Parotid gland sparing effect by computed tomography-based modified lower field margin in whole brain radiotherapy.
10.3857/roj.2013.31.1.12
- Author:
Oyeon CHO
;
Mison CHUN
;
Sung Ho PARK
;
Young Taek OH
;
Mi Hwa KIM
;
Hae Jin PARK
;
Sang Soo NAM
;
Jaesung HEO
;
O Kyu NOH
- Publication Type:Original Article
- Keywords:
Whole brain radiotherapy;
Parotid gland sparing;
Xerostomia;
Normal tissue complication probability
- MeSH:
Brain;
Humans;
Parotid Gland;
Xerostomia
- From:Radiation Oncology Journal
2013;31(1):12-17
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: Parotid gland can be considered as a risk organ in whole brain radiotherapy (WBRT). The purpose of this study is to evaluate the parotid gland sparing effect of computed tomography (CT)-based WBRT compared to 2-dimensional plan with conventional field margin. MATERIALS AND METHODS: From January 2008 to April 2011, 53 patients underwent WBRT using CT-based simulation. Bilateral two-field arrangement was used and the prescribed dose was 30 Gy in 10 fractions. We compared the parotid dose between 2 radiotherapy plans using different lower field margins: conventional field to the lower level of the atlas (CF) and modified field fitted to the brain tissue (MF). RESULTS: Averages of mean parotid dose of the 2 protocols with CF and MF were 17.4 Gy and 8.7 Gy, respectively (p < 0.001). Mean parotid dose of both glands > or =20 Gy were observed in 15 (28.3%) for CF and in 0 (0.0%) for MF. The whole brain percentage volumes receiving >98% of prescribed dose were 99.7% for CF and 99.5% for MF. CONCLUSION: Compared to WBRT with CF, CT-based lower field margin modification is a simple and effective technique for sparing the parotid gland, while providing similar dose coverage of the whole brain.
