Abstract

We assessed the ability of laser induced autofluorescence after excitation with ultraviolet laser light at 308 nm (AF308) to distinguish neoplastic urothelial bladder lesions from normal or nonspecific inflammatory mucosa.

In this project 43 patients with bladder tumors were investigated. Guided through the 5-ALA induced Fluorescence Endoscopy (AFE) the autofluorescence of the red fluorescing areas and the inconspicuous, adjacent normal mucous membrane were measured spectroscopically. The fluorescence excitation was carried out with a XeC1 - Excimerlaser operating at 308 nm. For the evaluation of the spectra we calculated the intensity-ratios between 335 nm to 370 nm (R1) and 335 nm to 430 nm (R2) and correlated them with the histological findings of the biopsies taken.

We analyzed 114 biopsies, which showed that the intensity ratios for normal mucosa, inflammatory mucosa, edema and scars are a factor of two to seven higher than CIS and tumorous tissue. For a intensity - ratio of 1.75 for R1 and 6.5 for R2 as a threshold value between malignant and benign tissue, 20 tumors were detected as right positive and one visible TCC was false negative. For these threshold values the sensitivity was 95% for AF 308 and 91% for AFE. Comparing the specificity we ended up with 61% for AFE and 81% for AF 308. By combining the two methods we calculated a sensitivity of 91% and a specificity of 86%.

The combination of a sensitive imaging technique like AFE and a more specific fluorescence probe technique with 308nm excitation could reduce the amount of biopsies taken and result in an improved specificity.

© 2000 Optical Society of America