Liqiang Tao

Date of Award

4-24-1998

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics & Astrophysics

First Advisor

Glenn I. Lykken

Abstract

"Fuzzy" is the radically new whole-body counter phantom concept that is based on how the human whole-body counter (HWBC) "sees" the inhomogeneous radionuclide distribution within the 3D shape of the human body. "Fuzzy" is used in conjunction with locally placed external detectors. "Fuzzy" is placed on a plastic board 1.91 m long and 0.64 m wide that is divided into 75 equal squares (163 cm$\sp2$ each) which are organized in five columns (A-E) and fifteen rows from head to toe (1-15). To comply with the two fold symmetry of the human body, "Fuzzy" is divided by the Golden section (37.5% as measured from the cranial side) to match with the position of human umbilicus. A radio-active source containing 1.2$\mu$Ci$\sp{65}$Zn was divided into 12 equal activities and distributed in conical cups (height, 9.5 cm, bottom diameter d$\sb1$ = 9.0 cm; top diameter d$\sb2$ = 11.0 cm) containing 0.50L of radioactive solution and placed in positions C1, B3, D3, C4, B5, D5, C6, B7, D7, C9, C10, and C12 which vaguely outlines the contour of the human body. The other positions were filled with identical cups containing SuperQ water only. The "Fuzzy" behaved (1) linearly in the HWBC when $\sp{65}$Zn cups were, sequentially, either added or removed from the board, and (2) homogeneously, i.e., it gave the same number of counts when any single site-specific $\sp{65}$Zn cup was substituted with a cup containing SuperQ water only. The USDA, ARS, Grand Forks Human Nutrition Research Center HWBC consists of two 16-detector beds, each of which provides 0.4 x 2.0 m$\sp2$ of detector surface. Evidently, the HWBC "sees" the "Fuzzy" as a uniform radiation source. This allows for the simultaneous use of the same "Fuzzy" phantom as a calibration standard for the external detectors and hence quantitative assessment of the regional activity.

Download

Share

COinS