目的 介绍了一种用半导体电离室测量多排CT辐射剂量的原理和方法,为完善我国现有医疗CT检测规范提供技术信息.方法 通过介绍X射线辐射剂量计Barracuda的测量原理和多排CT辐射剂量测量的参数设置依据,并结合在Philip Brilliance iCT 256机器上的应用实例,阐述了用半导体电离室的探测器测量多排CT辐射剂量的关键技术.结果 基于CT扫描参数合理设置探测器参数后,多排CT辐射剂量空间分布情况得以较好展示.100 mm长杆空气电离室的测量范围远小于多排CT线束覆盖范围,需要对多排CT辐射剂量测量方法和技术进行更新.结论 新型探测器有利于揭示多排CT辐射剂量的特性规律.%Objective A mechanism and method of multi-detector or multi-slice CT dosimetry based on semi-conductor slice ionization chamber was introduced to provide technical information for the existing medical CT inspection criterion in China. Methods Through the introduction of X-ray dosimeter Barracuda' s detection principle, the basis of relevant parameter setting, and the application examples of Philip Brillinace iCT 256, the key technologies of multi-slice CT dosimetry was expounded. Results The spatial distribution of CT radiation dosage could be illustrated well by the detector with the slice ionization chamber after proper parameter setting. A pencil ionization chamber with a length of 100 mm was not sufficient to cover the irradiating range by X-ray beam of multi-slice CT, which was expected to renew the detection technology of radiation dosage for multi-slice CT. Conclusions This new detector is helpful to reveal the characteristics of the radiation dosage regularity in multi-slice CT.
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