Dr. Euler (Cat) and friends,

It has been reported that the concentration of particulate matter like ceramic-uranium dioxide deposits much higher radiation dose to tissues where it is localized in tissues in an organ like the lungs than the average dose calculated for the whole organ. For example, Pb-210 cum Bi-210 cum Po-210 from tobacco leaves gets localized in tar material in upper bifurcation of the lungs. It deposits much higher radiation dose in that part of the lungs than that calculated for the entire lungs. The International Commission of Radiological Protection (ICRP) has also reported that tumors are found near the place where insoluble radioactive isotopes are accumulated in an organ. The lymph nodes often have ten times the concentration that is found in the lungs if the contamionants are inhaled as insoluble dust. Therefore the risk factors derived for fatal cancers in population exposed to the insoluble uranium dioxide on the basis of organ dose are bound to be somewhat lower. I am glad that Dr. Goodhead has brought forth this factor. Unfortunately, radiation biology in this area is in its infancy.

We should be collecting good set of epidemiologic data when drawing some conclusions for the clusters of leukemia found among army personnel that were deployed in Kosovo. A protocol for investigating the cause of clusters of leukemia among Italian army personnel and other army personnel belonging to other European countries should be outlined and a proper study should be conducted by a group of scientists who have outstanding credentials as soon as possible. There is a possibility that such clusters occur in general population. If some ammunition is found to cause leukemia, it will help some or all countries may consider banning it. We have to behave in a humane manner even though we have occasional armed conflicts.

Hari Sharma.