Artikel
Laserspectroscopy in 5-ALA treated gliomas: spectroscopical evaluation of 5-ALA fluorescence uptake and kinetics in human glioma cells
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: 5-aminolaevulinic acid (5-ALA) has improved surgical therapy of malignant gliomas. However, there is a lack of knowledge concerning 5-ALA uptake and fluorescence kinetic in different histologies. Aim of this study was to detect differences in malignant gliomas concerning uptake kinetic and fluorescence of 5-ALA loaded glioma cells by spectroscopy.
Methods: Sample examination took place 4 hours after 5-ALA application. Before surgery, 20 mg /Kg bodyweight 5-ALA was given. Tumor slices which showed a maximum of fluorescence using the surgical microscope at the beginning and during resection, were cut into 1 cm3 blocks, incubated in 5% glucose solution and used for spectroscopical evaluation by an un-pulsed diode laser with a wavelength of 405 nm and with an energy of 30 mW combined with a spectroscope. The distance between laser and example was 1 mm. Measurements were performed every hour for 1 second in order to reduce a photo bleaching effect starting at baseline 4 hours after 5-ALA application and ending 14 hours after 5-ALA application.
Results: The tumors of 8 patients were evaluated of which 5 were glioblastomas (GBM) and 3 anaplastic astrocytomas (AA). We observed a reduction in fluorescence accumulation in the cells in a negative exponential way. A photo bleaching effect was detected in slices, analyzed for more than 1 second. AA showed significantly lower 5-ALA-uptake as well as a significantly lower curve in total fluorescence compared to GBM.
Conclusions: In gliomas, 5-ALA fluorescence decreases in a negative exponential curve helping to interpret the kinetics and intraoperative findings. This observation may be useful for intraoperative predictions of histology.