Normalisation with coherent scatter signal: improvements in the calibration procedure of the 57Co-based in vivo XRF bone-Pb measurement.
The feasibility of a normalised calibration variable to account for interpatient variability for in vivo 57Co XRF (X-ray fluorescence) finger bone-lead measurements was assessed. Normalising the lead X-ray intensities to the coherent scatter signal was investigated by experiment and Monte Carlo simulation. The X-ray to coherent ratios for a fixed lead concentration were within 5-10% of the mean, within uncertainty, over a physiologically relevant range of finger bone sizes and overlying tissue thicknesses. This is an acceptable level of variation to introduce, as it is less than the uncertainty of a typical in vivo measurement. Normalisation has several advantages compared with the current method of correcting for interpatient variation, as it eliminates the need for transporting extensive equipment to on-site measurements, reduces the subject dose by a factor of two, and increases the objectivity of the bone-Pb assessment.
O'Meara
J M
JM
Department of Physics and Astronomy, McMaster University, Hamilton, ON., Canada.
Börjesson
J
J
Chettle
D R
DR
Mattsson
S
S
D001842:Bone and Bones / Q000737:chemistry*; D003037:Cobalt Radioisotopes; D006801:Humans; D007854:Lead / Q000032:analysis*; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D012542:Scattering, Radiation; D013052:Spectrometry, X-Ray Emission / Q000295:instrumentation / Q000379:methods*
D003037:Cobalt Radioisotopes; D007854:Lead