Accession Number : ADA117304

Title :   Biologic Dosimetry for Nuclear Environments by Electron Paramagnetic Resonance (EPR) Methods.

Descriptive Note : Conference paper,

Corporate Author : ARMED FORCES RADIOBIOLOGY RESEARCH INST BETHESDA MD

Personal Author(s) : McCreery,Michael J. ; Swenberg,Charles E. ; Basso,Michael J. ; Conklin,James J. ; Hsieh,Jen-Shu

Report Date : 18 JUN 1982

Pagination or Media Count : 14

Abstract : A number of stable and unstable free radicals are produced by exposure of calcified tissues to ionizing radiation. Identification of the exact molecular nature of these radicals and their kinetic annealing properties awaits further investigation. However, the high stability and the dose-response characteristics of the signal at g = 2.0023 make it very promising for use in biologic dosimetry. A 10-25 mg sample of enamel is enough to determine absorbed from 10-10 to the 7th power rads of gamma, X-ray, and accelerated electron exposures. This sample, which is no more than a chip from the ridge of a human tooth, does not expose the living portion of the tooth and so is relatively noninvasive. Investigations to establish a standard method for this procedure and to evaluate neutron dose is in progress. Although the procedures outlined here are relatively noninvasive, this technique affords other approaches that are even less invasive. Unlike optical methods, the sample for EPR analysis does not have to be transparent. It is not even necessary to suspend the sample as a fine powder. As long as the bone or tooth sample is within the dimensional limits of the tuned EPR cavity, it can be analyzed intact. This fact makes in vivo analysis feasible. We are currently making attempts to enlarge the EPR cavity with modification of the corresponding electronic components so that a finger can be analyzed. If this approach is successful, the expedient evaluation of large numbers of casualties might be possible by a method that is noninvasive and nondestructive.

Descriptors :   *Dosimetry, *Radiation absorption, *Radiation monitors, Electron paramagnetic resonance, Biological absorption, Teeth, Bones, Radiation dosage

Subject Categories : Radiobiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE