Effects of Bladder Distension on Organs at Risk in 3D Image-Based Planning of Intracavitary Brachytherapy for Cervical Cancer
- Department of Radiation Oncology, University of Alabama Medical Center, Birmingham, AL (United States)
- Department of Medical Statistics Section of the Comprehensive Cancer Center, University of Alabama Medical Center, Birmingham, AL (United States)
Purpose: To investigate the effects of bladder distension on organs at risk (OARs) in the image-based planning of intracavitary brachytherapy for cervical cancer. Methods and Materials: Thirteen patients with cancer of the cervix were treated with high-dose radiation brachytherapy (800 cGy/fraction for 3 fractions). For the three-dimensional (3D) analysis, pelvic CT scans were obtained from patients with indwelling catheters in place (defined as empty bladder) and from patients who received 180-cc injections of sterile water in their bladders (defined as full bladder). To compare the International Commission on Radiation Units and Measurements (ICRU) point doses with 3D-volume doses, the volume dose was defined by using two different criteria, D{sub 2cc} (the minimum dose value in a 2.0-cm{sup 3} volume receiving the highest dose) and D{sub 50%} (the dose received by 50% of the volume of the OAR) for OARs. Results: The bladder D{sub 2cc} was located more cranially in the bladder base and was distributed in multiple spots in 46% of patients. The rectal D{sub 2cc} was located in the area of the ICRU point as a single 'hot spot.' For patients with a full bladder, the mean bladder D{sub 2cc} increased from 634 to 799 cGy (28.8%, p = 0.002). However, the bowel D{sub 2cc} decreased from 475 to 261 cGy (45.0%, p < 0.001). There were no substantial differences in rectal and sigmoid D{sub 2cc} values. However, the mean D{sub 50%} values of both the bladder and the bowel decreased from 108 to 80 cGy (23.7%, p < 0.001) and from 282 to 221 cGy (19.7%, p = 0.004) with a full bladder, respectively. Conclusions: An increase in bladder volume resulted in a significant reduction in bowel D{sub 2cc} values at the expense of an increase in bladder D{sub 2cc} values. Treatment with a distended bladder is preferable to protect the bowel.
- OSTI ID:
- 21372064
- Journal Information:
- International Journal of Radiation Oncology, Biology and Physics, Vol. 76, Issue 2; Other Information: DOI: 10.1016/j.ijrobp.2009.02.002; PII: S0360-3016(09)00189-8; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0360-3016
- Country of Publication:
- United States
- Language:
- English
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