Institute of Biostructures and Bioimages, National Council of Research (CNR), Via Pansini 5, 80131, Naples, Italy.
Radiat Oncol. 2010 May 11;5:33. doi: 10.1186/1748-717X-5-33.
This paper analyses normal tissue sparing capability of radiation treatment techniques in Hodgkin's lymphoma with large treatment volume.
10 patients with supradiaphragmatic Hodgkin's lymphoma and planning target volume (PTV) larger than 900 cm3 were evaluated. Two plans were simulated for each patient using 6 MV X-rays: a conventional multi-leaf (MLC) parallel-opposed (AP-PA) plan, and the same plan with additional MLC shaped segments (forward planned intensity modulated radiation therapy, FPIMRT). In order to compare plans, dose-volume histograms (DVHs) of PTV, lungs, heart, spinal cord, breast, and thyroid were analyzed. The Inhomogeneity Coefficient (IC), the PTV receiving 95% of the prescription dose (V95), the normal tissue complication probability (NTCP) and dose-volume parameters for the OARs were determined.
the PTV coverage was improved (mean V95AP-PA=95.9 and ICAP-PA=0.4 vs. V95FPIMRT=96.8 and ICFPIMRT=0.31, p<or=0.05) by the FPIMRT technique compared to the conventional one. At the same time, NTCPs of lung, spinal cord and thyroid, and the volume of lung and thyroid receiving>or=30 Gy resulted significantly reduced when using the FPIMRT technique.
The FPIMRT technique can represent a very useful and, at the same time, simple method for improving PTV conformity while saving critical organs when large fields are needed as in Hodgkin's lymphoma.
本文分析了大治疗体积霍奇金淋巴瘤放射治疗技术对正常组织的保护能力。
对 10 例膈上霍奇金淋巴瘤患者进行评估，其计划靶区（PTV）大于 900cm³。为每位患者模拟两种计划：6MV X 射线常规多叶准直器（MLC）平行对（AP-PA）计划和相同计划加额外 MLC 形状段（正向计划调强放射治疗，FPIMRT）。为了比较计划，分析了 PTV、肺、心脏、脊髓、乳腺和甲状腺的剂量-体积直方图（DVHs）。测定不均匀性系数（IC）、PTV 接受处方剂量 95%的体积（V95）、正常组织并发症概率（NTCP）和 OAR 剂量-体积参数。
与常规技术相比，FPIMRT 技术可改善 PTV 覆盖（AP-PA 时平均 V95=95.9 和 ICAP-PA=0.4，FPIMRT 时 V95=96.8 和 ICFPIMRT=0.31，p≤0.05）。同时，使用 FPIMRT 技术可显著降低肺、脊髓和甲状腺的 NTCP 以及肺和甲状腺接受>或=30Gy 的体积。
FPIMRT 技术可在大野照射如霍奇金淋巴瘤时提高 PTV 适形性，同时保护关键器官，是一种非常有用且简单的方法。
