妊娠期患者腹部CT检查所致胎儿辐射风险分析

目的：对妊娠患者进行常规腹部螺旋CT扫描所致胎儿辐射风险进行评估。方法：曝光条件由临床CT检查选择病例的统计数据确定。CT扫描仪包括3个生产厂商的双排、16排和64排CT。胎儿受照剂量由患者子宫的器官剂量代替。子宫器官剂量由SR250软件估算。结果：对于所有机型的常规腹部螺旋CT扫描,胎儿受照剂量范围为14～26mGy,平均值和方差为（18.5±4.7）mGy。结论：根据ICRP建议书,分别从3个角度评价胎儿辐射效应：①常规腹部螺旋CT扫描不会引起胎儿组织损伤及功能障碍;②不会造成胎儿智力发育障碍;③胎儿时期的X射线照射会提高幼儿时期癌症的发生率。然而,由于实际情况的复杂性,很难确定这个癌症发生率提高的程度有多大。因此,根据本次实验所估计的胎儿受照剂量,妊娠患者进行常规腹部螺旋CT扫描导致胎儿发生辐射效应的概率极低。

Estimation of fetal radiation risk to patients in abdomen routine CT scanning during pregnancy

Objective：To estimate the fetal radiation risk to pregnant women in standard abdomen CT examinations.Methods：Exposure parameters for the study were defined according to statistical dosimetry data on virtual clinical CT examinations of selected patient samples.CT scanners were classified by three manufacturers（GE Siemens and Phillips） and with different type（dual-slice 16-slice and 64-slice）.The radiation dose to the fetus was represented by the organ radiation dose of uterus which was estimated by SR250 Dosimetry.Results：For all abdomen CT examinations included in this study,the range of fetal radiation dose was from 14 to 26 mGy with average value of 18.5±4.7 mGy.Conclusion：According to ICRP publication,the radiation risk to the fetus has been analyzed from three aspects.Firstly,the risks of tissue injury and malformation would not be expected.Secondly,the risk of severe mental retardation is absent.The last effect is cancer risk.In-utero medical irradiation increases risks of childhood cancer of all types.However,particular uncertainties are too complicated to give assumptions to what extends the cancer risk would be increased.Therefore,the radiation effects to the fetus for pregnant women in standard abdomen CT examinations are very infrequent.