Interaction of 144Ce and partial hepatectomy in the production of liver neoplasms in the Chinese hamster

Chinese hamsters (LF random bred) were injected intraperitoneally with a range of levels of 144Ce-144Pr citrate. After the injection they either had no further treatment or were partially hepatectomized at either 20 days before injection or 20 or 200 days after injection. Control hamsters were subjected to a similar surgical schedule. The average radiation dose of the liver at sacrifice ranged from 15 to 110 Gy and produced from 0.44 to 3.40 metaphase chromosomal aberrations per liver cell. Thus aberration frequency was very high when live tumors were observed. Of the 330 animals injected with 144Ce, 108 developed primary neoplasms in the liver while no liver tumors were observed in 97 control animals. When animals with similar survival and total lifetime dose to the liver were compared, partial hepatectomy performed 20 or 200 days after 144Ce injection significantly increased liver tumor incidence. Partial hepatectomy before 144Ce injection had no effect. Enhanced cell division from partial hepatectomy plays a role in the induction of live neoplasms following low-dose-rate β-γ exposure from the radioisotope 144Ce