Spectral analysis of lung cancer serum using fluorescence and Raman spectroscopy

Spectral changes of lung cancer serum in the process of tumor evolution was investigated in this study. We kept close watch on the tumor progression of a group of patients, and measured their serum spectra using 488.0nm and 514.5nm excitation of an Ar-ion laser once a week. There was no apparent change observed in fluorescence spectrum in different period. However, the relative intensity of three Raman peaks (mode A, B and C) decreased every week later. For quantitative analysis of such changes, a parameter Ir (relative intensity of C Raman peak) was introduced and Ir-value was calculated. Calculation showed that Ir-value was degressive with tumor evolution, but β (Ir5145 /Ir4880) varied irregularly. To the end, no Raman peak was observed. We assumed that three Raman peaks were derived from beta carotene. It indicated that the content of beta carotene decreased with the aggravation of lung cancer.