Clinical recording of laser-induced fluorescence spectra for evaluation of tumour demarcation feasibility in selected clinical specialities

Compact fiber-optic fluorosensor using a continuous-wave violet diode laser and an integrated spectrometer

“…All spectra presented in the present paper were treated in this way and further handled with Microsoft Excel software. Since the laser source is not pulsed and the detection is not gated in contrast to more complex systems, 15,16 there is a risk that ambient light may add an undesired background. However, since the fiber is put in contact with the specimen under study, the ambient light is effectively blocked from entering the fiber in most cases.…”

“…Sensitizers, including porphyrins, phtalocyanines and chlorines, exhibit characteristic fluorescence signatures in the near infrared spectrum that can serve for clinical tumor diagnostics. 8,15 By irradiation of red light the same compounds can also mediate tumor cell necrosis through selective singlet oxygen release ͑photodynamic therapy 19 ͒. A particularly interesting sensitizer is protoporphyrin IX, which is synthesized at a higher rate in malignant tumors after administration of ␦-amino levulinic acid.…”

“…Our group has developed several systems of this kind, which have been employed in medical and environmental monitoring. Original systems 15 were quite bulky, whereas later developments resulted in more portable equipment. 16 In the present paper we report on the construction and utilization of a highly compact fiberoptic fluorosensor of the size 22ϫ13ϫ8 cm 3 .…”

Laser-induced fluorescence in malignant and normal tissue in mice injected with two different carotenoporphyrins

“…The optical set-up used for the recordings of laser-induced fluorescence is similar to one previously described (Andersson-Engels et al, 1989a, 1991a and will only be briefly described here. The excitation source was a nitrogen laser (Laser Science VSL-337ND) used alone or as pump source for a compact dye laser (Laser Science DLM220).…”

“…Similar studies have been carried out previously using other substances such as HpD (Svanberg et al, 1986) In addition to simply using the substance-related fluorescence, the endogenous fluorescence emanating from natural fluorophores in the tissue may also be included in order to enhance the tumour demarcation towards healthy peritumoral tissue. It has been shown that the autofluorescence, with its intensity maximum at about 500 nm when excited in the near-UV region, shows a lower intensity in tumour than in normal tissue (Ankerst et al, 1984;Profio & Sarnaik, 1984;Andersson-Engels et al, 1989b, 1991aCothren et al, 1990;Hung et al, 1991;Baert et al, 1992). To some extent, the reason for the decreased autofluorescence seems to be a decrease in the amount of oxidised forms of flavins in malignant tissue (Hung et al, 1991).…”