Sud Shivani, Roth Toni, Jones Ellen
University of North Carolina School of Medicine, Chapel Hill, NC.
Alpert Medical School of Brown University, Providence, RI.
J Contemp Brachytherapy. 2018 Feb;10(1):32-39. doi: 10.5114/jcb.2018.74316. Epub 2018 Feb 28.
Intra-vaginal packing is used to fix the applicator and displace organs at risk (OAR) during high-dose-rate intracavitary tandem and ovoid brachytherapy (HDR-ICB). We retain the speculum from applicator placement as a dual-function bladder and rectum retractor during treatment. Our objective is to review salient techniques for OAR displacement, share our packing technique, and determine the reduction in dose to OAR and inter-fraction variability of dose to OAR, associated with speculum-based vaginal packing (SBVP) in comparison to conventional gauze packing during HDR-ICB.
We reviewed HDR-ICB treatment plans for 45 patients, including 10 who underwent both conventional gauze packing and SBVP. Due to institutional inter-provider practice differences, patients non-selectively received either packing procedure. Packing was performed under conscious sedation, followed by cone beam computed tomography used for dosimetric planning. Maximum absolute and percent-of-prescription dose to the International Commission of Radiation Units bladder and rectal points in addition to D, D, and D volumes of the bladder and rectum were analyzed and compared for each packing method using an independent sample -test.
Of the 179 fractions included, 73% and 27% used SBVP and gauze packing, respectively. For patients prescribed 6 Gy to point A, SBVP was associated with reduced mean D bladder dose, inter-fraction variability in D bladder dose by 9.3% ( = 0.026) and 9.0%, respectively, and statistically equivalent rectal D, D, and D. Patients prescribed 5.5 Gy or 5 Gy to point A after dose optimization, were less likely to benefit from SBVP. In the intra-patient comparison, 80% of patients had reduction in at least one rectum or bladder parameter.
In patients with conducive anatomy, SBVP is a cost-efficient packing method that is associated with improved bladder sparing and comparable rectal sparing relative to gauze packing during HDR-ICB without general anesthesia.
在高剂量率腔内串联卵圆体近距离放射治疗（HDR-ICB）期间，阴道内填塞用于固定施源器并移位危及器官（OAR）。在治疗过程中，我们保留施源器放置时的窥器作为膀胱和直肠的双功能牵开器。我们的目的是回顾OAR移位的显著技术，分享我们的填塞技术，并确定与传统纱布填塞相比，基于窥器的阴道填塞（SBVP）在HDR-ICB期间对OAR的剂量降低以及OAR剂量的分次间变异性。
我们回顾了45例患者的HDR-ICB治疗计划，其中10例患者同时接受了传统纱布填塞和SBVP。由于机构内不同提供者的实践差异，患者非选择性地接受了两种填塞程序中的一种。填塞在清醒镇静下进行，随后进行锥束计算机断层扫描用于剂量学规划。使用独立样本t检验分析并比较每种填塞方法对国际辐射单位委员会膀胱和直肠点的最大绝对剂量和处方剂量百分比，以及膀胱和直肠的D、D和D体积。
在纳入的179个分次中，分别有73%和27%使用了SBVP和纱布填塞。对于处方A点剂量为6 Gy的患者，SBVP分别使膀胱平均D剂量降低、膀胱D剂量的分次间变异性降低9.3%（P = 0.026）和9.0%，直肠D、D和D在统计学上相当。在剂量优化后处方A点剂量为5.5 Gy或5 Gy的患者中，从SBVP中获益的可能性较小。在患者内比较中。80%的患者至少有一个直肠或膀胱参数降低。
在解剖结构有利的患者中，SBVP是一种经济高效的填塞方法，与HDR-ICB期间不使用全身麻醉的纱布填塞相比，它能更好地保护膀胱，直肠保护效果相当。
