TY  - JOUR
AU  - Hoffmans, Daan
AU  - Niebuhr, Nina Isabell
AU  - Bohoudi, Omar
AU  - Pfaffenberger, Asja
AU  - Palacios, Miguel A
TI  - An end-to-end test for MR-guided online adaptive radiotherapy.
JO  - Physics in medicine and biology
VL  - 65
IS  - 12
SN  - 1361-6560
CY  - Bristol
PB  - IOP Publ.
M1  - DKFZ-2020-00819
SP  - Article number 125012
PY  - 2020
N1  - Volume 65, Issue 12, 21 June 2020, Article number 125012
AB  - 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 and a new adapted plan was generated. Dose calculation was performed using both a DIR-based ED map and a CT-based ED map after acquisition of a new CT scan of the phantom at each fraction. Dose calculations were performed taking into account the magnetic field. A good agreement between measured and calculated dose was found using both, the CT-derived and the DIR-based ED map (2.0
LB  - PUB:(DE-HGF)16
C6  - pmid:32294637
DO  - DOI:10.1088/1361-6560/ab8955
UR  - https://inrepo02.dkfz.de/record/154497
ER  -