Factors for Predicting Rectal Dose of High-Dose-Rate Intracavitary Brachytherapy After Pelvic Irradiation in Patients With Cervical Cancer: A Retrospective Study With Radiography-Based Dosimetry

Journal Article · Mon Feb 01 04:00:00 EST 2010 · International Journal of Radiation Oncology, Biology and Physics

DOI:https://doi.org/10.1016/j.ijrobp.2009.02.018· OSTI ID:21372065

Chongjong, Wang; Jenhong, Lan; Huichun, Chen ^[1]; Fumin, Fang ^[1]; Hsu, H -C ^[1]; Yujie, Huang; Changyu, Wang; Yuming, Wang ^[1]

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1. Department of Radiation Oncology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Taiwan (China)

Purpose: To evaluate the predictive factors for rectal dose of the first fraction of high-dose-rate intracavitary brachytherapy (HDR-ICBT) in patients with cervical cancer. Methods and Materials: From March 1993 through February 2008, 946 patients undergoing pelvic irradiation and HDR-ICBT were analyzed. Examination under anesthesia (EUA) at the first implantation of the applicator was usually performed in the early period. Rectal point was determined radiographically according to the 38th Report of the International Commission of Radiation Units and Measurements (ICRU). The ICRU rectal dose (PRD) as a percentage of point A dose was calculated; multiple linear regression models were used to predict PRD. Results: Factors influencing successful rectal dose calculation were EUA (p < 0.001) and absence of diabetes (p = 0.047). Age (p < 0.001), body weight (p = 0.002), diabetes (p = 0.020), and EUA (p < 0.001) were independent factors for the PRD. The predictive equation derived from the regression model was PRD (%) = 57.002 + 0.443 x age (years) - 0.257 x body weight (kg) + 6.028 x diabetes (no: 0; yes: 1) - 8.325 x EUA (no: 0; yes: 1) Conclusion: Rectal dose at the first fraction of HDR-ICBT is positively influenced by age and diabetes, and negatively correlated with EUA and body weight. A small fraction size at point A may be considered in patients with a potentially high rectal dose to reduce the biologically effective dose if the ICRU rectal dose has not been immediately obtained in the first fraction of HDR-ICBT.

• OSTI ID: 21372065
• Journal Information: International Journal of Radiation Oncology, Biology and Physics, Journal Name: International Journal of Radiation Oncology, Biology and Physics Journal Issue: 2 Vol. 76; ISSN IOBPD3; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BODY
BRACHYTHERAPY
DIGESTIVE SYSTEM
DISEASES
DOSE RATES
DOSIMETRY
GASTROINTESTINAL TRACT
INTESTINES
LARGE INTESTINE
MEDICINE
NEOPLASMS
NUCLEAR MEDICINE
ORGANS
PELVIS
RADIOLOGY
RADIOTHERAPY
RECTUM
THERAPY
UROGENITAL SYSTEM DISEASES