Focused x-ray luminescence computed tomography: experimental studies

Abstract

X-ray luminescence computed tomography (XLCT) is an emerging hybrid molecular imaging modality and has shown great promises in overcoming the strong optical scattering in deep tissues. Though the narrow x-ray beam based XLCT imaging has been demonstrated to obtain high spatial resolution at depth, it suffers from a relatively long measurement time, hindering its practical applications. Recently, we have designed a focused x-ray beam based XLCT imaging system and have successfully performed imaging in about 7.5 seconds per section for a mouse sized object. However, its high spatial resolution capacity has not been fully implemented yet. In this paper, with a superfine focused x-ray beam we design a focused-x-ray luminescence tomography (FXLT) system for spatial resolution up to 94 μm. First, we have described our design in details. Then, we estimate the performance of the designed FXLT imaging system. Lastly, we have found that the spatial resolution of FXLT can be further improved by reducing the scan step size, which has been demonstrated by numerical simulations.

Method for improving the spatial resolution of narrow x-ray beam-based x-ray luminescence computed tomography imaging

“…According to previous studies, the spatial resolution limit of XLCT is generally believed to be determined by the beam aperture size. Therefore, generation of superfine x-ray beams, such as superfine collimated x-ray beams imaging 11 and focused x-ray beams imaging, 12 is generally thought to be the only way to improve the spatial resolution of XLCT imaging. However, both methods for generating superfine beams have their own shortcomings.…”

“…Since Pratx et al. reported for the first time that narrow-beam selective excitation-based XLCT imaging could image the distribution of phosphor particles, 1 – 3 various institutions have made many attempts to further develop and improve XLCT imaging by developing new imaging systems, 1 , 4 – 12 building robust reconstruction algorithms, 13 – 15 and designing efficient imaging probes. 16 – 20 …”

“…Another scanning mode is the narrow beam-based XLCT imaging, in which a collimated or focused x-ray beam is used to scan an object sequentially. 1 , 11 , 12 The narrow beam-based XLCT imaging can have a spatial resolution up to a fraction of a millimeter because the fine beam size can be applied for anatomical guidance in the XLCT reconstruction algorithm. 23 The disadvantage is its relatively long scanning time due to the small excitation region, although this can be addressed by using a higher sensitivity optical detector.…”

“… 23 The disadvantage is its relatively long scanning time due to the small excitation region, although this can be addressed by using a higher sensitivity optical detector. 10 , 12 …”