Nijkamp Jasper, Pos Floris J, Nuver Tonnis T, de Jong Rianne, Remeijer Peter, Sonke Jan-Jakob, Lebesque Joos V
Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Int J Radiat Oncol Biol Phys. 2008 Jan 1;70(1):75-82. doi: 10.1016/j.ijrobp.2007.05.046. Epub 2007 Sep 17.
To evaluate the first clinical results of an off-line adaptive radiotherapy (ART) protocol for prostate cancer using kilovoltage cone-beam computed tomography (CBCT) in combination with a diet and mild laxatives.
Twenty-three patients began treatment with a planning target volume (PTV) margin of 10 mm. The CBCT scans acquired during the first six fractions were used to generate an average prostate clinical target volume (AV-CTV), and average rectum (AV-Rect). Using these structures, a new treatment plan was generated with a 7-mm PTV margin. Weekly CBCT scans were used to monitor the CTV coverage. A diet and mild laxatives were introduced to improve image quality and reduce prostate motion.
Twenty patients were treated with conform ART protocol. For these patients, 91% of the CBCT scans could be used to calculate the AV-CTV and AV-Rect. In 96% of the follow-up CBCT scans, the CTV was located within the average PTV. In the remaining 4%, the prostate extended the PTV by a maximum of 1 mm. Systematic and random errors for organ motion were reduced by a factor of two compared with historical data without diet and laxatives. An average PTV reduction of 29% was achieved. The volume of the AV-Rect that received >65 Gy was reduced by 19%. The mean dose to the anal wall was reduced on average by 4.8 Gy.
We safely reduced the high-dose region by 29%. The reduction in irradiated volume led to a significant reduction in the dose to the rectum. The diet and laxatives improved the image quality and tended to reduce prostate motion.
评估使用千伏级锥形束计算机断层扫描（CBCT）结合饮食和轻度泻药的离线自适应放射治疗（ART）方案对前列腺癌的首批临床结果。
23例患者开始治疗时计划靶体积（PTV）边缘为10毫米。在前六个分次期间采集的CBCT扫描用于生成平均前列腺临床靶体积（AV-CTV）和平均直肠（AV-Rect）。使用这些结构，生成了一个PTV边缘为7毫米的新治疗计划。每周进行CBCT扫描以监测CTV覆盖情况。引入饮食和轻度泻药以改善图像质量并减少前列腺运动。
20例患者接受了适形ART方案治疗。对于这些患者，91% 的CBCT扫描可用于计算AV-CTV和AV-Rect。在96% 的后续CBCT扫描中，CTV位于平均PTV内。在其余4% 的扫描中，前列腺最多超出PTV 1毫米。与未采用饮食和泻药的历史数据相比，器官运动的系统误差和随机误差降低了一半。平均PTV减少了29%。接受>65 Gy照射的AV-Rect体积减少了19%。肛门壁的平均剂量平均降低了4.8 Gy。
我们安全地将高剂量区域减少了29%。照射体积的减少导致直肠剂量显著降低。饮食和泻药改善了图像质量，并倾向于减少前列腺运动。
