Scintillation fluid shortens exposure times in autoradiography

Premixed, commercially available scintillation fluids were used to reduce exposure time of tritium (3H) and iodine-125 (125I)-labeled whole cells, and of 3H-labeled Giemsa-banded chromosome preparations. Emulsion-coated slides were dipped into scintillator for no longer than 2 min and exposed in the dark at 4 degrees C. Maximal values for percentage of human diploid cell (WI-38) nuclei labeled with 3H-thymidine of moderate specific activity were obtained in 12 hr. Without scintillator the exposure time was 4 days. Exposure time for cells labeled with 125I-serum was reduced from over 90 days to 14 days. The shortened exposure time for banded chromosomes permitted successful prestaining with Giemsa, a sequence that is not possible without scintillator.