Kobayashi Tsuyoshi, Koyama Tomomi, Terada Masami, Negishi Toru
Medical Safety Section, Medical Policy Division, Bureau of Social Welfare and Public Health, Tokyo Metropolitan Government.
Department of Radiology, St Luke's International Hospital.
Nihon Hoshasen Gijutsu Gakkai Zasshi. 2023 Nov 20;79(11):1266-1273. doi: 10.6009/jjrt.2023-1406. Epub 2023 Oct 2.
The average glandular dose (AGD) is very important in the quality control of mammography. The AGD calculation requires measurements of half-value layer (HVL) and entrance surface air karma (ESAK). The HVL is measured by the Al-attenuation method using a non-energy-dependent ionization dosimeter. As the Al-attenuation method performs measurements using a succession of added filters, it requires lots of X-ray exposure and measurement time. In recent years, measuring instruments that can measure tube voltage, irradiation time, exposure dose, HVL, and other factors, at the same time, using one shot of X-rays have been developed. In this study, measurement of the AGD using multiparameter X-ray measuring instrument about rhodium (Rh) and tungsten (W) anode X-ray tubes. A comparative study was performed using standard ionization dosimeters. The error in measurements was as follows: HVL 5.8%, ESAK 3.3%, and AGD 2.9%. The AGD measurement using a multiparameter X-ray measuring instrument is simple and can significantly reduce the measurement time while maintaining accuracy.
平均腺体剂量(AGD)在乳腺X线摄影的质量控制中非常重要。AGD的计算需要测量半值层(HVL)和入射表面空气比释动能(ESAK)。HVL采用非能量依赖型电离剂量计通过铝衰减法测量。由于铝衰减法使用一系列添加的滤过器进行测量,因此需要大量的X射线曝光和测量时间。近年来,已开发出能够通过单次X射线同时测量管电压、照射时间、曝光剂量、HVL和其他因素的测量仪器。在本研究中,使用多参数X射线测量仪器对铑(Rh)和钨(W)阳极X射线管的AGD进行测量。使用标准电离剂量计进行了一项对比研究。测量误差如下:HVL为5.8%,ESAK为3.3%,AGD为2.9%。使用多参数X射线测量仪器进行AGD测量很简单,并且在保持准确性的同时可以显著减少测量时间。