Fig. 6.

Clonogenic survival data for RIF cells incubated with Photofrin or G2 during 18 h and irradiated with 630 nm light. Hollow symbols – photosensitizer is absent from the medium during irradiation. Filled symbols – photosensitizer is left in the medium during irradiation. Surviving fractions are calculated as fractions of the colony-forming cells in the treated samples compared to controls that received neither photosensitizer nor light. The data are shown as average ± SE from 3 independent studies. * No surviving cells were found for this condition – the point indicates the lower limit of the assay sensitivity.