Rovirosa Angeles, Noorian Faegheh, Cordoba Sofia, León Francesc, Lancellotta Valentina, Tagliaferri Luca, Herrreros Antonio
Fonaments Clinics Department, Universitat de Barcelona, Barcelona, Spain.
Radiation Oncology Department, Hospital Clínic-Universitat de Barcelona, IDIBAPS, Barcelona, Spain.
J Contemp Brachytherapy. 2024 Oct;16(5):352-361. doi: 10.5114/jcb.2024.144183. Epub 2024 Oct 16.
Currently, there are many schedules for exclusive vaginal cuff brachytherapy (VCB). In 3D treatment planning for VCB dosimetry, parameters have not been analyzed. The aim of this study was to compare the most common schedules using dose-volume histogram metrics.
Three different computed tomography (CT) studies for vaginal cylinders of 3.5 cm, 3 cm, and 2.5 cm were performed. Clinical target volume (CTV) was delineated for 3 cm and 4 cm of vaginal length. Twelve schedules were analyzed obtaining overall vaginal surface dose (Gy) (EQD α/β = 10 and α/β = 3), overall D CTV (Gy), and overall D for organs at risk (OARs), such as vagina, rectum, sigmoid, rectum, and bladder. Prescription at 5 mm from the applicator surface and at the surface were analyzed for each case.
The overall vaginal surface dose and dose to CTV varied widely among the different schedules, and CTV delineation was necessary in case of surface prescription. The applicator diameter of 3.5 cm showed the best dosimetry results for vaginal surface dose. The overall D OARs' doses changed in the different CT studies.
This dosimetry study allows for better selection of fractionation schedules, and helps to unify treatments among centers. Prospective studies are needed to establish the best schedule and CTV length in each patient using clinical data, such as late toxicity and relapses.
目前，有多种用于单纯阴道袖状近距离放射治疗（VCB）的方案。在VCB剂量测定的三维治疗计划中，尚未对参数进行分析。本研究的目的是使用剂量体积直方图指标比较最常见的方案。
对3.5厘米、3厘米和2.5厘米的阴道圆柱体进行了三项不同的计算机断层扫描（CT）研究。对3厘米和4厘米的阴道长度勾画临床靶区（CTV）。分析了12种方案，得出整个阴道表面剂量（Gy）（等效剂量α/β = 10和α/β = 3）、整个CTV的剂量（Gy）以及对危及器官（OARs）如阴道、直肠、乙状结肠、直肠和膀胱的整个剂量。对每种情况分析了距施源器表面5毫米处和表面处的处方剂量。
不同方案之间整个阴道表面剂量和CTV剂量差异很大，在表面处方的情况下，勾画CTV是必要的。3.5厘米的施源器直径在阴道表面剂量方面显示出最佳的剂量测定结果。不同CT研究中OARs的整个剂量有所变化。
这项剂量测定研究有助于更好地选择分割方案，并有助于各中心统一治疗。需要进行前瞻性研究，以利用临床数据（如晚期毒性和复发情况）为每位患者确定最佳方案和CTV长度。
