高剂量CT辐射致家兔脾组织病理变化的初步实验研究

目的初步探讨CT腹部模式常规和非常规扫描次数、高曝光剂量扫描对家兔急性脾组织病理变化的影响。方法将46只大白兔随机分成3组：（1）高曝光剂量CT扫描组36只。采用约为常规剂量2倍的腹部CT扫描模式,对大白兔进行全身扫描,再将其分两大亚组,每组18只。①腹部模式一次性扫描组（一次性扫描组）：CT扫描层厚为2.5mm分别连续扫描3、6、9、12、15和18次,48h后剖杀;②腹部模式重复扫描组（重复扫描组）：CT扫描层厚以5mm分别连续扫描2、4、6、8、10和12次,24h后重复上述扫描,24h后剖杀。（2）常规CT扫描组：5只,采用常规次数和曝光剂量对大白兔进行全身扫描,48h后剖杀。（3）健康对照组：5只。所有实验动物取脾组织作病理分析。结果光镜病理结果：①一次性扫描组：连续扫描6次时出现红髓髓窦略扩张、淤血;连续9-18次扫描后,脾脏出现红髓髓窦扩张、淤血,可见网状组织细胞增生和吞噬含铁血黄素。②重复扫描组：共8次扫描时出现红髓髓窦轻度扩张、淤血,散在中性粒细胞浸润;16-24次扫描后,脾脏出现红髓髓窦扩张、淤血,散在中性粒细胞浸润,间或有组织细胞增生。结论常规脾脏CT扫描是非常安全的;在非常规扫描次数和高曝光剂量下,CT辐射可能会引起家兔急性脾组织的异常病理变化。

The preliminary pathological study of high_dose CT radiation damage on rabbit spleen

Objective To investigate acute CT radiation damage on rabbit spleen after the whole_body CT scans or high_dose abdominal CT scan model.Methods The 46 New Zealand white rabbits were randomly assigned into 3 groups.High_dose groups including single CT scanning group(group 1) and repeated CT scanning group(group 2) with high_dose abdominal CT scan models 18 rabbits each.The other two groups were routine_dose CT scanning group and control group 5 rabbits each.Both group 1 and 2 were divided into subsection 1_6,2_24 times of continuous or discontinuous CT scans with 240 mAs. 140 kVp were performed on each rabbit.The rabbit spleens were collected at 48 h or 24 h after CT scanning and the pathological examination were performed.Results (1) Ligh microscope showed as follows:1 group 1:slight splenic damage occurred at 6 times of continuous CT scanning.After 6_18 times of continuous CT scanning,the spleen was slightly swelling at first,followed by hydropic or fat degeneration,constriction or emphraxis.And the hyperplasia of mesh histiocyte and the blood containing Fe was observed.2 group 2:slight splenicdamage occurred at 8 times of CT scanning.After 8_24 times of CT scanning,spleen showed slight or mild swelling at first,followed by moderate or diffuse swelling,hydropic degeneration,and dispersed karyopyknosis of splenic cell near central vein.(2) The splenic tissues of routine_dose CT scanning group were normal with immunohistochemistry assay.Conclusions Routine_dose CT scanning is very safe to rabbit spleen,but high_dose CT scanning with non_routine scan times may cause acute pathological splenic damage.