Evaluation of an automated template-based treatment planning system for radiotherapy of anal, rectal and prostate cancer

et al. 2022

Preprint

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.

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Patient Breakdownmentioning

confidence: 99%

See 1 more Smart Citation

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

Stanley

et al. 2022

Preprint

“…These results are in good agreement with Calmels et al, who observed that, for most planning objectives, the Ethos TPS generates plans with similar or better target coverage and OAR sparing compared to manually generated Eclipse VMAT plans for anal, rectal, and prostate cancers. 19 Thus, even though their study focused on pelvic sites, it indicates that one can expect an improvement in some, but not all, objective metrics when transitioning from manual Eclipse planning to automated Ethos planning. 3) should be utilized to elucidate TPS dose difference continuously as a function of target/OAR volume when necessary.…”

Section: Discussionmentioning

confidence: 98%

“…15 Other studies have demonstrated that Ethos daily adaptive prostate and abdominal SBRT plans generally result in Validating automated Ethos radiotherapy plans higher target coverage and a reduced risk of exceeding clinical OAR thresholds compared to scheduled plans, and that the Ethos intensity modulated radiation therapy (IMRT) optimizer generates similar or better quality pelvis RT plans compared to manually generated Eclipse volumetric modulated arc therapy (VMAT) techniques. [16][17][18][19] However, there has been limited investigation of Ethos thoracic RT plan quality. As the Ethos system introduces a new TPS, and the TPS drives RT plan generation, a quantitative understanding of the differences in dose distributions between conventional linear accelerator-based treatments and Ethos TPS treatments is needed.…”

Section: Introductionmentioning

confidence: 99%

Design and validation of an automated radiation therapy treatment planning approach for locally advanced lung cancer

Cárdenas

et al. 2022

Preprint

Purpose: Radiation therapy planning for locally-advanced non-small cell lung cancer (NSCLC) is challenging due to the balancing of target coverage and organs-at-risk (OAR) sparing. Using the Varian Ethos Treatment Planning System (TPS), we developed a methodology to automatically generate efficient, high-quality treatment plans for locally-advanced lung cancer patients. Methods and Materials: Fifty patients previously treated with Eclipse-generated plans for inoperable Stage IIIA-IIIC NSCLC were included in this Institutional Review Board (IRB)-approved retrospective study. Fifteen patients were used to iteratively optimize an Ethos TPS planning template, and the remaining thirty-five patients had plans automatically generated without manual intervention using the created template. Ethos and Eclipse plan quality was then assessed using 1) standard dose volume histogram (DVH) metrics, 2) adherence to clinical trial objectives, and 3) radiation oncologist qualitative review. Results: Ethos-generated plans showed improved primary and nodal planning target volume (PTVp and PTVn, respectively) V100% and V95% coverage (p<0.001) and reduced PTVp Dmax values (p=0.023). Furthermore, the Ethos template-generated plans had lower spinal cord Dmax, lungs V5Gy, and heart V25Gy, V30Gy, and V45Gy values (p≤0.021). However, Ethos esophagus metrics (mean, V35Gy, V50Gy, Dmax) and brachial plexus metrics (Dmax) were greater than Eclipse (p≤0.008), but were still clinically acceptable. A large majority (80%) of automatically generated plans had entirely per protocol or variation acceptable metrics. Three radiation oncologists qualitatively scored the Ethos plans; 78% of plans were scored as clinically acceptable during physician evaluation, with zero plans receiving scores requiring major changes. Conclusions: A standard Ethos template generated lung cancer radiotherapy plans with greater target coverage, increased spinal cord, heart, and lung V5Gy sparing, but increased esophagus and brachial plexus dose, compared to manually generated Eclipse plans. This template elucidates an efficient approach for generating automated, high quality lung radiation therapy treatment plans.

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

Stanley

J Applied Clin Med Phys

et al. 2023

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 the 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 97 patients treated from August 2021-August 2022. One thousand six hundred seventy seven individual fractions were treated and analyzed, 632(38%) were non-adaptive and 1045(62%) were adaptive. Seventy four 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 min 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 min. Conclusion:We present our institution's experience commissioning an oART program using the Ethos therapy system. It took us 12 months from project inception to the treatment of our first patient and 12 months to treat 1000 adaptive fractions. Retrospective analysis of delivered fractions showed that the average overall treatment time was approximately 35 min and the average time for the adaptive component of treatment was approximately 20 min.