Tolerance of canine portal vein anastomosis to intraoperative x-irradiation.

Tolerance of surgical portal vein anastomosis to intraoperative radiation therapy (IORT) was studied in dogs after single doses of zero, 10, 20 and 40 Gy (290 kVp x-rays). Portal venography was performed prior to IORT and before sacrificing. The dogs were sacrificed 3 and 12 months respectively after irradiation. Portal venography revealed no radiation induced anastomotic stenosis. Autopsy disclosed macroscopic periportal fibrosis in all dogs, independent of radiation dose and observation periods. Microscopically, the three tunicas of the vein did not show any pathological changes after any dose level.