In vivo assessment of lung burdens at the Los Alamos National Laboratory

The Los Alamos National Laboratory program for in vivo measurements includes the capability for the assessment of plutonium and americium lung burdens. This capability is an important part of the health and safety program at Los Alamos where a wide variety of radioisotopes are utilized. This report addresses the lung burden assessment portion of our in vivo measurement capabilities. Lung burden measurements at Los Alamos make use of a twin phoswich detector system placed over the lungs of a prone subject. Analysis results are interpreted in terms of two basic statistical measures of detection limits. One measure is called the minimum significant measured activity (MSMA), which is interpreted as meaning that there is some activity in the lungs. The second measure is called the minimum detectable true activity (MDTA), which is defined as the smallest amount of activity required to be in the lungs in order that a measurement of an individual can be expected to imply, correctly, the presence of activity with a predetermined degree of confidence