PMID- 31047287 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20191120 IS - 1876-7982 (Electronic) IS - 1876-7982 (Linking) VI - 47 IP - 3 DP - 2016 Sep TI - Assessment of Adaptive Margins Using a Single Planning Computed Tomography Scan for Bladder Radiotherapy. PG - 227-234 LID - S1939-8654(16)30037-6 [pii] LID - 10.1016/j.jmir.2016.05.001 [doi] AB - INTRODUCTION: A "plan of the day" (PoD) adaptive radiotherapy approach is presented for bladder cancer. The potential reduction in volumes of normal tissue and bowel bag receiving high-dose radiation is evaluated. MATERIALS AND METHODS: Planning computed tomography (pCT) and daily cone beam CT (CBCT) data sets were analyzed for eight previously treated bladder cancer patients. For each patient, a whole bladder clinical target volume (CTV) was delineated on a pCT. Then, the clinical target volume was expanded using five sets of anisotropic or isotropic margins to create five planning target volumes (PTVs). A library of five corresponding treatment PoDs was then created using volumetric modulated arc therapy. Offline PoD selection was performed by three independent radiation therapists (RTs) using daily CBCTs. Dosimetric results were compared between PoD treatments and two conventional treatments using isotropic 1.5- and 2.0-cm margins. RESULTS: The smallest PTV using 1.0-cm isotropic margins was selected most frequently (70%). Three RTs demonstrated good agreement for daily PTV selections, choosing identical PoDs for 51% of all CBCTs. In addition, acceptable dosimetric coverage of the whole bladder was achieved for all PoD selections, similar to standard treatments. The average volume of bowel bag receiving 45 and 50 Gy and normal tissue receiving 95% prescription dose was significantly (P < .01) lower for PoD treatments compared with both conventional treatments. CONCLUSIONS: A PoD strategy using one pCT with isotropic and anisotropic margins can be used to treat bladder cancer and improve sparing of the bowel bag. Minimal dosimetric differences observed between three RTs suggests that PoD strategies are feasible for clinical implementation. CI - Copyright (c) 2016 Canadian Association of Medical Radiation Technologists. Published by Elsevier Inc. All rights reserved. FAU - Canlas, Romel AU - Canlas R AD - Department of Radiation Therapy, Abbotsford Centre, BC Cancer Agency, Abbotsford, BC, Canada. Electronic address: rcanlas@bccancer.bc.ca. FAU - McVicar, Nevin AU - McVicar N AD - Department of Medical Physics, Vancouver Centre, BC Cancer Agency, Vancouver, BC, Canada. FAU - Nakano, Sandy AU - Nakano S AD - Department of Radiation Therapy, Vancouver Centre, Vancouver, BC, Canada. FAU - Sahota, Hardeep AU - Sahota H AD - Department of Radiation Therapy, Vancouver Centre, BC Cancer Agency, Vancouver, BC, Canada. FAU - Mahajan, Pulkit AU - Mahajan P AD - Department of Radiation Therapy, Centre for the Southern Interior, BC Cancer Agency, Kelowna, BC, Canada. FAU - Tyldesley, Scott AU - Tyldesley S AD - Department of Radiation Therapy, Vancouver Centre, British Columbia Cancer Agency, Vancouver, BC, Canada; Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada. LA - eng PT - Journal Article DEP - 20160620 PL - United States TA - J Med Imaging Radiat Sci JT - Journal of medical imaging and radiation sciences JID - 101469694 OTO - NOTNLM OT - Adaptive radiotherapy OT - Bladder cancer OT - Plan of the day EDAT- 2016/09/01 00:00 MHDA- 2016/09/01 00:01 CRDT- 2019/05/04 06:00 PHST- 2016/01/03 00:00 [received] PHST- 2016/04/28 00:00 [revised] PHST- 2016/05/04 00:00 [accepted] PHST- 2019/05/04 06:00 [entrez] PHST- 2016/09/01 00:00 [pubmed] PHST- 2016/09/01 00:01 [medline] AID - S1939-8654(16)30037-6 [pii] AID - 10.1016/j.jmir.2016.05.001 [doi] PST - ppublish SO - J Med Imaging Radiat Sci. 2016 Sep;47(3):227-234. doi: 10.1016/j.jmir.2016.05.001. Epub 2016 Jun 20.