Because the depth at which a proton beam is halted by tissue depends on its initial energy, intensity-modulated proton therapy (IMPT) allows the radiation field to conform closely to the 3D shape of the tumour while sparing surrounding tissue. This makes IMPT the method of choice for intricately shaped tumours in complex physiological settings. The narrow margins in these situations mean that a robust quality assurance procedure is needed so that clinicians can be confident that the planned dose is the one that is delivered to the patient.
(…) As the TPS and phantom are both commercially available, any clinic that uses IMPT based on pencil-beam scanning can use the procedure and the team’s phantom-specific correction table to verify their treatment plans. As long as absolute dose measurements are taken for each beam angle — to mitigate uncertainty related to measurement points and gantry rotation — the method provides an accurate, reproducible basis for quality assurance. “Our motivation was to realize equal access to high-quality spot-scanning proton therapy in Japan and all over the globe,” says Yasui.
https://physicsworld.com/a/triple-gaussian-model-improves-proton-therapy-plans /
https://aapm.onlinelibrary.wiley.com/doi/full/10.1002/acm2.12535
