Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/2006
Publication Date: 4/3/2006
Citation: Shypailo, R.J., Ellis, K.J. 2006. Prompt-gamma neutron activation analysis system design: Effects of D-T versus D-D neutron generator source selection [abstract]. 7th International Conference on Methods of Applications of Radioanalytical Chemistry. Abstract No. 113. Interpretive Summary:
Technical Abstract: Prompt-gamma neutron activation analysis (PGNAA) is used for the non-invasive measurement of human body composition. Advancements in portable, compact neutron generator design have made those devices attractive as neutron sources. Two distinct generators are available: D-D with 2.5 MeV, and D-T with 14.2 MeV neutrons. To compare the performance of these two units in our present PGNAA system, we performed Monte Carlo simulations (MCNP-4B2; Los Alamos National Laboratory) evaluating the nitrogen reactions produced in tissue-equivalent phantoms and the effects of background interference on the gamma detectors. Experimental measurements using phantoms were obtained as verification of the Monte Carlo predictions for counting precision and measurement sensitivity. Monte Carlo response curves showed increased gamma production per unit dose when using the D-D generator, suggesting that it is the more suitable choice for smaller sized subjects. However, nonuniform signal production within the irradiated body region may necessitate shielding and/or collimator design changes. The increased penetration by higher energy neutrons produced by the D-T generator supports its utility when examining larger, especially obese, subjects. A clinical PGNAA design incorporating both neutron generator options may be the best choice for a system required to measure a wide range of subject phenotypes.