patients with meningiomas that threaten the anterior visual pathways as an adjunct to surgery or as first-line treatment, with results comparable to those reported for other stereotactic RT techniques.« less

  5. Analysis of the car body stability performance after coupler jack-knifing during braking

    NASA Astrophysics Data System (ADS)

    Guo, Lirong; Wang, Kaiyun; Chen, Zaigang; Shi, Zhiyong; Lv, Kaikai; Ji, Tiancheng

    2018-06-01

    This paper aims to improve car body stability performance by optimising locomotive parameters when coupler jack-knifing occurs during braking. In order to prevent car body instability behaviour caused by coupler jack-knifing, a multi-locomotive simulation model and a series of field braking tests are developed to analyse the influence of the secondary suspension and the secondary lateral stopper on the car body stability performance during braking. According to simulation and test results, increasing secondary lateral stiffness contributes to limit car body yaw angle during braking. However, it seriously affects the dynamic performance of the locomotive. For the secondary lateral stopper, its lateral stiffness and free clearance have a significant influence on improving the car body stability capacity, and have less effect on the dynamic performance of the locomotive. An optimised measure was proposed and adopted on the test locomotive. For the optimised locomotive, the lateral stiffness of secondary lateral stopper is increased to 7875 kN/m, while its free clearance is decreased to 10 mm. The optimised locomotive has excellent dynamic and safety performance. Comparing with the original locomotive, the maximum car body yaw angle and coupler rotation angle of the optimised locomotive were reduced by 59.25% and 53.19%, respectively, according to the practical application. The maximum derailment coefficient was 0.32, and the maximum wheelset lateral force was 39.5 kN. Hence, reasonable parameters of secondary lateral stopper can improve the car body stability capacity and the running safety of the heavy haul locomotive.

  6. Treatment of over 20 mm gastric cancer by endoscopic submucosal dissection using an insulation-tipped diathermic knife

    PubMed Central

    Hirasaki, Shoji; Kanzaki, Hiromitsu; Matsubara, Minoru; Fujita, Kohei; Ikeda, Fusao; Taniguchi, Hideaki; Yumoto, Eiichiro; Suzuki, Seiyuu

    2007-01-01

    AIM: To evaluate the effectiveness of endoscopic submucosal dissection using an insulation-tipped diathermic knife (IT-ESD) for the treatment of patients with over 20 mm early gastric cancer (EGC). METHODS: A total of 112 patients with over 10 mm EGC were treated with IT-ESD at Sumitomo Besshi Hospital and Shikoku Cancer Center in the 5 year period from January 2002 to December 2006, including 40 patients with over 20 mm EGC. We compared patient backgrounds, the one-piece resection rate, complete resection (CR) rate, operation time, bleeding rate, perforation rate between patients with over 20 mm EGC [over 20 mm group (21-40 mm)] and the remaining patients (under 20 mm group). RESULTS: We found no significant difference in the rate of underlying cardiopulmonary disease (over 20 mm group vs under 20 mm group, 5.0% vs 5.6%), one-piece resection rate (95% vs 96%), CR rate (85% vs 89%), operation time (72.3 min vs 66.5 min), bleeding rate (5% vs 4.2%), and perforation rate (0% vs 1.4%) between the 2 groups. Three patients in each group had submucosal invasion and two in each groups underwent additional surgery. CONCLUSION: There was no significant difference in the outcome resulting from IT-ESD between the 2 groups. Our study proves that IT-ESD is a feasible treatment for patients with over 20 mm mucosal gastric cancer although the long-term outcome should be evaluated in the future. PMID:17663514

  7. Fixed Full Arches Supported by Tapered Implants with Knife-Edge Thread Design and Nanostructured, Calcium-Incorporated Surface: A Short-Term Prospective Clinical Study

    PubMed Central

    Bechara, Soheil; Lukosiunas, Algirdas; Kubilius, Ricardas

    2017-01-01

    Purpose. To evaluate implant survival, peri-implant bone loss, and complications affecting fixed full-arch (FFA) restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface. Methods. Between January 2013 and December 2015, all patients referred for implant-supported FFA restorations were considered for enrollment in this study. All patients received implants with a knife-edge thread design and nanostructured calcium-incorporated surface (Anyridge®, Megagen, South Korea) were restored with FFA restorations and enrolled in a recall program. The final outcomes were implant survival, peri-implant bone loss, biologic/prosthetic complications, and “complication-free” survival of restorations. Results. Twenty-four patients were selected. Overall, 215 implants were inserted (130 maxilla, 85 mandible), 144 in extraction sockets and 71 in healed ridges. Thirty-six FFAs were delivered (21 maxilla, 15 mandible): 27 were immediately loaded and 9 were conventionally loaded. The follow-up ranged from 1 to 3 years. Two fixtures failed, yielding an implant survival rate of 95.9% (patient-based). A few complications were registered, for a “complication-free” survival of restorations of 88.9%. Conclusions. FFA restorations supported by implants with a knife-edge thread design and nanostructured, calcium-incorporated surface are successful in the short term, with high survival and low complication rates; long-term studies are needed to confirm these outcomes. PMID:28246595

  8. Gamma oscillations precede interictal epileptiform spikes in the seizure onset zone

    PubMed Central

    Ren, Liankun; Kucewicz, Michal T.; Cimbalnik, Jan; Matsumoto, Joseph Y.; Brinkmann, Benjamin H.; Hu, Wei; Marsh, W. Richard; Meyer, Fredric B.; Stead, S. Matthew

    2015-01-01

    Objective: To investigate the generation, spectral characteristics, and potential clinical significance of brain activity preceding interictal epileptiform spike discharges (IEDs) recorded with intracranial EEG. Methods: Seventeen adult patients with drug-resistant temporal lobe epilepsy were implanted with intracranial electrodes as part of their evaluation for epilepsy surgery. IEDs detected on clinical macro- and research microelectrodes were analyzed using time-frequency spectral analysis. Results: Gamma frequency oscillations (30–100 Hz) often preceded IEDs in spatially confined brain areas. The gamma-IEDs were consistently observed 35 to 190 milliseconds before the epileptiform spike waveforms on individual macro- and microelectrodes. The gamma oscillations associated with IEDs had longer duration (p < 0.001) and slightly higher frequency (p = 0.045) when recorded on microelectrodes compared with clinical macroelectrodes. Although gamma-IEDs comprised only a subset of IEDs, they were strongly associated with electrodes in the seizure onset zone (SOZ) compared with the surrounding brain regions (p = 0.004), in sharp contrast to IEDs without preceding gamma oscillations that were often also detected outside of the SOZ. Similar to prior studies, isolated pathologic high-frequency oscillations in the gamma (30–100 Hz) and higher (100–600 Hz) frequency range, not associated with an IED, were also found to be associated with SOZ. Conclusions: The occurrence of locally generated gamma oscillations preceding IEDs suggests a mechanistic role for gamma in pathologic network activity generating IEDs. The results show a strong association between SOZ and gamma-IEDs. The potential clinical application of gamma-IEDs for mapping pathologic brain regions is intriguing, but will require future prospective studies. PMID:25589669

  9. 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.

  10. 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

  11. 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 ...

  12. Dopamine-dependent scaling of subthalamic gamma bursts with movement velocity in patients with Parkinson’s disease

    PubMed Central

    Neumann, Wolf-Julian; Bock, Antje; Horn, Andreas; Huebl, Julius; Siegert, Sandy; Schneider, Gerd-Helge; Krauss, Joachim K

    2018-01-01

    Gamma synchronization increases during movement and scales with kinematic parameters. Here, disease-specific characteristics of this synchronization and the dopamine-dependence of its scaling in Parkinson’s disease are investigated. In 16 patients undergoing deep brain stimulation surgery, movements of different velocities revealed that subthalamic gamma power peaked in the sensorimotor part of the subthalamic nucleus, correlated positively with maximal velocity and negatively with symptom severity. These effects relied on movement-related bursts of transient synchrony in the gamma band. The gamma burst rate highly correlated with averaged power, increased gradually with larger movements and correlated with symptom severity. In the dopamine-depleted state, gamma power and burst rate significantly decreased, particularly when peak velocity was slower than ON medication. Burst amplitude and duration were unaffected by the medication state. We propose that insufficient recruitment of fast gamma bursts during movement may underlie bradykinesia as one of the cardinal symptoms in Parkinson’s disease. PMID:29388913

  13. 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 ...

  14. Use of radioguided surgery with [111In]-pentetreotide in the management of an ACTH-secreting bronchial carcinoid causing ectopic Cushing's syndrome.

    PubMed

    Grossrubatscher, E; Vignati, F; Dalino, P; Possa, M; Belloni, P A; Vanzulli, A; Bramerio, M; Marocchi, A; Rossetti, O; Zurleni, F; Loli, P

    2005-01-01

    Intraoperative [111In]-pentetreotide scintigraphy with a hand-held gamma detector probe has recently been proposed to increase the intraoperative detection rate of small neuroendocrine tumors and their metastases. We report a case of a 28-yr-old woman with ectopic Cushing's syndrome due to an ACTH-secreting bronchial carcinoid, in whom the use of radioguided surgery improved disease management. At presentation, radiolabeled pentetreotide scintigraphy was the only procedure able to detect the ectopic source of ACTH. After radiologic confirmation, the patient underwent removal of a bronchial carcinoid, with disease persistence. After surgery, pentetreotide scintigraphy showed pathologic uptake in the mediastinum not previously detected at surgery and only subsequently confirmed by radiologic studies. Despite a second thoracic exploration, hormonal, scintigraphic, and radiological evidence of residual disease persisted. Radioguided surgery was then performed using a hand-held gamma probe 48 h after iv administration of a tracer dose of radiolabeled [111In-DTPA-D-Phe1]-pentetreotide, which permitted detection and removal of multiple residual mediastinal lymph node metastases. Clinical and radiologic cure, with no evidence of tracer uptake at pentetreotide scintigraphy, was subsequently observed. The use of an intraoperative gamma counter appears a promising procedure in the management of metastatic ACTH-secreting bronchial carcinoids.

  15. 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.

  16. Anticonvulsant properties of alpha, gamma, and alpha, gamma-substituted gamma-butyrolactones.

    PubMed

    Klunk, W E; Covey, D F; Ferrendelli, J A

    1982-09-01

    Derivatives of gamma-butyrolactone (GBL) substituted on the alpha- and/or gamma-positions were synthesized and tested for their effects on behavior in mice, on the electroencephalographs and blood pressure of paralyzed-ventilated guinea pigs, and on electrical activity of incubated hippocampal slices. Several compounds, including alpha-ethyl-alpha-methyl GBL (alpha-EMGBL), alpha, alpha-dimethyl GBL, alpha, gamma-diethyl-alpha, gamma-dimethyl GBL, and gamma-ethyl-gamma-methyl GBL, prevented seizures induced by pentylenetetrazol, beta-ethyl-beta-methyl-gamma-butyrolactone (beta-EMGBL), picrotoxin, or all three compounds in mice and guinea pigs but had no effect on seizures induced by maximal electroshock or bicuculline. Neither gamma-hydroxybutyrate (GHB) nor alpha-isopropylidine GBL had any anticonvulsant activity. The anticonvulsant alpha-substituted compounds had a potent hypotensive effect and antagonized the hypertensive effect of beta-EMGBL, alpha-EMGBL was tested in incubated hippocampal slices and was found to depress basal activity and antagonize excitation induced by beta-EMGBL. These results demonstrate that alpha-alkyl-substituted GBL and, to a lesser extent, gamma-substituted derivatives are anticonvulsant agents and that their effects are strikingly different from those of GHB or beta-alkyl-substituted GBLs, which are epileptogenic. Possibly beta- and alpha-substituted GBLs act at the same site as agonists and antagonists, respectively.

  17. 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.

  18. [Thinking of therapeutic mechanism of small knife needle in treating closed myofascitis].

    PubMed

    Zhao, Yong; Fang, Wei; Qin, Wei-kai

    2014-09-01

    The authors investigated and discussed therapeutic mechanism of small knife needle in treating closed myofascitis on the basis of pathomechanism of modern medicine and acupuncture theory of TCM among numbers of clinical cases and experimental data. Therapeutic mechanism lies in 6 aspects: (1) Relieve the energy crisis of tenderness point on muscular fasciae; (2) Affect nervous system and reduce induction of harmful stimulating signal; (3) Inhibit aseptic inflammatory reaction on muscular fasciae; (4) Regulate dynamic equilibrium of soft tissue by cutting scar and releasing the conglutination; (5) Increase patients' regional threshold of feeling; (6) Reduce tension and pressure of soft tissue of tenderness point so as to relieve extrusion of nervus cutaneous.

  19. Choledochoscopic high-frequency needle-knife electrotomy for treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy.

    PubMed

    Yang, Yu-Long; Zhang, Cheng; Wu, Ping; Ma, Yue-Feng; Li, Jing-Yi; Zhang, Hong-Wei; Shi, Li-Jun; Lin, Mei-Ju; Yu, Ying

    2016-05-06

    Anastomotic stricture is a complex and substantial complication following Roux-en-Y hepaticojejunostomy. Initially, endoscopic and percutaneous approaches are often attempted, but the gold standard remains surgical biliary reconstruction, especially for refractory stricture. However, this solution leaves much room for improvement, due to the challenging nature of the biliary reconstruction procedure, in which anastomotic stricture may still occur. To investigate the feasibility and effectiveness of choledochoscopic high-frequency needle-knife electrotomy as an intervention in the treatment of anastomotic strictures following Roux-en-Y hepaticojejunostomy. From February 2010 to October 2014, clinical data was collected and retrospectively compared for patients who underwent balloon dilation or/and choledochoscopic high-frequency needle-knife electrotomy for the treatment of anastomotic strictures after Roux-en-Y hepaticojejunostomy. A total of 38 patients underwent successful choledochoscopic treatment and all the anastomotic strictures were removed successfully, 19 of which were treated with electrotomy, 7 with balloon dilation, and 12 with both electrotomy and balloon dilation. Among these groups,the average operating times were 6.9 ± 2.4 min,10.1 ± 6.8 min, and 20.2 ± 13.5 min, respectively. The average stent supporting times were 6.3 ± 0.7 months, 6.5 ± 0.6 months, and 6.1 ± 0.4 respectively. The mean follow-up after stent removal was 42.1 ± 27.4 months, and in 26.3 % (5/19), 28.5 % (2/7) and 16.7 % (2/12) of cases, recurrent anastomotic stricture occurred. Of these 9 total patients with recurrent anastomotic, two patients were successfully rescued by full-covered self-expanding removable metal stents and 7 patients by electrotomy combined with balloon dilation. Choledochoscopic high-frequency needle-knife electrotomy is both feasible and safe in the treatment of anastomotic stricture after Roux

  20. Treatment of gastric epithelial tumours by endoscopic submucosal dissection using an insulated-tip diathermic knife

    PubMed Central

    Hua, Xu Li; Bo, Qian Jun; Gen, Gu Liu; Fei, Lu; Min, Wang Ya; Ming, Li Yu; Sheng, Lu Hua

    2011-01-01

    BACKGROUND: Endoscopic submucosal dissection (ESD) is a promising technique for the treatment of large, pre- and early malignant gastrointestinal lesions. OBJECTIVE: To assess the rates of en bloc resection, incidence of complications, procedure times and therapeutic outcomes of ESD using an insulated-tip diathermic knife; and to investigate predictors of these outcomes based on the final pathological features of biopsy specimens. METHODS: One hundred twenty patients with endoscopically suspected gastric epithelial tumours who were treated with ESD from January 2006 to December 2009 were evaluated. RESULTS: The mean diameter of the gastric epithelial tumours in the present cohort was 1.88 cm. The mean diameter of the resected specimens was 3.33 cm. The en bloc resection rate was 90% (108 of 120). The median length of the operation was 64.6 min. The bleeding and perforation complication rates were 5.0% (six of 120) and 2.5% (three of 120), respectively. Of 10 gastric tumours initially diagnosed as adenocarcinoma on biopsy, four were found to be low-grade dysplasia and six were found to be high-grade dysplasia after resection and final pathological examination. A total of 112 (93.33%) patients underwent curative treatment, eight patients (6.67%) underwent noncurative treatment with ESD, and two patients (1.67%) experienced local recurrence and subsequently underwent surgery. CONCLUSIONS: ESD is a promising local curative treatment option for gastric epithelial tumours, but still carries the risks of bleeding and/or perforation. Differences in the interpretation of histological results among different pathologists and/or between biopsy specimens before ESD and the en bloc tissue specimens after ESD will result in discrepancies. PMID:21321682