ABSTRACT
Objective To investigate acute CT radiation injury on rabbit liver after the whole body CT scans with high-dose abdominal CT scan model.Methods The forty-six New Zealand white rabbits were randomly assigned into 3 groups.High-dose CT scanning groups included one-off CT scanning group(group 1)and repeated CT scanning group (group 2)with high-dose abdominal CT scan modes,and 18 rabbits in each group.The other two groups were routine-dose CT scanning group(n=5)and control group(n=5).Rats in both group 1 and 2 were divided into 6 subgroups(n= 3).Four to twenty-four times of continuous or discontinuous CT scans with 240 mAs and 140 Kv were performed on every rabbit.The liver samples of every animal were eoUected at 48 h or 24 h after CT scans and pathological examination and immunohistochemistry assay of Cpp32 and Bax expression were performed.Results(1)Light microscope showed①in group 1,slight hepatic injury occurred at 6 times of continuous CT scanning;after 6～18 times of continuous CT scanning,hepatocytes were slight swelling at first,followed by hydropic or fatty degeneration,constriction or emphraxis of hepatic sinuses,puncture necrosis of hepatocytes,and local hepatic hemorrhage;②in group 2:slight hepatic injury occurred at 8 times of CT scanning,and after 8～24 times of CT scanning,hepatocytes were slight or mild swelling at first,followed by moderate or diffuse swelling,hydropic degeneration,and dispersed karyopyknosis of hepatocytes near central vein.(2)Immunohistochemistry assay showed:①in group 1,positive expressions of the apoptosis-inducing protein Bax and Cpp32 were observed in part of liver samples,the expressions of Bax and Cpp32 were correlated with CT radiation dose;②in group 2,positive expressions of the apoptosis-inducing protein Bax and Cpp32 were found in every subgroup,but the expression was not correlated with CT scan times.(3)The hepatic tissues of routine-dose CT scanning group were normal under the light microscope and immunohistochemistry assay.Conclusion Routine-dose CT scanning on liver is very safe,but high-dose CT scanning with non-routine scan times may cause acute pathological hepatic injury and hepatocyte apoptosis.