The DNA content of some mammalian cells measured by flow cytometry and its influence on radiation sensitivity.

The DNA content of nine mammalian cell lines was determined by flow cytometry. Using radiobiological data from this and other laboratories a correlation between DNA mass and 1/D0 for X-rays, alpha-particles, and heavy ions could be established when the quantities were plotted on a log-log scale. The slopes of the regression lines amounted to 0.65 (X-rays), 0.64 (alpha-particles) and 0.74 (heavy ions). A similar correlation was found between DNA content and mean inactivation dose. The rather uniform slopes close to 2/3 suggest that radiosensitivity may depend on the surface area of the sensitive target, (cell nucleus) indicating a possible non-uniform distribution of radiosensitive sites within the nucleus.