Photodynamic therapy using hematoporphyrin derivative and He-Ne laser irradiation in Erlich tumor: an experimental study on mice

In vitro (absorption spectroscopy) and in vivo (fluorescence microscopy) studies before and after the uptake of intraperitoneal injected Hematoporphyrin Derivative (HpD) were made in mice. The absorption spectrum of HpD is characterized by four bands in the visible region with decreasing absorption towards longer wavelengths (510 nm, 540 nm, 568 nm and 621 nm). These spectra were obtained only at low concentration (10-5 M). After (15 - 30) minutes postirradiation (He-Ne laser, 1 mW) the features of curves were the same with those of nonirradiated samples but with a deplacement of wavelengths. The presence of laser emitting products was pointed out by fluorescence microscopy (cryostat section in fluorescence microscopy).