Experimental demonstration of benchtop x-ray fluorescence computed tomography (XFCT) of gold nanoparticle-loaded objects using lead- and tin-filtered polychromatic cone-beams

Abstract

This report presents the first experimental demonstration, to our knowledge, of benchtop polychromatic cone-beam x-ray fluorescence computed tomography (XFCT) for a simultaneous determination of the spatial distribution and amount of gold nanoparticles (GNPs) within small-animal-sized objects. The current benchtop experimental setup successfully produced XFCT images accurately showing the regions containing small amount of GNPs (on the order of 0.1 mg) within a 3-cm diameter plastic phantom. In particular, the performance of the current XFCT setup was improved remarkably (e.g., at least a factor of 3 reduction in XFCT scan time) using a tin-filtered polychromatic beam in comparison with a lead-filtered beam. The results of this study strongly suggest the current benchtop XFCT configuration can be made practical with a few modifications such as the deployment of array detectors, while meeting realistic constraints on x-ray dose, scan time, and image resolution for routine pre-clinical in-vivo imaging with GNPs.

Improving x‐ray fluorescence signal for benchtop polychromatic cone‐beam x‐ray fluorescence computed tomography by incident x‐ray spectrum optimization: A Monte Carlo study

“…While monochromatic x-rays are considered ideal 5 for XFCT, the impracticality of using synchrotrons in typical biomedical laboratory settings, especially for in vivo imaging of small animals, has motivated the implementation of XFCT on a benchtop setting using a polychromatic diagnostic energy-range x-ray source (viz., "benchtop XFCT"). Through a series of studies, [6][7][8] we have shown that benchtop XFCT is capable of localizing gold nanoparticles (GNPs) inside small-animal-sized objects by detecting gold x-ray fluorescence (XRF) photons from GNPs. Especially, in our latest experimental study, 7 we demonstrated the capability of performing benchtop XFCT of GNPloaded objects using polychromatic cone-beams, paving the way to build a practical benchtop XFCT system.…”

“…Through a series of studies, [6][7][8] we have shown that benchtop XFCT is capable of localizing gold nanoparticles (GNPs) inside small-animal-sized objects by detecting gold x-ray fluorescence (XRF) photons from GNPs. Especially, in our latest experimental study, 7 we demonstrated the capability of performing benchtop XFCT of GNPloaded objects using polychromatic cone-beams, paving the way to build a practical benchtop XFCT system. Additionally, other researchers have applied similar benchtop XFCT techniques to image various other metal probes (e.g., platinum) within small-animal-sized phantoms, [9][10][11] suggesting the possibility of extending benchtop XFCT techniques beyond GNP applications.…”

Development of XFCT imaging strategy for monitoring the spatial distribution of platinum‐based chemodrugs: Instrumentation and phantom validation

“…The improvement can also be made in XFCT by using a cone beam geometry. 23 Future work includes optimizing the imaging geometry using a polarized x-ray source (to reduce the interference of scatter photons 17,19,24 ), and a pixelated CZT photon-counting detector panel (to shorten imaging time) with square-hole pixelated collimator. The spectrum and data analysis algorithms will also be improved.…”

Full-field fan-beam x-ray fluorescence computed tomography with a conventional x-ray tube and photon-counting detectors for fast nanoparticle bioimaging

“…Similar processes of shifting on detectors are also required for a fan-beam setup with a single pixel detector. 30 Jones and Cho 31 demonstrated the simulation results of XFCT using a polychromatic *Address all correspondence to: Liang Li, E-mail: lliang@tsinghua.edu.cn cone-beam source with detector arrays and indicated that the total scanning time can be significantly reduced. Cong et al 32 proposed a fan-beam XFCT setup with detector arrays and evaluated its feasibility through simulation.…”