An end-to-end test for MR-guided online adaptive radiotherapy.

An end-to-end test for MR-guided online adaptive radiotherapy.
Phys Med Biol. 2020 Apr 15;:
Authors: Hoffmans D, Niebuhr NI, Bohoudi O, Pfaffenberger A, Palacios MA
Abstract
In the evolving field of adaptive MR guided radiotherapy, the need for dedicated procedures for acceptance and quality assurance is increasing. Research has been devoted to MR compatible dosimeters and phantoms, but to date no end-to-end test has been presented that covers an MRgRT workflow. Such an end-to-end test should comprise each step of the workflow and include all associated uncertainties. The purpose of this study was to investigate the usability of an anthropomorphic deformable and multimodal pelvis (ADAM-pelvis) phantom in combination with film dosimetry for end-to-end testing of an MRgRT adaptive workflow. The ADAM-pelvis phantom included surrogates for muscle tissue, adipose and bone, as well as deformable silicone organs mimicking a prostate patient. At the interfaces of the critical structures (bladder and rectum), small pieces of GafChromic EBT3 films were placed to measure delivered dose. Pre-treatment MR imaging of the phantom was used to delineate the prostate, rectum and bladder and to generate a treatment plan to deliver 2 Gy to the prostate. Electron density (ED) map from CT imaging was used for dose calculation after deformable image registration (DIR) to the pre-treatment MR scan. At each fraction, bladder- and rectum filling was varied an...

Source: Physics in Medicine and Biology - April 14, 2020 Category: Physics Authors: Hoffmans D, Niebuhr NI, Bohoudi O, Pfaffenberger A, Palacios MA Tags: Phys Med Biol Source Type: research