Presented at American College of Veterinary Radiologists Annual Meeting, Memphis, TN, October 23, 2009 (preliminary data).
USE OF CONE-BEAM COMPUTED TOMOGRAPHY TO CHARACTERIZE DAILY URINARY BLADDER VARIATIONS DURING FRACTIONATED RADIOTHERAPY FOR CANINE BLADDER CANCER
Version of Record online: 23 JUN 2011
© 2011 Veterinary Radiology & Ultrasound
Veterinary Radiology & Ultrasound
Volume 52, Issue 5, pages 580–588, September/October 2011
How to Cite
NIESET, J. R., HARMON, J. F. and LARUE, S. M. (2011), USE OF CONE-BEAM COMPUTED TOMOGRAPHY TO CHARACTERIZE DAILY URINARY BLADDER VARIATIONS DURING FRACTIONATED RADIOTHERAPY FOR CANINE BLADDER CANCER. Veterinary Radiology & Ultrasound, 52: 580–588. doi: 10.1111/j.1740-8261.2011.01838.x
- Issue online: 16 SEP 2011
- Version of Record online: 23 JUN 2011
- Received February 19, 2010; accepted for publication May 3, 2011.
- bladder cancer;
- cone-beam computed tomography;
- planning target volume;
- radiation therapy;
Urinary bladder cancer is difficult to treat accurately with fractionated radiation therapy (RT) due to daily positional changes of the bladder and surrounding soft-tissue structures. We quantified the daily motion experienced by the canine bladder with patients in dorsal vs. sternal vs. lateral recumbency. We also described the dose distribution for three different planning target volume expansions (5, 10, and 15 mm) for each of the three positions to ensure adequate bladder dose and minimize irradiation of nearby healthy tissues. Analysis was based on data from retrospective daily cone-beam computed tomography (CT) (CBCT) images obtained for positioning of canine patients undergoing routine RT. Organs of interest were contoured on each CBCT data set and the images, along with the contours, were registered to the original planning CT. All measurements were made relative to the planning CT and dosimetric data for the organs of interest was determined using a dose volume histogram generated from sample parallel-opposed beam configuration. There was a wide range in bladder position throughout treatment. The least amount of bladder variation and the lowest rectal dose was with dogs in lateral recumbency. It was also determined that a margin of 10 mm would allow for sufficient dose to be delivered to the bladder while minimizing rectal dose.