RI投与動物からの¹²⁵Iの空気中への飛散

抄録

Few reports were published on exhalation of a radioactive substance into the air from animals injected with it. For safe handling of iodine-125 in research using animals, we examined daily changes of airborne release of radioactivity from housing cages, containing mice treated with Na ¹²⁵I or ¹²⁵I labelled anti-mouse monoclonal IgG₁κ. Airborne radioactivity was collected during 100 min with a flow rate of 10l/min with charcoal filters and measured every 24 h during the period of 4 days. Radioactivity in the removed organs was also measured after 96 h of the time when the mice were sacrificed. Different patterns were observed in airborne radioactivity for different chemical forms of injected radioisotope, i.e. Na¹²⁵I or ¹²⁵I labelled anti-mouse monoclonal IgG₁κ. For Na ¹²⁵I injection, the radioactive concentration in air was highest at 24 h after injection. The concentration decreased gradually from 24 to 96 h, to one seventh at 96 h. Contrary, in the ¹²⁵I labelled anti-mouse monoclonal IgG₁κ injection, the radioactivity was low at 24 h and became highest at 96 h. The radioactivity only in the thyroid gland was higher in the Na ¹²⁵I than in ¹²⁵I labelled anti-mouse monoclonal IgG₁ κ injection. The radioactivity in the submaxillary gland, liver, kidney, stomach and lung was higher in the ¹²⁵I labelled anti-mouse monoclonal IgG₁κ than in Na ¹²⁵I injection. These results indicate that the different chemical forms of ¹²⁵I compounds show different patterns not only in the distribution in the organs but also in the exhalation.