Monte Carlo simulation of x-ray fluorescence analysis of gold in kidney using ~(99m)Tc radiopharmaceutical

摘要

The objective of this study was to design a system in order to analyze gold and other heavy elements in internal organs using in vivo x-ray fluorescence (XRF) analysis. Monte Carlo N Particle code MCNP was used to simulate phantoms and sources. A source of ~(99m)Tc was simulated in kidney to excite the gold x-rays. Changes in K XRF response due to variations in tissue thickness overlying the kidney at the measurement site were investigated. Different simulations having tissue thicknesses of 20,30,40,50 and 60 mm were performed. K_(α1) and K_(α2) for all depths were measured. The linearity of the XRF system was also studied by increasing the gold concentration in the kidney phantom from 0 to 500 μg g~(-1) kidney tissue. The results show that gold concentration between 3 and 10 μg g~(-1) kidney tissue can be detected for distance between the skin and the kidney surface of 20-60 mm. The study also made a comparison between the skin doses for the source outside and inside the phantom.