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Li L, Zhang S, Zhang W, Lu H. Full-field in vivoimaging of nanoparticles using benchtop cone-beam XFCT system with pixelated photon counting detector. Phys Med Biol 2023; 68. [PMID: 36646060 DOI: 10.1088/1361-6560/acb3aa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/16/2023] [Indexed: 01/17/2023]
Abstract
Objective.X-ray fluorescence computed tomography (XFCT) is a promising noninvasive technique forin vivoimaging of high-Z elements (e.g. gadolinium (Gd) or gold (Au)). In this study we upgraded our experimental XFCT system using a flat panel photon counting detector with redesigned pinhole collimation in order to achieve 3D XFCT images during one scan.Approach.Aiming at the characteristics of pinhole-collimated cone-beam XFCT imaging, a new scatter correction algorithm was proposed to estimate the normalized spectrum of scatter background based on K-N formula and realize correction by a weighted least squares method. Then, images were quantitatively reconstructed by a maximum likelihood iterative algorithm with the attenuation correction.Main results.The potential on full-fieldin vivoXFCT imaging of this new system was investigated. An imaging experiment of a PMMA phantom with the diameter of 35 mm was carried out for quantitative evaluation of the system performance. Results show that 2 mg ml-1Gd solutions can be successfully reconstructed with a 45 min cone-beam XFCT scan.In vivoXFCT imaging experiments of mice with injection of Gd nanoparticles (GdNPs) were also performed and demonstrated in this paper. A mouse was injected through the tail vein with 20 mg ml-1NaGdF4 solution and then anesthetized with isoflurane during the cone-beam XFCT scan.Significance.The distribution of the GdNPs inside the mouse can be well reconstructed so that the deposition of NPsin vivocan be clearly observed, which indicates the feasibility of the proposed system for full-field XFCT of small animals and further potential in relevantin vivoresearch.
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Affiliation(s)
- Liang Li
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Key Laboratory of Particle and Radiation imaging (Tsinghua University), Ministry of Education, Beijing, 100084, People's Republic of China
| | - Siyuan Zhang
- Department of Engineering Physics, Tsinghua University, Beijing, 100084, People's Republic of China.,Key Laboratory of Particle and Radiation imaging (Tsinghua University), Ministry of Education, Beijing, 100084, People's Republic of China
| | - Wenli Zhang
- School of Biomedical Engineering, Air Force Medical University, Xi'an, 710000, People's Republic of China.,Shanxi Provincial Key Laboratory of Bioelectromagnetic Detection and Intelligent Perception, School of Biomedical Engineering, Air Force Medical University, Xi'an, 710000, People's Republic of China
| | - Hongbing Lu
- School of Biomedical Engineering, Air Force Medical University, Xi'an, 710000, People's Republic of China.,Shanxi Provincial Key Laboratory of Bioelectromagnetic Detection and Intelligent Perception, School of Biomedical Engineering, Air Force Medical University, Xi'an, 710000, People's Republic of China
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Kim T, Lee WS, Jeon M, Kim H, Eom M, Jung S, Im HJ, Ye SJ. Dual imaging modality of fluorescence and transmission X-rays for gold nanoparticle-injected living mice. Med Phys 2023; 50:529-539. [PMID: 36367111 DOI: 10.1002/mp.16070] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 10/12/2022] [Accepted: 10/14/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND X-ray fluorescence (XRF) imaging for metal nanoparticles (MNPs) is a promising molecular imaging modality that can determine dynamic biodistributions of MNPs. However, it has the limitation that it only provides functional information. PURPOSE In this study, we aim to show the feasibility of acquiring functional and anatomic information on the same platform by demonstrating a dual imaging modality of pinhole XRF and computed tomography (CT) for gold nanoparticle (GNP)-injected living mice. METHODS By installing a transmission CT detector in an existing pinhole XRF imaging system using a two-dimensional (2D) cadmium zinc telluride (CZT) gamma camera, XRF and CT images were acquired on the same platform. Due to the optimal X-ray spectra for XRF and CT image acquisition being different, XRF and CT imaging were performed by 140 and 50 kV X-rays, respectively. An amount of 40 mg GNPs (1.9 nm in diameter) suspended in 0.20 ml of phosphate-buffered saline were injected into the three BALB/c mice via a tail vein. Then, the kidney and tumor slices of mice were scanned at specific time points within 60 min to acquire time-lapse in vivo biodistributions of GNPs. XRF images were directly acquired without image reconstruction using a pinhole collimator and a 2D CZT gamma camera. Subsequently, CT images were acquired by performing CT scans. In order to confirm the validity of the functional information provided by the XRF image, the CT image was fused with the XRF image. After the XRF and CT scan, the mice were euthanized, and major organs (kidneys, tumor, liver, and spleen) were extracted. The ex vivo GNP concentrations of the extracted organs were measured by inductively coupled plasma mass spectrometry (ICP-MS) and L-shell XRF detection system using a silicon drift detector, then compared with the in vivo GNP concentrations measured by the pinhole XRF imaging system. RESULTS Time-lapse XRF images were directly acquired without rotation and translation of imaging objects within an acquisition time of 2 min per slice. Due to the short image acquisition time, the time-lapse in vivo biodistribution of GNPs was acquired in the organs of the mice. CT images were fused with the XRF images and successfully confirmed the validity of the XRF images. The difference in ex vivo GNP concentrations measured by the L-shell XRF detection system and ICP-MS was 0.0005-0.02% by the weight of gold (wt%). Notably, the in vivo and ex vivo GNP concentrations in the kidneys of three mice were comparable with a difference of 0.01-0.08 wt%. CONCLUSIONS A dual imaging modality of pinhole XRF and CT imaging system and L-shell XRF detection system were successfully developed. The developed systems are a promising modality for in vivo imaging and ex vivo quantification for preclinical studies using MNPs. In addition, we discussed further improvements for the routine preclinical applications of the systems.
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Affiliation(s)
- Taeyun Kim
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
| | - Woo Seung Lee
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
| | - Miyeon Jeon
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
| | - Hyejin Kim
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
| | - Mingi Eom
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea
| | - Seongmoon Jung
- Department of Radiation Oncology, Seoul National University Hospital, Seoul, South Korea
| | - Hyung-Jun Im
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea.,Research Institute for Convergence Science, Seoul National University, Seoul, South Korea
| | - Sung-Joon Ye
- Department of Applied Bioengineering, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, South Korea.,Research Institute for Convergence Science, Seoul National University, Seoul, South Korea.,Advanced Institute of Convergence Technology, Seoul National University, Suwon, South Korea.,Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea
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Warr R, Handschuh S, Glösmann M, Cernik RJ, Withers PJ. Quantifying multiple stain distributions in bioimaging by hyperspectral X-ray tomography. Sci Rep 2022; 12:21945. [PMID: 36535963 PMCID: PMC9763266 DOI: 10.1038/s41598-022-23592-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/02/2022] [Indexed: 12/23/2022] Open
Abstract
Chemical staining of biological specimens is commonly utilised to boost contrast in soft tissue structures, but unambiguous identification of staining location and distribution is difficult without confirmation of the elemental signature, especially for chemicals of similar density contrast. Hyperspectral X-ray computed tomography (XCT) enables the non-destructive identification, segmentation and mapping of elemental composition within a sample. With the availability of hundreds of narrow, high resolution (~ 1 keV) energy channels, the technique allows the simultaneous detection of multiple contrast agents across different tissue structures. Here we describe a hyperspectral imaging routine for distinguishing multiple chemical agents, regardless of contrast similarity. Using a set of elemental calibration phantoms, we perform a first instance of direct stain concentration measurement using spectral absorption edge markers. Applied to a set of double- and triple-stained biological specimens, the study analyses the extent of stain overlap and uptake regions for commonly used contrast markers. An improved understanding of stain concentration as a function of position, and the interaction between multiple stains, would help inform future studies on multi-staining procedures, as well as enable future exploration of heavy metal uptake across medical, agricultural and ecological fields.
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Affiliation(s)
- Ryan Warr
- grid.5379.80000000121662407Henry Royce Institute, Department of Materials, The University of Manchester, Manchester, M13 9PL UK
| | - Stephan Handschuh
- grid.6583.80000 0000 9686 6466VetCore Facility for Research, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Martin Glösmann
- grid.6583.80000 0000 9686 6466VetCore Facility for Research, University of Veterinary Medicine Vienna, Vienna, Austria
| | - Robert J. Cernik
- grid.5379.80000000121662407Henry Royce Institute, Department of Materials, The University of Manchester, Manchester, M13 9PL UK
| | - Philip J. Withers
- grid.5379.80000000121662407Henry Royce Institute, Department of Materials, The University of Manchester, Manchester, M13 9PL UK
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Jayarathna S, Moktan H, Cho SH. Use of the Fully Spectroscopic Pixelated Cadmium Telluride Detector for Benchtop X-Ray Fluorescence Computed Tomography. IEEE ACCESS : PRACTICAL INNOVATIONS, OPEN SOLUTIONS 2022; 10:105074-105083. [PMID: 36274671 PMCID: PMC9583747 DOI: 10.1109/access.2022.3210590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
In this work, we integrated a commercially-available fully-spectroscopic pixelated cadmium telluride (CdTe) detector system as a two-dimensional (2D) array detector into our existing benchtop cone-beam x-ray fluorescence computed tomography (XFCT) system. After integrating this detector, known as High-Energy X-ray Imaging Technology (HEXITEC), we performed quantitative imaging of gold nanoparticle (GNP) distribution in a small animal-sized phantom using our benchtop XFCT system. Owing to the upgraded detector component within our benchtop XFCT system, we were able to conduct this phantom imaging in an unprecedented manner by volumetric XFCT scans followed by XFCT image reconstruction in 3D. The current results showed that adoption of HEXITEC, in conjunction with a custom-made parallel-hole collimator, drastically reduced the XFCT scan time/dose. Compared with the previous work performed with our original benchtop XFCT system adopting a single crystal CdTe detector, the currently observed reduction was up to a factor of 5, while achieving comparable GNP detection limit under similar experimental conditions. Overall, we demonstrated, for the first time to the best our knowledge, the feasibility of benchtop XFCT imaging of small animal-sized objects containing biologically relevant GNP concentrations (on the order of 0.1 mg Au/cm3 or 100 parts-per-million/ppm), with the scan time (on the order of 1 minute)/x-ray dose (on the order of 10 cGy) that are likely meeting the minimum requirements for routine preclinical imaging applications.
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Affiliation(s)
- Sandun Jayarathna
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hem Moktan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sang Hyun Cho
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
- Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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Materials Separation via the Matrix Method Employing Energy-Discriminating X-ray Detection. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12063198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The majority of lab-based X-ray sources are polychromatic and are not easily tunable, which can make the 3D quantitative analysis of multi-component samples challenging. The lack of effective materials separation when using conventional X-ray tube sources has motivated the development of a number of potential solutions including the application of dual-energy X-ray computed tomography (CT) as well as the use of X-ray filters. Here, we demonstrate the simultaneous decomposition of two low-density materials via inversion of the linear attenuation matrices using data from the energy-discriminating PiXirad detector. A key application for this method is soft-tissue differentiation which is widely used in biological and medical imaging. We assess the effectiveness of this approach using both simulation and experiment noting that none of the materials investigated here incorporate any contrast enhancing agents. By exploiting the energy discriminating properties of the detector, narrow energy bands are created resulting in multiple quasi-monochromatic images being formed using a broadband polychromatic source. Optimization of the key parameters for materials separation is first demonstrated in simulation followed by experimental validation using a phantom test sample in 2D and a small-animal model in 3D.
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Pickford Scienti OLP, Darambara DG. An Overview of X-ray Photon Counting Spectral Imaging (x-CSI) with a Focus on Gold Nanoparticle Quantification in Oncology. J Imaging 2021; 8:4. [PMID: 35049845 PMCID: PMC8778032 DOI: 10.3390/jimaging8010004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 02/07/2023] Open
Abstract
This review article offers an overview of the differences between traditional energy integrating (EI) X-ray imaging and the new technique of X-ray photon counting spectral imaging (x-CSI). The review is motivated by the need to image gold nanoparticles (AuNP) in vivo if they are to be used clinically to deliver a radiotherapy dose-enhancing effect (RDEE). The aim of this work is to familiarise the reader with x-CSI as a technique and to draw attention to how this technique will need to develop to be of clinical use for the described oncological applications. This article covers the conceptual differences between x-CSI and EI approaches, the advantages of x-CSI, constraints on x-CSI system design, and the achievements of x-CSI in AuNP quantification. The results of the review show there are still approximately two orders of magnitude between the AuNP concentrations used in RDEE applications and the demonstrated detection limits of x-CSI. Two approaches to overcome this were suggested: changing AuNP design or changing x-CSI system design. Optimal system parameters for AuNP detection and general spectral performance as determined by simulation studies were different to those used in the current x-CSI systems, indicating potential gains that may be made with this approach.
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Affiliation(s)
- Oliver L. P. Pickford Scienti
- Joint Department of Physics, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London SM2 5NG, UK;
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Moktan H, Panta RK, Cho SH. Bias-voltage dependent operational characteristics of a fully spectroscopic pixelated cadmium telluride detector system within an experimental benchtop x-ray fluorescence imaging setup. Biomed Phys Eng Express 2021; 8. [PMID: 34874017 DOI: 10.1088/2057-1976/ac3d9c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/26/2021] [Indexed: 11/12/2022]
Abstract
Commercially available fully spectroscopic pixelated cadmium telluride (CdTe) detector systems have been adopted lately for benchtop x-ray fluorescence (XRF) imaging/computed tomography (XFCT) of objects containing metal nanoprobes such as gold nanoparticles (GNPs). To date, however, some important characteristics of such detector systems under typical operating conditions of benchtop XRF/XFCT imaging systems are not well known. One important but poorly studied characteristic is the effect of detector bias-voltage on photon counting efficiency, energy resolution, and the resulting material detection limit. In this work, therefore, we investigated these characteristics for a commercial pixelated detector system adopting a 1-mm-thick CdTe sensor (0.25-mm pixel-pitch), known as HEXITEC, incorporated into an experimental benchtop cone-beam XFCT system with parallel-hole detector collimation. The detector system, operated at different bias-voltages, was used to acquire the gold XRF/Compton spectra from 1.0 wt% GNP-loaded phantom irradiated with 125 kVp x-rays filtered by 1.8-mm Tin. At each bias-voltage, the gold XRF signal, and the full-width-at-half-maximum at gold Kα2XRF peak (∼67 keV) provided photon counting efficiency and energy resolution, respectively. Under the current experimental conditions, the detector photon counting efficiency and energy resolution improved with increasing bias-voltage by ∼41 and ∼29% at -300V; ∼54 and ∼35% at -500V, respectively, when compared to those at -100V. Consequently, the GNP detection limit improved by ∼26% at -300V and ∼30% at -500V. Furthermore, the homogeneity of per-pixel energy resolution within the collimated detector area improved by ∼34% at -300V and ∼54% at -500V. These results suggested the gradual improvements in the detector performance with increasing bias-voltage up to -500V. However, at and beyond -550V, there were no discernible improvements in photon counting efficiency and energy resolution. Thus, the bias-voltage range of -500 to -550V was found optimal under the current experimental conditions that are considered typical of benchtop XRF/XFCT imaging tasks.
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Affiliation(s)
- Hem Moktan
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Raj Kumar Panta
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
| | - Sang Hyun Cho
- Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America.,Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States of America
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