First experimental result with fluorescent X‐ray CT based on sheet‐beam geometry

Abstract

Fluorescent X‐ray computed tomography (FXCT) enables us to reveal the cross‐sectional distribution of very low concentration of specific elements, e.g. I, Gd, or Au, in biomedical samples at a spatial resolution of several hundred micrometers, and it has been used to evaluate the states of cerebral perfusion and fatty acid metabolic function of small animals in vivo and ex vivo. However, since the current system employs the data‐acquisition scheme of the first‐generation type of CT, it requires a huge amount of time to obtain a whole set of projections. In order to overcome the problem, we propose a novel imaging geometry using a sheet incident beam. We performed a proof‐of‐concept experiment using a preliminary imaging system constructed at beam line BLNE‐5A, KEK. The efficacy of the proposed method is demonstrated by the reconstructed images of a physical phantom containing various concentrations of iodine solution and a mouse brain that is extracted after intravenous injection of 127I‐IMP for observing the cerebral perfusion and then fixed with formalin. Copyright © 2009 John Wiley & Sons, Ltd.

Advances in functional X-ray imaging techniques and contrast agents

“…New developments in spectral imaging cameras are expected to greatly improve sensitivity and acquisition speed. 133, 201, 209 …”

Fast and accurate X-ray fluorescence computed tomography imaging with the ordered-subsets expectation maximization algorithm

“…Therefore, we can conclude that the imaging efficiency of XFCT could be greatly improved by the introduction of OSEM. Combined with the new data-acquisition mode (Huo et al, 2009), OSEM-based XFCT has the potential to become a routine X-ray fluorescence CT imaging method and find broad applications in many fields.…”

“…To solve this problem a number of detector elements were adopted (McNear Jr et al, 2005) to decrease the collection time of each spectrum by expanding the solid angle. A new data acquisition mode (Huo et al, 2009) was proposed to accelerate the image acquisition. In the new mode a sheet beam was used, and few translations were needed at each sampling angle.…”

Experimental demonstration of novel imaging geometries for x‐ray fluorescence computed tomography

“…The groups pursuing in vivo implementations of XFCT have explored the use of new geometries that offer improvements over the first generation geometry in regimes where micrometer-scale resolution is not required. Huo et al 31 used a sheet beam to illuminate an entire slice at once and placed a 1D array of collimated detectors at 90 • to the beam. The array of detectors thus acquired a parallel-beam projection of the fluorescence emission.…”

“…The sample was then rotated and the process repeated to acquire additional views. They note that the use of a 1D array of collimated detectors, as in Huo 31 above, would eliminate the need for scanning and that a 2D collimated array would allow for simultaneous multislice acquisition.…”