Abstract Present study compares two different 3D radiotherapy techniques: three-dimensional conformal radiotherapy (3D-CRT) and 3D external-beam radiation dose fields from computerized treatment plans, produced for 30 prostate cancer patients. All of the patients were the subject of treatment at the National Cancer Institute in Egypt. Evaluation was made of dose homogeneity within the target volume and the dose to critical organs (organs at risk, OAR). The plans were based on CT scans, all for cases of localized prostate cancer (all stage T2N0M0), with the CT scans transferred to the treatment planning systems. Comparison of the two different 3D radiation techniques was made in terms of isodose distributions and dose-volume histograms. The percentage of the planning target volume receiving 95% (V95) and 107% (V107) of the prescribed dose were obtained. For the 3D-CRT technique, the mean values for these were respectively 90.6% and 5.7% while for the other 3D technique they were 94.9% and 3.8%. In examining the dose received by the OAR, use of the 3D-CRT technique was found to provide the preferred dose distribution, with much greater sparing of the bladder, rectum and head of both femora. For the rectum the mean V70, V75 and D95 values (the latter referring to doses to 95% of the treatment volume) for the 3D-CRT technique were 35.5%, 32.2% and 34% while for the other 3D technique these were 8.4%, 0.2% and 12% respectively. For the bladder, the mean V40 and V65 values obtained using the 3D-CRT technique were 80.8% and 74.9% while for the alternative 3D technique they were 20.4% and 17% respectively. Thus for the particular cohort, the 3D-CRT technique provided superior target coverage and reduction of dose to the OAR.

中文翻译：

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前列腺癌放疗的辐射剂量均匀性与关键器官

摘要 本研究比较了两种不同的 3D 放射治疗技术：三维适形放射治疗 (3D-CRT) 和来自计算机化治疗计划的 3D 外束辐射剂量场，为 30 名前列腺癌患者制作。所有患者都是埃及国家癌症研究所的治疗对象。评估目标体积内的剂量均匀性和关键器官（风险器官，OAR）的剂量。这些计划基于 CT 扫描，均针对局部前列腺癌（所有 T2N0M0 期），并将 CT 扫描传输到治疗计划系统。在等剂量分布和剂量体积直方图方面对两种不同的 3D 辐射技术进行了比较。获得了接受95% (V95) 和107% (V107) 规定剂量的计划目标体积的百分比。对于 3D-CRT 技术，这些平均值分别为 90.6% 和 5.7%，而对于其他 3D 技术，它们分别为 94.9% 和 3.8%。在检查 OAR 接受的剂量时，发现使用 3D-CRT 技术提供了首选的剂量分布，对膀胱、直肠和双股骨头的保护更大。对于直肠，3D-CRT 技术的平均 V70、V75 和 D95 值（后者指的是治疗体积的 95% 的剂量）为 35.5%、32.2% 和 34%，而对于其他 3D 技术，这些值为 8.4% 、0.2% 和 12%。对于膀胱，使用 3D-CRT 技术获得的平均 V40 和 V65 值为 80.8% 和 74.9%，而对于替代 3D 技术，它们是 20。分别为 4% 和 17%。因此，对于特定的队列，3D-CRT 技术提供了卓越的目标覆盖率和 OAR 剂量的减少。