[Superficial bladder cancer detection using diffuse reflectance spectral ratio R540/R575 of oxygenated hemoglobin...

A low-cost, fast, and noninvasive method for early diagnosis of malignant lesions of mucosa tissue based on diffuse reflectance spectra was applied in the study of the optical biopsy of superficial human bladder cancer. In the present paper, differential diagnosis of superficial human bladder cancer was studied using the diffuse reflectance spectral ratio (R540/R575) of the oxygenated hemoglobin absorption bands at 540 and 575 nm in vitro. Diffuse reflectance spectra for mucosa/submucosa tissues of normal bladder and superficial bladder cancer were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that there were three the diffuse reflectance spectral dips at 415, 542 and 577 nm respectively for mucosa/submucosa tissues of normal bladder and superficial bladder cancer in the spectral range from 400 to 600 nm. The mean diffuse reflectance spectral ratio (R540/R575) of normal bladder mucosa/submucosa tissue decreased slowly with time increase after surgical excision, and the mean diffuse reflectance spectral ratio (R540/R575) of superficial bladder cancer mucosa/ submucosa tissue also decreased slowly with time increasing after surgical excision. The mean diffuse reflectance spectral ratios (R540/R575) of normal bladder mucosa/submucosa tissue were 111%, 107%, 104% and 102% after 2, 3, 4 and 5 h after surgical excision respectively, and those of superficial bladder cancer mucosa/submucosa tissue were 98.4%, 95.5%, 93.1% and 91.6% after 2, 3, 4 and 5 h after surgical excision respectively. There were significant differences in mean diffuse reflectance spectral ratio (R540/R575) for mucosa/submucosa tissues between normal bladder and superficial bladder cancer after 2, 3, 4 and 5 h after surgical excision respectively (p < 0.05). Differences in mean diffuse reflectance spectral ratio (R540/R575) for mucosa/ submucosa tissues between normal bladder and superficial bladder cancer were 12.6%, 11.5%, 10.9% and 10.4% after 2, 3, 4 and 5 h after surgical excision respectively. It is obvious that pathological changes in bladder mucosa/submucosa tissues induced changes in the component and structure of the tissues, and especially quantitative changes in oxyhemoglobin and de-oxyhemoglobin of tissues obviously. Conclusion of the study provides a new method that can be applied to rapid, low-cost and noninvasive optical biopsy of superficial bladder cancer.