Microautoradiography of an F9 teratocarcinoma dissected from a nude mouse, after injection of radiolabeled L19. Two different magnifications of a microautoradiography of a F9 mouse teratocarcinoma. The radiolabeled L19 accumulates around vascular structures within the F9 mouse tumor but not in the surrounding normal mouse tissue (A). At higher magnification (B) within the lumens of some vessels, the red blood cells are visible (arrow). The bar corresponds to 10 μm.