Evaluation of the in vivo performance of a 109cd-based x-ray fluorescence system for measurement of skin iron concentration

There are many diseases associated with iron deficiency and iron overload prevalent in the Canadian population, however, there are no rapid, cost-effective, non-invasive methods of measuring iron. X-ray fluorescence (XRF) is a non-invasive means of quantifying iron in the body. Here we present the results from a preliminaryin vivomeasurement study using a novel¹⁰⁹Cd-based XRF system for the measurement of skin iron.In vivoXRF measurements of the thenar eminence of the hand were performed on 12 female and 12 male participants between 18 and 76 years of age. Participants had no known iron-associated diseases. The mean (median)in vivomeasurement uncertainty was 2.0µg Fe g^-1resulting in anin vivodetection limit of 4.0 (4.0)µg Fe g^-1, with a 95% confidence upper interval of 4.2µg Fe g^-1. The mean (median) estimate of skin iron was 9.0 (9.1)µg Fe g^-1with a range of 3-17µg Fe g^-1, matching reported levels in the literature. Iron concentrations were correlated with age (p= 0.019,R²= 0.19) with iron increasing by 2 ±1% per annum.Individual estimates of iron skin content were all greater than zero at the 95% confidence level. No differences in measurement uncertainty were observed across age and gender (p> 0.05). However, the increase in skin iron with age meant there was greater confidence that iron levels were greater than zero in older adults. The¹⁰⁹Cd K XRF system was therefore found to be feasible forin vivomeasurement of skin iron in this small population of healthy adults.