Uncertainties in CT-based radiation therapy treatment planning associated with patient breathing
Uncertainties in CT-based radiation therapy treatment planning associated with patient breathing
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DOI：
10.1016/s0360-3016(96)00275-1
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发表时间：
1996-08-01
影响因子：
7
通讯作者：
Robertson, JM
中科院分区：
文献类型：
--
作者：
Balter, JM;TenHaken, RK;Robertson, JM
目的：评估与患者自由呼吸时获得的治疗计划计算机断层扫描 (CT) 数据相关的不确定性。方法和材料：胸部或腹部肿瘤患者在安静、自由呼吸时接受标准治疗计划 CT 研究，然后在正常吸气和正常呼气时屏住呼吸进行 CT 扫描。每位患者的所有三个 CT 数据集上的相同治疗计划指出了以下方面的差异：（a）辐射路径长度； (b) 机关的职位； (c) 肺、肝和肾的物理体积； (d) 计划评估工具的解释，例如剂量体积直方图和正常组织并发症概率（NTCP）模型；结果：吸气和呼气数据在辐射路径长度方面存在差异（近四分之一的病例路径长度差异 >1 厘米），尽管自由呼吸和平均路径长度没有表现出较大差异（0-9 毫米），肝脏和肾脏运动平均为 2 厘米，而自由呼吸和平均位置之间的差异平均为 0.6 厘米，肝脏的物理体积自由呼吸和静态研究之间的差异高达 12%，对于剂量，呼气和吸气研究的 NTCP 计算从 3% 到 43% 不等，导致自由呼吸研究的 NTCP 为 15%。 结论：自由呼吸 CT 研究可能不正确地估计关键结构的位置和体积，因此可能会误导基于此类体积依赖标准（例如剂量体积直方图和 NTCP 计算）的计划评估。
Purpose: To evaluate uncertainties associated with treatment-planning computed tomography (CT) data obtained with the patient breathing freely.Methods and Materials: Patients with thoracic or abdominal tumors underwent a standard treatment-planning CT study while breathing quietly and freely, followed by CT scans while holding their breath at normal inhalation and normal exhalation, Identical treatment plans on all three CT data sets for each patient pointed out differences in: (a) radiation path lengths; (b) positions of the organs; (c) physical volumes of the lung, liver, and kidneys; (d) the interpretation of plan evaluation tools such as dose-volume histograms and normal tissue complication probability (NTCP) models; and (e) how well the planning CT data set represented the average of the inhalation and exhalation studies.Results: Inhalation and exhalation data differ in terms of radiation path length (nearly one quarter of the cases had path-length differences >1 cm), although the free breathing and average path lengths do not exhibit large differences (0-9 mm), Liver and kidney movements averaged 2 cm, whereas differences between the free breathing and average positions averaged 0.6 cm, The physical volume of the liver between the free breathing and static studies varied by as much as 12%, The NTCP calculations on exhale and inhale studies varied from 3 to 43% for doses that resulted in a 15% NTCP on the free-breathing studies.Conclusion: Free-breathing CT studies may improperly estimate the position and volume of critical structures, and thus may mislead evaluation of plans based on such volume dependent criteria such as dose-volume histograms and NTCP calculations.