In-Vivo X-Ray Fluorescence Assessment of Iron Levels in the Skin for β-Thalassemia Patients

Abstract

<p>The purpose of this study is to assess the feasibility of a non-invasive, reliable, and cheap method to evaluate iron-overload in beta-thalassemia major patients. The approach taken was through the possibility of in-vivo measurement of iron in the skin using a technique called x-ray fluorescence. It was hoped that the quantification of iron levels in the skin will correlate with those levels in major parenchymal organs, such as the liver and the heart – where most iron deposition occurs in thalassemic patients. Water phantoms were used to produce a calibration line with an R² value of 0.998. Skin, liver and heart tissues from 36 control mice were measured and their iron levels quantified. Iron concentration range in the skin was found to be -2 – 38 ppm with an average of 9.8 ± 1.6 ppm. Significant correlation was found between the iron levels in skin vs. heart (R_s² of 0.382); however, it was not significant in skin vs. liver (R_s² of 0.080). Skin biopsies from various sites of 6 cadavers were investigated in a synchrotron light source facility. Maps of iron, zinc and calcium distribution as a function of skin depth were then constructed. It was found that all three elements were significantly present in the epidermal layer compared to the dermal one. Calcium and zinc were present in the entire epidermis, whereas iron was mainly concentrated at the deepest region of the epidermis. It was also concluded that skin samples from the back, arm and thigh gave the clearest elemental distribution.</p>