Comparative Study of Plan Robustness for Breast Radiotherapy: Volumetric Modulated Arc Therapy Plans with Robust Optimization versus Manual Flash Approach

Abstract

A previous study investigated robustness of manual flash (MF) and robust optimized (RO) volumetric modulated arc therapy plans for breast radiotherapy based on five patients in 2020 and indicated that the RO was more robust than the MF, although the MF is still current standard practice. The purpose of this study was to compare their plan robustness in terms of dose variation to clinical target volume (CTV) and organs at risk (OARs) based on a larger sample size. This was a retrospective study involving 34 female patients. Their plan robustness was evaluated based on measured volume/dose difference between nominal and worst scenarios (ΔV/ΔD) for each CTV and OARs parameter, with a smaller difference representing greater robustness. Paired sample t-test was used to compare their robustness values. All parameters (except CTV ΔD98%) of the RO approach had smaller ΔV/ΔD values than those of the MF. Also, the RO approach had statistically significantly smaller ΔV/ΔD values (p < 0.001–0.012) for all CTV parameters except the CTV ΔV95% and ΔD98% and heart ΔDmean. This study’s results confirm that the RO approach was more robust than the MF in general. Although both techniques were able to generate clinically acceptable plans for breast radiotherapy, the RO could potentially improve workflow efficiency due to its simpler planning process.

Comparative Study of Eclipse and RayStation Multi-Criteria Optimization-Based Prostate Radiotherapy Treatment Planning Quality

“…The OARs, CTV and PTV were subsequently reviewed and approved by another radiation oncologist with associate consultant grade or above for clinical use previously. These arrangements enabled the OARs and target volumes segmentation being more standardized [ 7 , 8 , 9 ].…”

“…Mean and standard deviations were calculated for: (1) the percentage differences of the PTV 76 D 98% and rectum D 50% to indicate the discrepancies between the Pareto optimal and final deliverable plans; and (2) the doses received by structures listed in Table 2 , HI and CI of the 25 selected final deliverable plans. A paired sample t -test was employed to compare these mean values of the two treatment planning systems with a p -value less than 0.05 representing statistically significant difference [ 8 , 9 , 17 , 37 , 38 ].…”

“…All (25) CT datasets of the selected patients acquired from the CT Big Bore simulator in Digital Imaging and Communications in Medicine (DICOM) format were imported into the Eclipse version 16.1 treatment planning system for clinical target volume (CTV), PTV and OARs segmentation. The OARs (bladder, femoral head, rectum and small bowel) were manually contoured by a radiation therapist with more than 15 years of experience [7][8][9]. The CTV and PTV (prostate and seminal vesicles) were manually segmented by a radiation oncologist experienced in prostate cancer RT, based on European Society for Therapeutic Radiology and Oncology (ESTRO) consensus guidelines [30].…”

“…Although prostate RT is a relatively less invasive treatment, use of ionizing radiation in this treatment may result in adverse effects on the rectum such as pain, bleeding and increase of stool frequency [5][6][7]. RT planning plays a crucial role in minimizing the dose received by nearby healthy structures known as organs at risk (OARs), and hence the adverse effects, while accurately delivering the prescribed radiation amount to the Diagnostics 2024, 14, 465 2 of 12 tumor (planning target volume (PTV)) for effective treatment [8][9][10]. However, the rectum being in close proximity to the PTV, along with their overlapping regions, presents a unique challenge in prostate RT planning [11][12][13].…”