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Hsu EJ, Yan Y, Timmerman RD, Wardak Z, Dan TD, Patel TR, Vo DT, Stojadinovic S. Modeling gamma knife radiosurgical toxicity for multiple brain metastases. Radiother Oncol 2023; 188:109874. [PMID: 37640162 DOI: 10.1016/j.radonc.2023.109874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 07/23/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
BACKGROUND AND PURPOSE Radiation oncology protocols for single fraction radiosurgery recommend setting dosing criteria based on assumed risk of radionecrosis, which can be predicted by the 12 Gy normal brain volume (V12). In this study, we show that tumor surface area (SA) and a simple power-law model using only preplan variables can estimate and minimize radiosurgical toxicity. MATERIALS AND METHODS A 245-patient cohort with 1217 brain metastases treated with single or distributed Gamma Knife sessions was reviewed retrospectively. Univariate and multivariable linear regression models and power-law models determined which modeling parameters best predicted V12. The V12 power-law model, represented by a product of normalized Rx dose Rxn, and tumor longest axial dimension LAD (V12 ∼ Rxn1.5*LAD2), was independently validated using a secondary 63-patient cohort with 302 brain metastases. RESULTS Surface area was the best univariate linear predictor of V12 (adjR2 = 0.770), followed by longest axial dimension (adjR2 = 0.755) and volume (adjR2 = 0.745). The power-law model accounted for 90% variance in V12 for 1217 metastatic lesions (adjR2 = 0.906) and 245 patients (adjR2 = 0.896). The average difference ΔV12 between predicted and measured V12s was (0.28 ± 0.55) cm3 per lesion and (1.0 ± 1.2) cm3 per patient. The power-law predictive capability was validated using a secondary 63-patient dataset (adjR2 = 0.867) with 302 brain metastases (adjR2 = 0.825). CONCLUSION Surface area was the most accurate univariate predictor of V12 for metastatic lesions. We developed a preplan model for brain metastases that can help better estimate radionecrosis risk, determine prescription doses given a target V12, and provide safe dose escalation strategies without the use of any planning software.
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Affiliation(s)
- Eric J Hsu
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA.
| | - Yulong Yan
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Robert D Timmerman
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zabi Wardak
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Tu D Dan
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Toral R Patel
- Department of Neurological Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Dat T Vo
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX, USA
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Halthore A, Fellows Z, Tran A, Deville C, Wright JL, Meyer J, Li H, Sheikh K. Treatment Planning of Bulky Tumors Using Pencil Beam Scanning Proton GRID Therapy. Int J Part Ther 2022; 9:40-49. [PMID: 36721485 PMCID: PMC9875826 DOI: 10.14338/ijpt-22-00028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/02/2022] [Indexed: 12/24/2022] Open
Abstract
Purpose To compare spatially fractionated radiation therapy (GRID) treatment planning techniques using proton pencil-beam-scanning (PBS) and photon therapy. Materials and Methods PBS and volumetric modulated arc therapy (VMAT) GRID plans were retrospectively generated for 5 patients with bulky tumors. GRID targets were arranged along the long axis of the gross tumor, spaced 2 and 3 cm apart, and treated with a prescription of 18 Gy. PBS plans used 2- to 3-beam multiple-field optimization with robustness evaluation. Dosimetric parameters including peak-to-edge ratio (PEDR), ratio of dose to 90% of the valley to dose to 10% of the peak VPDR(D90/D10), and volume of normal tissue receiving at least 5 Gy (V5) and 10 Gy (V10) were calculated. The peak-to-valley dose ratio (PVDR), VPDR(D90/D10), and organ-at-risk doses were prospectively assessed in 2 patients undergoing PBS-GRID with pretreatment quality assurance computed tomography (QACT) scans. Results PBS and VMAT GRID plans were generated for 5 patients with bulky tumors. Gross tumor volume values ranged from 826 to 1468 cm3. Peak-to-edge ratio for PBS was higher than for VMAT for both spacing scenarios (2-cm spacing, P = .02; 3-cm spacing, P = .01). VPDR(D90/D10) for PBS was higher than for VMAT (2-cm spacing, P = .004; 3-cm spacing, P = .002). Normal tissue V5 was lower for PBS than for VMAT (2-cm spacing, P = .03; 3-cm spacing, P = .02). Normal tissue mean dose was lower with PBS than with VMAT (2-cm spacing, P = .03; 3-cm spacing, P = .02). Two patients treated using PBS GRID and assessed with pretreatment QACT scans demonstrated robust PVDR, VPDR(D90/D10), and organs-at-risk doses. Conclusions The PEDR was significantly higher for PBS than VMAT plans, indicating lower target edge dose. Normal tissue mean dose was significantly lower with PBS than VMAT. PBS GRID may result in lower normal tissue dose compared with VMAT plans, allowing for further dose escalation in patients with bulky disease.
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Affiliation(s)
- Aditya Halthore
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Zachary Fellows
- Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Anh Tran
- Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Curtiland Deville
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Jean L. Wright
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Jeffrey Meyer
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Heng Li
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
| | - Khadija Sheikh
- Department of Radiation Oncology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
,Department of Radiation Oncology, The Johns Hopkins Proton Center, Washington, DC, USA
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Stojadinovic S, Yan Y, Leiker A, Ahn C, Wardak Z, Dan T, Nedzi L, Timmerman R, Patel T, Barnett S, Mickey B, Meyer J. Considerations of target surface area and the risk of radiosurgical toxicity. PLoS One 2019; 14:e0224047. [PMID: 31634366 PMCID: PMC6802845 DOI: 10.1371/journal.pone.0224047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/03/2019] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE The goal of this study was to explore conceptual benefits of characterizing delineated target volumes based on surface area and to utilize the concept for assessing risk of therapeutic toxicity in radiosurgery. METHODS AND MATERIALS Four computer-generated targets, a sphere, a cylinder, an ellipsoid and a box, were designed for two distinct scenarios. In the first scenario, all targets had identical volumes, and in the second one, all targets had identical surface areas. High quality stereotactic radiosurgery plans with at least 95% target coverage and selectivity were created for each target in both scenarios. Normal brain volumes V12Gy, V14Gy and V16Gy corresponding to received dose of 12 Gy, 14 Gy and 16 Gy, respectively, were computed and analyzed. Additionally, V12Gy and V14Gy volumes and values for seven prospective toxicity variables were recorded for 100 meningioma patients after Gamma Knife radiosurgery. Multivariable stepwise linear regression and best subset linear regression analyses were performed in two statistical software packages, SAS/STAT and R, respectively. RESULTS In a phantom study, for the constant volume targets, the volumes of 12 Gy, 14 Gy and 16 Gy isodose clouds were the lowest for the spherical target as an expected corollary of the isoperimetric inequality. For the constant surface area targets, a conventional wisdom is confirmed, as the target volume increases the corresponding volumes V12Gy, V14Gy and V16Gy also increase. In the 100-meningioma patient cohort, the best univariate model featured tumor surface area as the most significantly associated variable with both V12Gy and V14Gy volumes, corresponding to the adjusted R2 values of 0.82 and 0.77, respectively. Two statistical methods converged to matching multivariable models. CONCLUSIONS In a univariate model, target surface area is a better predictor of spilled dose to normal tissue than target largest dimension or target volume itself. In complex multivariate models, target surface area is an independent variable for modeling radiosurgical normal tissue toxicity risk.
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Affiliation(s)
- Strahinja Stojadinovic
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Yulong Yan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Andrew Leiker
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Chul Ahn
- Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Zabi Wardak
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Tu Dan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Lucien Nedzi
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Robert Timmerman
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Toral Patel
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Samuel Barnett
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Bruce Mickey
- Department of Neurological Surgery, University of Texas Southwestern Medical Center, Dallas, TX, United States of America
| | - Jeffrey Meyer
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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Sheikh K, Hrinivich WT, Bell LA, Moore JA, Laub W, Viswanathan AN, Yan Y, McNutt TR, Meyer J. Comparison of treatment planning approaches for spatially fractionated irradiation of deep tumors. J Appl Clin Med Phys 2019; 20:125-133. [PMID: 31112629 PMCID: PMC6560243 DOI: 10.1002/acm2.12617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 04/01/2019] [Accepted: 04/27/2019] [Indexed: 12/02/2022] Open
Abstract
Purpose The purpose of this work was to compare the dosimetry and delivery times of 3D‐conformal (3DCRT)‐, volumetric modulated arc therapy (VMAT)‐, and tomotherapy‐based approaches for spatially fractionated radiation therapy for deep tumor targets. Methods Two virtual GRID phantoms were created consisting of 7 “target” cylinders (1‐cm diameter) aligned longitudinally along the tumor in a honey‐comb pattern, mimicking a conventional GRID block, with 2‐cm center‐to‐center spacing (GRID2 cm) and 3‐cm center‐to‐center spacing (GRID3 cm), all contained within a larger cylinder (8 and 10 cm in diameter for the GRID2 cm and GRID3 cm, respectively). In a single patient, a GRID3 cm structure was created within the gross tumor volume (GTV). Tomotherapy, VMAT (6 MV + 6 MV‐flattening‐filter‐free) and multi‐leaf collimator segment 3DCRT (6 MV) plans were created using commercially available software. Two tomotherapy plans were created with field widths (TOMO2.5 cm) 2.5 cm and (TOMO5 cm) 5 cm. Prescriptions for all plans were set to deliver a mean dose of 15 Gy to the GRID targets in one fraction. The mean dose to the GRID target and the heterogeneity of the dose distribution (peak‐to‐valley and peak‐to‐edge dose ratios) inside the GRID target were obtained. The volume of normal tissue receiving 7.5 Gy was determined. Results The peak‐to‐valley ratios for GRID2 cm/GRID3 cm/Patient were 2.1/2.3/2.8, 1.7/1.5/2.8, 1.7/1.9/2.4, and 1.8/2.0/2.8 for the 3DCRT, VMAT, TOMO5 cm, and TOMO2.5 cm plans, respectively. The peak‐to‐edge ratios for GRID2 cm/GRID3 cm/Patient were 2.8/3.2/5.4, 2.1/1.8/5.4, 2.0/2.2/3.9, 2.1/2.7/5.2 and for the 3DCRT, VMAT, TOMO5 cm, and TOMO2.5 cm plans, respectively. The volume of normal tissue receiving 7.5 Gy was lowest in the TOMO2.5 cm plan (GRID2 cm/GRID3 cm/Patient = 54 cm3/19 cm3/10 cm3). The VMAT plans had the lowest delivery times (GRID2 cm/GRID3 cm/Patient = 17 min/8 min/9 min). Conclusion Our results present, for the first time, preliminary evidence comparing IMRT‐GRID approaches which result in high‐dose “islands” within a target, mimicking what is achieved with a conventional GRID block but without high‐dose “tail” regions outside of the target. These approaches differ modestly in their ability to achieve high peak‐to‐edge ratios and also differ in delivery times.
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Affiliation(s)
- Khadija Sheikh
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William T Hrinivich
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Leslie A Bell
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Joseph A Moore
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wolfram Laub
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Akila N Viswanathan
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yulong Yan
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Todd R McNutt
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jeffrey Meyer
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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