Dosimetric comparison of brachytherapy sources for high-dose-rate treatment of endometrial cancer: Ir-192, Co-60 and an electronic brachytherapy source

作者：Mobit Paul N^*; Nguyen Alex; Packianathan Satyaseelan; He Rui; Yang Claus C

来源：British Journal of Radiology, 2016, 89(1059): 20150449.

DOI：10.1259/bjr.20150449

Objective: To compare high-dose-rate (HDR) brachytherapy systems with (192I)r, Co-60 and electronic brachytherapy source (EBS) for treatment of endometrial cancers.
Methods: Two additional plans were generated per patient fraction using a Co-60 source and Xoft-EBS on 10 selected patients, previously treated with a vaginal cylinder applicator using a Ir-192 source. Dose coverage of "PTV_CYLD", a 5-mm shell surrounding the cylinder, was evaluated. Doses to the following organs at risk (OARs) the rectum, bladder and sigmoid were evaluated in terms of V-35% and V-50%, the percentage volume receiving 35% and 50% of the prescription dose, respectively, and D-2cm3, the highest dose to a 2-cm(3) volume of an OAR.
Results: Xoft-EBS reduces doses to all OARs in the lower dose range, but it does not always provide better sparing of the rectum in higher dose range as does evaluation using D-2cm3. V-150% and V-200% for PTV_CYLD was up to four times greater for Xoft-EBS plans than for plans generated with Ir-192 or Co-60. Surface mucosal (vaginal cylinder surface) doses were also 23% higher for Xoft-EBS than for Ir-192 or Co-60 plans.
Conclusion: Xoft-EBS is a suitable HDR source for vaginal applicator treatment with advantages of reducing radiation exposure to OARs in the lower dose range, while simultaneously increasing the vaginal mucosal dose. Advances in knowledge: This work presents newer knowledge in dosimetric comparison between Ir-192 or Co-60 and Xoft-EBS sources for endometrial vaginal cylinder HDR planning.

• 出版日期2016