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Zhang Y, Fang Y, Abbaraju V, Bhattacharya S, Anker JN, Wang G, Li C. Oxygenation imaging in deep tissue with X-Ray luminescence computed tomography (XLCT). PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2023; 12468:124680I. [PMID: 38957374 PMCID: PMC11218916 DOI: 10.1117/12.2654446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Oxygenation concentration of tissue is an important factor in culturing stem cells and in studying the therapy response of cancer cells. The hypoxia bone marrow is the site to harbor cancer cells. Thus, direct high-resolution measurements of molecular 𝑂2 would provide powerful means of monitoring cultured stem cells and therapied cancer cells. We proposed an imaging approach to measure oxygenation concentration in deep tissues, based on the XLCT, with combined strengths of high chemical sensitivity and high spatial resolution. We have developed different biosensing films for oxygenation measurements and tested these films with X-ray luminescent experiments. We have also performed phantom experiments with multiple targets to validate the XLCT imaging system with measurements at two channels.
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Affiliation(s)
- Yibing Zhang
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Yile Fang
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Vigjna Abbaraju
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | | | - Jeffrey N. Anker
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
- Department of Bioengineering, Center for Optical Materials Science and Engineering Technology (COMSET), and Institute of Environment Toxicology (CU-ENTOX), Clemson University, Clemson, SC 29634, USA
| | - Ge Wang
- Department of Biomedical Engineering, Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
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Lun MC, Ranasinghe M, Arifuzzaman M, Fang Y, Guo Y, Anker JN, Li C. Contrast agents for x-ray luminescence computed tomography. APPLIED OPTICS 2021; 60:6769-6775. [PMID: 34613157 PMCID: PMC10775909 DOI: 10.1364/ao.431080] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Imaging probes are an important consideration for any type of contrast agent-based imaging method. X-ray luminescence imaging (XLI) and x-ray luminescence computed tomography (XLCT) are both contrast agent-based imaging methods that employ x-ray excitable scintillating imaging probes that emit light to be measured for optical imaging. In this work, we compared the performance of several select imaging probes, both commercial and self-synthesized, for application in XLI/XLCT imaging. Commercially available cadmium telluride quantum dots (CdTe QDs) and europium-doped gadolinium oxysulfide (GOS:Eu) microphosphor as well as synthesized NaGdF4 nanophosphors doped with either europium or terbium were compared through their x-ray luminescence emission spectra, luminescence intensity, and also by performing XLCT scans using phantoms embedded with each of the imaging probes. Each imaging probe displayed a unique emission spectrum that was ideal for deep-tissue optical imaging. In terms of luminescence intensity, due to the large particle size, GOS:Eu had the brightest emission, followed by NaGdF4:Tb, NaGdF4:Eu, and finally the CdTe QDs. Lastly, XLCT scans showed that each imaging probe could be reconstructed with good shape and location accuracy.
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Affiliation(s)
- Michael C. Lun
- Department of Bioengineering, University of California, Merced, California 95343, USA
| | | | | | - Yile Fang
- Department of Bioengineering, University of California, Merced, California 95343, USA
| | - Yiping Guo
- Quantitative and Systems Biology Program, University of California, Merced, Merced, California 95343, USA
| | - Jeffrey N. Anker
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, USA
- Center for Optical Materials Science and Engineering, Institute of Environmental Toxicology, Department of Bioengineering, Clemson University, Clemson, South Carolina 29634, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, California 95343, USA
- Quantitative and Systems Biology Program, University of California, Merced, Merced, California 95343, USA
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Lun MC, Cong W, Arifuzzaman M, Ranasinghe M, Bhattacharya S, Anker JN, Wang G, Li C. Focused x-ray luminescence imaging system for small animals based on a rotary gantry. JOURNAL OF BIOMEDICAL OPTICS 2021; 26:JBO-200417R. [PMID: 33738992 PMCID: PMC7970409 DOI: 10.1117/1.jbo.26.3.036004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
SIGNIFICANCE The ability to detect and localize specific molecules through tissue is important for elucidating the molecular basis of disease and treatment. Unfortunately, most current molecular imaging tools in tissue either lack high spatial resolution (e.g., diffuse optical fluorescence tomography or positron emission tomography) or lack molecular sensitivity (e.g., micro-computed tomography, μCT). X-ray luminescence imaging emerged about 10 years ago to address this issue by combining the molecular sensitivity of optical probes with the high spatial resolution of x-ray imaging through tissue. In particular, x-ray luminescence computed tomography (XLCT) has been demonstrated as a powerful technique for the high-resolution imaging of deeply embedded contrast agents in three dimensions (3D) for small-animal imaging. AIM To facilitate the translation of XLCT for small-animal imaging, we have designed and built a small-animal dedicated focused x-ray luminescence tomography (FXLT) scanner with a μCT scanner, synthesized bright and biocompatible nanophosphors as contrast agents, and have developed a deep-learning-based reconstruction algorithm. APPROACH The proposed FXLT imaging system was designed using computer-aided design software and built according to specifications. NaGdF4 nanophosphors doped with europium or terbium were synthesized with a silica shell for increased biocompatibility and functionalized with biotin. A deep-learning-based XLCT image reconstruction was also developed based on the residual neural network as a data synthesis method of projection views from few-view data to enhance the reconstructed image quality. RESULTS We have built the FXLT scanner for small-animal imaging based on a rotational gantry. With all major imaging components mounted, the motor controlling the gantry can be used to rotate the system with a high accuracy. The synthesized nanophosphors displayed distinct x-ray luminescence emission, which enables multi-color imaging, and has successfully been bound to streptavidin-coated substrates. Lastly, numerical simulations using the proposed deep-learning-based reconstruction algorithm has demonstrated a clear enhancement in the reconstructed image quality. CONCLUSIONS The designed FXLT scanner, synthesized nanophosphors, and deep-learning-based reconstruction algorithm show great potential for the high-resolution molecular imaging of small animals.
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Affiliation(s)
- Michael C. Lun
- University of California, Merced, Department of Bioengineering, Merced, California, United States
| | - Wenxiang Cong
- Rensselaer Polytechnic Institute, Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, Troy, New York, United States
| | - Mohammad Arifuzzaman
- Clemson University, Department of Chemistry, Clemson, South Carolina, United States
| | - Meenakshi Ranasinghe
- Clemson University, Department of Chemistry, Clemson, South Carolina, United States
| | - Sriparna Bhattacharya
- Clemson University, Clemson Nanomaterials Institute, Department of Physics and Astronomy, Clemson, South Carolina, United States
| | - Jeffrey N. Anker
- Clemson University, Department of Chemistry, Clemson, South Carolina, United States
- Clemson University, Institute of Environmental Toxicology, Center for Optical Materials Science and Engineering Technology, Department of Bioengineering, Clemson, South Carolina, United States
| | - Ge Wang
- Rensselaer Polytechnic Institute, Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Department of Biomedical Engineering, Troy, New York, United States
| | - Changqing Li
- University of California, Merced, Department of Bioengineering, Merced, California, United States
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Uzair U, Johnson C, Beladi-Behbahani S, Rajamanthrilage AC, Raval YS, Benza D, Ranasinghe M, Schober G, Tzeng TRJ, Anker JN. Conformal Coating of Orthopedic Plates with X-ray Scintillators and pH Indicators for X-ray Excited Luminescence Chemical Imaging through Tissue. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52343-52353. [PMID: 33181017 DOI: 10.1021/acsami.0c13707] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We describe a pH-indicating material that can be directly implanted or coated on orthopedic implant surfaces to provide high-spatial-resolution pH mapping through tissue by X-ray excited luminescence chemical imaging (XELCI). This is especially useful for detecting local pH changes during treatment of implant-associated infections. The material has two layers: an X-ray scintillator layer with Gd2O2S:Eu in epoxy, which emits 620 and 700 nm light when irradiated with X-rays, and a pH indicator dye layer, which absorbs some of the 620 nm light in a pH-dependent fashion. To acquire each pixel in the image, a focused X-ray beam irradiates a small region of scintillators and the ratio of 620 to 700 nm light is acquired through the tissue. Scanning the X-ray beam across the implant surface generates high-spatial-resolution chemical measurements. Two associated challenges are (1) to make robust sensors that can be implanted in tissue to measure local chemical concentrations specifically for metal orthopedic implants and (2) to conformally coat the implant surface with scintillators and pH indicator dyes in order to make measurements over a large area. Previously, we have physically pressed or glued a pH-sensitive hydrogel sensor onto the surface of an implant, but this is impractical for imaging over large irregular device areas such as an orthopedic plate with holes and edges. Herein, we describe a chemically sensitive and biocompatible XELCI sensor material that can conformally coat the implant surface. A two-part commercial-grade epoxy resin was mixed with Gd2O2S:Eu and adhered to the titanium surface. Sugar and salt particles were added to the surface of the epoxy as it cured to create a roughened surface and increase the surface area. On this roughened surface, a secondary layer of diacrylated polyethylene glycol (PEG) hydrogel, containing a pH sensitive dye, was polymerized. This combination of epoxy-PEG layers was found to adhere well to the metal implant unlike other previously tested polymer surfaces, which delaminated when exposed to water or humidity. The focused X-ray beam enabled 0.5 mm spatial resolution through 1 cm-thick tissue. The pH sensor-coated orthopedic plate was imaged with XELCI, through tissue, with different pH levels to acquire a calibration curve. The plates were also imaged through tissue, with a low pH region on one section due to growth of a Staphylococcus aureus biofilm. A pH sensor-coated stainless-steel rod with two distinct pH regions was inserted in a rabbit tibia specimen, and the pH was imaged through both bone and soft tissue. These studies demonstrate the use of pH sensor-coated orthopedic plates and rods for mapping the local pH through tissue during biofilm formation by XELCI.
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Affiliation(s)
- Unaiza Uzair
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Chloe Johnson
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | | | | | - Yash S Raval
- Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, United States
| | - Donald Benza
- Department of Electrical and Computer Engineering, Clemson University, Clemson, South Carolina 29634, United States
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Meenakshi Ranasinghe
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Gretchen Schober
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Tzuen-Rong J Tzeng
- Department of Biological Sciences, Clemson University, Clemson, South Carolina 29634, United States
| | - Jeffrey N Anker
- Departments of Chemistry and Bioengineering, Center for Optical Materials Science and Engineering Technology (COMSET), Clemson University, Clemson, South Carolina 29634, United States
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Zhang Y, Guo Q, Zhang L, Li J, Gao F, Jiang J, Zhou Z. Investigation of a simple coded-aperture based multi-narrow beam x-ray luminescence computed tomography system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:093101. [PMID: 33003801 DOI: 10.1063/5.0008773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 08/12/2020] [Indexed: 06/11/2023]
Abstract
The purpose of this paper is to introduce and study a multi-narrow beam X-ray Luminescence Computed Tomography (XLCT) system based on a simple coded aperture. The proposed XLCT system is studied through simulations of x rays and diffuse light propagation and the implementation of the multi-narrow beam XLCT reconstruction algorithm. The relationship between the reconstructed quality of the XLCT image and the pass-element distribution of the coded aperture mask is investigated. The coded aperture that produces the best image quality metrics for the numerical phantom is selected for the XLCT system. The effects of detection positions and the number of projection angles are also investigated for considering the scanning efficiency and system structural complexity. The results demonstrate that the proposed multi-narrow beam XLCT system is competent in resolving targets with high complexity when comparing with the coded aperture compressed sensing XLCT system based on a complicated mask. It can also offer an enhancement in scanning efficiency in comparison with the conventional multi-narrow beam XLCT system.
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Affiliation(s)
- Yueming Zhang
- School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Qingwei Guo
- Department of Medical Imaging, First Teaching Hospital of Tianjin University of Traditional Chinese, Tianjin 300193, China
| | - Limin Zhang
- School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Jiao Li
- School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Feng Gao
- School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
| | - Jingying Jiang
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, School of Medicine and Engineering, Beihang University, Beijing 100191, China
| | - Zhongxing Zhou
- School of Precision Instrument and Optoelectronics Engineering, Tianjin University, Tianjin 300072, China
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Lun MC, Cong W, Arifuzzaman M, Ranasinghe M, Bhattacharya S, Anker J, Wang G, Li C. X-ray luminescence imaging for small animals. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2020; 11224:112240F. [PMID: 33574637 PMCID: PMC7875188 DOI: 10.1117/12.2544601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
X-ray luminescence imaging emerged for about a decade and combines both the high spatial resolution of x-ray imaging with the high measurement sensitivity of optical imaging, which could result in a great molecular imaging tool for small animals. So far, there are two types of x-ray luminescence computed tomography (XLCT) imaging. One uses a pencil beam x-ray for high spatial resolution at a cost of longer measurement time. The other uses cone beam x-ray to cover the whole mouse to obtain XLCT images at a very short time but with a compromised spatial resolution. Here we review these two methods in this paper and highlight the synthesized nanophosphors by different research groups. We are building a focused x-ray luminescence tomography (FXLT) imaging system, developing a machine-learning based FXLT reconstruction algorithm, and synthesizing nanophosphors with different emission wavelengths. In this paper, we will report our current progress from these three aspects. Briefly, we mount all main components, including the focused x-ray tube, the fiber detector, and the x-ray tube and x-ray detector for a microCT system, on a rotary which is a heavy-duty ring track. A microCT scan will be performed before FXLT scan. For a FXLT scan, we will have four PMTs to measure four fiber detectors at two different wavelengths simultaneously for each linear scan position. We expect the spatial resolution of the FXLT imaging will be around 100 micrometers and a limit of detection of approximately 2 μg/mL (for Gd2O2S:Eu).
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Affiliation(s)
- Michael C Lun
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Wenxiang Cong
- Department of Biomedical Engineering, Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Md. Arifuzzaman
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
| | | | - Sriparna Bhattacharya
- Clemson Nanomaterials Institute, Department of Physics & Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Jeffery Anker
- Department of Chemistry, Clemson University, Clemson, SC 29634, USA
- Department of Bioengineering, Center for Optical Materials Science and Engineering Technology (COMSET), and Institute of Environment Toxicology (CU-ENTOX), Clemson University, Clemson, SC 29634, USA
| | - Ge Wang
- Department of Biomedical Engineering, Biomedical Imaging Center, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
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Lun MC, Li C. High-resolution x-ray luminescence computed tomography. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2020; 11317:113171D. [PMID: 32214600 PMCID: PMC7096071 DOI: 10.1117/12.2544493] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
High-resolution imaging modalities play a critical role for advancing biomedical sciences. Recently, x-ray luminescence computed tomography (XLCT) imaging was introduced as a hybrid molecular imaging modality that combines the high-spatial resolution of x-ray imaging and molecular sensitivity of optical imaging. The narrow x-ray beam based XLCT imaging has been demonstrated to achieve high spatial resolution, even at depth, with great molecular sensitivity. Using a focused x-ray beam as the excitation source, orders of magnitude of increased sensitivity has been verified compared with previous methods with a collimated x-ray beam. In this work, we demonstrate the high-spatial resolution capabilities of our focused x-ray beam based XLCT imaging system by scanning two sets of targets, differing in the target size, embedded inside of two tissue-mimicking cylindrical phantoms. Gd2O2S:Eu3+ targets of 200 µm and 150 µm diameters were created and embedded with the same edge-to-edge distances as their diameters respectively. We scanned and reconstructed a single transverse section and successfully demonstrated that a focused x-ray beam with an average dual-cone size of 125 µm could separate the targets in both phantoms with good shape and location accuracy. We have also improved the current XLCT imaging system to make it feasible for fast three-dimensional XLCT scanning.
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Affiliation(s)
- Michael C. Lun
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
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Zhang Y, Lun MC, Li C, Zhou Z. Method for improving the spatial resolution of narrow x-ray beam-based x-ray luminescence computed tomography imaging. JOURNAL OF BIOMEDICAL OPTICS 2019; 24:1-11. [PMID: 31429215 PMCID: PMC6698719 DOI: 10.1117/1.jbo.24.8.086002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/30/2019] [Indexed: 06/10/2023]
Abstract
X-ray luminescence computed tomography (XLCT) is an emerging hybrid imaging modality which has the potential for achieving both high sensitivity and spatial resolution simultaneously. For the narrow x-ray beam-based XLCT imaging, based on previous work, a spatial resolution of about double the x-ray beam size can be achieved using a translate/rotate scanning scheme, taking step sizes equal to the x-ray beam width. To break the current spatial resolution limit, we propose a scanning strategy achieved by reducing the scanning step size to be smaller than the x-ray beam size. We performed four sets of numerical simulations and a phantom experiment using cylindrical phantoms and have demonstrated that our proposed scanning method can greatly improve the XLCT-reconstructed image quality compared with the traditional scanning approach. In our simulations, by using a fixed x-ray beam size of 0.8 mm, we were able to successfully reconstruct six embedded targets as small as 0.5 mm in diameter and with the same edge-to-edge distances by using a scanning step as small as 0.2 mm which is a 1.6 times improvement in the spatial resolution compared with the traditional approach. Lastly, the phantom experiment further demonstrated the efficacy of our proposed method in improving the XLCT image quality, with all image quality metrics improving as the step size decreased.
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Affiliation(s)
- Yueming Zhang
- Tianjin University, School of Precision Instruments and Optoelectronics Engineering, Tianjin, China
| | - Michael C. Lun
- University of California, Department of Bioengineering, Merced, California, United States
| | - Changqing Li
- University of California, Department of Bioengineering, Merced, California, United States
| | - Zhongxing Zhou
- Tianjin University, School of Precision Instruments and Optoelectronics Engineering, Tianjin, China
- Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments, Tianjin, China
- Tianjin Shareshine Technology Development Co., Ltd., Tianjin, China
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Lun MC, Li C. Background luminescence in x-ray luminescence computed tomography (XLCT) imaging. APPLIED OPTICS 2019; 58:1084-1092. [PMID: 30874158 PMCID: PMC7138411 DOI: 10.1364/ao.58.001084] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
Abstract
X-ray luminescence computed tomography (XLCT) is an emerging hybrid imaging modality. It has been recently reported that materials such as water, tissue, or even air can generate optical photons upon x-ray irradiation, which can increase the noises in measurements of XLCT. In this study, we have investigated the x-ray luminescence from water, air, as well as tissue mimicking phantoms, including one embedded with a 0.01 mg/mL GOS:Eu3+ microphosphor target. We have measured the optical emission spectrum from each sample, including samples of meat and fat, using a spectrograph. Our results indicate that there are plenty of optical photons emitted by x-ray irradiation, and a small nanophosphor concentration, as low as 5.28 μM in a deep background, can provide enough contrast for XLCT imaging.
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Affiliation(s)
- Michael C. Lun
- Department of Bioengineering, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
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Lun MC, Li C. Focused x-ray luminescence computed tomography: experimental studies. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2019; 10871:108710G. [PMID: 32231401 PMCID: PMC7105158 DOI: 10.1117/12.2506927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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.
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Affiliation(s)
- Michael C. Lun
- Department of Bioengineering, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, 5200 North Lake Road, Merced, CA 95343, USA
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Zhang W, Romero IO, Li C. Time domain X-ray luminescence computed tomography: numerical simulations. BIOMEDICAL OPTICS EXPRESS 2019; 10:372-383. [PMID: 30775106 PMCID: PMC6363188 DOI: 10.1364/boe.10.000372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/22/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
X-ray luminescence computed tomography (XLCT) has the potential to image the biodistribution of nanoparticles inside deep tissues. In XLCT, X-ray excitable nanophosphors emit optical photons for tomographic imaging. The lifetime of the nanophosphor signal, rather than its intensity, could be used to extract biological microenvironment information such as oxygenation in deep tumors. In this study, we propose the design, the forward model, and the reconstruction algorithm of a time domain XLCT for lifetime imaging with high spatial resolution. We have investigated the feasibility of the proposed design with numerical simulations. We found that the reconstructed lifetime images are robust to noise levels up to 5% and to unknown optical properties up to 4 times of absorption and scattering coefficients.
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Affiliation(s)
- Wei Zhang
- Institute of Biomedical Engineering, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin 300192, China
| | - Ignacio O. Romero
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
| | - Changqing Li
- Department of Bioengineering, University of California, Merced, Merced, CA 95343, USA
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Zhang W, Lun MC, Nguyen AAT, Li C. X-ray luminescence computed tomography using a focused x-ray beam. JOURNAL OF BIOMEDICAL OPTICS 2017; 22:1-11. [PMID: 29127693 PMCID: PMC5680901 DOI: 10.1117/1.jbo.22.11.116004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 10/12/2017] [Indexed: 05/25/2023]
Abstract
Due to the low x-ray photon utilization efficiency and low measurement sensitivity of the electron multiplying charge coupled device camera setup, the collimator-based narrow beam x-ray luminescence computed tomography (XLCT) usually requires a long measurement time. We, for the first time, report a focused x-ray beam-based XLCT imaging system with measurements by a single optical fiber bundle and a photomultiplier tube (PMT). An x-ray tube with a polycapillary lens was used to generate a focused x-ray beam whose x-ray photon density is 1200 times larger than a collimated x-ray beam. An optical fiber bundle was employed to collect and deliver the emitted photons on the phantom surface to the PMT. The total measurement time was reduced to 12.5 min. For numerical simulations of both single and six fiber bundle cases, we were able to reconstruct six targets successfully. For the phantom experiment, two targets with an edge-to-edge distance of 0.4 mm and a center-to-center distance of 0.8 mm were successfully reconstructed by the measurement setup with a single fiber bundle and a PMT.
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Affiliation(s)
- Wei Zhang
- University of California, Merced, School of Engineering, Merced, California, United States
| | - Michael C. Lun
- University of California, Merced, School of Engineering, Merced, California, United States
| | - Alex Anh-Tu Nguyen
- University of California, Merced, School of Engineering, Merced, California, United States
| | - Changqing Li
- University of California, Merced, School of Engineering, Merced, California, United States
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