Retrospective Dosimetric Comparison of Low-Dose-Rate and Pulsed-Dose-Rate Intracavitary Brachytherapy Using a Tandem and Mini-Ovoids

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• 作者：Firas Mourtada ; Kent A. Gifford ; Paula A. Berner ; John L. Horton ; Michael J. Price ; Ann A. Lawyer ; Patricia J. Eifel
• 关键词：Pulsed-dose-rate ; Low-dose-rate ; Brachytherapy ; Ovoids
• 刊名：Medical Dosimetry
• 出版年：2007
• 期刊代码：195_09583947
• 类别：med
• 出版时间：Autumn 2007
• 卷：32
• 期：3
• 页码：181-187
• 文件大小：1903 K

摘要

The purpose of this study was to compare the dose distribution of Iridium-192 (¹⁹²Ir) pulsed-dose-rate (PDR) brachytherapy to that of Cesium-137 (¹³⁷Cs) low-dose-rate (LDR) brachytherapy around mini-ovoids and an intrauterine tandem. Ten patient treatment plans were selected from our clinical database, all of which used mini-ovoids and an intrauterine tandem. A commercial treatment planning system using AAPM TG43 formalism was used to calculate the dose in water for both the ¹³⁷Cs and ¹⁹²Ir sources. For equivalent system loadings, we compared the dose distributions in relevant clinical planes, points A and B, and to the ICRU bladder and rectal reference points. The mean PDR doses to points A and B were 3%± 1%and 6%± 1%higher than the LDR doses, respectively. For the rectum point, the PDR dose was 4%± 3%lower than the LDR dose, mainly because of the ¹⁹²Ir PDR source anisotropy. For the bladder point, the PDR dose was 1%± 4%higher than the LDR dose. We conclude that the PDR and LDR dose distributions are equivalent for intracavitary brachytherapy with a tandem and mini-ovoids. These findings will aid in the transfer from the current practice of LDR intracavitary brachytherapy to PDR for the treatment of gynecologic cancers.