PROCEEDINGS ARTICLE | June 18, 1993
Proc. SPIE. 1881, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy II
KEYWORDS: Tumors, Tissues, Spectroscopy, Skin, Luminescence, Fluorescence spectroscopy, Laser induced fluorescence, Laser spectroscopy, Lymphatic system, Animal model studies
The goal of this study was to detect the presence of benzoporphyrin derivative-monoacid (BPD-MA) in tissues of a tumor bearing animal model. Eighty one Lobund-Wistar rats, inoculated with Pollard rat adenocarcinoma cells, were used. This animal model exhibits unique predictable, unilateral, metastatic spread. The animals were injected intravenously with 0.75 mg/kg of BPD-MA. A Helium-Cadmium (He-Cd) laser (442 nm, 17 mW) was used as an excitation source and coupled to a 400 micrometers core diameter fiber. Following laparotomy, exploration of the abdominal and inguinal area was performed with laser induced fluorescence. Fluorescence spectra of the primary tumor, bilateral lymph nodes, and various organs were recorded. Fluorescence measurements were conducted four hours post injection. The spectra obtained were characterized by a broadband autofluorescence (approximately 540 nm) and a characteristic peak of BPD-MA (approximately 690 nm). Overall, the BPD-MA concentration was higher in lymph nodes than in the skin, kidney, large bowel, muscle or spleen. Skin exhibited the lowest fluorescence intensity ratio, indicative of a lower drug concentration in this tissue. In summary, our results suggest that laser induced fluorescence spectroscopy may provide an alternative way of assessing the biodistribution of BPD-MA or other photosensitizers.
