The Stanford Volumetric Modulated Arc Therapy Total Body Irradiation Technique

Kovalchuk, Nataliya; Simiele, Eric; Skinner, Lawrie; Yang, Yong; Howell, Nicole; Lewis, J. K.; Hui, Caressa; Blomain, Erik; Hoppe, Richard T.; Hiniker, Susan M.

doi:10.1016/j.prro.2021.12.007

Cited by 21 publications

(15 citation statements)

References 25 publications

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“…Multiple application programming interface (API) scripts were developed within version 15.6 of the Varian treatment planning system Eclipse Scripting API (ESAPI) to facilitate auto-planning. The framework for these scripts were derived from the results of our previously published works with VMAT TBI auto-planning ( 12 , 13 ). The process was broken into two parts: preparation and optimization.…”

Section: Methodsmentioning

confidence: 99%

Automated contouring, treatment planning, and quality assurance for VMAT craniospinal irradiation (VMAT-CSI)

Simiele,

Romero,

Wang

et al. 2024

Front. Oncol.

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PurposeCreate a comprehensive automated solution for pediatric and adult VMAT-CSI including contouring, planning, and plan check to reduce planning time and improve plan quality.MethodsSeventy-seven previously treated CSI patients (age, 2-67 years) were used for creation of an auto-contouring model to segment 25 organs at risk (OARs). The auto-contoured OARs were evaluated using the Dice Similarity Coefficient (DSC), 95% Hausdorff Distance (HD95), and a qualitative ranking by one physician and one physicist (scale: 1-acceptable, 2-minor edits, 3-major edits). The auto-planning script was developed using the Varian Eclipse Scripting API and tested with 20 patients previously treated with either low-dose VMAT-CSI (12 Gy) or high-dose VMAT-CSI (36 Gy + 18 Gy boost). Clinically relevant metrics, planning time, and blinded physician review were used to evaluate significance of differences between the auto and manual plans. Finally, the plan preparation for treatment and plan check processes were automated to improve efficiency and safety of VMAT-CSI.ResultsThe auto-contours achieved an average DSC of 0.71 ± 0.15, HD95 of 4.81 ± 4.68, and reviewers’ ranking of 1.22 ± 0.39, indicating close to “acceptable-as-is” contours. Compared to the manual CSI plans, the auto-plans for both dose regimens achieved statistically significant reductions in body V50% and Dmean for parotids, submandibular, and thyroid glands. The variance in the dosimetric parameters decreased for the auto-plans as compared to the manual plans indicating better plan consistency. From the blinded review, the auto-plans were marked as equivalent or superior to the manual-plans 88.3% of the time. The required time for the auto-contouring and planning was consistently between 1-2 hours compared to an estimated 5-6 hours for manual contouring and planning.ConclusionsReductions in contouring and planning time without sacrificing plan quality were obtained using the developed auto-planning process. The auto-planning scripts and documentation will be made freely available to other institutions and clinics.

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Section: Methodsmentioning

confidence: 99%

Automated contouring, treatment planning, and quality assurance for VMAT craniospinal irradiation (VMAT-CSI)

Simiele,

Romero,

Wang

et al. 2024

Front. Oncol.

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“…Other challenges presented in conventional TBI include the reproducibility of patient set‐up, including positioning of lung and kidney shields for upright and lateral set‐ups and difficulties for sick patients to stand for long periods of time (40–50 min), which increase the occurrence of inaccuracies in patient set‐up 8,9 . Recently, multi‐isocentric volumetric‐modulated arc therapy (VMAT) technique have been developed for total body irradiation to improve patient comfort, dose uniformity, and vulnerable tissue protection 10–21 . VMAT‐TBI also allows the use of image guidance to improve the accuracy of patient set‐up.…”

Section: Introductionmentioning

confidence: 99%

“…8,9 Recently, multi-isocentric volumetric-modulated arc therapy (VMAT) technique have been developed for total body irradiation to improve patient comfort, dose uniformity, and vulnerable tissue protection. [10][11][12][13][14][15][16][17][18][19][20][21] VMAT-TBI also allows the use of image guidance to improve the accuracy of patient set-up. However, a major drawback that may limit application of VMAT-TBI is that the process is time consuming and complicated.…”

Section: Introductionmentioning

confidence: 99%

Implementing failure mode and effect analysis to improve the safety of volumetric modulated arc therapy for total body irradiation

Gray,

Antolak,

Ahmed

et al. 2023

Medical Physics

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Volumetric-modulated arc therapy for total body irradiation (VMAT-TBI) is a novel radiotherapy technique that has been implemented at our institution. The purpose of this work is to investigate possible failure modes (FMs) in the treatment process and to develop a quality control (QC) program for VMAT-TBI following TG-100 guidelines. Methods: We formed a multidisciplinary team to map out the complete treatment process of VMAT-TBI following the AAPM TG-100 guidelines. This process map gives a visual representation of the VMAT-TBI workflow from the CT simulation, image processing, contouring, treatment planning, to treatment delivery. From the process map, potential FMs were identified. The occurrence (O), detectability (D), and severity of impact (S) of each FM were assigned according to scoring criteria (1-10) by the multidisciplinary team. A risk priority number (RPN) was calculated from average O, S, and D of each FM (RPN = O x S x D). High risk FMs were identified as 20% of the FMs having the highest RPN scores. After the FMEA analysis, fault-tree analysis (FTA) was performed for each major step of the treatment process to determine the effects of potential failures to the treatment outcome.Effective QC methods were identified to prevent the high risk failures and to improve the safety of the VMAT-TBI program. Results: We identified a total of 55 sub-processes and 128 FMs from the VMAT-TBI workflow. The top five high-risk FMs were: (1) Prescription and/or OAR constraints changed during planning and not communicated to the planner, (2) Patient moves or breathes too heavily during the upper body CT scan (3) Patient moves during the lower body CT scan,(4) Treatment planning system not calculating total body DVH metrics correctly for TBI, (5) Improper optimization criteria used or not sufficient optimization, resulting in suboptimal dose coverage, OAR sparing or excessive hotspots during treatment planning. Two FMs have average severity scores ≥8: Incorrect PTV subdivision/isocenter placement and Prescription and/or OAR constraints changed during planning and not communicated to the planner. Quality assurance and QC interventions including staff training, standard operating procedures, and quality checklists were implemented based on the FMEA and FTA.

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“…However, these treatment techniques require expertise and special equipment, which has limited their accessibility, and relatively scarce data regarding dosimetric comparisons have been reported. We have developed the Stanford auto-planned VMAT-TBI technique, 13,16,17 and shared the auto-planning scripts with the public to make VMAT-TBI more widespread (https://github.com/esimiele/VMAT-TBI). Our technique was also included as a basis for VMAT-TBI methodology among 2D and tomotherapy TBI techniques on COG ASCT2031 trial.…”

Section: Introductionmentioning

confidence: 99%

Improved organ sparing using auto‐planned Stanford volumetric modulated arc therapy for total body irradiation technique

Ngo

Blomain

Simiele

et al. 2023

Pediatric Blood & Cancer

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Purpose/objectivesTo evaluate dosimetric differences between auto‐planned volumetric modulated arc therapy (VMAT) total body irradiation (TBI) technique and two‐dimensional radiotherapy using anterior‐posterial/posterio‐anterial beams (2D AP/PA) TBI technique.MethodsTen pediatric patients treated with VMAT‐TBI on Varian c‐arm linac were included in this study. VMAT‐TBI plans were generated using our in‐house developed and publicly shared auto‐planning scripts. For each VMAT‐TBI plan, a 2D AP/PA plan was created replicating the institution's clinical setup with the patient positioned at extended source to skin distance (SSD) with a compensator to account for differences in patient thickness, 50% transmission daily lung blocks, and electron chest wall boosts prescribed to 50% of the photon prescription. Clinically relevant metrics were analyzed and compared between the VMAT and 2D plans.ResultsAll VMAT‐TBI plans achieved planned target volume (PTV) D90% ≥ 100% of prescription. VMAT‐TBI PTV D90% significantly increased (7.1% ± 2.9%, p < .001) compared to the 2D technique, whereas no differences were observed in global Dmax (p < .2) and PTV V110% (p < .4). Compared to the 2D plans, significant decreases in the Dmean to the lungs (−25.6% ± 11.5%, p < .001) and lungs‐1 cm (−34.1% ± 10.1%, p < .001) were observed with the VMAT plans. The VMAT technique also enabled decrease of dose to other organs: kidneys Dmean (−32.5% ± 5.0%, p < .001) and lenses Dmax (−5.3% ± 8.1%, p = .03); and in addition, for 2 Gy prescription: testes/ovaries Dmean (−41.5% ± 11.5%, p < .001), brain Dmean (−22.6% ± 5.4%, p = .002), and thyroid Dmean (−18.2% ± 16.0%, p = .03).ConclusionsSuperior lung sparing with improved target coverage and similar global Dmax were observed with the VMAT plans as compared to 2D plans. In addition, VMAT‐TBI plans provided greater dose reductions in gonads, kidneys, brain, thyroid, and lenses.

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The Stanford Volumetric Modulated Arc Therapy Total Body Irradiation Technique

Cited by 21 publications

References 25 publications

Automated contouring, treatment planning, and quality assurance for VMAT craniospinal irradiation (VMAT-CSI)

Automated contouring, treatment planning, and quality assurance for VMAT craniospinal irradiation (VMAT-CSI)

Implementing failure mode and effect analysis to improve the safety of volumetric modulated arc therapy for total body irradiation

Improved organ sparing using auto‐planned Stanford volumetric modulated arc therapy for total body irradiation technique

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