Skip to main content
ARS Home » Plains Area » Houston, Texas » Children's Nutrition Research Center » Research » Publications at this Location » Publication #81187
Title: TOTAL BODY CHLORINE MEASUREMENTS BASED ON THE 5.6, 6.1, AND 8.6 MEV PEAKS IN IN VIVO PROMPT-GAMMA NEUTRON ACTIVATION ANALYSIS

Author
item SHYPAILO, ROMAN - BAYLOR COLL OF MEDICINE
item Ellis, Kenneth

Submitted to: Journal of Radioanalytical and Nuclear Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Total body chlorine can provide an estimate of extracellular water, which can help determine an individual's fluid balance in regard to certain disease states. Our research center has a prompt-gamma neutron activation analyzer that has been used with living human subjects to measure total body nitrogen, which is useful in body composition and other scientific studies. Previous studies have determined that prompt- versus delayed-gamma neutron activation analyses provide accurate results with a lower radiation dose, lower cost, and greater convenience for the subject. We wanted to know if the prompt-gamma machine could be used to measure total body chlorine as well. We used a phantom containing a chlorine solution to provide activations on which we based our machine's calibration, and analyzed the peaks to determine total body chlorine precision. Preliminary analyses of the prompt-gamma range for 33 females aged 24 to 40 years provided a mean estimate of 0.85 grams of chlorine per kilogram body weight. Our results support this use of this machine to obtain accurate measurement of total body chlorine concurrent with body nitrogen measurement.

Technical Abstract: Total body chlorine (TBC1) provides an estimate of extracellular water, and has been measured using delay-gamma neutron activation at a dose >3 mSv. We have examined the feasibility of measuring TBC1 using the 5.6, 6.1, and 8.6 MeV C1 peaks produced during in vivo prompt-gamma neutron activation (dose <0.3 mSv). This facility consists of a bed which moves over a shielded, collimated 241Am,Be neutron source and four shielded NaI(T1) detectors. Calibration was based on 1800-sec activations using an anthropomorphic phantom containing a C1-based solution. Peaks were analyzed individually and in combinations to determine TBC1 precision. At human physiological levels, precision ranged from 1.6% to 3.7% for different combinations of the three C1 peaks. In subjects, background interference permitted the use of only the 8.6 MeV peak in C1 analysis. Preliminary analyses of the prompt-gamma spectra for 33 healthy females (ages: 24-40 yr) provided a mean estimate of 0.85 g C1 per kg body weight. It is therefore feasible to measure TBC1 concurrently with body nitrogen using relatively low-dose prompt-gamma neutron activation analysis.