Molecular imaging based on x-ray fluorescent high-Z tracers

• Published in: Physics in medicine & biology 2013-11, Vol.58 (22), p.8063-8076
• Main Authors: Müller, Bernhard H, Hoeschen, Christoph, Grüner, Florian, Arkadiev, Vladimir A, Johnson, Thorsten R C
• Format: Article
• Language: English
• Subjects: Geant4 Monte Carlo simulation; gold nanoparticles; high-Z tracers; iodine; molecular imaging; Molecular Imaging - methods; Monte Carlo Method; Optical Imaging - methods; x-ray fluorescence; X-Rays
• ISSN: 0031-9155; 1361-6560
• DOI: 10.1088/0031-9155/58/22/8063

We propose a novel x-ray fluorescence imaging setup for the in vivo detection of high-Z tracer distributions. The main novel aspect is the use of an analyzer-based, energy-resolved detection method together with a radial, scatter reducing collimator. The aim of this work is to show the feasibility of this method by measuring the Bragg reflected K-fluorescence signal of an iodine solution sample in a proof of principle experiment and to estimate the potential of the complete imaging setup using a Monte Carlo simulation, including a quantification of the minimal detectable tracer concentration for in vivo imaging. The proof of principle experiment shows that even for a small detector area of approximately 7 mm2, the collimated and Bragg reflected K-fluorescence signal of a sample containing an iodine solution with a concentration of 50 µg ml−1 can be detected. The Monte Carlo simulation also shows that the proposed x-ray fluorescence imaging setup has the potential to image distributions of high-Z tracers in vivo at a radiation dose of a few mGy and at tracer concentrations down to 1 µg ml−1 for iodine in small animals.