title: Molecular imaging based on x-ray fluorescent high-Z tracers.
abstract: 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 mm(2), 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.
authors.affiliation: Helmholtz Zentrum München, Department for Medical Radiation Physics and Diagnostics, Ingolstädter Landstraße 1, Neuherberg, Germany.
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Müller
authors.forename: Christoph
authors.initials: C
authors.lastname: Hoeschen
authors.forename: Florian
authors.initials: F
authors.lastname: Grüner
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Arkadiev
authors.forename: Thorsten R C
authors.initials: TR
authors.lastname: Johnson
mesh_terms: D057054:Molecular Imaging / Q000379:methods*; D009010:Monte Carlo Method; D061848:Optical Imaging / Q000379:methods*; D014965:X-Rays