头部CT扫描受检者敏感器官体表辐射量及防护措施的初步研究

目的 探讨CT在头部扫描时，受检者在不同防护措施下敏感器官体表部位的辐射剂量，为头颅CT扫描时防护用品的应用提供科学的依据。方法 采用第一代双源CT对标准人体模型在未加任何防护（A组）、戴铅围脖盖铅衣（B组）和戴铅围脖穿上无袖铅衣（C组）三种方式下进行头部常规（head routine sequence）序列扫描。在体模敏感器官体表布置热释光剂量计（TLD），测量各处的辐射剂量。曝光后所有TLD进行测量处理和统计分析。结果 CT扫描后剂量参数显示A、B、C组的容积CT剂量指数（CTDLvol）均为44.06 mGy，剂量长度乘积（DLP）均为634 mGy·cm。TLD测量显示A、B、C组直接照射部位的辐射剂量差异无统计学意义（P=0.712）；颈部铅围脖防护区A、B、C组的辐射均值分别为（2.57±0.65） mGy，（2.30±1.10 ） mGy和（2.48±0.90 ） mGy，各组之间辐射剂量差异无统计学意义（P=0.816）。体部腹侧区A组辐射剂量〔（0.66±0.37） mGy〕高于防护后的B组〔（0.18±0.18） mGy〕和C组〔（ 0.18±0.16） mGy〕,P均PB组〔(0.28±0.22) mGy〕>C组〔(0.14±0.12) mGy〕,P<0.05。结论 双源CT头部扫描时，铅围脖加穿上铅衣的方式较传统铅衣覆盖方法可明显降低患者非受检部位敏感器官的X光辐射剂量。

Radiation Dose of Body Surface at Sensitive Organs and Its Protective Precaution in Head CT Scanning:

Objective To investigate the radiation dose of body surface at sensitive organs using different protective precaution in head CT scanning. Methods The standard phantom received head routine sequence scanning with dual-source computed tomography. The phantoms were scanned with three different protective precaution: group A (without protective clothing), group B (wearing lead collar and cover lead clothes), group C (wearing lead collar and clothes without cuffs). The thermoluminescence dosimeters (TLD) was placed on the body surface corresponding to sensitive organs to measure radiation dose. Results The volume of CT dose index (CTDIvol) and dose length product (DLP) in group A, B and C were same, 44.06 mGy and 634 mGy·cm, respectively. There was no statistic significant difference between group A, B and C of radiation dose in non-protective region (P=0.712). The radiation dose in the neck region under the cover of lead collar in group A, B and C were (2.57 ± 0.65) mGy, (2.30 ± 1.10) mGy and (2.48 ± 0.90) mGy, respectively, without statistic significant difference between groups (P=0.816). However, the radiation dose in abdominal region of group A was (0.66±0.37) mGy, which was significantly higher than that of group B 〔(0.18 ± 0.18) mGy〕 and group C 〔(0.18±0.16) mGy〕, The radiation dose in dorsal region of group A was (0.55±0.43) mGy, which was significantly higher than that of group B 〔(0.28±0.22) mGy〕, while that of group C 〔(0.14±0.12) mGy〕 was significantly lower than group B. Conclusion Compared to traditional lead coverage, lead collar and cloth can decrease the radiation dose of body surface and sensitive organs in head scan with dual source CT.