H&E stain and CLI of a 21-day post-injection fibrosarcoma tumor. (a) H&E stained histology sample showing the tumor with necrotic core and large blood vessel. (b) H&E stained histology sample showing a magnified section of a large subcutaneous blood vessel. (c) H&E stained histology sample showing a magnified section of the necrotic core. The accumulation of red blood cells within the necrotic core is indicated by the thin arrows, while the white spaces showing the location of cell necrosis are indicated by the thick arrows. (d) CLI of the mouse from where the H&E stain was taken as indicated by the yellow line with the tumor outlined in red. The necrotic core and the large blood vessel entering the tumor are clearly seen with 21% and 12% reduction in radiance, respectively.