In tumor localization based on the tumor-seeking properties of hematoporphyrin derivative (HpD),1 induced red fluorescence at wavelengths λ > 600 nm is normally observed. However, there is frequently a background red fluorescence even in the absence of HpD injection. A much improved contrast between tumor tissue and normal tissue can be achieved if simple functions of fluorescence intensities of different wavelengths are monitored.2 We have performed a model experiment on rats with induced leg tumors employing N2 laser excitation and optical multichannel detection. Tissue from 15 different organs were investigated for rats that had received a 5-mg/kg body weight injection 1–4 days prior to the measurements. In Fig. 1 spectra of tumor tissue from HpD-injected and control rats are shown as well as a spectrum for muscle at the tumor position but on the unaffected leg.
© 1984 Optical Society of AmericaPDF Article