Dose to the shielded thymic region of irradiated mouse cadavers.

Frozen mouse cadavers were exposed to 220 kV roentgen irradiation with the thymic area covered with a lead plate sized 18 mm X 24 mm X 4 mm oe 18 mm X 12 mm X 4 mm. Lif-Telfon rods were used for dose measurements. With larger plate the mean dose from scattered radiation, in percent of that in the uprotected abdomen, was 12.77 (thymic lobes) and 18.34 (vertebra). With the smaller shield the figures were markedly increased, 16.70 and 23.77, respectively. Since the percentage dose is relatively high, the amount of scattered radiation may have biologic significance.