X-Ray Fluorescence Measurements of Iron in the Skin Using a CD-109-Based System

Abstract

Iron conditions can range from iron deficiency to iron overload. It is vital to accurately monitor iron levels so patients can receive proper treatment to reduce potential consequences such as organ failure. Current methods of measuring iron include blood tests and liver biopsies, both of which are invasive.

This work investigates the feasibility of using x-ray fluorescence (XRF) techniques to non-invasively measure iron in the body. The device employed for this work uses Cd-109 as the excitation source for XRF. Previously, this device had only been used to measure iron phantoms and ex vivo pig and rat skin samples. This thesis explores the use of this device for in vivo measurements.

Optimization and calibration of the device was completed to determine the optimal setup for in vivo measurements. A hand holder jig was designed and 3D-printed to secure participant hands for 1200-second measurements. 24 participants were recruited for this study who had no known iron diseases. 12 female and 12 male participants in the age range of 18 to 76 were measured. The average iron concentration was 9.1 ppm with a measurement uncertainty of 2.0 ppm. Importantly, the uncertainty in the in vivo measurements were similar to the uncertainty of phantom measurements, which suggests that human variations in hand size, position, and movement did not worsen measurement precision. No statistically significant differences were observed across age and gender (p>0.05), suggesting that these factors do not affect measurement precision. Analysis of measurement uncertainties demonstrate that in vivo measurements are feasible with a 95% confidence level for measurements above 4.0 ppm.

This research points towards the feasibility of using this Cd–109-based XRF device for in vivo measurements of iron. Further work is required to investigate the accuracy and validity of this device through comparison to currently accepted measurement methods.