CELL THICKNESS MEASUREMENTS BY CONFOCAL FLUORESCENCE MICROSCOPY ON C3H10T1 2 AND V79 CELLS/

Measurements of C3H10T1/2 and V79 cell thickness were performed on liv ing cells by confocal laser fluorescence microscopy. Thickness distrib utions are reported for cells growing as a monolayer (on mylar and gla ss) and suspended in their medium. Mean values for cells grown on myla r (corrected for refractive index effects) are 2.9+/-0.6 and 6.1+/-1.0 mu m for C3H10T1/2 and V79 cells respectively. Mean values of the dia meters of cells suspended in their medium are 13.0+/-1.6 and 9.3+/-1.4 mu m for C3H10T1/2 and V79 respectively. Knowledge of cell thickness, as irradiated, is of central relevance for studying the relative biol ogical effectiveness of low energy, poorly penetrating radiations. It can be concluded, from the measured cell thickness distributions, that with C3H10T1/2 cells grown on mylar, the LET variation through the wh ole cell is within 20% for protons and alpha-particles with energies d own to 0.6 and 2.5 MeV respectively. From a comparison with thickness values reported in the literature for living or fixed embedded cells g rowing on plastic substrate, mean values between 2.4 and 3.4 mu m and between 6 and 7.5 mu m could be assumed for C3H10T1/2 cells and for th e most widely used V79 cell lines respectively.