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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #66630
Title: A MODULAR DISTRIBUTED WHOLE BODY COUNTER PHANTOM ("FUZZY"). II. MEASUREMENTS

Author
item LIQIANG, TAO - UND
item LYKKEN, GLENN - UND
item MOMCILOVIC, BERISLAV - UNIV OF ZAGREB

Submitted to: North Dakota Academy of Science Proceedings
Publication Type: Other
Publication Acceptance Date: 4/25/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: The essential prerequisite for any accurate measurement of radioactivity is to have an appropriate dose, size, and shape standard to match the sample. The large size of the human body and its complex 3D geometry makes the accurate measurement of radioactivity in human whole body counters (HWBC) a formidable task. The problem is even more complex when it comes to the accurate assessment radioactivity at specific regions of the body because there is no adequate method to relate such regional counts to the whole body counts in a quantitative way. Thus, based on how the multiple detector crystals apparently "see" a standard was constructed which would allow the accurate assessment of regional activity. The single source of radioactivity was divided into 12 separate parts (modulos) each containing the same amount of radioactivity in a way to outline the contour of the human body. The HWBC read the "fuzzy" as a uniform source where each part of the standard contributed equally to the total. The uniformity of the "fuzzy" modulos allowed the accurate quantification of regional radioactivity.

Technical Abstract: A human whole body counter (HWBC) is a device that measures radiation emitted from the human body. With the HWBC at the Grand Forks Human Nutrition Research Center, up to 32 radiation detectors, 16 above and 16 below a subject's bed, can be utilized to measure this radiation. The total radiation detected by the HWBC depends upon the location of the radioactivity in the body and upon body shape and size. The object of this experiment was to construct a radically different human body model (FUZZY phantom) that would allow the determination of the contribution of specific regional body radiation sources (organs) to the total body radiation measured by the 32 detectors. A FUZZY phantom with 75 0.775 liter containers (12 contained radioactive solutions in water, 63 contained water only), in a 5 x 15 checkerboard pattern was used to show that the contribution to the total radiation measured was nearly independent of body location. Thus, individual organ detectors can be used to measure localized activities. This will allow the determination in various body parts of tracer doses of radioisotopes of mineral nutrients which will allow for establishing where these minerals are needed.