Lotte J Lutkenhaus1, Jorrit Visser2, Rianne de Jong2, Maarten C C M Hulshof2, Arjan Bel2. 1. Department of Radiation Oncology, Academic Medical Center, Amsterdam, The Netherlands. Electronic address: l.j.lutkenhaus@amc.uva.nl. 2. Department of Radiation Oncology, Academic Medical Center, Amsterdam, The Netherlands.
Abstract
PURPOSE: To account for variable bladder size during bladder cancer radiotherapy, a daily plan selection strategy was implemented. The aim of this study was to calculate the actually delivered dose using an adaptive strategy, compared to a non-adaptive approach. MATERIAL AND METHODS: Ten patients were treated to the bladder and lymph nodes with an adaptive full bladder strategy. Interpolated delineations of bladder and tumor on a full and empty bladder CT scan resulted in five PTVs for which VMAT plans were created. Daily cone beam CT (CBCT) scans were used for plan selection. Bowel, rectum and target volumes were delineated on these CBCTs, and delivered dose for these was calculated using both the adaptive plan, and a non-adaptive plan. RESULTS: Target coverage for lymph nodes improved using an adaptive strategy. The full bladder strategy spared the healthy part of the bladder from a high dose. Average bowel cavity V30Gy and V40Gy significantly reduced with 60 and 69ml, respectively (p<0.01). Other parameters for bowel and rectum remained unchanged. CONCLUSIONS: Daily plan selection compared to a non-adaptive strategy yielded similar bladder coverage and improved coverage for lymph nodes, with a significant reduction in bowel cavity V30Gy and V40Gy only, while other sparing was limited.
PURPOSE: To account for variable bladder size during bladder cancer radiotherapy, a daily plan selection strategy was implemented. The aim of this study was to calculate the actually delivered dose using an adaptive strategy, compared to a non-adaptive approach. MATERIAL AND METHODS: Ten patients were treated to the bladder and lymph nodes with an adaptive full bladder strategy. Interpolated delineations of bladder and tumor on a full and empty bladder CT scan resulted in five PTVs for which VMAT plans were created. Daily cone beam CT (CBCT) scans were used for plan selection. Bowel, rectum and target volumes were delineated on these CBCTs, and delivered dose for these was calculated using both the adaptive plan, and a non-adaptive plan. RESULTS: Target coverage for lymph nodes improved using an adaptive strategy. The full bladder strategy spared the healthy part of the bladder from a high dose. Average bowel cavity V30Gy and V40Gy significantly reduced with 60 and 69ml, respectively (p<0.01). Other parameters for bowel and rectum remained unchanged. CONCLUSIONS: Daily plan selection compared to a non-adaptive strategy yielded similar bladder coverage and improved coverage for lymph nodes, with a significant reduction in bowel cavity V30Gy and V40Gy only, while other sparing was limited.
Authors: Duncan den Boer; Mariska D den Hartogh; Alexis N T J Kotte; Jochem R N van der Voort van Zyp; Juus L Noteboom; Gijsbert H Bol; Thomas Willigenburg; Anita M Werensteijn-Honingh; Ina M Jürgenliemk-Schulz; Astrid L H M W van Lier; Petra S Kroon Journal: Phys Imaging Radiat Oncol Date: 2021-11-20
Authors: Yingqiu Song; Beth Erickson; Xiaojian Chen; Guiling Li; Gang Wu; Eric Paulson; Paul Knechtges; X Allen Li Journal: Oncotarget Date: 2018-01-06