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Hirano Y, Shinya Y, Hasegawa H, Umekawa M, Iwagami M, Koizumi S, Katano A, Saito N. Sustaining consistent cobalt-60 dose rate enhances radiosurgical outcomes in brain arteriovenous malformation management. Radiother Oncol 2024; 197:110375. [PMID: 38857704 DOI: 10.1016/j.radonc.2024.110375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 04/24/2024] [Accepted: 06/03/2024] [Indexed: 06/12/2024]
Abstract
BACKGROUND AND PURPOSE The impact of cobalt-60 dose rate (Co-60 DR) on outcomes of stereotactic radiosurgery (SRS) for brain arteriovenous malformations (AVMs) remains fully elucidated. This study explored the association between Co-60 DR and SRS outcomes in AVM treatment. MATERIALS AND METHODS 772 AVM patients from 1990 to 2020 were included. High DR was defined as ≥ 2.4 Gy/min. AVM patients were categorized into 3 cohorts based on the nidus volume: small (<5 mL), medium (≥5 mL and < 10 mL), and large (≥10 mL). The primary endpoint was AVM obliteration; secondary endpoints included post-SRS hemorrhage. RESULTS Cumulative obliteration rates of the large AVM were significantly increased in the high DR group than those in the low DR group (84 % vs. 45 % at 5 years, log-rank test; p = 0.011). Multivariable analysis showed that the obliteration rate was significantly elevated for the high DR group in the large AVM cohort with an adjusted hazard ratio (HR) of 1.78 (95 % confidence interval [CI]: 1.00-3.17, p = 0.049). Post-SRS hemorrhage rates of the entire cohort were significantly decreased in the high DR group than in the low DR group (2.5 % vs. 5.3 % at 5 years, log-rank test; p = 0.035). Multivariable analysis revealed post-SRS hemorrhage was reduced in the high DR group with an adjusted HR of 0.47 (95 % CI: 0.24-0.92, p = 0.026). CONCLUSION High DR may lead to increased efficiency for large AVMs and decreased post-SRS hemorrhage in all AVM cases. Sustaining a higher Co-60 DR could potentially yield favorable outcomes for SRS for AVMs.
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Affiliation(s)
- Yudai Hirano
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Yuki Shinya
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan.
| | - Hirotaka Hasegawa
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Motoyuki Umekawa
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Masao Iwagami
- Department of Health Services Research, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Satoshi Koizumi
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Atsuto Katano
- Department of Radiology, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Nobuhito Saito
- Department of Neurosurgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
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Anthes VB, Schwartz M, Cusimano M, Radovanovic I, Kulkarni AV, Laperriere N, Payne D, Heaton R, van Prooijen M, Das S, Tsang DS. Effect of Cobalt-60 Treatment Dose Rate on Arteriovenous Malformation Obliteration After Stereotactic Radiosurgery With Gamma Knife. Neurosurgery 2024; 94:575-583. [PMID: 37796152 DOI: 10.1227/neu.0000000000002701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 08/02/2023] [Indexed: 10/06/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Stereotactic radiosurgery (SRS) marginal dose is associated with successful obliteration of cerebral arteriovenous malformations (AVM). SRS dose rate-how old the cobalt-60 sources are-is known to influence outcomes for some neurological conditions and benign tumors. The objective of this study was to determine the association between cobalt-60 treatment dose rate and cerebral AVM obliteration in patients treated with SRS. METHODS We performed a retrospective cohort study of 361 patients undergoing 411 AVM-directed SRS treatments between 2005 and 2019 at a single institution. Lesion characteristics, SRS details, obliteration dates, and post-treatment toxicities were recorded. Univariate and multivariate regression analyses of AVM outcomes regarding SRS dose rate (range 1.3-3.7 Gy, mean = 2.4 Gy, median = 2.5 Gy) were performed. RESULTS At 10 years post-SRS, 68% of AVMs were obliterated on follow-up imaging. Dose rates >2.9 Gy/min were found to be significantly associated with AVM obliteration compared with those <2.1 Gy/min ( P = .034). AVM size, biologically effective dose, and SRS marginal dose were also associated with obliteration, with obliteration more likely for smaller lesions, higher biologically effective dose, and higher marginal dose. Higher dose rates were not associated with the development of post-SRS radiological or symptomatic edema, although larger AVM volume was associated with both types of edema. CONCLUSION Patients with cerebral AVMs treated with higher SRS dose rates (from newer cobalt-60 sources) experience higher incidences of obliteration without a significant change in the risk of post-treatment edema.
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Affiliation(s)
- Victoria B Anthes
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
| | - Michael Schwartz
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto , Ontario , Canada
| | - Michael Cusimano
- Division of Neurosurgery, St. Michael's Hospital, Unity Health Toronto, Toronto , Ontario , Canada
| | - Ivan Radovanovic
- Division of Neurosurgery, University Health Network, Toronto , Ontario , Canada
| | - Abhaya V Kulkarni
- Division of Neurosurgery, The Hospital for Sick Children, Toronto , Ontario , Canada
| | - Normand Laperriere
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
| | - David Payne
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
| | - Robert Heaton
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
| | - Monique van Prooijen
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
| | - Sunit Das
- Division of Neurosurgery, St. Michael's Hospital, Unity Health Toronto, Toronto , Ontario , Canada
| | - Derek S Tsang
- Radiation Medicine Program, Princess Margaret Cancer Centre and Toronto Western Hospital, University Health Network, Toronto , Ontario , Canada
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Grogan D, Dumot C, Tewari A, Mantziaris G, Dayawansa S, Schlesinger D, Sheehan J. Biologically Effective Dose and Prediction of Obliteration of Arteriovenous Malformations in Pediatric Patients Treated by Gamma Knife Radiosurgery. Neurosurgery 2024; 94:614-621. [PMID: 37830840 DOI: 10.1227/neu.0000000000002717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 08/18/2023] [Indexed: 10/14/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Stereotactic radiosurgery (SRS) represents an effective treatment for pediatric arteriovenous malformations (AVMs). Biological effective dose (BED) has shown promising results in 2 previous studies as a predictive variable for outcomes in adults, but its role has never been studied in pediatric outcomes. METHODS Retrospective data for patients 18 years or younger treated with a single-session SRS for AVMs were collected from 1989 to 2019. BED calculations were performed using an α/β ratio of 2.47. Kaplan-Meier analysis was used to evaluate obliteration, new hemorrhage, and radiation-induced changes (RIC). Cox-regression analysis was used for obliteration prediction using 2 models (margin dose vs BED). RESULTS One hundred ninety-seven patients (median age = 13.1 years, IQR = 5.2) were included; 72.6% (143/197) of them presented initially with spontaneous hemorrhage. A median margin dose of 22 Gy (IQR = 4.0) with a median BED of 183.2 Gy (IQR = 70.54) was used to treat AVM with a median volume of 2.8 cm 3 (IQR = 2.9). After SRS, obliteration was confirmed in 115/197 patients (58.4%) using magnetic resonance imaging and angiography at a median follow-up of 2.85 years (IQR = 2.26). The cumulative obliteration probability was 43.6% (95% CI = 36.1-50.3), 60.5% (95% CI+ = 2.2-67.4), and 66.0% (95% CI = 56.0-73.7) at 3, 5, and 10 years, respectively. In Cox multivariate analysis, a BED >180 Gy (hazard ratio [HR] = 2.11, 95% CI = 1.30-3.40, P = .002) in model 1 and a margin dose >20 Gy (HR = 1.90, 95% CI = 1.15-3.13, P = .019) in model 2 were associated with obliteration. An AVM nidus volume >4 cm 3 was associated with lower obliteration rates in both models. The probability of symptomatic RIC at 10 years was 8.6% (95% CI = 3.5-13.4). Neither BED nor margin dose was associated with RIC occurrence, with the only predictive factor being deep AVM location (HR = 3, 95% CI = 1-9.1, P = .048). CONCLUSION This study confirms BED as a predictor for pediatric AVM obliteration. Optimization of BED in pediatric AVM SRS planning may improve cumulative obliteration rates.
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Affiliation(s)
- Dayton Grogan
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
| | - Chloe Dumot
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
- Department of Neurological Surgery, Hospices civils de Lyon, Lyon , France
| | - Anant Tewari
- University of Virginia School of Medicine, Charlottesville , Virginia , USA
| | - Georgios Mantziaris
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
| | - Sam Dayawansa
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
| | - David Schlesinger
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
- Department of Radiation Oncology, University of Virginia, Charlottesville , Virginia , USA
| | - Jason Sheehan
- Department of Neurological Surgery, University of Virginia, Charlottesville , Virginia , USA
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Zubatkina I, Toma-Dasu I, Dasu A, Levivier M, Tuleasca C, Ivanov P. Clinically Driven Alpha/Beta Ratios for Melanoma Brain Metastases and Investigation of Biologically Effective Dose as a Predictor for Local Control After Radiosurgery: A Proof of Concept in a Retrospective Longitudinal Series of 274 Consecutive Lesions. Neurosurgery 2024; 94:423-430. [PMID: 37665222 DOI: 10.1227/neu.0000000000002639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 06/14/2023] [Indexed: 09/05/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Brain metastases (BM) develop in nearly half of the patients with advanced melanoma. The aim of this retrospective historical cohort study was to analyze radiological response of melanoma BM to single-fraction Gamma Knife radiosurgery (GKRS), in relation to biologically effective dose (BED) for various alpha/beta ratios. METHODS Included in the study were 274 lesions. Primary outcome was local control (LC). Mean marginal dose was 21.6 Gy (median 22, range 15-25). Biologically effective dose was calculated for an alpha/beta ratio of 3 (Gy 3 ), 5 (Gy 10 ), 10 (Gy 10 ), and 15 (Gy 15 ). RESULTS Receiver operating characteristic value for LC and BED was 85% (most statistically significant odds ratio 1.14 for BED Gy 15 , P = .006), while for LC and physical dose was 79% ( P = .02). When comparing equality of 2 receiver operating characteristic areas, this was statistically significant ( P = .02 and .03). Fractional polynomial regression revealed BED (Gy 10 and Gy 15 ) as statistically significant ( P = .05) with BED of more than 63 Gy 10 or 49 Gy 15 as relevant, also for higher probability of quick decrease in volume first month after GKRS and lower probability of radiation necrosis. Shorter irradiation time was associated with better LC ( P = .001), particularly less than 40 minutes (LC below 90%, P = .05). CONCLUSION BED Gy 10 and particularly Gy 15 were more statistically significant than physical dose for LC after GKRS for radioresistant melanoma BM. Irradiation time (per lesion) longer than 40 minutes was predictive for lower rates of LC. Such results need to be validated in larger cohorts.
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Affiliation(s)
- Irina Zubatkina
- Department of Radiosurgery, Stereotactic Radiotherapy and General Oncology Clinic MIBS, Saint Petersburg , Russia
- Peter the Great St. Petersburg Polytechnic University, Saint Petersburg , Russia
| | - Iuliana Toma-Dasu
- Oncology Pathology Department, Karolinska Institutet, Stockholm , Sweden
- Medical Radiation Physics, Stockholm University, Stockholm , Sweden
| | - Alexandru Dasu
- Medical Radiation Sciences, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala , Sweden
| | - Marc Levivier
- Department of Clinical Neurosciences, Neurosurgery Service and Gamma Knife Center, Centre Hospitalier Universitaire Vaudois, Lausanne , Switzerland
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne , Switzerland
| | - Constantin Tuleasca
- Department of Clinical Neurosciences, Neurosurgery Service and Gamma Knife Center, Centre Hospitalier Universitaire Vaudois, Lausanne , Switzerland
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne , Switzerland
- Signal Processing Laboratory (LTS 5), Ecole Polytechnique Fédérale de Lausanne, Lausanne , Switzerland
| | - Pavel Ivanov
- Department of Radiosurgery, Stereotactic Radiotherapy and General Oncology Clinic MIBS, Saint Petersburg , Russia
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Tuleasca C, Carey G, Barriol R, Touzet G, Dubus F, Luc D, Carriere N, Reyns N. Impact of biologically effective dose on tremor decrease after stereotactic radiosurgical thalamotomy for essential tremor: a retrospective longitudinal analysis. Neurosurg Rev 2024; 47:73. [PMID: 38296852 PMCID: PMC10830596 DOI: 10.1007/s10143-024-02296-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/03/2024] [Accepted: 01/14/2024] [Indexed: 02/02/2024]
Abstract
Stereotactic radiosurgery (SRS) is one of the surgical alternatives for drug-resistant essential tremor (ET). Here, we aimed at evaluating whether biologically effective dose (BEDGy2.47) is relevant for tremor improvement after stereotactic radiosurgical thalamotomy in a population of patients treated with one (unplugged) isocenter and a uniform dose of 130 Gy. This is a retrospective longitudinal single center study. Seventy-eight consecutive patients were clinically analyzed. Mean age was 69.1 years (median 71, range 36-88). Mean follow-up period was 14 months (median 12, 3-36). Tremor improvement was assessed at 12 months after SRS using the ET rating assessment scale (TETRAS, continuous outcome) and binary (binary outcome). BED was defined for an alpha/beta of 2.47, based upon previous studies considering such a value for the normal brain. Mean BED was 4573.1 Gy2.47 (median 4612, 4022.1-4944.7). Mean beam-on time was 64.7 min (median 61.4; 46.8-98.5). There was a statically significant correlation between delta (follow-up minus baseline) in TETRAS (total) with BED (p = 0.04; beta coefficient - 0.029) and beam-on time (p = 0.03; beta coefficient 0.57) but also between TETRAS (ADL) with BED (p = 0.02; beta coefficient 0.038) and beam-on time (p = 0.01; beta coefficient 0.71). Fractional polynomial multivariate regression suggested that a BED > 4600 Gy2.47 and a beam-on time > 70 min did not further increase clinical efficacy (binary outcome). Adverse radiation events (ARE) were defined as larger MR signature on 1-year follow-up MRI and were present in 7 out of 78 (8.9%) cases, receiving a mean BED of 4650 Gy2.47 (median 4650, range 4466-4894). They were clinically relevant with transient hemiparesis in 5 (6.4%) patients, all with BED values higher than 4500 Gy2.47. Tremor improvement was correlated with BED Gy2.47 after SRS for drug-resistant ET. An optimal BED value for tremor improvement was 4300-4500 Gy2.47. ARE appeared for a BED of more than 4500 Gy2.47. Such finding should be validated in larger cohorts.
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Affiliation(s)
- Constantin Tuleasca
- Department of Clinical Neurosciences, Neurosurgery Service and Gamma Knife Center, Lausanne University Hospital (CHUV), Rue du Bugnon 44-46, BH-08, CH-1011, Lausanne, Switzerland.
- Faculty of Biology and Medicine (FBM), University of Lausanne (UNIL), Lausanne, Switzerland.
- Ecole Polytechnique Fédérale de Lausanne (EPFL, LTS-5), Lausanne, Switzerland.
| | - Guillaume Carey
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Romain Barriol
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Gustavo Touzet
- Neurosurgery Department, CHU-Lille, Roger Salengro Hospital, 1, Rue Emile Laine, 59000, Lille, France
| | - Francois Dubus
- Medical Physics Department, University Hospital, Lille, France
| | - Defebvre Luc
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Nicolas Carriere
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Nicolas Reyns
- Neurosurgery Department, CHU-Lille, Roger Salengro Hospital, 1, Rue Emile Laine, 59000, Lille, France
- U1189-ONCO-THAI-Assisted Laser Therapy and Immunotherapy for Oncology, University of Lille, INSERM, CHU-Lille, 59000, Lille, France
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Tuleasca C, Toma-Dasu I, Duroux S, George M, Maire R, Daniel RT, Patin D, Schiappacasse L, Dasu A, Faouzi M, Levivier M. Impact of the Mean Cochlear Biologically Effective Dose on Hearing Preservation After Stereotactic Radiosurgery for Vestibular Schwannoma: A Retrospective Longitudinal Analysis. Neurosurgery 2024; 94:174-182. [PMID: 37431994 PMCID: PMC10695539 DOI: 10.1227/neu.0000000000002609] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 05/19/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Stereotactic radiosurgery (SRS) is a useful alternative for small- to medium-sized vestibular schwannoma. To evaluate whether biologically effective dose (BED Gy2.47 ), calculated for mean (BED Gy2.47 mean) and maximal (BED Gy2.47 max) cochlear dose, is relevant for hearing preservation. METHODS This is a retrospective longitudinal single-center study. Were analyzed 213 patients with useful baseline hearing. Risk of hearing decline was assessed for Gardner-Robertson classes and pure tone average (PTA) loss. The mean follow-up period was 39 months (median 36, 6-84). RESULTS Hearing decline (Gardner-Robertson class) 3 years after SRS was associated with higher cochlear BED Gy2.47 mean (odds ratio [OR] 1.39, P = .009). Moreover, BED Gy2.47 mean was more relevant as compared with BED Gy2.47 max (OR 1.13, P = .04). Risk of PTA loss (continuous outcome, follow-up minus baseline) was significantly corelated with BED Gy2.47 mean at 24 (beta coefficient 1.55, P = .002) and 36 (beta coefficient 2.01, P = .004) months after SRS. Risk of PTA loss (>20 dB vs ≤) was associated with higher BED Gy2.47 mean at 6 (OR 1.36, P = .002), 12 (OR 1.36, P = .007), and 36 (OR 1.37, P = .02) months. Risk of hearing decline at 36 months for the BED Gy2.47 mean of 7-8, 10, and 12 Gy 2.47 was 28%, 57%, and 85%, respectively. CONCLUSION Cochlear BED Gy2.47 mean is relevant for hearing decline after SRS and more relevant as compared with BED Gy2.47 max. Three years after SRS, this was sustained for all hearing decline evaluation modalities. Our data suggest the BED Gy2.47 mean cut-off of ≤8 Gy 2.47 for better hearing preservation rates .
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Affiliation(s)
- Constantin Tuleasca
- Lausanne University Hospital (CHUV), Neurosurgery Service and Gamma Knife Center, Lausanne, Switzerland
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne (EPFL, LTS-5), Lausanne, Switzerland
| | - Iuliana Toma-Dasu
- Oncology Pathology Department, Karolinska Institutet, Stockholm, Sweden
- Medical Radiation Physics, Stockholm University, Stockholm, Sweden
| | - Sebastien Duroux
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne, Switzerland
| | - Mercy George
- ENT Department, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Raphael Maire
- ENT Department, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Roy Thomas Daniel
- Lausanne University Hospital (CHUV), Neurosurgery Service and Gamma Knife Center, Lausanne, Switzerland
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne, Switzerland
| | - David Patin
- Institute of Radiation Physics, Lausanne, Switzerland
| | - Luis Schiappacasse
- Radiation Oncology Department, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Alexandru Dasu
- The Skandion Clinic, Uppsala, Sweden
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Mohamed Faouzi
- Division of Biostatistics, Center for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland
| | - Marc Levivier
- Lausanne University Hospital (CHUV), Neurosurgery Service and Gamma Knife Center, Lausanne, Switzerland
- University of Lausanne (UNIL), Faculty of Biology and Medicine (FBM), Lausanne, Switzerland
- Ecole Polytechnique Fédérale de Lausanne (EPFL, LTS-5), Lausanne, Switzerland
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Hopewell JW, Moore J, Villafuerte CJ, Paddick I, Jones B, Hill MA, Tsang DS. Improving the Accuracy of Biologically Effective Dose Estimates, from a Previously Published Study, After Radiosurgery for Acoustic Neuromas. World Neurosurg 2023; 172:e130-e143. [PMID: 36587897 DOI: 10.1016/j.wneu.2022.12.119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/27/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To recalculate biological effective dose values (BED) for radio-surgical treatments of acoustic neuroma from a previous study. BEDs values were previously overestimated by only using beam-on times in calculations, so excluding the important beam-off-times (when deoxyribonucleic acid repair continues) which contribute to the overall treatment time. Simple BED estimations using a mono-exponential approximation may not always be appropriate but if used should include overall treatment time. METHODS Time intervals between isocenters were estimated. These were especially important for the Gamma Knife Model 4C cases since manual changes significantly increase overall treatment times. Individual treatment parameters, such as iso-center number, beam-on-time, and beam-off-time, were then used to calculate BED values using a more appropriate bi-exponential model that includes fast and slow components of DNA damage repair over a wider time range. RESULTS The revised BED estimates differed significantly from previously published values. The overestimates of BED, obtained using beam-on-time only, varied from 0%-40.3%. BED subclasses, each with a BED range of 5 Gy2.47, indicated that revised values were consistently reduced when compared with originally quoted values, especially for 4C compared with Perfexion cases. Furthermore, subdivision of 4C cases by collimator number further emphasized the impact of scheduled gap times on BED. Further analysis demonstrated important limitations of the mono-exponential model. Target volume was a major confounding factor in the interpretation of the results of this study. CONCLUSIONS BED values should be estimated by including beam-on and beam-off times. Suggestions are provided for more accurate BED estimations in future studies.
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Affiliation(s)
- John W Hopewell
- Green Templeton College, University of Oxford, Oxford, UK; Department of Oncology, University of Oxford, Oxford, UK.
| | - Joshua Moore
- School of Mathematics, Cardiff University, Cardiff, UK
| | | | - Ian Paddick
- Queen Square Gamma Knife Centre, National Hospital for Neurology and Neurosurgery, London, UK
| | - Bleddyn Jones
- Green Templeton College, University of Oxford, Oxford, UK; Department of Oncology, University of Oxford, Oxford, UK
| | - Mark A Hill
- Department of Oncology, University of Oxford, Oxford, UK
| | - Derek S Tsang
- Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
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Alzate JD, Berger A, Bernstein K, Mullen R, Qu T, Silverman JS, Shapiro M, Nelson PK, Raz E, Jafar JJ, Riina HA, Kondziolka D. Preoperative flow analysis of arteriovenous malformations and obliteration response after stereotactic radiosurgery. J Neurosurg 2023; 138:944-954. [PMID: 36057117 DOI: 10.3171/2022.7.jns221008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/11/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Morphological and angioarchitectural features of cerebral arteriovenous malformations (AVMs) have been widely described and associated with outcomes; however, few studies have conducted a quantitative analysis of AVM flow. The authors examined brain AVM flow and transit time on angiograms using direct visual analysis and a computer-based method and correlated these factors with the obliteration response after Gamma Knife radiosurgery. METHODS A retrospective analysis was conducted at a single institution using a prospective registry of patients managed from January 2013 to December 2019: 71 patients were analyzed using a visual method of flow determination and 38 were analyzed using a computer-based method. After comparison and validation of the two methods, obliteration response was correlated to flow analysis, demographic, angioarchitectural, and dosimetric data. RESULTS The mean AVM volume was 3.84 cm3 (range 0.64-19.8 cm3), 32 AVMs (45%) were in critical functional locations, and the mean margin radiosurgical dose was 18.8 Gy (range 16-22 Gy). Twenty-seven AVMs (38%) were classified as high flow, 37 (52%) as moderate flow, and 7 (10%) as low flow. Complete obliteration was achieved in 44 patients (62%) at the time of the study; the mean time to obliteration was 28 months for low-flow, 34 months for moderate-flow, and 47 months for high-flow AVMs. Univariate and multivariate analyses of factors predicting obliteration included AVM nidus volume, age, and flow. Adverse radiation effects were identified in 5 patients (7%), and 67 patients (94%) remained free of any functional deterioration during follow-up. CONCLUSIONS AVM flow analysis and categorization in terms of transit time are useful predictors of the probability of and the time to obliteration. The authors believe that a more quantitative understanding of flow can help to guide stereotactic radiosurgery treatment and set accurate outcome expectations.
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Affiliation(s)
| | | | | | | | | | | | - Maksim Shapiro
- 3Interventional Neuroradiology, NYU Langone Health, New York University, New York, New York
| | - Peter K Nelson
- 3Interventional Neuroradiology, NYU Langone Health, New York University, New York, New York
| | - Eytan Raz
- 3Interventional Neuroradiology, NYU Langone Health, New York University, New York, New York
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Tuleasca C, Vermandel M, Reyns N. Stereotactic Radiosurgery: From a Prescribed Physical Radiation Dose Toward Biologically Effective Dose. Mayo Clin Proc 2021; 96:1114-1116. [PMID: 33958048 DOI: 10.1016/j.mayocp.2021.03.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 11/17/2022]
Affiliation(s)
- Constantin Tuleasca
- Department of Neurosurgery and Neuro-oncology, CHU Lille, France, Department of Clinical Neurosciences, Neurosurgery Service and Gamma Knife Center, Lausanne University Hospital (CHUV), Faculty of Biology and Medicine, University of Lausanne, Switzerland.
| | | | - Nicolas Reyns
- Department of Neurosurgery and Neuro-oncology, CHU Lille, France
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