自制TOMO模体与Cheese模体在螺旋断层放疗系统剂量测量的比较研究

目的 本文通过自制TOMO模体与Cheese模体在TOMO中剂量测量的差异比较，初步验证自制TOMO模体用于临床的可行性。方法 在TOMO固定照射野下，模体中心轴上取5个不同测试深度，用A1SL型电离室及TomoElectrometer静电计分别测量各位置的电荷量，依据美国医学物理家协会（AAPM） TG-148号报告和TG-51号报告，计算相应位置的吸收剂量，并比较两种模体的剂量差异。结果 自制TOMO模体和Cheese模体中5个不同深度剂量的相对偏差分别为0.35%、0.3%、0.3%、0.34%和0.0%。结论 两种模体剂量测量相对偏差均小于0.35%，表明自制TOMO模体与Cheese模体在剂量性能上具有一致性，自制TOMO模体可用于TOMO的剂量测量。

Comparative study on dosimetry of homemade TOMO phantom and Cheese phantom in tomotherapy

Objective To preliminarily evaluate the feasibility of home-made TOMO phantom for clinical practice by comparing the difference in dose verification between the home-made TOMO phantom and the Cheese phantom of the Tomotherapy(TOMO) system. Methods Five different test depths were selected on the central axis of the phantom, and the charge amount at each position was measured by the A1SL ionization chamber and the Tomoelectrometer electrometer in the condition of TOMO fixed irradiation field. According to the American Association of Medical Physicists (AAPM) TG-148 report and TG-51 report, calculate the absorbed dose at the corresponding position, and compare the dose difference between the two phantoms. Results The relative deviations of the five different depth doses in the home-made TOMO phantom and the Cheese phantom were 0.35%, 0.3%, 0.3%, 0.34% and 0.0%, respectively. Conclusion The relative deviation of the two phantom dose measurements were less than 0.35%,which indicates that the home-made phantom and the Cheese phantom consistent in dose performance. The home-made TOMO phantom could be used for the dose measurement of TOMO.