Author: Gueorgui Gueorguiev, Kavya Thaniyarasu 👨🔬
Affiliation: University of Bologna, National Centre of Radiobiology and Radiation Protection 🌍
Purpose: This study investigates the clinical viability of double scattering proton therapy treatment planning for thoracic malignancies using single or multiple treatment fields. The aim of this study is to present the optimal clinical plan achieving both maximum treatment target coverage and minimizing exposure to healthy tissues and organs.
Methods: Eighteen treatment plans were created using Raysearch RayStation treatment planning system for upper right lung malignancy and having between one and four treatment fields. Tumour dose was set to 60Gy aiming at covering at least 97% of the target volume. The treatment plan evaluation was done in accordance with tumour coverage and dose constraints for organs at risk (OAR) used in our clinic. Comparative analysis identified the best and the worst plans, as well as all were labelled as either clinically viable, some-what clinically viable and not clinically viable.
Results: In general, two-field plans produced most clinically viable plans, as the plan with gantry angles 0 and 270 degrees yielded the best results by ensuring optimum coverage of the tumour and OAR dose constraints were met. The single-proton field plans had inadequate tumour coverage and in some instances overdosed OAR, and hence are not clinically fit. The worst plan had single gantry angle of 270 degrees. Plans using three or four treatment fields achieved adequate tumour coverage, but overdosed some OAR, therefore were clinically non-viable.
Conclusion: Current work demonstrated that two proton field plans were adequate in both achieving thoracic tumour coverage and in sparing the OAR. Less or more fields did not provide additional clinical advantages.