Bladder filling in patients undergoing prostate radiotherapy on a MR-linac: The dosimetric impact
Gillian Smith, Alex Dunlop, Helen Barnes, Trina Herbert, R. Lawes, Jonathan Mohajer, Alison Tree, H. McNair
Abstract
The implementation of adaptive radiotherapy for prostate cancer compensates for inter-fraction motion, at the penalty of increased time in room. The subsequent increase in bladder filling may impact dosimetry, which we have investigated on ten patients treated on the MR-linac. Patients drank water before treatment, to achieve a bladder volume of 200–300 cm3. Bladder and bowel were re-outlined offline on 140 images and plans recalculated. All mandatory bladder dose constraints and 99.1% of bowel constraints were achieved at time of treatment, despite varying bladder volumes and varying adherence to original bladder filling guidance.
Topics & Concepts
MedicineProstateRadiation therapyDosimetryNuclear medicineProstate cancerUrologyRadiologyCancerInternal medicineAdvanced Radiotherapy TechniquesProstate Cancer Diagnosis and TreatmentRadiation Therapy and Dosimetry