Department of Radiation Oncology, Beckman Research Institute, City of Hope, Duarte, USA; Department of Radiation Oncology, University of Minnesota, Minneapolis, USA.
Deparment of Medical Imaging and Radiation Sciences, IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
Radiother Oncol. 2019 Dec;141:275-282. doi: 10.1016/j.radonc.2019.07.010. Epub 2019 Aug 14.
Total marrow irradiation (TMI) is a highly conformal treatment of the human skeleton structure requiring a high degree of precision and accuracy for treatment delivery. Although many centers worldwide initiated clinical studies using TMI, currently there is no standard for pretreatment patient setup. To this end, the accuracy of different patient setups was measured using pretreatment imaging. Their impact on dose delivery was assessed for multiple institutions.
Whole body imaging (WBI) or partial body imaging (PBI) was performed using pretreatment megavoltage computed tomography (MVCT) in a helical Tomotherapy machine. Rigid registration of MVCT and planning kilovoltage computed tomography images were performed to measure setup error and its effect on dose distribution. The entire skeleton was considered the planning target volume (PTV) with five sub regions: head/neck (HN), spine, shoulder and clavicle (SC), and one avoidance structure, the lungs. Sixty-eight total patients (>300 images) across six institutions were analyzed.
Patient setup techniques differed between centers, creating variations in dose delivery. Registration accuracy varied by anatomical region and by imaging technique, with the lowest to the highest degree of pretreatment rigid shifts in the following order: spine, pelvis, HN, SC, and lungs. Mean fractional dose was affected in regions of high registration mismatch, in particular the lungs.
MVCT imaging and whole body patient immobilization was essential for assessing treatment setup, allowing for the complete analysis of 3D dose distribution in the PTV and lungs (or avoidance structures).
全骨髓照射（TMI）是一种高度适形的人体骨骼结构治疗方法，需要高度精确和准确的治疗输送。尽管世界上许多中心都开始了使用 TMI 的临床研究，但目前还没有预处理患者设置的标准。为此，使用预处理成像测量了不同患者设置的准确性。评估了多个机构的剂量输送的影响。
全身成像（WBI）或部分身体成像（PBI）使用螺旋断层放疗机中的预处理兆伏 CT（MVCT）进行。MVCT 和计划千伏 CT 图像的刚性配准用于测量设置误差及其对剂量分布的影响。整个骨骼被视为计划靶区（PTV），有五个亚区：头/颈（HN）、脊柱、肩部和锁骨（SC）和一个避免结构，肺部。六个机构的 68 名患者（超过 300 张图像）进行了分析。
中心之间的患者设置技术不同，导致剂量输送存在差异。注册准确性因解剖区域和成像技术而异，预处理刚性移位的程度从低到高依次为：脊柱、骨盆、HN、SC 和肺部。在注册不匹配程度较高的区域，特别是肺部，会影响平均分数剂量。
MVCT 成像和全身患者固定对于评估治疗设置至关重要，允许对 PTV 和肺部（或避免结构）中的完整 3D 剂量分布进行分析。
