INFLUENCE OF TUMOR DEPTH, BLOOD ABSORPTION AND AUTOFLUORESCENCE ON MEASUREMENTS OF EXOGENOUS FLUOROPHORES IN TISSUE

We investigated the influence of tumour depth and differences in blood concentration and autofluorescence between tumour and normal tissue o n the fluorescence of a tumour-localising agent. Carotenoporphyrin, CP (Me)(3), mas injected into rats and nude mice with intradermal tumours . On the tumours an incision was made, uncovering 2 mm(2) of the tumou r, and fluorescence measurements, including excitation-emission maps a nd fluorescence ratios, were made on skin. covered and uncovered tumou r, The measured fluorescence ratio in the uncovered tumour showed a th ree- to tenfold increase compared to the covered tumour, We used a one -dimensional layered tissue model to analyse the data, In conclusion, even with a high tumour-selectivity deeper lying tumours cannot always be detected, particularly if the tumour has a high blood concentratio n or low autofluorescence intensity.