S1867
Physics - Dose prediction/calculation, optimisation and applications for photon and electron planning
ESTRO 2026
treatment plans were created for Phase 2: one utilizing the BDP feature and the other SP, allowing for a direct dosimetric comparison of target volume, Organ at risk (OAR), normal tissue exposures, conformity index (CI) and Homogeneity index (HI). Results:
acceptable for palliative care. The approach reduces treatment delays, improves patient comfort, and maintains dosimetric accuracy. Crucially, the integration of Failure Mode and Effects Analysis (FMEA) allowed systematic identification and mitigation of potential risks, ensuring patient safety throughout the workflow. Beyond palliative care, this sim-free approach will provide a cost-effective proof of concept for adaptive radiotherapy. Future work will focus on full prospective implementation, optimizing efficiency, patient-centered care, and safe expansion to other radiotherapy indications. References: 1) Nelissen, K. J., Versteijne, E., Senan, S., Hoffmans, D., Slotman, B. J., & Verbakel, W. F. a. R. (2022). Evaluation of a workflow for cone - beam CT - guided online adaptive palliative radiotherapy planned using diagnostic CT scans. Journal of Applied Clinical Medical Physics, 24(3), e13841.2) Schuler, T., Roderick, S., Wong, S., ... , Porter, B., Booth J., Eade, T. (2024). Real- World Implementation of Simulation-Free Radiation Therapy (SFRT-1000): A Propensity Score-Matched analysis of 1000 consecutive palliative courses delivered in routine care. International Journal of Radiation Oncology*Biology*Physics, 121(3), 585–595. Keywords: simulation free RT, FMEA Comparison of Sequential Planning (SP) versus Bias Dose Planning (BDP) in Volumetric Modulated Arc Therapy (VMAT) -based Breast Radiotherapy Boost Thirumal M 1 , Palanivelu D 2 , Chandramouli Ramalingam 1 , Ajay Kumar Kondeti 1 1 Radiation Oncology, All India Institute of Medical Sciences (AIIMS), Bibinagar, Hyderabad, India. 2 Radiation Oncology, Manipal hospital, Bengaluru, Bengaluru, India Purpose/Objective: This study aims to evaluate and compare the dosimetric parameters of breast cancer radiotherapy plans using Volumetric Modulated Arc Therapy (VMAT), specifically contrasting the use of the bias dose planning (BDP) feature with sequential planning (SP) without bias in the Monaco Treatment Planning System (TPS). Material/Methods: A total of twenty breast cancer patients were randomly selected for this study, which followed a two-phase treatment regimen. In Phase 1, a dose of 40 Gy was delivered using the Elekta Versa HD, and the treatment plans were generated with 6 MV beams in the Monaco TPS using the VMAT technique. Phase 2 involved a sequential boost, delivering an additional 12.5 Gy, also using VMAT. For each patient, two Digital Poster 2032
Both the Bias Dose Plan (BDP) and Sequential Plan (SP) achieved comparable target volume coverage, with similar conformity and homogeneity indices. However, BDP demonstrated superior sparing of organs at risk (OARs). Specifically, BDP significantly reduced the mean doses to the left lung (1496.4 {plus minus} 47.9 cGy vs. 1594 {plus minus} 189.3 cGy), right lung (465.9 {plus minus} 109.1 cGy vs. 591.6 {plus minus} 251.4 cGy), and heart (770.1 {plus minus} 232.0 cGy vs. 970.2 {plus minus} 65.5 cGy) compared to SP (all p < 0.05). Additionally, volume- based metrics, including V20 and V5Gy, consistently favoured BDP. There was no substantial difference in the absolute volumes (cc) of the Body-PTV structure receiving 10% to 90% of the prescription dose between the BDP and SP plans, and the differences were not statistically significant (P {greater than or equal to} 0.05). These findings underscore the dosimetric advantage of BDP in minimizing radiation exposure to critical structures without compromising target coverage. Conclusion: The integration of the bias dose feature in VMAT- based breast cancer radiotherapy planning offers
Made with FlippingBook - Share PDF online