Abstract
We have been developing a photodynamic cancer diagnosis and treatment system.This system consists of an excimer laser pumped dye laser which emits beams on wavelengths of 405 and 630 nm, and an image and spectroscopic analyzer of the endoscopic findings. In diagnosis, the 405 nm laser beam is applied to the tissue to detect the fluorescence of HpD. At the same time, the light of an Xe lamp is also applied to enable observation. When light intensities of the laser and the Xe lamp are strong, HpD deteriorates rapidly. The HpD fluorescence becomes weak and changes its spectral shape. In this case the analysis does not lead to a conclusive diagnosis. We investigated this phenomenon using two kinds of samples: HpD absorbed filter papers and tissues from an experimental cancer mouse which was injected with HpD beforehand. For the cancer tissue, the intensity of the fluorescence after 14 minutes became 1/4 of the initial value at 60,000 lux Xe light illumination.
