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Hanvey S, Hackett P, Winch L, Lim E, Laney R, Welsh L. A multi-centre stereotactic radiosurgery planning study of multiple brain metastases using isocentric linear accelerators with 5 and 2.5 mm width multi-leaf collimators, CyberKnife and Gamma Knife. BJR Open 2024; 6:tzae003. [PMID: 38371494 PMCID: PMC10873585 DOI: 10.1093/bjro/tzae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 02/15/2024] [Accepted: 02/15/2024] [Indexed: 02/20/2024] Open
Abstract
Objectives This study compared plans of high definition (HD), 2.5 mm width multi-leaf collimator (MLC), to standard, 5 mm width, isocentric linear accelerator (linacs), CyberKnife (CK), and Gamma Knife (GK) for stereotactic radiosurgery (SRS) techniques on multiple brain metastases. Methods Eleven patients undergoing SRS for multiple brain metastases were chosen. Targets and organs at risk (OARs) were delineated and optimized SRS plans were generated and compared. Results The linacs delivered similar conformity index (CI) values, but the gradient index (GI) for HD MLCs was significantly lower (P-value <.001). Half the OARs received significantly lower dose using HD MLCs. CK delivered a significantly lower CI than HD MLC linac (P-value <.001), but a significantly higher GI (P-value <.001). CI was significantly improved with the HD MLC linac compared to GK (P-value = 4.591 × 10-3), however, GK delivered a significantly lower GI (P-value <.001). OAR dose sparing was similar for the HD MLC TL, CK, and GK. Conclusions Comparing linacs for SRS, the preferred choice is HD MLCs. Similar results were achieved with the HD MLC linac, CK, or GK, with each delivering significant improvements in different aspects of plan quality. Advances in knowledge This article is the first to compare HD and standard width MLC linac plans using a combination of single isocentre volumetric modulated arc therapy and multi-isocentric dynamic conformal arc plans as required, which is a more clinically relevant assessment. Furthermore, it compares these plans with CK and GK, assessing the relative merits of each technique.
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Affiliation(s)
- Scott Hanvey
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
| | | | - Lucy Winch
- University Hospitals Bristol NHS Foundation Trust, Bristol, BS2 8ED, United Kingdom
| | - Elizabeth Lim
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
- University of Plymouth, Plymouth, PL4 8AA, United Kingdom
| | - Robin Laney
- University Hospitals Plymouth NHS Trust, Plymouth, PL6 8DH, United Kingdom
| | - Liam Welsh
- The Royal Marsden, London, SW3 6JJ, United Kingdom
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Agazaryan N, Tenn S, Lee C, Steinberg M, Hegde J, Chin R, Pouratian N, Yang I, Kim W, Kaprealian T. Simultaneous radiosurgery for multiple brain metastases: technical overview of the UCLA experience. Radiat Oncol 2021; 16:221. [PMID: 34789300 PMCID: PMC8597274 DOI: 10.1186/s13014-021-01944-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE/OBJECTIVE(S) To communicate our institutional experience with single isocenter radiosurgery treatments for multiple brain metastases, including challenges with determining planning target volume (PTV) margins and resulting consequences, image-guidance translational and rotational tolerances, intra-fraction patient motion, and prescription considerations with larger PTV margins. MATERIALS/METHODS Eight patient treatments with 51 targets were planned with various margins using Elements Multiple Brain Mets SRS treatment planning software (Brainlab, Munich, Germany). Forty-eight plans with 0 mm, 1 mm and 2 mm margins were created, including plans with variable margins, where targets more than 6 cm away from the isocenter were planned with larger margins. The dosimetric impact of the margins were analyzed with V5Gy, V8Gy, V10Gy, V12Gy values. Additionally, 12 patient motion data were analyzed to determine both the impact of the repositioning threshold and the distributions of the patient translational and rotational movements. RESULTS The V5Gy, V8Gy, V10Gy, V12Gy volumes approximately doubled when margins change from 0 to 1 mm and tripled when change from 0 to 2 mm. With variable margins, the aggregated results are similar to results from plans using the lower of two margins, since only 12.2% of the targets were more than 6 cm away from the isocenter. With 0.5 mm re-positioning threshold, 57.4% of the time the patients are repositioned. Reducing the threshold to 0.25 mm results in 91.7% repositioning rate, due to limitations of the fusion algorithm and actual patient motion. The 90th percentile of translational movements in all directions is 0.7 mm, while the 90th percentile of rotational movements in all directions is 0.6 degrees. Median translations and rotations are 0.2 mm and 0.2 degrees, respectively. CONCLUSIONS Based on the data presented, we have switched our modus operandi from 2 to 1 mm PTV margins, with an eventual goal of using 0.5 and 1.0 mm variable margins when an automated margin assignment method becomes available. The 0.5 mm and 0.5 degrees repositioning thresholds are clinically appropriate with small residual patient movements.
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Affiliation(s)
- Nzhde Agazaryan
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
| | - Steve Tenn
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Chul Lee
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Michael Steinberg
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - John Hegde
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Robert Chin
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Nader Pouratian
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Isaac Yang
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Won Kim
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Tania Kaprealian
- Department of Radiation Oncology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Xu Y, Miao J, Liu Q, Huang P, Ma P, Chen X, Men K, Xiao J, Dai J. Longitudinal Grouping of Target Volumes for Volumetric-Modulated Arc Therapy of Multiple Brain Metastases. Front Oncol 2021; 11:578934. [PMID: 34277388 PMCID: PMC8278313 DOI: 10.3389/fonc.2021.578934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 06/07/2021] [Indexed: 11/30/2022] Open
Abstract
Purpose Treatment of multiple brain metastases with single-isocenter volumetric modulated arc therapy causes unnecessary exposure to normal brain tissue. In this study, a longitudinal grouping method was developed to reduce such unnecessary exposure. Materials and Methods This method has two main aspects: grouping brain lesions longitudinally according to their longitudinal projection positions in beam’s eye view, and rotating the collimator to 90° to make the multiple leaf collimator leaves conform to the targets longitudinally group by group. For 11 patients with multiple (5–30) brain metastases, two single-isocenter volumetric modulated arc therapy plans were generated using a longitudinal grouping strategy (LGS) and the conventional strategy (CVS). The prescription dose was 52 Gy for 13 fractions. Dose normalization to 100% of the prescription dose in 95% of the planning target volume was adopted. For plan quality comparison, Paddick conformity and the gradient index of the planning target volume, and the mean dose, the V100%, V50%, V25%, and V10% volumes of normal brain tissue were calculated. Results There were no significant differences between the LGS and CVS plans in Paddick conformity (p = 0.374) and the gradient index (p = 0.182) of the combined planning target volumes or for V100% (p = 0.266) and V50% (p = 0.155) of the normal brain. However, the V25% and V10% of the normal brain which represented the low-dose region were significantly reduced in the LGS plans (p = 0.004 and p = 0.003, respectively). Consistently, the mean dose of the entire normal brain was 12.04 and 11.17 Gy in the CVS and LGS plans, respectively, a significant reduction in the LGS plans (p = 0.003). Conclusions The longitudinal grouping method can decrease unnecessary exposure and reduces the low-dose range in normal brain tissue.
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Affiliation(s)
- Yingjie Xu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Junjie Miao
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qingfeng Liu
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Peng Huang
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pan Ma
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xinyuan Chen
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Kuo Men
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianping Xiao
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jianrong Dai
- Department of Radiation Oncology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Cullom ET, Xia Y, Chuang KC, Gude ZW, Zlateva Y, Adamson JD, Giles WM. Single isocenter SRS using CAVMAT offers improved robustness to commissioning and treatment delivery uncertainty compared to VMAT. J Appl Clin Med Phys 2021; 22:36-43. [PMID: 34165217 PMCID: PMC8292691 DOI: 10.1002/acm2.13248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 01/12/2021] [Accepted: 03/15/2021] [Indexed: 11/22/2022] Open
Abstract
Purpose In this study, we evaluate and compare single isocenter multiple target VMAT (SIMT) and Conformal Arc Informed VMAT (CAVMAT) radiosurgery's sensitivity to uncertainties in dosimetric leaf gap (DLG) and treatment delivery. CAVMAT is a novel planning technique that uses multiple target conformal arcs as the starting point for limited inverse VMAT optimization. Methods All VMAT and CAVMAT plans were recalculated with DLG values of 0.4, 0.8, and 1.2 mm. DLG effect on V6Gy[cc], V12Gy[cc], and V16Gy[cc], and target dose was evaluated. Plans were delivered to a Delta4 (ScandiDos, Madison, WI) phantom and gamma analysis performed with varying criteria. Log file analysis was performed to evaluate MLC positional error. Sixteen targets were delivered to a SRS MapCHECK (Sun Nuclear Corp., Melbourne, FL) to evaluate VMAT and CAVMAT's dose difference (DD) as a function of DLG. Results VMAT's average maximum and minimum target dose sensitivity to DLG was 9.08 ±3.50%/mm and 9.50 ± 3.30%/mm, compared to 3.20 ± 1.60%/mm and 4.72 ± 1.60%/mm for CAVMAT. For VMAT, V6Gy[cc], V12Gy[cc], and V16Gy[cc] sensitivity was 35.83 ± 9.50%/mm, 34.12 ± 6.60%/mm, and 39.23 ± 8.40%/mm. In comparison, CAVMAT's sensitivity was 23.19 ± 4.50%/mm, 22.45 ± 4.40%/mm, and 24.88 ± 4.90%/mm, respectively. Upon delivery to the Delta4, CAVMAT offered superior dose agreement compared to VMAT. For a 1%/1 mm gamma analysis, VMAT and CAVMAT had a passing rate of 94.53 ± 4.40% and 99.28 ± 1.70%, respectively. CAVMAT was more robust to DLG variation, with the SRS MapCHECK plans yielding an absolute average DD sensitivity of 2.99 ± 1.30%/mm compared to 5.07 ± 1.10%/mm for VMAT. Log files demonstrated minimal differences in MLC positional error for both techniques. Conclusions CAVMAT remains robust to delivery uncertainties while offering a target dose sensitivity to DLG less than half that of VMAT, and 65% of that of VMAT for V6Gy[cc], V12Gy[cc], and V16Gy[cc]. The superior dose agreement and reduced sensitivity of CAVMAT to DLG uncertainties indicate promise as a robust alternative to VMAT for SIMT SRS.
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Affiliation(s)
- Edward T Cullom
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA.,Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Yuqing Xia
- Medical Physics Graduate Program, Duke Kunshan University, Suzhou, China
| | - Kai-Cheng Chuang
- Medical Physics Graduate Program, Duke Kunshan University, Suzhou, China
| | - Zachary W Gude
- Medical Physics Graduate Program, Duke University, Durham, North Carolina, USA
| | - Yana Zlateva
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - Justus D Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
| | - William M Giles
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, USA
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Hanley J, Dresser S, Simon W, Flynn R, Klein EE, Letourneau D, Liu C, Yin FF, Arjomandy B, Ma L, Aguirre F, Jones J, Bayouth J, Holmes T. AAPM Task Group 198 Report: An implementation guide for TG 142 quality assurance of medical accelerators. Med Phys 2021; 48:e830-e885. [PMID: 34036590 DOI: 10.1002/mp.14992] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/16/2021] [Accepted: 04/28/2021] [Indexed: 11/11/2022] Open
Abstract
The charges on this task group (TG) were as follows: (a) provide specific procedural guidelines for performing the tests recommended in TG 142; (b) provide estimate of the range of time, appropriate personnel, and qualifications necessary to complete the tests in TG 142; and (c) provide sample daily, weekly, monthly, or annual quality assurance (QA) forms. Many of the guidelines in this report are drawn from the literature and are included in the references. When literature was not available, specific test methods reflect the experiences of the TG members (e.g., a test method for door interlock is self-evident with no literature necessary). In other cases, the technology is so new that no literature for test methods was available. Given broad clinical adaptation of volumetric modulated arc therapy (VMAT), which is not a specific topic of TG 142, several tests and criteria specific to VMAT were added.
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Affiliation(s)
- Joseph Hanley
- Princeton Radiation Oncology, Monroe, New Jersey, 08831, USA
| | - Sean Dresser
- Winship Cancer Institute, Radiation Oncology, Emory University, Atlanta, Georgia, 30322, USA
| | | | - Ryan Flynn
- Department of Radiation Oncology, University of Iowa, Iowa City, Iowa, 52242, USA
| | - Eric E Klein
- Brown university, Rhode Island Hospital, Providence, Rhode Island, 02905, USA
| | | | - Chihray Liu
- University of Florida, Gainesville, Florida, 32610-0385, USA
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina, 27710, USA
| | - Bijan Arjomandy
- Karmanos Cancer Institute at McLaren-Flint, Flint, Michigan, 48532, USA
| | - Lijun Ma
- Department of Radiation Oncology, University of California San Francisco, San Francisco, 94143-0226, USA
| | | | - Jimmy Jones
- Department of Radiation Oncology, The University of Colorado Health-Poudre Valley, Fort Collins, Colorado, 80525, USA
| | - John Bayouth
- Department of Human Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, 53792-0600, USA
| | - Todd Holmes
- Varian Medical Systems, Palo Alto, California, 94304, USA
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6
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Chea M, Fezzani K, Jacob J, Cuttat M, Croisé M, Simon JM, Feuvret L, Valery CA, Maingon P, Benadjaoud MA, Jenny C. Dosimetric study between a single isocenter dynamic conformal arc therapy technique and Gamma Knife radiosurgery for multiple brain metastases treatment: impact of target volume geometrical characteristics. Radiat Oncol 2021; 16:45. [PMID: 33639959 PMCID: PMC7912819 DOI: 10.1186/s13014-021-01766-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/11/2021] [Indexed: 12/14/2022] Open
Abstract
Purpose To compare linac-based mono-isocentric radiosurgery with Brainlab Elements Multiple Brain Mets (MBM) SRS and the Gamma Knife using a specific statistical method and to analyze the dosimetric impact of the target volume geometric characteristics. A dose fall-off analysis allowed to evaluate the Gradient Index relevancy for the dose spillage characterization. Material and methods Treatments were planned on twenty patients with three to nine brain metastases with MBM 2.0 and GammaPlan 11.0. Ninety-five metastases ranging from 0.02 to 9.61 cc were included. Paddick Index (PI), Gradient Index (GI), dose fall-off, volume of healthy brain receiving more than 12 Gy (V12Gy) and DVH were used for the plan comparison according to target volume, major axis diameter and Sphericity Index (SI). The multivariate regression approach allowed to analyze the impact of each geometric characteristic keeping all the others unchanged. A parallel study was led to evaluate the impact of the isodose line (IDL) prescription on the MBM plan quality. Results For mono-isocentric linac-based radiosurgery, the IDL around 70–75% was the best compromise found. For both techniques, the GI and the dose fall-off decreased with the target volume. In comparison, PI was slightly improved with MBM for targets < 1 cc or SI > 0.78. GI was improved with GP for targets < 2.5 cc. The V12Gy was higher with MBM for lesions > 0.4 cc or SI < 0.84 and exceeded 10 cc for targets > 5 cc against 6.5 cc with GP. The presence of OAR close to the PTV had no impact on the dose fall off values. The dose fall-off was higher for volumes < 3.8 cc with GP which had the sharpest dose fall-off in the infero-superior direction up to 30%/mm. The mean beam-on time was 94 min with GP against 13 min with MBM. Conclusions The dose fall-off and the V12Gy were more relevant indicators than the GI for the low dose spillage assessment. Both evaluated techniques have comparable plan qualities with a slightly improved selectivity with MBM for smaller lesions but with a healthy tissues sparing slightly favorable to GP at the expense of a considerably longer irradiation time. However, a higher healthy tissue exposure must be considered for large volumes in MBM plans.
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Affiliation(s)
- Michel Chea
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France.
| | - Karen Fezzani
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Julian Jacob
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Marguerite Cuttat
- Neurosurgery Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, Paris, France
| | - Mathilde Croisé
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Jean-Marc Simon
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Loïc Feuvret
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Charles-Ambroise Valery
- Neurosurgery Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, Paris, France
| | - Philippe Maingon
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
| | - Mohamed-Amine Benadjaoud
- PSE-SANTE/SERAMED, Radiation Protection and Nuclear Safety Institute, Fontenay aux Roses, France
| | - Catherine Jenny
- Radiation Oncology Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, 47-83 Boulevard de l'Hôpital, 75651, Paris Cedex 13, France
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Parikh NR, Kundu P, Levin-Epstein R, Chang EM, Agazaryan N, Hegde JV, Steinberg ML, Tenn SE, Kaprealian TB. Time-Driven Activity-Based Costing Comparison of Stereotactic Radiosurgery to Multiple Brain Lesions Using Single-Isocenter Versus Multiple-Isocenter Technique. Int J Radiat Oncol Biol Phys 2020; 108:999-1007. [PMID: 32603774 DOI: 10.1016/j.ijrobp.2020.06.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 04/30/2020] [Accepted: 06/22/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE Stereotactic radiosurgery (SRS) historically has been used to treat multiple brain lesions using a multiple-isocenter technique-frequently associated with significant complexity in treatment planning and long treatment times. Recently, given innovations in planning algorithms, patients with multiple brain lesions may now be treated with a single-isocenter technique using fewer total arcs and less time spent during image guidance (though with stricter image guided radiation therapy tolerances). This study used time-driven activity-based costing to determine the difference in cost to a provider for delivering SRS to multiple brain lesions using single-isocenter versus multiple-isocenter techniques. METHODS AND MATERIALS Process maps, consisting of discrete steps, were created for each phase of the SRS care cycle and were based on interviews with department personnel. Actual treatment times (including image guidance) were extracted from treatment record and verify software. Additional sources of data to determine costs included salary/benefit data of personnel and average list price/maintenance costs for equipment. RESULTS Data were collected for 22 patients who underwent single-isocenter SRS (mean lesions treated, 5.2; mean treatment time, 30.2 minutes) and 51 patients who underwent multiple-isocenter SRS (mean lesions treated, 4.4; mean treatment time, 75.2 minutes). Treatment time for multiple-isocenter SRS varied substantially with increasing number of lesions (11.8 minutes/lesion; P < .001), but to a much lesser degree in single-isocenter SRS (1.8 minutes/lesion; P = .029). The resulting cost savings from single-isocenter SRS based on number of lesions treated ranged from $296 to $3878 for 2 to 10 lesions treated. The 2-mm planning treatment volume margin used with single-isocenter SRS resulted in a mean 43% increase of total volume treated compared with a 1-mm planning treatment volume expansion. CONCLUSIONS In a comparison of time-driven activity-based costing assessment of single-isocenter versus multiple-isocenter SRS for multiple brain lesions, single-isocenter SRS appears to save time and resources for as few as 2 lesions, with incremental benefits for additional lesions treated.
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Affiliation(s)
- Neil R Parikh
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Palak Kundu
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Rebecca Levin-Epstein
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Eric M Chang
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Nzhde Agazaryan
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - John V Hegde
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Michael L Steinberg
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Stephen E Tenn
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California
| | - Tania B Kaprealian
- Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California.
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Radiosurgery treatment planning using conformal arc informed volumetric modulated arc therapy. Med Dosim 2020; 46:3-12. [PMID: 32807612 DOI: 10.1016/j.meddos.2020.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/14/2020] [Accepted: 06/04/2020] [Indexed: 11/23/2022]
Abstract
Linac based radiosurgery to multiple metastases is commonly planned with volumetric modulated arc therapy (VMAT) as it effectively achieves high conformality to complex target arrangements. However, as the number of targets increases, VMAT can struggle to block between targets, which can lead to highly modulated and/or nonconformal multi-leaf collimator (MLC) trajectories that unnecessarily irradiation of healthy tissue. In this study we introduce, describe, and evaluate a treatment planning technique called Conformal Arc Informed VMAT (CAVMAT), which aims to reduce the dose to healthy tissue while generating highly conformal treatment plans. CAVMAT is a hybrid technique which combines the conformal MLC trajectories of dynamic conformal arcs with the MLC modulation and versatility of inverse optimization. CAVMAT has 3 main steps. First, targets are assigned to subgroups to maximize MLC blocking between targets. Second, arc weights are optimized to achieve the desired target dose, while minimizing MU variation between arcs. Third, the optimized conformal arc plan serves as the starting point for limited inverse optimization to improve dose conformity to each target. Twenty multifocal VMAT cases were replanned with CAVMAT with 20Gy applied to each target. The total volume receiving 2.5Gy[cm3], 6Gy[cm3], 12Gy[cm3], and 16Gy[cm3], conformity index, treatment delivery time, and the total MU were used to compare the VMAT and CAVMAT plans. In addition, CAVMAT was compared to a broad range of planning strategies from various institutions (108 linear accelerator based plans, 14 plans using other modalities) for a 5-target case utilized in a recent plan challenge. For the linear accelerator-based plans, a plan complexity metric based on aperture opening area and perimeter, total monitor units (MU), and MU for a given aperture opening was utilized in the plan challenge scoring algorithm to compare the submitted plans to CAVMAT. After re-planning the 20 VMAT cases, CAVMAT reduced the average V2.5Gy[cm3] by 25.25 ± 19.23%, V6Gy[cm3] by 13.68 ± 18.97%, V12Gy[cm3] by 11.40 ± 19.44%, and V16Gy[cm3] by 6.38 ± 19.11%. CAVMAT improved conformity by 3.81 ± 7.57%, while maintaining comparable target dose. MU for the CAVMAT plans increased by 24.35 ± 24.66%, leading to an increased treatment time of 2 minutes. For the plan challenge case, CAVMAT was 1 of 12 linac based plans that met all plan challenge scoring criteria. Compared to the average submitted VMAT plan, CAVMAT increased the V10%Gy[%] of healthy tissue (Brain-PTV) by roughly 3.42%, but in doing so was able to reduce the V25%Gy[%] by roughly 3.73%, while also reducing V50%Gy[%], V75%Gy[%], and V100%Gy[%]. The CAVMAT technique successfully eliminated insufficient MLC blocking between targets prior to the inverse optimization, leading to less complex treatment plans and improved tissue sparing. Tissue sparing, improved conformity, and decreased plan complexity at the cost of slight increase in treatment delivery time indicates CAVMAT to be a promising method to treat brain metastases.
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9
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Capaldi DPI, Skinner LB, Dubrowski P, Yu AS. An integrated quality assurance phantom for frameless single-isocenter multitarget stereotactic radiosurgery. ACTA ACUST UNITED AC 2020; 65:115006. [DOI: 10.1088/1361-6560/ab8534] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Pant K, Umeh C, Oldham M, Floyd S, Giles W, Adamson J. Comprehensive radiation and imaging isocenter verification using NIPAM kV-CBCT dosimetry. Med Phys 2020; 47:927-936. [PMID: 31899806 DOI: 10.1002/mp.14008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To develop and demonstrate a comprehensive method to directly measure radiation isocenter uncertainty and coincidence with the cone-beam computed tomography (kV-CBCT) imaging coordinate system that can be carried out within a typical quality assurance (QA) time slot. METHODS An N-isopropylacrylamide (NIPAM) three-dimensional (3D) dosimeter for which dose is observed as increased electron density in kV-CBCT is irradiated at eight couch/gantry combinations which enter the dosimeter at unique orientations. One to three CBCTs are immediately acquired, radiation profile is detected per beam, and displacement from imaging isocenter is quantified. We performed this test using a 5 mm diameter MLC field, and 7.5 and 4 mm diameter cones, delivering approximately 16 Gy per beam. CBCT settings were 1035-4050 mAs, 80-125 kVs, smooth filter, 1 mm slice thickness. The two-dimensional (2D) displacement of each beam from the imaging isocenter was measured within the planning system, and Matlab code developed in house was used to quantify relevant parameters based on the actual beam geometry. Detectability of the dose profile in the CBCT was quantified as the contrast-to-noise ratio (CNR) of the irradiated high-dose regions relative to the surrounding background signal. Our results were compared to results determined by the traditional Winston-Lutz test, film-based "star shots," and the vendor provided machine performance check (MPC). The ability to detect alignment errors was demonstrated by repeating the test after applying a 0.5 mm shift to the MLCs in the direction of leaf travel. In addition to radiation isocenter and coincidence with CBCT origin, the analysis also calculated the actual gantry and couch angles per beam. RESULTS Setup, MV irradiation, and CBCT readout were carried out within 38 min. After subtracting the background signal from the pre-CBCT, the CNR of the dosimeter signal from the irradiation with the MLCs (125 kVp, 1035 mAs, n = 3), 7.5 mm cone (125 kVp, 1035 mAs, n = 3), and 4 mm cone (80 kVp, 4050 mAs, n = 1) was 5.4, 5.9, and 2.9, respectively. The minimum radius that encompassed all beams calculated using the automated analysis was 0.38, 0.48, and 0.44 mm for the MLCs, 7.5 mm cone, and 4 mm cone, respectively. When determined manually, these values were slightly decreased at 0.28, 0.41, and 0.40 mm. For comparison, traditional Winston-Lutz test with MLCs and MPC measured the 3D isocenter radius to be 0.24 mm. Lastly, when a 0.5 mm shift to the MLCs was applied, the smallest radius that intersected all beams increased from 0.38 to 0.90 mm. The mean difference from expected value for gantry angle was 0.19 ± 0.29°, 0.17 ± 0.23°, and 0.12 ± 0.14° for the MLCs, 7.5 mm cone, and 4 mm cone, respectively. The mean difference from expected for couch angle was -0.07 ± 0.28°, -0.08 ± 0.66°, and 0.04 ± 0.25°. CONCLUSIONS This work demonstrated the feasibility of a comprehensive isocenter verification using a NIPAM dosimeter with sub-mm accuracy which incorporates evaluation of coincidence with imaging coordinate system, and may be applicable to all SRS cones as well as MLCs.
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Affiliation(s)
- Kiran Pant
- Medical Physics Graduate Program, Duke University, Durham, NC, USA
| | - Chibuike Umeh
- Medical Physics Graduate Program, Duke Kunshan University, Suzhou, China.,Department of Physics and Astronomy, University of Nigeria Nsukka, Nsukka, Nigeria
| | - Mark Oldham
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - Scott Floyd
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - Will Giles
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
| | - Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, NC, USA
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Bonfantini F, Giandini T, Meroni S, Cavallo A, Stucchi C, Carrara M, Mongioj V, Veronese I, Pignoli E. Application of failure mode and effects analysis to optimization of linac quality controls protocol. Med Phys 2019; 46:2541-2555. [DOI: 10.1002/mp.13538] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2018] [Revised: 01/31/2019] [Accepted: 03/27/2019] [Indexed: 11/12/2022] Open
Affiliation(s)
- Francesca Bonfantini
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Tommaso Giandini
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Silvia Meroni
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Anna Cavallo
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Claudio Stucchi
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Mauro Carrara
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Valeria Mongioj
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
| | - Ivan Veronese
- Physics Department Università degli Studi di Milano and Istituto Nazionale di Fisica Nucleare Sezione di Milano Via Giovanni Celoria 16 20133 Milan Italy
| | - Emanuele Pignoli
- Medical Physics Unit Fondazione IRCCS Istituto Nazionale dei Tumori via Venezian 1 20133 MilanItaly
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Adamson J, Carroll J, Trager M, Yoon SW, Kodra J, Maynard E, Hilts M, Oldham M, Jirasek A. Delivered Dose Distribution Visualized Directly With Onboard kV-CBCT: Proof of Principle. Int J Radiat Oncol Biol Phys 2018; 103:1271-1279. [PMID: 30578910 DOI: 10.1016/j.ijrobp.2018.12.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/06/2018] [Accepted: 12/11/2018] [Indexed: 11/15/2022]
Abstract
PURPOSE To demonstrate proof of principle of visualizing delivered 3-dimensional (3D) dose distribution using kilovoltage (kv) cone beam computed tomography (CBCT) mounted onboard a linear accelerator. We apply this technique as a unique end-to-end verification of multifocal radiosurgery where the coincidence of radiation and imaging systems is quantified comprehensively at all targets. METHODS AND MATERIALS Dosimeters (9.5-cm diameter N-isopropylacrylamide) were prepared according to standard procedures at one facility and shipped to a second (remote) facility for irradiation. A 4-arc volumetric modulated arc therapy (VMAT) multifocal radiosurgery plan was prepared to deliver 20 Gy with 6-MV photons to 6 targets (1-cm diameter). A dosimeter was aligned via CBCT and irradiated, followed by 3 CBCT scans acquired immediately, with total time between pre-CBCT and final CBCT <30 minutes. Image processing included background subtraction and low-pass filters. A dose-volume structure was created per target with the same volume as the planned prescription dose volume, and their spatial agreement was quantified using volume centroid and the Jaccard index. For comparison, 5 diagnostic computed tomography (CT) scans were also acquired after >24 hours with the same spatial analysis applied; comparison with planned doses after absolute dose calibration also was conducted. RESULTS Regions of high dose were clearly visualized in the average CBCT with a contrast-to-noise ratio of 1.7 ± 0.7, which increased to 5.8 ± 0.5 after image processing, and 11.9 ± 3.7 for average diagnostic CT. Centroids of prescription isodose volumes agreed with the root mean square difference of 1.1 mm (range, 0.8-1.7 mm) for CBCT and 0.7 mm (0.4-0.8 mm) for diagnostic CT. The dose was proportional to density above 10 to 12 Gy with a 3D gamma pass rate of 94.0% and 99.5% using 5% for 1-mm and 3% for 2-mm criteria, respectively (threshold = 15 Gy, using global dose criteria). CONCLUSIONS This work demonstrates for the first time the potential to visualize in 3D delivered dose using onboard kV-CBCT (0.5 × 0.5 × 1 mm3 voxel size) immediately after irradiation with a sufficient contrast-to-noise ratio to measure radiation and imaging system coincidence to within 2 mm.
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Affiliation(s)
- Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
| | - Jaclyn Carroll
- Medical Physics Graduate Program, Duke University, Durham, North Carolina
| | - Michael Trager
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - Suk Whan Yoon
- Medical Physics Graduate Program, Duke University, Durham, North Carolina
| | - Jacob Kodra
- Medical Physics Graduate Program, Duke University, Durham, North Carolina
| | - Evan Maynard
- Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada
| | - Michelle Hilts
- Medical Physics, BC Cancer, Kelowna, British Columbia, Canada; Department of Physics, Irving K. Barber School of Arts and Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada
| | - Mark Oldham
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
| | - Andrew Jirasek
- Department of Physics, Irving K. Barber School of Arts and Sciences, University of British Columbia-Okanagan Campus, Kelowna, British Columbia, Canada
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Faught AM, Trager M, Yin FF, Kirkpatrick J, Adamson J. Re-examining TG-142 recommendations in light of modern techniques for linear accelerator based radiosurgery. Med Phys 2017; 43:5437. [PMID: 27782700 DOI: 10.1118/1.4962471] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The recent development of multifocal stereotactic radiosurgery (SRS) using a single isocenter volumetric modulated arc theory (VMAT) technique warrants a re-examination of the quality assurance (QA) tolerances for routine mechanical QA recommended by the American Association of Physicists in Medicine Task Group Report Number 142. Multifocal SRS can result in targets with small volumes being at a large off-axis distance from the treatment isocenter. Consequently, angular errors in the collimator, patient support assembly (PSA), or gantry could have an increased impact on target coverage. METHODS The authors performed a retrospective analysis of dose deviations caused by systematic errors in PSA, collimator, and gantry angle at the tolerance level for routine linear accelerator QA as recommended by TG-142. Dosimetric deviations from multifocal SRS plans (N = 10) were compared to traditional single target SRS using dynamic conformal arcs (N = 10). The chief dosimetric quantities used in determining clinical impact were V100% and D99% of the individual planning target volumes and V12Gy of the healthy brain. RESULTS Induced errors at tolerance levels showed the greatest change in multifocal SRS target coverage for collimator rotations (±1.0°) with the average changes to V100% and D99% being 5% and 6%, respectively, with maximum changes of 33% and 20%. A reduction in the induced error to half the TG-142 tolerance (±0.5°) demonstrated similar changes in coverage loss to traditional single target SRS assessed at the recommended tolerance level. The observed change in coverage for multifocal SRS was reduced for gantry errors (±1.0°) at 2% and 4.5% for V100% and D99%, respectively, with maximum changes of 18% and 12%. Minimal change in coverage was noted for errors in PSA rotation. CONCLUSIONS This study indicates that institutions utilizing a single isocenter VMAT technique for multifocal disease should pay careful attention to the angular mechanical tolerances in designing a robust and complete QA program.
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Affiliation(s)
- Austin M Faught
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - Michael Trager
- Medical Physics Graduate Program, Duke University, Durham, North Carolina 27710
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - John Kirkpatrick
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
| | - Justus Adamson
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27710
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O'Daniel JC, Yin FF. Quantitative Approach to Failure Mode and Effect Analysis for Linear Accelerator Quality Assurance. Int J Radiat Oncol Biol Phys 2017; 98:56-62. [PMID: 28587053 DOI: 10.1016/j.ijrobp.2017.01.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/21/2016] [Accepted: 01/13/2017] [Indexed: 11/20/2022]
Abstract
PURPOSE To determine clinic-specific linear accelerator quality assurance (QA) TG-142 test frequencies, to maximize physicist time efficiency and patient treatment quality. METHODS AND MATERIALS A novel quantitative approach to failure mode and effect analysis is proposed. Nine linear accelerator-years of QA records provided data on failure occurrence rates. The severity of test failure was modeled by introducing corresponding errors into head and neck intensity modulated radiation therapy treatment plans. The relative risk of daily linear accelerator QA was calculated as a function of frequency of test performance. RESULTS Although the failure severity was greatest for daily imaging QA (imaging vs treatment isocenter and imaging positioning/repositioning), the failure occurrence rate was greatest for output and laser testing. The composite ranking results suggest that performing output and lasers tests daily, imaging versus treatment isocenter and imaging positioning/repositioning tests weekly, and optical distance indicator and jaws versus light field tests biweekly would be acceptable for non-stereotactic radiosurgery/stereotactic body radiation therapy linear accelerators. CONCLUSIONS Failure mode and effect analysis is a useful tool to determine the relative importance of QA tests from TG-142. Because there are practical time limitations on how many QA tests can be performed, this analysis highlights which tests are the most important and suggests the frequency of testing based on each test's risk priority number.
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Affiliation(s)
- Jennifer C O'Daniel
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina.
| | - Fang-Fang Yin
- Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina
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