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

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

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.

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

PubMed

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

2017-11-01

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

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

PubMed

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

2017-01-01

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

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

PubMed Central

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

2017-01-01

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

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

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

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

2015-11-15

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

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.

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.

Charged-particle stereotactic radiosurgery

NASA Astrophysics Data System (ADS)

Lyman, John T.; Fabrikant, Jacob I.; Frankel, Kenneth A.

1985-05-01

Charged-particle stereotactic radiosurgery is the technique of using accelerated atomic nuclei for the irradiation of a small volume target to a high dose in a short time interval. This is contrasted with conventional radiotherapy where large volumes are treated with many small fractions of photon or electron radiation over a multi-week period. The helium-ion beam used for charged-particle stereotactic radiosurgery at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron is described. This beam is being used for the treatment of inoperable, deep, intracranial arteriovenous malformations (AVMs). Intracranial AVMs are collections of abnormal blood vessels in the brain that may represent a failure of vessels to mature properly and after a long period of slow growth they may produce clinically recognizable neurological symptoms. Based on our experience using narrow beams of helium ions for stereotactic radiosurgical treatment of AVM patients, the characteristics of the treatments are described. Improvements to the technique which are possible by the use of other charged particle beams are discussed.

Stereotactic radiosurgery for multiple brain metastases

NASA Astrophysics Data System (ADS)

Lee, Anna; (Josh Yamada, Yoshiya

2017-01-01

Whole brain radiation therapy has been the traditional treatment of choice for patients with multiple brain metastases. Although stereotactic radiosurgery is widely accepted for the management to up to 4 brain metastases, its use is still controversial in cases of 5 or more brain metastases. Randomized trials have suggested that stereotactic radiosurgery alone is appropriate in up to 4 metastases without concomitant whole brain radiation. Level 1 evidence also suggests that withholding whole brain radiation may also reduce the impact of radiation on neurocognitive function and also may even offer a survival advantage. A recent analysis of a large multicentre prospective database has suggested that there are no differences in outcomes such as the likelihood of new metastasis or leptomeningeal disease in cases of 2-10 brain metastases, nor in overall survival. Hence in the era of prolonged survival with stage IV cancer, stereotactic radiosurgery is a reasonable alternative to whole brain radiation in order to minimize the impact of treatment upon quality of life without sacrificing overall survival.

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

Best of the Radiosurgery Society® Scientific Meeting 2014: stereotactic radiosurgery/stereotactic body radiotherapy treatment of extracranial and intracranial lesions.

PubMed

Mahadevan, Anand; Bucholz, Richard; Gaya, Andrew M; Kresl, John J; Mantz, Constantine; Minnich, Douglas J; Muacevic, Alexander; Medbery, Clinton; Yang, Jun; Caglar, Hale Basak; Davis, Joanne N

2014-12-01

The SRS/SBRT Scientific Meeting 2014, Minneapolis, MN, USA, 7-10 May 2014. The Radiosurgery Society(®), a professional medical society dedicated to advancing the field of stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), held the international Radiosurgery Society Scientific Meeting, from 7-10 May 2014 in Minneapolis (MN, USA). This year's conference attracted over 400 attendants from around the world and featured over 100 presentations (46 oral) describing the role of SRS/SBRT for the treatment of intracranial and extracranial malignant and nonmalignant lesions. This article summarizes the meeting highlights for SRS/SBRT treatments, both intracranial and extracranial, in a concise review.

Linear accelerator stereotactic radiosurgery for trigeminal neuralgia.

PubMed

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

2015-01-01

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

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

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

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

1990-12-01

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

Stereotactic radiosurgery for the treatment of mesial temporal lobe epilepsy.

PubMed

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

2016-12-01

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

Characteristics and Treatments of Large Cystic Brain Metastasis: Radiosurgery and Stereotactic Aspiration

PubMed Central

Kim, Moinay; Cheok, Stephanie; Chung, Lawrance K.; Ung, Nolan; Thill, Kimberly; Voth, Brittany; Kwon, Do Hoon; Kim, Jeong Hoon; Kim, Chang Jin; Tenn, Stephen; Lee, Percy

2015-01-01

Brain metastasis represents one of the most common causes of intracranial tumors in adults, and the incidence of brain metastasis continues to rise due to the increasing survival of cancer patients. Yet, the development of cystic brain metastasis remains a relatively rare occurrence. In this review, we describe the characteristics of cystic brain metastasis and evaluate the combined use of stereotactic aspiration and radiosurgery in treating large cystic brain metastasis. The results of several studies show that stereotactic radiosurgery produces comparable local tumor control and survival rates as other surgery protocols. When the size of the tumor interferes with radiosurgery, stereotactic aspiration of the metastasis should be considered to reduce the target volume as well as decreasing the chance of radiation induced necrosis and providing symptomatic relief from mass effect. The combined use of stereotactic aspiration and radiosurgery has strong implications in improving patient outcomes. PMID:25977901

Stereotactic Radiosurgery and Hypofractionated Radiotherapy for Glioblastoma.

PubMed

Shah, Jennifer L; Li, Gordon; Shaffer, Jenny L; Azoulay, Melissa I; Gibbs, Iris C; Nagpal, Seema; Soltys, Scott G

2018-01-01

Glioblastoma is the most common primary brain tumor in adults. Standard therapy depends on patient age and performance status but principally involves surgical resection followed by a 6-wk course of radiation therapy given concurrently with temozolomide chemotherapy. Despite such treatment, prognosis remains poor, with a median survival of 16 mo. Challenges in achieving local control, maintaining quality of life, and limiting toxicity plague treatment strategies for this disease. Radiotherapy dose intensification through hypofractionation and stereotactic radiosurgery is a promising strategy that has been explored to meet these challenges. We review the use of hypofractionated radiotherapy and stereotactic radiosurgery for patients with newly diagnosed and recurrent glioblastoma. Copyright © 2017 by the Congress of Neurological Surgeons.

Stereotactic radiosurgery for trigeminal neuralgia utilizing the BrainLAB Novalis system.

PubMed

Zahra, Hadi; Teh, Bin S; Paulino, Arnold C; Yoshor, Daniel; Trask, Todd; Baskin, David; Butler, E Brian

2009-12-01

Stereotactic radiosurgery (SRS) is one of the least invasive treatments for trigeminal neuralgia (TN). To date, most reports have been about Cobalt-based treatments (i.e., Gamma Knife) with limited data on image-guided stereotactic linear accelerator treatments. We describe our initial experience of using BrainLAB Novalis stereotactic system for the radiosurgical treatment of TN. A total of 20 patients were treated between July 2004 and February 2007. Each SRS procedure was performed using the BrainLAB Novalis System. Thin cuts MRI images of 1.5 mm thickness were acquired and fused with the simulation CT of each patient. Majority of the patients received a maximum dose of 90 Gy. The median brainstem dose to 1.0 cc and 0.1 cc was 2.3 Gy and 13.5 Gy, respectively. In addition, specially acquired three-dimensional fast imaging sequence employing steady-state acquisition (FIESTA) MRI was utilized to improve target delineation of the trigeminal proximal nerve root entry zone. Barrow Neurological Index (BNI) pain scale for TN was used for assessing treatment outcome. At a median follow-up time of 14.2 months, 19 patients (95%) reported at least some improvement in pain. Eight (40%) patients were completely pain-free and stopped all medications (BNI Grade I) while another 2 (10%) patients also stopped medications but reported occasional pain (BNI Grade II). Another 2 (10%) patients reported no pain and 7 (35%) patients only occasional pain while continuing medications, BNI Grade IIIA and IIIB, respectively. Median time to pain control was 8.5 days (range: 1-70 days). No patient reported severe pain, worsening pain or any pain not controlled on their previously taken medication. Intermittent or persistent facial numbness following treatments occurred in 35% of patients. No other complications were reported. Stereotactic radiosurgery using the BrainLAB Novalis system is a safe and effective treatment for TN. This information is important as more centers are obtaining image

Stereotactic interstitial radiosurgery for cerebral metastases.

PubMed

Curry, William T; Cosgrove, Garth Rees; Hochberg, Fred H; Loeffler, Jay; Zervas, Nicholas T

2005-10-01

The Photon Radiosurgery System (PRS) is a miniature x-ray generator that can stereotactically irradiate intracranial tumors by using low-energy photons. Treatment with the PRS typically occurs in conjunction with stereotactic biopsy, thereby providing diagnosis and treatment in one procedure. The authors review the treatment of patients with brain metastases with the aid of the PRS and discuss the indications, advantages, and limitations of this technique. Clinical characteristics, treatment parameters, neuroimaging-confirmed outcome, and survival were reviewed in all patients with histologically verified brain metastases who were treated with the PRS at the Massachusetts General Hospital between December 1992 and November 2000. Local control of lesions was defined as either stabilization or diminution in the size of the treated tumor as confirmed by Gd-enhanced magnetic resonance imaging. Between December 1992 and November 2000, 72 intracranial metastatic lesions in 60 patients were treated with the PRS. Primary tumors included lung (33 patients), melanoma (15 patients), renal cell (five patients), breast (two patients), esophageal (two patients), colon (one patient), and Merkle cell (one patient) cancers, and malignant fibrous histiocytoma (one patient). Supratentorial metastases were distributed throughout the cerebrum, with only one cerebellar metastasis. The lesions ranged in diameter from 6 to 40 mm and were treated with a minimal peripheral dose of 16 Gy (range 10-20 Gy). At the last follow-up examination (median 6 months), local disease control had been achieved in 48 (81%) of 59 tumors. An actuarial analysis demonstrated that the survival rates at 6 and 12 months were 63 and 34%, respectively. Patients with a single brain metastasis survived a mean of 11 months. Complications included four patients with postoperative seizures, three with symptomatic cerebral edema, two with hemorrhagic events, and three with symptomatic radiation necrosis requiring surgery

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

Fiducial marker placement using endobronchial ultrasound and navigational bronchoscopy for stereotactic radiosurgery: an alternative strategy.

PubMed

Harley, Daniel P; Krimsky, William S; Sarkar, Saiyad; Highfield, David; Aygun, Cengis; Gurses, Burak

2010-02-01

Stereotactic radiosurgery is being increasingly used to treat patients with early-stage non-small cell lung cancers (NSCLC) who are not candidates for surgical resection. Stereotactic radiosurgery usually needs fiducial markers (FMs) for the tracking process. FMs have generally been placed using percutaneous computed axial tomography scan guidance. We report the results of FM placement using endobronchial ultrasound (EBUS) in 43 patients. A multidisciplinary tumor board evaluates NSCLC patients before they are offered stereotactic radiosurgery. In patients selected for stereotactic radiosurgery, FMs were inserted into peripheral, central, and mediastinal tumors using EBUS and, in selected patients, navigational bronchoscopy. Patients underwent repeat computed axial tomography chest scans 2 weeks later to ensure stability of the FMs before beginning stereotactic radiosurgery. Included were 43 consecutive patients (21 men, 22 women; mean age, 74.4 years). Forty-two (98%) had NSC carcinomas (5 recurrences); 1 had a carcinoid tumor. Twenty-two tumors were located in the left lung, 19 in the right lung, 1 at the carina, and 1 pretracheal. Two to 5 FMs were placed in and around all tumor masses using EBUS and, for peripheral lesions, EBUS combined with navigational bronchoscopy. Thirty patients had no displacement of FMs. In the 13 who had displaced 1 or more FMs, the ability to use the remaining FMs for stereotactic radiosurgery was unimpaired. EBUS and navigational bronchoscopy are safe and effective methods to position FMs for preparing patients with both central and peripheral lung cancers for stereotactic radiosurgery. 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

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.

Safety and efficacy of stereotactic radiosurgery for tumors of the spine.

PubMed

Benzil, Deborah L; Saboori, Mehran; Mogilner, Alon Y; Rocchio, Ronald; Moorthy, Chitti R

2004-11-01

The extension of stereotactic radiosurgery treatment of tumors of the spine has the potential to benefit many patients. As in the early days of cranial stereotactic radiosurgery, however, dose-related efficacy and toxicity are not well understood. The authors report their initial experience with stereotactic radiosurgery of the spine with attention to dose, efficacy, and toxicity. All patients who underwent stereotactic radiosurgery of the spine were treated using the Novalis unit at Westchester Medical Center between December 2001 and January 2004 are included in a database consisting of demographics on disease, dose, outcome, and complications. A total of 31 patients (12 men, 19 women; mean age 61 years, median age 63 years) received treatment for 35 tumors. Tumor types included 26 metastases (12 lung, nine breast, five other) and nine primary tumors (four intradural, five extradural). Thoracic tumors were most common (17 metastases and four primary) followed by lumbar tumors (four metastases and four primary). Lesions were treated to the 85 to 90% isodose line with spinal cord doses being less than 50%. The dose per fraction and total dose were selected on the basis of previous treatment (particularly radiation exposure), size of lesion, and proximity to critical structures. Rapid and significant pain relief was achieved after stereotactic radiosurgery in 32 of 34 treated tumors. In patients treated for metastases, pain was relieved within 72 hours and remained reduced 3 months later. Pain relief was achieved with a single dose as low as 500 cGy. Spinal cord isodoses were less than 50% in all patients except those with intradural tumors (mean single dose to spinal cord 268 cGy and mean total dose to spinal cord 689 cGy). Two patients experienced transient radiculitis (both with a biological equivalent dose (BED) > 60 Gy). One patient who suffered multiple recurrences of a conus ependymoma had permanent neurological deterioration after initial improvement

CT Perfusion Imaging as an Early Biomarker of Differential Response to Stereotactic Radiosurgery in C6 Rat Gliomas

PubMed Central

Yeung, Timothy Pok Chi; Kurdi, Maher; Wang, Yong; Al-Khazraji, Baraa; Morrison, Laura; Hoffman, Lisa; Jackson, Dwayne; Crukley, Cathie; Lee, Ting-Yim; Bauman, Glenn; Yartsev, Slav

2014-01-01

Background The therapeutic efficacy of stereotactic radiosurgery for glioblastoma is not well understood, and there needs to be an effective biomarker to identify patients who might benefit from this treatment. This study investigated the efficacy of computed tomography (CT) perfusion imaging as an early imaging biomarker of response to stereotactic radiosurgery in a malignant rat glioma model. Methods Rats with orthotopic C6 glioma tumors received either mock irradiation (controls, N = 8) or stereotactic radiosurgery (N = 25, 12 Gy in one fraction) delivered by Helical Tomotherapy. Twelve irradiated animals were sacrificed four days after stereotactic radiosurgery to assess acute CT perfusion and histological changes, and 13 irradiated animals were used to study survival. Irradiated animals with survival >15 days were designated as responders while those with survival ≤15 days were non-responders. Longitudinal CT perfusion imaging was performed at baseline and regularly for eight weeks post-baseline. Results Early signs of radiation-induced injury were observed on histology. There was an overall survival benefit following stereotactic radiosurgery when compared to the controls (log-rank P<0.04). Responders to stereotactic radiosurgery showed lower relative blood volume (rBV), and permeability-surface area (PS) product on day 7 post-stereotactic radiosurgery when compared to controls and non-responders (P<0.05). rBV and PS on day 7 showed correlations with overall survival (P<0.05), and were predictive of survival with 92% accuracy. Conclusions Response to stereotactic radiosurgery was heterogeneous, and early selection of responders and non-responders was possible using CT perfusion imaging. Validation of CT perfusion indices for response assessment is necessary before clinical implementation. PMID:25329655

The treatment of recurrent brain metastases with stereotactic radiosurgery.

PubMed

Loeffler, J S; Kooy, H M; Wen, P Y; Fine, H A; Cheng, C W; Mannarino, E G; Tsai, J S; Alexander, E

1990-04-01

Between May 1986 and August 1989, we treated 18 patients with 21 recurrent or persistent brain metastases with stereotactic radiosurgery using a modified linear accelerator. To be eligible for radiosurgery, patients had to have a performance status of greater than or equal to 70% and have no evidence of (or stable) systemic disease. All but one patient had received prior radiotherapy, and were treated with stereotactic radiosurgery at the time of recurrence. Polar lesions were treated only if the patient had undergone and failed previous complete surgical resection (10 patients). Single doses of radiation (900 to 2,500 cGy) were delivered to limited volumes (less than 27 cm3) using a modified 6MV linear accelerator. The most common histology of the metastatic lesion was carcinoma of the lung (seven patients), followed by carcinoma of the breast (four patients), and melanoma (four patients). With median follow-up of 9 months (range, 1 to 39), all tumors have been controlled in the radiosurgery field. Two patients failed in the immediate margin of the treated volume and were subsequently treated with surgery and implantation of 125I to control the disease. Radiographic response was dramatic and rapid in the patients with adenocarcinoma, while slight reduction and stabilization occurred in those patients with melanoma, renal cell carcinoma, and sarcoma. The majority of patients improved neurologically following treatment, and were able to be withdrawn from corticosteroid therapy. Complications were limited and transient in nature and no cases of symptomatic radiation necrosis occurred in any patient despite previous exposure to radiotherapy. Stereotactic radiosurgery is an effective and relatively safe treatment for recurrent solitary metastases and is an appealing technique for the initial management of deep-seated lesions as a boost to whole brain radiotherapy.

10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

Code of Federal Regulations, 2010 CFR

2010-01-01

... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

Code of Federal Regulations, 2011 CFR

2011-01-01

... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

Code of Federal Regulations, 2014 CFR

2014-01-01

... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

Code of Federal Regulations, 2013 CFR

2013-01-01

... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

10 CFR 35.600 - Use of a sealed source in a remote afterloader unit, teletherapy unit, or gamma stereotactic...

Code of Federal Regulations, 2012 CFR

2012-01-01

... COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and..., teletherapy unit, or gamma stereotactic radiosurgery unit. A licensee shall use sealed sources in photon...

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

10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

10 CFR 35.615 - Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Safety precautions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.615 Section 35.615 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and...

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

Stereotactic radiosurgery for tremor: systematic review.

PubMed

Martínez-Moreno, Nuria E; Sahgal, Arjun; De Salles, Antonio; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Paddick, Ian; Régis, Jean; Ryu, Sam; Slotman, Ben J; Martínez-Álvarez, Roberto

2018-02-23

OBJECTIVE The aim of this systematic review is to offer an objective summary of the published literature relating to stereotactic radiosurgery (SRS) for tremor and consensus guideline recommendations. METHODS This systematic review was performed up to December 2016. Article selection was performed by searching the MEDLINE (PubMed) and EMBASE electronic bibliographic databases. The following key words were used: "radiosurgery" and "tremor" or "Parkinson's disease" or "multiple sclerosis" or "essential tremor" or "thalamotomy" or "pallidotomy." The search strategy was not limited by study design but only included key words in the English language, so at least the abstract had to be in English. RESULTS A total of 34 full-text articles were included in the analysis. Three studies were prospective studies, 1 was a retrospective comparative study, and the remaining 30 were retrospective studies. The one retrospective comparative study evaluating deep brain stimulation (DBS), radiofrequency thermocoagulation (RFT), and SRS reported similar tremor control rates, more permanent complications after DBS and RFT, more recurrence after RFT, and a longer latency period to clinical response with SRS. Similar tremor reduction rates in most of the reports were observed with SRS thalamotomy (mean 88%). Clinical complications were rare and usually not permanent (range 0%-100%, mean 17%, median 2%). Follow-up in general was too short to confirm long-term results. CONCLUSIONS SRS to the unilateral thalamic ventral intermediate nucleus, with a dose of 130-150 Gy, is a well-tolerated and effective treatment for reducing medically refractory tremor, and one that is recommended by the International Stereotactic Radiosurgery Society.

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).

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

Stereotactic Radiosurgery in the Management of Limited (1-4) Brain Metasteses: Systematic Review and International Stereotactic Radiosurgery Society Practice Guideline.

PubMed

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

2017-11-03

Guidelines regarding stereotactic radiosurgery (SRS) for brain metastases are missing recently published evidence. To conduct a systematic review and provide an objective summary of publications regarding SRS in managing patients with 1 to 4 brain metastases. Using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using PubMed and Medline up to November 2016. A separate search was conducted for SRS for larger brain metastases. Twenty-seven prospective studies, critical reviews, meta-analyses, and published consensus guidelines were reviewed. Four key points came from these studies. First, there is no detriment to survival by withholding whole brain radiation (WBRT) in the upfront management of brain metastases with SRS. Second, while SRS on its own provides a high rate of local control (LC), WBRT may provide further increase in LC. Next, WBRT does provide distant brain control with less need for salvage therapy. Finally, the addition of WBRT does affect neurocognitive function and quality of life more than SRS alone. For larger brain metastases, surgical resection should be considered, especially when factoring lower LC with single-session radiosurgery. There is emerging data showing good LC and/or decreased toxicity with multisession radiosurgery. A number of well-conducted prospective and meta-analyses studies demonstrate good LC, without compromising survival, using SRS alone for patients with a limited number of brain metastases. Some also demonstrated less impact on neurocognitive function with SRS alone. Practice guidelines were developed using these data with International Stereotactic Radiosurgery Society consensus. Copyright © 2017 by the Congress of Neurological Surgeons

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Training for use of remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.690 Section 35.690 Energy NUCLEAR REGULATORY...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and...

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

[Possibility of 3D Printing in Ophthalmology - First Experiences by Stereotactic Radiosurgery Planning Scheme of Intraocular Tumor].

PubMed

Furdová, A; Furdová, Ad; Thurzo, A; Šramka, M; Chorvát, M; Králik, G

Nowadays 3D printing allows us to create physical objects on the basis of digital data. Thanks to its rapid development the use enormously increased in medicine too. Its creations facilitate surgical planning processes, education and research in context of organ transplantation, individualization prostheses, breast forms, and others.Our article describes the wide range of applied 3D printing technology possibilities in ophthalmology. It is focusing on innovative implementation of eye tumors treatment planning in stereotactic radiosurgery irradiation.We analyze our first experience with 3D printing model of the eye in intraocular tumor planning stereotactic radiosurgery. 3D printing, model, Fused Deposition Modelling, stereotactic radiosurgery, prostheses, intraocular tumor.

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.

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

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.

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

Stereotactic Radiosurgery for the Treatment of Primary and Metastatic Spinal Sarcomas

PubMed Central

Balagamwala, Ehsan H.; Angelov, Lilyana; Suh, John H.; Djemil, Toufik; Magnelli, Anthony; Qi, Peng; Zhuang, Tingliang; Godley, Andrew

2016-01-01

Purpose: Despite advancements in local and systemic therapy, metastasis remains common in the natural history of sarcomas. Unfortunately, such metastases are the most significant source of morbidity and mortality in this heterogeneous disease. As a classically radioresistant histology, stereotactic radiosurgery has emerged to control spinal sarcomas and provide palliation. However, there is a lack of data regarding pain relief and relapse following stereotactic radiosurgery. Methods: We queried a retrospective institutional database of patients who underwent spine stereotactic radiosurgery for primary and metastatic sarcomas. The primary outcome was pain relief following stereotactic radiosurgery. Secondary outcomes included progression of pain, radiographic failure, and development of toxicities following treatment. Results: Forty treatment sites were eligible for inclusion; the median prescription dose was 16 Gy in a single fraction. Median time to radiographic failure was 14 months. At 6 and 12 months, radiographic control was 63% and 51%, respectively. Among patients presenting with pain, median time to pain relief was 1 month. Actuarial pain relief at 6 months was 82%. Median time to pain progression was 10 months; at 12 months, actuarial pain progression was 51%. Following multivariate analysis, presence of neurologic deficit at consult (hazard ratio: 2.48, P < .01) and presence of extraspinal bone metastases (hazard ratio: 2.83, P < .01) were associated with pain relief. Greater pain at consult (hazard ratio: 1.92, P < .01), prior radiotherapy (hazard ratio: 4.65, P = .02), and greater number of irradiated vertebral levels were associated with pain progression. Conclusions: Local treatment of spinal sarcomas has remained a challenge for decades, with poor rates of local control and limited pain relief following conventional radiotherapy. In this series, pain relief was achieved in 82% of treatments at 6 months, with half of patients experiencing pain

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.

Stereotactic radiosurgery of brain metastases.

PubMed

Specht, Hanno M; Combs, Stephanie E

2016-09-01

Brain metastases are a common problem in solid malignancies and still represent a major cause of morbidity and mortality. With the ongoing improvement in systemic therapies, the expectations on the efficacy of brain metastases directed treatment options are growing. As local therapies against brain metastases continue to evolve, treatment patterns have shifted from a palliative "one-treatment-fits-all" towards an individualized, patient adapted approach. In this article we review the evidence for stereotactic radiation treatment based on the current literature. Stereotactic radiosurgery (SRS) as a local high precision approach for the primary treatment of asymptomatic brain metastases has gained wide acceptance. It leads to lasting tumor control with only minor side effects compared to whole brain radiotherapy, since there is only little dose delivered to the healthy brain. The same holds true for hypofractionated stereotactic radiotherapy (HFSRT) for large metastases or for lesions close to organs at risk (e.g. the brainstem). New treatment indications such as neoadjuvant SRS followed by surgical resection or postoperative local therapy to the resection cavity show promising data and are also highlighted in this manuscript. With the evolution of local treatment options, optimal patient selection becomes more and more crucial. This article aims to aid decision making by outlining prognostic factors, treatment techniques and indications and common dose prescriptions.

Frameless stereotactic radiosurgery with a bite-plate: our experience with brain metastases.

PubMed

Furuse, M; Aoki, T; Takagi, T; Takahashi, J A; Ishikawa, M

2008-12-01

Non-invasive frameless stereotactic radiosurgical systems have recently been developed. We report our experience of frameless stereotactic radiosurgery (SRS) with a bite-plate for brain metastases. Between February 2002 and December 2005, 147 patients with brain metastases were treated with C-arm linear accelerator-based SRS and 122 patients were followed up by our institute. An optic tracking system with infrared light-emitting diodes was used for real-time monitoring. A bite-plate with fiducial markers was applied as a first-line method for frameless SRS. Head-ring fixation was used in patients lacking teeth. Lung carcinomas (63%) were the most common primary tumors, followed by breast carcinomas (13%). Ninety patients underwent radiosurgery with a bite-plate and 32 patients underwent fixation of a head ring. Males were significantly more predominant in the head-ring group (26 men and 6 women), compared with the bite-plate group (47 men and 43 women, p < 0.01). The average age (62 years) in the bite-plate group was significantly younger than that (68 years) in the head-ring group (p < 0.01). The median survival time was 12.0 months in the bite-plate group and 8.0 months in the head-ring group (p = 0.0621). Nine patients who had brain metastases in or close to the brain stem were treated with fractionated stereotactic radiotherapy. The frameless stereotactic radiosurgical system with a bite-plate is safe and effective for the treatment of brain metastasis. Elderly male patients sometimes are edentulous and require placement of a head ring for radiosurgery.

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

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.

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.

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.

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

Delayed vertebral body collapse after stereotactic radiosurgery and radiofrequency ablation: Case report with histopathologic-MRI correlation.

PubMed

Wallace, Adam N; Vyhmeister, Ross; Hsi, Andy C; Robinson, Clifford G; Chang, Randy O; Jennings, Jack W

2015-12-01

Stereotactic radiosurgery and percutaneous radiofrequency ablation are emerging therapies for pain palliation and local control of spinal metastases. However, the post-treatment imaging findings are not well characterized and the risk of long-term complications is unknown. We present the case of a 46-year-old woman with delayed vertebral body collapse after stereotactic radiosurgery and radiofrequency ablation of a painful lumbar metastasis. Histopathologic-MRI correlation confirmed osteonecrosis as the underlying etiology and demonstrated that treatment-induced vascular fibrosis and tumor progression can have identical imaging appearances. © The Author(s) 2015.

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.

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.

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

Is it sufficient to repeat LINEAR accelerator stereotactic radiosurgery in choroidal melanoma?

PubMed

Furdova, A; Horkovicova, K; Justusova, P; Sramka, M

One day session LINAC based stereotactic radiosurgery (SRS) at LINAC accelerator is a method of "conservative" attitude to treat the intraocular malignant uveal melanoma. We used model Clinac 600 C/D Varian (system Aria, planning system Corvus version 6.2 verification IMRT OmniPro) with 6 MeV X by rigid immobilization of the eye to the Leibinger frame. The stereotactic treatment planning after fusion of CT and MRI was optimized according to the critical structures (lens, optic nerve, also lens and optic nerve at the contralateral side, chiasm). The first plan was compared and the best plan was applied for therapy at C LINAC accelerator. The planned therapeutic dose was 35.0 Gy by 99 % of DVH (dose volume histogram). In our clinical study in the group of 125 patients with posterior uveal melanoma treated with SRS, in 2 patients (1.6 %) was repeated SRS indicated. Patient age of the whole group ranged from 25 to 81 years with a median of 54 TD was 35.0 Gy. In 2 patients after 5 year interval after stereotactic radiosurgery for uveal melanoma stage T1, the tumor volume increased to 50 % of the primary tumor volume and repeated SRS was necessary. To find out the changes in melanoma characteristics after SRS in long term interval after irradiation is necessary to follow up the patient by an ophthalmologist regularly. One step LINAC based stereotactic radiosurgery with a single dose 35.0 Gy is one of treatment options to treat T1 to T3 stage posterior uveal melanoma and to preserve the eye globe. In some cases it is possible to repeat the SRS after more than 5 year interval (Fig. 8, Ref. 23).

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.

Technical Note: Evaluation of the systematic accuracy of a frameless, multiple image modality guided, linear accelerator based stereotactic radiosurgery system

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

Wen, N., E-mail: nwen1@hfhs.org; Snyder, K. C.; Qin, Y.

2016-05-15

Purpose: To evaluate the total systematic accuracy of a frameless, image guided stereotactic radiosurgery system. Methods: The localization accuracy and intermodality difference was determined by delivering radiation to an end-to-end prototype phantom, in which the targets were localized using optical surface monitoring system (OSMS), electromagnetic beacon-based tracking (Calypso®), cone-beam CT, “snap-shot” planar x-ray imaging, and a robotic couch. Six IMRT plans with jaw tracking and a flattening filter free beam were used to study the dosimetric accuracy for intracranial and spinal stereotactic radiosurgery treatment. Results: End-to-end localization accuracy of the system evaluated with the end-to-end phantom was 0.5 ± 0.2more » mm with a maximum deviation of 0.9 mm over 90 measurements (including jaw, MLC, and cone measurements for both auto and manual fusion) for single isocenter, single target treatment, 0.6 ± 0.4 mm for multitarget treatment with shared isocenter. Residual setup errors were within 0.1 mm for OSMS, and 0.3 mm for Calypso. Dosimetric evaluation based on absolute film dosimetry showed greater than 90% pass rate for all cases using a gamma criteria of 3%/1 mm. Conclusions: The authors’ experience demonstrates that the localization accuracy of the frameless image-guided system is comparable to robotic or invasive frame based radiosurgery systems.« less

Short-term tumor control and acute toxicity after stereotactic radiosurgery for glomus jugulare tumors.

PubMed

Poznanovic, Sheri A; Cass, Stephen P; Kavanagh, Brian D

2006-03-01

Glomus jugulare tumors (GJT) have traditionally been treated by surgery or fractionated external beam radiation therapy (XRT). This study evaluates acute toxicity and short-term efficacy of single-fraction stereotactic radiosurgery (SRS) for the treatment of GJT. Eight patients (age range 28-74) with GJT underwent SRS (Brainlab linear accelerator) as primary treatment. A nominal dose of 15-16 Gy was prescribed. After undergoing SRS, 7 of 8 patients (87.5%) reported complete resolution of presenting symptoms. Follow-up MRIs showed tumor stabilization in 100% of patients. Transient vertigo occurred in one patient. One patient suffered acute GI upset and transient lower cranial neuropathy. Stereotactic radiosurgery is an effective alternative for patients with GJT in achieving tumor control and resolution of symptoms. C-4.

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

Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas.

PubMed

Tu, Albert; Gooderham, Peter; Mick, Paul; Westerberg, Brian; Toyota, Brian; Akagami, Ryojo

2015-08-01

Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation-treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients.

Stereotactic Radiosurgery versus Natural History in Patients with Growing Vestibular Schwannomas

PubMed Central

Tu, Albert; Gooderham, Peter; Mick, Paul; Westerberg, Brian; Toyota, Brian; Akagami, Ryojo

2015-01-01

Objective To describe our experience with stereotactic radiosurgery and its efficacy on growing tumors, and then to compare this result with the natural history of a similar cohort of non-radiation–treated lesions. Study Design A retrospective chart review and cohort comparison. Methods The long-term control rates of patients having undergone radiosurgery were collected and calculated, and this population was then compared with a group of untreated patients from the same period of time with growing lesions. Results A total of 61 patients with growing vestibular schwannomas treated with radiosurgery were included. After a mean of 160 months, we observed a control rate of 85.2%. When compared with a group of 36 patients with growing tumors who were yet to receive treatment (previously published), we found a corrected control rate or relative risk reduction of only 76.8%. Conclusion Radiosurgery for growing vestibular schwannomas is less effective than previously reported in unselected series. Although radiosurgery still has a role in managing this disease, consideration should be given to the actual efficacy that may be calculated when the natural history is known. We hope other centers will similarly report their experience on this cohort of patients. PMID:26225318

Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3

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

Cusumano, Davide, E-mail: davide.cusumano@unimi.it; Fumagalli, Maria L.; Marchetti, Marcello

2015-10-01

Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses usingmore » this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk.« less

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.

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.

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.

Multisession stereotactic radiosurgery for large benign brain tumors of >3cm- early clinical outcomes

PubMed Central

Memon, Muhammad Ali; Ahmed, Usman; Saleem, Muhammad Abid; Bhatti, Amer Iqtidar; Ahmed, Naveed; Hashim, Abdul Sattar M.

2012-01-01

Objective To evaluate the clinical outcome of linear accelerator based multisession stereotactic radiosurgery (SRS) for large benign brain tumors of >3cm. Methods Between June 2009 and May 2011, 35 patients having large benign brain tumors of >3cm (≥15 cm3) were treated by multisession stereotactic radiosurgery. This retrospective study was carried out at Neurospinal & Medical Institute Karachi. There were 17 (48.6 %) males and 18(51.4 %) females. Median age was 36 years (range: 13-65 years). Median target volume was 49.4 cm3 (range: 15-184 cm3). The median marginal dose was 25 Gy (range: 20–27.5Gy) prescribed to a median 75% isodose line (range: 65-100 %). Median number of 5 fractions were used ranging 3-5 fractions. Results All the patients tolerated treatment very well. 21 (58.3%) patients had remarkable clinical improvement of neurological symptoms, 14 (38.9%) patients had stable symptoms, and only one patient had transient worsening of symptoms. No permanent neurological damage or radiation injury was seen. Radiologically, 9 (25.7%) patients achieved reduction in size of the tumor, 26(74.3 %) patients were having stable disease, and overall control rate was found to be 100 %. Median follow-up time from the end of SRS was 6.4 months (range: 1-22.5months). Conclusion Linear accelerator based multisession stereotactic radiosurgery for large benign brain tumors of >3cm is effective and well tolerated. PMID:29296340

Stereotactic Radiosurgery for Benign (World Health Organization Grade I) Cavernous Sinus Meningiomas-International Stereotactic Radiosurgery Society (ISRS) Practice Guideline: A Systematic Review.

PubMed

Lee, Cheng-Chia; Trifiletti, Daniel M; Sahgal, Arjun; DeSalles, Antonio; Fariselli, Laura; Hayashi, Motohiro; Levivier, Marc; Ma, Lijun; Álvarez, Roberto Martínez; Paddick, Ian; Regis, Jean; Ryu, Samuel; Slotman, Ben; Sheehan, Jason

2018-03-15

Stereotactic radiosurgery (SRS) has become popular as a standard treatment for cavernous sinus (CS) meningiomas. To summarize the published literature specific to the treatment of CS meningioma with SRS found through a systematic review, and to create recommendations on behalf of the International Stereotactic Radiosurgery Society. Articles published from January 1963 to December 2014 were systemically reviewed. Three electronic databases, PubMed, EMBASE, and The Cochrane Central Register of Controlled Trials, were searched. Publications in English with at least 10 patients (each arm) were included. Of 569 screened abstracts, a total of 49 full-text articles were included in the analysis. All studies were retrospective. Most of the reports had favorable outcomes with 5-yr progression-free survival (PFS) rates ranging from 86% to 99%, and 10-yr PFS rates ranging from 69% to 97%. The post-SRS neurological preservation rate ranged from 80% to 100%. Resection can be considered for the treatment of larger (>3 cm in diameter) and symptomatic CS meningioma in patients both receptive to and medically eligible for open surgery. Adjuvant or salvage SRS for residual or recurrent tumor can be utilized depending on factors such as tumor volume and proximity to adjacent critical organs at risk. The literature is limited to level III evidence with respect to outcomes of SRS in patients with CS meningioma. Based on the observed results, SRS offers a favorable benefit to risk profile for patients with CS meningioma.

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

Dosimetric verification of stereotactic radiosurgery/stereotactic radiotherapy dose distributions using Gafchromic EBT3.

PubMed

Cusumano, Davide; Fumagalli, Maria L; Marchetti, Marcello; Fariselli, Laura; De Martin, Elena

2015-01-01

Aim of this study is to examine the feasibility of using the new Gafchromic EBT3 film in a high-dose stereotactic radiosurgery and radiotherapy quality assurance procedure. Owing to the reduced dimensions of the involved lesions, the feasibility of scanning plan verification films on the scanner plate area with the best uniformity rather than using a correction mask was evaluated. For this purpose, signal values dispersion and reproducibility of film scans were investigated. Uniformity was then quantified in the selected area and was found to be within 1.5% for doses up to 8 Gy. A high-dose threshold level for analyses using this procedure was established evaluating the sensitivity of the irradiated films. Sensitivity was found to be of the order of centiGray for doses up to 6.2 Gy and decreasing for higher doses. The obtained results were used to implement a procedure comparing dose distributions delivered with a CyberKnife system to planned ones. The procedure was validated through single beam irradiation on a Gafchromic film. The agreement between dose distributions was then evaluated for 13 patients (brain lesions, 5 Gy/die prescription isodose ~80%) using gamma analysis. Results obtained using Gamma test criteria of 5%/1 mm show a pass rate of 94.3%. Gamma frequency parameters calculation for EBT3 films showed to strongly depend on subtraction of unexposed film pixel values from irradiated ones. In the framework of the described dosimetric procedure, EBT3 films proved to be effective in the verification of high doses delivered to lesions with complex shapes and adjacent to organs at risk. Copyright © 2015 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.

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

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

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.

Citation measures in stereotactic radiosurgery: publication across a discipline.

PubMed

Kondziolka, Douglas

2011-01-01

It is possible to judge the impact of scientific research by the number of citations a publication has received. We identified the most cited works in the field of stereotactic radiosurgery to study the evolution of this field from the perspective of publication. A Web of Science search was performed for articles that included the word 'radiosurgery' in the title. We studied the reports with >100 citations. A total of 5,532 published works were available for study between 1951 and 2010. Eighty-five articles had ≥ 100 citations, and these were published in 19 separate journals. The majority were published in the International Journal of Radiation Oncology, Biology and Physics, the Journal of Neurosurgery and Neurosurgery. The most common topics included brain metastasis management (n = 20), arteriovenous malformations (n = 17), vestibular schwannomas (n = 9), technologies (n = 9), meningiomas (n = 8) and dose response/radiobiology (n = 6). Fifty-seven percent of the articles were published in the last 10 years. The first radiosurgery report by Leksell (1951) initiated the field. The 1980s were a period of new technology development followed in the 1990s by introductory articles on specific indications that consisted mainly of retrospective case series. More sophisticated higher level evidence reports were published in the last decade. The most significant works in radiosurgery include initial technology descriptions, multicenter studies with large numbers of patients, randomized clinical trials and reports that provide dose prescription guidelines. Copyright © 2011 S. Karger AG, Basel.

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.

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.

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

PubMed

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

2003-08-15

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

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

Stereotactic Radiosurgery for Patients With Brain Metastases From Small Cell Lung Cancer

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

Wegner, Rodney E.; Olson, Adam C.; Kondziolka, Douglas

2011-11-01

Background: Patients with small-cell lung cancer have a high likelihood of developing brain metastases. Many of these patients will have prophylactic cranial irradiation (PCI) or eventually undergo whole brain radiation therapy (WBRT). Despite these treatments, a large number of these patients will have progression of their intracranial disease and require additional local therapy. Stereotactic radiosurgery (SRS) is an important treatment option for such patients. Methods: We retrospectively reviewed the charts of 44 patients with brain metastases from small-cell lung cancer treated with gamma knife SRS. Multivariate analysis was used to determine significant prognostic factors influencing survival. Results: The median follow-upmore » from SRS in this patient population was 9 months (1-49 months). The median overall survival (OS) was 9 months after SRS. Karnofsky performance status (KPS) and combined treatment involving WBRT and SRS within 4 weeks were the two factors identified as being significant predictors of increased OS (p = 0.033 and 0.040, respectively). When comparing all patients, patients treated with a combined approach had a median OS of 14 months compared to 6 months if SRS was delivered alone. We also compared the OS times from the first definitive radiation: WBRT, WBRT and SRS if combined therapy was used, and SRS if the patient never received WBRT. The median survival for those groups was 12, 14, and 13 months, respectively, p = 0.19. Seventy percent of patients had follow-up magnetic resonance imaging available for review. Actuarial local control at 6 months and 12 months was 90% and 86%, respectively. Only 1 patient (2.2%) had symptomatic intracranial swelling related to treatment, which responded to a short course of steroids. New brain metastases outside of the treated area developed in 61% of patients at a median time of 7 months; 81% of these patients had received previous WBRT. Conclusions: Stereotactic radiosurgery for small-cell lung

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

Stereotactic radiosurgery for trigeminal neuralgia: a systematic review.

PubMed

Tuleasca, Constantin; Régis, Jean; Sahgal, Arjun; De Salles, Antonio; Hayashi, Motohiro; Ma, Lijun; Martínez-Álvarez, Roberto; Paddick, Ian; Ryu, Samuel; Slotman, Ben J; Levivier, Marc

2018-04-27

OBJECTIVES The aims of this systematic review are to provide an objective summary of the published literature specific to the treatment of classical trigeminal neuralgia with stereotactic radiosurgery (RS) and to develop consensus guideline recommendations for the use of RS, as endorsed by the International Society of Stereotactic Radiosurgery (ISRS). METHODS The authors performed a systematic review of the English-language literature from 1951 up to December 2015 using the Embase, PubMed, and MEDLINE databases. The following MeSH terms were used in a title and abstract screening: "radiosurgery" AND "trigeminal." Of the 585 initial results obtained, the authors performed a full text screening of 185 studies and ultimately found 65 eligible studies. Guideline recommendations were based on level of evidence and level of consensus, the latter predefined as at least 85% agreement among the ISRS guideline committee members. RESULTS The results for 65 studies (6461 patients) are reported: 45 Gamma Knife RS (GKS) studies (5687 patients [88%]), 11 linear accelerator (LINAC) RS studies (511 patients [8%]), and 9 CyberKnife RS (CKR) studies (263 patients [4%]). With the exception of one prospective study, all studies were retrospective. The mean maximal doses were 71.1-90.1 Gy (prescribed at the 100% isodose line) for GKS, 83.3 Gy for LINAC, and 64.3-80.5 Gy for CKR (the latter two prescribed at the 80% or 90% isodose lines, respectively). The ranges of maximal doses were as follows: 60-97 Gy for GKS, 50-90 Gy for LINAC, and 66-90 Gy for CKR. Actuarial initial freedom from pain (FFP) without medication ranged from 28.6% to 100% (mean 53.1%, median 52.1%) for GKS, from 17.3% to 76% (mean 49.3%, median 43.2%) for LINAC, and from 40% to 72% (mean 56.3%, median 58%) for CKR. Specific to hypesthesia, the crude rates (all Barrow Neurological Institute Pain Intensity Scale scores included) ranged from 0% to 68.8% (mean 21.7%, median 19%) for GKS, from 11.4% to 49.7% (mean 27

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

ASSOCIATION BETWEEN COMPUTED TOMOGRAPHIC CHARACTERISTICS AND FRACTURES FOLLOWING STEREOTACTIC RADIOSURGERY IN DOGS WITH APPENDICULAR OSTEOSARCOMA.

PubMed

Kubicek, Lyndsay; Vanderhart, Daniel; Wirth, Kimberly; An, Qi; Chang, Myron; Farese, James; Bova, Francis; Sudhyadhom, Atchar; Kow, Kelvin; Bacon, Nicholas J; Milner, Rowan

2016-05-01

The objective of this observational, descriptive, retrospective study was to report CT characteristics associated with fractures following stereotactic radiosurgery in canine patients with appendicular osteosarcoma. Medical records (1999 and 2012) of dogs that had a diagnosis of appendicular osteosarcoma and undergone stereotactic radiosurgery were reviewed. Dogs were included in the study if they had undergone stereotactic radiosurgery for an aggressive bone lesion with follow-up information regarding fracture status, toxicity, and date and cause of death. Computed tomography details, staging, chemotherapy, toxicity, fracture status and survival data were recorded. Overall median survival time (MST) and fracture rates of treated dogs were calculated. CT characteristics were evaluated for association with time to fracture. Forty-six dogs met inclusion criteria. The median overall survival time was 9.7 months (95% CI: 6.9-14.3 months). The fracture-free rates at 3, 6, and 9 months were 73%, 44%, and 38% (95% CI: 60-86%, 29-60%, and 22-54%), respectively. The region of bone affected was significantly associated with time to fracture. The median time to fracture was 4.2 months in dogs with subchondral bone involvement and 16.3 months in dogs without subchondral bone involvement (P-value = 0.027, log-rank test). Acute and late skin effects were present in 58% and 16% of patients, respectively. Findings demonstrated a need for improved patient selection for this procedure, which can be aided by CT-based prognostic factors to predict the likelihood of fracture. © 2016 American College of Veterinary Radiology.

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.

Hypopituitarism after stereotactic radiosurgery for pituitary adenomas.

PubMed

Xu, Zhiyuan; Lee Vance, Mary; Schlesinger, David; Sheehan, Jason P

2013-04-01

Studies of new-onset Gamma Knife stereotactic radiosurgery (SRS)-induced hypopituitarism in large cohort of pituitary adenoma patients with long-term follow-up are lacking. We investigated the outcomes of SRS for pituitary adenoma patients with regard to newly developed hypopituitarism. This was a retrospective review of patients treated with SRS at the University of Virginia between 1994 and 2006. A total of 262 patients with a pituitary adenoma treated with SRS were reviewed. Thorough endocrine assessment was performed immediately before SRS and in regular follow-ups. Assessment consisted of 24-hour urine free cortisol (patients with Cushing disease), serum adrenocorticotropic hormone, cortisol, follicle-stimulating hormone, luteinizing hormone, insulin-like growth factor-1, growth hormone, testosterone (men), prolactin, thyroid-stimulating hormone, and free T(4). Endocrine remission occurred in 144 of 199 patients with a functioning adenoma. Tumor control rate was 89%. Eighty patients experienced at least 1 axis of new-onset SRS-induced hypopituitarism. The new hypopituitarism rate was 30% based on endocrine follow-up ranging from 6 to 150 months; the actuarial rate of new pituitary hormone deficiency was 31.5% at 5 years after SRS. On univariate and multivariate analyses, variables regarding the increased risk of hypopituitarism included suprasellar extension and higher radiation dose to the tumor margin; there were no correlations among tumor volume, prior transsphenoidal adenomectomy, prior radiation therapy, and age at SRS. SRS provides an effective and safe treatment option for patients with a pituitary adenoma. Higher margin radiation dose to the adenoma and suprasellar extension were 2 independent predictors of SRS-induced hypopituitarism.

Technical Note: Dose gradients and prescription isodose in orthovoltage stereotactic radiosurgery

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

Fagerstrom, Jessica M., E-mail: fagerstrom@wisc.edu; Bender, Edward T.; Culberson, Wesley S.

Purpose: The purpose of this work is to examine the trade-off between prescription isodose and dose gradients in orthovoltage stereotactic radiosurgery. Methods: Point energy deposition kernels (EDKs) describing photon and electron transport were calculated using Monte Carlo methods. EDKs were generated from 10  to 250 keV, in 10 keV increments. The EDKs were converted to pencil beam kernels and used to calculate dose profiles through isocenter from a 4π isotropic delivery from all angles of circularly collimated beams. Monoenergetic beams and an orthovoltage polyenergetic spectrum were analyzed. The dose gradient index (DGI) is the ratio of the 50% prescription isodosemore » volume to the 100% prescription isodose volume and represents a metric by which dose gradients in stereotactic radiosurgery (SRS) may be evaluated. Results: Using the 4π dose profiles calculated using pencil beam kernels, the relationship between DGI and prescription isodose was examined for circular cones ranging from 4 to 18 mm in diameter and monoenergetic photon beams with energies ranging from 20 to 250 keV. Values were found to exist for prescription isodose that optimize DGI. Conclusions: The relationship between DGI and prescription isodose was found to be dependent on both field size and energy. Examining this trade-off is an important consideration for designing optimal SRS systems.« less

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

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

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

Dieterich, S.

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

Cranial Stereotactic Radiosurgery: Current Status of the Initial Paradigm Shifter

PubMed Central

Sheehan, Jason P.; Yen, Chun-Po; Lee, Cheng-Chia; Loeffler, Jay S.

2014-01-01

The concept of stereotactic radiosurgery (SRS) was first described by Lars Leksell in 1951. It was proposed as a noninvasive alternative to open neurosurgical approaches to manage a variety of conditions. In the following decades, SRS emerged as a unique discipline involving a collegial partnership among neurosurgeons, radiation oncologists, and medical physicists. SRS relies on the precisely guided delivery of high-dose ionizing radiation to an intracranial target. The focused convergence of multiple beams yields a potent therapeutic effect on the target and a steep dose fall-off to surrounding structures, thereby minimizing the risk of collateral damage. SRS is typically administered in a single session but can be given in as many as five sessions or fractions. By providing an ablative effect noninvasively, SRS has altered the treatment paradigms for benign and malignant intracranial tumors, functional disorders, and vascular malformations. Literature on extensive intracranial radiosurgery has unequivocally demonstrated the favorable benefit-to-risk profile that SRS affords for appropriately selected patients. In a departure from conventional radiotherapeutic strategies, radiosurgical principles have recently been extended to extracranial indications such as lung, spine, and liver tumors. The paradigm shift resulting from radiosurgery continues to alter the landscape of related fields. PMID:25113762

Cranial stereotactic radiosurgery: current status of the initial paradigm shifter.

PubMed

Sheehan, Jason P; Yen, Chun-Po; Lee, Cheng-Chia; Loeffler, Jay S

2014-09-10

The concept of stereotactic radiosurgery (SRS) was first described by Lars Leksell in 1951. It was proposed as a noninvasive alternative to open neurosurgical approaches to manage a variety of conditions. In the following decades, SRS emerged as a unique discipline involving a collegial partnership among neurosurgeons, radiation oncologists, and medical physicists. SRS relies on the precisely guided delivery of high-dose ionizing radiation to an intracranial target. The focused convergence of multiple beams yields a potent therapeutic effect on the target and a steep dose fall-off to surrounding structures, thereby minimizing the risk of collateral damage. SRS is typically administered in a single session but can be given in as many as five sessions or fractions. By providing an ablative effect noninvasively, SRS has altered the treatment paradigms for benign and malignant intracranial tumors, functional disorders, and vascular malformations. Literature on extensive intracranial radiosurgery has unequivocally demonstrated the favorable benefit-to-risk profile that SRS affords for appropriately selected patients. In a departure from conventional radiotherapeutic strategies, radiosurgical principles have recently been extended to extracranial indications such as lung, spine, and liver tumors. The paradigm shift resulting from radiosurgery continues to alter the landscape of related fields. © 2014 by American Society of Clinical Oncology.

Stereotactic radiosurgery for the treatment of symptomatic brainstem cavernous malformations.

PubMed

Monaco, Edward A; Khan, Aftab A; Niranjan, Ajay; Kano, Hideyuki; Grandhi, Ramesh; Kondziolka, Douglas; Flickinger, John C; Lunsford, L Dade

2010-09-01

The authors performed a retrospective review of prospectively collected data to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) for the treatment of patients harboring symptomatic solitary cavernous malformations (CMs) of the brainstem that bleed repeatedly and are high risk for resection. Between 1988 and 2005, 68 patients (34 males and 34 females) with solitary, symptomatic CMs of the brainstem underwent Gamma Knife surgery. The mean patient age was 41.2 years, and all patients had suffered at least 2 symptomatic hemorrhages (range 2-12 events) before radiosurgery. Prior to SRS, 15 patients (22.1%) had undergone attempted resection. The mean volume of the malformation treated was 1.19 ml, and the mean prescribed marginal radiation dose was 16 Gy. The mean follow-up period was 5.2 years (range 0.6-12.4 years). The pre-SRS annual hemorrhage rate was 32.38%, or 125 hemorrhages, excluding the first hemorrhage, over a total of 386 patient-years. Following SRS, 11 hemorrhages were observed within the first 2 years of follow-up (8.22% annual hemorrhage rate) and 3 hemorrhages were observed in the period after the first 2 years of follow-up (1.37% annual hemorrhage rate). A significant reduction (p < 0.0001) in the risk of brainstem CM hemorrhages was observed following radiosurgical treatment, as well as in latency period of 2 years after SRS (p < 0.0447). Eight patients (11.8%) experienced new neurological deficits as a result of adverse radiation effects following SRS. The results of this study support a role for the use of SRS for symptomatic CMs of the brainstem, as it is relatively safe and appears to reduce rebleeding rates in this high-surgical-risk location.

Results of stereotactic radiosurgery for patients with imaging defined cavernous sinus meningiomas

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

Pollock, Bruce E.; Stafford, Scott L.

2005-08-01

Introduction: The purpose of this study was to evaluate the efficacy and safety of stereotactic radiosurgery as primary management for patients with imaging defined cavernous sinus meningiomas. Methods: Between 1992 and 2001, 49 patients had radiosurgery for dural-based masses of the cavernous sinus presumed to be meningiomas. The mean patient age was 55.5 years. The mean tumor volume was 10.2 mL; the mean tumor margin dose was 15.9 Gy. The mean follow-up was 58 months (range, 16-144 months). Results: No tumor enlarged after radiosurgery. Twelve of 38 patients (26%) with preexisting diplopia or facial numbness/pain had improvement in cranial nervemore » function. Five patients (10%) had new (n = 3) or worsened (n = 2) trigeminal dysfunction; 2 of these patients (4%) underwent surgery at 20 and 25 months after radiosurgery despite no evidence of tumor progression. Neither patient improved after partial tumor resection. One patient (2%) developed an oculomotor nerve injury. One patient (2%) had an ischemic stroke related to occlusion of the cavernous segment of the internal carotid artery. Event-free survival was 98%, 85%, and 80% at 1, 3, and 7 years after radiosurgery, respectively. Univariate analysis of patient and dosimetric factors found no analyzed factor correlated with postradiosurgical morbidity. Conclusions: Radiosurgery was an effective primary management strategy for patients with an imaging defined cavernous sinus meningioma. Except in situations of symptomatic mass effect, unusual clinical presentation, or atypical imaging features, surgery to confirm the histologic diagnosis is unlikely to provide clinical benefit.« less

Inception of a national multidisciplinary registry for stereotactic radiosurgery.

PubMed

Sheehan, Jason P; Kavanagh, Brian D; Asher, Anthony; Harbaugh, Robert E

2016-01-01

Stereotactic radiosurgery (SRS) represents a multidisciplinary approach to the delivery of ionizing high-dose radiation to treat a wide variety of disorders. Much of the radiosurgical literature is based upon retrospective single-center studies along with a few randomized controlled clinical trials. More timely and effective evidence is needed to enhance the consistency and quality of and clinical outcomes achieved with SRS. The authors summarize the creation and implementation of a national SRS registry. The American Association of Neurological Surgeons (AANS) through NeuroPoint Alliance, Inc., started a successful registry effort with its lumbar spine initiative. Following a similar approach, the AANS and NeuroPoint Alliance collaborated with corporate partners and the American Society for Radiation Oncology to devise a data dictionary for an SRS registry. Through administrative and financial support from professional societies and corporate partners, a framework for implementation of the registry was created. Initial plans were devised for a 3-year effort encompassing 30 high-volume SRS centers across the country. Device-specific web-based data-extraction platforms were built by the corporate partners. Data uploaders were then used to port the data to a common repository managed by Quintiles, a national and international health care trials company. Audits of the data for completeness and veracity will be undertaken by Quintiles to ensure data fidelity. Data governance and analysis are overseen by an SRS board comprising equal numbers of representatives from the AANS and NeuroPoint Alliance. Over time, quality outcome assessments and post hoc research can be performed to advance the field of SRS. Stereotactic radiosurgery offers a high-technology approach to treating complex intracranial disorders. Improvements in the consistency and quality of care delivered to patients who undergo SRS should be afforded by the national registry effort that is underway.

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.

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

Improvement of radiological penumbra using intermediate energy photons (IEP) for stereotactic radiosurgery.

PubMed

O'Malley, Lauren; Pignol, Jean-Philippe; Beachey, David J; Keller, Brian M; Presutti, Joseph; Sharpe, Michael

2006-05-21

Using efficient immobilization and dedicated beam collimation devices, stereotactic radiosurgery ensures highly conformal treatment of small tumours with limited microscopic extension. One contribution to normal tissue irradiation remains the radiological penumbra. This work aims at demonstrating that intermediate energy photons (IEP), above orthovoltage but below megavoltage, improve dose distribution for stereotactic radiosurgery for small irradiation field sizes due to a dramatic reduction of radiological penumbra. Two different simulation systems were used: (i) Monte Carlo simulation to investigate the dose distribution of monoenergetic IEP between 100 keV and 1 MeV in water phantom; (ii) the Pinnacle3 TPS including a virtual IEP unit to investigate the dosimetry benefit of treating with 11 non-coplanar beams a 2 cm tumour in the middle of a brain adjacent to a 1 mm critical structure. Radiological penumbrae below 300 microm are generated for field size below 2 x 2 cm2 using monoenergetic IEP beams between 200 and 400 keV. An 800 kV beam generated in a 0.5 mm tungsten target maximizes the photon intensity in this range. Pinnacle3 confirms the dramatic reduction in penumbra size. DVHs show for a constant dose distribution conformality, improved dose distribution homogeneity and better sparing of critical structures using a 800 kV beam compared to a 6 MV beam.

Improvement of radiological penumbra using intermediate energy photons (IEP) for stereotactic radiosurgery

NASA Astrophysics Data System (ADS)

O'Malley, Lauren; Pignol, Jean-Philippe; Beachey, David J.; Keller, Brian M.; Presutti, Joseph; Sharpe, Michael

2006-05-01

Using efficient immobilization and dedicated beam collimation devices, stereotactic radiosurgery ensures highly conformal treatment of small tumours with limited microscopic extension. One contribution to normal tissue irradiation remains the radiological penumbra. This work aims at demonstrating that intermediate energy photons (IEP), above orthovoltage but below megavoltage, improve dose distribution for stereotactic radiosurgery for small irradiation field sizes due to a dramatic reduction of radiological penumbra. Two different simulation systems were used: (i) Monte Carlo simulation to investigate the dose distribution of monoenergetic IEP between 100 keV and 1 MeV in water phantom; (ii) the Pinnacle3 TPS including a virtual IEP unit to investigate the dosimetry benefit of treating with 11 non-coplanar beams a 2 cm tumour in the middle of a brain adjacent to a 1 mm critical structure. Radiological penumbrae below 300 µm are generated for field size below 2 × 2 cm2 using monoenergetic IEP beams between 200 and 400 keV. An 800 kV beam generated in a 0.5 mm tungsten target maximizes the photon intensity in this range. Pinnacle3 confirms the dramatic reduction in penumbra size. DVHs show for a constant dose distribution conformality, improved dose distribution homogeneity and better sparing of critical structures using a 800 kV beam compared to a 6 MV beam.

Stereotactic Radiosurgery and Fractionated Stereotactic Radiation Therapy for the Treatment of Uveal Melanoma

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

Yazici, Gozde; Kiratli, Hayyam; Ozyigit, Gokhan

Purpose: To evaluate treatment results of stereotactic radiosurgery or fractionated stereotactic radiation therapy (SRS/FSRT) for uveal melanoma. Methods and Materials: We retrospectively evaluated 181 patients with 182 uveal melanomas receiving SRS/FSRT between 2007 and 2013. Treatment was administered with CyberKnife. Results: According to Collaborative Ocular Melanoma Study criteria, tumor size was small in 1%, medium in 49.5%, and large in 49.5% of the patients. Seventy-one tumors received <45 Gy, and 111 received ≥45 Gy. Median follow-up time was 24 months. Complete and partial response was observed in 8 and 104 eyes, respectively. The rate of 5-year overall survival was 98%, disease-free survival 57%,more » local recurrence-free survival 73%, distant metastasis-free survival 69%, and enucleation-free survival 73%. There was a significant correlation between tumor size and disease-free survival, SRS/FSRT dose and enucleation-free survival; and both were prognostic for local recurrence-free survival. Enucleation was performed in 41 eyes owing to progression in 26 and complications in 11. Conclusions: The radiation therapy dose is of great importance for local control and eye retention; the best treatment outcome was achieved using ≥45 Gy in 3 fractions.« less

International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

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

Cox, Brett W., E-mail: coxb@mskcc.org; Spratt, Daniel E.; Lovelock, Michael

2012-08-01

Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE)more » with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive

A New Predictive Tool for Optimization of the Treatment of Brain Metastases from Colorectal Cancer After Stereotactic Radiosurgery.

PubMed

Rades, Dirk; Dahlke, Markus; Gebauer, Niklas; Bartscht, Tobias; Hornung, Dagmar; Trang, Ngo Thuy; Phuong, Pham Cam; Khoa, Mai Trong; Gliemroth, Jan

2015-10-01

To develop a predictive tool for survival after stereotactic radiosurgery of brain metastases from colorectal cancer. Out of nine factors analyzed for survival, those showing significance (p<0.05) or a trend (p≤0.06) were included. For each factor, 0 (worse survival) or 1 (better survival) point was assigned. Total scores represented the sum of the factor scores. Performance status (p=0.010) and interval from diagnosis of colorectal cancer until radiosurgery (p=0.026) achieved significance, extracranial metastases showed a trend (p=0.06). These factors were included in the tool. Total scores were 0-3 points. Six-month survival rates were 17% for patients with 0, 25% for those with 1, 67% for those with 2 and 100% for those with 3 points; 12-month rates were 0%, 0%, 33% and 67%, respectively. Two groups were created: 0-1 and 2-3 points. Six- and 12-month survival rates were 20% vs. 78% and 0% vs. 44% (p=0.002), respectively. This tool helps optimize the treatment of patients after stereotactic radiosurgery for brain metastases from colorectal cancer. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Stereotactic radiosurgery vs. fractionated radiotherapy for tumor control in vestibular schwannoma patients: a systematic review.

PubMed

Persson, Oscar; Bartek, Jiri; Shalom, Netanel Ben; Wangerid, Theresa; Jakola, Asgeir Store; Förander, Petter

2017-06-01

Repeated controlled studies have revealed that stereotactic radiosurgery is better than microsurgery for patients with vestibular schwannoma (VS) <3 cm in need of intervention. In this systematic review we aimed to compare results from single-fraction stereotactic radiosurgery (SRS) to fractionated stereotactic radiotherapy (FSRT) for patients with VS. We systematically searched MEDLINE, Web of Science, Embase and Cochrane and screened relevant articles for references. Publications from 1995 through 2014 with a minimum of 50 adult (>18 years) patients with unilateral VS, followed for a median of >5 years, were eligible for inclusion. After screening titles and abstracts of the 1094 identified articles and systematically reviewing 98 of these articles, 19 were included. Patients with unilateral VS treated with radiosurgery were compared to patients treated with fractionated stereotactic radiotherapy. No randomized controlled trial (RCT) was identified. None of the identified controlled studies comparing SRS with FSRT were eligible according to the inclusion criteria. Nineteen case series on SRS (n = 17) and FSRT (n = 2) were included in the systematic review. Loss of tumor control necessitating a new VS-targeted intervention was found in an average of 5.0% of the patients treated with SRS and in 4.8% treated with FSRT. Mean deterioration ratio for patients with serviceable hearing before treatment was 49% for SRS and 45% for FSRT, respectively. The risk for facial nerve deterioration was 3.6% for SRS and 11.2% for FSRT and for trigeminal nerve deterioration 6.0% for SRS and 8.4% for FSRT. Since these results were obtained from case series, a regular meta-analysis was not attempted. SRS and FSRT are both noninvasive treatment alternatives for patients with VS with low rates of treatment failure in need of rescue therapy. In this selection of patients, the progression-free survival rates were on the order of 92-100% for both treatment options. There is a lack

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.

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.

Pathological characteristics of spine metastases treated with high-dose single-fraction stereotactic radiosurgery.

PubMed

Katsoulakis, Evangelia; Laufer, Ilya; Bilsky, Mark; Agaram, Narasimhan P; Lovelock, Michael; Yamada, Yoshiya

2017-01-01

OBJECTIVE Spine radiosurgery is increasingly being used to treat spinal metastases. As patients are living longer because of the increasing efficacy of systemic agents, appropriate follow-up and posttreatment management for these patients is critical. Tumor progression after spine radiosurgery is rare; however, vertebral compression fractures are recognized as a more common posttreatment effect. The use of radiographic imaging alone posttreatment may makeit difficult to distinguish tumor progression from postradiation changes such as fibrosis. This is the largest series from a prospective database in which the authors examine histopathology of samples obtained from patients who underwent surgical intervention for presumed tumor progression or mechanical pain secondary to compression fracture. The majority of patients had tumor ablation and resulting fibrosis rather than tumor progression. The aim of this study was to evaluate tumor histopathology and characteristics of patients who underwent pathological sampling because of radiographic tumor progression, fibrosis, or collapsed vertebrae after receiving high-dose single-fraction stereotactic radiosurgery. METHODS Between January 2005 and January 2014, a total of 582 patients were treated with linear accelerator-based single-fraction (18-24 Gy) stereotactic radiosurgery. The authors retrospectively identified 30 patients (5.1%) who underwent surgical intervention for 32 lesions with vertebral cement augmentation for either mechanical pain or instability secondary to vertebral compression fracture (n = 17) or instrumentation (n = 15) for radiographic tumor progression. Radiation and surgical treatment, histopathology, and long-term outcomes were reviewed. Survival and time to recurrence were calculated using the Kaplan-Meier method. RESULTS The mean age at the time of radiosurgery was 59 years (range 36-80 years). The initial pathological diagnoses were obtained for all patients and primarily included radioresistant

Pathological characteristics of spine metastases treated with high-dose single-fraction stereotactic radiosurgery

PubMed Central

Katsoulakis, Evangelia; Laufer, Ilya; Bilsky, Mark; Agaram, Narasimhan P.; Lovelock, Michael; Yamada, Yoshiya

2017-01-01

OBJECTIVE Spine radiosurgery is increasingly being used to treat spinal metastases. As patients are living longer because of the increasing efficacy of systemic agents, appropriate follow-up and posttreatment management for these patients is critical. Tumor progression after spine radiosurgery is rare; however, vertebral compression fractures are recognized as a more common posttreatment effect. The use of radiographic imaging alone posttreatment may make it difficult to distinguish tumor progression from postradiation changes such as fibrosis. This is the largest series from a prospective database in which the authors examine histopathology of samples obtained from patients who underwent surgical intervention for presumed tumor progression or mechanical pain secondary to compression fracture. The majority of patients had tumor ablation and resulting fibrosis rather than tumor progression. The aim of this study was to evaluate tumor histopathology and characteristics of patients who underwent pathological sampling because of radiographic tumor progression, fibrosis, or collapsed vertebrae after receiving high-dose single-fraction stereotactic radiosurgery. METHODS Between January 2005 and January 2014, a total of 582 patients were treated with linear accelerator–based single-fraction (18–24 Gy) stereotactic radiosurgery. The authors retrospectively identified 30 patients (5.1%) who underwent surgical intervention for 32 lesions with vertebral cement augmentation for either mechanical pain or instability secondary to vertebral compression fracture (n = 17) or instrumentation (n = 15) for radiographic tumor progression. Radiation and surgical treatment, histopathology, and long-term outcomes were reviewed. Survival and time to recurrence were calculated using the Kaplan-Meier method. RESULTS The mean age at the time of radiosurgery was 59 years (range 36–80 years). The initial pathological diagnoses were obtained for all patients and primarily included

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

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.

Resection followed by stereotactic radiosurgery to resection cavity for intracranial metastases.

PubMed

Do, Ly; Pezner, Richard; Radany, Eric; Liu, An; Staud, Cecil; Badie, Benham

2009-02-01

In patients who undergo resection of central nervous system metastases, whole brain radiotherapy (WBRT) is added to reduce the rates of recurrence and neurologic death. However, the risk of late neurotoxicity has led many patients to decline WBRT. We offered adjuvant stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) as an alternative to select patients with resected brain metastases. We performed a retrospective review of patients who underwent brain metastasis resection followed by SRS/SRT. WBRT was administered only as salvage treatment. Patients had one to four brain metastases. The dose was 15-18 Gy for SRS and 22-27.5 Gy in four to six fractions for SRT. Target margins were typically expanded by 1 mm for rigid immobilization and 3 mm for mask immobilization. SRS/SRT involved the use of linear accelerator radiosurgery using the IMRT 21EX or Helical Tomotherapy unit. Between December 1999 and January 2007, 30 patients diagnosed with intracranial metastases were treated with resection followed by SRS or SRT to the resection cavity. Of the 30 patients, 4 (13.3%) developed recurrence in the resection cavity, and 19 (63%) developed recurrences in new intracranial sites. The actuarial 12-month survival rate was 82% for local recurrence-free survival, 31% for freedom from new brain metastases, 67% for neurologic deficit-free survival, and 51% for overall survival. Salvage WBRT was performed in 14 (47%) of the 30 patients. Our results suggest that for patients with newly diagnosed brain metastases treated with surgical resection, postoperative SRS/SRT to the resection cavity is a feasible option. WBRT can be reserved as salvage treatment with acceptable neurologic deficit-free survival.

Stereotactic Radiosurgery for Intracranial Ependymomas: An International Multicenter Study.

PubMed

Kano, Hideyuki; Su, Yan-Hua; Wu, Hsiu-Mei; Simonova, Gabriela; Liscak, Roman; Cohen-Inbar, Or; Sheehan, Jason P; Meola, Antonio; Sharma, Mayur; Barnett, Gene H; Mathieu, David; Vasas, Lucas T; Kaufmann, Anthony M; Jacobs, Rachel C; Lunsford, L Dade

2018-03-28

Stereotactic radiosurgery (SRS) is a potentially important option for intracranial ependymoma patients. To analyze the outcomes of intracranial ependymoma patients who underwent SRS as a part of multimodality management. Seven centers participating in the International Gamma Knife Research Foundation identified 89 intracranial ependymoma patients who underwent SRS (113 tumors). The median patient age was 16.3 yr (2.9-80). All patients underwent previous surgical resection and radiation therapy (RT) of their ependymomas and 40 underwent previous chemotherapy. Grade 2 ependymomas were present in 42 patients (52 tumors) and grade 3 ependymomas in 48 patients (61 tumors). The median tumor volume was 2.2 cc (0.03-36.8) and the median margin dose was 15 Gy (9-24). Forty-seven (53%) patients were alive and 42 (47%) patients died at the last follow-up. The overall survival after SRS was 86% at 1 yr, 50% at 3 yr, and 44% at 5 yr. Smaller total tumor volume was associated with longer overall survival (P = .006). Twenty-two patients (grade 2: n = 9, grade 3: n = 13) developed additional recurrent ependymomas in the craniospinal axis. The progression-free survival after SRS was 71% at 1 yr, 56% at 3 yr, and 48% at 5 yr. Adult age, female sex, and smaller tumor volume indicated significantly better progression-free survival. Symptomatic adverse radiation effects were seen in 7 patients (8%). SRS provides another management option for residual or recurrent progressive intracranial ependymoma patients who have failed initial surgery and RT.

Gold nanoparticle enhancement of stereotactic radiosurgery for neovascular age-related macular degeneration

NASA Astrophysics Data System (ADS)

Ngwa, Wilfred; Makrigiorgos, G. Mike; Berbeco, Ross I.

2012-10-01

Age-related macular degeneration (AMD) is the leading cause of blindness in developed countries for people over the age of 50. In this work, the dosimetric feasibility of using gold nanoparticles (AuNP) as radiosensitizers to enhance kilovoltage stereotactic radiosurgery for neovascular AMD is investigated. Microdosimetry calculations at the sub-cellular level were carried out to estimate the radiation dose enhancement to individual nuclei in neovascular AMD endothelial cells (nDEF) due to photon-induced photo-/Auger electrons from x-ray-irradiated AuNP. The nDEF represents the ratio of radiation doses to the endothelial cell nuclei with and without AuNP. The calculations were carried out for a range of feasible AuNP local concentrations using the clinically applicable 100 kVp x-ray beam parameters employed by a commercially available x-ray therapy system. The results revealed nDEF values of 1.30-3.26 for the investigated concentration range of 1-7 mg g-1, respectively. In comparison, for the same concentration range, nDEF values of 1.32-3.40, 1.31-3.33, 1.29-3.19, 1.28-3.12 were calculated for 80, 90, 110 and 120 kVp x-rays, respectively. Meanwhile, calculations as a function of distance from the AuNP showed that the dose enhancement, for 100 kVp, is markedly confined to the targeted neovascular AMD endothelial cells where AuNP are localized. These findings provide impetus for considering the application of AuNP to enhance therapeutic efficacy during stereotactic radiosurgery for neovascular AMD.

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

International multicenter cohort study of pediatric brain arteriovenous malformations. Part 2: Outcomes after stereotactic radiosurgery.

PubMed

Starke, Robert M; Ding, Dale; Kano, Hideyuki; Mathieu, David; Huang, Paul P; Feliciano, Caleb; Rodriguez-Mercado, Rafael; Almodovar, Luis; Grills, Inga S; Silva, Danilo; Abbassy, Mahmoud; Missios, Symeon; Kondziolka, Douglas; Barnett, Gene H; Dade Lunsford, L; Sheehan, Jason P

2017-02-01

OBJECTIVE Pediatric patients (age < 18 years) harboring brain arteriovenous malformations (AVMs) are burdened with a considerably higher cumulative lifetime risk of hemorrhage than adults. Additionally, the pediatric population was excluded from recent prospective comparisons of intervention versus conservative management for unruptured AVMs. The aims of this multicenter, retrospective cohort study are to analyze the outcomes after stereotactic radiosurgery for unruptured and ruptured pediatric AVMs. METHODS We analyzed and pooled AVM radiosurgery data from 7 participating in the International Gamma Knife Research Foundation. Patients younger than 18 years of age who had at least 12 months of follow-up were included in the study cohort. Favorable outcome was defined as AVM obliteration, no post-radiosurgical hemorrhage, and no permanently symptomatic radiation-induced changes (RIC). The post-radiosurgery outcomes of unruptured versus ruptured pediatric AVMs were compared, and statistical analyses were performed to identify predictive factors. RESULTS The overall pediatric AVM cohort comprised 357 patients with a mean age of 12.6 years (range 2.8-17.9 years). AVMs were previously treated with embolization, resection, and fractionated external beam radiation therapy in 22%, 6%, and 13% of patients, respectively. The mean nidus volume was 3.5 cm 3 , 77% of AVMs were located in eloquent brain areas, and the Spetzler-Martin grade was III or higher in 59%. The mean radiosurgical margin dose was 21 Gy (range 5-35 Gy), and the mean follow-up was 92 months (range 12-266 months). AVM obliteration was achieved in 63%. During a cumulative latency period of 2748 years, the annual post-radiosurgery hemorrhage rate was 1.4%. Symptomatic and permanent radiation-induced changes occurred in 8% and 3%, respectively. Favorable outcome was achieved in 59%. In the multivariate logistic regression analysis, the absence of prior AVM embolization (p = 0.001) and higher margin dose (p < 0

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

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.

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

Peritumoral Brain Edema after Stereotactic Radiosurgery for Asymptomatic Intracranial Meningiomas: Risks and Pattern of Evolution.

PubMed

Hoe, Yeon; Choi, Young Jae; Kim, Jeong Hoon; Kwon, Do Hoon; Kim, Chang Jin; Cho, Young Hyun

2015-10-01

To investigate the risks and pattern of evolution of peritumoral brain edema (PTE) after stereotactic radiosurgery (SRS) for asymptomatic intracranial meningiomas. A retrospective study was conducted on 320 patients (median age 56 years, range 24-87 years) who underwent primary Gamma Knife radiosurgery for asymptomatic meningiomas between 1998 and 2012. The median tumor volume was 2.7 cc (range 0.2-10.5 cc) and the median follow-up was 48 months (range 24-168 months). Volumetric data sets for tumors and PTE on serial MRIs were analyzed. The edema index (EI) was defined as the ratio of the volume of PTE including tumor to the tumor volume, and the relative edema indices (rEIs) were calculated from serial EIs normalized against the baseline EI. Risk factors for PTE were analyzed using logistic regression. Newly developed or increased PTE was noted in 49 patients (15.3%), among whom it was symptomatic in 28 patients (8.8%). Tumor volume larger than 4.2 cc (p<0.001), hemispheric tumor location (p=0.005), and pre-treatment PTE (p<0.001) were associated with an increased risk of PTE. rEI reached its maximum value at 11 months after SRS and decreased thereafter, and symptoms resolved within 24 months in most patients (85.7%). Caution should be exercised in decision-making on SRS for asymptomatic meningiomas of large volume (>4.2 cc), of hemispheric location, or with pre-treatment PTE. PTE usually develops within months, reaches its maximum degree until a year, and resolves within 2 years after SRS.

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

Silent Corticotroph Adenomas After Stereotactic Radiosurgery: A Case–Control Study

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

Xu, Zhiyuan; Ellis, Scott; Lee, Cheng-Chia

Purpose: To investigate the safety and effectiveness of stereotactic radiosurgery (SRS) in patients with a silent corticotroph adenoma (SCA) compared with patients with other subtypes of non–adrenocorticotropic hormone staining nonfunctioning pituitary adenoma (NFA). Methods and Materials: The clinical features and outcomes of 104 NFA patients treated with SRS in our center between September 1994 and August 2012 were evaluated. Among them, 34 consecutive patients with a confirmatory SCA were identified. A control group of 70 patients with other subtypes of NFA were selected for review based on comparable baseline features, including sex, age at the time of SRS, tumor size, marginmore » radiation dose to the tumor, and duration of follow-up. Results: The median follow-up after SRS was 56 months (range, 6-200 months). No patients with an SCA developed Cushing disease during the follow-up. Tumor control was achieved in 21 of 34 patients (62%) in the SCA group, compared with 65 of 70 patients (93%) in the NFA group. The median progression-free survival (PFS) was 58 months in the SCA group. The actuarial PFS was 73%, 46%, and 31% in the SCA group and was 94%, 87%, and 87% in the NFA group at 3, 5, and 8 years, respectively. Silent corticotroph adenomas treated with a dose of ≥17 Gy exhibited improved PFS. New-onset loss of pituitary function developed in 10 patients (29%) in the SCA group, whereas it occurred in 18 patients (26%) in the NFA group. Eight patients (24%) in the SCA group experienced worsening of a visual field deficit or visual acuity attributed to the tumor progression, as did 6 patients (9%) in the NFA group. Conclusion: Silent corticotroph adenomas exhibited a more aggressive course with a higher progression rate than other subtypes of NFAs. Stereotactic radiosurgery is an important adjuvant treatment for control of tumor growth. Increased radiation dose may lead to improved tumor control in SCA patients.« less

Linear accelerator radiosurgery for arteriovenous malformations: Updated literature review.

PubMed

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

2017-04-01

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

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

PubMed

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

2018-04-23

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

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.

Role of stereotactic radiosurgery with a linear accelerator in treatment of intracranial arteriovenous malformations and tumors in children.

PubMed

Loeffler, J S; Rossitch, E; Siddon, R; Moore, M R; Rockoff, M A; Alexander, E

1990-05-01

Between 1986 and 1988, 16 children were treated for 10 arteriovenous malformations and 6 recurrent intracranial tumors with stereotactic radiation therapy using a modified Clinac 6/100 linear accelerator. The median age of our patients was 10.5 years. For the group with arteriovenous malformation, follow-up ranged from 6 months to 37 months (median was 20 months). No patient bled during the follow-up period. Five of eight patients with follow-up longer than 12 months have achieved complete obliteration of their arteriovenous malformation by angiogram. The four remaining patients who have not achieved a complete obliteration are awaiting their 2-year posttreatment angiogram. The other patient has been treated within the year and have not yet been studied. Five of the six recurrent tumor patients are alive with a median follow-up of 8 months. The remaining patient was controlled locally, but he died of recurrent disease outside the area treated with radiosurgery. The radiographic responses of these patients have included three complete responses, two substantial reductions in tumor volume (greater than 50%) and one stabilization. Despite previous radiotherapy, there have been no significant complications in these patients. We conclude that stereotactic radiation therapy using a standard linear accelerator is an effective and safe technique in the treatment of selected intracranial arteriovenous malformations and tumors in children. In addition, stereotactic radiosurgery may have unique applications in the treatment of localized primary and recurrent pediatric brain tumors.

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.

TU-G-BRD-04: A Round Robin Dosimetry Intercomparison of Gamma Stereotactic Radiosurgery Calibration Protocols

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

Drzymala, R; Alvarez, P; Bednarz, G

2015-06-15

Purpose: The purpose of this multi-institutional study was to compare two new gamma stereotactic radiosurgery (GSRS) dosimetry protocols to existing calibration methods. The ultimate goal was to guide AAPM Task Group 178 in recommending a standard GSRS dosimetry protocol. Methods: Nine centers (ten GSRS units) participated in the study. Each institution made eight sets of dose rate measurements: six with two different ionization chambers in three different 160mm-diameter spherical phantoms (ABS plastic, Solid Water and liquid water), and two using the same ionization chambers with a custom in-air positioning jig. Absolute dose rates were calculated using a newly proposed formalismmore » by the IAEA working group for small and non-standard radiation fields and with a new air-kerma based protocol. The new IAEA protocol requires an in-water ionization chamber calibration and uses previously reported Monte-Carlo generated factors to account for the material composition of the phantom, the type of ionization chamber, and the unique GSRS beam configuration. Results obtained with the new dose calibration protocols were compared to dose rates determined by the AAPM TG-21 and TG-51 protocols, with TG-21 considered as the standard. Results: Averaged over all institutions, ionization chambers and phantoms, the mean dose rate determined with the new IAEA protocol relative to that determined with TG-21 in the ABS phantom was 1.000 with a standard deviation of 0.008. For TG-51, the average ratio was 0.991 with a standard deviation of 0.013, and for the new in-air formalism it was 1.008 with a standard deviation of 0.012. Conclusion: Average results with both of the new protocols agreed with TG-21 to within one standard deviation. TG-51, which does not take into account the unique GSRS beam configuration or phantom material, was not expected to perform as well as the new protocols. The new IAEA protocol showed remarkably good agreement with TG-21. Conflict of Interests: Paula

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.

Treatment of Five or More Brain Metastases With Stereotactic Radiosurgery

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

Hunter, Grant K.; Suh, John H.; Reuther, Alwyn M.

2012-08-01

Purpose: To examine the outcomes of patients with five or more brain metastases treated in a single session with stereotactic radiosurgery (SRS). Methods and Materials: Sixty-four patients with brain metastases treated with SRS to five or more lesions in a single session were reviewed. Primary disease type, number of lesions, Karnofsky performance score (KPS) at SRS, and status of primary and systemic disease at SRS were included. Patients were treated using dosing as defined by Radiation Therapy Oncology Group Protocol 90-05, with adjustments for critical structures. We defined prior whole-brain radiotherapy (WBRT) as WBRT completed >1 month before SRS andmore » concurrent WBRT as WBRT completed within 1 month before or after SRS. Kaplan-Meier estimates and Cox proportional hazard regression were used to determine which patient and treatment factors predicted overall survival (OS). Results: The median OS after SRS was 7.5 months. The median KPS was 80 (range, 60-100). A KPS of {>=}80 significantly influenced OS (median OS, 4.8 months for KPS {<=}70 vs. 8.8 months for KPS {>=}80, p = 0.0097). The number of lesions treated did not significantly influence OS (median OS, 6.6 months for eight or fewer lesions vs. 9.9 months for more than eight, p = nonsignificant). Primary site histology did not significantly influence median OS. On multivariate Cox modeling, KPS and prior WBRT significantly predicted for OS. Whole-brain radiotherapy before SRS compared with concurrent WBRT significantly influenced survival, with a risk ratio of 0.423 (95% confidence interval 0.191-0.936, p = 0.0338). No significant differences were observed when no WBRT was compared with concurrent WBRT or when the no WBRT group was compared with prior WBRT. A KPS of {<=}70 predicted for poorer outcomes, with a risk ratio of 2.164 (95% confidence interval 1.157-4.049, p = 0.0157). Conclusions: Stereotactic radiosurgery to five or more brain lesions is an effective treatment option for patients with

Evaluation of a magnetic resonance guided linear accelerator for stereotactic radiosurgery treatment.

PubMed

Wen, Ning; Kim, Joshua; Doemer, Anthony; Glide-Hurst, Carri; Chetty, Indrin J; Liu, Chang; Laugeman, Eric; Xhaferllari, Ilma; Kumarasiri, Akila; Victoria, James; Bellon, Maria; Kalkanis, Steve; Siddiqui, M Salim; Movsas, Benjamin

2018-06-01

The purpose of this study was to investigate the systematic localization accuracy, treatment planning capability, and delivery accuracy of an integrated magnetic resonance imaging guided Linear Accelerator (MR-Linac) platform for stereotactic radiosurgery. The phantom for the end-to-end test comprises three different compartments: a rectangular MR/CT target phantom, a Winston-Lutz cube, and a rectangular MR/CT isocenter phantom. Hidden target tests were performed at gantry angles of 0, 90, 180, and 270 degrees to quantify the systematic accuracy. Five patient plans with a total of eleven lesions were used to evaluate the dosimetric accuracy. Single-isocenter IMRT treatment plans using 10-15 coplanar beams were generated to treat the multiple metastases. The end-to-end localization accuracy of the system was 1.0 ± 0.1 mm. The conformity index, homogeneity index and gradient index of the plans were 1.26 ± 0.22, 1.22 ± 0.10, and 5.38 ± 1.44, respectively. The average absolute point dose difference between measured and calculated dose was 1.64 ± 1.90%, and the mean percentage of points passing the 3%/1 mm gamma criteria was 96.87%. Our experience demonstrates that excellent plan quality and delivery accuracy was achievable on the MR-Linac for treating multiple brain metastases with a single isocenter. Copyright © 2018 Elsevier B.V. All rights reserved.

Long-term Evaluation of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

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

Leavitt, Jacqueline A., E-mail: leavitt.jacqueline@mayo.edu; Stafford, Scott L.; Link, Michael J.

2013-11-01

Purpose: To determine the long-term risk of radiation-induced optic neuropathy (RION) in patients having single-fraction stereotactic radiosurgery (SRS) for benign skull base tumors. Methods and Materials: Retrospective review of 222 patients having Gamma Knife radiosurgery for benign tumors adjacent to the anterior visual pathway (AVP) between 1991 and 1999. Excluded were patients with prior or concurrent external beam radiation therapy or SRS. One hundred twenty-nine patients (58%) had undergone previous surgery. Tumor types included confirmed World Health Organization grade 1 or presumed cavernous sinus meningioma (n=143), pituitary adenoma (n=72), and craniopharyngioma (n=7). The maximum dose to the AVP was ≤8.0more » Gy (n=126), 8.1-10.0 Gy (n=39), 10.1-12.0 Gy (n=47), and >12 Gy (n=10). Results: The mean clinical and imaging follow-up periods were 83 and 123 months, respectively. One patient (0.5%) who received a maximum radiation dose of 12.8 Gy to the AVP developed unilateral blindness 18 months after SRS. The chance of RION according to the maximum radiation dose received by the AVP was 0 (95% confidence interval [CI] 0-3.6%), 0 (95% CI 0-10.7%), 0 (95% CI 0-9.0%), and 10% (95% CI 0-43.0%) for patients receiving ≤8 Gy, 8.1-10.0 Gy, 10.1-12.0 Gy, and >12 Gy, respectively. The overall risk of RION in patients receiving >8 Gy to the AVP was 1.0% (95% CI 0-6.2%). Conclusions: The risk of RION after single-fraction SRS in patients with benign skull base tumors who have no prior radiation exposure is very low if the maximum dose to the AVP is ≤12 Gy. Physicians performing single-fraction SRS should remain cautious when treating lesions adjacent to the AVP, especially when the maximum dose exceeds 10 Gy.« less

Cost-effectiveness of focused ultrasound, radiosurgery, and DBS for essential tremor.

PubMed

Ravikumar, Vinod K; Parker, Jonathon J; Hornbeck, Traci S; Santini, Veronica E; Pauly, Kim Butts; Wintermark, Max; Ghanouni, Pejman; Stein, Sherman C; Halpern, Casey H

2017-08-01

Essential tremor remains a very common yet medically refractory condition. A recent phase 3 study demonstrated that magnetic resonance-guided focused ultrasound thalamotomy significantly improved upper limb tremor. The objectives of this study were to assess this novel therapy's cost-effectiveness compared with existing procedural options. Literature searches of magnetic resonance-guided focused ultrasound thalamotomy, DBS, and stereotactic radiosurgery for essential tremor were performed. Pre- and postoperative tremor-related disability scores were collected from 32 studies involving 83 magnetic resonance-guided focused ultrasound thalamotomies, 615 DBSs, and 260 stereotactic radiosurgery cases. Utility, defined as quality of life and derived from percent change in functional disability, was calculated; Medicare reimbursement was employed as a proxy for societal cost. Medicare reimbursement rates are not established for magnetic resonance-guided focused ultrasound thalamotomy for essential tremor; therefore, reimbursements were estimated to be approximately equivalent to stereotactic radiosurgery to assess a cost threshold. A decision analysis model was constructed to examine the most cost-effective option for essential tremor, implementing meta-analytic techniques. Magnetic resonance-guided focused ultrasound thalamotomy resulted in significantly higher utility scores compared with DBS (P < 0.001) or stereotactic radiosurgery (P < 0.001). Projected costs of magnetic resonance-guided focused ultrasound thalamotomy were significantly less than DBS (P < 0.001), but not significantly different from radiosurgery. Magnetic resonance-guided focused ultrasound thalamotomy is cost-effective for tremor compared with DBS and stereotactic radiosurgery and more effective than both. Even if longer follow-up finds changes in effectiveness or costs, focused ultrasound thalamotomy will likely remain competitive with both alternatives. © 2017 International Parkinson and Movement

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

Clinical accuracy of ExacTrac intracranial frameless stereotactic system

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

Ackerly, T.; Lancaster, C. M.; Geso, M.

2011-09-15

Purpose: In this paper, the authors assess the accuracy of the Brainlab ExacTrac system for frameless intracranial stereotactic treatments in clinical practice. Methods: They recorded couch angle and image fusion results (comprising lateral, longitudinal, and vertical shifts, and rotation corrections about these axes) for 109 stereotactic radiosurgery and 166 stereotactic radiotherapy patient treatments. Frameless stereotactic treatments involve iterative 6D image fusion corrections applied until the results conform to customizable pass criteria, theirs being 0.7 mm and 0.5 deg. for each axis. The planning CT slice thickness was 1.25 mm. It has been reported in the literature that the CT slices'more » thickness impacts the accuracy of localization to bony anatomy. The principle of invariance with respect to patient orientation was used to determine spatial accuracy. Results: The data for radiosurgery comprised 927 image pairs, of which 532 passed (pass ratio of 57.4%). The data for radiotherapy comprised 15983 image pairs, of which 10 050 passed (pass ratio of 62.9%). For stereotactic radiotherapy, the combined uncertainty of ExacTrac calibration, image fusion, and intrafraction motion was (95% confidence interval) 0.290-0.302 and 0.306-0.319 mm in the longitudinal and lateral axes, respectively. The combined uncertainty of image fusion and intrafraction motion in the anterior-posterior coordinates was 0.174-0.182 mm. For stereotactic radiosurgery, the equivalent ranges are 0.323-0.393, 0.337-0.409, and 0.231-0.281 mm. The overall spatial accuracy was 1.24 mm for stereotactic radiotherapy (SRT) and 1.35 mm for stereotactic radiosurgery (SRS). Conclusions: The ExacTrac intracranial frameless stereotactic system spatial accuracy is adequate for clinical practice, and with the same pass criteria, SRT is more accurate than SRS. They now use frameless stereotaxy exclusively at their center.« less

SU-F-T-587: Quality Assurance of Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiation Therapy (SBRT) for Patient Specific Plans: A Comparison Between MATRIXX and Delta4 QA Devices

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

Tsai, YC; Lu, SH; Chen, LH

2016-06-15

Purpose: Patient-specific quality assurance (QA) is necessary to accurately deliver high dose radiation to the target, especially for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). Unlike previous 2 dimensional (D) array QA devices, Delta{sup 4} can verify the dose delivery in 3D. In this study, the difference between calculated and measured dose distribution was compared with two QA devices (MATRIXX and Delta{sup 4}) to evaluate the delivery accuracy. Methods: Twenty-seven SRS/SBRT plans with VMAT were verified with point-dose and dose-map analysis. We use an ion chamber (A1SL, 0.053cc) for point-dose measurement. For verification of the dose map, themore » differences between the calculated and measured doses were analyzed with a gamma index using MATRIXX and Delta{sup 4} devices. The passing criteria for gamma evaluation were set at 3 mm for distance-to-agreement (DTA) and 3% for dose-difference. A gamma index less than 1 was defined as the verification passing the criteria and satisfying at least 95% of the points. Results: The mean prescribed dose and fraction was 40 ± 14.41 Gy (range: 16–60) and 10 ± 2.35 fractions (range: 1–8), respectively. In point dose analysis, the differences between the calculated and measured doses were all less than 5% (mean: 2.12 ± 1.13%; range: −0.55% to 4.45%). In dose-map analysis, the average passing rates were 99.38 ± 0.96% (range: 95.31–100%) and 100 ± 0.12% (range: 99.5%–100%) for MATRIXX and Delta{sup 4}, respectively. Even using criteria of 2%/2 mm, the passing rate of Delta{sup 4} was still more than 95% (mean: 99 ± 1.08%; range: 95.6%–100%). Conclusion: Both MATRIXX and Delta{sup 4} offer accurate and efficient verification for SRS/SBRT plans. The results measured by MATRIXX and Delta{sup 4} dosimetry systems are similar for SRS/SBRT performed with the VMAT technique.« less

Effect of the embolization material in the dose calculation for stereotactic radiosurgery of arteriovenous malformations

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

Galván de la Cruz, Olga Olinca; Lárraga-Gutiérrez, José Manuel, E-mail: jlarraga@innn.edu.mx; Laboratorio de Física Médica, Instituto Nacional de Neurología y Neurocirugía

2013-07-01

It is reported in the literature that the material used in an embolization of an arteriovenous malformation (AVM) can attenuate the radiation beams used in stereotactic radiosurgery (SRS) up to 10% to 15%. The purpose of this work is to assess the dosimetric impact of this attenuating material in the SRS treatment of embolized AVMs, using Monte Carlo simulations assuming clinical conditions. A commercial Monte Carlo dose calculation engine was used to recalculate the dose distribution of 20 AVMs previously planned with a pencil beam dose calculation algorithm. Dose distributions were compared using the following metrics: average, minimal and maximummore » dose of AVM, and 2D gamma index. The effect in the obliteration rate was investigated using radiobiological models. It was found that the dosimetric impact of the embolization material is less than 1.0 Gy in the prescription dose to the AVM for the 20 cases studied. The impact in the obliteration rate is less than 4.0%. There is reported evidence in the literature that embolized AVMs treated with SRS have low obliteration rates. This work shows that there are dosimetric implications that should be considered in the final treatment decisions for embolized AVMs.« less

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.

Re-irradiation of recurrent anaplastic ependymoma using radiosurgery or fractionated stereotactic radiotherapy.

PubMed

Murai, Taro; Sato, Kengo; Iwabuchi, Michio; Manabe, Yoshihiko; Ogino, Hiroyuki; Iwata, Hiromitsu; Tatewaki, Koshi; Yokota, Naoki; Ohta, Seiji; Shibamoto, Yuta

2016-03-01

Recurrent ependymomas were retreated with stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT). The efficacy, toxicities, and differences between SRS and FSRT were analyzed. Eight patients with recurrent ependymomas fulfilling the criteria described below were evaluated. Inclusion criteria were: (1) the patient had previously undergone surgery and conventional radiotherapy as first-line treatment; (2) targets were located in or adjacent to the eloquent area or were deep-seated; and (3) the previously irradiated volume overlapped the target lesion. FSRT was delivered to 18 lesions, SRS to 20 lesions. A median follow-up period was 23 months. The local control rate was 76 % at 3 years. No significant differences in local control were observed due to tumor size or fractionation schedule. Lesions receiving >25 Gy/5 fr or 21 Gy/3 fr did not recur within 1 year, whereas no dose-response relationship was observed in those treated with SRS. No grade ≥2 toxicity was observed. Our treatment protocol provided an acceptable LC rate and minimal toxicities. Because local recurrence of tumors may result in patient death, a minimum dose of 21 Gy/3 fr or 25 Gy/5 fr or higher may be most suitable for treatment of these cases.

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

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.

SU-F-P-05: Initial Experience with an Independent Certification Program for Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy

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

Solberg, T; Robar, J; Gevaert, T

Purpose: The ASTRO document “Safety is no accident: A FRAMEWORK FOR QUALITY RADIATION ONCOLOGY AND CARE” recommends external reviews of specialized modalities. The purpose of this presentation is to describe the implementation of such a program for Stereotactic Radiosurgery (SRS) and Stereotactic Body radiation Therapy (SBRT). Methods: The margin of error for SRS and SBRT delivery is significantly smaller than that of conventional radiotherapy and therefore requires special attention and diligence. The Novalis Certified program was created to fill an unmet need for specialized SRS / SBRT credentialing. A standards document was drafted by a panel of experts from severalmore » disciplines, including medical physics, radiation oncology and neurosurgery. The document, based on national and international standards, covers requirements in program structure, personnel, training, clinical application, technology, quality management, and patient and equipment QA. The credentialing process was modeled after existing certification programs and includes an institution-generated self-study, extensive document review and an onsite audit. Reviewers generate a descriptive report, which is reviewed by a multidisciplinary expert panel. Outcomes of the review may include mandatory requirements and optional recommendations. Results: 15 institutions have received Novalis Certification, including 3 in the US, 7 in Europe, 4 in Australia and 1 in Asia. 87 other centers are at various stages of the process. Nine reviews have resulted in mandatory requirements, however all of these were addressed within three months of the audit report. All reviews have produced specific recommendations ranging from programmatic to technical in nature. Institutions felt that the credentialing process addressed a critical need and was highly valuable to the institution. Conclusion: Novalis Certification is a unique peer review program assessing safety and quality in SRS and SBRT, while recognizing

Clinical outcomes of patients treated with a second course of stereotactic radiosurgery for locally or regionally recurrent brain metastases after prior stereotactic radiosurgery.

PubMed

Kim, Daniel H; Schultheiss, Timothy E; Radany, Eric H; Badie, Behnam; Pezner, Richard D

2013-10-01

Patients with metastatic disease are living longer and may be confronted with locally or regionally recurrent brain metastases (BM) after prior stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT). This study analyzes outcomes in patients without prior whole brain radiotherapy (WBRT) who were treated with a second course of SRS/FSRT for locally or regionally recurrent BM. We identified 32 patients at our institution who were treated with a second course of SRS/FSRT after initial SRS/FSRT for newly diagnosed BM. We report clinical outcomes including local control, survival, and toxicities. Control rates and survival were calculated using Kaplan-Meier analysis and the multivariate proportional hazards model. The Kaplan-Meier estimate of local control at 6 months was 77 % for targets treated by a second course of SRS/FSRT with 11/71 (15 %) targets experiencing local failure. Multivariate analysis shows that upon re-treatment, local recurrences were more likely to fail than regional recurrences (OR 8.8, p = 0.02). Median survival for all patients from first SRS/FSRT was 14.6 months (5.3-72.2 months) and 7.9 months (0.7-61.1 months) from second SRS/FSRT. Thirty-eight percent of patients ultimately received WBRT as salvage therapy after the second SRS/FSRT. Seventy-one percent of patients died without active neurologic symptoms. The present study demonstrates that the majority of patients who progress after SRS/FSRT for newly diagnosed BM are candidates for salvage SRS/FSRT. By reserving WBRT for later salvage, we believe that a significant proportion of patients can avoid WBRT all together, thus putting fewer patients at risk for neurocognitive toxicity.

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

Assessing the dosimetric and geometric accuracy of stereotactic radiosurgery

NASA Astrophysics Data System (ADS)

Dimitriadis, Alexis

Stereotactic radiosurgery (SRS) is a non-invasive treatment predominantly used for the management of malignant and benign brain tumours. The treatment can be delivered by various platforms in a single fraction where a high dose of radiation is delivered to the target whilst the surrounding healthy tissue is spared. This requires a high degree of accuracy in terms of the dose level delivered but also in terms of geometric precision. The purpose of this work was to identify the variations of SRS practice in the UK and develop a novel method compatible with all practices, capable of assessing the accuracy of delivery. The motivation behind this effort was to contribute to safety in SRS delivery, provide confidence through a quality assurance audit and form a basis to support standardisation in SRS. A national survey was performed to investigate SRS practices in the UK and to help guide the methodology of this thesis. This resulted to the development of a method for an end-to-end audit of SRS. This was based on an anthropomorphic head phantom with a medium sized target located centrally in the brain, in close proximity to the brainstem. This realistic patient scenario was presented to all 26 radiosurgery centres in the UK who were asked to treat it with SRS. The dose delivered was assessed using two novel commercially available radiation detectors, a plastic scintillator and radiochromic film. These detectors were characterised for measuring the dose delivered in SRS. Another established dosimetry system, alanine, was also used alongside these detectors to assess the accuracy of each delivery. The results allowed the assessment of SRS practices in the UK and the comparison of all centres that participated in the audit. The results were also used to evaluate the performance of the dosimeters used for the purposes of quality assurance measurements and audit.

[Transient enlargement of craniopharyngioma cysts after stereotactic radiotherapy and radiosurgery].

PubMed

Mazerkina, N A; Savateev, A N; Gorelyshev, S K; Konovalov, A N; Trunin, Yu Yu; Golanov, A V; Medvedeva, O A; Kalinin, P L; Kutin, M A; Astafieva, L I; Krasnova, T S; Ozerova, V I; Serova, N K; Butenko, E I; Strunina, Yu V

Stereotactic radiotherapy/radiosurgery (RT/ES) is an effective technique for treating craniopharyngiomas (CPs). However, enlargement of the cystic part of the tumor occurs in some cases after irradiation. The enlargement may be transient and not require treatment or be a true relapse requiring treatment. In this study, we performed a retrospective analysis of 79 pediatric patients who underwent stereotactic RT or RS after resection of craniopharyngioma. Five-year relapse-free survival after complex treatment of CP was 86%. In the early period after irradiation, 3.5 months (2.7-9.4) on average, enlargement of the cystic component of the tumor was detected in 10 (12.7%) patients; in 9 (11.4%) of them, the enlargement was transient and did not require treatment; in one case, the patient underwent surgery due to reduced visual acuity. In 8 (10.1%) patients, an increase in the residual tumor (a solid component of the tumor in 2 cases and a cystic component of the tumor in 6 cases) occurred in the long-term period after irradiation - after 26.3 months (16.6-48.9) and did not decrease during follow-up in none of the cases, i.e. continued growth of the tumor was diagnosed. A statistical analysis revealed that differences in the terms of transient enlargement and true continued growth were statistically significant (p<0.01). Enlargement of a craniopharyngioma cyst in the early period (up to 1 year) after RT/RS is usually transient and does not require surgical treatment (except cases where worsening of neurological symptoms occurs, or occlusive hydrocephalus develops).

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

PubMed

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

2010-12-01

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

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.

The acute onset of nausea and vomiting following stereotactic radiosurgery: Correlation with total dose to area postrema

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

Alexander, E. III; Siddon, R.L.; Loeffler, J.S.

1989-07-01

From 1986 to 1988, 44 patients have been treated for tumors or vascular lesions with stereotactic radiosurgery using a modified standard linear accelerator. In seven patients, nausea and vomiting occurred within 6 hours after the completion of radiosurgery. One of these patients with nausea and occasional vomiting pretreatment had exacerbation several hours after treatment, in spite of droperidol and prochlorperazine prophylaxis. Nausea and vomiting in the other six patients was self-limited and was completely resolved by 12 hours from onset. None of these six patients suffered from nausea and vomiting before treatment. This was directly correlated with the total dosemore » to the vomiting center in the floor of the fourth ventricle (area postrema). The median dose to the vomiting center in the seven patients was 618 cGy (range 275-1257). The final patient in the series received 1088 cGy to the area postrema after droperidol and dexamethasone prophylaxis without developing nausea or vomiting. In the remaining 36 patients who received from less than 5 to 184 cGy to area postrema, nausea and vomiting did not occur. We recommend that patients treated with large fractions of radiation by radiosurgery in this area be premedicated appropriately.« less

Optimized Orthovoltage Stereotactic Radiosurgery

NASA Astrophysics Data System (ADS)

Fagerstrom, Jessica M.

Because of its ability to treat intracranial targets effectively and noninvasively, stereotactic radiosurgery (SRS) is a prevalent treatment modality in modern radiation therapy. This work focused on SRS delivering rectangular function dose distributions, which are desirable for some targets such as those with functional tissue included within the target volume. In order to achieve such distributions, this work used fluence modulation and energies lower than those utilized in conventional SRS. In this work, the relationship between prescription isodose and dose gradients was examined for standard, unmodulated orthovoltage SRS dose distributions. Monte Carlo-generated energy deposition kernels were used to calculate 4pi, isocentric dose distributions for a polyenergetic orthovoltage spectrum, as well as monoenergetic orthovoltage beams. The relationship between dose gradients and prescription isodose was found to be field size and energy dependent, and values were found for prescription isodose that optimize dose gradients. Next, a pencil-beam model was used with a Genetic Algorithm search heuristic to optimize the spatial distribution of added tungsten filtration within apertures of cone collimators in a moderately filtered 250 kVp beam. Four cone sizes at three depths were examined with a Monte Carlo model to determine the effects of the optimized modulation compared to open cones, and the simulations found that the optimized cones were able to achieve both improved penumbra and flatness statistics at depth compared to the open cones. Prototypes of the filter designs calculated using mathematical optimization techniques and Monte Carlo simulations were then manufactured and inserted into custom built orthovoltage SRS cone collimators. A positioning system built in-house was used to place the collimator and filter assemblies temporarily in the 250 kVp beam line. Measurements were performed in water using radiochromic film scanned with both a standard white light

10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

10 CFR 35.610 - Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma...

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Safety procedures and instructions for remote afterloader units, teletherapy units, and gamma stereotactic radiosurgery units. 35.610 Section 35.610 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units...

Superior Prognostic Value of Cumulative Intracranial Tumor Volume Relative to Largest Intracranial Tumor Volume for Stereotactic Radiosurgery-Treated Brain Metastasis Patients.

PubMed

Hirshman, Brian R; Wilson, Bayard; Ali, Mir Amaan; Proudfoot, James A; Koiso, Takao; Nagano, Osamu; Carter, Bob S; Serizawa, Toru; Yamamoto, Masaaki; Chen, Clark C

2018-04-01

Two intracranial tumor volume variables have been shown to prognosticate survival of stereotactic-radiosurgery-treated brain metastasis patients: the largest intracranial tumor volume (LITV) and the cumulative intracranial tumor volume (CITV). To determine whether the prognostic value of the Scored Index for Radiosurgery (SIR) model can be improved by replacing one of its components-LITV-with CITV. We compared LITV and CITV in terms of their survival prognostication using a series of multivariable models that included known components of the SIR: age, Karnofsky Performance Score, status of extracranial disease, and the number of brain metastases. Models were compared using established statistical measures, including the net reclassification improvement (NRI > 0) and integrated discrimination improvement (IDI). The analysis was performed in 2 independent cohorts, each consisting of ∼3000 patients. In both cohorts, CITV was shown to be independently predictive of patient survival. Replacement of LITV with CITV in the SIR model improved the model's ability to predict 1-yr survival. In the first cohort, the CITV model showed an NRI > 0 improvement of 0.2574 (95% confidence interval [CI] 0.1890-0.3257) and IDI of 0.0088 (95% CI 0.0057-0.0119) relative to the LITV model. In the second cohort, the CITV model showed a NRI > 0 of 0.2604 (95% CI 0.1796-0.3411) and IDI of 0.0051 (95% CI 0.0029-0.0073) relative to the LITV model. After accounting for covariates within the SIR model, CITV offers superior prognostic value relative to LITV for stereotactic radiosurgery-treated brain metastasis patients.

Stereotactic radiosurgery for focal leptomeningeal disease in patients with brain metastases.

PubMed

Wolf, Amparo; Donahue, Bernadine; Silverman, Joshua S; Chachoua, Abraham; Lee, Jean K; Kondziolka, Douglas

2017-08-01

Leptomeningeal disease (LMD) is well described in patients with brain metastases, presenting symptomatically in approximately 5% of patients. Conventionally, the presence of LMD is an indication for whole brain radiation therapy (WBRT) and not suitable for stereotactic radiosurgery (SRS). The purpose of the study was to evaluate the local control and overall survival of patients who underwent SRS to focal LMD. We reviewed our prospective registry and identified 32 brain metastases patients with LMD, from a total of 465 patients who underwent SRS between 2013 and 2015. Focal LMD was targeted with SRS in 16 patients. The median imaging follow-up time was 7 months. The median volume of LMD was 372 mm 3 and the median margin dose was 16 Gy. Five patients underwent prior WBRT. Histology included non-small cell lung (8), breast (5), melanoma (1), gastrointestinal (1) and ovarian cancer (1). Follow-up MR imaging was available for 14 patients. LMD was stable in 5 and partially regressed in 8 patients at follow-up. One patient had progression of LMD with hemorrhage 5 months after SRS. Seven patients developed distant LMD at a median time of 7 months. The median actuarial overall survival from SRS for LMD was 10.0 months. The 6-month and 1-year actuarial overall survival was 60% and 26% respectively. Six patients underwent WBRT after SRS for focal LMD at a median time of 6 months. Overall, focal LMD may be may be treated successfully with radiosurgery, potentially delaying WBRT in some patients.

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

Salvage whole brain radiotherapy or stereotactic radiosurgery after initial stereotactic radiosurgery for 1-4 brain metastases.

PubMed

Liu, Yufei; Alexander, Brian M; Chen, Yu-Hui; Horvath, Margaret C; Aizer, Ayal A; Claus, Elizabeth B; Dunn, Ian F; Golby, Alexandra J; Johnson, Mark D; Friesen, Scott; Mannarino, Edward G; Wagar, Matthew; Hacker, Fred L; Arvold, Nils D

2015-09-01

Patients with limited brain metastases are often candidates for stereotactic radiosurgery (SRS) or whole brain radiotherapy (WBRT). Among patients who receive SRS, the likelihood and timing of salvage WBRT or SRS remains unclear. We examined rates of salvage WBRT or SRS among 180 patients with 1-4 newly diagnosed brain metastases who received index SRS from 2008-2013. Competing risks multivariable analysis was used to examine factors associated with time to WBRT. Patients had non-small cell lung (53 %), melanoma (23 %), breast (10 %), renal (6 %), or other (8 %) cancers. Median age was 62 years. Patients received index SRS to 1 (60 %), 2 (21 %), 3 (13 %), or 4 (7 %) brain metastases. Median survival after SRS was 9.7 months (range, 0.3-67.6 months). No further brain-directed radiotherapy was delivered after index SRS in 55 % of patients. Twenty-seven percent of patients ever received salvage WBRT, and 30 % ever received salvage SRS; 12 % of patients received both salvage WBRT and salvage SRS. Median time to salvage WBRT or salvage SRS were 5.6 and 6.1 months, respectively. Age ≤60 years (adjusted hazard ratio [AHR] = 2.80; 95 % CI 1.05-7.51; P = 0.04) and controlled/absent extracranial disease (AHR = 6.76; 95 % CI 1.60-28.7; P = 0.01) were associated with shorter time to salvage WBRT. Isolated brain progression caused death in only 11 % of decedents. In summary, most patients with 1-4 brain metastases receiving SRS never require salvage WBRT or SRS, and the remainder do not require salvage treatment for a median of 6 months.

Characteristics of a novel treatment system for linear accelerator–based stereotactic radiosurgery

PubMed Central

Li, Haisen; Song, Kwang; Chin‐Snyder, Karen; Qin, Yujiao; Kim, Jinkoo; Bellon, Maria; Gulam, Misbah; Gardner, Stephen; Doemer, Anthony; Devpura, Suneetha; Gordon, James; Chetty, Indrin; Siddiqui, Farzan; Ajlouni, Munther; Pompa, Robert; Hammoud, Zane; Simoff, Michael; Kalkanis, Steven; Movsas, Benjamin; Siddiqui, M. Salim

2015-01-01

The purpose of this study is to characterize the dosimetric properties and accuracy of a novel treatment platform (Edge radiosurgery system) for localizing and treating patients with frameless, image‐guided stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). Initial measurements of various components of the system, such as a comprehensive assessment of the dosimetric properties of the flattening filter‐free (FFF) beams for both high definition (HD120) MLC and conical cone‐based treatment, positioning accuracy and beam attenuation of a six degree of freedom (6DoF) couch, treatment head leakage test, and integrated end‐to‐end accuracy tests, have been performed. The end‐to‐end test of the system was performed by CT imaging a phantom and registering hidden targets on the treatment couch to determine the localization accuracy of the optical surface monitoring system (OSMS), cone‐beam CT (CBCT), and MV imaging systems, as well as the radiation isocenter targeting accuracy. The deviations between the percent depth‐dose curves acquired on the new linac‐based system (Edge), and the previously published machine with FFF beams (TrueBeam) beyond Dmax were within 1.0% for both energies. The maximum deviation of output factors between the Edge and TrueBeam was 1.6%. The optimized dosimetric leaf gap values, which were fitted using Eclipse dose calculations and measurements based on representative spine radiosurgery plans, were 0.700 mm and 1.000 mm, respectively. For the conical cones, 6X FFF has sharper penumbra ranging from 1.2−1.8 mm (80%‐20%) and 1.9−3.8 mm (90%‐10%) relative to 10X FFF, which has 1.2−2.2 mm and 2.3−5.1 mm, respectively. The relative attenuation measurements of the couch for PA, PA (rails‐in), oblique, oblique (rails‐out), oblique (rails‐in) were: −2.0%, −2.5%, −15.6%, −2.5%, −5.0% for 6X FFF and −1.4%, −1.5%, −12.2%, −2.5%, −5.0% for 10X FFF, respectively, with a slight

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.

Single institution experience treating 104 vestibular schwannomas with fractionated stereotactic radiation therapy or stereotactic radiosurgery.

PubMed

Anderson, Bethany M; Khuntia, Deepak; Bentzen, Søren M; Geye, Heather M; Hayes, Lori L; Kuo, John S; Baskaya, Mustafa K; Badie, Behnam; Basavatia, Amar; Pyle, G Mark; Tomé, Wolfgang A; Mehta, Minesh P

2014-01-01

The pupose of this study is to assess the long-term outcome and toxicity of fractionated stereotactic radiation therapy (FSRT) and stereotactic radiosurgery (SRS) for 100 vestibular schwannomas treated at a single institution. From 1993 to 2007, 104 patients underwent were treated with radiation therapy for vestibular schwannoma. Forty-eight patients received SRS, with a median prescription dose of 12.5 Gy for SRS (range 9.7-16 Gy). For FSRT, two different fraction schedules were employed: a conventional schedule (ConFSRT) of 1.8 Gy per fraction (Gy/F) for 25 or 28 fractions to a total dose of 45 or 50.4 Gy (n = 19); and a once weekly hypofractionated course (HypoFSRT) consisting of 4 Gy/F for 5 fractions to a total dose of 20 Gy (n = 37). Patients treated with FSRT had better baseline hearing, facial, and trigeminal nerve function, and were more likely to have a diagnosis of NF2. The 5-year progression free rate (PFR) was 97.0 after SRS, 90.5% after HypoFSRT, and 100.0% after ConFSRT (p = NS). Univariate analysis demonstrated that NF2 and larger tumor size (greater than the median) correlated with poorer local control, but prior surgical resection did not. Serviceable hearing was preserved in 60.0% of SRS patients, 63.2% of HypoFSRT patients, and 44.4% of ConFSRT patients (p = 0.6). Similarly, there were no significant differences in 5-year rates of trigeminal toxicity facial nerve toxicity, vestibular dysfunction, or tinnitus. Equivalent 5-year PFR and toxicity rates are shown for patients with vestibular schwanoma selected for SRS, HypoFSRT, and ConFSRT after multidisciplinary evaluation. Factors correlating with tumor progression included NF2 and larger tumor size.

Image fusion pitfalls for cranial radiosurgery.

PubMed

Jonker, Benjamin P

2013-01-01

Stereotactic radiosurgery requires imaging to define both the stereotactic space in which the treatment is delivered and the target itself. Image fusion is the process of using rotation and translation to bring a second image set into alignment with the first image set. This allows the potential concurrent use of multiple image sets to define the target and stereotactic space. While a single magnetic resonance imaging (MRI) sequence alone can be used for delineation of the target and fiducials, there may be significant advantages to using additional imaging sets including other MRI sequences, computed tomography (CT) scans, and advanced imaging sets such as catheter-based angiography, diffusor tension imaging-based fiber tracking and positon emission tomography in order to more accurately define the target and surrounding critical structures. Stereotactic space is usually defined by detection of fiducials on the stereotactic head frame or mask system. Unfortunately MRI sequences are susceptible to geometric distortion, whereas CT scans do not face this problem (although they have poorer resolution of the target in most cases). Thus image fusion can allow the definition of stereotactic space to proceed from the geometrically accurate CT images at the same time as using MRI to define the target. The use of image fusion is associated with risk of error introduced by inaccuracies of the fusion process, as well as workflow changes that if not properly accounted for can mislead the treating clinician. The purpose of this review is to describe the uses of image fusion in stereotactic radiosurgery as well as its potential pitfalls.

Image fusion pitfalls for cranial radiosurgery

PubMed Central

Jonker, Benjamin P.

2013-01-01

Stereotactic radiosurgery requires imaging to define both the stereotactic space in which the treatment is delivered and the target itself. Image fusion is the process of using rotation and translation to bring a second image set into alignment with the first image set. This allows the potential concurrent use of multiple image sets to define the target and stereotactic space. While a single magnetic resonance imaging (MRI) sequence alone can be used for delineation of the target and fiducials, there may be significant advantages to using additional imaging sets including other MRI sequences, computed tomography (CT) scans, and advanced imaging sets such as catheter-based angiography, diffusor tension imaging-based fiber tracking and positon emission tomography in order to more accurately define the target and surrounding critical structures. Stereotactic space is usually defined by detection of fiducials on the stereotactic head frame or mask system. Unfortunately MRI sequences are susceptible to geometric distortion, whereas CT scans do not face this problem (although they have poorer resolution of the target in most cases). Thus image fusion can allow the definition of stereotactic space to proceed from the geometrically accurate CT images at the same time as using MRI to define the target. The use of image fusion is associated with risk of error introduced by inaccuracies of the fusion process, as well as workflow changes that if not properly accounted for can mislead the treating clinician. The purpose of this review is to describe the uses of image fusion in stereotactic radiosurgery as well as its potential pitfalls. PMID:23682338

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

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.

Cost-effectiveness Analysis of Stereotactic Radiosurgery Alone Versus Stereotactic Radiosurgery with Upfront Whole Brain Radiation Therapy for Brain Metastases.

PubMed

Kim, H; Rajagopalan, M S; Beriwal, S; Smith, K J

2017-10-01

Stereotactic radiosurgery (SRS) alone or upfront whole brain radiation therapy (WBRT) plus SRS are the most commonly used treatment options for one to three brain oligometastases. The most recent randomised clinical trial result comparing SRS alone with upfront WBRT plus SRS (NCCTG N0574) has favoured SRS alone for neurocognitive function, whereas treatment options remain controversial in terms of cognitive decline and local control. The aim of this study was to conduct a cost-effectiveness analysis of these two competing treatments. A Markov model was constructed for patients treated with SRS alone or SRS plus upfront WBRT based on largely randomised clinical trials. Costs were based on 2016 Medicare reimbursement. Strategies were compared using the incremental cost-effectiveness ratio (ICER) and effectiveness was measured in quality-adjusted life years (QALYs). One-way and probabilistic sensitivity analyses were carried out. Strategies were evaluated from the healthcare payer's perspective with a willingness-to-pay threshold of $100 000 per QALY gained. In the base case analysis, the median survival was 9 months for both arms. SRS alone resulted in an ICER of $9917 per QALY gained. In one-way sensitivity analyses, results were most sensitive to variation in cognitive decline rates for both groups and median survival rates, but the SRS alone remained cost-effective for most parameter ranges. Based on the current available evidence, SRS alone was found to be cost-effective for patients with one to three brain metastases compared with upfront WBRT plus SRS. Copyright © 2017 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

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

Clinical results of stereotactic heavy-charged-particle radiosurgery for intracranial angiographically occult vascular malformations

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

Levy, R.P.; Fabrikant, J.I.; Phillips, M.H.

1989-12-01

Angiographically occult vascular malformations (AOVMs) of the brain have been recognized for many years to cause neurologic morbidity and mortality. They generally become symptomatic due to intracranial hemorrhage, focal mass effect, seizures or headaches. The true incidence of AOVMs is unknown, but autopsy studies suggest that they are more common than high-flow angiographically demonstrable arteriovenous malformations (AVMs). We have developed stereotactic heavy-charged-particle Bragg peak radiosurgery for the treatment of inoperable intracranial vascular malformations, using the helium ion beams at the Lawrence Berkeley Laboratory 184-inch Synchrocyclotron and Bevatron. This report describes the protocol for patient selection, radiosurgical treatment planning method, clinicalmore » and neuroradiologic results and complications encountered, and discusses the strengths and limitations of the method. 10 refs., 1 fig.« less

Characterisation of a plastic scintillation detector to be used in a multicentre stereotactic radiosurgery dosimetry audit

NASA Astrophysics Data System (ADS)

Dimitriadis, A.; Patallo, I. Silvestre; Billas, I.; Duane, S.; Nisbet, A.; Clark, C. H.

2017-11-01

Scintillation detectors are considered highly suitable for dosimetric measurement of small fields in radiotherapy due to their near-tissue equivalence and their small size. A commercially available scintillation detector, the Exradin W1 (Standard Imaging, Middleton, USA), has been previously characterised by two independent studies (Beierholm et al., 2014; Carrasco et al., 2015a, 2015b) but the results from these publications differed in some aspects (e.g. energy dependence, long term stability). The respective authors highlighted the need for more studies to be published (Beierholm et al., 2015; Carrasco et al., 2015a, 2015b). In this work, the Exradin W1 was characterised in terms of dose response, dependence on dose rate, energy, temperature and angle of irradiation, and long-term stability. The observed dose linearity, short-term repeatability and temperature dependence were in good agreement with previously published data. Appropriate corrections should therefore be applied, where possible, in order to achieve measurements with low-uncertainty. The angular dependence was characterised along both the symmetrical and polar axis of the detector for the first time in this work and a dose variation of up to 1% was observed. The response of the detector was observed to decrease at a rate of approximately 1.6% kGy-1 for the first 5 kGy delivered, and then stabilised to 0.2% kGy-1 in the subsequent 20 kGy. The main goal of this work was to assess the suitability of the Exradin W1 for use in dose verification measurements for stereotactic radiosurgery. The results obtained confirm that the detector is suitable for use in such situations. The detector is now utilised in a multi-centre stereotactic radiosurgery dosimetric audit, with the application of appropriate correction factors.

Predicting the Risk of Developing New Cerebral Lesions After Stereotactic Radiosurgery or Fractionated Stereotactic Radiotherapy for Brain Metastases from Renal Cell Carcinoma.

PubMed

Rades, Dirk; Dziggel, Liesa; Blanck, Oliver; Gebauer, Niklas; Bartscht, Tobias; Schild, Steven E

2018-05-01

To create an instrument for estimating the risk of new brain metastases after stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) alone in patients with renal cell carcinoma (RCC). In 45 patients with 1-3 brain metastases, seven characteristics were analyzed for association with freedom from new brain metastases (age, gender, performance score, number and sites of brain metastases, extra-cerebral metastasis, interval from RCC diagnosis to SRS/FSRT). Lower risk of subsequent brain lesions after RT was associated with single metastasis (p=0.043) and supratentorial involvement only (p=0.018). Scoring points were: One metastasis=1, 2-3 metastases=0, supratentorial alone=1, infratentorial with/without supratentorial=0. Scores of 0, 1 and 2 points were associated with 6-month rates of freedom from subsequent brain lesions of 25%, 74% and 92% (p=0.008). After combining groups with 1 and 2 points, 6-month rates were 25% for those with 0 points and 83% for those with 1-2 points (p=0.002). Two groups were identified with different risks of new brain metastases after SRS or FSRT alone. High-risk patients may benefit from additional whole-brain irradiation. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

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

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

SU-F-T-593: Technical Treatment Accuracy in a Clinic of Fractionated Stereotactic Radiosurgery

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

Bisht, R; Kale, S; Natanasabapathi, G

2016-06-15

Purpose: The purpose of this study is to estimate technical treatment accuracy in fractionated stereotactic radiosurgery (fSRS) using extend system (ES) of Gamma Knife (GK). Methods: The fSRS with GK relies on a patient specific re-locatable immobilization system. The reference treatment position is estimated using a digital probe and a repositioning check tool (RCT). The “calibration values” of RCT apertures were compared with measured values on RCT-QA tool to evaluate the standard error (SE) associated with RCT measurements. A treatment plan with single “4 mm collimator shot” was created to deliver a radiation dose of 5 Gy at the predefinedmore » plane of a newly designed in-house head-neck phantom. The plan was investigated using radiochromic EBT3 films. The stereotactic CT imaging of a designed mini CT phantom and distortion study of MR imaging, were combined to calculate imaging SE. The focal precision check for GK machine tolerance was performed using a central diode test tool. Results: Twenty observations of RCT and digital probe, shown the SE of +/−0.0186mm and +/−0.0002mm respectively. A mean positional shift of 0.2752mm (σ=0.0696mm) was observed for twenty similar treatment settings of head-neck phantom. The difference between radiological and predefined exposure point was 0.4650mm and 0.4270mm; for two independent experiments. The imaging studies showed a combined SE of +/− 0.1055mm. Twenty frequent runs of a diode test tool showed the tolerance SE of +/−0.0096mm. If, the measurements are considered to be at 95% of confidence level, an expanded uncertainty was evaluated as +/− 0.2371mm with our system. The positional shift, when combined with an expanded uncertainty, a trivial variation of 0.07mm (max) was observed in comparing resultant radiological precision through film investigations. Conclusion: The study proposes an expression of “technical treatment accuracy” within “known uncertainties” is rational in the estimation

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.

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.

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

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

PubMed

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

2013-12-01

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

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

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.

Assessment of Geometrical Accuracy of Multimodal Images Used for Treatment Planning in Stereotactic Radiotherapy and Radiosurgery: CT, MRI and PET

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

Garcia-Garduno, O. A.; Larraga-Gutierrez, J. M.; Celis, M. A.

2006-09-08

An acrylic phantom was designed and constructed to assess the geometrical accuracy of CT, MRI and PET images for stereotactic radiotherapy (SRT) and radiosurgery (SRS) applications. The phantom was suited for each image modality with a specific tracer and compared with CT images to measure the radial deviation between the reference marks in the phantom. It was found that for MRI the maximum mean deviation is 1.9 {+-} 0.2 mm compared to 2.4 {+-} 0.3 mm reported for PET. These results will be used for margin outlining in SRS and SRT treatment planning.

Feasibility evaluation of a motion detection system with face images for stereotactic radiosurgery.

PubMed

Yamakawa, Takuya; Ogawa, Koichi; Iyatomi, Hitoshi; Kunieda, Etsuo

2011-01-01

In stereotactic radiosurgery we can irradiate a targeted volume precisely with a narrow high-energy x-ray beam, and thus the motion of a targeted area may cause side effects to normal organs. This paper describes our motion detection system with three USB cameras. To reduce the effect of change in illuminance in a tracking area we used an infrared light and USB cameras that were sensitive to the infrared light. The motion detection of a patient was performed by tracking his/her ears and nose with three USB cameras, where pattern matching between a predefined template image for each view and acquired images was done by an exhaustive search method with a general-purpose computing on a graphics processing unit (GPGPU). The results of the experiments showed that the measurement accuracy of our system was less than 0.7 mm, amounting to less than half of that of our previous system.

Whole-brain radiotherapy and stereotactic radiosurgery in brain metastases: what is the evidence?

PubMed

Mehta, Minesh P; Ahluwalia, Manmeet S

2015-01-01

The overall local treatment paradigm of brain metastases, which includes whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS), continues to evolve. Local therapies play an important role in the management of brain metastases. The choice of local therapy depends on factors that involve the patient (performance status, expected survival, and age), the prior treatment history, and the tumor (type and subtype, number, size, location of metastases, and extracranial disease status). Multidisciplinary collaboration is required to facilitate an individualized plan to improve the outcome of disease in patients with this life-limiting complication. There has been concern about the neurocognitive effects of WBRT. A number of approaches that mitigate cognitive dysfunction, such as pharmacologic intervention (memantine) or a hippocampal-sparing strategy, have been studied in a prospective manner with WBRT. Although there has been an increase in the use of SRS in the management of brain metastases in recent years, WBRT retains an important therapeutic role.

Radiosurgery for metastatic disease at the craniocervical junction.

PubMed

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

2014-12-01

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

[Stereotactic radiotherapy and radiosurgery in treatment of patients with intracranial schwannomas].

PubMed

Zolotova, S V; Golanov, A V; Kotel'nikova, T M; Soboleva, O I; Gorlachev, G E; Fil'chenkova, N A; Nikonova, N G; Kapitanov, D N; Makhmudov, U B; Shimanskiĭ, V N; Arutiunov, N V; Pronin, I N

2010-01-01

Aim of this study is to assess the role of stereotactic radiosurgery (SRS) and radiotherapy (SRT) in management of cranial nerves schwannomas by analysis of tumor control, clinical response and variables affecting treatment outcomes. Between April 2005 and January 2009 patients with schwannomas of VIII (63), V (14) and caudal nerves (2) were treated in Burdenko Moscow Neurosurgical Institute using linear accelerator. Mean age was 49 years (13-82). In 42 cases radiation treatment was preceded by surgical resection. 13 patients had type I or II neurofibromatosis. Mean volume of the tumor was 3.9 cm3 (0.5-14.4 cm3) and 13.4 cm3 (2.8-41.3 cm3) for SRS and SRT, respectively. Mean SRS dose was 12 Gy (10.8-14.4 Gy) for vestibular schwannomas and 15 Gy (13.2-18 Gy) for schwannomas of other nerves. In hypofractionated SRT the dose of 35 Gy was delivered in 7 fractions or 30 Gy in 6 fractions. In cases of classical fractioning total dose of 50-60 Gy was divided into daily fractions of 1.8-2.0 Gy. Radiographic tumor control rate reached 97.5% at the last follow-up. 5 patients experienced trigeminal dysfunction, it was transient in 3 cases and persistent in 2. Permanent decline in House-Brackmann facial nerve scale developed in 2 of 79 patients. After treatment effective hearing (class I-II) was preserved in 7 of 9 patients (67%) who had same level of hearing before SRS. Linear accelerator-based stereotactic radiation treatment provides long-term tumor control associated with high rates of preservation of neurological functions. No further tumor surgery was necessary in 100% of cases with solitary tumors with a minimal follow-up of 5 years.

Leukoencephalopathy After Stereotactic Radiosurgery for Brain Metastases

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

Trifiletti, Daniel M., E-mail: daniel.trifiletti@gmail.com; Lee, Cheng-Chia; Schlesinger, David

Purpose: Although the use of stereotactic radiosurgery (SRS) in the treatment of multiple brain metastases has increased dramatically during the past decade to avoid the neurocognitive dysfunction induced by whole brain radiation therapy (WBRT), the cumulative neurocognitive effect of numerous SRS sessions remains unknown. Because leukoencephalopathy is a sensitive marker for radiation-induced central nervous system damage, we studied the clinical and dosimetric predictors of SRS-induced leukoencephalopathy. Methods and Materials: Patients treated at our institution with at least 2 sessions of SRS for brain metastases from 2007 to 2013 were reviewed. The pre- and post-SRS magnetic resonance imaging sequences were reviewedmore » and graded for white matter changes associated with radiation leukoencephalopathy using a previously validated scale. Patient characteristics and SRS dosimetric parameters were reviewed for factors that contributed to leukoencephalopathy using Cox proportional hazards modeling. Results: A total of 103 patients meeting the inclusion criteria were identified. The overall incidence of leukoencephalopathy was 29% at year 1, 38% at year 2, and 53% at year 3. Three factors were associated with radiation-induced leukoencephalopathy: (1) the use of WBRT (P=.019); (2) a higher SRS integral dose to the cranium (P=.036); and (3) the total number of intracranial metastases (P=.003). Conclusions: Our results have established that WBRT plus SRS produces leukoencephalopathy at a much higher rate than SRS alone. In addition, for patients who did not undergo WBRT before SRS, the integral dose was associated with the development of leukoencephalopathy. As the survival of patients with central nervous system metastases increases and as the neurotoxicity of chemotherapeutic and targeted agents becomes established, these 3 potential risk factors will be important to consider.« less

Multileaf collimator-based linear accelerator radiosurgery: five-year efficiency analysis.

PubMed

Lawson, Joshua D; Fox, Tim; Waller, Anthony F; Davis, Lawrence; Crocker, Ian

2009-03-01

In 1989, Emory University initiated a linear accelerator (linac) radiosurgery program using circular collimators. In 2001, the program converted to a multileaf collimator. Since then, the treatment parameters of each patient have been stored in the record-and-verify system. Three major changes have occurred in the radiosurgery program in the past 6 years: in 2002, treatment was changed from static conformal beams to dynamic conformal arc (DCA) therapy, and all patients were imaged before treatment. Beginning in 2005, a linac was used, with the opportunity to treat at higher dose rates (600-1,000 monitor units/min). The aim of this study was to analyze the time required to deliver radiosurgery and the factors affecting treatment delivery. Benchmark data are provided for centers contemplating initiating linac radiosurgery programs. Custom software was developed to mine the record-and-verify system database and automatically perform a chart review on patients who underwent stereotactic radiosurgery from March 2001 to October 2006. The software extracted 510 patients who underwent stereotactic radiosurgery, and the following information was recorded for each patient: treatment technique, treatment time (from initiation of imaging, if done, to completion of therapy), number of isocenters, number of fields, total monitor units, and dose rate. Of the 510 patients, 395 were treated with DCA therapy and 115 with static conformal beams. The average number of isocenters treated was 1.06 (range, 1-4). The average times to deliver treatment were 24.1 minutes for patients who underwent DCA therapy and 19.3 minutes for those treated with static conformal beams, reflecting the lack of imaging in the latter patients. Eighty percent of patients were treated in <30 minutes. For the patients who underwent DCA therapy, the times required to treat 1, 2, 3, and 4 isocenters were 23.9, 24.8, 33.1, and 37.8 minutes, respectively. Average beam-on time for these patients was 11.4 minutes

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

Stereotactic Radiosurgery for Acoustic Neuromas: What Happens Long Term?

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

Roos, Daniel E., E-mail: daniel.roos@health.sa.gov.au; University of Adelaide School of Medicine, Adelaide, South Australia; Potter, Andrew E.

2012-03-15

Purpose: To determine the clinical outcomes for acoustic neuroma treated with low-dose linear accelerator stereotactic radiosurgery (SRS) >10 years earlier at the Royal Adelaide Hospital using data collected prospectively at a dedicated SRS clinic. Methods and Materials: Between November 1993 and December 2000, 51 patients underwent SRS for acoustic neuroma. For the 44 patients with primary SRS for sporadic (unilateral) lesions, the median age was 63 years, the median of the maximal tumor diameter was 21 mm (range, 11-34), and the marginal dose was 14 Gy for the first 4 patients and 12 Gy for the other 40. Results: Themore » crude tumor control rate was 97.7% (1 patient required salvage surgery for progression at 9.75 years). Only 8 (29%) of 28 patients ultimately retained useful hearing (interaural pure tone average {<=}50 dB). Also, although the Kaplan-Meier estimated rate of hearing preservation at 5 years was 57% (95% confidence interval, 38-74%), this decreased to 24% (95% confidence interval, 11-44%) at 10 years. New or worsened V and VII cranial neuropathy occurred in 11% and 2% of patients, respectively; all cases were transient. No case of radiation oncogenesis developed. Conclusions: The long-term follow-up data of low-dose (12-14 Gy) linear accelerator SRS for acoustic neuroma have confirmed excellent tumor control and acceptable cranial neuropathy rates but a continual decrease in hearing preservation out to {>=}10 years.« less

Early experiences of planning stereotactic radiosurgery using 3D printed models of eyes with uveal melanomas

PubMed Central

Furdová, Alena; Sramka, Miron; Thurzo, Andrej; Furdová, Adriana

2017-01-01

Objective The objective of this study was to determine the use of 3D printed model of an eye with intraocular tumor for linear accelerator-based stereotactic radiosurgery. Methods The software for segmentation (3D Slicer) created virtual 3D model of eye globe with tumorous mass based on tissue density from computed tomography and magnetic resonance imaging data. A virtual model was then processed in the slicing software (Simplify3D®) and printed on 3D printer using fused deposition modeling technology. The material that was used for printing was polylactic acid. Results In 2015, stereotactic planning scheme was optimized with the help of 3D printed model of the patient’s eye with intraocular tumor. In the period 2001–2015, a group of 150 patients with uveal melanoma (139 choroidal melanoma and 11 ciliary body melanoma) were treated. The median tumor volume was 0.5 cm3 (0.2–1.6 cm3). The radiation dose was 35.0 Gy by 99% of dose volume histogram. Conclusion The 3D printed model of eye with tumor was helpful in planning the process to achieve the optimal scheme for irradiation which requires high accuracy of defining the targeted tumor mass and critical structures. PMID:28203052

Stereotactic radiosurgery for arteriovenous malformations after Onyx embolization: a case-control study.

PubMed

Lee, Cheng-Chia; Chen, Ching-Jen; Ball, Benjamin; Schlesinger, David; Xu, Zhiyuan; Yen, Chun-Po; Sheehan, Jason

2015-07-01

Onyx, an ethylene-vinyl alcohol copolymer mixed in a dimethyl sulfoxide solvent, is currently one of the most widely used liquid materials for embolization of intracranial arteriovenous malformations (AVMs). The goal of this study was to define the risks and benefits of stereotactic radiosurgery (SRS) for patients who have previously undergone partial AVM embolization with Onyx. Among a consecutive series of 199 patients who underwent SRS between January 2007 and December 2012 at the University of Virginia, 25 patients had Onyx embolization prior to SRS (the embolization group). To analyze the obliteration rates and complications, 50 patients who underwent SRS without prior embolization (the no-embolization group) were matched by propensity score method. The matched variables included age, sex, nidus volume before SRS, margin dose, Spetzler-Martin grade, Virginia Radiosurgery AVM Scale score, and median imaging follow-up period. After Onyx embolization, 18 AVMs were reduced in size. Total obliteration was achieved in 6 cases (24%) at a median of 27.5 months after SRS. In the no-embolization group, total obliteration was achieved in 20 patients (40%) at a median of 22.4 months after SRS. Kaplan-Meier analysis demonstrated obliteration rates of 17.7% and 34.1% in the embolization group at 2 and 4 years, respectively. In the no-embolization group, the corresponding obliteration rates were 27.0% and 55.9%. The between-groups difference in obliteration rates after SRS did not achieve statistical significance. The difference in complications, including adverse radiation effects, hemorrhage episodes, seizure control, and patient mortality also did not reach statistical significance. Onyx embolization can effectively reduce the size of many AVMs. This case-control study did not show any statistically significant difference in the rates of embolization or complications after SRS in patients who had previously undergone Onyx embolization and those who had not.

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.

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

SU-E-T-84: Comparison of Three Different Systems for Patient-Specific Quality Assurance: Cranial Stereotactic Radiosurgery Using VMAT with Multiple Non Coplanar Arcs

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

Fusella, M; Fiandra, C; Giglioli, F

2014-06-01

Purpose: Patient-specific quality assurance in volumetric modulated arc therapy (VMAT) brain stereotactic radiosurgery raises specific issues on dosimetric procedures, mainly represented by the small radiation fields associated with the lack of lateral electronic equilibrium, the need of small detectors and the high dose delivered. The purpose of the study is to compare three different dosimeters for pre-treatment QA. Methods: Nineteen patients (affected by neurinomas, brain metastases, and by meningiomas) were treated with VMAT plans computed on a Monte Carlo based TPS. Gafchromic films inside a slab phantom (GF), 3-D cylindrical phantom with two orthogonal diodes array (DA), and 3-D cylindricalmore » phantom with a single rotating ionization chambers array (ICA), have been evaluated. The dosimeters are, respectively, characterized by a spatial resolution of: 0.4 (in our method), 5 and 2.5 mm. For GF we used a double channel method for calibration and reading protocol; for DA and ICA we used the 3-D dose distributions reconstructed by the two software sold with the dosimeters. With the need of a common system for analyze different measuring approaches, we used an in-house software that analyze a single coronal plane in the middle of the phantoms and Gamma values (2% / 2 mm and 3% / 3 mm) were computed for all patients and dosimeters. Results: The percentage of points with gamma values less than one was: 95.7% for GF, 96.8% for DA and 95% for ICA, using 3%/3mm criteria, and 90.1% for GF, 92.4% for DA and 92% for ICA, using 2% / 2mm gamma criteria. Tstudent test p-values obtained by comparing the three datasets were not statistically significant for both gamma criteria. Conclusion: Gamma index analysis is not affected by different spatial resolution of the three dosimeters.« less

Evaluations of the setup discrepancy between BrainLAB 6D ExacTrac and cone-beam computed tomography used with the imaging guidance system Novalis-Tx for intracranial stereotactic radiosurgery.

PubMed

Oh, Se An; Park, Jae Won; Yea, Ji Woon; Kim, Sung Kyu

2017-01-01

The objective of this study was to evaluate the setup discrepancy between BrainLAB 6 degree-of-freedom (6D) ExacTrac and cone-beam computed tomography (CBCT) used with the imaging guidance system Novalis Tx for intracranial stereotactic radiosurgery. We included 107 consecutive patients for whom white stereotactic head frame masks (R408; Clarity Medical Products, Newark, OH) were used to fix the head during intracranial stereotactic radiosurgery, between August 2012 and July 2016. The patients were immobilized in the same state for both the verification image using 6D ExacTrac and online 3D CBCT. In addition, after radiation treatment, registration between the computed tomography simulation images and the CBCT images was performed with offline 6D fusion in an offline review. The root-mean-square of the difference in the translational dimensions between the ExacTrac system and CBCT was <1.01 mm for online matching and <1.10 mm for offline matching. Furthermore, the root-mean-square of the difference in the rotational dimensions between the ExacTrac system and the CBCT were <0.82° for online matching and <0.95° for offline matching. It was concluded that while the discrepancies in residual setup errors between the ExacTrac 6D X-ray and the CBCT were minor, they should not be ignored.

The efficacy of fractionated radiotherapy and stereotactic radiosurgery for pituitary adenomas: long-term results of 125 consecutive patients treated in a single institution.

PubMed

Kong, Doo-Sik; Lee, Jung-Il; Lim, Do Hoon; Kim, Kwang Won; Shin, Hyung Jin; Nam, Do-Hyun; Park, Kwan; Kim, Jong Hyun

2007-08-15

The objective of this retrospective cohort study was to define the efficacy and safety of fractionated radiotherapy (FRT) and stereotactic radiosurgery (SRS) for the treatment of patients with pituitary adenoma. Between January 1995 and April 2006, 125 consecutive patients with pituitary adenomas (54 hormone-secreting adenomas and 71 nonsecretory adenomas) received FRT or underwent SRS. Sixty-four patients received FRT, for which the mean total dose was 50.4 grays (Gy) (range, 48-54 Gy), and 61 patients underwent gamma-knife SRS with mean marginal dose of 25.1 Gy (range, 9-30 Gy). After mean follow up of 36.7 months, the tumor volume was increased in only 4 patients (3.2%). The overall actuarial progression-free survival rate was 99% at 2 years and 97% at 4 years. No difference was observed between the FRT group and the SRS group in the control of tumor growth. Based on the endocrinologic results in the patients who had secretory adenomas, the overall hormone complete remission rate was 26.2% at 2 years and 76.3% at 4 years. The median time to complete remission was 26 months in the SRS group and 63 months in the FRT group (P = .0068). Hypopituitarism developed as a delayed complication in 11.5% of patients at a median of 84 months. Both FRT and SRS were efficient treatment modalities for the control of tumor growth in patients with pituitary adenomas. The current results indicated that single-dose radiosurgery more promptly produces an effect on the hypersecretion of pituitary hormones and may be recommended over FRT for suitable patients.

Dosimetric measurements of Onyx embolization material for stereotactic radiosurgery

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

Roberts, Donald A.; Balter, James M.; Chaudhary, Neeraj

2012-11-15

Purpose: Arteriovenous malformations are often treated with a combination of embolization and stereotactic radiosurgery. Concern has been expressed in the past regarding the dosimetric properties of materials used in embolization and the effects that the introduction of these materials into the brain may have on the quality of the radiosurgery plan. To quantify these effects, the authors have taken large volumes of Onyx 34 and Onyx 18 (ethylene-vinyl alcohol copolymer doped with tantalum) and measured the attenuation and interface effects of these embolization materials. Methods: The manufacturer provided large cured volumes ({approx}28 cc) of both Onyx materials. These samples weremore » 8.5 cm in diameter with a nominal thickness of 5 mm. The samples were placed on a block tray above a stack of solid water with an Attix chamber at a depth of 5 cm within the stack. The Attix chamber was used to measure the attenuation. These measurements were made for both 6 and 16 MV beams. Placing the sample directly on the solid water stack and varying the thickness of solid water between the sample and the Attix chamber measured the interface effects. The computed tomography (CT) numbers for bulk material were measured in a phantom using a wide bore CT scanner. Results: The transmission through the Onyx materials relative to solid water was approximately 98% and 97% for 16 and 6 MV beams, respectively. The interface effect shows an enhancement of approximately 2% and 1% downstream for 16 and 6 MV beams. CT numbers of approximately 2600-3000 were measured for both materials, which corresponded to an apparent relative electron density (RED) {rho}{sub e}{sup w} to water of approximately 2.7-2.9 if calculated from the commissioning data of the CT scanner. Conclusions: We performed direct measurements of attenuation and interface effects of Onyx 34 and Onyx 18 embolization materials with large samples. The introduction of embolization materials affects the dose distribution of a

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

Awake craniotomy for excision of arteriovenous malformations? A qualitative comparison study with stereotactic radiosurgery.

PubMed

Chan, David Yuen Chung; Chan, Danny Tat Ming; Zhu, Cannon Xian Lun; Kan, Patricia Kwok Yee; Ng, Amelia Yikjin; Hsieh, Yi-Pin Sonia; Abrigo, Jill; Poon, Wai Sang; Wong, George Kwok Chu

2018-05-01

Treatment of arteriovenous malformations (AVM) located at the eloquent area has been a challenge. Awake brain mapping allows identification of a non-eloquent gyrus for intervention and can potentially facilitate resection with preservation of functions. An alternative treatment option is stereotactic radiosurgery (SRS). The objective of this study was to perform a qualitative comparison of the treatment outcome of awake AVM excision versus SRS. We conducted a 13-year retrospective review of AVM excision under awake craniotomy performed at Prince of Wales Hospital, Hong Kong, from 2003 to 2016. Patients' presentation, Spetzler-Martin (SM) grading, rate of obliteration and complication were reviewed and analyzed with the modified radiosurgery-based AVM score (RS score). Six patients had excision of AVM under awake mapping during this period of time. Two were SM Grade II and four were SM Grade III. Five located at the peri-rolandic region while one at the temporal language area. None had failed mapping. Five out of six achieved complete obliteration (83.3%). Qualitative comparative analysis had revealed better treatment outcome with awake AVM excision as compared to SRS with the obliteration rate of 100% versus 96% for RS score ≤1.00, 100% versus 78% for RS score 1.01-1.50, and 66% versus 50% for RS score >2.00 respectively. In conclusion, awake mapping and excision of AVMs at the eloquent area is feasible. Qualitative comparative analysis had revealed higher obliteration rate with awake AVM excision as compared to SRS. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

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.

Total target volume is a better predictor of whole brain dose from gamma stereotactic radiosurgery than the number, shape, or location of the lesions

PubMed Central

Narayanasamy, Ganesh; Smith, Adam; Van Meter, Emily; McGarry, Ronald; Molloy, Janelle A.

2013-01-01

Purpose: To assess the hypothesis that the volume of whole brain that receives a certain dose level is primarily dependent on the treated volume rather than on the number, shape, or location of the lesions. This would help a physician validate the suitability of GammaKnife® based stereotactic radiosurgery (GKSR) prior to treatment. Methods: Simulation studies were performed to establish the hypothesis for both oblong and spherical shaped lesions of various numbers and sizes. Forty patients who underwent GKSR [mean age of 54 years (range 7–80), mean number of lesions of 2.5 (range 1–6), and mean lesion volume of 4.4 cm3 (range 0.02–22.2 cm3)] were also studied retrospectively. Following recommendations of QUANTEC, the volume of brain irradiated by the 12 Gy (VB12) isodose line was measured and a power-law based relation is proposed here for estimating VB12 from the known tumor volume and the prescription dose. Results: In the simulation study on oblong, spherical, and multiple lesions, the volume of brain irradiated by 50%, 10%, and 1% of maximum dose was found to have linear, linear, and exponentially increasing dependence on the volume of the treated region, respectively. In the retrospective study on 40 GKSR patients, a similar relationship was found to predict the brain dose with a Spearman correlation coefficient >0.9. In both the studies, the volume of brain irradiated by a certain dose level does not have a statistically significant relationship (p ≥ 0.05) with the number, shape, or position of the lesions. The measured VB12 agrees with calculation to within 1.7%. Conclusions: The results from the simulation and the retrospective clinical studies indicate that the volume of whole brain that receives a certain percentage of the maximum dose is primarily dependent on the treated volume and less on the number, shape, and location of the lesions. PMID:24007147

Stereotactic radiosurgery for deep intracranial arteriovenous malformations, part 1: Brainstem arteriovenous malformations.

PubMed

Cohen-Inbar, Or; Ding, Dale; Chen, Ching-Jen; Sheehan, Jason P

2016-02-01

The management of brainstem arteriovenous malformations (AVM) are one of the greatest challenges encountered by neurosurgeons. Brainstem AVM have a higher risk of hemorrhage compared to AVM in other locations, and rupture of these lesions commonly results in devastating neurological morbidity and mortality. The potential morbidity associated with currently available treatment modalities further compounds the complexity of decision making for affected patients. Stereotactic radiosurgery (SRS) has an important role in the management of brainstem AVM. SRS offers acceptable obliteration rates with lower risks of hemorrhage occurring during the latency period. Complex nidal architecture requires a multi-disciplinary treatment approach. Nidi partly involving subpial/epipial regions of the dorsal midbrain or cerebellopontine angle should be considered for a combination of endovascular embolization, micro-surgical resection and SRS. Considering the fact that incompletely obliterated lesions (even when reduced in size) could still cause lethal hemorrhages, additional treatment, including repeat SRS and surgical resection should be considered when complete obliteration is not achieved by first SRS. Patients with brainstem AVM require continued clinical and radiological observation and follow-up after SRS, well after angiographic obliteration has been confirmed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Clinical and Radiographic Outcomes From Repeat Whole-brain Radiation Therapy for Brain Metastases in the Age of Stereotactic Radiosurgery.

PubMed

Guo, Susan; Balagamwala, Ehsan H; Reddy, Chandana; Elson, Paul; Suh, John H; Chao, Samuel T

2016-06-01

Repeating whole-brain radiation therapy (WBRT) in patients with progressive/recurrent brain metastases is controversial. We retrospectively reviewed our experience of repeat WBRT in an era where stereotactic radiosurgery was also available. In our IRB-approved database, 49 patients received repeat WBRT from 1996 to 2011. Median initial dose of WBRT was 30 Gy in 10 fractions (range, 27 to 37.5 Gy); median reirradiation dose was 20 Gy in 10 fractions (range, 14 to 30 Gy). Median Karnofsky performance status (KPS) at reirradiation was 70 (range, 40 to 90). Median number of discrete lesions at reirradiation was 6 (range, 1 to 30). Median interval between initial diagnosis of brain metastases and relapse requiring repeat WBRT was 11.5 months (range, 1.5 to 49.2 mo). Overall survival and relapse-free survival were summarized using the Kaplan-Meier method. The log-rank test was used to compare outcomes between groups. Ninety percent of patients completed repeat WBRT. Median survival after repeat WBRT was 3 months (95% CI, 1.9-4.0). Thirteen patients had improved neurological symptoms (27%), 12 were stable (24%), and 14 had worsening symptoms (29%). On radiographic follow-up of 22 patients, 10 (46%) were improved, 4 (18%) were stable, and 8 (36%) progressed. Improved neurological symptoms after repeat WBRT and higher KPS at first follow-up were associated with improved survival (P=0.05 and 0.02). Repeat WBRT was well tolerated. Modest survival times are seen. Prognostic factors for survival include improved neurological symptoms after repeat WBRT and higher KPS at first follow-up. Repeat WBRT may be useful to improve neurological symptoms in patients with limited treatment options, especially those who are not appropriate stereotactic radiosurgery candidates.

Maximum kinetic energy considerations in proton stereotactic radiosurgery.

PubMed

Sengbusch, Evan R; Mackie, Thomas R

2011-04-12

The purpose of this study was to determine the maximum proton kinetic energy required to treat a given percentage of patients eligible for stereotactic radiosurgery (SRS) with coplanar arc-based proton therapy, contingent upon the number and location of gantry angles used. Treatment plans from 100 consecutive patients treated with SRS at the University of Wisconsin Carbone Cancer Center between June of 2007 and March of 2010 were analyzed. For each target volume within each patient, in-house software was used to place proton pencil beam spots over the distal surface of the target volume from 51 equally-spaced gantry angles of up to 360°. For each beam spot, the radiological path length from the surface of the patient to the distal boundary of the target was then calculated along a ray from the gantry location to the location of the beam spot. This data was used to generate a maximum proton energy requirement for each patient as a function of the arc length that would be spanned by the gantry angles used in a given treatment. If only a single treatment angle is required, 100% of the patients included in the study could be treated by a proton beam with a maximum kinetic energy of 118 MeV. As the length of the treatment arc is increased to 90°, 180°, 270°, and 360°, the maximum energy requirement increases to 127, 145, 156, and 179 MeV, respectively. A very high percentage of SRS patients could be treated at relatively low proton energies if the gantry angles used in the treatment plan do not span a large treatment arc. Maximum proton kinetic energy requirements increase linearly with size of the treatment arc.

Cone-beam CT image contrast and attenuation-map linearity improvement (CALI) for brain stereotactic radiosurgery procedures

NASA Astrophysics Data System (ADS)

Hashemi, Sayed Masoud; Lee, Young; Eriksson, Markus; Nordström, Hâkan; Mainprize, James; Grouza, Vladimir; Huynh, Christopher; Sahgal, Arjun; Song, William Y.; Ruschin, Mark

2017-03-01

A Contrast and Attenuation-map (CT-number) Linearity Improvement (CALI) framework is proposed for cone-beam CT (CBCT) images used for brain stereotactic radiosurgery (SRS). The proposed framework is used together with our high spatial resolution iterative reconstruction algorithm and is tailored for the Leksell Gamma Knife ICON (Elekta, Stockholm, Sweden). The incorporated CBCT system in ICON facilitates frameless SRS planning and treatment delivery. The ICON employs a half-cone geometry to accommodate the existing treatment couch. This geometry increases the amount of artifacts and together with other physical imperfections causes image inhomogeneity and contrast reduction. Our proposed framework includes a preprocessing step, involving a shading and beam-hardening artifact correction, and a post-processing step to correct the dome/capping artifact caused by the spatial variations in x-ray energy generated by bowtie-filter. Our shading correction algorithm relies solely on the acquired projection images (i.e. no prior information required) and utilizes filtered-back-projection (FBP) reconstructed images to generate a segmented bone and soft-tissue map. Ideal projections are estimated from the segmented images and a smoothed version of the difference between the ideal and measured projections is used in correction. The proposed beam-hardening and dome artifact corrections are segmentation free. The CALI was tested on CatPhan, as well as patient images acquired on the ICON system. The resulting clinical brain images show substantial improvements in soft contrast visibility, revealing structures such as ventricles and lesions which were otherwise un-detectable in FBP-reconstructed images. The linearity of the reconstructed attenuation-map was also improved, resulting in more accurate CT#.

Predictive factors of tumor control and survival after radiosurgery for local failures of nasopharyngeal carcinoma.

PubMed

Chua, Daniel T T; Sham, Jonathan S T; Hung, Kwan-Ngai; Leung, Lucullus H T; Au, Gordon K H

2006-12-01

Stereotactic radiosurgery has been employed as a salvage treatment of local failures of nasopharyngeal carcinoma (NPC). To identify patients that would benefit from radiosurgery, we reviewed our data with emphasis on factors that predicted treatment outcome. A total of 48 patients with local failures of NPC were treated by stereotactic radiosurgery between March 1996 and February 2005. Radiosurgery was administered using a modified linear accelerator with single or multiple isocenters to deliver a median dose of 12.5 Gy to the target periphery. Median follow-up was 54 months. Five-year local failure-free probability after radiosurgery was 47.2% and 5-year overall survival rate was 46.9%. Neuroendocrine complications occurred in 27% of patients but there were no treatment-related deaths. Time interval from primary radiotherapy, retreatment T stage, prior local failures and tumor volume were significant predictive factors of local control and/or survival whereas age was of marginal significance in predicting survival. A radiosurgery prognostic scoring system was designed based on these predictive factors. Five-year local failure-free probabilities in patients with good, intermediate and poor prognostic scores were 100%, 42.5%, and 9.6%. The corresponding five-year overall survival rates were 100%, 51.1%, and 0%. Important factors that predicted tumor control and survival after radiosurgery were identified. Patients with good prognostic score should be treated by radiosurgery in view of the excellent results. Patients with intermediate prognostic score may also be treated by radiosurgery but those with poor prognostic score should receive other salvage treatments.

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

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

NASA Astrophysics Data System (ADS)

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

2008-03-01

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

Role of stereotactic radiosurgery in patients with more than four brain metastases

PubMed Central

Jairam, Vikram; Chiang, Veronica LS; Yu, James B; Knisely, Jonathan PS

2013-01-01

SUMMARY For patients presenting with brain metastases, two methods of radiation treatment currently exist: stereotactic radiosurgery (SRS) and whole-brain radiation therapy (WBRT). SRS is a minimally invasive to noninvasive technique that delivers a high dose of ionizing radiation to a precisely defined focal target volume, whereas WBRT involves multiple smaller doses of radiation delivered to the whole brain. Evidence exists from randomized controlled trials for SRS in the treatment of patients with one to four brain metastases. Patients with more than four brain metastases generally receive WBRT, which can effectively treat undetected metastases and protect against intracranial relapse. However, WBRT has been associated with an increased potential for toxic neurocognitive side effects, including memory loss and early dementia, and does not provide 100% protection against relapse. For this reason, physicians at many medical centers are opting to use SRS as first-line treatment for patients with more than four brain metastases, despite evidence showing an increased rate of intracranial relapse compared with WBRT. In light of the evolving use of SRS, this review will examine the available reports on institutional trials and outcomes for patients with more than four brain metastases treated with SRS alone as first-line therapy. PMID:24273642

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

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

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

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

Comparison of stereotactic radiosurgery and fractionated stereotactic radiotherapy of acoustic neurinomas according to 3-D tumor volume shrinkage and quality of life.

PubMed

Henzel, Martin; Hamm, Klaus; Sitter, Helmut; Gross, Markus W; Surber, Gunnar; Kleinert, Gabriele; Engenhart-Cabillic, Rita

2009-09-01

Stereotactic radiosurgery (SRS) and also fractionated stereotactic radiotherapy (SRT) offer high local control (LC) rates (> 90%). This study aimed to evaluate three-dimensional (3-D) tumor volume (TV) shrinkage and to assess quality of life (QoL) after SRS/SRT. From 1999 to 2005, 35/74 patients were treated with SRS, and 39/74 with SRT. Median age was 60 years. Treatment was delivered by a linear accelerator. Median single dose was 13 Gy (SRS) or 54 Gy (SRT). Patients were followed up > or = 12 months after SRS/SRT. LC and toxicity were evaluated by clinical examinations and magnetic resonance imaging. 3-D TV shrinkage was evaluated with the planning system. QoL was assessed using the questionnaire Short Form-36. Median follow-up was 50/36 months (SRS/SRT). Actuarial 5-year freedom from progression/overall survival was 88.1%/100% (SRS), and 87.5%/87.2% (SRT). TV shrinkage was 15.1%/40.7% (SRS/SRT; p = 0.01). Single dose (< 13 Gy) was the only determinant factor for TV shrinkage after SRS (p = 0.001). Age, gender, initial TV, and previous operations did not affect TV shrinkage. Acute or late toxicity (> or = grade 3) was never seen. Concerning QoL, no significant differences were observed after SRS/SRT. Previous operations and gender did not affect QoL (p > 0.05). Compared with the German normal population, patients had worse values for all domains except for mental health. TV shrinkage was significantly higher after SRT than after SRS. Main symptoms were not affected by SRS/SRT. Retrospectively, QoL was neither affected by SRS nor by SRT.

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.

MRI-Related Geometric Distortions in Stereotactic Radiotherapy Treatment Planning: Evaluation and Dosimetric Impact.

PubMed

Pappas, Eleftherios P; Alshanqity, Mukhtar; Moutsatsos, Argyris; Lababidi, Hani; Alsafi, Khalid; Georgiou, Konstantinos; Karaiskos, Pantelis; Georgiou, Evangelos

2017-12-01

In view of their superior soft tissue contrast compared to computed tomography, magnetic resonance images are commonly involved in stereotactic radiosurgery/radiotherapy applications for target delineation purposes. It is known, however, that magnetic resonance images are geometrically distorted, thus deteriorating dose delivery accuracy. The present work focuses on the assessment of geometric distortion inherent in magnetic resonance images used in stereotactic radiosurgery/radiotherapy treatment planning and attempts to quantitively evaluate the consequent impact on dose delivery. The geometric distortions for 3 clinical magnetic resonance protocols (at both 1.5 and 3.0 T) used for stereotactic radiosurgery/radiotherapy treatment planning were evaluated using a recently proposed phantom and methodology. Areas of increased distortion were identified at the edges of the imaged volume which was comparable to a brain scan. Although mean absolute distortion did not exceed 0.5 mm on any spatial axis, maximum detected control point disposition reached 2 mm. In an effort to establish what could be considered as acceptable geometric uncertainty, highly conformal plans were utilized to irradiate targets of different diameters (5-50 mm). The targets were mispositioned by 0.5 up to 3 mm, and dose-volume histograms and plan quality indices clinically used for plan evaluation and acceptance were derived and used to investigate the effect of geometrical uncertainty (distortion) on dose delivery accuracy and plan quality. The latter was found to be strongly dependent on target size. For targets less than 20 mm in diameter, a spatial disposition of the order of 1 mm could significantly affect (>5%) plan acceptance/quality indices. For targets with diameter greater than 2 cm, the corresponding disposition was found greater than 1.5 mm. Overall results of this work suggest that efficacy of stereotactic radiosurgery/radiotherapy applications could be compromised in case of very

The use of spine stereotactic radiosurgery for oligometastatic disease.

PubMed

Ho, Jennifer C; Tang, Chad; Deegan, Brian J; Allen, Pamela K; Jonasch, Eric; Amini, Behrang; Wang, Xin A; Li, Jing; Tatsui, Claudio E; Rhines, Laurence D; Brown, Paul D; Ghia, Amol J

2016-08-01

OBJECTIVE The authors investigated the outcomes following spine stereotactic radiosurgery (SSRS) for patients with oligometastatic disease of the spine. METHODS The study was a secondary analysis of 38 of 209 patients enrolled in 2 separate institutional Phase I/II prospective protocols and treated with SSRS between 2002 and 2011. Of these 38 patients, 33 (87%) were treated for a solitary spine metastasis, with no other history of metastatic disease. SSRS was prescribed to 24 Gy in 1 fraction (8%), 18 Gy in 1 fraction (18%), 16 Gy in 1 fraction (11%), 27 Gy in 3 fractions (53%), 30 Gy in 5 fractions (8%), or 20 Gy in 5 fractions (3%). Seventeen patients (45%) received prior conventional external beam radiation therapy. RESULTS The median overall survival (OS) was 75.7 months, and the 2- and 5-year OS rates were 84% and 60%, respectively. In multivariate analysis, patients who had prior spine surgery and a better Karnofsky Performance Scale score had an improved OS (HR 0.16, 95% CI 0.05-0.52, p < 0.01, and HR 0.33, 95% CI 0.13%-0.84%, p = 0.02, respectively), and those who had undergone prior radiation therapy had a worse OS (HR 3.6, 95% CI 1.2%-10%, p = 0.02). The 1-, 2-, and 5-year local progression-free survival rates were 85%, 82%, and 78%, respectively. The median time to systemic therapy modification was 41 months. Two patients (5%) experienced late Grade 3-4 toxicity. CONCLUSIONS Patients with oligometastatic disease of the spine treated with SSRS can experience long-term survival and a long time before needing a modification in systemic therapy. In addition, SSRS leads to excellent local control and minimal late toxicity.

Biophysical characterization of a relativistic proton beam for image-guided radiosurgery

PubMed Central

Yu, Zhan; Vanstalle, Marie; La Tessa, Chiara; Jiang, Guo-Liang; Durante, Marco

2012-01-01

We measured the physical and radiobiological characteristics of 1 GeV protons for possible applications in stereotactic radiosurgery (image-guided plateau-proton radiosurgery). A proton beam was accelerated at 1 GeV at the Brookhaven National Laboratory (Upton, NY) and a target in polymethyl methacrylate (PMMA) was used. Clonogenic survival was measured after exposures to 1–10 Gy in three mammalian cell lines. Measurements and simulations demonstrate that the lateral scattering of the beam is very small. The lateral dose profile was measured with or without the 20-cm plastic target, showing no significant differences up to 2 cm from the axis A large number of secondary swift protons are produced in the target and this leads to an increase of approximately 40% in the measured dose on the beam axis at 20 cm depth. The relative biological effectiveness at 10% survival level ranged between 1.0 and 1.2 on the beam axis, and was slightly higher off-axis. The very low lateral scattering of relativistic protons and the possibility of using online proton radiography during the treatment make them attractive for image-guided plateau (non-Bragg peak) stereotactic radiosurgery. PMID:22843629

A deep convolutional neural network-based automatic delineation strategy for multiple brain metastases stereotactic radiosurgery

PubMed Central

Stojadinovic, Strahinja; Hrycushko, Brian; Wardak, Zabi; Lau, Steven; Lu, Weiguo; Yan, Yulong; Jiang, Steve B.; Zhen, Xin; Timmerman, Robert; Nedzi, Lucien

2017-01-01

Accurate and automatic brain metastases target delineation is a key step for efficient and effective stereotactic radiosurgery (SRS) treatment planning. In this work, we developed a deep learning convolutional neural network (CNN) algorithm for segmenting brain metastases on contrast-enhanced T1-weighted magnetic resonance imaging (MRI) datasets. We integrated the CNN-based algorithm into an automatic brain metastases segmentation workflow and validated on both Multimodal Brain Tumor Image Segmentation challenge (BRATS) data and clinical patients' data. Validation on BRATS data yielded average DICE coefficients (DCs) of 0.75±0.07 in the tumor core and 0.81±0.04 in the enhancing tumor, which outperformed most techniques in the 2015 BRATS challenge. Segmentation results of patient cases showed an average of DCs 0.67±0.03 and achieved an area under the receiver operating characteristic curve of 0.98±0.01. The developed automatic segmentation strategy surpasses current benchmark levels and offers a promising tool for SRS treatment planning for multiple brain metastases. PMID:28985229

A deep convolutional neural network-based automatic delineation strategy for multiple brain metastases stereotactic radiosurgery.

PubMed

Liu, Yan; Stojadinovic, Strahinja; Hrycushko, Brian; Wardak, Zabi; Lau, Steven; Lu, Weiguo; Yan, Yulong; Jiang, Steve B; Zhen, Xin; Timmerman, Robert; Nedzi, Lucien; Gu, Xuejun

2017-01-01

Accurate and automatic brain metastases target delineation is a key step for efficient and effective stereotactic radiosurgery (SRS) treatment planning. In this work, we developed a deep learning convolutional neural network (CNN) algorithm for segmenting brain metastases on contrast-enhanced T1-weighted magnetic resonance imaging (MRI) datasets. We integrated the CNN-based algorithm into an automatic brain metastases segmentation workflow and validated on both Multimodal Brain Tumor Image Segmentation challenge (BRATS) data and clinical patients' data. Validation on BRATS data yielded average DICE coefficients (DCs) of 0.75±0.07 in the tumor core and 0.81±0.04 in the enhancing tumor, which outperformed most techniques in the 2015 BRATS challenge. Segmentation results of patient cases showed an average of DCs 0.67±0.03 and achieved an area under the receiver operating characteristic curve of 0.98±0.01. The developed automatic segmentation strategy surpasses current benchmark levels and offers a promising tool for SRS treatment planning for multiple brain metastases.

SU-D-BRA-03: Analysis of Systematic Errors with 2D/3D Image Registration for Target Localization and Treatment Delivery in Stereotactic Radiosurgery

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

Xu, H; Chetty, I; Wen, N

Purpose: Determine systematic deviations between 2D/3D and 3D/3D image registrations with six degrees of freedom (6DOF) for various imaging modalities and registration algorithms on the Varian Edge Linac. Methods: The 6DOF systematic errors were assessed by comparing automated 2D/3D (kV/MV vs. CT) with 3D/3D (CBCT vs. CT) image registrations from different imaging pairs, CT slice thicknesses, couch angles, similarity measures, etc., using a Rando head and a pelvic phantom. The 2D/3D image registration accuracy was evaluated at different treatment sites (intra-cranial and extra-cranial) by statistically analyzing 2D/3D pre-treatment verification against 3D/3D localization of 192 Stereotactic Radiosurgery/Stereotactic Body Radiation Therapy treatmentmore » fractions for 88 patients. Results: The systematic errors of 2D/3D image registration using kV-kV, MV-kV and MV-MV image pairs using 0.8 mm slice thickness CT images were within 0.3 mm and 0.3° for translations and rotations with a 95% confidence interval (CI). No significant difference between 2D/3D and 3D/3D image registrations (P>0.05) was observed for target localization at various CT slice thicknesses ranging from 0.8 to 3 mm. Couch angles (30, 45, 60 degree) did not impact the accuracy of 2D/3D image registration. Using pattern intensity with content image filtering was recommended for 2D/3D image registration to achieve the best accuracy. For the patient study, translational error was within 2 mm and rotational error was within 0.6 degrees in terms of 95% CI for 2D/3D image registration. For intra-cranial sites, means and std. deviations of translational errors were −0.2±0.7, 0.04±0.5, 0.1±0.4 mm for LNG, LAT, VRT directions, respectively. For extra-cranial sites, means and std. deviations of translational errors were - 0.04±1, 0.2±1, 0.1±1 mm for LNG, LAT, VRT directions, respectively. 2D/3D image registration uncertainties for intra-cranial and extra-cranial sites were comparable. Conclusion

Stereotactic radiosurgery (SRS) in the modern management of patients with brain metastases

PubMed Central

Soliman, Hany; Das, Sunit; Larson, David A.; Sahgal, Arjun

2016-01-01

Stereotactic radiosurgery (SRS) is an established non-invasive ablative therapy for brain metastases. Early clinical trials with SRS proved that tumor control rates are superior to whole brain radiotherapy (WBRT) alone. As a result, WBRT plus SRS was widely adopted for patients with a limited number of brain metastases (“limited number” customarily means 1-4). Subsequent trials focused on answering whether WBRT upfront was necessary at all. Based on current randomized controlled trials (RCTs) and meta-analyses comparing SRS alone to SRS plus WBRT, adjuvant WBRT results in better intracranial control; however, at the expense of neurocognitive functioning and quality of life. These adverse effects of WBRT may also negatively impact on survival in younger patients. Based on the results of these studies, treatment has shifted to SRS alone in patients with a limited number of metastases. Additionally, RCTs are evaluating the role of SRS alone in patients with >4 brain metastases. New developments in SRS include fractionated SRS for large tumors and the integration of SRS with targeted systemic therapies that cross the blood brain barrier and/or stimulate an immune response. We present in this review the current high level evidence and rationale supporting SRS as the standard of care for patients with limited brain metastases, and emerging applications of SRS. PMID:26848525

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 ...

Intracranial stereotactic radiosurgery with an adapted linear accelerator vs. robotic radiosurgery: Comparison of dosimetric treatment plan quality.

PubMed

Treuer, Harald; Hoevels, Moritz; Luyken, Klaus; Visser-Vandewalle, Veerle; Wirths, Jochen; Kocher, Martin; Ruge, Maximilian

2015-06-01

Stereotactic radiosurgery with an adapted linear accelerator (linac-SRS) is an established therapy option for brain metastases, benign brain tumors, and arteriovenous malformations. We intended to investigate whether the dosimetric quality of treatment plans achieved with a CyberKnife (CK) is at least equivalent to that for linac-SRS with circular or micromultileaf collimators (microMLC). A random sample of 16 patients with 23 target volumes, previously treated with linac-SRS, was replanned with CK. Planning constraints were identical dose prescription and clinical applicability. In all cases uniform optimization scripts and inverse planning objectives were used. Plans were compared with respect to coverage, minimal dose within target volume, conformity index, and volume of brain tissue irradiated with ≥ 10 Gy. Generating the CK plan was unproblematic with simple optimization scripts in all cases. With the CK plans, coverage, minimal target volume dosage, and conformity index were significantly better, while no significant improvement could be shown regarding the 10 Gy volume. Multiobjective comparison for the irradiated target volumes was superior in the CK plan in 20 out of 23 cases and equivalent in 3 out of 23 cases. Multiobjective comparison for the treated patients was superior in the CK plan in all 16 cases. The results clearly demonstrate the superiority of the irradiation plan for CK compared to classical linac-SRS with circular collimators and microMLC. In particular, the average minimal target volume dose per patient, increased by 1.9 Gy, and at the same time a 14% better conformation index seems to be an improvement with clinical relevance.

Tolerance of cranial nerves of the cavernous sinus to radiosurgery

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

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

1993-09-20

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

Canadian Neurosurgery Educators' Views on Stereotactic Radiosurgery in Residency Training.

PubMed

Samuel, Nardin; Philteos, Justine; Alotaibi, Naif M; Ahuja, Christopher; Mansouri, Alireza; Kulkarni, Abhaya V

2018-04-01

Despite the increasing prominence of stereotactic radiosurgery (SRS) in treating intracranial and spinal pathologies, there is currently a dearth of exposure to this modality in the neurosurgical residency. To address this gap, the aim of this study is to assess neurosurgery educators' views regarding the current state of SRS exposure, and to identify potential approaches to improve residency education in this domain. Qualitative thematic analysis and constructivist grounded theory methodology were employed. Semistructured telephone-based interviews were conducted with current or past residency program directors, as well as current departmental chairs across neurosurgical departments in Canada. Interviews were transcribed and subjected to thematic analysis using open and axial coding. Of the 34 eligible participants, the overall response rate was 41.1% (14/34), with a 35.3% participation rate (12/34). Participants represented 9 of the 12 Canadian institutions surveyed. The majority of participants were current program directors (n = 8), followed by past program directors (n = 2), and departmental chairs (n = 2). Most respondents 75% (9/12) view an increasing role for SRS in neurosurgery. Unanimously, respondents endorse greater exposure to SRS during residency through formal residency rotations and engagement in interdisciplinary tumor boards to facilitate involvement in clinical decision-making. This is the first study to systematically collate neurosurgery educators' views on SRS in residency in Canada and demonstrates recognition of the discordance between SRS in practice and residency training. Neurosurgery educators broadly endorse increased exposure to this modality. Future work is needed to delineate the requirements necessary to achieve adequate competency in SRS. Copyright © 2018 Elsevier Inc. All rights reserved.

Single-Isocenter Multiple-Target Stereotactic Radiosurgery: Risk of Compromised Coverage

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

Roper, Justin, E-mail: justin.roper@emory.edu; Department of Biostatistics and Bioinformatics, Winship Cancer Institute of Emory University, Atlanta, Georgia; Chanyavanich, Vorakarn

2015-11-01

Purpose: To determine the dosimetric effects of rotational errors on target coverage using volumetric modulated arc therapy (VMAT) for multitarget stereotactic radiosurgery (SRS). Methods and Materials: This retrospective study included 50 SRS cases, each with 2 intracranial planning target volumes (PTVs). Both PTVs were planned for simultaneous treatment to 21 Gy using a single-isocenter, noncoplanar VMAT SRS technique. Rotational errors of 0.5°, 1.0°, and 2.0° were simulated about all axes. The dose to 95% of the PTV (D95) and the volume covered by 95% of the prescribed dose (V95) were evaluated using multivariate analysis to determine how PTV coverage was relatedmore » to PTV volume, PTV separation, and rotational error. Results: At 0.5° rotational error, D95 values and V95 coverage rates were ≥95% in all cases. For rotational errors of 1.0°, 7% of targets had D95 and V95 values <95%. Coverage worsened substantially when the rotational error increased to 2.0°: D95 and V95 values were >95% for only 63% of the targets. Multivariate analysis showed that PTV volume and distance to isocenter were strong predictors of target coverage. Conclusions: The effects of rotational errors on target coverage were studied across a broad range of SRS cases. In general, the risk of compromised coverage increased with decreasing target volume, increasing rotational error and increasing distance between targets. Multivariate regression models from this study may be used to quantify the dosimetric effects of rotational errors on target coverage given patient-specific input parameters of PTV volume and distance to isocenter.« less

Dosimetry for Small Fields in Stereotactic Radiosurgery Using Gafchromic MD-V2-55 Film, TLD-100 and Alanine Dosimeters

PubMed Central

Massillon-JL, Guerda; Cueva-Prócel, Diego; Díaz-Aguirre, Porfirio; Rodríguez-Ponce, Miguel; Herrera-Martínez, Flor

2013-01-01

This work investigated the suitability of passive dosimeters for reference dosimetry in small fields with acceptable accuracy. Absorbed dose to water rate was determined in nine small radiation fields with diameters between 4 and 35 mm in a Leksell Gamma Knife (LGK) and a modified linear accelerator (linac) for stereotactic radiosurgery treatments. Measurements were made using Gafchromic film (MD-V2-55), alanine and thermoluminescent (TLD-100) dosimeters and compared with conventional dosimetry systems. Detectors were calibrated in terms of absorbed dose to water in 60Co gamma-ray and 6 MV x-ray reference (10×10 cm2) fields using an ionization chamber calibrated at a standards laboratory. Absorbed dose to water rate computed with MD-V2-55 was higher than that obtained with the others dosimeters, possibly due to a smaller volume averaging effect. Ratio between the dose-rates determined with each dosimeter and those obtained with the film was evaluated for both treatment modalities. For the LGK, the ratio decreased as the dosimeter size increased and remained constant for collimator diameters larger than 8 mm. The same behaviour was observed for the linac and the ratio increased with field size, independent of the dosimeter used. These behaviours could be explained as an averaging volume effect due to dose gradient and lack of electronic equilibrium. Evaluation of the output factors for the LGK collimators indicated that, even when agreement was observed between Monte Carlo simulation and measurements with different dosimeters, this does not warrant that the absorbed dose to water rate in the field was properly known and thus, investigation of the reference dosimetry should be an important issue. These results indicated that alanine dosimeter provides a high degree of accuracy but cannot be used in fields smaller than 20 mm diameter. Gafchromic film can be considered as a suitable methodology for reference dosimetry. TLD dosimeters are not appropriate in fields

Verification of the linac isocenter for stereotactic radiosurgery using cine-EPID imaging and arc delivery

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

Rowshanfarzad, Pejman; Sabet, Mahsheed; O' Connor, Daryl J.

2011-07-15

Purpose:Verification of the mechanical isocenter position is required as part of comprehensive quality assurance programs for stereotactic radiosurgery/radiotherapy (SRS/SRT) treatments. Several techniques have been proposed for this purpose but each of them has certain drawbacks. In this paper, a new efficient and more comprehensive method using cine-EPID images has been introduced for automatic verification of the isocenter with sufficient accuracy for stereotactic applications. Methods: Using a circular collimator fixed to the gantry head to define the field, EPID images of a Winston-Lutz phantom were acquired in cine-imaging mode during 360 deg. gantry rotations. A robust matlab code was developed tomore » analyze the data by finding the center of the field and the center of the ball bearing shadow in each image with sub-pixel accuracy. The distance between these two centers was determined for every image. The method was evaluated by comparison to results of a mechanical pointer and also by detection of a manual shift applied to the phantom position. The repeatability and reproducibility of the method were tested and it was also applied to detect couch and collimator wobble during rotation. Results:The accuracy of the algorithm was 0.03 {+-} 0.02 mm. The repeatability was less than 3 {mu}m and the reproducibility was less than 86 {mu}m. The time elapsed for the analysis of more than 100 cine images of Varian aS1000 and aS500 EPIDs were {approx}65 and 20 s, respectively. Processing of images taken in integrated mode took 0.1 s. The output of the analysis software is printable and shows the isocenter shifts as a function of angle in both in-plane and cross-plane directions. It gives warning messages where the shifts exceed the criteria for SRS/SRT and provides useful data for the necessary adjustments in the system including bearing system and/or room lasers. Conclusions: The comprehensive method introduced in this study uses cine-images, is highly accurate

Descriptive Analysis of Oligometastatic Lesions Treated With Curative-Intent Stereotactic Body Radiotherapy

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

Milano, Michael T.; Katz, Alan W.; Schell, Michael C.

Purpose: To characterize oligometastases in patients enrolled on two prospective pilot studies, treating oligometastases with hypofractionated stereotactic body radiotherapy and stereotactic radiosurgery to cranial lesions. Methods and Materials: We describe the characteristics and local control (LC) of 293 lesions in 121 patients with five or fewer metastases treated with stereotactic body radiation and/or cranial stereotactic radiosurgery. For each lesion, the primary cancer site, tumor histology, site of metastasis, gross tumor volume, and prescribed dose were ascertained. The prescribed dose is expressed by the biologically effective dose in 2-Gy fractions (BED2), calculated using the linear quadratic model, assuming an {alpha}/{beta} ratiomore » of 10. Results: Lung lesions were significantly smaller than other lesions in our cohort, whereas liver lesions were significantly larger, possibly reflecting a detection and/or referral bias. The 2-year and 4-year tumor LC rates were 77% and 73% respectively. A larger gross tumor volume was significantly (p < 0.0001) correlated with worse lesion LC. Lesions originating from primary pancreatic, biliary or liver cancer exhibited significantly poorer LC, as did lesions from colorectal cancer. Lesions from breast cancer were better controlled. A higher BED2 did not correlate with improved tumor control. Conclusions: Stereotactic body radiation to aggressively treat oligometastatic lesions results in good local tumor control. Bulkier lesions are more difficult to control and may benefit from dose escalation.« less

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.

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

Radiosurgery for Arteriovenous Malformations and the Impact on Headaches.

PubMed

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

2017-05-01

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

Long-term outcomes after radiosurgery for glomus jugulare tumors.

PubMed

Sallabanda, Kita; Barrientos, Hernan; Isernia Romero, Daniela Angelina; Vargas, Cristian; Gutierrez Diaz, Jose Angel; Peraza, Carmen; Rivin Del Campo, Eleonor; Praena-Fernandez, Juan Manuel; López-Guerra, José Luis

2018-04-01

The treatment of glomus jugulare tumors (GJT) remains controversial due to high morbidity. Historically, these tumors have primarily been managed surgically. The purpose of this retrospective review was to assess the tumor and clinical control rates as well as long-term toxicity of GJT treated with radiosurgery. Between 1993 and 2014, 30 patients with GJT (31 tumors) were managed with radiosurgery. Twenty-one patients were female and the median age was 59 years. Twenty-eight patients (93%) were treated with radiosurgery, typically at 14 Gy ( n = 26), and 2 patients (7%) with stereotactic radiosurgery. Sixteen cases (52%) had undergone prior surgery. The mean follow-up was 4.6 years (range 1.5-12). Crude overall survival, tumor control, clinical control, and long-term grade 1 toxicity rates were 97%, 97%, 97%, and 13% (4/30), respectively. No statistically significant risk factor was associated with lower tumor control in our series. Univariate analysis showed a statistically significant association between patients having 1 cranial nerve (CN) involvement before radiosurgery and a higher risk of lack of improvement of symptoms (odds ratio 5.24, 95% confidence interval 1.06-25.97, p = .043). Radiosurgery is an effective and safe treatment modality for GJT. Patients having 1 CN involvement before radiosurgery show a higher risk of lack of improvement of symptoms.

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

PubMed

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

2012-07-15

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

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

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

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

2012-07-15

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

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

Correlation between heterogeneity index (HI) and gradient index (GI) for high dose stereotactic radiotherapy/radiosurgery (SRT/SRS)

NASA Astrophysics Data System (ADS)

Tas, B.; Durmus, I. F.; Okumus, A.; Uzel, O. E.

2017-02-01

To evaluate between Heterogeneity Index (HI) and Gradient Index (GI) correlation for high dose Stereotactic radiotherapy (SRT) / Stereotactic radiosurgery (SRS) using Versa HD® lineer accelerator. Nine patients with single metastasis were used in this study. Patient's treatment planning were performed using Monaco5.1® Treatment planning system (TPS) with non-coplanar 6MV Flattening filter free (FFF) beams by partial Volumetric modulated arc therapy (VMAT) tecnique for each patient. We determined three different size of metastasis catagory which are less than 1cc, between 1cc and 5cc and larger than 5cc volume. Also, three different HI were calculated for each patients. These are 1.10, 1.20 and 1.30. Mean GI was determined 8.57±2.2 for 1.10 HI, 7.23±1.7 for 1.20 HI and 6.0±1.1 for 1.30 HI for less than 1cc metastasis. Then GI was determined 4.77±0.4 for 1.10 HI, 4.37±0.3 for 1.20 HI and 3.97±0.3 for 1.30 HI for between 1cc and 5cc metastasis. Finally, GI was determined 4.00±0.5 for 1.10 HI,3.63±0.5 for 1.20 HI and 3.27±0.4 for 1.30 HI for larger than 5cc metastasis. These results show that GI depends on significantly size and HI of metastasis especially for less than 1cc.

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.

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

Computer-based radiological longitudinal evaluation of meningiomas following stereotactic radiosurgery.

PubMed

Shimol, Eli Ben; Joskowicz, Leo; Eliahou, Ruth; Shoshan, Yigal

2018-02-01

Stereotactic radiosurgery (SRS) is a common treatment for intracranial meningiomas. SRS is planned on a pre-therapy gadolinium-enhanced T1-weighted MRI scan (Gd-T1w MRI) in which the meningioma contours have been delineated. Post-SRS therapy serial Gd-T1w MRI scans are then acquired for longitudinal treatment evaluation. Accurate tumor volume change quantification is required for treatment efficacy evaluation and for treatment continuation. We present a new algorithm for the automatic segmentation and volumetric assessment of meningioma in post-therapy Gd-T1w MRI scans. The inputs are the pre- and post-therapy Gd-T1w MRI scans and the meningioma delineation in the pre-therapy scan. The output is the meningioma delineations and volumes in the post-therapy scan. The algorithm uses the pre-therapy scan and its meningioma delineation to initialize an extended Chan-Vese active contour method and as a strong patient-specific intensity and shape prior for the post-therapy scan meningioma segmentation. The algorithm is automatic, obviates the need for independent tumor localization and segmentation initialization, and incorporates the same tumor delineation criteria in both the pre- and post-therapy scans. Our experimental results on retrospective pre- and post-therapy scans with a total of 32 meningiomas with volume ranges 0.4-26.5 cm[Formula: see text] yield a Dice coefficient of [Formula: see text]% with respect to ground-truth delineations in post-therapy scans created by two clinicians. These results indicate a high correspondence to the ground-truth delineations. Our algorithm yields more reliable and accurate tumor volume change measurements than other stand-alone segmentation methods. It may be a useful tool for quantitative meningioma prognosis evaluation after SRS.

Safety of multiple stereotactic radiosurgery treatments for multiple brain lesions.

PubMed

Hillard, Virany H; Shih, Lynn L; Chin, Shing; Moorthy, Chitti R; Benzil, Deborah L

2003-07-01

Stereotactic radiosurgery (SRS) is a widely used therapy for multiple brain lesions, and studies have clearly established the safety and efficacy of single-dose SRS. However, as patient survival has increased, the recurrence of tumors and the development of metastases to new sites within the brain have made it desirable to repeat treatments over time. The cumulative toxicity of multi-isocenter, multiple treatments has not been well defined. We have retrospectively studied 10 patients who received multiple SRS treatments for multiple brain lesions to assess the cumulative toxicity of these treatments. In a retrospective review of all patients treated with SRS using the X-knife (Radionics, Burlington, MA) at Westchester Medical Center/New York Medical College between December 1995 and December 2000, 10 patients were identified who received at least two treatments to at least 3 isocenters and had a minimum follow-up period of 6 months. Image fusion technique was used to determine cumulative doses to targeted lesions, whole brain and critical brain structures. Toxicities and complications were identified by chart and radiological review. The average of the maximum doses (cGy) to a point within the whole brain was 2402 (range 1617-3953); to the brainstem, 1059 (range 48-4126); to the right optic nerve, 223 (range 14-1012); to the left optic nerve, 159 (range 17-475); and to the optic chiasm, 219 (range 15-909). There were no focal neurological toxicities, including visual disturbances, cranial nerve palsies, or ataxia in any of the 10 patients. There were also no global toxicities, including cognitive decline or secondary tumors. Only one patient developed seizures that were difficult to control in association with radiation necrosis. Multiple SRS treatments at the cumulative doses used in our study are a safe therapy for patients with multiple brain lesions.

TU-H-BRC-05: Stereotactic Radiosurgery Optimized with Orthovoltage Beams

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

Fagerstrom, J; Culberson, W; Bender, E

2016-06-15

Purpose: To achieve improved stereotactic radiosurgery (SRS) dose distributions using orthovoltage energy fluence modulation with inverse planning optimization techniques. Methods: A pencil beam model was used to calculate dose distributions from the institution’s orthovoltage unit at 250 kVp. Kernels for the model were derived using Monte Carlo methods as well as measurements with radiochromic film. The orthovoltage photon spectra, modulated by varying thicknesses of attenuating material, were approximated using open-source software. A genetic algorithm search heuristic routine was used to optimize added tungsten filtration thicknesses to approach rectangular function dose distributions at depth. Optimizations were performed for depths of 2.5,more » 5.0, and 7.5 cm, with cone sizes of 8, 10, and 12 mm. Results: Circularly-symmetric tungsten filters were designed based on the results of the optimization, to modulate the orthovoltage beam across the aperture of an SRS cone collimator. For each depth and cone size combination examined, the beam flatness and 80–20% and 90–10% penumbrae were calculated for both standard, open cone-collimated beams as well as for the optimized, filtered beams. For all configurations tested, the modulated beams were able to achieve improved penumbra widths and flatness statistics at depth, with flatness improving between 33 and 52%, and penumbrae improving between 18 and 25% for the modulated beams compared to the unmodulated beams. Conclusion: A methodology has been described that may be used to optimize the spatial distribution of added filtration material in an orthovoltage SRS beam to result in dose distributions at depth with improved flatness and penumbrae compared to standard open cones. This work provides the mathematical foundation for a novel, orthovoltage energy fluence-modulated SRS system.« less

Stereotactic radiosurgery alone for multiple brain metastases? A review of clinical and technical issues

PubMed Central

Ruschin, Mark; Ma, Lijun; Verbakel, Wilko; Larson, David; Brown, Paul D.

2017-01-01

Abstract Over the past three decades several randomized trials have enabled evidence-based practice for patients presenting with limited brain metastases. These trials have focused on the role of surgery or stereotactic radiosurgery (SRS) with or without whole brain radiation therapy (WBRT). As a result, it is clear that local control should be optimized with surgery or SRS in patients with optimal prognostic factors presenting with up to 4 brain metastases. The routine use of adjuvant WBRT remains debatable, as although greater distant brain control rates are observed, there is no impact on survival, and modern outcomes suggest adverse effects from WBRT on patient cognition and quality of life. With dramatic technologic advances in radiation oncology facilitating the adoption of SRS into mainstream practice, the optimal management of patients with multiple brain metastases is now being put forward. Practice is evolving to SRS alone in these patients despite a lack of level 1 evidence to support a clinical departure from WBRT. The purpose of this review is to summarize the current state of the evidence for patients presenting with limited and multiple metastases, and to present an in-depth analysis of the technology and dosimetric issues specific to the treatment of multiple metastases. PMID:28380635

Combining stereotactic angiography and 3D time-of-flight magnetic resonance angiography in treatment planning for arteriovenous malformation radiosurgery.

PubMed

Bednarz, G; Downes, B; Werner-Wasik, M; Rosenwasser, R H

2000-03-15

This study was initiated to evaluate the advantages of using three-dimensional time-of-flight magnetic resonance angiography (3D TOF MRA), as an adjuvant to conventional stereotactic angiography, in obtaining three-dimensional information about an arteriovenous malformation (AVM) nidus and in optimizing radiosurgical treatment plans. Following angiography, contrast-enhanced MRI and MRA studies were obtained in 22 consecutive patients undergoing Gamma Knife radiosurgery for AVM. A treatment plan was designed, based on the angiograms and modified as necessary, using the information provided by MRA. The quantitative analysis involved calculation of the ratio of the treated volume to the MRA nidus volume (the tissue volume ratio [TVR]) for the initial and final treatment plans. In 12 cases (55%), the initial treatment plans were modified after including the MRA information in the treatment planning process. The mean TVR for the angiogram-based plans was 1.63 (range 1.17-2.17). The mean coverage of the MRA nidus by the angiogram-based plans was 93% (range 73-99%). The mean MRA nidus volume was 2.4 cc (range 0. 6-5.3 cc). The MRA-based modifications resulted in increased conformity with the mean TVR of 1.46 (range 1.20-1.74). These modifications were caused by MRA revealing irregular nidi and/or vascular components superimposed on the angiographic projections of the nidi. In a number of cases, the information from MRA was essential in defining the nidus when the projections of the angiographic outlines showed different superior and/or inferior extent of the nidus. In two cases, MRA revealed irregular nidi, correlating well with the angiograms and showed that the angiographically acceptable plans undertreated 27% of the MRA nidus in one case and 18% of the nidus in the other case. In the remaining 10 cases (45%), both MRI and MRA failed to detect the nidus due to surgical clip artifacts and the presence of embolizing glue. The 3D TOF MRA provided information on irregular

Technical Note: Construction of heterogeneous head phantom for quality control in stereotactic radiosurgery.

PubMed

Najafi, Mohsen; Teimouri, Javad; Shirazi, Alireza; Geraily, Ghazale; Esfahani, Mahbod; Shafaei, Mostafa

2017-10-01

Stereotactic radiosurgery is a high precision modality for conformally delivering high doses of radiation to the brain lesion with a large dose volume. Several studies for the quality control of this technique were performed to measure the dose delivered to the target with a homogenous head phantom and some dosimeters. Some studies were also performed with one or two instances of heterogeneity in the head phantom to measure the dose delivered to the target. But these studies assumed the head as a sphere and simple shape heterogeneity. The construction of an adult human head phantom with the same size, shape, and real inhomogeneity as an adult human head is needed. Only then is measuring the accurate dose delivered to the area of interest and comparison with the calculated dose possible. According to the ICRU Report 44, polytetrafluoroethylene (PTFE) and methyl methacrylate were selected as a bone and soft tissue, respectively. A set of computed tomography (CT) scans from a standard human head were taken, and simplification of the CT images was used to design the layers of the phantom. The parts of each slice were cut and attached together. Tests of density and CT number were done to compare the material of the phantom with tissues of the head. The dose delivered to the target was measured with an EBT3 film. The density of the PTFE and Plexiglas that were inserted in the phantom are in good agreement with bone and soft tissue. Also, the CT numbers of these materials have a low difference. The dose distribution from the EBT3 film and the treatment planning system is similar. The constructed phantom with a size and inhomogeneity like an adult human head is suitable to measure the dose delivered to the area of interest. It also helps make an accurate comparison with the calculated dose by the treatment planning system. By using this phantom, the actual dose delivered to the target was obtained. This anthropomorphic head phantom can be used in other modalities of

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 ...

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

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.

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.

Histology-Stratified Tumor Control and Patient Survival After Stereotactic Radiosurgery for Pineal Region Tumors: A Report From the International Gamma Knife Research Foundation.

PubMed

Iorio-Morin, Christian; Kano, Hideyuki; Huang, Marshall; Lunsford, L Dade; Simonová, Gabriela; Liscak, Roman; Cohen-Inbar, Or; Sheehan, Jason; Lee, Cheng-Chia; Wu, Hsiu-Mei; Mathieu, David

2017-11-01

Pineal region tumors represent a rare and histologically diverse group of lesions. Few studies are available to guide management and the outcomes after stereotactic radiosurgery (SRS). Patients who underwent SRS for a pineal region tumor and for whom at least 6 months of imaging follow-up was available were retrospectively assessed in 5 centers. Data were collected from the medical record and histology level analyses were performed, including actuarial tumor control and survival analyses. A total of 70 patients were treated between 1989 and 2014 with a median follow-up of 47 months. Diagnoses were pineocytoma (37%), pineoblastoma (19%), pineal parenchymal tumor of intermediate differentiation (10%), papillary tumor of the pineal region (9%), germinoma (7%), teratoma (3%), embryonal carcinoma (1%), and unknown (14%). Median prescription dose was 15 Gy at the 50% isodose line. Actuarial local control and survival rates were 81% and 76% at 20 years for pineocytoma, 50% and 56% at 5 years for pineal parenchymal tumor of intermediate differentiation, 27% and 48% at 5 years for pineoblastoma, 33% and 100% at 5 years for papillary tumor of the pineal region, 80% and 80% at 20 years for germinoma, and 61% and 67% at 5 years for tumors of unknown histology. New focal neurological deficit, Parinaud syndrome, and hydrocephalus occurred in 9%, 7%, and 3% of cases, respectively. SRS is a safe modality for the management of pineal region tumors. Its specific role is highly dependent on tumor histology. As such, all efforts should be made to obtain a reliable histologic diagnosis. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed Central

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

2014-01-01

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

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

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

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.

Local control of brain metastases after stereotactic radiosurgery: the impact of whole brain radiotherapy and treatment paradigm

PubMed Central

Black, Paul J.; Page, Brandi R.; Lucas, John T.; Qasem, Shadi A.; Watabe, Kounosuke; Ruiz, Jimmy; Laxton, Adrian W.; Tatter, Stephen B.; Debinski, Waldemar; Chan, Michael D.

2016-01-01

Purpose We investigate clinical, pathologic, and treatment paradigm-related factors affecting local control of brain metastases after stereotactic radiosurgery (SRS) with or without whole brain radiotherapy (WBRT). Methods and materials Patients with brain metastases treated with SRS alone, before or after WBRT were considered to determine predictors of local failure (LF), time to failure and survival. Results Among 137 patients, 411 brain metastases were analyzed. 23% of patients received SRS alone, 51% received WBRT prior to SRS, and 26% received SRS followed by WBRT. LF occurred in 125 metastases: 63% after SRS alone, 20% after WBRT then SRS, and 22% after SRS then WBRT. Median time to local failure was significantly less after SRS alone compared to WBRT then SRS (12.1 v. 22.7 months, p=0.003). Tumor volume was significantly associated with LF (HR:5.2, p<0.001, 95% CI:3.4-7.8). Conclusions WBRT+SRS results in reduced LF. Local control was not significantly different after SRS as salvage therapy versus upfront SRS. PMID:29296433

The American Society for Therapeutic Radiology and Oncology (ASTRO) evidence-based review of the role of radiosurgery for malignant glioma

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

Tsao, May N.; Mehta, Minesh P.; Whelan, Timothy J.

2005-09-01

Purpose: To systematically review the evidence for the use of stereotactic radiosurgery or stereotactic fractionated radiation therapy in adult patients with malignant glioma. Methods: Key clinical questions to be addressed in this evidence-based review were identified. Outcomes considered were overall survival, quality of life or symptom control, brain tumor control or response and toxicity. MEDLINE (1990-2004 June Week 2), CANCERLIT (1990-2003), CINAHL (1990-2004 June Week 2), EMBASE (1990-2004 Week 25), and the Cochrane library (2004 issue 2) databases were searched using OVID. In addition, the Physician Data Query clinical trials database, the proceedings of the American Society of Clinical Oncologymore » (1997-2004), ASTRO (1997-2004), and the European Society of Therapeutic Radiology and Oncology (ESTRO) (1997-2003) were searched. Data from the literature search were reviewed and tabulated. This process included an assessment of the level of evidence. Results: For patients with newly diagnosed malignant glioma, radiosurgery as boost therapy with conventional external beam radiation was examined in one randomized trial, five prospective cohort studies, and seven retrospective series. There is Level I evidence that the use of radiosurgery boost followed by external beam radiotherapy and carmustine (BCNU) does not confer benefit with respect to overall survival, quality of life, or patterns of failure as compared with external beam radiotherapy and BCNU. There is Level I-III evidence of toxicity associated with radiosurgery boost as compared with external beam radiotherapy alone. The results of the prospective and retrospective studies may be influenced by selection bias. Radiosurgery used as salvage for recurrent or progressive malignant glioma after conventional external beam radiotherapy failure was reported in zero randomized trials, three prospective cohort studies, and five retrospective series. The available data are sparse and insufficient to make

Stereotactic Fractionated Radiotherapy and LINAC Radiosurgery in the Treatment of Vestibular Schwannoma-Report About Both Stereotactic Methods From a Single Institution

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

Kopp, Christine, E-mail: Christine.Kopp@lrz.tu-muenchen.de; Fauser, Claudius; Mueller, Axel

2011-08-01

Purpose: To evaluate tumor control and side effects associated with radiosurgery (RS) and stereotactic fractionated radiotherapy (SFR) for vestibular schwannomas (VSs) in a group of patients treated at the same institution. Methods and Materials: Between May 1997 and June 2007, 115 consecutive cases of VS were treated in our department. The SFR group (47 patients), including larger tumors (maximum diameter >1.5 cm), received a total dose of 54 Gy at 1.8 Gy per fraction. The RS group (68 patients, maximum diameter <1.5 cm) received a total dose of 12 Gy at the 100% isodose. Evaluation included serial imaging tests (magneticmore » resonance imaging) and neurologic and functional hearing examinations. Results: The tumor control rate was 97.9% in the SFR group for a mean follow-up time of 32.1 months and 98.5% in the RS group for a mean follow-up time of 30.1 months. Hearing function was preserved after RS in 85% of the patients and after SFR in 79%. Facial and trigeminal nerve function remained mostly unaffected after SFR. After RS, new trigeminal neuropathy occurred in 9 of 68 patients (13%). Conclusions: A high tumor control rate and low number of side effects are registered after SFR and RS of VS. These results confirm that considering tumor diameter, both RS and SFR are good treatment modalities for VS.« less

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

PubMed

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

2018-05-19

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

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.

Determination of gonad doses during robotic stereotactic radiosurgery for various tumor sites

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

Zorlu, Faruk; Dugel, Gozde; Ozyigit, Gokhan

Purpose: The authors evaluated the absorbed dose received by the gonads during robotic stereotactic radiosurgery (SRS) for the treatment of different tumor localizations. Methods: The authors measured the gonad doses during the treatment of head and neck, thoracic, abdominal, or pelvic tumors in both RANDO phantom and actual patients. The computerized tomography images were transferred to the treatment planning system. The contours of tumor and critical organs were delineated on each slice, and treatment plans were generated. Measurements for gonad doses were taken from the geometric projection of the ovary onto the skin for female patients, and from the scrotalmore » skin for male patients by attaching films and Thermoluminescent dosimeters (TLDs). SRS was delivered with CyberKnife (Accuray Inc., Sunnyvale, CA). Results: The median gonadal doses with TLD and film dosimeter in actual patients were 0.19 Gy (range, 0.035-2.71 Gy) and 0.34 Gy (range, 0.066-3.18 Gy), respectively. In the RANDO phantom, the median ovarian doses with TLD and film dosimeter were 0.08 Gy (range, 0.03-0.159 Gy) and 0.05 Gy (range, 0.015-0.13 Gy), respectively. In the RANDO phantom, the median testicular doses with TLD and film dosimeter were 0.134 Gy (range 0.056-1.97 Gy) and 0.306 Gy (range, 0.065-2.25 Gy). Conclusions: Gonad doses are below sterility threshold in robotic SRS for different tumor localizations. However, particular attention should be given to gonads during robotic SRS for pelvic tumors.« less

Quality of search strategies reported in systematic reviews published in stereotactic radiosurgery.

PubMed

Faggion, Clovis M; Wu, Yun-Chun; Tu, Yu-Kang; Wasiak, Jason

2016-06-01

Systematic reviews require comprehensive literature search strategies to avoid publication bias. This study aimed to assess and evaluate the reporting quality of search strategies within systematic reviews published in the field of stereotactic radiosurgery (SRS). Three electronic databases (Ovid MEDLINE(®), Ovid EMBASE(®) and the Cochrane Library) were searched to identify systematic reviews addressing SRS interventions, with the last search performed in October 2014. Manual searches of the reference lists of included systematic reviews were conducted. The search strategies of the included systematic reviews were assessed using a standardized nine-question form based on the Cochrane Collaboration guidelines and Assessment of Multiple Systematic Reviews checklist. Multiple linear regression analyses were performed to identify the important predictors of search quality. A total of 85 systematic reviews were included. The median quality score of search strategies was 2 (interquartile range = 2). Whilst 89% of systematic reviews reported the use of search terms, only 14% of systematic reviews reported searching the grey literature. Multiple linear regression analyses identified publication year (continuous variable), meta-analysis performance and journal impact factor (continuous variable) as predictors of higher mean quality scores. This study identified the urgent need to improve the quality of search strategies within systematic reviews published in the field of SRS. This study is the first to address how authors performed searches to select clinical studies for inclusion in their systematic reviews. Comprehensive and well-implemented search strategies are pivotal to reduce the chance of publication bias and consequently generate more reliable systematic review findings.

Microsurgery Versus Stereotactic Radiosurgery for Brain Arteriovenous Malformations: A Matched Cohort Study.

PubMed

Chen, Ching-Jen; Ding, Dale; Wang, Tony R; Buell, Thomas J; Ilyas, Adeel; Ironside, Natasha; Lee, Cheng-Chia; Kalani, M Yashar; Park, Min S; Liu, Kenneth C; Sheehan, Jason P

2018-05-12

Microsurgery (MS) and stereotactic radiosurgery (SRS) remain the preferred interventions for the curative treatment of brain arteriovenous malformations (AVM), but their relative efficacy remains incompletely defined. To compare the outcomes of MS to SRS for AVMs through a retrospective, matched cohort study. We evaluated institutional databases of AVM patients who underwent MS and SRS. MS-treated patients were matched, in a 1:1 ratio based on patient and AVM characteristics, to SRS-treated patients. Statistical analyses were performed to compare outcomes data between the 2 cohorts. The primary outcome was defined as AVM obliteration without a new permanent neurological deficit. The matched MS and SRS cohorts were each comprised of 59 patients. Both radiological (85 vs 11 mo; P < .001) and clinical (92 vs 12 mo; P < .001) follow-up were significantly longer for the SRS cohort. The primary outcome was achieved in 69% of each cohort. The MS cohort had a significantly higher obliteration rate (98% vs 72%; P = .001), but also had a significantly higher rate of new permanent deficit (31% vs 10%; P = .011). The posttreatment hemorrhage rate was significantly higher for the SRS cohort (10% for SRS vs 0% for MS; P = .027). In subgroup analyses of ruptured and unruptured AVMs, no significant differences between the primary outcomes were observed. For patients with comparable AVMs, MS and SRS afford similar rates of deficit-free obliteration. Nidal obliteration is more frequently achieved with MS, but this intervention also incurs a greater risk of new permanent neurological deficit.

Postoperative stereotactic radiosurgery for resected brain metastases: A comparison of outcomes for large resection cavities.

PubMed

Zhong, Jim; Ferris, Matthew J; Switchenko, Jeffrey; Press, Robert H; Buchwald, Zachary; Olson, Jeffrey J; Eaton, Bree R; Curran, Walter J; Shu, Hui-Kuo G; Crocker, Ian R; Patel, Kirtesh R

Although historical trials have established the role of surgical resection followed by whole brain irradiation (WBRT) for brain metastases, WBRT has recently been shown to cause significant neurocognitive decline. Many practitioners have employed postoperative stereotactic radiosurgery (SRS) to tumor resection cavities to increase local control without causing significant neurocognitive sequelae. However, studies analyzing outcomes of large brain metastases treated with resection and postoperative SRS are lacking. Here we compare outcomes in patients with large brain metastases >4 cm to those with smaller metastases ≤4 cm treated with surgical resection followed by SRS to the resection cavity. Consecutive patients with brain metastases treated at our institution with surgical resection and postoperative SRS were retrospectively reviewed. Patients were stratified into ≤4 cm and >4 cm cohorts based on preoperative maximal tumor dimension. Cumulative incidence of local failure, radiation necrosis, and death were analyzed for the 2 cohorts using a competing-risk model, defined as the time from SRS treatment date to the measured event, death, or last follow-up. A total of 117 consecutive cases were identified. Of these patients, 90 (77%) had preoperative tumors ≤4 cm, and 27 (23%) >4 cm in greatest dimension. The only significant baseline difference between the 2 groups was a higher proportion of patients who underwent gross total resection in the ≤4 cm compared with the >4 cm cohort, 76% versus 48%, respectively (P <.01). The 1-year rates of local failure, radiation necrosis, and overall survival for the ≤4 cm and >4 cm cohorts were 12.3% and 16.0%, 26.9% and 28.4%, and 80.6% and 67.6%, respectively (all P >.05). The rates of local failure and radiation necrosis were not statistically different on multivariable analysis based on tumor size. Brain metastases >4 cm in largest dimension managed by resection and radiosurgery to the tumor cavity have promising

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

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

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.

Predictors of Individual Tumor Local Control After Stereotactic Radiosurgery for Non-Small Cell Lung Cancer Brain Metastases

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

Garsa, Adam A.; Badiyan, Shahed N.; DeWees, Todd

2014-10-01

Purpose: To evaluate local control rates and predictors of individual tumor local control for brain metastases from non-small cell lung cancer (NSCLC) treated with stereotactic radiosurgery (SRS). Methods and Materials: Between June 1998 and May 2011, 401 brain metastases in 228 patients were treated with Gamma Knife single-fraction SRS. Local failure was defined as an increase in lesion size after SRS. Local control was estimated using the Kaplan-Meier method. The Cox proportional hazards model was used for univariate and multivariate analysis. Receiver operating characteristic analysis was used to identify an optimal cutpoint for conformality index relative to local control. Amore » P value <.05 was considered statistically significant. Results: Median age was 60 years (range, 27-84 years). There were 66 cerebellar metastases (16%) and 335 supratentorial metastases (84%). The median prescription dose was 20 Gy (range, 14-24 Gy). Median overall survival from time of SRS was 12.1 months. The estimated local control at 12 months was 74%. On multivariate analysis, cerebellar location (hazard ratio [HR] 1.94, P=.009), larger tumor volume (HR 1.09, P<.001), and lower conformality (HR 0.700, P=.044) were significant independent predictors of local failure. Conformality index cutpoints of 1.4-1.9 were predictive of local control, whereas a cutpoint of 1.75 was the most predictive (P=.001). The adjusted Kaplan-Meier 1-year local control for conformality index ≥1.75 was 84% versus 69% for conformality index <1.75, controlling for tumor volume and location. The 1-year adjusted local control for cerebellar lesions was 60%, compared with 77% for supratentorial lesions, controlling for tumor volume and conformality index. Conclusions: Cerebellar tumor location, lower conformality index, and larger tumor volume were significant independent predictors of local failure after SRS for brain metastases from NSCLC. These results warrant further investigation in a

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.

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.

Internal validation of the prognostic index for spine metastasis (PRISM) for stratifying survival in patients treated with spinal stereotactic radiosurgery.

PubMed

Jensen, Garrett; Tang, Chad; Hess, Kenneth R; Bishop, Andrew J; Pan, Hubert Y; Li, Jing; Yang, James N; Tannir, Nizar M; Amini, Behrang; Tatsui, Claudio; Rhines, Laurence; Brown, Paul D; Ghia, Amol J

2017-01-01

We sought to validate the Prognostic Index for Spinal Metastases (PRISM), a scoring system that stratifies patients into subgroups by overall survival.Methods and materials: The PRISM was previously created from multivariate Cox regression with patients enrolled in prospective single institution trials of stereotactic spine radiosurgery (SSRS) for spinal metastasis. We assess model calibration and discrimination within a validation cohort of patients treated off-trial with SSRS for metastatic disease at the same institution. The training and validation cohorts consisted of 205 and 249 patients respectively. Similar survival trends were shown in the 4 PRISM. Survival was significantly different between PRISM subgroups (P<0.0001). C-index for the validation cohort was 0.68 after stratification into subgroups. We internally validated the PRISM with patients treated off-protocol, demonstrating that it can distinguish subgroups by survival, which will be useful for individualizing treatment of spinal metastases and stratifying patients for clinical trials.

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.

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.

Robotic real-time translational and rotational head motion correction during frameless stereotactic radiosurgery

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

Liu, Xinmin; Belcher, Andrew H.; Grelewicz, Zachary

Purpose: To develop a control system to correct both translational and rotational head motion deviations in real-time during frameless stereotactic radiosurgery (SRS). Methods: A novel feedback control with a feed-forward algorithm was utilized to correct for the coupling of translation and rotation present in serial kinematic robotic systems. Input parameters for the algorithm include the real-time 6DOF target position, the frame pitch pivot point to target distance constant, and the translational and angular Linac beam off (gating) tolerance constants for patient safety. Testing of the algorithm was done using a 4D (XY Z + pitch) robotic stage, an infrared headmore » position sensing unit and a control computer. The measured head position signal was processed and a resulting command was sent to the interface of a four-axis motor controller, through which four stepper motors were driven to perform motion compensation. Results: The control of the translation of a brain target was decoupled with the control of the rotation. For a phantom study, the corrected position was within a translational displacement of 0.35 mm and a pitch displacement of 0.15° 100% of the time. For a volunteer study, the corrected position was within displacements of 0.4 mm and 0.2° over 98.5% of the time, while it was 10.7% without correction. Conclusions: The authors report a control design approach for both translational and rotational head motion correction. The experiments demonstrated that control performance of the 4D robotic stage meets the submillimeter and subdegree accuracy required by SRS.« less

A Score to Identify Patients with Brain Metastases from Colorectal Cancer Who May Benefit from Whole-brain Radiotherapy in Addition to Stereotactic Radiosurgery/Radiotherapy.

PubMed

Rades, Dirk; Dziggel, Liesa; Blanck, Oliver; Gebauer, Niklas; Bartscht, Tobias; Schild, Steven E

2018-05-01

To design a tool to predict the probability of new cerebral lesions after stereotactic radiosurgery/radiotherapy for patients with 1-3 brain metastases from colorectal cancer. In 21 patients, nine factors were evaluated for freedom from new brain metastases, namely age, gender, Karnofsky performance score (KPS), tumor type, number, maximum total diameter of all lesions and sites of cerebral lesions, extra-cranial metastases, and time from cancer diagnosis to irradiation. Freedom from new lesions was positively associated with KPS of 90-100 (p=0.013); maximum total diameter ≤15 mm showed a trend for positive association (p=0.09). Points were assigned as: KPS 70-80=1 point, KPS 90-100=2 points, maximum diameter ≤15 mm=2 points and maximum diameter >15 mm=1 point. Six-month rates of freedom from new lesions were 29%, 45% and 100% for those with total scores of 2, 3 and 4 points, respectively, with corresponding 12-month rates of 0%, 45% and 100% (p=0.027). This study identified three risk groups regarding new brain metastases after stereotactic irradiation. Patients with 2 points could benefit from additional whole-brain radiotherapy. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

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

Design of a modulated orthovoltage stereotactic radiosurgery system.

PubMed

Fagerstrom, Jessica M; Bender, Edward T; Lawless, Michael J; Culberson, Wesley S

2017-07-01

To achieve stereotactic radiosurgery (SRS) dose distributions with sharp gradients using orthovoltage energy fluence modulation with inverse planning optimization techniques. A pencil beam model was used to calculate dose distributions from an orthovoltage unit at 250 kVp. Kernels for the model were derived using Monte Carlo methods. A Genetic Algorithm search heuristic was used to optimize the spatial distribution of added tungsten filtration to achieve dose distributions with sharp dose gradients. Optimizations were performed for depths of 2.5, 5.0, and 7.5 cm, with cone sizes of 5, 6, 8, and 10 mm. In addition to the beam profiles, 4π isocentric irradiation geometries were modeled to examine dose at 0.07 mm depth, a representative skin depth, for the low energy beams. Profiles from 4π irradiations of a constant target volume, assuming maximally conformal coverage, were compared. Finally, dose deposition in bone compared to tissue in this energy range was examined. Based on the results of the optimization, circularly symmetric tungsten filters were designed to modulate the orthovoltage beam across the apertures of SRS cone collimators. For each depth and cone size combination examined, the beam flatness and 80-20% and 90-10% penumbrae were calculated for both standard, open cone-collimated beams as well as for optimized, filtered beams. For all configurations tested, the modulated beam profiles had decreased penumbra widths and flatness statistics at depth. Profiles for the optimized, filtered orthovoltage beams also offered decreases in these metrics compared to measured linear accelerator cone-based SRS profiles. The dose at 0.07 mm depth in the 4π isocentric irradiation geometries was higher for the modulated beams compared to unmodulated beams; however, the modulated dose at 0.07 mm depth remained <0.025% of the central, maximum dose. The 4π profiles irradiating a constant target volume showed improved statistics for the modulated, filtered

Time-of-flight magnetic resonance angiography imaging of a residual arteriovenous malformation nidus after Onyx embolization for stereotactic radiosurgery planning. Technical note.

PubMed

Loy, David N; Rich, Keith M; Simpson, Joseph; Dorward, Ian; Santanam, Lakshmi; Derdeyn, Colin P

2009-05-01

This report demonstrates that time-of-flight (TOF) MR angiography is a useful adjunct for planning stereotactic radiosurgery (SRS) of large arteriovenous malformations (AVMs) after staged embolization with Onyx. Onyx (ethylene vinyl copolymer), a recently approved liquid embolic agent, has been increasingly used to exclude portions of large AVMs from the parent circulation prior to SRS. Limiting SRS to regions of persistent arteriovenous shunting and excluding regions eliminated by embolization may reduce unnecessary radiation doses to eloquent brain structures. However, SRS dosimetry planning presents unique challenges after Onyx embolization because it creates extensive artifacts on CT scans, and it cannot be delineated from untreated nidus on standard MR sequences. During the radiosurgery procedure, MR images were obtained using a GE Signa 1.5-T unit. Standard axial T2 fast spin echo high-resolution images (TR 3000 msec, TE 108 msec, slice thickness 2.5 mm) were generated for optimal visualization of brain tissue and AVM flow voids. The 3D TOF MR angiography images of the circle of Willis and vertebral arteries were subsequently obtained to visualize AVM regions embolized with Onyx (TR 37 msec, TE 6.9 msec, flip angle 20 degrees). Adjunct TOF MR angiography images demonstrated excellent contrast between nidus embolized with Onyx and regions of persistent arteriovenous shunting within a large AVM prior to SRS. Additional information derived from these sequences resulted in substantial adjustments to the treatment plan and an overall reduction in the treated tissue volume.

Impact of 2-staged stereotactic radiosurgery for treatment of brain metastases ≥ 2 cm.

PubMed

Angelov, Lilyana; Mohammadi, Alireza M; Bennett, Elizabeth E; Abbassy, Mahmoud; Elson, Paul; Chao, Samuel T; Montgomery, Joshua S; Habboub, Ghaith; Vogelbaum, Michael A; Suh, John H; Murphy, Erin S; Ahluwalia, Manmeet S; Nagel, Sean J; Barnett, Gene H

2017-09-22

OBJECTIVE Stereotactic radiosurgery (SRS) is the primary modality for treating brain metastases. However, effective radiosurgical control of brain metastases ≥ 2 cm in maximum diameter remains challenging and is associated with suboptimal local control (LC) rates of 37%-62% and an increased risk of treatment-related toxicity. To enhance LC while limiting adverse effects (AEs) of radiation in these patients, a dose-dense treatment regimen using 2-staged SRS (2-SSRS) was used. The objective of this study was to evaluate the efficacy and toxicity of this treatment strategy. METHODS Fifty-four patients (with 63 brain metastases ≥ 2 cm) treated with 2-SSRS were evaluated as part of an institutional review board-approved retrospective review. Volumetric measurements at first-stage stereotactic radiosurgery (first SSRS) and second-stage SRS (second SSRS) treatments and on follow-up imaging studies were determined. In addition to patient demographic data and tumor characteristics, the study evaluated 3 primary outcomes: 1) response at first follow-up MRI, 2) time to local progression (TTP), and 3) overall survival (OS) with 2-SSRS. Response was analyzed using methods for binary data, TTP was analyzed using competing-risks methods to account for patients who died without disease progression, and OS was analyzed using conventional time-to-event methods. When needed, analyses accounted for multiple lesions in the same patient. RESULTS Among 54 patients, 46 (85%) had 1 brain metastasis treated with 2-SSRS, 7 patients (13%) had 2 brain metastases concurrently treated with 2-SSRS, and 1 patient underwent 2-SSRS for 3 concurrent brain metastases ≥ 2 cm. The median age was 63 years (range 23-83 years), 23 patients (43%) had non-small cell lung cancer, and 14 patients (26%) had radioresistant tumors (renal or melanoma). The median doses at first and second SSRS were 15 Gy (range 12-18 Gy) and 15 Gy (range 12-15 Gy), respectively. The median duration between stages was 34 days

Salvage stereotactic radiosurgery for breast cancer brain metastases: outcomes and prognostic factors.

PubMed

Kelly, Paul J; Lin, Nancy U; Claus, Elizabeth B; Quant, Eudocia C; Weiss, Stephanie E; Alexander, Brian M

2012-04-15

Salvage stereotactic radiosurgery (SRS) is often considered in breast cancer patients previously treated for brain metastases. The goal of this study was to analyze clinical outcomes and prognostic factors for survival in the salvage setting. The authors retrospectively examined 79 consecutive breast cancer patients who received salvage SRS (interval of >3 months after initial therapy), 76 of whom (96%) received prior whole-brain radiation therapy. Overall survival (OS) and central nervous system (CNS) progression-free survival rates were calculated from the date of SRS using the Kaplan-Meier method. Prognostic factors were evaluated using the Cox proportional hazards model. Median age was 50.5 years. Fifty-eight percent of this population was estrogen receptor positive, 62% was HER2 positive, and 10% was triple negative. At the time of SRS, 95% had extracranial metastases, with 81% of extracranial metastases at other visceral sites (lung/pleura/liver). Forty-eight percent had stable extracranial disease. Median interval from initial brain metastases therapy to SRS was 8.4 months. Median CNS progression-free survival after SRS was 5.7 months (interquartile range [IQR], 3.6-11 months), and median OS was 9.8 months (IQR, 3.8-18 months). Eighty-two percent of evaluable patients received further systemic therapy after SRS. HER2 status (adjusted hazard ratio [HR], 2.4; P = .008) and extracranial disease status (adjusted HR, 2.7; P = .004) were significant prognostic factors for survival on multivariate analysis. In patients with good Karnofsky performance status, salvage SRS for breast cancer brain metastases is a reasonable treatment option, given an associated median survival in excess of 9 months. Furthermore, patients with HER2-positive tumors at diagnosis or stable extracranial disease at the time of SRS have an improved clinical course, with median survival of >1 year. Copyright © 2011 American Cancer Society.

Long-Term Outcomes of Stereotactic Radiosurgery for Treatment of Cavernous Sinus Meningiomas

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

Santos, Marcos Antonio dos, E-mail: marcosrxt@gmail.com; Bustos Perez de Salcedo, Jose; Gutierrez Diaz, Jose Angel

2011-12-01

Purpose: Patients with cavernous sinus meningiomas (CSM) have an elevated risk of surgical morbidity and mortality. Recurrence is often observed after partial resection. Stereotactic radiosurgery (SRS), either alone or combined with surgery, represents an important advance in CSM management, but long-term results are lacking. Methods and Materials: A total of 88 CSM patients, treated from January 1991 to December 2005, were retrospectively reviewed. The mean follow-up was 86.8 months (range, 17.1-179.4 months). Among the patients, 22 were followed for more than 10 years. There was a female predominance (84.1%). The age varied from 16 to 90 years (mean, 51.6). Inmore » all, 47 patients (53.4%) received SRS alone, and 41 patients (46.6%) had undergone surgery before SRS. A dose of 14 Gy was prescribed to isodose curves from 50% to 90%. In 25 patients (28.4%), as a result of the proximity to organs at risk, the prescribed dose did not completely cover the target. Results: After SRS, 65 (73.8%) patients presented with tumor volume reduction; 14 (15.9%) remained stable, and 9 (10.2%) had tumor progression. The progression-free survival was 92.5% at 5 years, and 82.5% at 10 years. Age, sex, maximal diameter of the treated tumor, previous surgery, and complete target coverage did not show significant associations with prognosis. Among the 88 treated patients, 17 experienced morbidity that was related to SRS, and 6 of these patients spontaneously recovered. Conclusions: SRS is an effective and safe treatment for CSM, feasible either in the primary or the postsurgical setting. Incomplete coverage of the target did not worsen outcomes. More than 80% of the patients remained free of disease progression during long-term follow-up.« less

Concurrent Stereotactic Radiosurgery and Bevacizumab in Recurrent Malignant Gliomas: A Prospective Trial

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

Cabrera, Alvin R.; Cuneo, Kyle C.; Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan

2013-08-01

Purpose: Virtually all patients with malignant glioma (MG) eventually recur. This study evaluates the safety of concurrent stereotactic radiosurgery (SRS) and bevacizumab (BVZ), an antiangiogenic agent, in treatment of recurrent MG. Methods and Materials: Fifteen patients with recurrent MG, treated at initial diagnosis with surgery and adjuvant radiation therapy/temozolomide and then at least 1 salvage chemotherapy regimen, were enrolled in this prospective trial. Lesions <3 cm in diameter were treated in a single fraction, whereas those 3 to 5 cm in diameter received 5 5-Gy fractions. BVZ was administered immediately before SRS and 2 weeks later. Neurocognitive testing (Mini-Mental Statusmore » Exam, Trail Making Test A/B), Functional Assessment of Cancer Therapy-Brain (FACT-Br) quality-of-life assessment, physical exam, and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) were performed immediately before SRS and 1 week and 2 months following completion of SRS. The primary endpoint was central nervous system (CNS) toxicity. Secondary endpoints included survival, quality of life, microvascular properties as measured by DCE-MRI, steroid usage, and performance status. Results: One grade 3 (severe headache) and 2 grade 2 CNS toxicities were observed. No patients experienced grade 4 to 5 toxicity or intracranial hemorrhage. Neurocognition, quality of life, and Karnofsky performance status did not change significantly with treatment. DCE-MRI results suggest a significant decline in tumor perfusion and permeability 1 week after SRS and further decline by 2 months. Conclusions: Treatment of recurrent MG with concurrent SRS and BVZ was not associated with excessive toxicity in this prospective trial. A randomized trial of concurrent SRS/BVZ versus conventional salvage therapy is needed to establish the efficacy of this approach.« less

Hybrid surgery-radiosurgery therapy for metastatic epidural spinal cord compression: A prospective evaluation using patient-reported outcomes.

PubMed

Barzilai, Ori; Amato, Mary-Kate; McLaughlin, Lily; Reiner, Anne S; Ogilvie, Shahiba Q; Lis, Eric; Yamada, Yoshiya; Bilsky, Mark H; Laufer, Ilya

2018-05-01

Patient-reported outcomes (PRO) represent an important measure of cancer therapy effect. For patients with metastatic epidural spinal cord compression (MESCC), hybrid therapy using separation surgery and stereotactic radiosurgery preserves neurologic function and provides tumor control. There is currently a paucity of data reporting PRO after such combined modality therapy for MESCC. Delineation of hybrid surgery-radiosurgery therapy effect on PRO validates the hybrid approach as an effective therapy resulting in meaningful symptom relief. Brief Pain Inventory (BPI) and MD Anderson Symptom Inventory-Spine Tumor (MDASI-SP), PROs validated in the cancer population, were prospectively collected. Patients with MESCC who underwent separation surgery followed by stereotactic radiosurgery were included. Separation surgery included a posterolateral approach without extensive cytoreductive tumor excision. A median postoperative radiosurgery dose of 2700 cGy was delivered. The change in PRO 3 months after the hybrid therapy represented the primary study outcome. Preoperative and postoperative evaluations were analyzed using the Wilcoxon signed-rank test for matched pairs. One hundred eleven patients were included. Hybrid therapy resulted in a significant reduction in the BPI items "worst" and "right now" pain ( P < .0001), and in all BPI constructs (severity, interference with daily activities, and pain experience, P < .001). The MDASI-SP demonstrated reduction in spine-specific pain severity and interference with general activity ( P < .001), along with decreased symptom interference ( P < .001). Validated PRO instruments showed that in patients with MESCC, hybrid therapy with separation surgery and radiosurgery results in a significant decrease in pain severity and symptom interference. These prospective data confirm the benefit of hybrid therapy for treatment of MESCC and should facilitate referral of patients with MESCC for surgical evaluation.

Does Stereotactic Radiosurgery Have a Role in the Management of Patients Presenting With 4 or More Brain Metastases?

PubMed

Soike, Michael H; Hughes, Ryan T; Farris, Michael; McTyre, Emory R; Cramer, Christina K; Bourland, J D; Chan, Michael D

2018-06-01

Stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) are effective treatments for management of brain metastases. Prospective trials comparing the 2 modalities in patients with fewer than 4 brain metastases demonstrate that overall survival (OS) is similar. Intracranial failure is more common after SRS, while WBRT is associated with neurocognitive decline. As technology has advanced, fewer technical obstacles remain for treating patients with 4 or more brain metastases with SRS, but level I data supporting its use are lacking. Observational prospective studies and retrospective series indicate that in patients with 4 or more brain metastases, performance status, total volume of intracranial disease, histology, and rate of development of new brain metastases predict outcomes more accurately than the number of brain metastases. It may be reasonable to initially offer SRS to some patients with 4 or more brain metastases. Initiating therapy with SRS avoids the acute and late sequelae of WBRT. Multiple phase III trials of SRS vs WBRT, both currently open or under development, are directly comparing quality of life and OS for patients with 4 or more brain metastases to help answer the question of SRS appropriateness for these patients.

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

Surgical Resection of Brain Metastases and the Risk of Leptomeningeal Recurrence in Patients Treated With Stereotactic Radiosurgery

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

Johnson, Matthew D., E-mail: Matthewjohnson@beaumont.edu; Avkshtol, Vladimir; Baschnagel, Andrew M.

Purpose: Recent prospective data have shown that patients with solitary or oligometastatic disease to the brain may be treated with upfront stereotactic radiosurgery (SRS) with deferral of whole-brain radiation therapy (WBRT). This has been extrapolated to the treatment of patients with resected lesions. The aim of this study was to assess the risk of leptomeningeal disease (LMD) in patients treated with SRS to the postsurgical resection cavity for brain metastases compared with patients treated with SRS to intact metastases. Methods and Materials: Four hundred sixty-five patients treated with SRS without upfront WBRT at a single institution were identified; 330 ofmore » these with at least 3 months' follow-up were included in this analysis. One hundred twelve patients had undergone surgical resection of at least 1 lesion before SRS compared with 218 treated for intact metastases. Time to LMD and overall survival (OS) time were estimated from date of radiosurgery, and LMD was analyzed by the use of cumulative incidence method with death as a competing risk. Univariate and multivariate analyses were performed with competing risk regression to determine whether various clinical factors predicted for LMD. Results: With a median follow-up time of 9.0 months, 39 patients (12%) experienced LMD at a median of 6.0 months after SRS. At 1 year, the cumulative incidence of LMD, with death as a competing risk, was 5.2% for the patients without surgical resection versus 16.9% for those treated with surgery (Gray test, P<.01). On multivariate analysis, prior surgical resection (P<.01) and breast cancer primary (P=.03) were significant predictors of LMD development. The median OS times for patients undergoing surgery compared with SRS alone were 12.9 and 10.6 months, respectively (log-rank P=.06). Conclusions: In patients undergoing SRS with deferral of upfront WBRT for intracranial metastatic disease, prior surgical resection and breast cancer primary are associated with

SU-G-BRB-15: Verifications of Absolute and Relative Dosimetry of a Novel Stereotactic Breast Device: GammaPodTM

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

Becker, S; Mossahebi, S; Yi, B

Purpose: A dedicated stereotactic breast radiotherapy device, GammaPod, was developed to treat early stage breast cancer. The first clinical unit was installed and commissioned at University of Maryland. We report our methodology of absolute dosimetry in multiple calibration conditions and dosimetric verifications of treatment plans produced by the system. Methods: GammaPod unit is comprised of a rotating hemi-spherical source carrier containing 36 Co-60 sources and a concentric tungsten collimator providing beams of 15 and 25 mm. Absolute dose calibration formalism was developed with modifications to AAPM protocols for unique geometry and different calibration medium (acrylic, polyethylene or liquid water). Breastmore » cup-size specific and collimator output factors were measured and verified with respect to Monte-Carlo simulations for single isocenter plans. Multiple isocenter plans were generated for various target size, location and cup-sizes in phantoms and 20 breast cancer patients images. Stereotactic mini-farmer chamber, OSL and TLD detectors as well as radio-chromic films were used for dosimetric measurements. Results: At the time of calibration (1/14/2016), absolute dose rate of the GammaPod was established to be 2.10 Gy/min in acrylic for 25 mm for sources installed in March 2011. Output factor for 15 mm collimator was measured to be 0.950. Absolute dose calibration was independently verified by IROC-Houston with a TLD/Institution ratio of 0.99. Cup size specific output measurements in liquid water for single isocenter were found to be within 3.0% of MC simulations. Point-dose measurements of multiple isocenter treatment plans were found to be within −1.0 ± 1.2 % of treatment planning system while 2-dimensional gamma analysis yielded a pass rate of 97.9 ± 2.2 % using gamma criteria of 3% and 2mm. Conclusion: The first GammaPod treatment unit for breast stereotactic radiotherapy was successfully installed, calibrated and commissioned for patient

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.

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

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

Juh, R; Han, J; Kim, C

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

Stereotactic radiotherapy following surgery for brain metastasis: Predictive factors for local control and radionecrosis.

PubMed

Doré, M; Martin, S; Delpon, G; Clément, K; Campion, L; Thillays, F

2017-02-01

To evaluate local control and adverse effects after postoperative hypofractionated stereotactic radiosurgery in patients with brain metastasis. We reviewed patients who had hypofractionated stereotactic radiosurgery (7.7Gy×3 prescribed to the 70% isodose line, with 2mm planning target volume margin) following resection from March 2008 to January 2014. The primary endpoint was local failure defined as recurrence within the surgical cavity. Secondary endpoints were distant failure rates and the occurrence of radionecrosis. Out of 95 patients, 39.2% had metastatic lesions from a non-small cell lung cancer primary tumour. The median Graded Prognostic Assessment score was 3 (48% of patients). One-year local control rates were 84%. Factors associated with improved local control were no cavity enhancement on pre-radiation MRI (P<0.00001), planning target volume less than 12cm 3 (P=0.005), Graded Prognostic Assessment score 2 or above (P=0.009). One-year distant cerebral control rates were 56%. Thirty-three percent of patients received whole brain radiation therapy. Histologically proven radionecrosis of brain tissue occurred in 7.2% of cases. The size of the preoperative lesion and the volume of healthy brain tissue receiving 21Gy (V 21 ) were both predictive of the incidence of radionecrosis (P=0.010 and 0.036, respectively). Adjuvant hypofractionated stereotactic radiosurgery to the postoperative cavity in patients with brain metastases results in excellent local control in selected patients, helps delay the use of whole brain radiation, and is associated with a relatively low risk of radionecrosis. Copyright © 2016 Société française de radiothérapie oncologique (SFRO). Published by Elsevier SAS. All rights reserved.

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.

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.

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

Prognostic Factors for Survival in Patients Treated With Stereotactic Radiosurgery for Recurrent Brain Metastases After Prior Whole Brain Radiotherapy

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

Caballero, Jorge A.; Sneed, Penny K., E-mail: psneed@radonc.ucsf.edu; Lamborn, Kathleen R.

2012-05-01

Purpose: To evaluate prognostic factors for survival after stereotactic radiosurgery (SRS) for new, progressive, or recurrent brain metastases (BM) after prior whole brain radiotherapy (WBRT). Methods and Materials: Patients treated between 1991 and 2007 with Gamma Knife SRS for BM after prior WBRT were retrospectively reviewed. Potential prognostic factors were analyzed overall and by primary site using univariate and stepwise multivariate analyses and recursive partitioning analysis, including age, Karnofsky performance status (KPS), primary tumor control, extracranial metastases, number of BM treated, total SRS target volume, and interval from WBRT to SRS. Results: A total of 310 patients were analyzed, includingmore » 90 breast, 113 non-small-cell lung, 31 small-cell lung, 42 melanoma, and 34 miscellaneous patients. The median age was 56, KPS 80, number of BM treated 3, and interval from WBRT to SRS 8.1 months; 76% had controlled primary tumor and 60% had extracranial metastases. The median survival was 8.4 months overall and 12.0 vs. 7.9 months for single vs. multiple BM treated (p = 0.001). There was no relationship between number of BM and survival after excluding single-BM patients. On multivariate analysis, favorable prognostic factors included age <50, smaller total target volume, and longer interval from WBRT to SRS in breast cancer patients; smaller number of BM, KPS >60, and controlled primary in non-small-cell lung cancer patients; and smaller total target volume in melanoma patients. Conclusions: Among patients treated with salvage SRS for BM after prior WBRT, prognostic factors appeared to vary by primary site. Although survival time was significantly longer for patients with a single BM, the median survival time of 7.9 months for patients with multiple BM seems sufficiently long for salvage SRS to appear to be worthwhile, and no evidence was found to support the use of a cutoff for number of BM appropriate for salvage SRS.« less

Hearing Outcomes After Stereotactic Radiosurgery for Unilateral Intracanalicular Vestibular Schwannomas: Implication of Transient Volume Expansion

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

Kim, Young-Hoon; Department of Neurosurgery, Seoul National University College of Medicine, Seoul; Kim, Dong Gyu, E-mail: gknife@plaza.snu.ac.kr

2013-01-01

Purpose: We evaluated the prognostic factors for hearing outcomes after stereotactic radiosurgery (SRS) for unilateral sporadic intracanalicular vestibular schwannomas (IC-VSs) as a clinical homogeneous group of VSs. Methods and Materials: Sixty consecutive patients with unilateral sporadic IC-VSs, defined as tumors in the internal acoustic canal, and serviceable hearing (Gardner-Roberson grade 1 or 2) were treated with SRS as an initial treatment. The mean tumor volume was 0.34 {+-} 0.03 cm{sup 3} (range, 0.03-1.00 cm{sup 3}), and the mean marginal dose was 12.2 {+-} 0.1 Gy (range, 11.5-13.0 Gy). The median follow-up duration was 62 months (range, 36-141 months). Results: Themore » actuarial rates of serviceable hearing preservation were 70%, 63%, and 55% at 1, 2, and 5 years after SRS, respectively. In multivariate analysis, transient volume expansion of {>=}20% from initial tumor size was a statistically significant risk factor for loss of serviceable hearing and hearing deterioration (increase of pure tone average {>=}20 dB) (odds ratio = 7.638; 95% confidence interval, 2.317-25.181; P=.001 and odds ratio = 3.507; 95% confidence interval, 1.228-10.018; P=.019, respectively). The cochlear radiation dose did not reach statistical significance. Conclusions: Transient volume expansion after SRS for VSs seems to be correlated with hearing deterioration when defined properly in a clinically homogeneous group of patients.« less

Comparison of Gafchromic EBT2 and EBT3 for patient-specific quality assurance: Cranial stereotactic radiosurgery using volumetric modulated arc therapy with multiple noncoplanar arcs

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

Fiandra, Christian; Fusella, Marco; Filippi, Andrea Riccardo

2013-08-15

Purpose: Patient-specific quality assurance in volumetric modulated arc therapy (VMAT) brain stereotactic radiosurgery raises specific issues on dosimetric procedures, mainly represented by the small radiation fields associated with the lack of lateral electronic equilibrium, the need of small detectors and the high dose delivered (up to 30 Gy). Gafchromic{sup TM} EBT2 and EBT3 films may be considered the dosimeter of choice, and the authors here provide some additional data about uniformity correction for this new generation of radiochromic films.Methods: A new analysis method using blue channel for marker dye correction was proposed for uniformity correction both for EBT2 and EBT3more » films. Symmetry, flatness, and field-width of a reference field were analyzed to provide an evaluation in a high-spatial resolution of the film uniformity for EBT3. Absolute doses were compared with thermoluminescent dosimeters (TLD) as baseline. VMAT plans with multiple noncoplanar arcs were generated with a treatment planning system on a selected pool of eleven patients with cranial lesions and then recalculated on a water-equivalent plastic phantom by Monte Carlo algorithm for patient-specific QA. 2D quantitative dose comparison parameters were calculated, for the computed and measured dose distributions, and tested for statistically significant differences.Results: Sensitometric curves showed a different behavior above dose of 5 Gy for EBT2 and EBT3 films; with the use of inhouse marker-dye correction method, the authors obtained values of 2.5% for flatness, 1.5% of symmetry, and a field width of 4.8 cm for a 5 × 5 cm{sup 2} reference field. Compared with TLD and selecting a 5% dose tolerance, the percentage of points with ICRU index below 1 was 100% for EBT2 and 83% for EBT3. Patients analysis revealed statistically significant differences (p < 0.05) between EBT2 and EBT3 in the percentage of points with gamma values <1 (p= 0.009 and p= 0.016); the percent difference as

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

A case-matched study of stereotactic radiosurgery for patients with brain metastases: comparing treatment results for those with versus without neurological symptoms.

PubMed

Koiso, Takao; Yamamoto, Masaaki; Kawabe, Takuya; Watanabe, Shinya; Sato, Yasunori; Higuchi, Yoshinori; Yamamoto, Tetsuya; Matsumura, Akira; Kasuya, Hidetoshi; Barfod, Bierta E

2016-12-01

We aimed to reappraise whether post-stereotactic radiosurgery (SRS) results for brain metastases differ between patients with and without neurological symptoms. This was an institutional review board-approved, retrospective cohort study using our prospectively accumulated database including 2825 consecutive BM patients undergoing gamma knife SRS alone during the 15-year period since July 1998. The 2825 patients were divided into two groups; neurologically asymptomatic [group A, 1374 patients (48.6 %)] and neurologically symptomatic [group B, 1451 (51.4 %)]. Because there was considerable bias in pre-SRS clinical factors between groups A and B, a case-matched study was conducted. Ultimately, 1644 patients (822 in each group) were selected. The standard Kaplan-Meier method was used to determine post-SRS survival. Competing risk analysis was applied to estimate cumulative incidences of neurological death, neurological deterioration, local recurrence, re-SRS for new lesions and SRS-induced complications. Post-SRS median survival times (MSTs) did not differ between the two groups; 7.8 months in group A versus 7.4 months in group B patients (HR 1.064, 95 % CI 0.963-1.177, p = 0.22). However, cumulative incidences of neurological death (HR 1.637, 95 % CI 1.174-2.281, p = 0.0036) and neurological deterioration (HR 1.425, 95 % CI 1.073-1.894, p = 0.014) were significantly lower in the group A than in the group B patients. Neurologically asymptomatic patients undergoing SRS for BM had better results than symptomatic patients in terms of both maintenance of good neurological state and prolonged neurological survival. Thus, we conclude that screening computed tomography/magnetic resonance imaging is highly beneficial for managing cancer patients.

Differences in Clinical Results After LINAC-Based Single-Dose Radiosurgery Versus Fractionated Stereotactic Radiotherapy for Patients With Vestibular Schwannomas

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

Combs, Stephanie E., E-mail: Stephanie.Combs@med.uni-heidelberg.d; Welzel, Thomas; Schulz-Ertner, Daniela

2010-01-15

Purpose: To evaluate the outcomes of patients with vestibular schwannoma (VS) treated with fractionated stereotactic radiotherapy (FSRT) vs. those treated with stereotactic radiosurgery (SRS). Methods and Materials: This study is based on an analysis of 200 patients with 202 VSs treated with FSRT (n = 172) or SRS (n = 30). Patients with tumor progression and/or progression of clinical symptoms were selected for treatment. In 165 out of 202 VSs (82%), RT was performed as the primary treatment for VS, and for 37 VSs (18%), RT was conducted for tumor progression after neurosurgical intervention. For patients receiving FSRT, a medianmore » total dose of 57.6 Gy was prescribed, with a median fractionation of 5 x 1.8 Gy per week. For patients who underwent SRS, a median single dose of 13 Gy was prescribed to the 80% isodose. Results: FSRT and SRS were well tolerated. Median follow-up time was 75 months. Local control was not statistically different for both groups. The probability of maintaining the pretreatment hearing level after SRS with doses of <=13 Gy was comparable to that of FSRT. The radiation dose for the SRS group (<=13 Gy vs. >13 Gy) significantly influenced hearing preservation rates (p = 0.03). In the group of patients treated with SRS doses of <=13 Gy, cranial nerve toxicity was comparable to that of the FSRT group. Conclusions: FSRT and SRS are both safe and effective alternatives for the treatment of VS. Local control rates are comparable in both groups. SRS with doses of <=13 Gy is a safe alternative to FSRT. While FSRT can be applied safely for the treatment of VSs of all sizes, SRS should be reserved for smaller lesions.« less

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

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

Juh, R; Suh, T; Kim, Y

2014-06-01

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

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

Factors Determining the Clinical Complications of Radiosurgery for AVM.

PubMed

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

2013-11-01

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

Association Between Radiation Necrosis and Tumor Biology After Stereotactic Radiosurgery for Brain Metastasis

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

Miller, Jacob A.; Bennett, Elizabeth E.; Xiao, Roy

Background: The primary dose-limiting toxicity of stereotactic radiosurgery (SRS) is radiation necrosis (RN), which occurs after approximately 5% to 10% of treatments. This adverse event may worsen neurologic deficits, increase the frequency and cost of imaging, and necessitate prolonged treatment with steroids or antiangiogenic agents. Previous investigations have primarily identified lesion size and dosimetric constraints as risk factors for RN in small populations. We hypothesized that disease histology, receptor status, and mutational status are associated with RN. Methods and Materials: All patients presenting with brain metastasis between 1997 and 2015 who underwent SRS and subsequent radiographic follow-up at a singlemore » tertiary-care institution were eligible for inclusion. The primary outcome was the cumulative incidence of radiographic RN. Multivariate competing risks regression was used to identify biological risk factors for RN. Results: 1939 patients (5747 lesions) were eligible for inclusion; 285 patients (15%) experienced radiographic RN after the treatment of 427 (7%) lesions. After SRS, the median time to RN was 7.6 months. After multivariate analysis, graded prognostic assessment, renal pathology, lesion diameter, and the heterogeneity index remained independently predictive of RN in the pooled cohort. In subset analyses of individual pathologies, HER2-amplified status (hazard ratio [HR] 2.05, P=.02), BRAF V600+ mutational status (HR 0.33, P=.04), lung adenocarcinoma histology (HR 1.89, P=.04), and ALK rearrangement (HR 6.36, P<.01) were also associated with RN. Conclusions: In the present investigation constituting the largest series of RN, several novel risk factors were identified, including renal histology, lung adenocarcinoma histology, HER2 amplification, and ALK/BRAF mutational status. These risk factors may be used to guide clinical trial design incorporating biological risk stratification or dose escalation. Future studies

Angiotensin receptor blockade: a novel approach for symptomatic radiation necrosis after stereotactic radiosurgery

PubMed Central

Okwan-Duodu, Derick; Switchenko, Jeffrey M.; Press, Robert H.; Jhaveri, Jaymin; Buchwald, Zachary S.; Zhong, Jim; Chapman, Bhavana V.; Bindra, Ranjit S.; Contessa, Joseph N.; Park, Henry S.; Yu, James B.; Decker, Roy H.; Olson, Jeffrey J.; Oyesiku, Nelson M.; Abrams, Ross A.; Shu, Hui-Kuo G.; Curran, Walter J.; Crocker, Ian R.

2018-01-01

Preclinical evidence suggests angiotensin blockade therapy (ABT) decreases late radiation toxicities. This study aims to investigate the association between ABT and symptomatic radiation necrosis (SRN) following stereotactic radiosurgery (SRS). Resected brain metastases (rBM) and arteriovenous malformation (AVM) patients treated with SRS from 2002 to 2015 were identified. Patients in the ABT cohort were on therapy during SRS and at 1-month follow up. Kaplan Meier method and cumulative incidence model were used to analyze overall survival (OS) and intracranial outcomes. 228 consecutive patients were treated with SRS: 111 with rBM and 117 with AVM. Overall, 51 (22.4%) patients were in the ABT group: 32 (28.8%) in the rBM and 19 (16.2%) in AVM cohorts. Baseline characteristics were similar, except for higher Graded Prognostic Analysis (3–4) in the rBM (ABT: 25.0% vs. non-ABT: 49.0%, p = 0.033) and median age in the AVM (ABT: 51.4 vs. non-ABT: 35.4, p < 0.001) cohorts. In both populations, OS and intracranial efficacy (rBM—local control; AVM—obliteration rates) were statistically similar between the cohorts. ABT was associated with lower 1-year SRN rates in both populations: rBM, 3.1 versus 25.3% (p = 0.003); AVM, 6.7 vs. 14.6% (p = 0.063). On multivariate analysis, ABT was a significant predictive factor for rBM (HR: 0.17; 95% CI 0.03–0.88, p = 0.035), but did not reach statistical significance for AVM (HR: 0.36; 95% CI 0.09–1.52, p = 0.165). ABT use appears to be associated with a reduced risk of SRN following SRS, without detriment to OS or intracranial efficacy. A prospective trial to validate these findings is warranted. PMID:29124649

Angiotensin receptor blockade: a novel approach for symptomatic radiation necrosis after stereotactic radiosurgery.

PubMed

Chowdhary, Mudit; Okwan-Duodu, Derick; Switchenko, Jeffrey M; Press, Robert H; Jhaveri, Jaymin; Buchwald, Zachary S; Zhong, Jim; Chapman, Bhavana V; Bindra, Ranjit S; Contessa, Joseph N; Park, Henry S; Yu, James B; Decker, Roy H; Olson, Jeffrey J; Oyesiku, Nelson M; Abrams, Ross A; Shu, Hui-Kuo G; Curran, Walter J; Crocker, Ian R; Patel, Kirtesh R

2018-01-01

Preclinical evidence suggests angiotensin blockade therapy (ABT) decreases late radiation toxicities. This study aims to investigate the association between ABT and symptomatic radiation necrosis (SRN) following stereotactic radiosurgery (SRS). Resected brain metastases (rBM) and arteriovenous malformation (AVM) patients treated with SRS from 2002 to 2015 were identified. Patients in the ABT cohort were on therapy during SRS and at 1-month follow up. Kaplan Meier method and cumulative incidence model were used to analyze overall survival (OS) and intracranial outcomes. 228 consecutive patients were treated with SRS: 111 with rBM and 117 with AVM. Overall, 51 (22.4%) patients were in the ABT group: 32 (28.8%) in the rBM and 19 (16.2%) in AVM cohorts. Baseline characteristics were similar, except for higher Graded Prognostic Analysis (3-4) in the rBM (ABT: 25.0% vs. non-ABT: 49.0%, p = 0.033) and median age in the AVM (ABT: 51.4 vs. non-ABT: 35.4, p < 0.001) cohorts. In both populations, OS and intracranial efficacy (rBM-local control; AVM-obliteration rates) were statistically similar between the cohorts. ABT was associated with lower 1-year SRN rates in both populations: rBM, 3.1 versus 25.3% (p = 0.003); AVM, 6.7 vs. 14.6% (p = 0.063). On multivariate analysis, ABT was a significant predictive factor for rBM (HR: 0.17; 95% CI 0.03-0.88, p = 0.035), but did not reach statistical significance for AVM (HR: 0.36; 95% CI 0.09-1.52, p = 0.165). ABT use appears to be associated with a reduced risk of SRN following SRS, without detriment to OS or intracranial efficacy. A prospective trial to validate these findings is warranted.

Dosimetry of cone-defined stereotactic radiosurgery fields with a commercial synthetic diamond detector.

PubMed

Morales, Johnny E; Crowe, Scott B; Hill, Robin; Freeman, Nigel; Trapp, J V

2014-11-01

Small field x-ray beam dosimetry is difficult due to lack of lateral electronic equilibrium, source occlusion, high dose gradients, and detector volume averaging. Currently, there is no single definitive detector recommended for small field dosimetry. The objective of this work was to evaluate the performance of a new commercial synthetic diamond detector, namely, the PTW 60019 microDiamond, for the dosimetry of small x-ray fields as used in stereotactic radiosurgery (SRS). Small field sizes were defined by BrainLAB circular cones (4-30 mm diameter) on a Novalis Trilogy linear accelerator and using the 6 MV SRS x-ray beam mode for all measurements. Percentage depth doses (PDDs) were measured and compared to an IBA SFD and a PTW 60012 E diode. Cross profiles were measured and compared to an IBA SFD diode. Field factors, ΩQclin,Qmsr (fclin,fmsr) , were calculated by Monte Carlo methods using BEAMnrc and correction factors, kQclin,Qmsr (fclin,fmsr) , were derived for the PTW 60019 microDiamond detector. For the small fields of 4-30 mm diameter, there were dose differences in the PDDs of up to 1.5% when compared to an IBA SFD and PTW 60012 E diode detector. For the cross profile measurements the penumbra values varied, depending upon the orientation of the detector. The field factors, ΩQclin,Qmsr (fclin,fmsr) , were calculated for these field diameters at a depth of 1.4 cm in water and they were within 2.7% of published values for a similar linear accelerator. The corrections factors, kQclin,Qmsr (fclin,fmsr) , were derived for the PTW 60019 microDiamond detector. The authors conclude that the new PTW 60019 microDiamond detector is generally suitable for relative dosimetry in small 6 MV SRS beams for a Novalis Trilogy linear equipped with circular cones.

Hematological Toxicity After Robotic Stereotactic Body Radiosurgery for Treatment of Metastatic Gynecologic Malignancies

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

Kunos, Charles A., E-mail: charles.kunos@UHhospitals.org; Debernardo, Robert; Radivoyevitch, Tomas

Purpose: To evaluate hematological toxicity after robotic stereotactic body radiosurgery (SBRT) for treatment of women with metastatic abdominopelvic gynecologic malignancies. Methods and Materials: A total of 61 women with stage IV gynecologic malignancies treated with abdominopelvic SBRT were analyzed after ablative radiation (2400 cGy/3 divided consecutive daily doses) delivered by a robotic-armed Cyberknife SBRT system. Abdominopelvic bone marrow was identified using computed tomography-guided contouring. Fatigue and hematologic toxicities were graded by retrospective assignment of common toxicity criteria for adverse events (version 4.0). Bone marrow volume receiving 1000 cGy (V10) was tested for association with post-therapy (median 32 days [25%-75% quartile,more » 28-45 days]) white- or red-cell counts, hemoglobin levels, and platelet counts as marrow toxicity surrogates. Results: In all, 61 women undergoing abdominopelvic SBRT had a median bone marrow V10 of 2% (25%-75% quartile: 0%-8%). Fifty-seven (93%) of 61 women had received at least 1 pre-SBRT marrow-taxing chemotherapy regimen for metastatic disease. Bone marrow V10 did not associate with hematological adverse events. In all, 15 grade 2 (25%) and 2 grade 3 (3%) fatigue symptoms were self-reported among the 61 women within the first 10 days post-therapy, with fatigue resolved spontaneously in all 17 women by 30 days post-therapy. Neutropenia was not observed. Three (5%) women had a grade 1 drop in hemoglobin level to <10.0 g/dL. Single grade 1, 2, and 3 thrombocytopenias were documented in 3 women. Conclusions: Abdominopelvic SBRT provided ablative radiation dose to cancer targets without increased bone marrow toxicity. Abdominopelvic SBRT for metastatic gynecologic malignancies warrants further study.« less

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.

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

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.

Accuracy of marketing claims by providers of stereotactic radiation therapy.

PubMed

Narang, Amol K; Lam, Edwin; Makary, Martin A; Deweese, Theodore L; Pawlik, Timothy M; Pronovost, Peter J; Herman, Joseph M

2013-01-01

Direct-to-consumer advertising by industry has been criticized for encouraging overuse of unproven therapies, but advertising by health care providers has not been as carefully scrutinized. Stereotactic radiation therapy is an emerging technology that has sparked controversy regarding the marketing campaigns of some manufacturers. Given that this technology is also being heavily advertised on the Web sites of health care providers, the accuracy of providers' marketing claims should be rigorously evaluated. We reviewed the Web sites of all U.S. hospitals and private practices that provide stereotactic radiation using two leading brands of stereotactic radiosurgery technology. Centers were identified by using data from the manufacturers. Centers without Web sites were excluded. The final study population consisted of 212 centers with online advertisements for stereotactic radiation. Web sites were evaluated for advertisements that were inconsistent with advertising guidelines provided by the American Medical Association. Most centers (76%) had individual pages dedicated to the marketing of their brand of stereotactic technology that frequently contained manufacturer-authored images (50%) or text (55%). Advertising for the treatment of tumors that have not been endorsed by professional societies was present on 66% of Web sites. Centers commonly claimed improved survival (22%), disease control (20%), quality of life (17%), and toxicity (43%) with stereotactic radiation. Although 40% of Web sites championed the center's regional expertise in delivering stereotactic treatments, only 15% of Web sites provided data to support their claims. Provider advertisements for stereotactic radiation were prominent and aggressive. Further investigation of provider advertising, its effects on quality of care, and potential oversight mechanisms is needed.

Automatic metastatic brain tumor segmentation for stereotactic radiosurgery applications.

PubMed

Liu, Yan; Stojadinovic, Strahinja; Hrycushko, Brian; Wardak, Zabi; Lu, Weiguo; Yan, Yulong; Jiang, Steve B; Timmerman, Robert; Abdulrahman, Ramzi; Nedzi, Lucien; Gu, Xuejun

2016-12-21

The objective of this study is to develop an automatic segmentation strategy for efficient and accurate metastatic brain tumor delineation on contrast-enhanced T1-weighted (T1c) magnetic resonance images (MRI) for stereotactic radiosurgery (SRS) applications. The proposed four-step automatic brain metastases segmentation strategy is comprised of pre-processing, initial contouring, contour evolution, and contour triage. First, T1c brain images are preprocessed to remove the skull. Second, an initial tumor contour is created using a multi-scaled adaptive threshold-based bounding box and a super-voxel clustering technique. Third, the initial contours are evolved to the tumor boundary using a regional active contour technique. Fourth, all detected false-positive contours are removed with geometric characterization. The segmentation process was validated on a realistic virtual phantom containing Gaussian or Rician noise. For each type of noise distribution, five different noise levels were tested. Twenty-one cases from the multimodal brain tumor image segmentation (BRATS) challenge dataset and fifteen clinical metastases cases were also included in validation. Segmentation performance was quantified by the Dice coefficient (DC), normalized mutual information (NMI), structural similarity (SSIM), Hausdorff distance (HD), mean value of surface-to-surface distance (MSSD) and standard deviation of surface-to-surface distance (SDSSD). In the numerical phantom study, the evaluation yielded a DC of 0.98  ±  0.01, an NMI of 0.97  ±  0.01, an SSIM of 0.999  ±  0.001, an HD of 2.2  ±  0.8 mm, an MSSD of 0.1  ±  0.1 mm, and an SDSSD of 0.3  ±  0.1 mm. The validation on the BRATS data resulted in a DC of 0.89  ±  0.08, which outperform the BRATS challenge algorithms. Evaluation on clinical datasets gave a DC of 0.86  ±  0.09, an NMI of 0.80  ±  0.11, an SSIM of 0.999  ±  0.001, an HD of 8

Automatic metastatic brain tumor segmentation for stereotactic radiosurgery applications

NASA Astrophysics Data System (ADS)

Liu, Yan; Stojadinovic, Strahinja; Hrycushko, Brian; Wardak, Zabi; Lu, Weiguo; Yan, Yulong; Jiang, Steve B.; Timmerman, Robert; Abdulrahman, Ramzi; Nedzi, Lucien; Gu, Xuejun

2016-12-01

The objective of this study is to develop an automatic segmentation strategy for efficient and accurate metastatic brain tumor delineation on contrast-enhanced T1-weighted (T1c) magnetic resonance images (MRI) for stereotactic radiosurgery (SRS) applications. The proposed four-step automatic brain metastases segmentation strategy is comprised of pre-processing, initial contouring, contour evolution, and contour triage. First, T1c brain images are preprocessed to remove the skull. Second, an initial tumor contour is created using a multi-scaled adaptive threshold-based bounding box and a super-voxel clustering technique. Third, the initial contours are evolved to the tumor boundary using a regional active contour technique. Fourth, all detected false-positive contours are removed with geometric characterization. The segmentation process was validated on a realistic virtual phantom containing Gaussian or Rician noise. For each type of noise distribution, five different noise levels were tested. Twenty-one cases from the multimodal brain tumor image segmentation (BRATS) challenge dataset and fifteen clinical metastases cases were also included in validation. Segmentation performance was quantified by the Dice coefficient (DC), normalized mutual information (NMI), structural similarity (SSIM), Hausdorff distance (HD), mean value of surface-to-surface distance (MSSD) and standard deviation of surface-to-surface distance (SDSSD). In the numerical phantom study, the evaluation yielded a DC of 0.98  ±  0.01, an NMI of 0.97  ±  0.01, an SSIM of 0.999  ±  0.001, an HD of 2.2  ±  0.8 mm, an MSSD of 0.1  ±  0.1 mm, and an SDSSD of 0.3  ±  0.1 mm. The validation on the BRATS data resulted in a DC of 0.89  ±  0.08, which outperform the BRATS challenge algorithms. Evaluation on clinical datasets gave a DC of 0.86  ±  0.09, an NMI of 0.80  ±  0.11, an SSIM of 0.999  ±  0.001, an HD of 8

Stereotactic radiosurgery with the linear accelerator: treatment of arteriovenous malformations.

PubMed

Betti, O O; Munari, C; Rosler, R

1989-03-01

An original stereotactic radiosurgical approach coupling a) Talairach's stereotactic methodology, b) a specially devised mechanical system, and c) a linear accelerator is detailed. The authors present their preliminary results on 66 patients with nonsurgical intracranial arteriovenous malformations. The doses delivered for treatment varied from 20 to 70 Gy. Doses of no more than 40 Gy were used in 80% of patients. An angiographic study was performed when the computed tomographic scan controls showed relevant modifications of the lesion volume. Total obliteration was obtained in 27 of the 41 patients (65.8%) who were followed up for at least 24 months. The percentage of the cured patients is significantly higher when a) the entire malformation is included in the 75% isodose (96%) and b) the maximum diameter of the lesion is less than 12 mm (81%). Two patients died of rebleeding at 18 and 29 months after treatment.

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.

Cost-effectiveness of stereotactic radiosurgery with and without whole-brain radiotherapy for the treatment of newly diagnosed brain metastases.

PubMed

Hall, Matthew D; McGee, James L; McGee, Mackenzie C; Hall, Kevin A; Neils, David M; Klopfenstein, Jeffrey D; Elwood, Patrick W

2014-12-01

Stereotactic radiosurgery (SRS) alone is increasingly used in patients with newly diagnosed brain metastases. Stereotactic radiosurgery used together with whole-brain radiotherapy (WBRT) reduces intracranial failure rates, but this combination also causes greater neurocognitive toxicity and does not improve survival. Critics of SRS alone contend that deferring WBRT results in an increased need for salvage therapy and in higher costs. The authors compared the cost-effectiveness of treatment with SRS alone, SRS and WBRT (SRS+WBRT), and surgery followed by SRS (S+SRS) at the authors' institution. The authors retrospectively reviewed the medical records of 289 patients in whom brain metastases were newly diagnosed and who were treated between May 2001 and December 2007. Overall survival curves were plotted using the Kaplan-Meier method. Multivariate proportional hazards analysis (MVA) was used to identify factors associated with overall survival. Survival data were complete for 96.2% of patients, and comprehensive data on the resource use for imaging, hospitalizations, and salvage therapies were available from the medical records. Treatment costs included the cost of initial and all salvage therapies for brain metastases, hospitalizations, management of complications, and imaging. They were computed on the basis of the 2007 Medicare fee schedule from a payer perspective. Average treatment cost and average cost per month of median survival were compared. Sensitivity analysis was performed to examine the impact of variations in key cost variables. No significant differences in overall survival were observed among patients treated with SRS alone, SRS+WBRT, or S+SRS with respective median survival of 9.8, 7.4, and 10.6 months. The MVA detected a significant association of overall survival with female sex, Karnofsky Performance Scale (KPS) score, primary tumor control, absence of extracranial metastases, and number of brain metastases. Salvage therapy was required in 43% of

Efficacy of Stereotactic Radiosurgery in Patients with Multiple Metastases: Importance of Volume Rather Than Number of Lesions.

PubMed

Dahshan, Basem A; Mattes, Malcolm D; Bhatia, Sanjay; Palek, Mary Susan; Cifarelli, Christopher P; Hack, Joshua D; Vargo, John A

2017-12-19

The role of stereotactic radiosurgery (SRS) in the treatment of multiple brain metastases is controversial. While whole brain radiation therapy (WBRT) has historically been the mainstay of treatment, its value is increasingly being questioned as emerging data supports that SRS alone can provide comparable therapeutic outcomes for limited (one to three) intracranial metastases with fewer adverse effects, including neurocognitive decline. Multiple recent studies have also demonstrated that patients with multiple (> 3) intracranial metastases with a low overall tumor volume have a favorable therapeutic response to SRS, with no significant difference compared to patients with limited metastases. Herein, we present a patient with previously controlled breast cancer who presented with multiple recurrences of intracranial metastases but low total intracranial tumor volume each time. This patient underwent SRS alone for a total of 40 metastatic lesions over three separate procedures with good local control and without any significant cognitive toxicity. The patient eventually opted for enrollment in the NRG-CC001 clinical trial after multiple cranial recurrences. She received conventional WBRT with six months of memantine and developed significant neurocognitive side effects. This case highlights the growing body of literature supporting the role of SRS alone in the management of multiple brain metastases and the importance of maximizing neurocognition as advances in systemic therapies prolong survival in Stage IV cancer.

Efficacy of Stereotactic Radiosurgery in Patients with Multiple Metastases: Importance of Volume Rather Than Number of Lesions

PubMed Central

Mattes, Malcolm D; Bhatia, Sanjay; Palek, Mary Susan; Cifarelli, Christopher P; Hack, Joshua D; Vargo, John A

2017-01-01

The role of stereotactic radiosurgery (SRS) in the treatment of multiple brain metastases is controversial. While whole brain radiation therapy (WBRT) has historically been the mainstay of treatment, its value is increasingly being questioned as emerging data supports that SRS alone can provide comparable therapeutic outcomes for limited (one to three) intracranial metastases with fewer adverse effects, including neurocognitive decline. Multiple recent studies have also demonstrated that patients with multiple (> 3) intracranial metastases with a low overall tumor volume have a favorable therapeutic response to SRS, with no significant difference compared to patients with limited metastases. Herein, we present a patient with previously controlled breast cancer who presented with multiple recurrences of intracranial metastases but low total intracranial tumor volume each time. This patient underwent SRS alone for a total of 40 metastatic lesions over three separate procedures with good local control and without any significant cognitive toxicity. The patient eventually opted for enrollment in the NRG-CC001 clinical trial after multiple cranial recurrences. She received conventional WBRT with six months of memantine and developed significant neurocognitive side effects. This case highlights the growing body of literature supporting the role of SRS alone in the management of multiple brain metastases and the importance of maximizing neurocognition as advances in systemic therapies prolong survival in Stage IV cancer. PMID:29492355

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

PubMed

Amichetti, Maurizio; Amelio, Dante; Minniti, Giuseppe

2012-12-14

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

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

PubMed Central

2012-01-01

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

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.

Survival was Significantly Better with Surgical/Medical/Radiation Co-interventions in a Single-Institution Practice Audit of Frameless Stereotactic Radiosurgery.

PubMed

Taggar, Amandeep; MacKenzie, Joanna; Li, Haocheng; Lau, Harold; Lim, Gerald; Nordal, Robert; Hudson, Alana; Khan, Rao; Spencer, David; Voroney, Jon-Paul

2016-05-17

To audit outcomes after introducing frameless stereotactic radiosurgery (SRS) for brain metastases, including co-interventions: neurosurgery, systemic therapy, and whole brain radiotherapy (WBRT). We report median overall survival (MS), local failure, and distant brain failure. We hypothesized patients treated with SRS would have clinically meaningful improved MS compared with historic institutional values. We further hypothesized that patients treated with co-interventions would have clinically meaningful improved MS compared with patients treated with SRS alone. One hundred twenty patients (N = 120) with limited intracranial disease underwent 130 frameless SRS sessions from April 2010 to May 2013. Median follow-up was 11 months. MS was measured from brain metastases diagnosis, local failure, and distant brain failure from the time of first SRS. Practice pattern during the first year of the study favored upfront WBRT (79%) over SRS (21%) while upfront SRS (45%) was almost as common as upfront WBRT (55%) in the last year of the study. MS was 18 months; 37% received SRS alone as initial radiotherapy (MS 12 months); 63% received WBRT prior to SRS (MS 19 months); 50% received systemic therapy post-SRS (MS 21 months); and 26% had tumor resection then SRS to the surgical cavity (MS 42 months). Local failure occurred in 10% of lesions and radio-necrosis occurred in 4%. Differences in distant brain failure among patients treated with upfront SRS (40% rate), WBRT followed by SRS (33% rate) or systemic therapy post-SRS (37% rate) were not statistically significant. Frameless SRS effectively treats surgical cavities, persistent tumors post-WBRT, and can be used as an upfront treatment of brain metastases. Surgery, systemic therapy, and WBRT are associated with longer MS. Patients can live for years while receiving multiple therapies. Systemic therapy for patients with brain metastases is increasingly common, palliative care occurs earlier and improves

Single-Fraction Proton Beam Stereotactic Radiosurgery for Cerebral Arteriovenous Malformations

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

Hattangadi-Gluth, Jona A.; Chapman, Paul H.; Kim, Daniel

2014-06-01

Purpose/Objective(s): To evaluate the obliteration rate and potential adverse effects of single-fraction proton beam stereotactic radiosurgery (PSRS) in patients with cerebral arteriovenous malformations (AVMs). Methods and Materials: From 1991 to 2010, 248 consecutive patients with 254 cerebral AVMs received single-fraction PSRS at our institution. The median AVM nidus volume was 3.5 cc (range, 0.1-28.1 cc), 23% of AVMs were in critical/deep locations (basal ganglia, thalamus, or brainstem), and the most common prescription dose was 15 Gy(relative biological effectiveness [RBE]). Univariable and multivariable analyses were performed to assess factors associated with obliteration and hemorrhage. Results: At a median follow-up time of 35 months (range, 6-198 months),more » 64.6% of AVMs were obliterated. The median time to total obliteration was 31 months (range, 6-127 months), and the 5-year and 10-year cumulative incidence of total obliteration was 70% and 91%, respectively. On univariable analysis, smaller target volume (hazard ratio [HR] 0.78, 95% confidence interval [CI] 0.86-0.93, P<.0001), smaller treatment volume (HR 0.93, 95% CI 0.90-0.96, P<.0001), higher prescription dose (HR 1.16, 95% CI 1.07-1.26, P=.001), and higher maximum dose (HR 1.14, 95% CI 1.05-1.23, P=.002) were associated with total obliteration. Deep/critical location was also associated with decreased likelihood of obliteration (HR 0.68, 95% CI 0.47-0.98, P=.04). On multivariable analysis, critical location (adjusted HR [AHR] 0.42, 95% CI 0.27-0.65, P<.001) and smaller target volume (AHR 0.81, 95% CI 0.68-0.97, P=.02) remained associated with total obliteration. Posttreatment hemorrhage occurred in 13 cases (5-year cumulative incidence of 7%), all among patients with less than total obliteration, and 3 of these events were fatal. The most common complication was seizure, controlled with medications, both acutely (8%) and in the long term (9.1%). Conclusions: The current series is the

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.

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.

SU-E-T-128: Applying Failure Modes and Effects Analysis to a Risk-Based Quality Management for Stereotactic Radiosurgery in Brazil

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

Teixeira, F; Universidade do Estado do Rio de Janeiro, Rio De Janeiro, RJ; Almeida, C de

2015-06-15

Purpose: The goal of the present work was to evaluate the process maps for stereotactic radiosurgery (SRS) treatment at three radiotherapy centers in Brazil and apply the FMEA technique to evaluate similarities and differences, if any, of the hazards and risks associated with these processes. Methods: A team, consisting of professionals from different disciplines and involved in the SRS treatment, was formed at each center. Each team was responsible for the development of the process map, and performance of FMEA and FTA. A facilitator knowledgeable in these techniques led the work at each center. The TG100 recommended scales were usedmore » for the evaluation of hazard and severity for each step for the major process “treatment planning”. Results: Hazard index given by the Risk Priority Number (RPN) is found to range from 4–270 for various processes and the severity (S) index is found to range from 1–10. The RPN values > 100 and severity value ≥ 7 were chosen to flag safety improvement interventions. Number of steps with RPN ≥100 were found to be 6, 59 and 45 for the three centers. The corresponding values for S ≥ 7 are 24, 21 and 25 respectively. The range of RPN and S values for each center belong to different process steps and failure modes. Conclusion: These results show that interventions to improve safety is different for each center and it is associated with the skill level of the professional team as well as the technology used to provide radiosurgery treatment. The present study will very likely be a model for implementation of risk-based prospective quality management program for SRS treatment in Brazil where currently there are 28 radiotherapy centers performing SRS. A complete FMEA for SRS for these three radiotherapy centers is currently under development.« less

TH-A-BRC-00: New Task Groups for External Beam QA: An Overview

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

NONE

2016-06-15

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

TH-A-BRC-03: AAPM TG218: Measurement Methods and Tolerance Levels for Patient-Specific IMRT Verification QA

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

Miften, M.

2016-06-15

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

Proton beam radiosurgery for vestibular schwannoma: tumor control and cranial nerve toxicity.

PubMed

Weber, Damien C; Chan, Annie W; Bussiere, Marc R; Harsh, Griffith R; Ancukiewicz, Marek; Barker, Fred G; Thornton, Allan T; Martuza, Robert L; Nadol, Joseph B; Chapman, Paul H; Loeffler, Jay S

2003-09-01

We sought to determine the tumor control rate and cranial nerve function outcomes in patients with vestibular schwannomas who were treated with proton beam stereotactic radiosurgery. Between November 1992 and August 2000, 88 patients with vestibular schwannomas were treated at the Harvard Cyclotron Laboratory with proton beam stereotactic radiosurgery in which two to four convergent fixed beams of 160-MeV protons were applied. The median transverse diameter was 16 mm (range, 2.5-35 mm), and the median tumor volume was 1.4 cm(3) (range, 0.1-15.9 cm(3)). Surgical resection had been performed previously in 15 patients (17%). Facial nerve function (House-Brackmann Grade 1) and trigeminal nerve function were normal in 79 patients (89.8%). Eight patients (9%) had good or excellent hearing (Gardner-Robertson [GR] Grade 1), and 13 patients (15%) had serviceable hearing (GR Grade 2). A median dose of 12 cobalt Gray equivalents (range, 10-18 cobalt Gray equivalents) was prescribed to the 70 to 108% isodose lines (median, 70%). The median follow-up period was 38.7 months (range, 12-102.6 mo). The actuarial 2- and 5-year tumor control rates were 95.3% (95% confidence interval [CI], 90.9-99.9%) and 93.6% (95% CI, 88.3-99.3%). Salvage radiosurgery was performed in one patient 32.5 months after treatment, and a craniotomy was required 19.1 months after treatment in another patient with hemorrhage in the vicinity of a stable tumor. Three patients (3.4%) underwent shunting for hydrocephalus, and a subsequent partial resection was performed in one of these patients. The actuarial 5-year cumulative radiological reduction rate was 94.7% (95% CI, 81.2-98.3%). Of the 21 patients (24%) with functional hearing (GR Grade 1 or 2), 7 (33.3%) retained serviceable hearing ability (GR Grade 2). Actuarial 5-year normal facial and trigeminal nerve function preservation rates were 91.1% (95% CI, 85-97.6%) and 89.4% (95% CI, 82-96.7%). Univariate analysis revealed that prescribed dose (P = 0

Accuracy of Marketing Claims by Providers of Stereotactic Radiation Therapy

PubMed Central

Narang, Amol K.; Lam, Edwin; Makary, Martin A.; DeWeese, Theodore L.; Pawlik, Timothy M.; Pronovost, Peter J.; Herman, Joseph M.

2013-01-01

Purpose: Direct-to-consumer advertising by industry has been criticized for encouraging overuse of unproven therapies, but advertising by health care providers has not been as carefully scrutinized. Stereotactic radiation therapy is an emerging technology that has sparked controversy regarding the marketing campaigns of some manufacturers. Given that this technology is also being heavily advertised on the Web sites of health care providers, the accuracy of providers' marketing claims should be rigorously evaluated. Methods: We reviewed the Web sites of all US hospitals and private practices that provide stereotactic radiation using two leading brands of stereotactic radiosurgery technology. Centers were identified by using data from the manufacturers. Centers without Web sites were excluded. The final study population consisted of 212 centers with online advertisements for stereotactic radiation. Web sites were evaluated for advertisements that were inconsistent with advertising guidelines provided by the American Medical Association. Results: Most centers (76%) had individual pages dedicated to the marketing of their brand of stereotactic technology that frequently contained manufacturer-authored images (50%) or text (55%). Advertising for the treatment of tumors that have not been endorsed by professional societies was present on 66% of Web sites. Centers commonly claimed improved survival (22%), disease control (20%), quality of life (17%), and toxicity (43%) with stereotactic radiation. Although 40% of Web sites championed the center's regional expertise in delivering stereotactic treatments, only 15% of Web sites provided data to support their claims. Conclusion: Provider advertisements for stereotactic radiation were prominent and aggressive. Further investigation of provider advertising, its effects on quality of care, and potential oversight mechanisms is needed. PMID:23633973

Evaluation of radiosurgery techniques–Cone-based linac radiosurgery vs tomotherapy-based radiosurgery

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

Yip, Ho Yin, E-mail: hoyinyip@yahoo.com.hk; Mui, Wing Lun A.; Lee, Joseph W.Y.

2013-07-01

Performances of radiosurgery of intracranial lesions between cone-based Linac system and Tomotherapy-based system were compared in terms of dosimetry and time. Twelve patients with single intracranial lesion treated with cone-based Linac radiosurgery system from 2005 to 2009 were replanned for Tomotherapy-based radiosurgery treatment. The conformity index, homogeneity index (HI), and gradient score index (GSI) of each case was calculated. The Wilcoxon matched-pair test was used to compare the 3 indices between both systems. The cases with regular target (n = 6) and those with irregular target (n = 6) were further analyzed separately. The estimated treatment time between both systemsmore » was also compared. Significant differences were found in HI (p = 0.05) and in GSI (p = 0.03) for the whole group. Cone-based radiosurgery was better in GSI whereas Tomotherapy-based radiosurgery was better in HI. Cone-based radiosurgery was better in conformity index (p = 0.03) and GSI (p = 0.03) for regular targets, whereas Tomotherapy-based radiosurgery system performed significantly better in HI (p = 0.03) for irregular targets. The estimated total treatment time for Tomotherapy-based radiosurgery ranged from 24 minutes to 35 minutes, including 15 minutes of pretreatment megavoltage computed tomography (MVCT) and image registration, whereas that for cone-based radiosurgery ranged from 15 minutes for 1 isocenter to 75 minutes for 5 isocenters. As a rule of thumb, Tomotherapy-based radiosurgery system should be the first-line treatment for irregular lesions because of better dose homogeneity and shorter treatment time. Cone-based Linac radiosurgery system should be the treatment of choice for regular targets because of the better dose conformity, rapid dose fall-off, and reasonable treatment time.« less

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.

10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Additional technical requirements for mobile remote afterloader units. 35.647 Section 35.647 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery...

10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Additional technical requirements for mobile remote afterloader units. 35.647 Section 35.647 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery...

10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Additional technical requirements for mobile remote afterloader units. 35.647 Section 35.647 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery...

10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Additional technical requirements for mobile remote afterloader units. 35.647 Section 35.647 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery...

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

Three or More Courses of Stereotactic Radiosurgery for Patients with Multiply Recurrent Brain Metastases.

PubMed

Kotecha, Rupesh; Damico, Nicholas; Miller, Jacob A; Suh, John H; Murphy, Erin S; Reddy, Chandana A; Barnett, Gene H; Vogelbaum, Michael A; Angelov, Lilyana; Mohammadi, Alireza M; Chao, Samuel T

2017-06-01

Although patients with brain metastasis are treated with primary stereotactic radiosurgery (SRS), the use of salvage therapies and their consequence remains understudied. To study the intracranial recurrence patterns and salvage therapies for patients who underwent multiple SRS courses. A retrospective review was performed of 59 patients with brain metastases who underwent ≥3 SRS courses for new lesions. Cox regression analyzed factors predictive for overall survival. The median age at diagnosis was 52 years. Over time, patients underwent a median of 3 courses of SRS (range: 3-8) to a total of 765 different brain metastases. The 6-month risk of distant intracranial recurrence after the first SRS treatment was 64% (95% confidence interval: 52%-77%). Overall survival was 40% (95% confidence interval: 28%-53%) at 24 months. Only 24 patients (41%) had a decline in their Karnofsky Performance Status ≤70 at last office visit. Quality of life was preserved among 77% of patients at 12 months, with 45% experiencing clinically significant improvement during clinical follow-up. Radiation necrosis developed in 10 patients (17%). On multivariate analysis, gender (males, Hazard Ratio [HR]: 2.0, P < .05), Karnofsky Performance Status ≤80 (HR 3.2, P < .001), extracranial metastases (HR: 3.6, P < .001), and a distant intracranial recurrence ≤3 months from initial to repeat SRS (HR: 3.8, P < .001) were associated with a poorer survival. In selected patients, performing ≥3 SRS courses controls intracranial disease. Patients may need salvage SRS for distant intracranial relapse, but focal retreatments are associated with modest toxicity, do not appear to negatively affect a patient's performance status, and help preserve quality of life. Copyright © 2017 by the Congress of Neurological Surgeons

Stereotactic radiosurgery for small brain metastases and implications regarding management with systemic therapy alone.

PubMed

Trifiletti, Daniel M; Hill, Colin; Cohen-Inbar, Or; Xu, Zhiyuan; Sheehan, Jason P

2017-09-01

While stereotactic radiosurgery (SRS) has been shown effective in the management of brain metastases, small brain metastases (≤10 mm) can pose unique challenges. Our aim was to investigate the efficacy of SRS in the treatment of small brain metastases, as well as elucidate clinically relevant factors impacting local failure (LF). We utilized a large, single-institution cohort to perform a retrospective analysis of patients with brain metastases up to 1 cm in maximal dimension. Clinical and radiosurgical parameters were investigated for an association with LF and compared using a competing risk model to calculate cumulative incidence functions, with death and whole brain radiotherapy serving as competing risks. 1596 small brain metastases treated with SRS among 424 patients were included. Among these tumors, 33 developed LF during the follow-up period (2.4% at 12 months following SRS). Competing risk analysis demonstrated that LF was dependent on tumor size (0.7% if ≤2 mm and 3.0% if 2-10 mm at 12 months, p = 0.016). Other factors associated with increasing risk of LF were the decreasing margin dose, increasing maximal tumor diameter, volume, and radioresistant tumors (each p < 0.01). 22 tumors (0.78%) developed radiographic radiation necrosis following SRS, and this incidence did not differ by tumor size (≤2 mm and 2-10 mm, p = 0.200). This large analysis confirms that SRS remains an effective modality in treatment of small brain metastases. In light of the excellent local control and relatively low risk of toxicity, patients with small brain metastases who otherwise have a reasonable expected survival should be considered for radiosurgical management.

Stereotactic Radiosurgery: Treatment of Brain Metastasis Without Interruption of Systemic Therapy

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

Shen, Colette J.; Kummerlowe, Megan N.; Redmond, Kristin J.

Purpose: To evaluate the prevalence, outcomes, and toxicities of concurrent delivery of systemic therapy with stereotactic radiosurgery (SRS) for treatment of brain metastases. Methods and Materials: We conducted a retrospective review of 193 patients treated at our institution with SRS without prior whole-brain radiation therapy (WBRT) for brain metastases between 2009 and 2014. Outcome metrics included administration of concurrent systemic therapy, myelosuppression, neurotoxicity, and survival. Results: One hundred ninety-three patients with a median age of 61 years underwent a total of 291 SRS treatments. Thirty-seven percent of SRS treatments were delivered concurrently with systemic therapy, of which 46% were with conventional myelosuppressivemore » chemotherapy, and 54% with targeted and immune therapy agents. Myelosuppression was minimal after treatment with both systemic therapy and SRS, with 14% grade 3-4 toxicity for lymphopenia and 4-9% for leukopenia, neutropenia, anemia, and thrombocytopenia. Neurotoxicity was also minimal after combined therapy, with no grade 4 and <5% grade 3 toxicity, 34% dexamethasone requirement, and 4% radiation necrosis, all similar to treatments with SRS alone. Median overall survival was similar after SRS alone (14.4 months) versus SRS with systemic therapy (12.9 months). In patients with a new diagnosis of primary cancer with brain metastasis, early treatment with concurrent systemic therapy and SRS correlated with improved survival versus SRS alone (41.6 vs 21.5 months, P<.05). Conclusions: Systemic therapy can be safely given concurrently with SRS for brain metastases: our results suggest minimal myelosuppression and neurotoxicity. Concurrent therapy is an attractive option for patients who have both intracranial and extracranial metastatic disease and may be particularly beneficial in patients with a new diagnosis of primary cancer with brain metastasis.« less

Multidisciplinary treatment of brain metastases derived from clear cell renal cancer incorporating stereotactic radiosurgery.

PubMed

Samlowski, Wolfram E; Majer, Martin; Boucher, Kenneth M; Shrieve, Annabelle F; Dechet, Christopher; Jensen, Randy L; Shrieve, Dennis C

2008-11-01

Brain metastases are a frequent complication in patients with metastatic clear cell renal cancer. Survival after whole-brain radiotherapy (WBRT) is disappointing. A retrospective analysis of multimodality treatment was performed in patients who had received linear accelerator (LINAC)-based stereotactic radiosurgery (SRS). Thirty-two patients underwent SRS-based treatment for 71 metastatic foci between 2000 and 2006. All patients had a Karnofsky performance status >or=70 and all 32 patients had extracranial metastatic disease (Radiation Therapy Oncology Group recursive partitioning analysis [RPA] Class 2). Survival was calculated from the time of diagnosis of brain metastases. The minimum potential follow-up was 1 year after SRS. Univariate and multivariate analysis of potential prognostic factors affecting survival was performed. Twenty-six patients required only 1 SRS treatment (84%) to achieve central nervous system (CNS) control, whereas 5 patients received 2 to 3 treatments (16%). The median survival of renal cancer patients from the diagnosis of brain metastases was 10.1 months (95% confidence interval, 6.4-14.8 months). One-year and 3-year survival rates were 43% and 16%, respectively. The addition of surgery or WBRT did not appear to prolong survival. Immunotherapy after control of brain metastases with SRS appeared to result in significantly improved survival. Survival was also found to be strongly influenced by prognostic stratification of metastatic disease using Motzer or modified risk criteria. The results of the current study demonstrated that SRS-based treatment of patients with up to 5 brain metastases from clear cell renal cancer is feasible and results in excellent CNS control. Survival beyond 3 years from the time of diagnosis of brain metastases was achievable in 16% of patients and was associated with the use of systemic immunotherapy with interleukin-2 and interferon but not antiangiogenic agents.

Stereotactic radiosurgery boost to the resection cavity for cerebral metastases: Report of overall survival, complications, and corticosteroid protocol

PubMed Central

Kellogg, Robert G.; Straus, David C.; Choi, Mehee; Chaudhry, Thymur A.; Diaz, Aidnag Z.; Muñoz, Lorenzo F.

2013-01-01

Background: This report focuses on the overall survival and complications associated with treatment of cerebral metastases with surgical resection followed by stereotactic radiosurgery (SRS). Management and complications of corticosteroid therapy are underreported in the literature but represent an important source of morbidity for patients. Methods: Fifty-nine consecutive patients underwent surgical resection of a cerebral metastasis followed by SRS to the cavity. Patient charts were reviewed retrospectively to ascertain overall survival, local control, surgical complications, SRS complications, and corticosteroid complications. Results: Our mean follow-up was 14.4 months (median 12.0 months, range 0.9-62.9 months). Median overall survival in this series was 15.25 months and local control was 98.3%. There was a statistically significant survival benefit conferred by Radiation Therapy Oncology Group recursive partitioning analysis Classes 1 and 2. The surgical complication rate was 6.8% while the SRS complication rate was 2.4%. Corticosteroid complications are reported and dependence at 1 month was 20.3%, at 3 months 6.8%, at 6 months 1.7%, and at 12 months no patients remained on corticosteroid therapy. Conclusions: Overall survival and local control with this treatment paradigm compare well to the other published literature. Complications associated with this patient population are low. A corticosteroid tapering protocol is proposed and demonstrated lower rates of steroid-related complications and dependence than previously reported. PMID:24349867

Practical Implementation of Failure Mode and Effects Analysis for Safety and Efficiency in Stereotactic Radiosurgery

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

Younge, Kelly Cooper, E-mail: kyounge@med.umich.edu; Wang, Yizhen; Thompson, John

2015-04-01

Purpose: To improve the safety and efficiency of a new stereotactic radiosurgery program with the application of failure mode and effects analysis (FMEA) performed by a multidisciplinary team of health care professionals. Methods and Materials: Representatives included physicists, therapists, dosimetrists, oncologists, and administrators. A detailed process tree was created from an initial high-level process tree to facilitate the identification of possible failure modes. Group members were asked to determine failure modes that they considered to be the highest risk before scoring failure modes. Risk priority numbers (RPNs) were determined by each group member individually and then averaged. Results: A totalmore » of 99 failure modes were identified. The 5 failure modes with an RPN above 150 were further analyzed to attempt to reduce these RPNs. Only 1 of the initial items that the group presumed to be high-risk (magnetic resonance imaging laterality reversed) was ranked in these top 5 items. New process controls were put in place to reduce the severity, occurrence, and detectability scores for all of the top 5 failure modes. Conclusions: FMEA is a valuable team activity that can assist in the creation or restructuring of a quality assurance program with the aim of improved safety, quality, and efficiency. Performing the FMEA helped group members to see how they fit into the bigger picture of the program, and it served to reduce biases and preconceived notions about which elements of the program were the riskiest.« less

Peripheral nervous system injury after high-dose single-fraction image-guided stereotactic radiosurgery for spine tumors.

PubMed

Stubblefield, Michael D; Ibanez, Katarzyna; Riedel, Elyn R; Barzilai, Ori; Laufer, Ilya; Lis, Eric; Yamada, Yoshiya; Bilsky, Mark H

2017-03-01

OBJECTIVE The object of this study was to determine the percentage of high-dose (1800-2600 cGy) single-fraction stereotactic radiosurgery (SF-SRS) treatments to the spine that result in peripheral nervous system (PNS) injury. METHODS All patients treated with SF-SRS for primary or metastatic spine tumors between January 2004 and May 2013 and referred to the Rehabilitation Medicine Service for evaluation and treatment of neuromuscular, musculoskeletal, or functional impairments or pain were retrospectively identified. RESULTS Five hundred fifty-seven SF-SRS treatments in 447 patients resulted in 14 PNS injuries in 13 patients. All injures resulted from SF-SRS delivered to the cervical or lumbosacral spine at 2400 cGy. The overall percentage of SF-SRS treatments resulting in PNS injury was 2.5%, increasing to 4.5% when the thoracic spine was excluded from analysis. The median time to symptom onset following SF-SRS was 10 months (range 4-32 months). The plexus (cervical, brachial, and/or lumbosacral) was affected clinically and/or electrophysiologically in 12 (86%) of 14 cases, the nerve root in 2 (14%) of 14, and both in 6 (43%) of 14 cases. All patients experienced pain and most (93%) developed weakness. Peripheral nervous system injuries were CTCAE Grade 1 in 14% of cases, 2 in 64%, and 3 in 21%. No dose relationship between SF-SRS dose and PNS injury was detected. CONCLUSIONS Single-fraction SRS to the spine can result in PNS injury with major implications for function and quality of life.

Stereotactic radiosurgery of World Health Organization grade II and III intracranial meningiomas: treatment results on the basis of a 22-year experience.

PubMed

Pollock, Bruce E; Stafford, Scott L; Link, Michael J; Garces, Yolanda I; Foote, Robert L

2012-02-15

A study was undertaken to define the variables associated with tumor control and survival after single-session stereotactic radiosurgery (SRS) for patients with atypical and malignant intracranial meningiomas. Fifty patients with World Health Organization (WHO) grade II (n = 37) or grade III (n = 13) meningiomas underwent SRS from 1990 to 2008. Most tumors were located in the falx/parasagittal region or cerebral convexities (n = 35, 70%). Twenty patients (40%) had progressing tumors despite prior external beam radiation therapy (EBRT) (median dose, 54.0 grays [Gy]). The median treatment volume was 14.6 cm(3) ; the median tumor margin dose was 15.0 Gy. Seven patients (14%) received concurrent EBRT (median dose, 50.4 Gy). Follow-up (median, 38 months) was censored at last evaluation (n = 28) or death (n = 22). Tumor grade correlated with disease-specific survival (DSS) (hazard ratio [HR], 3.4; P = .008), local tumor control (HR, 2.4; P = .02), and progression-free survival (PFS) (HR, 2.6; P = .02) on univariate analysis, but not on multivariate analysis. Multivariate analysis showed that having failed EBRT and tumor volume >14.6 cm(3) were negative predictors of DSS and local control (HR, 3.0; P = .02 and HR, 4.4; P = .01; HR, 3.3; P = .001 and HR, 2.3; P = .02;, respectively). Having failed EBRT was a negative predictor of PFS (HR, 3.5; P = .002). Thirteen patients (26%) had radiation-related complications at a median of 6 months after radiosurgery. Tumor progression despite prior EBRT and larger tumor volume are negative predictors of tumor control and survival for patients having SRS for WHO grade II and III intracranial meningiomas. Copyright © 2011 American Cancer Society.

10 CFR 35.605 - Installation, maintenance, adjustment, and repair.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Installation, maintenance, adjustment, and repair. 35.605 Section 35.605 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.605...

10 CFR 35.605 - Installation, maintenance, adjustment, and repair.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Installation, maintenance, adjustment, and repair. 35.605 Section 35.605 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.605...

10 CFR 35.605 - Installation, maintenance, adjustment, and repair.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Installation, maintenance, adjustment, and repair. 35.605 Section 35.605 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.605...

10 CFR 35.605 - Installation, maintenance, adjustment, and repair.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Installation, maintenance, adjustment, and repair. 35.605 Section 35.605 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.605...

10 CFR 35.605 - Installation, maintenance, adjustment, and repair.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Installation, maintenance, adjustment, and repair. 35.605 Section 35.605 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.605...

Comparison of WBRT alone, SRS alone, and their combination in the treatment of one or more brain metastases: Review and meta-analysis.

PubMed

Khan, Muhammad; Lin, Jie; Liao, Guixiang; Li, Rong; Wang, Baiyao; Xie, Guozhu; Zheng, Jieling; Yuan, Yawei

2017-07-01

Whole brain radiotherapy has been a standard treatment of brain metastases. Stereotactic radiosurgery provides more focal and aggressive radiation and normal tissue sparing but worse local and distant control. This meta-analysis was performed to assess and compare the effectiveness of whole brain radiotherapy alone, stereotactic radiosurgery alone, and their combination in the treatment of brain metastases based on randomized controlled trial studies. Electronic databases (PubMed, MEDLINE, Embase, and Cochrane Library) were searched to identify randomized controlled trial studies that compared treatment outcome of whole brain radiotherapy and stereotactic radiosurgery. This meta-analysis was performed using the Review Manager (RevMan) software (version 5.2) that is provided by the Cochrane Collaboration. The data used were hazard ratios with 95% confidence intervals calculated for time-to-event data extracted from survival curves and local tumor control rate curves. Odds ratio with 95% confidence intervals were calculated for dichotomous data, while mean differences with 95% confidence intervals were calculated for continuous data. Fixed-effects or random-effects models were adopted according to heterogeneity. Five studies (n = 763) were included in this meta-analysis meeting the inclusion criteria. All the included studies were randomized controlled trials. The sample size ranged from 27 to 331. In total 202 (26%) patients with whole brain radiotherapy alone, 196 (26%) patients receiving stereotactic radiosurgery alone, and 365 (48%) patients were in whole brain radiotherapy plus stereotactic radiosurgery group. No significant survival benefit was observed for any treatment approach; hazard ratio was 1.19 (95% confidence interval: 0.96-1.43, p = 0.12) based on three randomized controlled trials for whole brain radiotherapy only compared to whole brain radiotherapy plus stereotactic radiosurgery and hazard ratio was 1.03 (95% confidence interval: 0

SU-F-T-212: A Comparison of Treatment Strategies for Intracranial Stereotactic Radiosurgery

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

Lamberton, T; Slater, J; Wroe, A

2016-06-15

Purpose: Stereotactic radiosurgery is an effective and noninvasive treatment for intracranial lesions that uses highly focused radiation beams in a single treatment fraction. The purpose of this study is to investigate the dosimetric differences between the treatment brain metastasis with a proton beam vs. intensity modulated radiation therapy (IMRT). Methods: Ten separate brain metastasis targets where chosen and treatment plans were created for each, using three different strategies: custom proton beam shaping devices, standardized proton beam shaping devices, and IMRT. Each plan was required to satisfy set parameters for providing adequate coverage and minimizing risk to adjacent tissues. The effectivenessmore » of each plan was calculated by comparing the homogeneity index, conformity index, and V12 for each target using a paired one tailed T-test (α=0.05). Specific comparison of the conformity indices was also made using a subcategory containing targets with volume>1cc. Results: There was no significant difference between the homogeneity indices of the three plans (p>0.05), showing that each plan has the capability of adequately covering the targets. There was a statistically significant difference (p<0.01) between the conformity indices of the custom and the standard proton plan, as with the custom proton and IMRT (p<0.01), with custom proton showing stronger conformity to the target in both cases. There was also a statistical difference between the V12 of all three plans (Custom v. Standardized: p=0.02, Custom v. IMRT: p<0.01, Standardized v. IMRT: p<0.01) with custom proton supplying the lowest dose to surrounding tissues. For large targets (volume>1cc) there was no statistical difference between the proton plans and the IMRT treatment for the conformity index. Conclusion: A custom proton plan is the recommended treatment explored in this study as it is the most reliable way of effectively treating the target while sparing the maximum amount of normal

Analysis of the Factors Contributing to Vertebral Compression Fractures After Spine Stereotactic Radiosurgery

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

Boyce-Fappiano, David; Elibe, Erinma; Schultz, Lonni

Purpose: To determine our institutional vertebral compression fracture (VCF) rate after spine stereotactic radiosurgery (SRS) and determine contributory factors. Methods and Materials: Retrospective analysis from 2001 to 2013 at a single institution was performed. With institutional review board approval, electronic medical records of 1905 vertebral bodies from 791 patients who were treated with SRS for the management of primary or metastatic spinal lesions were reviewed. A total of 448 patients (1070 vertebral bodies) with adequate follow-up imaging studies available were analyzed. Doses ranging from 10 Gy in 1 fraction to 60 Gy in 5 fractions were delivered. Computed tomography and magnetic resonancemore » imaging were used to evaluate the primary endpoints of this study: development of a new VCF, progression of an existing VCF, and requirement of stabilization surgery after SRS. Results: A total of 127 VCFs (11.9%; 95% confidence interval [CI] 9.5%-14.2%) in 97 patients were potentially SRS induced: 46 (36%) were de novo, 44 (35%) VCFs progressed, and 37 (29%) required stabilization surgery after SRS. Our rate for radiologic VCF development/progression (excluding patients who underwent surgery) was 8.4%. Upon further exclusion of patients with hematologic malignancies the VCF rate was 7.6%. In the univariate analyses, females (hazard ratio [HR] 1.54, 95% CI 1.01-2.33, P=.04), prior VCF (HR 1.99, 95% CI 1.30-3.06, P=.001), primary hematologic malignancies (HR 2.68, 95% CI 1.68-4.28, P<.001), thoracic spine lesions (HR 1.46, 95% CI 1.02-2.10, P=.02), and lytic lesions had a significantly increased risk for VCF after SRS. On multivariate analyses, prior VCF and lesion type remained contributory. Conclusions: Single-fraction SRS doses of 16 to 18 Gy to the spine seem to be associated with a low rate of VCFs. To the best of our knowledge, this is the largest reported experience analyzing SRS-induced VCFs, with one of the lowest event rates reported.« less

Machine-Specific Magnetic Resonance Imaging Quality Control Procedures for Stereotactic Radiosurgery Treatment Planning

PubMed Central

Taghizadeh, Somayeh; Yang, Claus Chunli; R. Kanakamedala, Madhava; Morris, Bart; Vijayakumar, Srinivasan

2017-01-01

Purpose Magnetic resonance (MR) images are necessary for accurate contouring of intracranial targets, determination of gross target volume and evaluation of organs at risk during stereotactic radiosurgery (SRS) treatment planning procedures. Many centers use magnetic resonance imaging (MRI) simulators or regular diagnostic MRI machines for SRS treatment planning; while both types of machine require two stages of quality control (QC), both machine- and patient-specific, before use for SRS, no accepted guidelines for such QC currently exist. This article describes appropriate machine-specific QC procedures for SRS applications. Methods and materials We describe the adaptation of American College of Radiology (ACR)-recommended QC tests using an ACR MRI phantom for SRS treatment planning. In addition, commercial Quasar MRID3D and Quasar GRID3D phantoms were used to evaluate the effects of static magnetic field (B0) inhomogeneity, gradient nonlinearity, and a Leksell G frame (SRS frame) and its accessories on geometrical distortion in MR images. Results QC procedures found in-plane distortions (Maximum = 3.5 mm, Mean = 0.91 mm, Standard deviation = 0.67 mm, >2.5 mm (%) = 2) in X-direction (Maximum = 2.51 mm, Mean = 0.52 mm, Standard deviation = 0.39 mm, > 2.5 mm (%) = 0) and in Y-direction (Maximum = 13. 1 mm , Mean = 2.38 mm, Standard deviation = 2.45 mm, > 2.5 mm (%) = 34) in Z-direction and < 1 mm distortion at a head-sized region of interest. MR images acquired using a Leksell G frame and localization devices showed a mean absolute deviation of 2.3 mm from isocenter. The results of modified ACR tests were all within recommended limits, and baseline measurements have been defined for regular weekly QC tests. Conclusions With appropriate QC procedures in place, it is possible to routinely obtain clinically useful MR images suitable for SRS treatment planning purposes. MRI examination for SRS planning can benefit from the improved localization and planning possible

Machine-Specific Magnetic Resonance Imaging Quality Control Procedures for Stereotactic Radiosurgery Treatment Planning.

PubMed

Fatemi, Ali; Taghizadeh, Somayeh; Yang, Claus Chunli; R Kanakamedala, Madhava; Morris, Bart; Vijayakumar, Srinivasan

2017-12-18

Purpose Magnetic resonance (MR) images are necessary for accurate contouring of intracranial targets, determination of gross target volume and evaluation of organs at risk during stereotactic radiosurgery (SRS) treatment planning procedures. Many centers use magnetic resonance imaging (MRI) simulators or regular diagnostic MRI machines for SRS treatment planning; while both types of machine require two stages of quality control (QC), both machine- and patient-specific, before use for SRS, no accepted guidelines for such QC currently exist. This article describes appropriate machine-specific QC procedures for SRS applications. Methods and materials We describe the adaptation of American College of Radiology (ACR)-recommended QC tests using an ACR MRI phantom for SRS treatment planning. In addition, commercial Quasar MRID 3D and Quasar GRID 3D phantoms were used to evaluate the effects of static magnetic field (B 0 ) inhomogeneity, gradient nonlinearity, and a Leksell G frame (SRS frame) and its accessories on geometrical distortion in MR images. Results QC procedures found in-plane distortions (Maximum = 3.5 mm, Mean = 0.91 mm, Standard deviation = 0.67 mm, >2.5 mm (%) = 2) in X-direction (Maximum = 2.51 mm, Mean = 0.52 mm, Standard deviation = 0.39 mm, > 2.5 mm (%) = 0) and in Y-direction (Maximum = 13. 1 mm , Mean = 2.38 mm, Standard deviation = 2.45 mm, > 2.5 mm (%) = 34) in Z-direction and < 1 mm distortion at a head-sized region of interest. MR images acquired using a Leksell G frame and localization devices showed a mean absolute deviation of 2.3 mm from isocenter. The results of modified ACR tests were all within recommended limits, and baseline measurements have been defined for regular weekly QC tests. Conclusions With appropriate QC procedures in place, it is possible to routinely obtain clinically useful MR images suitable for SRS treatment planning purposes. MRI examination for SRS planning can benefit from the improved localization and planning

Stereotactic radiosurgery planning of vestibular schwannomas: Is MRI at 3 Tesla geometrically accurate?

PubMed

Schmidt, M A; Wells, E J; Davison, K; Riddell, A M; Welsh, L; Saran, F

2017-02-01

MRI is a mandatory requirement to accurately plan Stereotactic Radiosurgery (SRS) for Vestibular Schwannomas. However, MRI may be distorted due not only to inhomogeneity of the static magnetic field and gradients but also due to susceptibility-induced effects, which are more prominent at higher magnetic fields. We assess geometrical distortions around air spaces and consider MRI protocol requirements for SRS planning at 3 T. Hardware-related distortion and the effect of incorrect shimming were investigated with structured test objects. The magnetic field was mapped over the head on five volunteers to assess susceptibility-related distortion in the naso-oro-pharyngeal cavities (NOPC) and around the internal ear canal (IAC). Hardware-related geometric displacements were found to be less than 0.45 mm within the head volume, after distortion correction. Shimming errors can lead to displacements of up to 4 mm, but errors of this magnitude are unlikely to arise in practice. Susceptibility-related field inhomogeneity was under 3.4 ppm, 2.8 ppm, and 2.7 ppm for the head, NOPC region and IAC region, respectively. For the SRS planning protocol (890 Hz/pixel, approximately 1 mm 3 isotropic), susceptibility-related displacements were less than 0.5 mm (head), and 0.4 mm (IAC and NOPC). Large displacements are possible in MRI examinations undertaken with lower receiver bandwidth values, commonly used in clinical MRI. Higher receiver bandwidth makes the protocol less vulnerable to sub-optimal shimming. The shimming volume and the CT-MR co-registration must be considered jointly. Geometric displacements can be kept under 1 mm in the vicinity of air spaces within the head at 3 T with appropriate setting of the receiver bandwidth, correct shimming and employing distortion correction. © 2017 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

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.

SU-C-BRA-06: Automatic Brain Tumor Segmentation for Stereotactic Radiosurgery Applications

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

Liu, Y; Stojadinovic, S; Jiang, S

Purpose: Stereotactic radiosurgery (SRS), which delivers a potent dose of highly conformal radiation to the target in a single fraction, requires accurate tumor delineation for treatment planning. We present an automatic segmentation strategy, that synergizes intensity histogram thresholding, super-voxel clustering, and level-set based contour evolving methods to efficiently and accurately delineate SRS brain tumors on contrast-enhance T1-weighted (T1c) Magnetic Resonance Images (MRI). Methods: The developed auto-segmentation strategy consists of three major steps. Firstly, tumor sites are localized through 2D slice intensity histogram scanning. Then, super voxels are obtained through clustering the corresponding voxels in 3D with reference to the similaritymore » metrics composited from spatial distance and intensity difference. The combination of the above two could generate the initial contour surface. Finally, a localized region active contour model is utilized to evolve the surface to achieve the accurate delineation of the tumors. The developed method was evaluated on numerical phantom data, synthetic BRATS (Multimodal Brain Tumor Image Segmentation challenge) data, and clinical patients’ data. The auto-segmentation results were quantitatively evaluated by comparing to ground truths with both volume and surface similarity metrics. Results: DICE coefficient (DC) was performed as a quantitative metric to evaluate the auto-segmentation in the numerical phantom with 8 tumors. DCs are 0.999±0.001 without noise, 0.969±0.065 with Rician noise and 0.976±0.038 with Gaussian noise. DC, NMI (Normalized Mutual Information), SSIM (Structural Similarity) and Hausdorff distance (HD) were calculated as the metrics for the BRATS and patients’ data. Assessment of BRATS data across 25 tumor segmentation yield DC 0.886±0.078, NMI 0.817±0.108, SSIM 0.997±0.002, and HD 6.483±4.079mm. Evaluation on 8 patients with total 14 tumor sites yield DC 0.872±0.070, NMI 0.824�

Five-Year Outcomes of High-Dose Single-Fraction Spinal Stereotactic Radiosurgery

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

Moussazadeh, Nelson; Department of Neurological Surgery, Weill Cornell Medical College, New York Presbyterian Hospital, New York, New York; Lis, Eric

Purpose: To characterize local tumor control and toxicity risk in very long-term survivors (>5 years) after high-dose spinal image guided, intensity modulated radiation therapy delivered as single-dose stereotactic radiosurgery (SRS). Previously published spinal SRS outcome analyses have included a heterogeneous population of cancer patients, mostly with short survival. This is the first study reporting the long-term tumor control and toxicity profiles after high-dose single-fraction spinal SRS. Methods and Materials: The study population included all patients treated from June 2004 to July 2009 with single-fraction spinal SRS (dose 24 Gy) who had survived at least 5 years after treatment. The endpoints examined included diseasemore » progression, surgical or radiation retreatment, in-field fracture development, and radiation-associated toxicity, scored using the Radiation Therapy Oncology Group radiation morbidity scoring criteria and the Common Terminology Criteria for Adverse Events, version 4.0. Local control and fracture development were assessed using Kaplan-Meier analysis. Results: Of 278 patients, 31 (11.1%), with 36 segments treated for spinal tumors, survived at least 5 years after treatment and were followed up radiographically and clinically for a median of 6.1 years (maximum 102 months). The histopathologic findings for the 5-year survivors included radiation-resistant metastases in 58%, radiation-sensitive metastases in 22%, and primary bone tumors in 19%. In this selected cohort, 3 treatment failures occurred at a median of 48.6 months, including 2 recurrences in the radiation field and 1 patient with demonstrated progression at the treatment margins. Ten lesions (27.8%) were associated with acute grade 1 cutaneous or gastrointestinal toxicity. Delayed toxicity ≥3 months after treatment included 8 cases (22.2%) of mild neuropathy, 2 (5.6%) of gastrointestinal discomfort, 8 (22.2%) of dermatitides, and 3 (8.3%) of myalgias

10 CFR 35.633 - Full calibration measurements on remote afterloader units.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Full calibration measurements on remote afterloader units. 35.633 Section 35.633 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.633...

10 CFR 35.643 - Periodic spot-checks for remote afterloader units.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Periodic spot-checks for remote afterloader units. 35.643 Section 35.643 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.643 Periodic...

10 CFR 35.633 - Full calibration measurements on remote afterloader units.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Full calibration measurements on remote afterloader units. 35.633 Section 35.633 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.633...

10 CFR 35.643 - Periodic spot-checks for remote afterloader units.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Periodic spot-checks for remote afterloader units. 35.643 Section 35.643 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.643 Periodic...

10 CFR 35.643 - Periodic spot-checks for remote afterloader units.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Periodic spot-checks for remote afterloader units. 35.643 Section 35.643 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.643 Periodic...

10 CFR 35.633 - Full calibration measurements on remote afterloader units.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Full calibration measurements on remote afterloader units. 35.633 Section 35.633 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.633...

10 CFR 35.643 - Periodic spot-checks for remote afterloader units.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Periodic spot-checks for remote afterloader units. 35.643 Section 35.643 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.643 Periodic...

10 CFR 35.633 - Full calibration measurements on remote afterloader units.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Full calibration measurements on remote afterloader units. 35.633 Section 35.633 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.633...

10 CFR 35.633 - Full calibration measurements on remote afterloader units.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Full calibration measurements on remote afterloader units. 35.633 Section 35.633 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.633...

10 CFR 35.657 - Therapy-related computer systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Therapy-related computer systems. 35.657 Section 35.657... Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.657 Therapy-related computer... computer systems in accordance with published protocols accepted by nationally recognized bodies. At a...

10 CFR 35.657 - Therapy-related computer systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Therapy-related computer systems. 35.657 Section 35.657... Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.657 Therapy-related computer... computer systems in accordance with published protocols accepted by nationally recognized bodies. At a...

10 CFR 35.657 - Therapy-related computer systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Therapy-related computer systems. 35.657 Section 35.657... Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.657 Therapy-related computer... computer systems in accordance with published protocols accepted by nationally recognized bodies. At a...

10 CFR 35.657 - Therapy-related computer systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Therapy-related computer systems. 35.657 Section 35.657... Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.657 Therapy-related computer... computer systems in accordance with published protocols accepted by nationally recognized bodies. At a...

10 CFR 35.657 - Therapy-related computer systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Therapy-related computer systems. 35.657 Section 35.657... Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.657 Therapy-related computer... computer systems in accordance with published protocols accepted by nationally recognized bodies. At a...

Dual mode stereotactic localization method and application

DOEpatents

Keppel, Cynthia E.; Barbosa, Fernando Jorge; Majewski, Stanislaw

2002-01-01

The invention described herein combines the structural digital X-ray image provided by conventional stereotactic core biopsy instruments with the additional functional metabolic gamma imaging obtained with a dedicated compact gamma imaging mini-camera. Before the procedure, the patient is injected with an appropriate radiopharmaceutical. The radiopharmaceutical uptake distribution within the breast under compression in a conventional examination table expressed by the intensity of gamma emissions is obtained for comparison (co-registration) with the digital mammography (X-ray) image. This dual modality mode of operation greatly increases the functionality of existing stereotactic biopsy devices by yielding a much smaller number of false positives than would be produced using X-ray images alone. The ability to obtain both the X-ray mammographic image and the nuclear-based medicine gamma image using a single device is made possible largely through the use of a novel, small and movable gamma imaging camera that permits its incorporation into the same table or system as that currently utilized to obtain X-ray based mammographic images for localization of lesions.

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.

Design and implementation of a 3D-MR/CT geometric image distortion phantom/analysis system for stereotactic radiosurgery.

PubMed

Damyanovich, A Z; Rieker, M; Zhang, B; Bissonnette, J-P; Jaffray, D A

2018-03-27

The design, construction and application of a multimodality, 3D magnetic resonance/computed tomography (MR/CT) image distortion phantom and analysis system for stereotactic radiosurgery (SRS) is presented. The phantom is characterized by (1) a 1 × 1 × 1 (cm) 3 MRI/CT-visible 3D-Cartesian grid; (2) 2002 grid vertices that are 3D-intersections of MR-/CT-visible 'lines' in all three orthogonal planes; (3) a 3D-grid that is MR-signal positive/CT-signal negative; (4) a vertex distribution sufficiently 'dense' to characterize geometrical parameters properly, and (5) a grid/vertex resolution consistent with SRS localization accuracy. When positioned correctly, successive 3D-vertex planes along any orthogonal axis of the phantom appear as 1 × 1 (cm) 2 -2D grids, whereas between vertex planes, images are defined by 1 × 1 (cm) 2 -2D arrays of signal points. Image distortion is evaluated using a centroid algorithm that automatically identifies the center of each 3D-intersection and then calculates the deviations dx, dy, dz and dr for each vertex point; the results are presented as a color-coded 2D or 3D distribution of deviations. The phantom components and 3D-grid are machined to sub-millimeter accuracy, making the device uniquely suited to SRS applications; as such, we present it here in a form adapted for use with a Leksell stereotactic frame. Imaging reproducibility was assessed via repeated phantom imaging across ten back-to-back scans; 80%-90% of the differences in vertex deviations dx, dy, dz and dr between successive 3 T MRI scans were found to be  ⩽0.05 mm for both axial and coronal acquisitions, and over  >95% of the differences were observed to be  ⩽0.05 mm for repeated CT scans, clearly demonstrating excellent reproducibility. Applications of the 3D-phantom/analysis system are presented, using a 32-month time-course assessment of image distortion/gradient stability and statistical control chart for 1.5 T and 3 T GE TwinSpeed MRI systems.

Design and implementation of a 3D-MR/CT geometric image distortion phantom/analysis system for stereotactic radiosurgery

NASA Astrophysics Data System (ADS)

Damyanovich, A. Z.; Rieker, M.; Zhang, B.; Bissonnette, J.-P.; Jaffray, D. A.

2018-04-01

The design, construction and application of a multimodality, 3D magnetic resonance/computed tomography (MR/CT) image distortion phantom and analysis system for stereotactic radiosurgery (SRS) is presented. The phantom is characterized by (1) a 1 × 1 × 1 (cm)3 MRI/CT-visible 3D-Cartesian grid; (2) 2002 grid vertices that are 3D-intersections of MR-/CT-visible ‘lines’ in all three orthogonal planes; (3) a 3D-grid that is MR-signal positive/CT-signal negative; (4) a vertex distribution sufficiently ‘dense’ to characterize geometrical parameters properly, and (5) a grid/vertex resolution consistent with SRS localization accuracy. When positioned correctly, successive 3D-vertex planes along any orthogonal axis of the phantom appear as 1 × 1 (cm)2-2D grids, whereas between vertex planes, images are defined by 1 × 1 (cm)2-2D arrays of signal points. Image distortion is evaluated using a centroid algorithm that automatically identifies the center of each 3D-intersection and then calculates the deviations dx, dy, dz and dr for each vertex point; the results are presented as a color-coded 2D or 3D distribution of deviations. The phantom components and 3D-grid are machined to sub-millimeter accuracy, making the device uniquely suited to SRS applications; as such, we present it here in a form adapted for use with a Leksell stereotactic frame. Imaging reproducibility was assessed via repeated phantom imaging across ten back-to-back scans; 80%–90% of the differences in vertex deviations dx, dy, dz and dr between successive 3 T MRI scans were found to be  ⩽0.05 mm for both axial and coronal acquisitions, and over  >95% of the differences were observed to be  ⩽0.05 mm for repeated CT scans, clearly demonstrating excellent reproducibility. Applications of the 3D-phantom/analysis system are presented, using a 32-month time-course assessment of image distortion/gradient stability and statistical control chart for 1.5 T and 3 T GE TwinSpeed MRI

Detector-specific correction factors in radiosurgery beams and their impact on dose distribution calculations.

PubMed

García-Garduño, Olivia A; Rodríguez-Ávila, Manuel A; Lárraga-Gutiérrez, José M

2018-01-01

Silicon-diode-based detectors are commonly used for the dosimetry of small radiotherapy beams due to their relatively small volumes and high sensitivity to ionizing radiation. Nevertheless, silicon-diode-based detectors tend to over-respond in small fields because of their high density relative to water. For that reason, detector-specific beam correction factors ([Formula: see text]) have been recommended not only to correct the total scatter factors but also to correct the tissue maximum and off-axis ratios. However, the application of [Formula: see text] to in-depth and off-axis locations has not been studied. The goal of this work is to address the impact of the correction factors on the calculated dose distribution in static non-conventional photon beams (specifically, in stereotactic radiosurgery with circular collimators). To achieve this goal, the total scatter factors, tissue maximum, and off-axis ratios were measured with a stereotactic field diode for 4.0-, 10.0-, and 20.0-mm circular collimators. The irradiation was performed with a Novalis® linear accelerator using a 6-MV photon beam. The detector-specific correction factors were calculated and applied to the experimental dosimetry data for in-depth and off-axis locations. The corrected and uncorrected dosimetry data were used to commission a treatment planning system for radiosurgery planning. Various plans were calculated with simulated lesions using the uncorrected and corrected dosimetry. The resulting dose calculations were compared using the gamma index test with several criteria. The results of this work presented important conclusions for the use of detector-specific beam correction factors ([Formula: see text] in a treatment planning system. The use of [Formula: see text] for total scatter factors has an important impact on monitor unit calculation. On the contrary, the use of [Formula: see text] for tissue-maximum and off-axis ratios has not an important impact on the dose distribution

Fiducial Marker Placement

MedlinePlus

... such as stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT) , or proton therapy . Fiducial markers are small ... Proton Therapy Stereotactic Radiosurgery (SRS) and Stereotactic Body Radiotherapy (SBRT) Images related to Fiducial Marker Placement Sponsored ...

SU-F-T-582: Small Field Dosimetry in Radiosurgery Collimators with a Stealth Chamber

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

Azcona, J; Barbes, B

2016-06-15

Purpose: The extraction of a reference signal for measuring small fields in scanning mode can be problematic. In this work we describe the use of a transmission chamber in small field dosimetry for radiosurgery collimators and compare TMR curves obtained with stereotactic diode and microionization chamber. Methods: Four radiosurgery cones of diameters 5, 10, 12.5, and 15mm supplied by Elekta Medical were commissioned in a 6MV FFF beam from an Elekta Versa linac. A transmission chamber manufactured by IBA (Stealth chamber) was attached to the lower part of the collimators and used for PDD and profile measurements in scanning modemore » with a Scanditronix stereotactic diode. It was also used for centering the stereotactic diode in the water tank to measure TMR and output factors, by integrating the signal. TMR measurements for all collimators and the OF for the largest collimator were also acquired on a polystyrene PTW 29672 phantom with a PTW PinPoint 3D chamber 0.016 cm3 volume. Results: Measured TMR with diode and microionization chamber agreed very well with differences larger than 1% only for depths above 15cm, except the smaller collimator, for which differences were always smaller than 2%. Calculated TMR were significantly different (up to 7%) from measured TMR. The differences are attributed to the change in response of the diode with depth, because the effective field aperture varies with depth. Furthermore, neglecting the ratio of phantom-scatter factors in the conversion formula also contributes to this difference. OF measured with diode and chamber showed a difference of 3.5%. Conclusion: The transmission chamber overcomes the problem of extracting a reference signal and is of great help for small field commissioning. Calculating TMR from PDD is strongly discouraged. Good agreement was found when comparing measurements of TMR with stereotactic diode in water with measurements with microionization chamber in polystyrene.« less

Comparison of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus a stereotactic boost (WBRT+SRS) for one to three brain metastases.

PubMed

Rades, Dirk; Kueter, Jan-Dirk; Hornung, Dagmar; Veninga, Theo; Hanssens, Patrick; Schild, Steven E; Dunst, Juergen

2008-12-01

The best available treatment of patients with one to three brain metastases is still unclear. This study compared the results of stereotactic radiosurgery (SRS) alone and whole brain radiotherapy (WBRT) plus SRS (WBRT+SRS). Survival (OS), intracerebral control (IC), and local control of treated metastases (LC) were retrospectively analyzed in 144 patients receiving SRS alone (n=93) or WBRT+SRS (n=51). Eight additional potential prognostic factors were evaluated: age, gender, Eastern Cooperative Oncology Group performance score (ECOG-PS), tumor type, number of brain metastases, extracerebral metastases, recursive partitioning analysis (RPA) class, and interval from tumor diagnosis to irradiation. Subgroup analyses were performed for RPA class I and II patients. 1-year-OS was 53% after SRS and 56% after WBRT+SRS (p=0.24). 1-year-IC rates were 51% and 66% (p=0.015), respectively. 1-year-LC rates were 66% and 87% (p=0.003), respectively. On multivariate analyses, OS was associated with age (p=0.004), ECOG-PS (p=0.005), extracerebral metastases (p<0.001), RPA class (p<0.001), and interval from tumor diagnosis to irradiation (p<0.001). IC was associated with interval from tumor diagnosis to irradiation (p=0.004) and almost with treatment (p=0.09), and LC with treatment (p=0.026) and almost with interval (p=0.08). The results of the subgroup analyses were similar to those of the entire cohort. The increase in IC was stronger in RPA class I patients. WBRT+SRS resulted in better IC and LC but not better OS than SRS alone. Because also IC and LC are important end-points, additional WBRT appears justified in patients with one to three brain metastases, in particular in RPA class I patients.

Radiosurgery in the Management of Intractable Mesial Temporal Lobe Epilepsy.

PubMed

Peñagarícano, José; Serletis, Demitre

2015-09-01

Mesial temporal lobe epilepsy (MTLE) describes recurrent seizure activity originating from the depths of the temporal lobe. MTLE patients who fail two trials of medication now require testing for surgical candidacy at an epilepsy center. For these individuals, temporal lobectomy offers the greatest likelihood for seizure-freedom (up to 80-90%); unfortunately, this procedure remains largely underutilized. Moreover, for select patients unable to tolerate open surgery, novel techniques are emerging for selective ablation of the mesial temporal structures, including stereotactic radiosurgery (SRS). We present here a review of SRS as a potential therapy for MTLE, when open surgery is not an option.

10 CFR 35.642 - Periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Periodic spot-checks for teletherapy units. 35.642 Section 35.642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.642 Periodic spot-checks...

10 CFR 35.642 - Periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Periodic spot-checks for teletherapy units. 35.642 Section 35.642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.642 Periodic spot-checks...

10 CFR 35.642 - Periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Periodic spot-checks for teletherapy units. 35.642 Section 35.642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.642 Periodic spot-checks...

10 CFR 35.642 - Periodic spot-checks for teletherapy units.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Periodic spot-checks for teletherapy units. 35.642 Section 35.642 Energy NUCLEAR REGULATORY COMMISSION MEDICAL USE OF BYPRODUCT MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic Radiosurgery Units § 35.642 Periodic spot-checks...

Local control of brain metastases by stereotactic radiosurgery in relation to dose to the tumor margin.

PubMed

Vogelbaum, Michael A; Angelov, Lilyana; Lee, Shih-Yuan; Li, Liang; Barnett, Gene H; Suh, John H

2006-06-01

The maximal tolerated dose (MTD) for stereotactic radiosurgery (SRS) for brain tumors was established by the Radiation Therapy Oncology Group (RTOG) in protocol 90-05, which defined three dose groups based on the maximal tumor diameter. The goal in this retrospective study was to determine whether differences in doses to the margins of brain metastases affect the ability of SRS to achieve local control. Between 1997 and 2003, 202 patients harboring 375 tumors that met study entry criteria underwent SRS for treatment of one or multiple brain metastases. The median overall follow-up duration was 10.7 months (range 3-83 months). A dose of 24 Gy to the tumor margin had a significantly lower risk of local failure than 15 or 18 Gy (p = 0.0005; hazard ratio 0.277, confidence interval [CI] 0.134-0.573), whereas the 15- and 18-Gy groups were not significantly different from each other (p = 0.82) in this regard. The 1-year local control rate was 85% (95% CI 78-92%) in tumors treated with 24 Gy, compared with 49% (CI 30-68%) in tumors treated with 18 Gy and 45% (CI 23-67%) in tumors treated with 15 Gy. Overall patient survival was independent of dose to the tumor margin. Use of the RTOG 90-05 dosing scheme for brain metastases is associated with a variable local control rate. Tumors larger than 2 cm are less effectively controlled than smaller lesions, which can be safely treated with 24 Gy. Prospective evaluations of the relationship between dose to the tumor margin and local control should be performed to confirm these observations.

Radiosurgery and radiotherapy for sacral tumors.

PubMed

Gibbs, Iris C; Chang, Steven D

2003-08-15

Sacral tumors represent a small subset of spinal lesions and typically include chordomas, metastases, other primary bone tumors, and benign schwannomas. Resection is the standard treatment for many sacral tumors, but many types of sacral lesions have the potential for recurrence after excision. In these cases, adjuvant radiotherapy is often beneficial. Although conventional radiotherapy plays an important role in the management of spinal lesions, the radiation doses required for adequate local control of many sacral lesions generally exceed the tolerance doses of normal tissues, thus limiting its definitive role in the management of sacral tumors. Recent advances in the field of stereotactic radiosurgery have allowed precise targeting of the sacrum. In this report the authors review the use of these two forms of radiation treatment and their role in managing sacral tumors.

A Modified Radiosurgery-Based Arteriovenous Malformation Grading Scale and Its Correlation With Outcomes

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

Wegner, Rodney E.; Oysul, Kaan; Pollock, Bruce E.

Purpose: The Pittsburgh radiosurgery-based arteriovenous malformation (AVM) grading scale was developed to predict patient outcomes after radiosurgery and was later modified with location as a two-tiered variable (deep vs. other). The purpose of this study was to test the modified radiosurgery-based AVM score in a separate set of AVM patients managed with radiosurgery. Methods and Materials: The AVM score is calculated as follows: AVM score = (0.1)(volume, cc) + (0.02)(age, years) + (0.5)(location; frontal/temporal/parietal/occipital/intraventricular/corpus callosum/cerebellar = 0, basal ganglia/thalamus/brainstem = 1). Testing of the modified system was performed on 293 patients having AVM radiosurgery from 1992 to 2004 at themore » University of Pittsburgh with dose planning based on a combination of stereotactic angiography and MRI. The median patient age was 38 years, the median AVM volume was 3.3 cc, and 57 patients (19%) had deep AVMs. The median modified AVM score was 1.25. The median patient follow-up was 39 months. Results: The modified AVM scale correlated with the percentage of patients with AVM obliteration without new deficits ({<=}1.00, 62%; 1.01-1.50, 51%; 1.51-2.00, 53%; and >2.00, 32%; F = 11.002, R{sup 2} = 0.8117, p = 0.001). Linear regression also showed a statistically significant correlation between outcome and dose prescribed to the margin (F = 25.815, p <0.001). Conclusions: The modified radiosurgery-based AVM grading scale using location as a two-tiered variable correlated with outcomes when tested on a cohort of patients who underwent both angiography and MRI for dose planning. This system can be used to guide choices among observation, endovascular, surgical, and radiosurgical management strategies for individual AVM patients.« less

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.

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.

Evaluation of the uncertainties in the TLD radiosurgery postal dose system

NASA Astrophysics Data System (ADS)

Campos, L. T.; Leite, S. P.; de Almeida, C. E. V.; Magalhães, L. A. G.

2018-03-01

Stereotactic radiosurgery is a single-fraction radiation therapy procedure for treating intracranial lesions using a stereotactic apparatus and multiple narrow beams delivered through noncoplanar isocentric arcs. To guarantee a high quality standard, a comprehensive Quality Assurance programme is extremely important to ensure that the measured dose is consistent with the tolerance considered to improve treatment quality. The Radiological Science Laboratory operates a postal audit programme in SRT and SRS. The purpose of the programme is to verify the target localization accuracy in known geometry and the dosimetric conditions of the TPS. The programme works in such a way those thermoluminescence dosimeters, consisting of LiF chips, are sent to the centre where they are to be irradiated to a certain dose. The TLD are then returned, where they are evaluated and the absorbed dose is obtained from TLDs readings. The aim of the present work is estimate the uncertainties in the process of dose determination, using experimental data.

Planned Two-Fraction Proton Beam Stereotactic Radiosurgery for High-Risk Inoperable Cerebral Arteriovenous Malformations

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

Hattangadi, Jona A.; Chapman, Paul H.; Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA

2012-06-01

Purpose: To evaluate patients with high-risk cerebral arteriovenous malformations (AVMs), based on eloquent brain location or large size, who underwent planned two-fraction proton stereotactic radiosurgery (PSRS). Methods and Materials: From 1991 to 2009, 59 patients with high-risk cerebral AVMs received two-fraction PSRS. Median nidus volume was 23 cc (range, 1.4-58.1 cc), 70% of cases had nidus volume {>=}14 cc, and 34% were in critical locations (brainstem, basal ganglia). Median AVM score based on age, AVM size, and location was 3.19 (range, 0.9-6.9). Many patients had prior surgery or embolization (40%) or prior PSRS (12%). The most common prescription was 16more » Gy radiobiologic equivalent (RBE) in two fractions, prescribed to the 90% isodose. Results: At a median follow-up of 56.1 months, 9 patients (15%) had total and 20 patients (34%) had partial obliteration. Patients with total obliteration received higher total dose than those with partial or no obliteration (mean dose, 17.6 vs. 15.5 Gy (RBE), p = 0.01). Median time to total obliteration was 62 months (range, 23-109 months), and 5-year actuarial rate of partial or total obliteration was 33%. Five-year actuarial rate of hemorrhage was 22% (95% confidence interval, 12.5%-36.8%) and 14% (n = 8) suffered fatal hemorrhage. Lesions with higher AVM scores were more likely to hemorrhage (p = 0.024) and less responsive to radiation (p = 0.026). The most common complication was Grade 1 headache acutely (14%) and long term (12%). One patient developed a Grade 2 generalized seizure disorder, and two had mild neurologic deficits. Conclusions: High-risk AVMs can be safely treated with two-fraction PSRS, although total obliteration rate is low and patients remain at risk for future hemorrhage. Future studies should include higher doses or a multistaged PSRS approach for lesions more resistant to obliteration with radiation.« less

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

Failure mode and effects analysis based risk profile assessment for stereotactic radiosurgery programs at three cancer centers in Brazil.

PubMed

Teixeira, Flavia C; de Almeida, Carlos E; Saiful Huq, M

2016-01-01

The goal of this study was to evaluate the safety and quality management program for stereotactic radiosurgery (SRS) treatment processes at three radiotherapy centers in Brazil by using three industrial engineering tools (1) process mapping, (2) failure modes and effects analysis (FMEA), and (3) fault tree analysis. The recommendations of Task Group 100 of American Association of Physicists in Medicine were followed to apply the three tools described above to create a process tree for SRS procedure for each radiotherapy center and then FMEA was performed. Failure modes were identified for all process steps and values of risk priority number (RPN) were calculated from O, S, and D (RPN = O × S × D) values assigned by a professional team responsible for patient care. The subprocess treatment planning was presented with the highest number of failure modes for all centers. The total number of failure modes were 135, 104, and 131 for centers I, II, and III, respectively. The highest RPN value for each center is as follows: center I (204), center II (372), and center III (370). Failure modes with RPN ≥ 100: center I (22), center II (115), and center III (110). Failure modes characterized by S ≥ 7, represented 68% of the failure modes for center III, 62% for center II, and 45% for center I. Failure modes with RPNs values ≥100 and S ≥ 7, D ≥ 5, and O ≥ 5 were considered as high priority in this study. The results of the present study show that the safety risk profiles for the same stereotactic radiotherapy process are different at three radiotherapy centers in Brazil. Although this is the same treatment process, this present study showed that the risk priority is different and it will lead to implementation of different safety interventions among the centers. Therefore, the current practice of applying universal device-centric QA is not adequate to address all possible failures in clinical processes at different radiotherapy centers. Integrated approaches to

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

10 CFR 35.652 - Radiation surveys.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Radiation surveys. 35.652 Section 35.652 Energy NUCLEAR... Units, and Gamma Stereotactic Radiosurgery Units § 35.652 Radiation surveys. (a) In addition to the survey requirement in § 20.1501 of this chapter, a person licensed under this subpart shall make surveys...

10 CFR 35.652 - Radiation surveys.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Radiation surveys. 35.652 Section 35.652 Energy NUCLEAR... Units, and Gamma Stereotactic Radiosurgery Units § 35.652 Radiation surveys. (a) In addition to the survey requirement in § 20.1501 of this chapter, a person licensed under this subpart shall make surveys...

10 CFR 35.652 - Radiation surveys.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 1 2014-01-01 2014-01-01 false Radiation surveys. 35.652 Section 35.652 Energy NUCLEAR... Units, and Gamma Stereotactic Radiosurgery Units § 35.652 Radiation surveys. (a) In addition to the survey requirement in § 20.1501 of this chapter, a person licensed under this subpart shall make surveys...

10 CFR 35.652 - Radiation surveys.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 1 2012-01-01 2012-01-01 false Radiation surveys. 35.652 Section 35.652 Energy NUCLEAR... Units, and Gamma Stereotactic Radiosurgery Units § 35.652 Radiation surveys. (a) In addition to the survey requirement in § 20.1501 of this chapter, a person licensed under this subpart shall make surveys...

10 CFR 35.652 - Radiation surveys.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 1 2013-01-01 2013-01-01 false Radiation surveys. 35.652 Section 35.652 Energy NUCLEAR... Units, and Gamma Stereotactic Radiosurgery Units § 35.652 Radiation surveys. (a) In addition to the survey requirement in § 20.1501 of this chapter, a person licensed under this subpart shall make surveys...

Assessment of targeting accuracy of a low-energy stereotactic radiosurgery treatment for age-related macular degeneration

NASA Astrophysics Data System (ADS)

Taddei, Phillip J.; Chell, Erik; Hansen, Steven; Gertner, Michael; Newhauser, Wayne D.

2010-12-01

Age-related macular degeneration (AMD), a leading cause of blindness in the United States, is a neovascular disease that may be controlled with radiation therapy. Early patient outcomes of external beam radiotherapy, however, have been mixed. Recently, a novel multimodality treatment was developed, comprising external beam radiotherapy and concomitant treatment with a vascular endothelial growth factor inhibitor. The radiotherapy arm is performed by stereotactic radiosurgery, delivering a 16 Gy dose in the macula (clinical target volume, CTV) using three external low-energy x-ray fields while adequately sparing normal tissues. The purpose of our study was to test the sensitivity of the delivery of the prescribed dose in the CTV using this technique and of the adequate sparing of normal tissues to all plausible variations in the position and gaze angle of the eye. Using Monte Carlo simulations of a 16 Gy treatment, we varied the gaze angle by ±5° in the polar and azimuthal directions, the linear displacement of the eye ±1 mm in all orthogonal directions, and observed the union of the three fields on the posterior wall of spheres concentric with the eye that had diameters between 20 and 28 mm. In all cases, the dose in the CTV fluctuated <6%, the maximum dose in the sclera was <20 Gy, the dose in the optic disc, optic nerve, lens and cornea were <0.7 Gy and the three-field junction was adequately preserved. The results of this study provide strong evidence that for plausible variations in the position of the eye during treatment, either by the setup error or intrafraction motion, the prescribed dose will be delivered to the CTV and the dose in structures at risk will be kept far below tolerance doses.

Technique of Whole-Sellar Stereotactic Radiosurgery for Cushing Disease: Results from a Multicenter, International Cohort Study.

PubMed

Shepard, Matthew J; Mehta, Gautam U; Xu, Zhiyuan; 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 J; Blas, Kevin; Kondziolka, Douglas; Grills, Inga; Lee, John Y; Martinez-Alvarez, Roberto; Reda, Wael A; Liscak, Roman; Lee, Cheng-Chia; Lunsford, L Dade; Lee Vance, Mary; Sheehan, Jason P

2018-05-18

Stereotactic radiosurgery (SRS) is used to manage patients with Cushing disease (CD) who have failed surgical/medical management. Because many patients with recurrent/persistent CD lack an identifiable adenoma on neuroimaging, whole-sellar SRS has been increasingly used. Thus, we sought to define the outcomes of patients undergoing whole-sellar SRS. An international, multicenter, retrospective cohort design was used to define clinical/endocrine outcomes for patients undergoing whole-sellar SRS for CD. Propensity-score matching was used to compare patients undergoing whole-sellar SRS and patients who underwent discreet adenoma-targeted SRS. A total of 68 patients underwent whole-sellar SRS, with a mean endocrine follow-up of 5.3 years. The mean treatment volume was 2.6 cm 3 , and the mean margin dose was 22.4 Gy. The 5-year actuarial remission rate was 75.9%, and the median time to remission was 12-months. Treatment volumes >1.6 cm 3 were associated with shorter times to remission (P < 0.05). The 5-year recurrence-free survival rate was 86.0%. Decreased margin and maximum treatment doses were associated with recurrence (P < 0.05). New pituitary hormone deficiency occurred in 15 patients (22.7%). An additional 210 patients were identified who underwent adenoma-targeted SRS. There was no difference in remission rate, time to remission, recurrence-free survival or new endocrinopathy development between patients who underwent whole-sellar SRS and those who underwent discreet adenoma-targeted SRS. Whole-sellar GKRS is effective in controlling CD when an adenoma is not clearly defined on imaging or when an invasive adenoma is suspected at the time of initial surgery. Patients who undergo whole-sellar SRS have outcomes and rates of new pituitary hormone deficiency similar to those of patients who undergo discrete adenoma-targeted GKRS. Copyright © 2018 Elsevier Inc. All rights reserved.

Review and comparison of geometric distortion correction schemes in MR images used in stereotactic radiosurgery applications

NASA Astrophysics Data System (ADS)

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

2017-11-01

In Stereotactic Radiosurgery (SRS), MR-images are widely used for target localization and delineation in order to take advantage of the superior soft tissue contrast they exhibit. However, spatial dose delivery accuracy may be deteriorated due to geometric distortions which are partly attributed to static magnetic field inhomogeneity and patient/object-induced chemical shift and susceptibility related artifacts, known as sequence-dependent distortions. Several post-imaging sequence-dependent distortion correction schemes have been proposed which mainly employ the reversal of read gradient polarity. The scope of this work is to review, evaluate and compare the efficacy of two proposed correction approaches. A specially designed phantom which incorporates 947 control points (CPs) for distortion detection was utilized. The phantom was MR scanned at 1.5T using the head coil and the clinically employed pulse sequence for SRS treatment planning. An additional scan was performed with identical imaging parameters except for reversal of read gradient polarity. In-house MATLAB routines were developed for implementation of the signal integration and average-image distortion correction techniques. The mean CP locations of the two MR scans were regarded as the reference CP distribution. Residual distortion was assessed by comparing the corrected CP locations with corresponding reference positions. Mean absolute distortion on frequency encoding direction was reduced from 0.34mm (original images) to 0.15mm and 0.14mm following application of signal integration and average-image methods, respectively. However, a maximum residual distortion of 0.7mm was still observed for both techniques. The signal integration method relies on the accuracy of edge detection and requires 3-4 hours of post-imaging computational time. The average-image technique is a more efficient (processing time of the order of seconds) and easier to implement method to improve geometric accuracy in such

Multidose Stereotactic Radiosurgery (9 Gy × 3) of the Postoperative Resection Cavity for Treatment of Large Brain Metastases

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

Minniti, Giuseppe, E-mail: gminniti@ospedalesantandrea.it; Department of Neurological Sciences, Scientific Institute IRCCS Neuromed, Pozzilli; Esposito, Vincenzo

2013-07-15

Purpose: To evaluate the clinical outcomes with linear accelerator-based multidose stereotactic radiosurgery (SRS) to large postoperative resection cavities in patients with large brain metastases. Methods and Materials: Between March 2005 to May 2012, 101 patients with a single brain metastasis were treated with surgery and multidose SRS (9 Gy × 3) for large resection cavities (>3 cm). The target volume was the resection cavity with the inclusion of a 2-mm margin. The median cavity volume was 17.5 cm{sup 3} (range, 12.6-35.7 cm{sup 3}). The primary endpoint was local control. Secondary endpoints were survival and distant failure rates, cause of death,more » performance measurements, and toxicity of treatment. Results: With a median follow-up of 16 months (range, 6-44 months), the 1-year and 2-year actuarial survival rates were 69% and 34%, respectively. The 1-year and 2-year local control rates were 93% and 84%, with respective incidences of new distant brain metastases of 50% and 66%. Local control was similar for radiosensitive (non-small cell lung cancer and breast cancer) and radioresistant (melanoma and renal cell cancer) brain metastases. On multivariate Cox analysis stable extracranial disease, breast cancer histology, and Karnofsky performance status >70 were associated with significant survival benefit. Brain radionecrosis occurred in 9 patients (9%), being symptomatic in 5 patients (5%). Conclusions: Adjuvant multidose SRS to resection cavity represents an effective treatment option that achieves excellent local control and defers the use of whole-brain radiation therapy in selected patients with large brain metastases.« less

Immunotherapy Combined with Large Fractions of Radiotherapy: Stereotactic Radiosurgery for Brain Metastases—Implications for Intraoperative Radiotherapy after Resection

PubMed Central

Herskind, Carsten; Wenz, Frederik; Giordano, Frank A.

2017-01-01

Brain metastases (BM) affect approximately a third of all cancer patients with systemic disease. Treatment options include surgery, whole-brain radiotherapy, or stereotactic radiosurgery (SRS) while chemotherapy has only limited activity. In cases where patients undergo resection before irradiation, intraoperative radiotherapy (IORT) to the tumor bed may be an alternative modality, which would eliminate the repopulation of residual tumor cells between surgery and postoperative radiotherapy. Accumulating evidence has shown that high single doses of ionizing radiation can be highly efficient in eliciting a broad spectrum of local, regional, and systemic tumor-directed immune reactions. Furthermore, immune checkpoint blockade (ICB) has proven effective in treating antigenic BM and, thus, combining IORT with ICB might be a promising approach. However, it is not known if a low number of residual tumor cells in the tumor bed after resection is sufficient to act as an immunizing event opening the gate for ICB therapies in the brain. Because immunological data on tumor bed irradiation after resection are lacking, a rationale for combining IORT with ICB must be based on mechanistic insight from experimental models and clinical studies on unresected tumors. The purpose of the present review is to examine the mechanisms by which large radiation doses as applied in SRS and IORT enhance antitumor immune activity. Clinical studies on IORT for brain tumors, and on combined treatment of SRS and ICB for unresected BM, are used to assess the safety, efficacy, and immunogenicity of IORT plus ICB and to suggest an optimal treatment sequence. PMID:28791250

Immunotherapy Combined with Large Fractions of Radiotherapy: Stereotactic Radiosurgery for Brain Metastases-Implications for Intraoperative Radiotherapy after Resection.

PubMed

Herskind, Carsten; Wenz, Frederik; Giordano, Frank A

2017-01-01

Brain metastases (BM) affect approximately a third of all cancer patients with systemic disease. Treatment options include surgery, whole-brain radiotherapy, or stereotactic radiosurgery (SRS) while chemotherapy has only limited activity. In cases where patients undergo resection before irradiation, intraoperative radiotherapy (IORT) to the tumor bed may be an alternative modality, which would eliminate the repopulation of residual tumor cells between surgery and postoperative radiotherapy. Accumulating evidence has shown that high single doses of ionizing radiation can be highly efficient in eliciting a broad spectrum of local, regional, and systemic tumor-directed immune reactions. Furthermore, immune checkpoint blockade (ICB) has proven effective in treating antigenic BM and, thus, combining IORT with ICB might be a promising approach. However, it is not known if a low number of residual tumor cells in the tumor bed after resection is sufficient to act as an immunizing event opening the gate for ICB therapies in the brain. Because immunological data on tumor bed irradiation after resection are lacking, a rationale for combining IORT with ICB must be based on mechanistic insight from experimental models and clinical studies on unresected tumors. The purpose of the present review is to examine the mechanisms by which large radiation doses as applied in SRS and IORT enhance antitumor immune activity. Clinical studies on IORT for brain tumors, and on combined treatment of SRS and ICB for unresected BM, are used to assess the safety, efficacy, and immunogenicity of IORT plus ICB and to suggest an optimal treatment sequence.

Repeat Courses of Stereotactic Radiosurgery (SRS), Deferring Whole-Brain Irradiation, for New Brain Metastases After Initial SRS

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

Shultz, David B.; Modlin, Leslie A.; Jayachandran, Priya

Purpose: To report the outcomes of repeat stereotactic radiosurgery (SRS), deferring whole-brain radiation therapy (WBRT), for distant intracranial recurrences and identify factors associated with prolonged overall survival (OS). Patients and Methods: We retrospectively identified 652 metastases in 95 patients treated with 2 or more courses of SRS for brain metastases, deferring WBRT. Cox regression analyzed factors predictive for OS. Results: Patients had a median of 2 metastases (range, 1-14) treated per course, with a median of 2 courses (range, 2-14) of SRS per patient. With a median follow-up after first SRS of 15 months (range, 3-98 months), the median OS from the timemore » of the first and second course of SRS was 18 (95% confidence interval [CI] 15-24) and 11 months (95% CI 6-17), respectively. On multivariate analysis, histology, graded prognostic assessment score, aggregate tumor volume (but not number of metastases), and performance status correlated with OS. The 1-year cumulative incidence, with death as a competing risk, of local failure was 5% (95% CI 4-8%). Eighteen (24%) of 75 deaths were from neurologic causes. Nineteen patients (20%) eventually received WBRT. Adverse radiation events developed in 2% of SRS sites. Conclusion: Multiple courses of SRS, deferring WBRT, for distant brain metastases after initial SRS, seem to be a safe and effective approach. The graded prognostic assessment score, updated at each course, and aggregate tumor volume may help select patients in whom the deferral of WBRT might be most beneficial.« less

Use of Stereotactic Radiosurgery for Brain Metastases From Non-Small Cell Lung Cancer in the United States

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

Halasz, Lia M., E-mail: lhalasz@uw.edu; Harvard Radiation Oncology Program, Harvard Medical School, Boston, Massachusetts; Weeks, Jane C.

2013-02-01

Purpose: The indications for treatment of brain metastases from non-small cell lung cancer (NSCLC) with stereotactic radiosurgery (SRS) remain controversial. We studied patterns, predictors, and cost of SRS use in elderly patients with NSCLC. Methods and Materials: Using the Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we identified patients with NSCLC who were diagnosed with brain metastases between 2000 and 2007. Our cohort included patients treated with radiation therapy and not surgical resection as initial treatment for brain metastases. Results: We identified 7684 patients treated with radiation therapy within 2 months after brain metastases diagnosis, of whom 469 (6.1%) casesmore » had billing codes for SRS. Annual SRS use increased from 3.0% in 2000 to 8.2% in 2005 and varied from 3.4% to 12.5% by specific SEER registry site. After controlling for clinical and sociodemographic characteristics, we found SRS use was significantly associated with increasing year of diagnosis, specific SEER registry, higher socioeconomic status, admission to a teaching hospital, no history of participation in low-income state buy-in programs (a proxy for Medicaid eligibility), no extracranial metastases, and longer intervals from NSCLC diagnosis. The average cost per patient associated with radiation therapy was 2.19 times greater for those who received SRS than for those who did not. Conclusions: The use of SRS in patients with metastatic NSCLC increased almost 3-fold from 2000 to 2005. In addition, we found significant variations in SRS use across SEER registries and socioeconomic quartiles. National practice patterns in this study suggested both a lack of consensus and an overall limited use of the approach among elderly patients before 2008.« less

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

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.

Frameless Stereotactic Radiosurgery for Treatment of Multiple Sclerosis-Related Trigeminal Neuralgia.

PubMed

Conti, Alfredo; Pontoriero, Antonio; Iatì, Giuseppe; Esposito, Felice; Siniscalchi, Enrico Nastro; Crimi, Salvatore; Vinci, Sergio; Brogna, Anna; De Ponte, Francesco; Germanò, Antonino; Pergolizzi, Stefano; Tomasello, Francesco

2017-07-01

Trigeminal neuralgia (TN) affects 7% of patients with multiple sclerosis (MS). In such patients, TN is difficult to manage either pharmacologically and surgically. Radiosurgical rhizotomy is an effective treatment option. The nonisocentric geometry of radiation beams of CyberKnife introduces new concepts in the treatment of TN. Its efficacy for MS-related TN has not yet been demonstrated. Twenty-seven patients with refractory TN and MS were treated. A nonisocentric beams distribution was chosen; the maximal target dose was 72.5 Gy. The maximal dose to the brainstem was <12 Gy. Effects on pain, medications, sensory disturbance, rate, and time of pain recurrence were analyzed. Median follow-up was 37 (18-72) months. Barrow Neurological Institute pain scale score I-III was achieved in 23/27 patients (85%) within 45 days. Prescription isodose line (80%) accounting for a dose of 58 Gy incorporated an average of 4.85 mm (4-6 mm) of the nerve and mean nerve volume of 26.4 mm 3 (range 20-38 mm 3 ). Seven out of 27 patients (26%) had mild, not bothersome, facial numbness (Barrow Neurological Institute numbness score II). The rate of pain control decreased progressively after the first year, and only 44% of patients retained pain control 4 years later. Frameless radiosurgery can be effectively used to perform retrogasserian rhizotomy. Pain relief was satisfactory and, with our dose/volume constraints, no sensory complications were recorded. Nonetheless, long-term pain control was possible in less than half of the patients. This is a limitation that CyberKnife radiosurgery shares with other techniques in MS patients. Copyright © 2017 Elsevier Inc. All rights reserved.

A Multi-institutional Study of Factors Influencing the Use of Stereotactic Radiosurgery for Brain Metastases

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

Hodgson, David C., E-mail: David.Hodgson@rmp.uhn.on.ca; Department of Radiation Oncology, University of Toronto, Toronto, Ontario; Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario

2013-02-01

Purpose: Stereotactic radiosurgery (SRS) for brain metastases is a relatively well-studied technology with established guidelines regarding patient selection, although its implementation is technically complex. We evaluated the extent to which local availability of SRS affected the treatment of patients with brain metastases. Methods and Materials: We identified 3030 patients who received whole-brain radiation therapy (WBRT) for brain metastases in 1 of 7 cancer centers in Ontario. Clinical data were abstracted for a random sample of 973 patients. Logistic regression analyses were performed to identify factors associated with the use of SRS as a boost within 4 months following WBRT ormore » at any time following WBRT. Results: Of 898 patients eligible for analysis, SRS was provided to 70 (7.8%) patients at some time during the course of their disease and to 34 (3.8%) patients as a boost following WBRT. In multivariable analyses, factors significantly associated with the use of SRS boost following WBRT were fewer brain metastases (odds ratio [OR] = 6.50), controlled extracranial disease (OR = 3.49), age (OR = 0.97 per year of advancing age), and the presence of an on-site SRS program at the hospital where WBRT was given (OR = 12.34; all P values were <.05). Similarly, availability of on-site SRS was the factor most predictive of the use of SRS at any time following WBRT (OR = 5.98). Among patients with 1-3 brain metastases, good/fair performance status, and no evidence of active extracranial disease, SRS was provided to 40.3% of patients who received WBRT in a hospital that had an on-site SRS program vs 3.0% of patients who received WBRT at a hospital without SRS (P<.01). Conclusions: The availability of on-site SRS is the factor most strongly associated with the provision of this treatment to patients with brain metastases and appears to be more influential than accepted clinical eligibility factors.« less

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

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.

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

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

Kim, G.

2015-06-15

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

Sharpening peripheral dose gradient via beam number enhancement from patient head tilt for stereotactic brain radiosurgery

NASA Astrophysics Data System (ADS)

Chiu, Joshua; Pierce, Marlon; Braunstein, Steve E.; Theodosopoulos, Philip V.; McDermott, Michael W.; Sneed, Penny K.; Ma, Lijun

2016-10-01

Sharp dose fall-off is the hallmark of brain radiosurgery for the purpose of delivering high dose radiation to the target while minimizing peripheral dose to regional normal brain tissue. In this study, a technique was developed to enhance the peripheral dose gradient by magnifying the total number of beams focused toward each isocenter through pre-programmed patient head tilting. This technique was tested in clinical settings on a dedicated brain radiosurgical system (GKPFX, Gamma Knife Perfexion, Elekta Oncology) by comparing dosimetry as well as delivery efficiency for 20 radiosurgical cases previously treated with the system. The 3-fold beam number enhancement (BNE) treatment plans were found to produce nearly identical target volume coverage (absolute value  <  0.5%, P  >  0.2) and dose conformity (BNE CI  =  1.41  ±  0.22 versus 1.41  ±  0.11, P  >  0.99) as the original treatment plans. The total beam-on time for the 3-fold BNE treatment plans were also found to be comparable (<0.5 min or 2%) with those of the original treatment plans for all the cases. However, BNE treatment plans significantly improved the mean gradient index (BNE GI  =  2.94  ±  0.27 versus original GI  =  2.98  ±  0.28 P  <  0.0001) and low-level isodose volumes, e.g. 20-50% prescribed isodose volumes, by 1.7%-3.9% (P  <  0.03). With further 4-5-fold increase in the total number of beams, the absolute gradient index can decrease by as much as  -0.5 in absolute value or  -20% for a treatment. In conclusion, BNE via patient head tilt has been demonstrated to be a clinically suitable and efficient technique for physically sharpening the peripheral dose gradient for brain radiosurgery. This work was presented in part at the 2015 ISRS Congress in Yokohama Japan.

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

SU-E-T-438: Frameless Cranial Stereotactic Radiosurgery Immobilization Effectiveness Evaluation

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

Tseng, T; Green, S; Sheu, R

Purpose: To evaluate immobilization effectiveness of Brainlab frameless mask in cranial stereotactic radiosurgery (SRS). Methods: Two sets of setup images were collected pre-and post-treatment for 24 frameless SRS cases. The pre-treatment images were obtained after applying 2D-2D kV image-guided shifts with patients in treatment position and approved by physicians; the post-treatment images were taken immediately after treatment completion. All cases were treated on a Novalis linac with ExacTrac positioning system and Exact Couch. The two image sets were compared with the correctional shifts measured by ExacTrac 6D auto-fusion. The shift differences were considered patient motion within the frameless mask andmore » were used to evaluate its effectiveness for immobilization. Two-tailed paired t-test was applied for significance comparison. Results: The correctional shifts (mean±STD, median) of pre-and post-treatment images were 0.33±0.27mm, 0.26mm and 0.34±0.27mm, 0.23mm (p=0.740) in lateral direction; 0.32±0.29mm, 0.22mm and 0.48±0.30mm, 0.50mm (p=0.012) in longitudinal direction; 0.31±0.22mm, 0.24mm and 0.33±0.21mm, 0.36mm (p=0.623) in vertical direction. The radial correctional shifts (mean±STD, median) of pre -and post-treatment images were 0.60±0.38mm, 0.45mm and 0.75±0.31mm, 0.66mm (p=0.033). The shift differences (mean±STD, median, maximum) were 0.35±0.28mm, 0.3mm, 1.05mm, 0.34±0.28mm, 0.3mm, 1.00mm, 0.24±0.15mm, 0.21mm, 0.60mm and 0.61±0.32mm, 0.57mm, 1.40mm in lateral, longitudinal, vertical and radial direction, respectively. Two shifts greater than 1 mm (1.06mm and 1.02mm) were acquired from post-treatment images. However, the shift differences were only 0.09 and 0.19mm for these two shifts. Two patients with shift differences greater than 1mm (1.05 and 1.04mm) were observed and didn’t coincide with those two who had post-correctional shifts greater than 1mm. Conclusion: Image-guided SRS allowed us to set up patients with sub

SU-G-JeP1-01: A Combination of Real Time Electromagnetic Localization and Tracking with Cone Beam Computed Tomography in Stereotactic Radiosurgery for Brain Tumors

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

Muralidhar, K Raja; Pangam, Suresh; Ponaganti, Srinivas

2016-06-15

Purpose: 1. online verification of patient position during treatment using calypso electromagnetic localization and tracking system. 2. Verification and comparison of positional accuracy between cone beam computed tomography and calypso system. 3. Presenting the advantage of continuation localization in Stereotactic radiosurgery treatments. Methods: Ten brain tumor cases were taken for this study. Patients with head mask were under gone Computed Tomography (CT). Before scanning, mask was cut on the fore head area to keep surface beacons on the skin. Slice thickness of 0.65 mm were taken for this study. x, y, z coordinates of these beacons in TPS were enteredmore » into tracking station. Varian True Beam accelerator, equipped with On Board Imager was used to take Cone beam Computed Tomography (CBCT) to localize the patient. Simultaneously Surface beacons were used to localize and track the patient throughout the treatment. The localization values were compared in both systems. For localization CBCT considered as reference. Tracking was done throughout the treatment using Calypso tracking system using electromagnetic array. This array was in tracking position during imaging and treatment. Flattening Filter free beams of 6MV photons along with Volumetric Modulated Arc Therapy was used for the treatment. The patient movement was observed throughout the treatment ranging from 2 min to 4 min. Results: The average variation observed between calypso system and CBCT localization was less than 0.5 mm. These variations were due to manual errors while keeping beacon on the patient. Less than 0.05 cm intra-fraction motion was observed throughout the treatment with the help of continuous tracking. Conclusion: Calypso target localization system is one of the finest tools to perform radiosurgery in combination with CBCT. This non radiographic method of tracking is a real beneficial method to treat patients confidently while observing real-time motion information of the patient.« less

SU-E-CAMPUS-T-01: Automation of the Winston-Lutz Test for Stereotactic Radiosurgery

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

Litzenberg, D; Irrer, J; Kessler, M

Purpose: To optimize clinical efficiency and shorten patient wait time by minimizing the time and effort required to perform the Winston-Lutz test before stereotactic radiosurgery (SRS) through automation of the delivery, analysis, and documentation of results. Methods: The radiation fields of the Winston-Lutz (WL) test were created in a “machine-QA patient” saved in ARIA for use before SRS cases. Images of the BRW target ball placed at mechanical isocenter are captured with the portal imager for each of four, 2cm×2cm, MLC-shaped beams. When the WL plan is delivered and closed, this event is detected by in-house software called EventNet whichmore » automates subsequent processes with the aid of the ARIA web services. Images are automatically retrieved from the ARIA database and analyzed to determine the offset of the target ball from radiation isocenter. The results are posted to a website and a composite summary image of the results is pushed back into ImageBrowser for review and authenticated documentation. Results: The total time to perform the test was reduced from 20-25 minutes to less than 4 minutes. The results were found to be more accurate and consistent than the previous method which used radiochromic film. The images were also analyzed with DoseLab for comparison. The difference between the film and automated WL results in the X and Y direction and the radius were (−0.17 +/− 0.28) mm, (0.21 +/− 0.20) mm and (−0.14 +/− 0.27) mm, respectively. The difference between the DoseLab and automated WL results were (−0.05 +/− 0.06) mm, (−0.01 +/− 0.02) mm and (0.01 +/− 0.07) mm, respectively. Conclusions: This process reduced patient wait times by 15–20 minutes making the treatment machine available to treat another patient. Accuracy and consistency of results were improved over the previous method and were comparable to other commercial solutions. Access to the ARIA web services is made possible through an Eclipse co

SU-E-T-751: Three-Component Kinetic Model of Tumor Growth and Radiation Response for Stereotactic Radiosurgery

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

Watanabe, Y; Dahlman, E; Leder, K

Purpose: To develop and study a kinetic model of tumor growth and its response to stereotactic radiosurgery (SRS) by assuming that the cells in irradiated tumor volume were made of three types. Methods: A set of ordinary differential equations (ODEs) were derived for three types of cells and a tumor growth rate. It is assumed that the cells were composed of actively proliferating cells, lethally damaged-dividing cells, and non-dividing cells. We modeled the tumor volume growth with a time-dependent growth rate to simulate the saturation of growth. After SRS, the proliferating cells were permanently damaged and converted to the lethallymore » damaged cells. The amount of damaged cells were estimated by the LQ-model. The damaged cells gradually stopped dividing/proliferating and died with a constant rate. The dead cells were cleared from their original location with a constant rate. The total tumor volume was the sum of the three components. The ODEs were numerically solved with appropriate initial conditions for a given dosage. The proposed model was used to model an animal experiment, for which the temporal change of a rhabdomyosarcoma tumor volume grown in a rat was measured with time resolution sufficient to test the model. Results: To fit the model to the experimental data, the following characteristics were needed with the model parameters. The α-value in the LQ-model was smaller than the commonly used value; furthermore, it decreased with increasing dose. At the same time, the tumor growth rate after SRS had to increase. Conclusions: The new 3-component model of tumor could simulate the experimental data very well. The current study suggested that the radiation sensitivity and the growth rate of the proliferating tumor cells may change after irradiation and it depended on the dosage used for SRS. These preliminary observations must be confirmed by future animal experiments.« less

Oral Squamous Cell Carcinoma Found Inline with the Fields of Repeat Stereotactic Radiosurgery for Recurrent Trigeminal Neuralgia.

PubMed

Berti, Aldo; Granville, Michelle; Jacobson, Robert E

2018-01-12

A case of an extremely healthy, active, 96-year-old patient, nonsmoker, is reviewed. He was initially treated for left V1, V2, and V3 trigeminal neuralgia in 2001, at age 80, with stereotactic radiosurgery (SRS) with a dose of 80 Gy to the left retrogasserian trigeminal nerve. He remained asymptomatic for nine years until his trigeminal pain recurred in 2010. He was first treated medically but was intolerant to increasing doses of carbamazepine and gabapentin. He underwent a second SRS in 2012 with a dose of 65.5 Gy to the same retrogasserian area of the trigeminal nerve, making the total cumulative dose 125.5 Gy. In late 2016, four years after the 2 nd SRS, he was found to have invasive keratinizing squamous cell carcinoma in the left posterior mandibular oral mucosa. Keratinizing squamous cell carcinoma is seen primarily in smokers or associated with the human papillomavirus, neither of which was found in this patient. A review of his two SRS plans shows that the left lower posterior mandibular area was clearly within the radiation fields for both SRS treatments. It is postulated that his cancer developed secondary to the long-term radiation effect with a very localized area being exposed twice to a focused, cumulative, high-dose radiation. There are individual reports in the literature of oral mucositis immediately after radiation for trigeminal neuralgia and the delayed development of malignant tumors, including glioblastoma found after SRS for acoustic neuromas, but there are no reports of delayed malignant tumors developing within the general radiation field. Using repeat SRS is an accepted treatment for recurrent trigeminal neuralgia, but physicians and patients should be aware of the potential effects of higher cumulative radiation effects within the treatment field when patients undergo repeat procedures.

Post-treatment neutrophil-to-lymphocyte ratio predicts for overall survival in brain metastases treated with stereotactic radiosurgery.

PubMed

Chowdhary, Mudit; Switchenko, Jeffrey M; Press, Robert H; Jhaveri, Jaymin; Buchwald, Zachary S; Blumenfeld, Philip A; Marwaha, Gaurav; Diaz, Aidnag; Wang, Dian; Abrams, Ross A; Olson, Jeffrey J; Shu, Hui-Kuo G; Curran, Walter J; Patel, Kirtesh R

2018-05-30

Neutrophil-to-lymphocyte ratio (NLR) is a surrogate for systemic inflammatory response and its elevation has been shown to be a poor prognostic factor in various malignancies. Stereotactic radiosurgery (SRS) can induce a leukocyte-predominant inflammatory response. This study investigates the prognostic impact of post-SRS NLR in patients with brain metastases (BM). BM patients treated with SRS from 2003 to 2015 were retrospectively identified. NLR was calculated from the most recent full blood counts post-SRS. Overall survival (OS) and intracranial outcomes were calculated using the Kaplan-Meier method and cumulative incidence with competing risk for death, respectively. 188 patients with 328 BM treated with SRS had calculable post-treatment NLR values. Of these, 51 (27.1%) had a NLR > 6. The overall median imaging follow-up was 13.2 (14.0 vs. 8.7 for NLR ≤ 6.0 vs. > 6.0) months. Baseline patient and treatment characteristics were well balanced, except for lower rate of ECOG performance status 0 in the NLR > 6 cohort (33.3 vs. 44.2%, p = 0.026). NLR > 6 was associated with worse 1- and 2-year OS: 59.9 vs. 72.9% and 24.6 vs. 43.8%, (p = 0.028). On multivariable analysis, NLR > 6 (HR: 1.53; 95% CI 1.03-2.26, p = 0.036) and presence of extracranial metastases (HR: 1.90; 95% CI 1.30-2.78; p < 0.001) were significant predictors for worse OS. No association was seen with NLR and intracranial outcomes. Post-treatment NLR, a potential marker for post-SRS inflammatory response, is inversely associated with OS in patients with BM. If prospectively validated, NLR is a simple, systemic marker that can be easily used to guide subsequent management.

Tolerance and outcomes of stereotactic radiosurgery combined with anti-programmed cell death-1 (pembrolizumab) for melanoma brain metastases.

PubMed

Nardin, Charlee; Mateus, Christine; Texier, Mathieu; Lanoy, Emilie; Hibat-Allah, Salima; Ammari, Samy; Robert, Caroline; Dhermain, Frederic

2018-04-01

Anti-programmed cell death-1 (anti-PD1) antibodies are currently the first-line treatment for patients with metastatic BRAF wild-type melanoma, alone or combined with the anti-CTLA4 monoclonal antibody, ipilimumab. To date, data on safety and the outcomes of patients treated with the anti-PD1 monoclonal antibodies, pembrolizumab (PB), or nivolumab, combined with stereotactic radiosurgery (SRS), for melanoma brain metastases (MBM) are scarce. We retrospectively reviewed all patients with MBM treated with PB combined with SRS between 2012 and 2015. The primary endpoint was neurotoxicity. The secondary endpoints were local, distant intracranial controls and overall survival (OS). Among 74 patients with MBM treated with SRS, 25 patients with a total of 58 MBM treated with PB combined with SRS within 6 months were included. Radiation necrosis, occurring within a median time of 6.5 months, was observed for four MBM (6.8%) in four patients. No other significant SRS-related adverse event was observed. After a median follow-up of 8.4 months, local control was achieved in 46 (80%) metastases and 17 (68%) patients. Perilesional oedema and intratumour haemorrhage appearing or increasing after SRS were associated with local progression (P<0.001). The median OS was 15.3 months (95% confidence interval: 4.6-26). The timing between SRS and PB administration did not seem to influence the risk of radiation necrosis, intracranial control or OS. SRS combined with PB was well tolerated and achieved local control in 80% of the lesions. Prolonged OS was observed compared with that currently yielded in this population of patients. Prospective studies are required to explore further the optimal ways to combine immunotherapy and SRS.

Water Exchange Rate Constant as a Biomarker of Treatment Efficacy in Patients With Brain Metastases Undergoing Stereotactic Radiosurgery

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

Mehrabian, Hatef, E-mail: hatef.mehrabian@sri.utoronto.ca; Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario; Desmond, Kimberly L.

Purpose: This study was designed to evaluate whether changes in metastatic brain tumors after stereotactic radiosurgery (SRS) can be seen with quantitative MRI early after treatment. Methods and Materials: Using contrast-enhanced MRI, a 3-water-compartment tissue model consisting of intracellular (I), extracellular-extravascular (E), and vascular (V) compartments was used to assess the intra–extracellular water exchange rate constant (k{sub IE}), efflux rate constant (k{sub ep}), and water compartment volume fractions (M{sub 0,I}, M{sub 0,E}, M{sub 0,V}). In this prospective study, 19 patients were MRI-scanned before treatment and 1 week and 1 month after SRS. The change in model parameters between the pretreatment and 1-week posttreatmentmore » scans was correlated to the change in tumor volume between pretreatment and 1-month posttreatment scans. Results: At 1 week k{sub IE} differentiated (P<.001) tumors that had partial response from tumors with stable and progressive disease, and a high correlation (R=−0.76, P<.001) was observed between early changes in the k{sub IE} and tumor volume change 1 month after treatment. Other model parameters had lower correlation (M{sub 0,E}) or no correlation (k{sub ep}, M{sub 0,V}). Conclusions: This is the first study that measured k{sub IE} early after SRS, and it found that early changes in k{sub IE} (1 week after treatment) highly correlated with long-term tumor response and could predict the extent of tumor shrinkage at 1 month after SRS.« less

[Linear accelerator-based stereotactic radiation treatment of patients with medial middle fossa meningiomas].

PubMed

Golanov, A V; Cherekaev, V A; Serova, N K; Pronin, I N; Gorlachev, G E; Kotel'nikova, T M; Podoprigora, A E; Kudriavtseva, P A; Galkin, M V

2010-01-01

Medial middle fossa meningiomas are challenging for neurosurgical treatment. Invasion of cranial nerves and vessels leads to high risk of complications after removal of such meningiomas. Currently methods of conformal stereotactic radiation treatment are applied wider and wider for the discussed lesions. During a 3.5-year period 80 patients with medial middle fossa meningiomas were treated in Burdenko Moscow Neurosurgical Institute using linear accelerator "Novalis". In 31 case radiation treatment was preceded by surgical resection. In majority of patients symptoms included cranial nerve dysfunction: oculomotor disturbances in 62.5%, trigeminal impairment--in 37.5%, visual deficit--in 43.8%, facial nerve palsy--in 1.25%. 74 patients underwent radiotherapy with classical fractioning, 2--in hypofractionated mode and 4 received radiosurgery. In cases of classical fractioning mean marginal dose reached 46.3 Gy during 28-33 fractions, in hypofractioning (7 fractions)--31.5 Gy, in radiosurgery--16.25 Gy. Mean follow-up period was 18.4 months (6-42 months). Control of tumor growth was achieved in 97.5% of cases (78 patients): in 42 (52.5%) lesion shrinked, in 36 (45%) stabilization was observed. Clinical examination revealed improvement of visual function in 15 patients (18%) and deterioration in 2 (2.5%). No new neuropathies were found. Stereotactic radiation treatment is the method of choice for medial anterior and middle fossa meningiomas due to effective control of tumor progression and minimal rate of complications.

The impact of decompression with instrumentation on local failure following spine stereotactic radiosurgery.

PubMed

Miller, Jacob A; Balagamwala, Ehsan H; Berriochoa, Camille A; Angelov, Lilyana; Suh, John H; Benzel, Edward C; Mohammadi, Alireza M; Emch, Todd; Magnelli, Anthony; Godley, Andrew; Qi, Peng; Chao, Samuel T

2017-10-01

OBJECTIVE Spine stereotactic radiosurgery (SRS) is a safe and effective treatment for spinal metastases. However, it is unknown whether this highly conformal radiation technique is suitable at instrumented sites given the potential for microscopic disease seeding. The authors hypothesized that spinal decompression with instrumentation is not associated with increased local failure (LF) following SRS. METHODS A 2:1 propensity-matched retrospective cohort study of patients undergoing SRS for spinal metastasis was conducted. Patients with less than 1 month of radiographic follow-up were excluded. Each SRS treatment with spinal decompression and instrumentation was propensity matched to 2 controls without decompression or instrumentation on the basis of demographic, disease-related, dosimetric, and treatment-site characteristics. Standardized differences were used to assess for balance between matched cohorts. The primary outcome was the 12-month cumulative incidence of LF, with death as a competing risk. Lesions demonstrating any in-field progression were considered LFs. Secondary outcomes of interest were post-SRS pain flare, vertebral compression fracture, instrumentation failure, and any Grade ≥ 3 toxicity. Cumulative incidences analysis was used to estimate LF in each cohort, which were compared via Gray's test. Multivariate competing-risks regression was then used to adjust for prespecified covariates. RESULTS Of 650 candidates for the control group, 166 were propensity matched to 83 patients with instrumentation. Baseline characteristics were well balanced. The median prescription dose was 16 Gy in each cohort. The 12-month cumulative incidence of LF was not statistically significantly different between cohorts (22.8% [instrumentation] vs 15.8% [control], p = 0.25). After adjusting for the prespecified covariates in a multivariate competing-risks model, decompression with instrumentation did not contribute to a greater risk of LF (HR 1.21, 95% CI 0.74-1.98, p

SU-E-T-318: The Effect of Patient Positioning Errors On Target Coverage and Cochlear Dose in Stereotactic Radiosurgery Treatment of Acoustic Neuromas