Cell death induced by tritiated water in mouse intestine studied in a new tritium safety clean cabinet

Tritiated water (HTO) was injected intraperitoneally into 10 week old mice, the activity per mouse ranging from 3.7 to 106 Bq (0.1 mCi) to 3.7 x 109 Bq (100 mCi). The mice were killed 3 to 24 hours later, and dead cells in the crypts of the small intestine were counted. For those mice given 1.85 x 107 Bq (0.5 mCi) or more, an increased incidence of cell death with increasing time was observed within 3-9 h after injection. The data for 3.7 x 106 Bq (0.1 mCi) per mouse were similar to those for the untreated control mice. Six hours after injection, the activity-response relationship for cell death was determined. The D0 value was calculated to be 0.2 Gy (20 rad). When this was compared with the D0 for the cell death induced by continuous irradiation with 137Cs gamma rays, the RBE of HTO was 1.6. (author)