Biological Damage from Intranuclear Tritium: DNA Strand Breaks and Their Repair

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Science  15 Sep 1972:
Vol. 177, Issue 4053, pp. 996-998
DOI: 10.1126/science.177.4053.996


Isotopic decay in tritiated thymidine in the DNA of frozen (-196°C) Chinese hamster cells causes breaks in DNA strands to accumulate at a rate of 2.1 breaks per decay. After DNA is thawed the tritium-induced breaks repair rapidly with a half-time of 15 minutes at 37°C. In comparison to breakage by x-rays, the efficiency of DNA strand breakage by tritium is equivalent to 0.48 rad per decay. This dose per decay is close to that predicted by simple dosimetric considerations (0.38 rad per decay) for irradiation by the β particles from tritium.