监测受检者入射体表剂量的热释光方法的质量保证

Quality Assurance for Using Thermoluminescence Dosimetry to Monitor the Entrance Surface Doses of Examinees Undergoing X-ray Diagnoses

[目的]为保证医疗照射剂量监测结果的可靠性,开展热释光剂量(thermoluminescence dosimetry,TLD)方法的质量保证研究。[方法]在次级标准剂量学实验室进行TLD的分散性、剂量线性和能量响应特性实验;通过建立标准化退火和测量程序并对设备进行定期校正来控制监测质量。[结果]经分档后各档TLD的灵敏度差异<4%;在0.3～20mGy的剂量范围内,所用TLD具有理想的剂量线性(R^2=0.9999);在医用诊断X射线常见的能量范围内,所用TLD的能量响应变化<1.0%;盲样测量结果表明,TLD的测量值与约定真值偏差在-2.55%～0.12%之间。[结论]通过加强TLD的质量保证,可以有效提高X射线诊断受检者入射体表剂量监测结果的可比性和准确性。

[ Objective ] The study on quality assurance of thermoluminescence dosimetry（ TLD ）was carried out to ensure the reliability of dose monitoring. [ Methods ] Experiments for studying the sensitivity dispersion, dose linearity and energy response of the TLDs were performed in a secondary standard dosimetry laboratory. Standardized procedures for the annealing and measurements as well as the regular calibration of the equipments were established to control the monitoring quality. [ Results ] Having been grouped, the sensitivity dispersion of the TLDs in each group was less than 4%. The dose linearity of the TLDs was ideal in a dose range of 0.3-20mGy. The TLD response changed less than 1.0% in the general energy range of medical diagnostic X-rays. Blinding tests showed that the dose deviation between the TLD measurements and the reference values varied from -2.55% to 0.12%. [ Conclusion ] The quality assurance measures established in this study can ensure the accuracy of monitored doses.