Rockey William M, Bhatia Sudershan K, Jacobson Geraldine M, Kim Yusung
Radiation Oncology Department, The University of Iowa.
J Contemp Brachytherapy. 2013 Mar;5(1):17-22. doi: 10.5114/jcb.2013.34449. Epub 2013 Mar 29.
We perform a clinical retrospective study to determine whether a vaginal balloon-packing system provides a dosimetric reduction to organs at risk (OARs) versus traditional gauze packing for gynecological high-dose-rate brachytherapy (HDR-BT). We also test various balloon filling materials for optimizing imaging quality.
Filling materials for balloon-packing were evaluated based on imaging quality with X-ray, computerized tomography, and magnetic resonance imaging modalities. We then retrospectively reviewed 45 HDR-BT plans of 18 patients performed with gauze packing and 39 plans of 16 patients performed with balloon-packing. Twelve patients received both gauze and balloon-packing. HDR-BT was delivered with an iridium-192 afterloader and a Fletcher-Suit-Declos-style T&O applicator. At each fraction, 3D imaging was obtained. The D2cc values of OARs were calculated, as well as ICRU-defined point doses.
In the 84 HDR fractions reviewed, vaginal balloon-packing provides statistically equivalent doses to rectum, bladder, and sigmoid compared to gauze packing. On average balloon-packing produced average reductions of 3.3% and 6.9% in the rectal and sigmoid D2cc doses and an increase of 3.2% to the bladder D2cc dose (normalized to prescription dose), although none of these values were statistically significant for the twelve patients who received both gauze and balloon-packing (32 and 40 total fractions, respectively).
In the 84 HDR fractions analyzed, vaginal balloon-packing is as effective as gauze packing for dose sparing to the rectum, bladder, and sigmoid. A 1: 1 solution of saline and contrast for filling material enables easy contouring for image-guided HDR with minimal artefacts.
我们进行了一项临床回顾性研究，以确定与传统纱布填塞相比，阴道球囊填塞系统在妇科高剂量率近距离放疗（HDR-BT）中是否能降低危及器官（OARs）的剂量。我们还测试了各种球囊填充材料以优化成像质量。
基于X射线、计算机断层扫描和磁共振成像模态的成像质量评估球囊填塞的填充材料。然后，我们回顾性分析了18例患者使用纱布填塞的45个HDR-BT计划以及16例患者使用球囊填塞的39个计划。12例患者同时接受了纱布和球囊填塞。使用铱-192后装治疗机和Fletcher-Suit-Declos式T&O施源器进行HDR-BT。每次分割时，获取三维图像。计算OARs的D2cc值以及ICRU定义的点剂量。
在回顾的84个HDR分割中，与纱布填塞相比，阴道球囊填塞对直肠、膀胱和乙状结肠的剂量在统计学上相当。平均而言，球囊填塞使直肠和乙状结肠的D2cc剂量分别平均降低了3.3%和6.9%，膀胱D2cc剂量增加了3.2%（相对于处方剂量进行归一化），尽管对于同时接受纱布和球囊填塞的12例患者（分别为32和40个总分割），这些值均无统计学意义。
在分析的84个HDR分割中，阴道球囊填塞在保护直肠、膀胱和乙状结肠剂量方面与纱布填塞同样有效。用生理盐水和造影剂按1:1比例混合作为填充材料，能在图像引导的HDR中轻松勾勒轮廓且伪影最少。
