Dudouet P, Boutry C, Mounié G, Latorzeff I, Thouveny F, Redon A
Service d'oncologie, clinique du Pont-de-Chaume, groupe Oncorad Garonne, 82000 Montauban, France.
Cancer Radiother. 2009 Sep;13(5):375-83. doi: 10.1016/j.canrad.2009.06.003. Epub 2009 Jul 28.
To describe our practice day to day with a VARIAN linac "Clinac 2100" fully equipped with an On Board Imager (OBI) for patients with prostate cancer.
A volumetric and dosimetric study was performed in 2006 using ARTIVIEW software (AQUILAB) for nine patients and 76 Cone Beam CT kV (CBCT kV). We have contoured targets and organs at risk from CBCT kV slides acquisitions. Second, we achieved a dose-volume histogram (DVH) study for a patient treated in 2007 with IMRT technique in comparison with the 2006 study.
2006 analysis: The study showed a very important variability of organ measurements. Seminal vesicles were strongly influenced by adjacent organs; observed differences for prostate could be explained by contouring uncertainty on the apex. Inter-sessions motions could be observed for bladder, rectum and seminal vesicles (SV). Part of prostate volume not encompassed by PTV is about 2.5%; VS volume outside PTV is about 35%. Tumoral conformation index (TCI) is inferior to 97.5% in 22% of all cases. Anteroposterior displacements of the prostate barycentre is superior to 5mm. From this analysis, we recommended the strict respect of hygienodietetic rules, and we have adapted the system settings for better immobilization, which were applied for the 2007 study. For the 2007 analysis, since April 2007, most of patients are treated with IMRT for prostate cancer, at the second part of the radiation therapy to encompass only the prostate volume. Dose-volume histograms showed a great spreading out for 2006 patients, and not for the 2007 patient.
IMRT and IGRT should permit a margin reduction for PTV. Strict respect of hygienodietetics rules is necessary to avoid rectal distension and local recurrence.
描述我们日常使用配备有在线成像仪（OBI）的瓦里安直线加速器“Clinac 2100”对前列腺癌患者的治疗情况。
2006年使用ARTIVIEW软件（AQUILAB）对9名患者和76次锥形束CT千伏（CBCT kV）进行了容积和剂量学研究。我们从CBCT kV幻灯片采集中勾勒出靶区和危及器官。其次，与2006年的研究相比，我们对2007年接受调强放射治疗（IMRT）的一名患者进行了剂量体积直方图（DVH）研究。
2006年分析：研究显示器官测量存在非常重要的变异性。精囊受相邻器官影响很大；前列腺观察到的差异可通过尖部轮廓勾画的不确定性来解释。膀胱、直肠和精囊（SV）可观察到不同疗程间的运动。计划靶体积（PTV）未涵盖的前列腺体积部分约为2.5%；PTV外的精囊体积约为35%。在所有病例的22%中，肿瘤形态指数（TCI）低于97.5%。前列腺重心的前后位移大于5mm。基于此分析，我们建议严格遵守卫生饮食规则，并调整了系统设置以实现更好的固定，这些设置应用于2007年的研究。对于2007年的分析，自2007年4月以来，大多数前列腺癌患者在放射治疗的第二阶段接受IMRT治疗，仅涵盖前列腺体积。剂量体积直方图显示2006年患者的分布很分散，而2007年患者并非如此。
IMRT和图像引导放射治疗（IGRT）应允许缩小PTV的边界。严格遵守卫生饮食规则对于避免直肠扩张和局部复发是必要的。
