Simultaneous integrated protection A new concept for high-precision radiation therapy
Simultaneous integrated protection A new concept for high-precision radiation therapy
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DOI：
10.1007/s00066-016-1057-x
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发表时间：
2016-12-01
影响因子：
3.1
通讯作者：
Grosu, Anca-Ligia
中科院分区：
文献类型：
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作者：
Brunner, Thomas B.;Nestle, Ursula;Grosu, Anca-Ligia
目的立体定向放射治疗临近危及器官（OAR）需要特别注意。一种新的调强放射治疗（IMRT）处方的概念，称为同步综合保护（SIP）的可量化的和可比的剂量处方的目标非常接近OARdetails.Materials和方法定义的保护体积（PTVSIP）的规划风险体积（PRV）与总规划目标体积（PTV）的交叉体积。PTV的其余部分代表占主导地位的PTV（PTVdom）。使用IMRT进行计划。根据ICRU，PTVdom的处方剂量分为3、5、8或12个部分。对OAR的限制表示为绝对剂量和2戈伊的等效剂量（EQD 2）。对OAR的总风险量的剂量是尊重限制。违反OAR的约束条件触发了计划迭代，增加了分割。结果6例OAR为大气道（n = 2）或肠道（n = 4）的患者，分别应用SIP 3次、5次、8次和12次，分别为1例、3例、1例和1例。PTV为14.5-84.9 ml，PTVSIP为1.8-3.9 ml（PTV的2.9- 13.4%）。根据绝对剂量-体积直方图（剂量/ml）分析计划的安全性。通过比较PRV的剂量限制与OAR的剂量限制，可以确定剂量下降的陡度（Wilcoxon检验p = 0.001）。相应的OAR的限制得到了尊重。结论SIP治疗PTV的中位剂量>= 100%，可达到高的局部控制率和低的毒副反应。需要更长时间的随访来验证结果，目前正在进行一项前瞻性临床试验，以测试这种新方法在胸部和腹部立体定向体部放射治疗中的作用。
Objective Stereotactic radiotherapy near serial organs at risk (OAR) requires special caution. A novel intensity-modulated radiotherapy (IMRT) prescription concept termed simultaneous integrated protection (SIP) for quantifiable and comparable dose prescription to targets very close to OAR is described.Materials and methods An intersection volume of a planning risk volume (PRV) with the total planning target volume (PTV) defined the protection volume (PTVSIP). The remainder of the PTV represented the dominant PTV (PTVdom). Planning was performed using IMRT. Dose was prescribed to PTVdom according to ICRU in 3, 5, 8, or 12 fractions. Constraints to OARs were expressed as absolute and as equieffective doses at 2 Gy (EQD2). Dose to the gross risk volume of an OAR was to respect constraints. Violation of constraints to OAR triggered a planning iteration at increased fractionation. Dose to PTVSIP was required to be as high as possible within the constraints to avoid local relapse.Results SIP was applied in 6 patients with OAR being large airways (n = 2) or bowel (n = 4) in 3, 5, 8, and 12 fractions in 1, 3, 1, and 1 patients, respectively. PTVs were 14.5-84.9 ml and PTVSIP 1.8-3.9 ml (2.9-13.4 % of PTV). Safety of the plans was analyzed from the absolute dose-volume histogram (dose to ml). The steepness of dose fall-off could be determined by comparing the dose constraints to the PRVs with those to the OARs (Wilcoxon test p = 0.001). Constraints were respected for the corresponding OARs. All patients had local control at a median 9 month follow-up and toxicity was low.Conclusion SIP results in a median dose of >= 100 % to PTV, to achieve high local control and low toxicity. Longer follow-up is required to verify results and a prospective clinical trial is currently testing this new approach in chest and abdomen stereotactic body radiotherapy.