ESTRO meets Asia 2024 - Abstract Book

S299

Physics - Algorithms and applications for photon and electron planning

ESTRO meets Asia 2024

1. Bao, Z., Wang, D., Chen, S. et al. Optimal dose limitation strategy for bone marrow sparing in intensity modulated radiotherapy of cervical cancer. Radiat Oncol. 2019;14: 118.

2. Huang J, Gu F, Ji T, Zhao J, Li G. Pelvic bone marrow sparing intensity modulated radiotherapy reduces the incidence of the hematologic toxicity of patients with cervical cancer receiving concurrent chemoradiotherapy: a single-center prospective randomized controlled trial. Radiat Oncol. 2020;15:180

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Digital Poster

Dosimetric comparison of two Treatment Planning Systems (TPS) for SRS treatments

Samara S Alzaidi, Johnny Morales, Young Woo Kim

Radiation Oncology Department, Chris O'Brien Lifehouse, Camperdown, Australia

Purpose/Objective:

To compare two independent treatment planning systems for SRS treatments in terms of modelling and dosimetric verification.

Material/Methods:

Two treatment planning systems, BrainLab Elements Monte Carlo (MC) and Eclipse Acuros (AXB), were commissioned for a new Varian Edge Linear Accelerator (Linac). The BrainLab Elements MC model was created using measured data as per vendor specification. The Eclipse AXB model was created using vendor provided representative data where some parameters were adjusted to match the Edge Linac measured data. Verification for both models were done using Ion Chamber and Film measurements for a set of geometric fields and treatment plans. A comparison between the two algorithms were performed based on treatment plans where a spherical target volume diameter is varied between 2 and 9 cm. The dose in the middle of the target volume was measured using an Ion Chamber and compared to the dose prediction using the two planning systems.

Results:

The percentage difference of the dose predication to the measured dose is plotted as a function of target volume equivalent sphere diameter for each algorithm as per Figure 1. The results show that the two models dose predications are similar. As the volume gets to 2 cm in diameter, the dose difference becomes bigger and the two TPSs start to have a deviation in dose prediction.