Department of Radiation Oncology, Rush University Medical Center, Chicago, IL 60612, USA.
Med Phys. 2012 Apr;39(4):2239-48. doi: 10.1118/1.3697526.
Total body irradiation (TBI) with megavoltage photon beams has been accepted as an important component of management for a number of hematologic malignancies, generally as part of bone marrow conditioning regimens. The purpose of this paper is to present and discuss the authors' TBI technique, which both simplifies the treatment process and improves the treatment quality.
An AP/PA TBI treatment technique to produce uniform dose distributions using sequential collimator reductions during each fraction was implemented, and a sample calculation worksheet is presented. Using this methodology, the dosimetric characteristics of both 6 and 18 MV photon beams, including lung dose under cerrobend blocks was investigated. A method of estimating midplane lung doses based on measured entrance and exit doses was proposed, and the estimated results were compared with measurements.
Whole body midplane dose uniformity of ±10% was achieved with no more than two collimator-based beam modulations. The proposed model predicted midplane lung doses 5% to 10% higher than the measured doses for 6 and 18 MV beams. The estimated total midplane doses were within ±5% of the prescribed midplane dose on average except for the lungs where the doses were 6% to 10% lower than the prescribed dose on average.
The proposed TBI technique can achieve dose uniformity within ±10%. This technique is easy to implement and does not require complicated dosimetry and/or compensators.
全身照射（TBI）与兆伏级光子束已被接受为许多血液恶性肿瘤治疗的重要组成部分，通常作为骨髓预处理方案的一部分。本文旨在介绍和讨论作者的 TBI 技术，该技术既简化了治疗过程，又提高了治疗质量。
采用 AP/PA 全身照射治疗技术，在每次分次照射中通过顺序准直器缩小来产生均匀的剂量分布，并提供了一个示例计算工作表。使用这种方法，研究了 6 和 18 MV 光子束的剂量学特性，包括在 Cerrobend 块下的肺剂量。提出了一种基于测量的入射剂量和出射剂量来估算中平面肺剂量的方法，并将估算结果与测量结果进行了比较。
通过不超过两次准直器调制，实现了全身中平面剂量均匀性 ±10%。对于 6 和 18 MV 射线，所提出的模型预测的中平面肺剂量比测量值高 5%至 10%。除了肺部的剂量比规定的中平面剂量平均低 6%至 10%外，估算的总中平面剂量平均在规定的中平面剂量的±5%以内。
所提出的 TBI 技术可以实现剂量均匀性在 ±10%以内。该技术易于实施，不需要复杂的剂量学和/或补偿器。
