Malicki J
Greatpoland Cancer Centre, Poznan, Poland.
Strahlenther Onkol. 1999 May;175(5):208-12. doi: 10.1007/BF02742397.
The aim of this work was to estimate the error in dose calculations, to check the agreement between the measured and calculated doses and to analyse dose discrepancies in the group of patients undergoing total body irradiation.
A combination of lateral and anterior-posterior fields was used in 8 fractions and on 4 consecutive days. Doses were preliminarily calculated and then measured in vivo by thermoluminescent, semiconductor and ionization dosimeters attached to the body in 10 representative transverse cross-sections. Calculations and measurements were carried out for the beam at the body entry and exit. The error in dose calculations was estimated for each reference point. Dose deviations between calculations and measurements were analysed using the Student's t-test.
The error in preliminary dose calculations ranged from 3% to 15% (Table 1). Standard deviations of the measurements and percent deviations from the calculations exceeded 10% only for the lung and neck exits (Table 3). Average thermoluminescent readings were 6% higher than the corresponding semiconductor readings. The measured doses fitted the calculated values within the limit of error, except for the lung, head and neck exits for the whole group, depending on the type of fields used (Table 4).
本研究旨在评估剂量计算中的误差，检验测量剂量与计算剂量之间的一致性，并分析接受全身照射的患者组中的剂量差异。
采用前后野和侧野相结合的方式，分8次在连续4天内进行照射。剂量先进行初步计算，然后通过分别贴于身体10个代表性横断面的热释光剂量计、半导体剂量计和电离室剂量计在体内进行测量。在射野的体表入口处和出口处进行计算和测量。对每个参考点估算剂量计算误差。采用Student's t检验分析计算剂量与测量剂量之间的偏差。
初步剂量计算误差范围为3%至15%（表1）。仅在肺部和颈部出口处，测量值的标准差和相对于计算值的百分比偏差超过了10%（表3）。热释光剂量计的平均读数比相应的半导体剂量计读数高6%。除了整个组的肺部、头部和颈部出口处，根据所使用射野的类型，测量剂量在误差范围内符合计算值（表4）。
