SU-D-217A-01: A High-Resolution in Vivo Molecular Imaging Technique Based on X- Ray Fluorescence

Traditional molecular imaging techniques such as PET/SPECT have many limitations, including relatively low spatial resolution, short lifetime of radioisotope probes, limited availability due to reliance on cyclotron, relatively high dose, and lack of effective molecular probes for certain tumor cells. In this work we demonstrate the feasibility of a novel x- ray fluorescence molecular imaging (XFMI) technique using high-power carbon nanotube (CNT) x-ray array technology. The XFMI overcomes some limitations and will be a significant advance in molecular imaging technology for cancer drug development and cancer biology research.

A testing chamber was constructed containing two Amptek energy-resolving detectors analyzing a copper collimated fluorescence beam placed opposite each other symmetric about the sample and perpendicular to the primary incoming x-ray beam, also using the copper collimator. Different concentrations of indium trichloride and iodine were tested to determine the minimum detectable concentration (MDC) for each.

The MDC for indium was found to be 80 ug/mL and 100 ug/mL for iodine at 50 kVp, 30mAs (5 minutes imaging time). This is on the order of magnitude of the MDCs determined at large synchrotron facilities using XFI. Higher concentrations above 1mg/mL of both elements were detectable at 1.5 mAs (15 seconds).

These results show that it is possible to not only measure low concentrations of the above elements, but also distinguish between similar L-alpha peaks. This allows for future work of obtaining 2D and 3D imaging to determine element types and concentrations diffused in different parts of the body. Carolina Center of Cancer Nanotechnology, University Cancer Research Fund.