Laser-induced autofluorescence measurements on brain tissues.
It was demonstrated that comparison of the autofluorescence spectra induced with laser radiation in ultraviolet and visible allows the identification of brain tumor tissues and normal tissues as well as the difference between them. The measurements were performed on homogenates to ensure an optimal reproducibility of the results. We conclude that the autofluorescence spectra of the tumor samples are close to those measured for normal tissues, but there are differences between them that allow distinguishing the tumor from the normal tissue. One difference is that for each pair of tumor/normal tissue samples, the peak autofluorescence for the normal tissue is shifted with respect to that for the tumor-typically between 10 and 20 nm; overall autofluorescence intensity is also different for the components of the same pair, the difference being in the range 15%-30%. A parameter that can also be used is the variation of the ratio of some fluorescence intensity peaks between normal and tumor tissue samples. Measurements of this parameter yielded variations ranging between 10% and 40%. Another conclusion of the study is that in vitro experiments show that it is mandatory to use pairs of samples (normal/tumor tissue) taken from the same patient. The results show that, after further experimental in vitro tests, the method may be adapted to real-time intraoperative conditions by measuring the autofluorescence of the tumor and of the adjacent normal tissue.
Pascu
Alexandru
A
Department of Laser, National Institute for Laser, Plasma and Radiation Physics, Str. Atomistilor nr. 409, Magurele, Bucharest, Romania.
Romanitan
Mihaela Oana
MO
Delgado
Josè-Maria
JM
Danaila
Leon
L
Pascu
Mihail-Lucian
ML
D000596:Amino Acids / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D001254:Astrocytoma / Q000175:diagnosis / Q000503:physiopathology; D001921:Brain / Q000473:pathology* / Q000503:physiopathology / Q000528:radiation effects; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology; D003952:Diagnostic Imaging / Q000379:methods; D005453:Fluorescence; D005456:Fluorescent Dyes; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007834:Lasers; D009448:Neurochemistry / Q000379:methods; D010775:Photic Stimulation / Q000379:methods*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
D000596:Amino Acids; D005456:Fluorescent Dyes