Multi-element analysis of the human body using neutron activation

Area of Science:

• Nuclear medicine
• Medical physics
• Biomedical engineering

Background:

• Accurate measurement of total body elemental composition is crucial for assessing nutritional status and disease progression.
• In vivo neutron activation analysis (NAA) offers a non-invasive method for quantifying major elements in the human body.

Purpose of the Study:

• To describe the calibration of the Leeds in vivo neutron activation facility for simultaneous measurement of total body Na, Cl, P, Ca, N, and K.
• To incorporate the effects of body size and shape using a variable anthropomorphic phantom.
• To detail the correction methods for interfering nuclear reactions and determine the accuracy and precision of the technique.

Main Methods:

• Calibration of the Leeds in vivo NAA facility.
• Utilized a variable anthropomorphic phantom to account for body size and shape variations.
• Applied corrections for main interfering nuclear reactions.
• Determined accuracy and precision of the elemental measurements.

Main Results:

• The facility allows simultaneous measurement of total body Na, Cl, P, Ca, N, and K.
• Nitrogen (N) was measured with a coefficient of variation (CV) of 2.2% at 0.5 mSv dose equivalent.
• Potassium (K) was measured with a CV of 1.6% in the same counting period.
• Sodium (Na), Chlorine (Cl), and Phosphorus (P) were determined with CVs of 2.2%, 1.6%, and 2.9% respectively at 5 mSv.
• Calcium (Ca) was measured with a CV of 3% at 10 mSv dose equivalent.

Conclusions:

• The described calibration procedure is suitable for measuring elemental composition in critically ill patients.
• The technique provides accurate and precise measurements of total body elements with acceptable radiation doses.
• The method is advantageous as both irradiation and counting are performed with the patient in a supine position.