The microdistribution of alpha-active nuclides in the human lung

Abstract

New and elaborate techniques for α-particle spectroscopy and autoradiography based on the nuclear track detector CR-39 are being applied in a continuing study of α-emitting particles in the human lung. A great deal of new scientific information is emerging. It is important to establish the levels present in the general population as this serves as a baseline from which all abnormal levels, such as may be present in the lungs of underground miners and workers exposed to plutonium, may be compared. The determination of the absolute abundance of nuclides at a given site is particularly important. This information may be used to plot the mechanisms at work in lung for the clearance of insoluble particles and to identify long term retention sites. In the data obtained to date up to 60% of the activity takes the form of multiple decays, from single points over a period of ∼ 100 days which is comparable with the division rate of sensitive cells in the lung. This observation is of fundamental importance to the estimation of the natural mutation rate from α-activity of cells in lung. The paper will discuss examples of the results from this work.