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EVALUATION OF THE UNCERTAINTIES ASSOCIATED WITH IN VIVO X-RAY FLUORESCENCE BONE LEAD CALIBRATIONS

LODWICK, JEFFREY CLARK
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060197045

Abstract Details

2003, PhD, University of Cincinnati, Medicine : Environmental Health Sciences.
An anthropometric leg phantom developed at the University of Cincinnati (UC) was used to evaluate the effects that changes in leg position and variation between subjects has on in vivo x-ray fluorescence (XRF) measurements of stable lead in bone. The changes in leg position that were evaluated include changes in source-phantom distance ranging between 0.0 mm and 30.0 mm and phantom rotation over 40 degrees. Source-phantom distance was determined to have a significant effect on XRF measurement results particularly at source-phantom distances greater than 10.0 mm. Rotation of the leg phantom through 40 degrees was determined to have no significant effect on XRF measurement results. Between subject factors that were evaluated include bone calcium content and overlying tissue thickness. Bone calcium content was determined to have a significant effect on XRF measurements when measuring lead in micrograms per gram bone material. However, if measurement results of micrograms of lead per gram calcium (or per gram bone mineral) is used the normalization method makes the change in calcium content not significant. Overlying tissue thickness was determined to have no significant effect on XRF measurement results with tissue thickness ranging between 5.7 and 11.62 mm. The UC leg phantom was modified to include a fibula bone phantom so that the effect that the fibula has on XRF measurement results could be evaluated. The fibula was determined to have no significant effect on XRF measurement results and in the future need not be incorporated into in vivo XRF calibration phantoms. A knee phantom was also developed for purposes of calibrations of in vivo XRF measurement of lead in the patella. XRF measurement results using this phantom were compared to results of XRF measurements made using the plaster-of-Paris (POP) phantoms. A significant difference was observed between the normalized count rates of the two phantom types when either micrograms of lead per gram of bone material or micrograms of lead per gram calcium (bone mineral) is used as the lead content. This difference is consistent with what is observed in real in vivo XRF measurements and indicates the need for the correction factors that are used.
Dr. C. Scott Clark (Advisor)
142 p.
lead; x-ray fluorescence; phantom; bone

Recommended Citations

Citations

  • LODWICK, J. C. (2003). EVALUATION OF THE UNCERTAINTIES ASSOCIATED WITH IN VIVO X-RAY FLUORESCENCE BONE LEAD CALIBRATIONS [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060197045

    APA Style (7th edition)

  • LODWICK, JEFFREY. EVALUATION OF THE UNCERTAINTIES ASSOCIATED WITH IN VIVO X-RAY FLUORESCENCE BONE LEAD CALIBRATIONS. 2003. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060197045.

    MLA Style (8th edition)

  • LODWICK, JEFFREY. "EVALUATION OF THE UNCERTAINTIES ASSOCIATED WITH IN VIVO X-RAY FLUORESCENCE BONE LEAD CALIBRATIONS." Doctoral dissertation, University of Cincinnati, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060197045

    Chicago Manual of Style (17th edition)

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© 2003, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.