Evaluation of Auto-Contouring and Dose Distributions for Online Adaptive Radiation Therapy of Patients With Locally Advanced Lung Cancers

Mao, Weihua; Riess, Jeff; Kim, Joshua; Vance, Sean; Chetty, Indrin J.; Movsas, Benjamin; Kretzler, Annette

doi:10.1016/j.prro.2021.12.017

Cited by 38 publications

(27 citation statements)

References 30 publications

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“…This is primarily due to the increased optimization and calculation time needed for VMAT techniques with adaptive deliveries. Other groups have found enhanced plan quality with IMRT as compared to VMAT [33][34][35]. 6 and Figure 6 show the breakdown of treatment times by task for all of the analyzed fractions, separated into adaptive and non-adaptive treatments.…”

Section: Patient Demographics and Site Breakdownmentioning

confidence: 99%

A roadmap for implementation of kV-CBCT online adaptive radiation therapy and initial first year experiences

Stanley

Harms

Pogue

et al. 2022

Preprint

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Purpose: Online Adaptive Radiation Therapy(oART) follows a different treatment paradigm than conventional radiotherapy and, because of this, the resources, implementation, and workflows needed are unique. The purpose of this report is to outline our institution's experience establishing, organizing, and implementing an oART program using the Ethos therapy system. Methods: We include resources used; operational models utilized, program creation timelines, and our institutional experiences with implementation and operation of an oART program. Additionally, we provide a detailed summary of our first year's clinical experience where we delivered over 1000 daily adaptive fractions. For all treatments, the different stages of online adaption, primary patient set-up, initial kV-CBCT acquisition, contouring review and edit of influencer structures, target review and edits, plan evaluation and selection, Mobius3D 2nd check and adaptive QA, 2nd kV-CBCT for positional verification, treatment delivery, and patient leaving the room, were analyzed. Results: We retrospectively analyzed data from ninety-seven patients treated from August 2021-August 2022. 1677 individual fractions were treated and analyzed, 632(38%) were non-adaptive and 1045(62%) were adaptive. 74 of the 97 patients (76%) were treated with standard fractionation and 23 (24%) received stereotactic treatments. For the adaptive treatments, the generated adaptive plan was selected in 92% of treatments. On average(±std), adaptive sessions took 34.52±11.42 minutes from start to finish. The entire adaptive process (from start of contour generation to verification CBCT), performed by the physicist (and physician on select days), was 19.84±8.21 minutes. Conclusion: We present our institution's experience establishing, organizing, and implementing an oART program using the Ethos therapy system. It took us 12 months from project inception to treatment of our first patient and 12 months to treat 1000 adaptive fractions. Retrospective analysis of delivered fractions showed that average overall treatment time was approximately 35 minutes and average time for the adaptive component of treatment was approximately 20 minutes.

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Section: Patient Demographics and Site Breakdownmentioning

confidence: 99%

A roadmap for implementation of kV-CBCT online adaptive radiation therapy and initial first year experiences

Stanley

Harms

Pogue

et al. 2022

Preprint

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“…It should also be mentioned that the OAR dose being spared would be greater were the 6Gy x 5 hypofractionated scheme converted to 2Gy equivalent fractions. Furthermore, the Ethos platform allows for RT plan adaption based on daily cone beam CT (CBCT) anatomy (38,39), which could allow for further reduced doses due to daily re-optimization. Ethos plans were slightly, but consistently, less conformal than Eclipse plans.…”

Section: Discussionmentioning

confidence: 99%

Leveraging intelligent optimization for automated, cardiac-sparing accelerated partial breast treatment planning

et al. 2023

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BackgroundAccelerated partial breast irradiation (APBI) yields similar rates of recurrence and cosmetic outcomes as compared to whole breast radiation therapy (RT) when patients and treatment techniques are appropriately selected. APBI combined with stereotactic body radiation therapy (SBRT) is a promising technique for precisely delivering high levels of radiation while avoiding uninvolved breast tissue. Here we investigate the feasibility of automatically generating high quality APBI plans in the Ethos adaptive workspace with a specific emphasis on sparing the heart.MethodsNine patients (10 target volumes) were utilized to iteratively tune an Ethos APBI planning template for automatic plan generation. Twenty patients previously treated on a TrueBeam Edge accelerator were then automatically replanned using this template without manual intervention or reoptimization. The unbiased validation cohort Ethos plans were benchmarked via adherence to planning objectives, a comparison of DVH and quality indices against the clinical Edge plans, and qualitative reviews by two board-certified radiation oncologists.Results85% (17/20) of automated validation cohort plans met all planning objectives; three plans did not achieve the contralateral lung V1.5Gy objective, but all other objectives were achieved. Compared to the Eclipse generated plans, the proposed Ethos template generated plans with greater evaluation planning target volume (PTV_Eval) V100% coverage (p = 0.01), significantly decreased heart V1.5Gy (p< 0.001), and increased contralateral breast V5Gy, skin D0.01cc, and RTOG conformity index (p = 0.03, p = 0.03, and p = 0.01, respectively). However, only the reduction in heart dose was significant after correcting for multiple testing. Physicist-selected plans were deemed clinically acceptable without modification for 75% and 90% of plans by physicians A and B, respectively. Physicians A and B scored at least one automatically generated plan as clinically acceptable for 100% and 95% of planning intents, respectively.ConclusionsStandard left- and right-sided planning templates automatically generated APBI plans of comparable quality to manually generated plans treated on a stereotactic linear accelerator, with a significant reduction in heart dose compared to Eclipse generated plans. The methods presented in this work elucidate an approach for generating automated, cardiac-sparing APBI treatment plans for daily adaptive RT with high efficiency.

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“…However, a separate CBCT to sCT conversion algorithm might need to be trained for different CBCT scanners [ 22 ]. Alternatively, some of the new linear accelerators, such as the Ethos (Varian Medical Systems, Palo Alto, CA), are already equipped for online ART [ 54 ].…”

Section: Discussionmentioning

confidence: 99%

Dosimetric benefits of adaptive radiation therapy for patients with stage III non-small cell lung cancer

et al. 2023

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Background Daily adaptive radiation therapy (ART) of patients with non-small cell lung cancer (NSCLC) lowers organs at risk exposure while maintaining the planning target volume (PTV) coverage. Thus, ART allows an isotoxic approach with increased doses to the PTV that could improve local tumor control. Herein we evaluate daily online ART strategies regarding their impact on relevant dose-volume metrics. Methods Daily cone-beam CTs (1 × n = 28, 1 × n = 29, 11 × n = 30) of 13 stage III NSCLC patients were converted into synthetic CTs (sCTs). Treatment plans (TPs) were created retrospectively on the first-fraction sCTs (sCT1) and subsequently transferred unaltered to the sCTs of the remaining fractions of each patient (sCT2−n) (IGRT scenario). Two additional TPs were generated on sCT2−n: one minimizing the lung-dose while preserving the D95%(PTV) (isoeffective scenario), the other escalating the D95%(PTV) with a constant V20Gy(lungipsilateral) (isotoxic scenario). Results Compared to the original TPs predicted dose, the median D95%(PTV) in the IGRT scenario decreased by 1.6 Gy ± 4.2 Gy while the V20Gy(lungipsilateral) increased in median by 1.1% ± 4.4%. The isoeffective scenario preserved the PTV coverage and reduced the median V20Gy(lungipsilateral) by 3.1% ± 3.6%. Furthermore, the median V5%(heart) decreased by 2.9% ± 6.4%. With an isotoxic prescription, a median dose-escalation to the gross target volume of 10.0 Gy ± 8.1 Gy without increasing the V20Gy(lungipsilateral) and V5%(heart) was feasible. Conclusions We demonstrated that even without reducing safety margins, ART can reduce lung-doses, while still reaching adequate target coverage or escalate target doses without increasing ipsilateral lung exposure. Clinical benefits by means of toxicity and local control of both strategies should be evaluated in prospective clinical trials.

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Evaluation of Auto-Contouring and Dose Distributions for Online Adaptive Radiation Therapy of Patients With Locally Advanced Lung Cancers

Cited by 38 publications

References 30 publications

A roadmap for implementation of kV-CBCT online adaptive radiation therapy and initial first year experiences

A roadmap for implementation of kV-CBCT online adaptive radiation therapy and initial first year experiences

Leveraging intelligent optimization for automated, cardiac-sparing accelerated partial breast treatment planning

Dosimetric benefits of adaptive radiation therapy for patients with stage III non-small cell lung cancer

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