Non-rigid deformation of treatment plans for on-line adaptive protontherapy

Details

Supervisors

Sterpin, Edmond ; Lee, John Aldo

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil biomédical

Abstract

External radiotherapy is a major component of cancer treatment. Its objective is to deliver a high measure of radiation to tumors while minimizing the dose inflicted to healthy tissues. Protons have the ability to deliver a peak of energy (the "Bragg peak") in a precise location depending on the atomic composition and densities of the tissues in their path, making them highly suitable for radiotherapy. Because the anatomy of the patient is continuously changing during the course of the treatment that may last more than 30 days, the position of the Bragg peak is subject to uncertainties, which may have dramatic consequences for the patient. The goal of this master thesis is to tune the treatment to day-to-day anatomical changes by performing the so-called "adaptive planning". We submit an original strategy where the treatment plan, optimized before the start of the treatment and approved by a radiation oncologist, is adjusted to the new anatomy. Three test cases have been designed: 1) anatomical changes around a tumor with unmodified position and shape; 2) tumor displacement; and 3) tumor reduction. The evaluation of a plan is conducted by analysing the dose volume histogram of the predicted dose by a Monte Carlo algorithm. Except for the tumor reduction, our adapted plans manage to produce a dose close to the desired one. In conclusion, non-rigid deformation of treatment plan could be used in addition of other method to perform efficient adaptive protontherapy.