Light and laser induced fluorescence spectroscopy (LIFS) and their biomedical applications

The signals produced by laser and light induced emission spectroscopy can be used to characterize different components of tissue. This method enables us to identify proteins and different metabolic mediators. Using extensive emission light at a certain wavelength and analyzing it with mathematical algorithms, we can characterize individual anatomical structures in the tooth, tissue alkalinity or acidity, blood perfusion or presence of neoplasm in any tissue. To enhance the sensitivity of our detection method we can use different fluorescence drugs. These drugs can be used to tag malignancy (neoplasm), making this method one of the most rapidly developing area in the diagnosis of cancers. A XeCl (308 nm, nanosecond pulsed) or He-Cd (442 nm, CW) laser output was reflected at a right angle by a dichroic mirror. It was focused at the input of a 400 μm core diameter fiber optic probe, The output of the lasers at the distal end of the fiber was 5 mJ/pulse or 17 mW. Fluorescence was collected using the same fiber and transmitted through the dichroic beamsplitter and guided via a fiber bundle to a 0.5 spectrograph. The light was then imaged at the modified output port. A 1024 element linear diode array detector (EG&G 1422G) was attached to the exit port. Final data was displayed on the screen of the optical multichannel analyzer (OMA III, EG&G). We recorded background spectra before excitation. This was subtracted from the resulting data. Calibration was not required because intensity ratios were used instead of absolute intensities. The mean and standard deviation of the designated curve segment was then computed