Comparison of three radiotherapy treatment planning protocols of definitive external-beam radiation for localized prostate cancer.
Comparison of three radiotherapy treatment planning protocols of definitive external-beam radiation for localized prostate cancer.
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DOI：
10.1007/s10147-005-0519-4
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发表时间：
2005-12-01
影响因子：
3.3
通讯作者：
Hiraoka, Masahiro
中科院分区：
文献类型：
--
作者：
Zhu, SuYu;Mizowaki, Takashi;Hiraoka, Masahiro
背景技术背景：比较了京都大学设计和临床应用的三种针对局限性前列腺癌的确定性外束放射治疗计划（RTTP）方案。根据三种不同的RTTP方案创建治疗计划（旧的三维适形放射治疗[3D-CRT]，新的3D-CRT，和调强放射治疗[IMRT]）对5名局限性前列腺癌患者的计算机断层扫描（CT）数据集的影响。3D-CRT方案采用动态弧形适形技术。剂量分布的差异进行了评估和比较的基础上剂量体积直方图（DVH）analysis.RESULTS：临床靶体积（=前列腺单独）的覆盖范围是可比的三个RTTP协议。然而，接受至少95%处方剂量的体积百分比（V95）、处方剂量覆盖95%体积的百分比（D95）和计划靶体积的符合性指数（PTV）的平均值对于IMRT为99%、97%和0.88，对于新的3D-CRT为93.9%、94.5%和0.76;而旧3D-CRT方案分别为59.6%、82.9%和0.6。IMRT方案的PTV剂量不均匀性大于新3D-CRT方案。直肠壁和膀胱壁的剂量与新的3D-CRT和IMRT方案几乎相当，但与旧的3D-CRT方案相比，由于最低处方剂量和PTV的不完全剂量覆盖，旧的3D-CRT方案较低。结论：旧的3D-CRT方案不能达到IMRT方案中PTV设置的目标。新的3D-CRT和IMRT方案在PTV覆盖范围和正常组织保留方面基本相当，尽管IMRT方案实现了PTV的最适形剂量分布，以换取更大但可接受的剂量不均匀性。
BACKGROUND: Three radiotherapy treatment planning (RTTP) protocols for definitive external-beam radiation for localized prostate cancer, designed and clinically applied at Kyoto University, were compared.METHODS: Treatment plans were created according to three different RTTP protocols (old three-dimensional conformal radiotherapy [3D-CRT], new 3D-CRT, and intensity-modulated radiotherapy [IMRT]) on computed tomography (CT) data sets of five patients with localized prostate cancer. The dynamic-arc conformal technique was used in the 3D-CRT protocols. Differences in dose distribution were evaluated and compared based on dose-volume histogram (DVH) analyses.RESULTS: The coverage of the clinical target volume (= prostate alone) was comparable among the three RTTP protocols. However, the average values for the percent volume that received at least 95% of the prescription dose (V95), the percent of the prescription dose covering 95% of the volume (D95), and the conformity index of the planning target volume (PTV) were 99%, 97%, and 0.88 for the IMRT; 93.9%, 94.5%, and 0.76 for the new 3D-CRT; and 59.6%, 82.9%, and 0.6 for the old 3D-CRT protocol, respectively. Inhomogeneity of doses to the PTV was larger with the IMRT protocol than with the new 3D-CRT protocol. Doses to both the rectal wall and bladder wall were almost comparable with the new 3D-CRT and IMRT protocols, but were lower with the old 3D-CRT protocol, due to the lowest prescription dose and incomplete dose coverage of the PTV.CONCLUSION: The old 3D-CRT protocol could not achieve the goals for the PTV set in the IMRT protocol. The new 3D-CRT and IMRT protocols were generally comparable in terms of both the PTV coverage and normal tissue-sparing, although the IMRT protocol achieved the most conformal dose distribution to the PTV, in return for a larger, but acceptable, dose inhomogeneity.