Problems with irradiators.

In Japan, where all cell concentrates are irradiated because of an unusually high risk of transfusion-associated graft-versus-host disease (GVHD) due to the high percentage of HLA homozygous subjects in the population, there have been problems with the breakdown of IBL gamma irradiators. When an irradiator breaks down, it is often found to be difficult for the agencies, or even the manufacturers, to repair it. Furthermore, it seems to be difficult in Japan to obtain new irradiators. Finally, the US Nuclear Regulatory Commission Task force recommends the phase-out of Cs-137 irradiators in 2 years to prevent terrorists using the isotopes, though the bill is not likely to be submitted. Although in no other country all cell concentrates are irradiated, there are indications for irradiation in all of them. It seems therefore of interest to investigate whether there are similar problems outside Japan. To obtain information, the following questions were sent to the relevant authorities: