Laser Spectroscopy For The Study Of The Liver Disease Diagnosis

Laser-induced auto-fluorescence spectra of serum of hepatocirrhosis patients and liver fibrosis rats are investigated in this paper. The purpose is to find difference between serum of healthy human and liver diseases patients in fluorescence spectra and to study whether the laser-induced auto-fluorescence spectra may diagnose liver diseases.Fluorescence spectra of serum were collected at the excitation of Ar-ion laser (514.5nm, 488.0nm and 476.5 nm). The spectra were analyzed to calculate relative intensity ratio, bandwidth, as well as the second derivative spectra and Multi-peak Gauss fit of fluorescence spectrum.The results of the second derivative spectra analysis indicate that there are three minimum values near 528nm (515nm/human), 553nm and 587nm from 490nm to 600nm. The ratio of the first and second minimum values of health is smaller than that of disease. Multi-peak Gauss fit of fluorescence spectrum may obtain similar reslut.Besides analyzing the second derivative spectra, the relative intensity ratio and bandwidth of fluorescence spectra of serum of hepaocirrhosis patients were calculated. The results indcate that the relative intensity ratio(I500/I600) of healthy serum is smaller than that of disease at 488.0nm excitation, whereas the ratio(I490/I600) is larger at 476.5nm excitation. At the same time, the bandwidth of health is larger than that of disease at 488.0nm and 476.5nm excitation.The paper has analyzed the main fluorescent materials from 490nm to 640nm, and considers that difference of spectra between health and disease is due to difference of the concentration of bilirubin (fluorescent peak lie near 515nm) and porphyrin derivative (fluorescent peak lie 590-630nm), and the difference is characteristic change of fluorescence spectrum of liver disease serum. At the same time, the result indicates when intensity change of fluorescence of porphyrin derivative is analyzed, 476.5nm excitation should be used, whereas intensity change of fluorescence of brilrubin is analyzed, 488.0nm excitaion should be used, and the derivative spectra of serum is an effective method to analyse liver disease.