Tumor imaging with x-rays using macrophage uptake of radiopaque fluorocarbon emulsions

Radiopaque fluorocarbon (RFC) emulsions were prepared with small particle size and high concentration of the fluorocarbon. When RFC emulsions were injected intravenously in hamsters, rats, and mice with eight types of malignant tumors, the tumors became radiopaque, except in the mice with spontaneous teratoma of the ovaries. Tumors as small as 3 to 4 mm could be defined radiographically using routine x-ray techniques. The tumors remained radiopaque for days to weeks after injection. Light and electron microscopy revealed characteristic fluorocarbon vacuoles primarily in the tumor macrophages. Thus RFC emulsions may be useful in detection of malignant tumors.