Survival of Mouse Type B Spermatogonia for the Study of the Biological Effectiveness of 1 MeV, 2·3 MeV and 5·6 MeV Fast Neutrons

Summary

The most radiation-sensitive cells in the testis are B and intermediate spermatogonia. We have used a histological scoring technique to compare three neutron beams of different mean energies (1 MeV at the ECN, Petten, 2·3 MeV at the Gray Laboratory, Northwood, and 5·6 MeV at the Oncological Centre, Krakow).

CBA inbred mice, 14–20 weeks old, were exposed to whole-body irradiation with single doses of either X-rays (0·1–1 Gy) or neutrons (0·2–0·25 Gy).

Relative biological effectiveness values, calculated at the level of 50 per cent reduction in survival of B spermatogonia, were 5·7 at the ECN, Petten, 4·6 at the Gray Laboratory and 3·0 at the Oncological Centre in Krakow. The D_o value for the B spermatogonia after X-rays was 0·34 ± 0·02 Gy when the data from the three centres were combined. D_o values for neutrons for the examined spermatogonia were 0·08 Gy, 0·09 Gy and 0·11 Gy at the ECN, Petten, the Gray Laboratory and the Oncological Centre, respectively.