论文部分内容阅读
目的探讨腹部模式常规和非常规扫描次数。高曝光剂量的CT扫描对家兔肝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：分两大亚组,每组18只,进一步分6个小组,每小组3只。采用高曝光剂量(约为常规2倍曝光剂量)的腹部CT扫描模式．对大白兔进行全身扫描。①腹部模式一次性扫描组(以下简称一次性扫描组)：CT以2．5mm层厚分别连续扫描3、6、9、12、15、18次,48h后剖杀；②腹部模式重复扫描组(以下简称重复扫描组)：CT以5mm层厚分别连续扫描2、4、6、8、10、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)正常对照组：5只。所有实验动物取肝组织作病理检查和凋亡相关基因Cpp32、Bax蛋白的免疫组化分析。结果(1)高曝光剂量CT扫描组光镜病理结果：①一次性扫描组连续扫描6次时出现轻微肝损伤；连续6～18次扫描后,肝细胞逐渐由轻微或局限性浊肿变为弥漫性浊肿、水样变性或脂肪变性、肝窦狭窄或闭塞、点状肝细胞坏死和局部肝出血。②重复扫描组共8次扫描时出现轻微肝损伤；8～24次扫描后,肝细胞逐渐由轻微到弥漫性浊肿、水样变性,近中央静脉周围肝细胞散在性核固缩改变。免疫组化结果：①一次性扫描组部分肝组织对Bax、Cpp32呈阳性表达,而且随着扫描次数的增加,其阳性表达也多更高,肝细胞的凋亡程度也随之加重。②重复扫描组各小组扫描肝组织Bax和cpp32均出现阳性表达,其阳性表达程度与扫描次数无明显相关性。(2)常规CT扫描组：实验肝组织光镜下无发生明显的病理变化。Bax、Cpp32呈阴性表达。结论常规肝脏CT扫描是非常安全的：但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肝组织的异常病理变化。
Objective To explore the abdomen patterns of conventional and unconventional scanning times. Effect of High Exposure Dose CT Scanning on Pathological Changes of Liver in Rabbits. Methods 46 rabbits were randomly divided into three groups: (1) high exposure dose CT scan group 36: divided into two subgroups, each group of 18, further divided into 6 groups, each group of 3. Abdominal CT scan mode with a high exposure dose, which is about twice the exposure dose. Whole body white rabbits were scanned. ① abdomen pattern of one-time scanning group (hereinafter referred to as the one-time scanning group): CT 2.5mm layer thickness were continuously scanned 3,6,9,12,15,18 times, 48h after the cut; abdomen pattern repeat scan group (Hereinafter referred to as the repeat scan group): CT scan 5mm, 6th, 8th, 10th, 12th scan continuously, respectively. (2) The conventional CT scanning group: 5, using the conventional number and exposure dose of whole body white rabbits were scanned, 48h after the cut. (3) normal control group: 5. All the experimental animals were taken liver biopsy and immunohistochemical analysis of Cpp32, Bax protein. Results (1) Pathological results of high-dose CT scanning light microscopy: (1) slight liver injury occurred in 6 consecutive scannings in one-time scanning group; and after 6 to 18 consecutive scannings, hepatocytes gradually changed from slight or localized swelling to Diffuse turbidity, watery degeneration or steatosis, sinusoidal stenosis or occlusion, punctate hepatocyte necrosis and local liver hemorrhage. ② repeated scan group a total of 8 scans showed slight liver injury; 8 to 24 scans, the liver cells gradually from mild to diffuse turbidity, watery degeneration, near the central venous scattered hepatosplenomegaly change. Results of immunohistochemistry: ①The positive expression of Bax and Cpp32 in some liver tissues of one-time scanning group was higher than that of normal group, and the positive expression of Bax and Cpp32 was also higher with the increase of scanning times, and the degree of hepatocyte apoptosis was also increased. (2) The positive expression of Bax and cpp32 in the liver tissue of each group in the repeat scanning group showed no significant correlation with the number of scanning. (2) Conventional CT scan group: no significant pathological changes occurred in the experimental liver tissue under light microscope. Bax, Cpp32 negative expression. Conclusions Conventional hepatic CT scan is very safe: CT radiation may cause abnormal pathological changes in acute liver tissue in rabbits under the irregular scanning frequency and exposure dose.