An enhanced sensitivity K-shell x-ray fluorescence technique for tibial lead determination

Area of Science:

• Medical Physics
• Biomedical Engineering
• Radiological Science

Background:

• Accurate measurement of tibial lead content is crucial for assessing lead exposure.
• K-shell X-ray fluorescence (XRF) is a common method for in vivo lead detection.
• Existing XRF systems face limitations in sensitivity, measurement time, and source activity.

Purpose of the Study:

• To describe a novel irradiation-detection geometry for enhanced sensitivity in tibial lead content measurement using K-shell XRF.
• To evaluate the performance of this new system in terms of precision, source activity, and measurement time.

Main Methods:

• Development of a high-count-rate system with a small-area high-specific-activity 109Cd source and a large-area uncollimated detector.
• Axially symmetric back-scattering arrangement for irradiation and detection.
• Study conducted on a cohort of 63 controls and 73 industrially exposed workers.

Main Results:

• Achieved precisions ranging from +/- 4.9 to +/- 14.2 micrograms Pb (g bone mineral)-1.
• Comparable precisions to earlier systems but with less than 50% source activity and 30% less measurement time.
• Investigated detector collimation, finding marginal energy resolution improvement but insignificant sensitivity change.

Conclusions:

• The novel geometry enhances sensitivity for tibial lead measurement using XRF.
• The system offers significant reductions in source activity and measurement time.
• Higher-count-rate detector systems show potential for achieving mean precisions down to +/- 3 micrograms Pb (g bone mineral)-1.