【摘要】 目的　用染色体畸变分析法对某钴源事故受照者进行了生物剂量估算和细胞遗传学的动态观察。方法　用本室细胞培养制片法略加改进 ,用泊松分布检验受照者的照射状况。结果　根据照后 11d“双 +环”频率推算“天”和“旺”的生物剂量分别为 2 .41和 2 .17Gy ,该剂量与物理剂量和临床诊断是相吻合的。“双 +环”的变化 ,随时间推移而下降 ,到 2a时 ,仍高于本底水平。结论　染色体畸变分析是估算受照剂量的理想方法更多还原

【Abstract】 Objective The effects of pitch,collimation and table speed on radiation dose to patient were studied.Methods The TLDs and a standard CT head dosimetry phantom were used for radiation dose measurements.All data were acquired on the third-generation scanner (Somatom plus 4,Siemens).The study was carried out at 10,8,5 mm collimation for pitches of 0.5,1,1.5,2.Table speed was 5,8,10,12,15,16 mm/1.5s.Results The average radiation dose at central hole and that at peripheral were measured.Results As the tube voltage and the round speed is given the radiation dose increases with increase in tube current and collimation,decreases with the table speed and pitch.The radiation dose at central hole was nearly equal to that at peripheral hole.There was no significant difference between them with statistical test.Conclusion As the tube voltage,tube current,round speed is given the average dose at central hole and that at peripheral hole are inverse proportional to pitch.The collimation less affected on the radiation dose in this study.更多还原