PURPOSE: Organ motion is recognized as the principal source of inaccuracy in bladder radiotherapy (RT), but there is currently little information on intrafraction bladder motion. METHODS AND MATERIALS: We used cine-magnetic resonance imaging (cine-MRI) to study bladder motion relevant to intrafraction RT delivery. On two occasions, a 28 minute cine-MRI sequence was acquired from 10 bladder cancer patients and 5 control participants immediately after bladder emptying, after abstinence from drinking for the preceding hour. From the resulting cine sequences, bladder motion was subjectively assessed. To quantify bladder motion, the bladder was contoured in imaging volume sets at 0, 14, and 28 min to measure changes to bladder volumes, wall displacements, and center of gravity (COG) over time. RESULTS: The dominant source of bladder motion during imaging was bladder filling (up to 101% volume increase); rectal and small bowel movements were transient, with minimal impact. Bladder volume changes were similar for all participants. However for bladder cancer patients, wall displacements were larger (up to 58 mm), less symmetrical, and more variable compared with nondiseased control bladders. CONCLUSIONS: Significant and individualized intrafraction bladder wall displacements may occur during bladder RT delivery. This important source of inaccuracy should be incorporated into treatment planning and verification.
PURPOSE: Organ motion is recognized as the principal source of inaccuracy in bladder radiotherapy (RT), but there is currently little information on intrafraction bladder motion. METHODS AND MATERIALS: We used cine-magnetic resonance imaging (cine-MRI) to study bladder motion relevant to intrafraction RT delivery. On two occasions, a 28 minute cine-MRI sequence was acquired from 10 bladder cancerpatients and 5 control participants immediately after bladder emptying, after abstinence from drinking for the preceding hour. From the resulting cine sequences, bladder motion was subjectively assessed. To quantify bladder motion, the bladder was contoured in imaging volume sets at 0, 14, and 28 min to measure changes to bladder volumes, wall displacements, and center of gravity (COG) over time. RESULTS: The dominant source of bladder motion during imaging was bladder filling (up to 101% volume increase); rectal and small bowel movements were transient, with minimal impact. Bladder volume changes were similar for all participants. However for bladder cancerpatients, wall displacements were larger (up to 58 mm), less symmetrical, and more variable compared with nondiseased control bladders. CONCLUSIONS: Significant and individualized intrafraction bladder wall displacements may occur during bladder RT delivery. This important source of inaccuracy should be incorporated into treatment planning and verification.
Authors: Justin T Sick; Nicholas J Rancilio; Caroline V Fulkerson; Jeannie M Plantenga; Deborah W Knapp; Keith M Stantz Journal: Phys Imaging Radiat Oncol Date: 2019-11-15
Authors: Adham Hijab; Boris Tocco; Ian Hanson; Hanneke Meijer; Christina Junker Nyborg; Anders Smedegaard Bertelsen; Robert Jan Smeenk; Gillian Smith; Jeff Michalski; Brian C Baumann; Shaista Hafeez Journal: Front Oncol Date: 2021-02-25 Impact factor: 6.244
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