12 Gy gamma knife radiosurgical volume is a predictor for radiation necrosis in non-AVM intracranial tumors

Korytko, Timothy; Radivoyevitch, Tomas; Colussi, Valdir C.; Wessels, Barry W.; Pillai, K.; Maciunas, Robert J.; Einstein, Douglas B.

doi:10.1016/j.ijrobp.2005.07.980

Cited by 267 publications

(211 citation statements)

References 16 publications

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“…Although the clinical significance of this larger low dose volume is unknown, the volume receiving 12 Gy in a single fraction has been demonstrated to predict for both asymptomatic and symptomatic radionecrosis. 11,12 We found that the volume of brain receiving 12 Gy is substantially smaller with Gamma Knife than with VMAT or TomoTherapy treatment. Although the total volume receiving 12 Gy appears to predict toxicity, it is unknown if this risk differs when comparing 1 contiguous volume versus several smaller volumes whose sum is equivalent to the single larger volume.…”

Section: Discussionmentioning

confidence: 87%

Hippocampal-sparing and target volume coverage in treating 3 to 10 brain metastases: A comparison of Gamma Knife, single-isocenter VMAT, CyberKnife, and TomoTherapy stereotactic radiosurgery

Zhang

Antone

et al. 2017

Practical Radiation Oncology

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Section: Discussionmentioning

confidence: 87%

Hippocampal-sparing and target volume coverage in treating 3 to 10 brain metastases: A comparison of Gamma Knife, single-isocenter VMAT, CyberKnife, and TomoTherapy stereotactic radiosurgery

Zhang

Antone

et al. 2017

Practical Radiation Oncology

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“…This is higher than for the iPlan plans that have been our clinical standard prior to introducing the VMAT technique but since Gamma Knife plans typically use a PTV D max >140% we accepted this higher inhomogeneity to reduce the GI. The risk of radiation necrosis following cranial SRS has been reported in several studies 13, 14, 15, 16, 17, 18. More data are needed to determine if the difference in dose distribution between the planning techniques have potential clinical consequences.…”

Section: Discussionmentioning

confidence: 99%

Institutional experience with SRS VMAT planning for multiple cranial metastases

Ballangrud

Kuo

Happersett

et al. 2018

J Applied Clin Med Phys

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Background and PurposeThis study summarizes the cranial stereotactic radiosurgery (SRS) volumetric modulated arc therapy (VMAT) procedure at our institution.Materials and MethodsVolumetric modulated arc therapy plans were generated for 40 patients with 188 lesions (range 2–8, median 5) in Eclipse and treated on a TrueBeam STx. Limitations of the custom beam model outside the central 2.5 mm leaves necessitated more than one isocenter pending the spatial distribution of lesions. Two to nine arcs were used per isocenter. Conformity index (CI), gradient index (GI) and target dose heterogeneity index (HI) were determined for each lesion. Dose to critical structures and treatment times are reported.ResultsLesion size ranged 0.05–17.74 cm3 (median 0.77 cm3), and total tumor volume per case ranged 1.09–26.95 cm3 (median 7.11 cm3). For each lesion, HI ranged 1.2–1.5 (median 1.3), CI ranged 1.0–2.9 (median 1.2), and GI ranged 2.5–8.4 (median 4.4). By correlating GI to PTV volume a predicted GI = 4/PTV0.2 was determined and implemented in a script in Eclipse and used for plan evaluation. Brain volume receiving 7 Gy (V 7 Gy) ranged 10–136 cm3 (median 42 cm3). Total treatment time ranged 24–138 min (median 61 min).ConclusionsVolumetric modulated arc therapy provide plans with steep dose gradients around the targets and low dose to critical structures, and VMAT treatment is delivered in a shorter time than conventional methods using one isocenter per lesion. To further improve VMAT planning for multiple cranial metastases, better tools to shorten planning time are needed. The most significant improvement would come from better dose modeling in Eclipse, possibly by allowing for customizing the dynamic leaf gap (DLG) for a special SRS model and not limit to one DLG per energy per treatment machine and thereby remove the limitation on the Y‐jaw and allow planning with a single isocenter.

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“…Our findings differ substantially from those of other authors who have evaluated necrosis risk in non-AVM patients based on SRS dose-volume parameters. 3,8,9 Korytko et al reported much higher risk of necrosis in 105 brain metastases treated with Gamma Knife SRS than we observed (Table 7); their incidence of symptomatic necrosis was 24%, 33%, 57%, and 55% for 12-Gy volume 0-4.99, 5-9.99, 10-14.99, and ≥ 15 cm 3 , respectively; adding cases of asymptomatic necrosis, the corresponding rates were 39%, 42%, 57%, and 82%. 8 We had only 4%, 15%, 16%, and 11% risk of ARE and 8%, 28%, 39%, and 23% risk of worst-case ARE for the same 12-Gy volume ranges.…”

Section: Discussionmentioning

confidence: 99%

Adverse radiation effect after stereotactic radiosurgery for brain metastases: incidence, time course, and risk factors

Sneed¹,

Mendez

Hoek

et al. 2015

JNS

265

184

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abbreviatioNs ARE = adverse radiation effect; AVM = arteriovenous malformation; CI = confidence interval; HR = hazard ratio; PACS = picture archiving and communication system; SRS = stereotactic radiosurgery; UCSF = University of California, San Francisco; WBRT = whole-brain radiation therapy. obJect The authors sought to determine the incidence, time course, and risk factors for overall adverse radiation effect (ARE) and symptomatic ARE after stereotactic radiosurgery (SRS) for brain metastases. methods All cases of brain metastases treated from 1998 through 2009 with Gamma Knife SRS at UCSF were considered. Cases with less than 3 months of follow-up imaging, a gap of more than 8 months in imaging during the 1st year, or inadequate imaging availability were excluded. Brain scans and pathology reports were reviewed to ensure consistent scoring of dates of ARE, treatment failure, or both; in case of uncertainty, the cause of lesion worsening was scored as indeterminate. Cumulative incidence of ARE and failure were estimated with the Kaplan-Meier method with censoring at last imaging. Univariate and multivariate Cox proportional hazards analyses were performed. results Among 435 patients and 2200 brain metastases evaluable, the median patient survival time was 17.4 months and the median lesion imaging follow-up was 9.9 months. Calculated on the basis of 2200 evaluable lesions, the rates of treatment failure, ARE, concurrent failure and ARE, and lesion worsening with indeterminate cause were 9.2%, 5.4%, 1.4%, and 4.1%, respectively. Among 118 cases of ARE, approximately 60% were symptomatic and 85% occurred 3-18 months after SRS (median 7.2 months). For 99 ARE cases managed without surgery or bevacizumab, the probabilities of improvement observed on imaging were 40%, 57%, and 76% at 6, 12, and 18 months after onset of ARE. The most important risk factors for ARE included prior SRS to the same lesion (with 20% 1-year risk of symptomatic ARE vs 3%, 4%, and 8% for no prior treatment, prior whole brain radiotherapy [WBRT], or concurrent WBRT) and any of these volume parameters: target, prescription isodose, 12-Gy, or 10-Gy volume. Excluding lesions treated with repeat SRS, the 1-year probabilities of ARE were < 1%, 1%, 3%, 10%, and 14% for maximum diameter 0.3-0.6 cm, 0.7-1.0 cm, 1.1-1.5 cm, 1.6-2.0 cm, and 2.1-5.1 cm, respectively. The 1-year probabilities of symptomatic ARE leveled off at 13%-14% for brain metastases maximum diameter > 2.1 cm, target volume > 1.2 cm 3 , prescription isodose volume > 1.8 cm 3 , 12-Gy volume > 3.3 cm 3 , and 10-Gy volume > 4.3 cm 3 , excluding lesions treated with repeat SRS. On both univariate and multivariate analysis, capecitabine, but not other systemic therapy within 1 month of SRS, appeared to increase ARE risk. For the multivariate analysis considering only metastases with target volume > 1.0 cm 3 , risk factors for ARE included prior SRS, kidney primary tumor, connective tissue disorder, and capecitabine. coNclusioNs Although incidence of ARE after SRS was low overall, risk inc...

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12 Gy gamma knife radiosurgical volume is a predictor for radiation necrosis in non-AVM intracranial tumors

Cited by 267 publications

References 16 publications

Hippocampal-sparing and target volume coverage in treating 3 to 10 brain metastases: A comparison of Gamma Knife, single-isocenter VMAT, CyberKnife, and TomoTherapy stereotactic radiosurgery

Hippocampal-sparing and target volume coverage in treating 3 to 10 brain metastases: A comparison of Gamma Knife, single-isocenter VMAT, CyberKnife, and TomoTherapy stereotactic radiosurgery

Institutional experience with SRS VMAT planning for multiple cranial metastases

Adverse radiation effect after stereotactic radiosurgery for brain metastases: incidence, time course, and risk factors

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