The metabolism of ~(32)P-CP-PLLA seed implanted in the liver and its damage to the normal liver tissue: a study in the experimental dogs / 介入放射学杂志

ABSTRACT

Objective To investigate the effects of intratumoral implantation of ~(32)P-CP-PLLA seeds on the normal canine liver tissue and to exolore the metabolism of ~(32)P-CP-PLLA seeds implanted in the liver of experimental dogs.Methods Twelve beagles were enrolled in this study.The dogs were randomly and equally divided into four groups:group A(185 MBq),group B(370 MBq),group C(740 MBq)and group D(0 MBq).By using laparotomy procedure ~(32)P-CP-PLLA seeds were implanted into dog's liver.CT scan was performed before operation as well as before the dog was sacrificed.All dogs were sacrificed three months after the implantation.Before the procedure and 1,2,4,8 and 12 weeks after the procedure the blood tests and serum biochemical tests were conducted.One dog from group B and group C was selected respectively and was fed in a metabolic cage.Within one month after the procedure the cpm in feces and in urine was determined every 24 hours.One dog was picked out from each of the three groups and was punctured to get its liver tissue for pathologic exam each time at 1,2,4,8 and 12 weeks after the implantation,and SPECT imaging was also performed at the same time.Pathologic study,both macroscopic and microscopic(including optical and electronic microscopy)was made to observe the liver damage after the dog was sacrificed.The statistical analysis was processed by using SPSS 13.0 software and the measuring data were expressed with mean±standard deviation((x)±s).Results Two months after the procedure,serological examination found that the serum alkaline phosphatase(BKP)in both group Band group C was significantly higher than that in other groups,the difference was statistically significant (P ＜0.05),and the BKP levels returned to normal in three months.The postoperative 30-day inspection of the urine showed that the radioactive particles slowly released into the body and eliminated from the body with the urine and feces,mainly through the renal excretion.The 30-day cumulative percentage of eliminated radioactive dose in the urine and in the feces was 6.34% and 11.64% respectively.No sign of particle displacement was found on SPECT imaging.On autopsy three months after the implantation,the size of the radioactive seeds became smaller and fragile.With the radioactive dose used increasing,the area of liver damage at the site of seed implantation became bigger,which was demonstrated on CT scan,macroscopic exam and pathologic study.The local damaged focus of the liver caused by ~(32)P-CP-PLLA seeds was manifested as a spherical lesion which was encysted by a layer of fibrous tissue with an edematous zone peripherally.Conclusion The implantation of ~(32)P-CP-PLLA seeds in dog's liver causes only localized hepatic damage with no general adverse effects.The implanted seeds can slowly release the radioactive dose and will not immigrate to other organs in the body.Besides,the seeds possess excellent stability,targeted orientation and safety.