Light attenuation of human liver and hepatic tumors after surgical resection

The attenuation of light in the human liver and hepatic tumors was measured in the 410-, 630-, and 670-nm wavelengths. Optical fibers coupled to a photon-counting system were positioned within the tissues to determine the light flux and were attached to a caliper gauge to measure the fiber separation distance. Five resected specimens each of metastatic carcinoma from the colon with normal liver and hepatocellular carcinoma with cirrhosis of the liver were used immediately after surgical resection. Metastatic tumors showed the deepest penetration at all wavelengths. A significant difference appeared between the cancerous and noncancerous tissues (P less than .01). Additionally, the cirrhotic liver tissues showed significant deep penetration by all wavelengths examined in comparison with normal liver tissues (P less than .01). The implications of light dosimetry for clinical application from the results of our study are discussed.