Evaluation of the microangioarchitecture of tumors by use of monochromatic x-rays.

Abstract

The purpose was to compare differences in the depiction of small vessels in tumors seen on microangiograms from a conventional soft x-ray system with those from a synchrotron radiation system and to evaluate the microangioarchitecture of these tumors and the growth of neovascularization. VX2 carcinomas transplanted to the auricles of 15 rabbits randomized into three groups were investigated after 1, 3, and 7 days. Five normal rabbits were the controls. Barium sulfate, to which sufficient gelatin had been added, was injected into the auricular artery. Microangiograms of auricle specimens were obtained with both a conventional soft x-ray system and a synchrotron radiation system. The conventional x-ray system could detect vessels with diameters of approximately 100 microm, whereas the monochromatic synchrotron radiation system could detect small vessels with diameters of less than 25 microm. On day 1, there was moderate vascularization and flexure vessels were present in the transplantation area. On day 3, dilated vessels were present in the peripheral areas of the tumors and tortuous vessels in the central areas. On day 7, hypovascular areas had increased in the central area. The synchrotron radiation system confirmed the growth of neovascularization in the tumors. This system should provide a useful tool for evaluating the microangioarchitecture of tumors.