使用 FDG-PET 引导的调强放疗推量治疗术后局部复发性直肠癌的焦点剂量升级：基于剂量体积直方图和 NTCP 比较的计划研究。
Focal dose escalation using FDG-PET-guided intensity-modulated radiation therapy boost for postoperative local recurrent rectal cancer: a planning study with comparison of DVH and NTCP.
机构信息
Department of Radiation Oncology, Tohoku University School of Medicine, Sendai, Japan.
出版信息
BMC Cancer. 2010 Apr 7;10:127. doi: 10.1186/1471-2407-10-127.
BACKGROUND
To evaluate the safety of focal dose escalation to regions with standardized uptake value (SUV) >2.0 using intensity-modulated radiation therapy (IMRT) by comparison of radiotherapy plans using dose-volume histograms (DVHs) and normal tissue complication probability (NTCP) for postoperative local recurrent rectal cancer
METHODS
First, we performed conventional radiotherapy with 40 Gy/20 fr. (CRT 40 Gy) for 12 patients with postoperative local recurrent rectal cancer, and then we performed FDG-PET/CT radiotherapy planning for those patients. We defined the regions with SUV > 2.0 as biological target volume (BTV) and made three boost plans for each patient: 1) CRT boost plan, 2) IMRT without dose-painting boost plan, and 3) IMRT with dose-painting boost plan. The total boost dose was 20 Gy. In IMRT with dose-painting boost plan, we increased the dose for BTV+5 mm by 30% of the prescribed dose. We added CRT boost plan to CRT 40 Gy (summed plan 1), IMRT without dose-painting boost plan to CRT 40 Gy (summed plan 2) and IMRT with dose-painting boost plan to CRT 40 Gy (summed plan 3), and we compared those plans using DVHs and NTCP.
RESULTS
D(mean) of PTV-PET and that of PTV-CT were 26.5 Gy and 21.3 Gy, respectively. V50 of small bowel PRV in summed plan 1 was significantly higher than those in other plans ((summed plan 1 vs. summed plan 2 vs. summed plan 3: 47.11 +/- 45.33 cm3 vs. 40.63 +/- 39.13 cm3 vs. 41.25 +/- 39.96 cm3 (p < 0.01, respectively)). There were no significant differences in V30, V40, V60, D(mean) or NTCP of small bowel PRV.
CONCLUSIONS
FDG-PET-guided IMRT can facilitate focal dose-escalation to regions with SUV above 2.0 for postoperative local recurrent rectal cancer.
背景
通过比较使用剂量-体积直方图（DVH）和正常组织并发症概率（NTCP）的放疗计划，评估使用调强放疗（IMRT）对标准化摄取值（SUV）>2.0 的区域进行焦点剂量递增的安全性，用于术后局部复发性直肠癌。
方法
首先，我们对 12 例术后局部复发性直肠癌患者进行 40 Gy/20 fr 的常规放疗（CRT 40 Gy），然后对这些患者进行 FDG-PET/CT 放疗计划。我们将 SUV>2.0 的区域定义为生物靶区（BTV），并为每位患者制定了三个增敏计划：1）CRT 增敏计划，2）无剂量绘画增敏计划的 IMRT，3）有剂量绘画增敏计划的 IMRT。总增敏剂量为 20 Gy。在有剂量绘画增敏计划的 IMRT 中，我们将 BTV+5 mm 的剂量增加到规定剂量的 30%。我们将 CRT 增敏计划添加到 CRT 40 Gy（总和计划 1）、无剂量绘画增敏计划的 IMRT 添加到 CRT 40 Gy（总和计划 2）和有剂量绘画增敏计划的 IMRT 添加到 CRT 40 Gy（总和计划 3），并使用 DVH 和 NTCP 比较这些计划。
结果
PTV-PET 的 D（mean）和 PTV-CT 的 D（mean）分别为 26.5 Gy 和 21.3 Gy。总和计划 1 中小肠 PRV 的 V50 明显高于其他计划（（总和计划 1 与总和计划 2 与总和计划 3：47.11 +/- 45.33 cm3 与 40.63 +/- 39.13 cm3 与 41.25 +/- 39.96 cm3（p<0.01，分别））。小肠 PRV 的 V30、V40、V60、D（mean）或 NTCP 无显著差异。
结论
FDG-PET 引导的 IMRT 可促进术后局部复发性直肠癌 SUV 高于 2.0 的区域进行焦点剂量递增。
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