加强对CT检查患者辐射剂量的管理

Enhance the management of radioactive dose received by patients examined by CT

目的研究CT机普通扫描方式和单层螺旋扫描方式的患者体表X线吸收量,探讨CT检查时患者辐射剂量的推荐值。方法前瞻性选取普通扫描方式10例固定管电压为130kV,变换管电流、层厚、层数进行不同部位的扫描。扫描前根据解剖结构,在扫描范围中心的前后分别布点,每个点置入3个探测元件TLF(Mg,Cu,P),用热释光方法(TLD)读出数值,进行处理;单层螺旋普通扫描方式30例,管电压、管电流等的组合与普通CT机相同,采用CT机自测值,记录之;再以不同的螺距和扫描持续时间进行扫描,记录剂量值,对照、处理。结果普通扫描时,管电压、管电流一定,辐射剂量与层数成正比;螺旋扫描时,管电压、管电流和扫描长度一定,辐射剂量与扫描持续时间成正比,层厚、层数对辐射剂量的影响不大。结论优化扫描方案,可控制CT检查患者的辐射剂量。

Objective To study the received dose of X - ray of body surface in the two different ways that are ordinary scan and SCT, and investigate recommended received dose of patients. Methods Ten subjects were selected prospectively in ordinary scan way of CT, and the voltage of pipe was fixed on 130 kV. Different positions were scanned by various electricity of pipes, thickness and numbers of sheets. According to the structure of dissection points in which three TLF （Mg,Cu,P） were put placed, then read the data in TLD and dealed with them. Similarly, 30 subjects were chosen in the ordinary scan way of SCT. The received dose was read by CT machine which had the function that the dose could be measured automatically. Then the data was recorded, contrasted and handled. And another group of dose was got by scanning in different pith and lasting times, then was compared and dealed with. Results In SEQ, the received dose was positively correlated with numbers of layers when voltage and electricity of pipe were fixed. In SPI, the dose was positively connected with the lasting time of scan, but was little influenced by thickness and numbers of layers. Conclusion The radioactive dose of patients received can be controlled if the programme of scan is preferable.