飞利浦iCT256轴扫剂量特性和剂量安全管理建议

A radiation feature study and dose safety management suggestion on Philips Multislice CT iCT 256 under axial scanning mode

目的验证iCT 256执行头部轴扫时辐射剂量机显值准确性,并探讨在该条件下辐射剂量安全管理方案。方法利用瑞典RTI公司的Solidose 400型辐射剂量计和中国计量科学研究院研制的T6M164型剂量体模（符合IEC 61223-2-6）,按头部轴扫条件重复三次测定剂量体模上5个钟点位的剂量值。结果①中心点CTDI100测量相对偏差在2%以内,而四周点位CTDI100测量相对偏差在20%以内;②CTDIvol实测值比机显值高5%16%;③单次头部轴扫有效剂量在0.863.63 mGy之间。结论中心点CTDI100的测量重复性好,外围四点位测量重复性差,且存在实测值略高于机显值的情况。应加强对患者累计辐射剂量的监管。

Objective To verify the reported CTDIvol value and explore dose safety managementprotocol of Philips Brilliance iCT 256 under axial scan mode with head protocolMethods A pencil dosimeter,Solidose 400 from Sweden RTI Electronics,is utilized to detect radiation dose index of phantom T6M1 64 (incompliance with IEC standard 61 223-2-6,provided by National Institute of Metrology of China)when scannedby iCT 256 under head axial protocolResults (1)Relative deviation of CTDI1 00 in the center point is about 2%and those in the peripheral 4 points are about 20% (2)Tested CTDIvol value is 5% ~1 6% greater thanreported value(3) Effective absorbing dose during one head axial scanning is about 086 mGy to 363mGyConclusions Accuracy of CTDI1 00 measurement in the center point is better than the peripheral fourpointsTested CTDIvol value might be greater than reported CTDIvol in certain conditions and supervision onaccumulated radiation dose of patient should be recommended.