Zare Mahkameh, Lashkari Marzieh, Ghalehtaki Reza, Ghasemi Arash, Dehghan Manshadi Hamidreza, Mir Ali, Noorollahi Somayeh, Alamolhoda Mahboobeh
Department of Radiation Oncology, Hafte-e-Tir Hospital, Iran University of Medical Sciences, Shar e Rey, Tehran, Iran.
Department of Radiation Oncology, Radiation Oncology Research Center, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
Med Dosim. 2016;41(4):296-299. doi: 10.1016/j.meddos.2016.06.008. Epub 2016 Sep 10.
External radiotherapy is a standard treatment procedure for localized prostate cancer. Given the relatively high long term survival treatment complications have been brought in center of attention. In this planning study, between 2012 and 2014, CT simulation data of 90 consecutive high-risk prostate cancer patients were collected. In the first phase, all were planned for whole pelvis irradiation up to 46Gy in 23 daily fractions. In the second phase, only the prostate gland was the target of radiation. Next, the subjects were divided randomly into three groups and each received a unique 5field conformal radiation plan including Plan A (Gantry angle: 0, 60, 120, 240, and 300), Plan B (Gantry angles: 0, 90, 120, 240, and 270) and Plan C (Gantry angles: 0, 60, 90, 270, and 300). The total dose was 70Gy. For each patient, the rectum, bladder, and both femoral heads were contoured as the at risk organs (OAR). From dose volume histograms, the proportional dose of PTV V100, the bladder and rectum V80 and V90 and femoral head V50 and V100 were calculated in all subjects and compared across plans. A statistically significant difference in the femoral head V50 and V100 was found between our studied 5field plans so that in Plan A (beam angles: 0, 60, 120, 240 and 300) less dose was received by both heads of femur. This study suggests that 5 field treatment planning including an anterior, two anterior oblique and two posterior oblique portals to be more proper for 3D conformal radiotherapy in order to spare femoral head with acceptable PTV coverage, and bladder and rectal doses.
外照射放疗是局限性前列腺癌的标准治疗方法。鉴于长期生存率相对较高，治疗并发症已成为关注焦点。在本规划研究中，于2012年至2014年收集了90例连续的高危前列腺癌患者的CT模拟数据。在第一阶段，所有患者均计划进行全盆腔照射，剂量达46Gy，分23次每日照射。在第二阶段，仅前列腺为放疗靶区。接下来，将受试者随机分为三组，每组接受独特的5野适形放疗计划，包括计划A（机架角度：0、60、120、240和300）、计划B（机架角度：0、90、120、240和270）和计划C（机架角度：0、60、90、270和300）。总剂量为70Gy。对于每位患者，将直肠、膀胱和双侧股骨头勾勒为危及器官（OAR）。从剂量体积直方图中，计算所有受试者的PTV V100、膀胱和直肠V80和V90以及股骨头V50和V100的比例剂量，并在各计划之间进行比较。在我们研究的5野计划之间，发现股骨头V50和V100存在统计学显著差异，以至于在计划A（射束角度：0、60、120、240和300）中，双侧股骨头接受的剂量较少。本研究表明，包括一个前野、两个前斜野和两个后斜野的5野治疗计划更适合三维适形放疗，以便在保证PTV覆盖可接受的情况下，保护股骨头以及膀胱和直肠的剂量。
