Evaluation of radiation damage of transcatheter hepatic arterial embolization using phosphorus-32 microspheres in a swine model

Objective: To evaluate the acute and sub-acute toxic response to transcatheter hepatic arterial embolization of Phosphorus-32 glass microspheres (32P-GMS) in pigs. Methods: Selective transcatheter hepatic arterial embolization was performed in 10 healthy domestic pigs using 46-76 μm 32P-GMS (5 pigs, 48-190 Gy) and nonradioactive glass microspheres (5 pigs) as control group. Blood tests including complete blood count, liver and kidney function tests were measured. The distribution of 32P was monitored. The pigs were sacrificed at 1,2,4,8 and 16 weeks, respectively. Microscopic and ultrastructural histopathology of the liver and kidney was evaluated. Results: 32P-GMS was distributed evenly over the liver perfused. The GMS were located in the hepatic micro-arteries and few collateral feeding arteries were formed. Transient elevation of transaminases was observed in all pigs following 32P-GMS administration. No evidence of myelosuppression was found. Swelling and vacuolar degeneration of hepatocytes and lymphocyte infiltration in the liver were demonstrated in the pigs injected with 32P-GMS. However, no hepatic parenchymal necrosis occurred. Conclusions: This study suggests that intraarterial hepatic administration of 32P-GMS with dose less than 190 Gy is well tolerated