1
|
Cosmi V, Wang B, Goorden MC, Beekman FJ. NaI gamma camera performance for high energies: Effects of crystal thickness, photomultiplier tube geometry and light guide thickness. Med Phys 2024. [PMID: 38569052 DOI: 10.1002/mp.17043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 12/18/2023] [Accepted: 03/12/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND Gamma camera imaging, including single photon emission computed tomography (SPECT), is crucial for research, diagnostics, and radionuclide therapy. Gamma cameras are predominantly based on arrays of photon multipliers tubes (PMTs) that read out NaI(Tl) scintillation crystals. In this way, standard gamma cameras can localize ɣ-rays with energies typically ranging from 30 to 360 keV. In the last decade, there has been an increasing interest towards gamma imaging outside this conventional clinical energy range, for example, for theragnostic applications and preclinical multi-isotope positron emission tomography (PET) and PET-SPECT. However, standard gamma cameras are typically equipped with 9.5 mm thick NaI(Tl) crystals which can result in limited sensitivity for these higher energies. PURPOSE Here we investigate to what extent thicker scintillators can improve the photopeak sensitivity for higher energy isotopes while attempting to maintain spatial resolution. METHODS Using Monte Carlo simulations, we analyzed multiple PMT-based configurations of gamma detectors with monolithic NaI (Tl) crystals of 20 and 40 mm thickness. Optimized light guide thickness together with 2-inch round, 3-inch round, 60 × 60 mm2 square, and 76 × 76 mm2 square PMTs were tested. For each setup, we assessed photopeak sensitivity, energy resolution, spatial, and depth-of-interaction (DoI) resolution for conventional (140 keV) and high (511 keV) energy ɣ using a maximum-likelihood algorithm. These metrics were compared to those of a "standard" 9.5 mm-thick crystal detector with 3-inch round PMTs. RESULTS Estimated photopeak sensitivities for 511 keV were 27% and 53% for 20 and 40 mm thick scintillators, which is respectively, 2.2 and 4.4 times higher than for 9.5 mm thickness. In most cases, energy resolution benefits from using square PMTs instead of round ones, regardless of their size. Lateral and DoI spatial resolution are best for smaller PMTs (2-inch round and 60 × 60 mm2 square) which outperform the more cost-effective larger PMT setups (3-inch round and 76 × 76 mm2 square), while PMT layout and shape have negligible (< 10%) effect on resolution. Best spatial resolution was obtained with 60 × 60 mm2 PMTs; for 140 keV, lateral resolution was 3.5 mm irrespective of scintillator thickness, improving to 2.8 and 2.9 mm for 511 keV with 20 and 40 mm thick crystals, respectively. Using the 3-inch round PMTs, lateral resolutions of 4.5 and 3.9 mm for 140 keV and of 3.5 and 3.7 mm for 511 keV were obtained with 20 and 40 mm thick crystals respectively, indicating a moderate performance degradation compared to the 3.5 and 2.9 mm resolution obtained by the standard detector for 140 and 511 keV. Additionally, DoI resolution for 511 keV was 7.0 and 5.6 mm with 20 and 40 mm crystals using 60 × 60 mm2 square PMTs, while with 3-inch round PMTs 12.1 and 5.9 mm were obtained. CONCLUSION Depending on PMT size and shape, the use of thicker scintillator crystals can substantially improve detector sensitivity at high gamma energies, while spatial resolution is slightly improved or mildly degraded compared to standard crystals.
Collapse
Affiliation(s)
- Valerio Cosmi
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Beien Wang
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Marlies C Goorden
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Freek J Beekman
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
- Free Bee International, Gouda, The Netherlands
| |
Collapse
|
2
|
Nguyen MP, Arif M, Oostenrijk B, Goorden MC, Beekman FJ. A scanning focus nuclear microscope with multi-pinhole collimation. Phys Med Biol 2023; 68. [PMID: 36848684 DOI: 10.1088/1361-6560/acbf9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 02/27/2023] [Indexed: 03/01/2023]
Abstract
Microscopic nuclear imaging down to spatial resolutions of a few hundred microns can already be achieved using low-energy gamma emitters (e.g.125I, ∼30 keV) and a basic single micro-pinhole gamma camera. This has been applied toin vivomouse thyroid imaging, for example. For clinically used radionuclides such as99mTc, this approach fails due to penetration of the higher-energy gamma photons through the pinhole edges. To overcome these resolution degradation effects, we propose a new imaging approach: scanning focus nuclear microscopy (SFNM). We assess SFNM using Monte Carlo simulations for clinically used isotopes. SFNM is based on the use of a 2D scanning stage with a focused multi-pinhole collimator containing 42 pinholes with narrow pinhole aperture opening angles to reduce photon penetration. All projections of different positions are used to iteratively reconstruct a three-dimensional image from which synthetic planar images are generated. SFNM imaging was tested using a digital Derenzo resolution phantom and a mouse ankle joint phantom containing99mTc (140 keV). The planar images were compared with those obtained using a single-pinhole collimator, either with matched pinhole diameter or with matched sensitivity. The simulation results showed an achievable99mTc image resolution of 0.04 mm and detailed99mTc bone images of a mouse ankle with SFNM. SFNM has strong advantages over single-pinhole imaging in terms of spatial resolution.
Collapse
Affiliation(s)
- Minh Phuong Nguyen
- MILabs BV, Houten, The Netherlands
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
- Delft University of Technology, Mekelweg 5, 2628 CD Delft, The Netherlands
| | - Muhammad Arif
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
| | | | - Marlies C Goorden
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Freek J Beekman
- MILabs BV, Houten, The Netherlands
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
3
|
Lilius TO, Mortensen KN, Deville C, Lohela TJ, Stæger FF, Sigurdsson B, Fiordaliso EM, Rosenholm M, Kamphuis C, Beekman FJ, Jensen AI, Nedergaard M. Glymphatic-assisted perivascular brain delivery of intrathecal small gold nanoparticles. J Control Release 2023; 355:135-148. [PMID: 36731802 DOI: 10.1016/j.jconrel.2023.01.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 11/05/2022] [Accepted: 01/18/2023] [Indexed: 02/04/2023]
Abstract
Nanoparticles are ultrafine particulate matter having considerable potential for treatment of central nervous system (CNS) disorders. Despite their tiny size, the blood-brain barrier (BBB) restricts their access to the CNS. Their direct cerebrospinal fluid (CSF) administration bypasses the BBB endothelium, but still fails to give adequate brain uptake. We present a novel approach for efficient CNS delivery of 111In-radiolabelled gold nanoparticles (AuNPs; 10-15 nm) via intra-cisterna magna administration, with tracking by SPECT imaging. To accelerate CSF brain influx, we administered AuNPs intracisternally in conjunction with systemic hypertonic saline, which dramatically increased the parenchymal AuNP uptake, especially in deep brain regions. AuNPs entered the CNS along periarterial spaces as visualized by MRI of gadolinium-labelled AuNPs and were cleared from brain within 24 h and excreted through the kidneys. Thus, the glymphatic-assisted perivascular network augment by systemic hypertonic saline is a pathway for highly efficient brain-wide distribution of small AuNPs.
Collapse
Affiliation(s)
- Tuomas O Lilius
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Emergency Medicine and Services, University of Helsinki and Helsinki University Hospital, Finland
| | - Kristian Nygaard Mortensen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claire Deville
- The Hevesy Laboratory, Department of Health Technology, Technical University of Denmark, Roskilde, Denmark
| | - Terhi J Lohela
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Anaesthesiology, Intensive Care Medicine, and Pain Medicine, University of Helsinki and Helsinki University Hospital, Finland
| | - Frederik Filip Stæger
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elisabetta M Fiordaliso
- DTU Nanolab - National Center for Nano Fabrication and Characterization, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Marko Rosenholm
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Chris Kamphuis
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands; MILabs B.V., Utrecht, the Netherlands
| | - Freek J Beekman
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands; MILabs B.V., Utrecht, the Netherlands; Department of Radiation Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Andreas I Jensen
- The Hevesy Laboratory, Department of Health Technology, Technical University of Denmark, Roskilde, Denmark.
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA.
| |
Collapse
|
4
|
van Dijk B, Hooning van Duyvenbode JFF, de Vor L, Nurmohamed FRHA, Lam MGEH, Poot AJ, Ramakers RM, Koustoulidou S, Beekman FJ, van Strijp J, Rooijakkers SHM, Dadachova E, Vogely HC, Weinans H, van der Wal BCH. Evaluating the Targeting of a Staphylococcus-aureus-Infected Implant with a Radiolabeled Antibody In Vivo. Int J Mol Sci 2023; 24:ijms24054374. [PMID: 36901805 PMCID: PMC10002501 DOI: 10.3390/ijms24054374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/06/2023] [Accepted: 02/16/2023] [Indexed: 02/25/2023] Open
Abstract
Implant infections caused by Staphylococcus aureus are difficult to treat due to biofilm formation, which complicates surgical and antibiotic treatment. We introduce an alternative approach using monoclonal antibodies (mAbs) targeting S. aureus and provide evidence of the specificity and biodistribution of S.-aureus-targeting antibodies in a mouse implant infection model. The monoclonal antibody 4497-IgG1 targeting wall teichoic acid in S. aureus was labeled with indium-111 using CHX-A"-DTPA as a chelator. Single Photon Emission Computed Tomography/computed tomographyscans were performed at 24, 72 and 120 h after administration of the 111In-4497 mAb in Balb/cAnNCrl mice with a subcutaneous implant that was pre-colonized with S. aureus biofilm. The biodistribution of this labelled antibody over various organs was visualized and quantified using SPECT/CT imaging, and was compared to the uptake at the target tissue with the implanted infection. Uptake of the 111In-4497 mAbs at the infected implant gradually increased from 8.34 %ID/cm3 at 24 h to 9.22 %ID/cm3 at 120 h. Uptake at the heart/blood pool decreased over time from 11.60 to 7.58 %ID/cm3, whereas the uptake in the other organs decreased from 7.26 to less than 4.66 %ID/cm3 at 120 h. The effective half-life of 111In-4497 mAbs was determined to be 59 h. In conclusion, 111In-4497 mAbs were found to specifically detect S. aureus and its biofilm with excellent and prolonged accumulation at the site of the colonized implant. Therefore, it has the potential to serve as a drug delivery system for the diagnostic and bactericidal treatment of biofilm.
Collapse
Affiliation(s)
- Bruce van Dijk
- Department of Orthopedics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-88-75-569-71
| | | | - Lisanne de Vor
- Department of Medical Microbiology, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands
| | | | - Marnix G. E. H. Lam
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Alex J. Poot
- Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Ruud M. Ramakers
- MILabs B.V., 3584 CX Utrecht, The Netherlands
- Department of Radiation Science and Technology, Delft University of Technology, 2628 CD Delft, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center, 3584 CX Utrecht, The Netherlands
| | - Sofia Koustoulidou
- MILabs B.V., 3584 CX Utrecht, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center, 3584 CX Utrecht, The Netherlands
| | - Freek J. Beekman
- MILabs B.V., 3584 CX Utrecht, The Netherlands
- Department of Radiation Science and Technology, Delft University of Technology, 2628 CD Delft, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center, 3584 CX Utrecht, The Netherlands
| | - Jos van Strijp
- Department of Medical Microbiology, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands
| | - Suzan H. M. Rooijakkers
- Department of Medical Microbiology, University Medical Centre Utrecht, 3584 CX Utrecht, The Netherlands
| | - Ekaterina Dadachova
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada
| | - H. Charles Vogely
- Department of Orthopedics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Harrie Weinans
- Department of Orthopedics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
- Department of BioMechanical Engineering, Delft University of Technology, 2628 CD Delft, The Netherlands
| | - Bart C. H. van der Wal
- Department of Orthopedics, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| |
Collapse
|
5
|
Van der Heiden K, Barrett HE, Meester EJ, van Gaalen K, Krenning BJ, Beekman FJ, de Blois E, de Swart J, Verhagen HJM, van der Lugt A, Norenberg JP, de Jong M, Bernsen MR, Gijsen FJH. SPECT/CT imaging of inflammation and calcification in human carotid atherosclerosis to identify the plaque at risk of rupture. J Nucl Cardiol 2022; 29:2487-2496. [PMID: 34318395 PMCID: PMC9553768 DOI: 10.1007/s12350-021-02745-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/28/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND Calcification and inflammation are atherosclerotic plaque compositional biomarkers that have both been linked to stroke risk. The aim of this study was to evaluate their co-existing prevalence in human carotid plaques with respect to plaque phenotype to determine the value of hybrid imaging for the detection of these biomarkers. METHODS Human carotid plaque segments, obtained from endarterectomy, were incubated in [111In]In-DOTA-butylamino-NorBIRT ([111In]In-Danbirt), targeting Leukocyte Function-associated Antigen-1 (LFA-1) on leukocytes. By performing SPECT/CT, both inflammation from DANBIRT uptake and calcification from CT imaging were assessed. Plaque phenotype was classified using histology. RESULTS On a total plaque level, comparable levels of calcification volume existed with different degrees of inflammation and vice versa. On a segment level, an inverse relationship between calcification volume and inflammation was evident in highly calcified segments, which classify as fibrocalcific, stable plaque segments. In contrast, segments with little or no calcification presented with a moderate to high degree of inflammation, often coinciding with the more dangerous fibrous cap atheroma phenotype. CONCLUSION Calcification imaging alone can only accurately identify highly calcified, stable, fibrocalcific plaques. To identify high-risk plaques, with little or no calcification, hybrid imaging of calcification and inflammation could provide diagnostic benefit.
Collapse
Affiliation(s)
- K Van der Heiden
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands.
| | - H E Barrett
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - E J Meester
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - K van Gaalen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands
| | - B J Krenning
- Department of Cardiology, Erasmus MC, Rotterdam, The Netherlands
| | - F J Beekman
- MiLabs, B.V, Utrecht, The Netherlands
- Section Biomedical Imaging, Department Radiation Science & Technology, Delft University of Technology, Delft, The Netherlands
- Department of Translational Neuroscience, Brain Centre Rudolf Magnus, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - E de Blois
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - J de Swart
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - H J M Verhagen
- Department of Vascular Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - A van der Lugt
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - J P Norenberg
- Radiopharmaceutical Sciences, University of New Mexico, Albuquerque, NM, USA
| | - M de Jong
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
| | - M R Bernsen
- Department of Radiology & Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Applied Molecular Imaging Erasmus Core Facility, Erasmus MC Rotterdam, Rotterdam, The Netherlands
| | - F J H Gijsen
- Department of Biomedical Engineering, Thorax Center, Erasmus MC, Rotterdam, The Netherlands
| |
Collapse
|
6
|
Liu H, de Kruijff RM, Laan AC, Beekman FJ, van den Heuvel E, Ramakers RM, Eelkema R, Denkova AG. Efficient Radiolabeling of Block Copolymer Micelles Through Radiometal Salt Precipitation for Theranostic Applications. Advanced Therapeutics 2022. [DOI: 10.1002/adtp.202200077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Huanhuan Liu
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
| | - Robin M. de Kruijff
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
| | - Adrianus C. Laan
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
| | - Freek J. Beekman
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
- MILabs B.V. Heidelberglaan 100 Utrecht 3584 CX The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus University Medical Center Utrecht Lundlaan Utrecht 3584 The Netherlands
| | - Eline van den Heuvel
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
| | - Ruud M. Ramakers
- Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 Delft 2629 JB The Netherlands
- MILabs B.V. Heidelberglaan 100 Utrecht 3584 CX The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus University Medical Center Utrecht Lundlaan Utrecht 3584 The Netherlands
| | - Rienk Eelkema
- Department of Chemical Engineering Delft University of Technology Delft 2629 HZ The Netherlands
| | - Antonia G. Denkova
- Department of Radiation Science and Technology Delft University of Technology Delft 2629 JB The Netherlands
| |
Collapse
|
7
|
de Vor L, van Dijk B, van Kessel K, Kavanaugh JS, de Haas C, Aerts PC, Viveen MC, Boel EC, Fluit AC, Kwiecinski JM, Krijger GC, Ramakers RM, Beekman FJ, Dadachova E, Lam MGEH, Vogely HC, van der Wal BCH, van Strijp JAG, Horswill AR, Weinans H, Rooijakkers SHM. Human monoclonal antibodies against Staphylococcus aureus surface antigens recognize in vitro and in vivo biofilm. eLife 2022; 11:e67301. [PMID: 34989676 PMCID: PMC8751199 DOI: 10.7554/elife.67301] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 12/06/2021] [Indexed: 12/22/2022] Open
Abstract
Implant-associated Staphylococcus aureus infections are difficult to treat because of biofilm formation. Bacteria in a biofilm are often insensitive to antibiotics and host immunity. Monoclonal antibodies (mAbs) could provide an alternative approach to improve the diagnosis and potential treatment of biofilm-related infections. Here, we show that mAbs targeting common surface components of S. aureus can recognize clinically relevant biofilm types. The mAbs were also shown to bind a collection of clinical isolates derived from different biofilm-associated infections (endocarditis, prosthetic joint, catheter). We identify two groups of antibodies: one group that uniquely binds S. aureus in biofilm state and one that recognizes S. aureus in both biofilm and planktonic state. Furthermore, we show that a mAb recognizing wall teichoic acid (clone 4497) specifically localizes to a subcutaneously implanted pre-colonized catheter in mice. In conclusion, we demonstrate the capacity of several human mAbs to detect S. aureus biofilms in vitro and in vivo.
Collapse
Affiliation(s)
- Lisanne de Vor
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Bruce van Dijk
- Department of Orthopedics, University Medical Centre UtrechtUtrechtNetherlands
| | - Kok van Kessel
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Jeffrey S Kavanaugh
- Department of Immunology and Microbiology, University of Colorado School of MedicineAuroraUnited States
| | - Carla de Haas
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Piet C Aerts
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Marco C Viveen
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Edwin C Boel
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Ad C Fluit
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Jakub M Kwiecinski
- Department of Immunology and Microbiology, University of Colorado School of MedicineAuroraUnited States
| | - Gerard C Krijger
- Department of Radiology and Nuclear Medicine, University Medical Centre UtrechtUtrechtNetherlands
| | - Ruud M Ramakers
- MILabs B.VUtrechtNetherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical CenterUtrechtNetherlands
- Department of Radiation Science and Technology, Delft University of TechnologyDelftNetherlands
| | - Freek J Beekman
- MILabs B.VUtrechtNetherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical CenterUtrechtNetherlands
- Department of Radiation Science and Technology, Delft University of TechnologyDelftNetherlands
| | - Ekaterina Dadachova
- College of Pharmacy and Nutrition, University of SaskatchewanSaskatoonCanada
| | - Marnix GEH Lam
- Department of Radiology and Nuclear Medicine, University Medical Centre UtrechtUtrechtNetherlands
| | - H Charles Vogely
- Department of Orthopedics, University Medical Centre UtrechtUtrechtNetherlands
| | - Bart CH van der Wal
- Department of Orthopedics, University Medical Centre UtrechtUtrechtNetherlands
| | - Jos AG van Strijp
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| | - Alexander R Horswill
- Department of Immunology and Microbiology, University of Colorado School of MedicineAuroraUnited States
- Department of Veterans Affairs, Eastern Colorado Health Care SystemDenverUnited States
| | - Harrie Weinans
- Department of Orthopedics, University Medical Centre UtrechtUtrechtNetherlands
- Department of Biomechanical engineering, TU DelftDelftNetherlands
| | - Suzan HM Rooijakkers
- Department of Medical Microbiology, University Medical Centre UtrechtUtrechtNetherlands
| |
Collapse
|
8
|
Chen Y, Goorden MC, Beekman FJ. Convolutional neural network based attenuation correction for 123I-FP-CIT SPECT with focused striatum imaging. Phys Med Biol 2021; 66. [PMID: 34492646 DOI: 10.1088/1361-6560/ac2470] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/07/2021] [Indexed: 11/12/2022]
Abstract
SPECT imaging with123I-FP-CIT is used for diagnosis of neurodegenerative disorders like Parkinson's disease. Attenuation correction (AC) can be useful for quantitative analysis of123I-FP-CIT SPECT. Ideally, AC would be performed based on attenuation maps (μ-maps) derived from perfectly registered CT scans. Suchμ-maps, however, are most times not available and possible errors in image registration can induce quantitative inaccuracies in AC corrected SPECT images. Earlier, we showed that a convolutional neural network (CNN) based approach allows to estimate SPECT-alignedμ-maps for full brain perfusion imaging using only emission data. Here we investigate the feasibility of similar CNN methods for axially focused123I-FP-CIT scans. We tested our approach on a high-resolution multi-pinhole prototype clinical SPECT system in a Monte Carlo simulation study. Three CNNs that estimateμ-maps in a voxel-wise, patch-wise and image-wise manner were investigated. As the added value of AC on clinical123I-FP-CIT scans is still debatable, the impact of AC was also reported to check in which cases CNN based AC could be beneficial. AC using the ground truthμ-maps (GT-AC) and CNN estimatedμ-maps (CNN-AC) were compared with the case when no AC was done (No-AC). Results show that the effect of using GT-AC versus CNN-AC or No-AC on striatal shape and symmetry is minimal. Specific binding ratios (SBRs) from localized regions show a deviation from GT-AC≤2.5% for all three CNN-ACs while No-AC systematically underestimates SBRs by 13.1%. A strong correlation (r≥0.99) was obtained between GT-AC based SBRs and SBRs from CNN-ACs and No-AC. Absolute quantification (in kBq ml-1) shows a deviation from GT-AC within 2.2% for all three CNN-ACs and of 71.7% for No-AC. To conclude, all three CNNs show comparable performance in accurateμ-map estimation and123I-FP-CIT quantification. CNN-estimatedμ-map can be a promising substitute for CT-basedμ-map.
Collapse
Affiliation(s)
- Yuan Chen
- Section Biomedical Imaging, Department of Radiation, Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Marlies C Goorden
- Section Biomedical Imaging, Department of Radiation, Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Freek J Beekman
- Section Biomedical Imaging, Department of Radiation, Science and Technology, Delft University of Technology, Delft, The Netherlands.,MILabs B.V., Utrecht, The Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| |
Collapse
|
9
|
Nguyen MP, Goorden MC, Ramakers RM, Beekman FJ. Efficient Monte-Carlo based system modelling for image reconstruction in preclinical pinhole SPECT. Phys Med Biol 2021; 66. [PMID: 34049291 DOI: 10.1088/1361-6560/ac0682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/28/2021] [Indexed: 11/11/2022]
Abstract
The use of multi-pinhole collimation has enabled ultra-high-resolution imaging of SPECT and PET tracers in small animals. Key for obtaining high-quality images is the use of statistical iterative image reconstruction with accurate energy-dependent photon transport modelling through collimator and detector. This can be incorporated in a system matrix that contains the probabilities that a photon emitted from a certain voxel is detected at a specific detector pixel. Here we introduce a fast Monte-Carlo based (FMC-based) matrix generation method for pinhole imaging that is easy to apply to various radionuclides. The method is based on accelerated point source simulations combined with model-based interpolation to straightforwardly change or combine photon energies of the radionuclide of interest. The proposed method was evaluated for a VECTor PET-SPECT system with (i) a HE-UHR-M collimator and (ii) an EXIRAD-3D 3D autoradiography collimator. Both experimental scans with99mTc,111In, and123I, and simulated scans with67Ga and90Y were performed for evaluation. FMC was compared with two currently used approaches, one based on a set of point source measurements with99mTc (dubbed traditional method), and the other based on an energy-dependent ray-tracing simulation (ray-tracing method). The reconstruction results show better image quality when using FMC-based matrices than when applying the traditional or ray-tracing matrices in various cases. FMC-based matrices generalise better than the traditional matrices when imaging radionuclides with energies deviating too much from the energy used in the calibration and are computationally more efficient for very-high-resolution imaging than the ray-tracing matrices. In addition, FMC has the advantage of easily combining energies in a single matrix which is relevant when imaging radionuclides with multiple photopeak energies (e.g.67Ga and111In) or with a continuous energy spectrum (e.g.90Y). To conclude, FMC is an efficient, accurate, and versatile tool for creating system matrices for ultra-high-resolution pinhole SPECT.
Collapse
Affiliation(s)
- Minh Phuong Nguyen
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Marlies C Goorden
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Ruud M Ramakers
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands.,MILabs B.V., Utrecht, The Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Freek J Beekman
- Section Biomedical Imaging, Delft University of Technology, Delft, The Netherlands.,MILabs B.V., Utrecht, The Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| |
Collapse
|
10
|
Willemsen K, Ketel MHM, Zijlstra F, Florkow MC, Kuiper RJA, van der Wal BCH, Weinans H, Pouran B, Beekman FJ, Seevinck PR, Sakkers RJB. 3D-printed saw guides for lower arm osteotomy, a comparison between a synthetic CT and CT-based workflow. 3D Print Med 2021; 7:13. [PMID: 33914209 PMCID: PMC8082893 DOI: 10.1186/s41205-021-00103-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/14/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Three-dimensional (3D)-printed saw guides are frequently used to optimize osteotomy results and are usually designed based on computed tomography (CT), despite the radiation burden, as radiation-less alternatives like magnetic resonance imaging (MRI) have inferior bone visualization capabilities. This study investigated the usability of MR-based synthetic-CT (sCT), a novel radiation-less bone visualization technique for 3D planning and design of patient-specific saw guides. METHODS Eight human cadaveric lower arms (mean age: 78y) received MRI and CT scans as well as high-resolution micro-CT. From the MRI scans, sCT were generated using a conditional generative adversarial network. Digital 3D bone surface models based on the sCT and general CT were compared to the surface model from the micro-CT that was used as ground truth for image resolution. From both the sCT and CT digital bone models saw guides were designed and 3D-printed in nylon for one proximal and one distal bone position for each radius and ulna. Six blinded observers placed these saw guides as accurately as possible on dissected bones. The position of each guide was assessed by optical 3D-scanning of each bone with positioned saw guide and compared to the preplanning. Eight placement errors were evaluated: three translational errors (along each axis), three rotational errors (around each axis), a total translation (∆T) and a total rotation error (∆R). RESULTS Surface models derived from micro-CT were on average smaller than sCT and CT-based models with average differences of 0.27 ± 0.30 mm for sCT and 0.24 ± 0.12 mm for CT. No statistically significant positioning differences on the bones were found between sCT- and CT-based saw guides for any axis specific translational or rotational errors nor between the ∆T (p = .284) and ∆R (p = .216). On Bland-Altman plots, the ∆T and ∆R limits of agreement (LoA) were within the inter-observer variability LoA. CONCLUSIONS This research showed a similar error for sCT and CT digital surface models when comparing to ground truth micro-CT models. Additionally, the saw guide study showed equivalent CT- and sCT-based saw guide placement errors. Therefore, MRI-based synthetic CT is a promising radiation-less alternative to CT for the creation of patient-specific osteotomy surgical saw guides.
Collapse
Affiliation(s)
- Koen Willemsen
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. .,3D Lab, Division of Surgical Specialties, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Mirte H M Ketel
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Frank Zijlstra
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mateusz C Florkow
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ruurd J A Kuiper
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Bart C H van der Wal
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| | - Harrie Weinans
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.,3D Lab, Division of Surgical Specialties, University Medical Center Utrecht, Utrecht, The Netherlands.,Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| | - Behdad Pouran
- MILabs B.V, Houten, The Netherlands.,Department of Translational Neuroscience, Brain Centre Rudolf Magnus, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - Freek J Beekman
- MILabs B.V, Houten, The Netherlands.,Department of Translational Neuroscience, Brain Centre Rudolf Magnus, University Medical Centre Utrecht, Utrecht, The Netherlands.,Department Radiation Science & Technology, Delft University of Technology, Delft, The Netherlands
| | - Peter R Seevinck
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ralph J B Sakkers
- Department of Orthopedics, University Medical Center Utrecht, HP:05-228, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
| |
Collapse
|
11
|
Chen Y, Goorden MC, Beekman FJ. Automatic attenuation map estimation from SPECT data only for brain perfusion scans using convolutional neural networks. Phys Med Biol 2021; 66:065006. [PMID: 33571975 DOI: 10.1088/1361-6560/abe557] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In clinical brain SPECT, correction for photon attenuation in the patient is essential to obtain images which provide quantitative information on the regional activity concentration per unit volume (kBq.[Formula: see text]). This correction generally requires an attenuation map ([Formula: see text] map) denoting the attenuation coefficient at each voxel which is often derived from a CT or MRI scan. However, such an additional scan is not always available and the method may suffer from registration errors. Therefore, we propose a SPECT-only-based strategy for [Formula: see text] map estimation that we apply to a stationary multi-pinhole clinical SPECT system (G-SPECT-I) for 99mTc-HMPAO brain perfusion imaging. The method is based on the use of a convolutional neural network (CNN) and was validated with Monte Carlo simulated scans. Data acquired in list mode was used to employ the energy information of both primary and scattered photons to obtain information about the tissue attenuation as much as possible. Multiple SPECT reconstructions were performed from different energy windows over a large energy range. Locally extracted 4D SPECT patches (three spatial plus one energy dimension) were used as input for the CNN which was trained to predict the attenuation coefficient of the corresponding central voxel of the patch. Results show that Attenuation Correction using the Ground Truth [Formula: see text] maps (GT-AC) or using the CNN estimated [Formula: see text] maps (CNN-AC) achieve comparable accuracy. This was confirmed by a visual assessment as well as a quantitative comparison; the mean deviation from the GT-AC when using the CNN-AC is within 1.8% for the standardized uptake values in all brain regions. Therefore, our results indicate that a CNN-based method can be an automatic and accurate tool for SPECT attenuation correction that is independent of attenuation data from other imaging modalities or human interpretations about head contours.
Collapse
Affiliation(s)
- Yuan Chen
- Section Biomedical Imaging, Department of Radiation, Science and Technology, Delft University of Technology, Delft, The Netherlands
| | | | | |
Collapse
|
12
|
Abstract
Despite improvements in small animal PET instruments, many tracers cannot be imaged at sufficiently high resolutions due to positron range, while multi-tracer PET is hampered by the fact that all annihilation photons have equal energies. Here we realize multi-isotope and sub-mm resolution PET of isotopes with several mm positron range by utilizing prompt gamma photons that are commonly neglected. A PET-SPECT-CT scanner (VECTor/CT, MILabs, The Netherlands) equipped with a high-energy cluster-pinhole collimator was used to image 124I and a mix of 124I and 18F in phantoms and mice. In addition to positrons (mean range 3.4 mm) 124I emits large amounts of 603 keV prompt gammas that-aided by excellent energy discrimination of NaI-were selected to reconstruct 124I images that are unaffected by positron range. Photons detected in the 511 keV window were used to reconstruct 18F images. Images were reconstructed iteratively using an energy dependent matrix for each isotope. Correction of 18F images for contamination with 124I annihilation photons was performed by Monte Carlo based range modelling and scaling of the 124I prompt gamma image before subtracting it from the 18F image. Additionally, prompt gamma imaging was tested for 89Zr that emits very high-energy prompts (909 keV). In Derenzo resolution phantoms 0.75 mm rods were clearly discernable for 124I, 89Zr and for simultaneously acquired 124I and 18F imaging. Image quantification in phantoms with reservoirs filled with both 124I and 18F showed excellent separation of isotopes and high quantitative accuracy. Mouse imaging showed uptake of 124I in tiny thyroid parts and simultaneously injected 18F-NaF in bone structures. The ability to obtain PET images at sub-mm resolution both for isotopes with several mm positron range and for multi-isotope PET adds to many other unique capabilities of VECTor's clustered pinhole imaging, including simultaneous sub-mm PET-SPECT and theranostic high energy SPECT.
Collapse
Affiliation(s)
- F J Beekman
- Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands. MILabs B.V., Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
13
|
Aime S, Amirshaghaghi A, Angel PM, Ardenkjaer-Larsen JH, Atreya R, Awe S, Badea CT, Beekman FJ, Biade S, Borden MA, Brunsing RL, Chandrasekharan P, Chang JB, Chen F, Chen JW, Chen X, Cheng Z, Cheng Z, Cherin E, Clinthorne NH, Cohen J, Colson C, Conolly S, Contag CH, Cutler CS, Dayton PA, Devoogdt N, Dina O, Drake RR, Dubsky S, Ducongé F, Fellows BD, Foster FS, Francis KP, Fung BK, Gambhir SS, Gao R, Giovenzana GB, Goodwill P, Goorden MC, Gorpas D, Grimm J, Groll AN, Hargus S, Harmsen S, He S, Hensley D, Hutton BF, Huynh Q, Iagaru A, Josephson L, Jurisson SS, Keselman P, Kircher MF, Kokate T, Konkle J, Korsen JA, Krasniqi A, Laniyonu A, Levin CS, Lewis MR, Lewis JS, Liu G, Liu Y, Looger LL, Lu K, Lu Y, Lucignani G, Lyons SK, Maina T, Martelli C, Matheson AM, Mempel TR, Meng LJ, Moradi F, Nagle VL, Neurath MF, Nicolson F, Nie L, Ntziachristos V, Orendorff R, Ottobrini L, Ouyang Y, Paez Segala MG, Parraga G, Perez-Liva M, Pratt EC, Rao J, Rath T, Rodriguez E, Rosenthal EL, Ross BD, Saayujya C, Saritas EU, Scott DA, Sheth VR, Slagle C, Tamura R, Tavitian B, Tay ZW, Terreno E, Thakur M, Thompson C, Tian J, Travagin F, Tsourkas A, Tully KM, Usmani SM, VanBrocklin HF, van Keulen S, van Zijl PC, Walmer RW, Wang C, Wang J, Wang LV, Xavier C, Yao J, Yu EY, Zheng X, Zheng B, Zhou XY. Contributors. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.01002-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
|
14
|
Nguyen MP, Goorden MC, Beekman FJ. EXIRAD-HE: multi-pinhole high-resolution ex vivo imaging of high-energy isotopes. ACTA ACUST UNITED AC 2020; 65:225029. [DOI: 10.1088/1361-6560/abbb77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
15
|
Wang B, van Roosmalen J, Kreuger R, Huizenga J, Beekman FJ, Goorden MC. Characterization of a multi-pinhole molecular breast tomosynthesis scanner. Phys Med Biol 2020; 65:195010. [PMID: 32570222 DOI: 10.1088/1361-6560/ab9eff] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In recent years, breast imaging using radiolabelled molecules has attracted significant interest. Our group has proposed a multi-pinhole molecular breast tomosynthesis (MP-MBT) scanner to obtain 3D functional molecular breast images at high resolutions. After conducting extensive optimisation studies using simulations, we here present a first prototype of MP-MBT and evaluate its performance using physical phantoms. The MP-MBT design is based on two opposing gamma cameras that can image a lightly compressed pendant breast. Each gamma camera consists of a 250 × 150 mm2 detector equipped with a collimator with multiple pinholes focusing on a line. The NaI(Tl) gamma detector is a customised design with 3.5 mm intrinsic spatial resolution and high spatial linearity near the edges due to a novel light-guide geometry and the use of square PMTs. A volume-of-interest is scanned by translating the collimator and gamma detector together in a sequence that optimises count yield from the scan region. Derenzo phantom images showed that the system can reach 3.5 mm resolution for a clinically realistic 99mTc activity concentration in an 11-minute scan, while in breast phantoms the smallest spheres visible were 6 mm in diameter for the same scan time. To conclude, the experimental results of the novel MP-MBT scanner showed that the setup had sub-centimetre breast tumour detection capability which might facilitate 3D molecular breast cancer imaging in the future.
Collapse
Affiliation(s)
- Beien Wang
- Section of Biomedical Imaging, Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15 2629 JB, Delft, The Netherlands
| | | | | | | | | | | |
Collapse
|
16
|
Ozsahin I, Chen L, Könik A, King MA, Beekman FJ, Mok GSP. The clinical utilities of multi-pinhole single photon emission computed tomography. Quant Imaging Med Surg 2020; 10:2006-2029. [PMID: 33014732 PMCID: PMC7495312 DOI: 10.21037/qims-19-1036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 07/30/2020] [Indexed: 11/06/2022]
Abstract
Single photon emission computed tomography (SPECT) is an important imaging modality for various applications in nuclear medicine. The use of multi-pinhole (MPH) collimators can provide superior resolution-sensitivity trade-off when imaging small field-of-view compared to conventional parallel-hole and fan-beam collimators. Besides the very successful application in small animal imaging, there has been a resurgence of the use of MPH collimators for clinical cardiac and brain studies, as well as other small field-of-view applications. This article reviews the basic principles of MPH collimators and introduces currently available and proposed clinical MPH SPECT systems.
Collapse
Affiliation(s)
- Ilker Ozsahin
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
- Department of Biomedical Engineering, Faculty of Engineering, Near East University, Nicosia/TRNC, Mersin-10, Turkey
- DESAM Institute, Near East University, Nicosia/TRNC, Mersin-10, Turkey
| | - Ling Chen
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | - Arda Könik
- Department of Imaging, Dana Farber Cancer Institute, Boston, MA, USA
| | - Michael A. King
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Freek J. Beekman
- Section of Biomedical Imaging, Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands
- MILabs B.V, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, The Netherlands
| | - Greta S. P. Mok
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau, China
- Center for Cognitive and Brain Sciences, Institute of Collaborative Innovation, University of Macau, Macau, China
| |
Collapse
|
17
|
Nguyen MP, Ramakers RM, Kamphuis C, Koustoulidou S, Goorden MC, Beekman FJ. EXIRAD-3D: Fast automated three-dimensional autoradiography. Nucl Med Biol 2020; 86-87:59-65. [DOI: 10.1016/j.nucmedbio.2020.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/15/2020] [Accepted: 06/02/2020] [Indexed: 12/12/2022]
|
18
|
Goorden MC, Kamphuis C, Ramakers RM, Beekman FJ. Accelerated image reconstruction by a combined dual-matrix dual-voxel approach. ACTA ACUST UNITED AC 2020; 65:105014. [DOI: 10.1088/1361-6560/ab82e9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
19
|
Chen Y, Goorden MC, Vastenhouw B, Beekman FJ. Optimized sampling for high resolution multi-pinhole brain SPECT with stationary detectors. ACTA ACUST UNITED AC 2020; 65:015002. [DOI: 10.1088/1361-6560/ab5bc6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
20
|
Wang B, Kreuger R, Huizenga J, Beekman FJ, Goorden MC. Experimental Validation of a Gamma Detector With a Novel Light-Guide-PMT Geometry to Reduce Dead Edge Effects. IEEE Trans Radiat Plasma Med Sci 2020. [DOI: 10.1109/trpms.2019.2916386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
21
|
Nguyen MP, Goorden MC, Kamphuis C, Beekman FJ. Evaluation of pinhole collimator materials for micron-resolution ex vivo SPECT. ACTA ACUST UNITED AC 2019; 64:105017. [DOI: 10.1088/1361-6560/ab1618] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
22
|
Chen Y, Vastenhouw B, Wu C, Goorden MC, Beekman FJ. Optimized image acquisition for dopamine transporter imaging with ultra-high resolution clinical pinhole SPECT. ACTA ACUST UNITED AC 2018; 63:225002. [DOI: 10.1088/1361-6560/aae76c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
23
|
van Roosmalen J, Beekman FJ, Goorden MC. Comparison of fan beam, slit-slat and multi-pinhole collimators for molecular breast tomosynthesis. Phys Med Biol 2018; 63:105009. [PMID: 29676285 DOI: 10.1088/1361-6560/aabfa3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Recently, we proposed and optimized dedicated multi-pinhole molecular breast tomosynthesis (MBT) that images a lightly compressed breast. As MBT may also be performed with other types of collimators, the aim of this paper is to optimize MBT with fan beam and slit-slat collimators and to compare its performance to that of multi-pinhole MBT to arrive at a truly optimized design. Using analytical expressions, we first optimized fan beam and slit-slat collimator parameters to reach maximum sensitivity at a series of given system resolutions. Additionally, we performed full system simulations of a breast phantom containing several tumours for the optimized designs. We found that at equal system resolution the maximum achievable sensitivity increases from pinhole to slit-slat to fan beam collimation with fan beam and slit-slat MBT having on average a 48% and 20% higher sensitivity than multi-pinhole MBT. Furthermore, by inspecting simulated images and applying a tumour-to-background contrast-to-noise (TB-CNR) analysis, we found that slit-slat collimators underperform with respect to the other collimator types. The fan beam collimators obtained a similar TB-CNR as the pinhole collimators, but the optimum was reached at different system resolutions. For fan beam collimators, a 6-8 mm system resolution was optimal in terms of TB-CNR, while with pinhole collimation highest TB-CNR was reached in the 7-10 mm range.
Collapse
Affiliation(s)
- Jarno van Roosmalen
- Section Radiation, Detection and Medical Imaging, Delft University of Technology, Delft, Netherlands
| | | | | |
Collapse
|
24
|
de Visser HM, Korthagen NM, Müller C, Ramakers RM, Krijger GC, Lafeber FPJG, Beekman FJ, Mastbergen SC, Weinans H. Imaging of Folate Receptor Expressing Macrophages in the Rat Groove Model of Osteoarthritis: Using a New DOTA-Folate Conjugate. Cartilage 2018; 9:183-191. [PMID: 29096521 PMCID: PMC5871123 DOI: 10.1177/1947603517738073] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Objective To evaluate the presence and localization of folate receptor expressing macrophages in the rat groove model of osteoarthritis and determine the suitability of a new folate conjugate with albumin-binding entity (cm09) for in vivo SPECT (single-photon emission computed tomography) analysis. Design In male Wistar rats, local cartilage damage was induced in addition to a standard ( n = 10) or high-fat diet ( n = 6). After 12 weeks, 111In labeled folate conjugates were administered, and SPECT/CT (computed tomography) imaging was performed after 24 hours. Subsequently, osteoarthritis severity and folate receptor expression were assessed using (immuno)-histological sections. Results In vivo SPECT/CT imaging of the new folate conjugate (cm09) was as useful as a folate conjugate without albumin-binding entity in the groove model of osteoarthritis with less renal accumulation. Induction of cartilage damage on a standard diet resulted in no effect on the amount of folate receptor expressing macrophages compared with the contralateral sham operated joints. In contrast, inducing cartilage damage in the high-fat diet group resulted in 28.4% increase of folate receptor expression as compared with the nondamaged control joints. Folate receptor expressing cells were predominantly present in the synovial lining and in subchondral bone as confirmed by immunohistochemistry. Conclusions Folate receptor expression, and thus macrophage activation, can clearly be demonstrated in vivo, in small animal models of osteoarthritis using the new 111In-folate conjugate with specific binding to the folate receptor. Increased macrophage activity only plays a role in the groove model of osteoarthritis when applied in a high-fat diet induced dysmetabolic condition, which is in line with the higher inflammatory state of that specific model.
Collapse
Affiliation(s)
- Huub M. de Visser
- Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands,Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Nicoline M. Korthagen
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands,Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Cristina Müller
- Centre for Radiopharmaceutical Sciences ETH-PSI-USZ, Paul Scherrer Institute, Villigen-PSI, Switzerland
| | - Ruud M. Ramakers
- MILabs B.V., Utrecht, The Netherlands,Section of Radiation, Detection & Medical Imaging, Applied Sciences, Delft University of Technology, Delft, The Netherlands,Department for Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gerard C. Krijger
- Department of Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Floris P. J. G. Lafeber
- Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Freek J. Beekman
- MILabs B.V., Utrecht, The Netherlands,Section of Radiation, Detection & Medical Imaging, Applied Sciences, Delft University of Technology, Delft, The Netherlands,Department for Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Simon C. Mastbergen
- Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands,Simon C. Mastbergen, Department of Rheumatology & Clinical Immunology, UMC Utrecht, F.02.127, PO Box 85500, 3508 GA Utrecht, The Netherlands.
| | - Harrie Weinans
- Department of Rheumatology and Clinical Immunology, University Medical Center Utrecht, Utrecht, The Netherlands,Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands,Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands
| |
Collapse
|
25
|
van Roosmalen J, Beekman FJ, Goorden MC. System geometry optimization for molecular breast tomosynthesis with focusing multi-pinhole collimators. Phys Med Biol 2017; 63:015018. [PMID: 28994663 DOI: 10.1088/1361-6560/aa9265] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Imaging of 99mTc-labelled tracers is gaining popularity for detecting breast tumours. Recently, we proposed a novel design for molecular breast tomosynthesis (MBT) based on two sliding focusing multi-pinhole collimators that scan a modestly compressed breast. Simulation studies indicate that MBT has the potential to improve the tumour-to-background contrast-to-noise ratio significantly over state-of-the-art planar molecular breast imaging. The aim of the present paper is to optimize the collimator-detector geometry of MBT. Using analytical models, we first optimized sensitivity at different fixed system resolutions (ranging from 5 to 12 mm) by tuning the pinhole diameters and the distance between breast and detector for a whole series of automatically generated multi-pinhole designs. We evaluated both MBT with a conventional continuous crystal detector with 3.2 mm intrinsic resolution and with a pixelated detector with 1.6 mm pixels. Subsequently, full system simulations of a breast phantom containing several lesions were performed for the optimized geometry at each system resolution for both types of detector. From these simulations, we found that tumour-to-background contrast-to-noise ratio was highest for systems in the 7 mm-10 mm system resolution range over which it hardly varied. No significant differences between the two detector types were found.
Collapse
Affiliation(s)
- Jarno van Roosmalen
- Section Biomedical Imaging, Delft University of Technology, Delft, Netherlands
| | | | | |
Collapse
|
26
|
Wang B, van Roosmalen J, Piët L, van Schie MA, Beekman FJ, Goorden MC. Voxelized ray-tracing simulation dedicated to multi-pinhole molecular breast tomosynthesis. Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa8012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|
27
|
van der Have F, Ivashchenko O, Goorden MC, Ramakers RM, Beekman FJ. High-resolution clustered pinhole 131Iodine SPECT imaging in mice. Nucl Med Biol 2016; 43:506-11. [DOI: 10.1016/j.nucmedbio.2016.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 05/12/2016] [Accepted: 05/28/2016] [Indexed: 11/25/2022]
|
28
|
Abstract
Planar molecular breast imaging (MBI) is rapidly gaining in popularity in diagnostic oncology. To add 3D capabilities, we introduce a novel molecular breast tomosynthesis (MBT) scanner concept based on multi-pinhole collimation. In our design, the patient lies prone with the pendant breast lightly compressed between transparent plates. Integrated webcams view the breast through these plates and allow the operator to designate the scan volume (e.g. a whole breast or a suspected region). The breast is then scanned by translating focusing multi-pinhole plates and NaI(Tl) gamma detectors together in a sequence that optimizes count yield from the volume-of-interest. With simulations, we compared MBT with existing planar MBI. In a breast phantom containing different lesions, MBT improved tumour-to-background contrast-to-noise ratio (CNR) over planar MBI by 12% and 111% for 4.0 and 6.0 mm lesions respectively in case of whole breast scanning. For the same lesions, much larger CNR improvements of 92% and 241% over planar MBI were found in a scan that focused on a breast region containing several lesions. MBT resolved 3.0 mm rods in a Derenzo resolution phantom in the transverse plane compared to 2.5 mm rods distinguished by planar MBI. While planar MBI cannot provide depth information, MBT offered 4.0 mm depth resolution. Our simulations indicate that besides offering 3D localization of increased tracer uptake, multi-pinhole MBT can significantly increase tumour-to-background CNR compared to planar MBI. These properties could be promising for better estimating the position, extend and shape of lesions and distinguishing between single and multiple lesions.
Collapse
Affiliation(s)
- Jarno van Roosmalen
- Section Radiation, Detection & Medical Imaging, Delft University of Technology, Delft, The Netherlands
| | | | | |
Collapse
|
29
|
Jennings L, Ivashchenko O, Marsman IJC, Laan AC, Denkova AG, Waton G, Beekman FJ, Schosseler F, Mendes E. In vivo biodistribution of stable spherical and filamentous micelles probed by high-sensitivity SPECT. Biomater Sci 2016; 4:1202-11. [PMID: 27286085 DOI: 10.1039/c6bm00297h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Understanding how nanoparticle properties such as size, morphology and rigidity influence their circulation time and biodistribution is essential for the development of nanomedicine therapies. Herein we assess the influence of morphology on cellular internalization, in vivo biodistribution and circulation time of nanocarriers using polystyrene-b-poly(ethylene oxide) micelles of spherical or elongated morphology. The glassy nature of polystyrene guarantees the morphological stability of the carriers in vivo and by encapsulating Indium-111 in their core, an assessment of the longitudinal in vivo biodistribution of the particles in healthy mice is performed with single photon emission computed tomography imaging. Our results show prolonged blood circulation, longer than 24 hours, for all micelle morphologies studied. Dynamics of micelle accumulation in the liver and other organs of the reticuloendothelial system show a size-dependent nature and late stage liver clearance is observed for the elongated morphology. Apparent contradictions between recent similar studies can be resolved by considering the effects of flexibility and degradation of the elongated micelles on their circulation time and biodistribution.
Collapse
Affiliation(s)
- L Jennings
- Institut Charles Sadron (CNRS), University of Strasbourg, Strasbourg, France.
| | | | | | | | | | | | | | | | | |
Collapse
|
30
|
|
31
|
Goorden MC, van Roosmalen J, van der Have F, Beekman FJ. Optimizing modelling in iterative image reconstruction for preclinical pinhole PET. Phys Med Biol 2016; 61:3712-33. [DOI: 10.1088/0031-9155/61/10/3712] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
32
|
Arranja A, Ivashchenko O, Denkova AG, Morawska K, van Vlierberghe S, Dubruel P, Waton G, Beekman FJ, Schosseler F, Mendes E. SPECT/CT Imaging of Pluronic Nanocarriers with Varying Poly(ethylene oxide) Block Length and Aggregation State. Mol Pharm 2016; 13:1158-65. [PMID: 26883169 DOI: 10.1021/acs.molpharmaceut.5b00958] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Optimal biodistribution and prolonged circulation of nanocarriers improve diagnostic and therapeutic effects of enhanced permeability and retention-based nanomedicines. Despite extensive use of Pluronics in polymer-based pharmaceuticals, the influence of different poly(ethylene oxide) (PEO) block length and aggregation state on the biodistribution of the carriers is rather unexplored. In this work, we studied these effects by evaluating the biodistribution of Pluronic unimers and cross-linked micelles with different PEO block size. In vivo biodistribution of (111)In-radiolabeled Pluronic nanocarriers was investigated in healthy mice using single photon emission computed tomography. All carriers show fast uptake in the organs from the reticuloendothelial system followed by a steady elimination through the hepatobiliary tract and renal filtration. The PEO block length affects the initial renal clearance of the compounds and the overall liver uptake. The aggregation state influences the long-term accumulation of the nanocarriers in the liver. We showed that the circulation time and elimination pathways can be tuned by varying the physicochemical properties of Pluronic copolymers. Our results can be beneficial for the design of future Pluronic-based nanomedicines.
Collapse
Affiliation(s)
- Alexandra Arranja
- Institut Charles Sadron (CNRS), Strasbourg, France.,Department of Radiation Science and Technology, Delft University of Technology , 2629 JB Delft, The Netherlands
| | - Oleksandra Ivashchenko
- Department of Radiation Science and Technology, Delft University of Technology , 2629 JB Delft, The Netherlands.,MILabs B.V., 3584 CX Utrecht, The Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center , 3584 CG Utrecht, The Netherlands
| | - Antonia G Denkova
- Department of Radiation Science and Technology, Delft University of Technology , 2629 JB Delft, The Netherlands
| | - Karolina Morawska
- Department of Organic and Macromolecular Chemistry, Ghent University , B-9000 Ghent, Belgium
| | - Sandra van Vlierberghe
- Department of Organic and Macromolecular Chemistry, Ghent University , B-9000 Ghent, Belgium
| | - Peter Dubruel
- Department of Organic and Macromolecular Chemistry, Ghent University , B-9000 Ghent, Belgium
| | - Gilles Waton
- Institut Charles Sadron (CNRS), Strasbourg, France
| | - Freek J Beekman
- Department of Radiation Science and Technology, Delft University of Technology , 2629 JB Delft, The Netherlands.,MILabs B.V., 3584 CX Utrecht, The Netherlands.,Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center , 3584 CG Utrecht, The Netherlands
| | | | - Eduardo Mendes
- Department of Chemical Engineering, Delft University of Technology , 2628 BL Delft, The Netherlands
| |
Collapse
|
33
|
de Swart J, Chan HS, Goorden MC, Morgenstern A, Bruchertseifer F, Beekman FJ, de Jong M, Konijnenberg MW. Utilizing High-Energy γ-Photons for High-Resolution 213Bi SPECT in Mice. J Nucl Med 2015; 57:486-92. [DOI: 10.2967/jnumed.115.157685] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
34
|
Ivashchenko O, van der Have F, Villena JL, Groen HC, Ramakers RM, Weinans HH, Beekman FJ. Quarter-millimeter-resolution molecular mouse imaging with U-SPECT⁺. Mol Imaging 2015; 13. [PMID: 25429783 DOI: 10.2310/7290.2014.00053] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Limited spatial resolution of preclinical positron emission tomography (PET) and single-photon emission computed tomography (SPECT) has slowed down applications of molecular imaging in small animals. Here we present the latest-generation U-SPECT system (U-SPECT⁺, MILabs, Utrecht, the Netherlands) enabling radionuclide imaging of mice with quarter-millimeter resolution. The system was equipped with the newest high-resolution collimator with 0.25 mm diameter circular pinholes. It was calibrated with technetium-99 m point source measurements from which the system matrix was calculated. Images were reconstructed using pixel-based ordered subset expectation maximization (OSEM). Various phantoms and mouse SPECT scans were acquired. The reconstructed spatial resolution (the smallest visible capillary diameter in a hot-rod resolution phantom) was 0.25 mm. Knee joint images show tiny structures such as the femur epicondyle sulcus, as well as a clear separation between cortical and trabecular bone structures. In addition, time-activity curves of the lumbar spine illustrated that tracer dynamics in tiny tissue amounts could be measured. U-SPECT⁺ allows discrimination between molecular concentrations in adjacent volumes of as small as 0.015 μL, which is significantly better than can be imaged by any existing SPECT or PET system. This increase in the level of detail makes it more and more attractive to replace ex vivo methods and allows monitoring biological processes in tiny parts of organs in vivo.
Collapse
|
35
|
Welling MM, Bunschoten A, Kuil J, Nelissen RGHH, Beekman FJ, Buckle T, van Leeuwen FWB. Development of a Hybrid Tracer for SPECT and Optical Imaging of Bacterial Infections. Bioconjug Chem 2015; 26:839-49. [PMID: 25853214 DOI: 10.1021/acs.bioconjchem.5b00062] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In trauma and orthopedic surgery, infection of implants has a major impact on the outcome for patients. Infections may develop either during the initial implantation or during the lifetime of an implant. Both infections, as well as aseptic loosening of the implant, are reasons for revision of the implants. Therefore, discrimination between aseptic-mechanical-loosening and septic-bacterial-loosening of implants is critical during selection of a patient-tailored treatment policy. Specific detection and visualization of infections is a challenge because it is difficult to discriminate infections from inflammation. An imaging tracer that facilitates bacterial identification in a pre- and intraoperative setting may aid the workup for patients suspicious of bacterial infections. In this study we evaluated an antimicrobial peptide conjugated to a hybrid label, which contains both a radioisotope and a fluorescent dye. After synthesis of DTPA-Cy5-UBI29-41 and-when necessary-radiolabeling with (111)In (yield 96.3 ± 2.7%), in vitro binding to various bacterial strains was evaluated using radioactivity counting and confocal fluorescence microscopy. Intramuscular bacterial infections (S. aureus or K. pneumoniae) were also visualized in vivo using a combined nuclear and fluorescence imaging system. The indium-111 was chosen as label as it has a well-defined coordination chemistry, and in pilot studies labeling DTPA-Cy5-UBI29-41 with technetium-99m, we encountered damage to the Cy5 dye after the reduction with SnCl2. As a reference, we used the validated tracer (99m)Tc-UBI29-41. Fast renal excretion of (111)In-DTPA-Cy5-UBI29-41 was observed. Target to nontarget (T/NT) ratios were highest at 2 h post injection: radioactivity counting yielded T/NT ratios of 2.82 ± 0.32 for S. aureus and 2.37 ± 0.05 for K. pneumoniae. Comparable T/NT ratios with fluorescence imaging of 2.38 ± 0.09 for S. aureus and 3.55 ± 0.31 for K. pneumoniae were calculated. Ex vivo confocal microscopy of excised infected tissues showed specific binding of the tracer to bacteria. Using a combination of nuclear and fluorescence imaging techniques, the hybrid antimicrobial peptide conjugate DTPA-Cy5-UBI29-41 was shown to specifically accumulate in bacterial infections. This hybrid tracer may facilitate integration of noninvasive identification of infections and their extent as well as real-time fluorescence guidance during surgical resection of infected areas.
Collapse
Affiliation(s)
| | | | | | | | - Freek J Beekman
- §Delft University of Technology, 2628 CD Delft, The Netherlands.,∥MILabs, 3584 CX Utrecht, The Netherlands
| | | | | |
Collapse
|
36
|
Abstract
UNLABELLED SPECT with submegabecquerel amounts of tracer or subsecond time resolution would enable a wide range of new imaging protocols such as screening tracers with initially low yield or labeling efficiency, imaging low receptor densities, or even performing SPECT outside regular radiation laboratories. To this end we developed dedicated ultra-high-sensitivity pinhole SPECT. METHODS A cylindric collimator with 54 focused 2.0-mm-diameter conical pinholes was manufactured and mounted in a stationary small-animal SPECT system. The system matrix for image reconstruction was calculated via a hybrid method based on both (99m)Tc point source measurements and ray-tracing analytic modeling. SPECT images were reconstructed using pixel-based ordered-subsets expectation maximization. Performance was evaluated with phantoms and low-dose bone, dynamic kidney, and cardiac mouse scans. RESULTS The peak sensitivity reached 1.3% (13,080 cps/MBq). The reconstructed spatial resolution (rod visibility in a micro-Jaszczak phantom) was 0.85 mm. Even with only a quarter megabecquerel of activity, 30-min bone SPECT scans provided surprisingly high levels of detail. Dynamic dual-isotope kidney and (99m)Tc-sestamibi cardiac scans were acquired with a time-frame resolution down to 1 s. CONCLUSION The high sensitivity achieved increases the range of mouse SPECT applications by enabling in vivo imaging with less than a megabecquerel of tracer activity or down to 1-s frame dynamics.
Collapse
Affiliation(s)
- Oleksandra Ivashchenko
- Section of Radiation, Detection, and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs B.V., Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Frans van der Have
- Section of Radiation, Detection, and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs B.V., Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Marlies C Goorden
- Section of Radiation, Detection, and Medical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Ruud M Ramakers
- Section of Radiation, Detection, and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs B.V., Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Freek J Beekman
- Section of Radiation, Detection, and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs B.V., Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
37
|
Lange R, de Klerk JMH, Bloemendal HJ, Ramakers RM, Beekman FJ, van der Westerlaken MML, Hendrikse NH, Ter Heine R. Drug composition matters: the influence of carrier concentration on the radiochemical purity, hydroxyapatite affinity and in-vivo bone accumulation of the therapeutic radiopharmaceutical 188Rhenium-HEDP. Nucl Med Biol 2015; 42:465-469. [PMID: 25662844 DOI: 10.1016/j.nucmedbio.2015.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 12/22/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022]
Abstract
INTRODUCTION (188)Rhenium-HEDP is an effective bone-targeting therapeutic radiopharmaceutical, for treatment of osteoblastic bone metastases. It is known that the presence of carrier (non-radioactive rhenium as ammonium perrhenate) in the reaction mixture during labeling is a prerequisite for adequate bone affinity, but little is known about the optimal carrier concentration. METHODS We investigated the influence of carrier concentration in the formulation on the radiochemical purity, in-vitro hydroxyapatite affinity and the in-vivo bone accumulation of (188)Rhenium-HEDP in mice. RESULTS The carrier concentration influenced hydroxyapatite binding in-vitro as well as bone accumulation in-vivo. Variation in hydroxyapatite binding with various carrier concentrations seemed to be mainly driven by variation in radiochemical purity. The in-vivo bone accumulation appeared to be more complex: satisfactory radiochemical purity and hydroxyapatite affinity did not necessarily predict acceptable bio-distribution of (188)Rhenium-HEDP. CONCLUSIONS For development of new bisphosphonate-based radiopharmaceuticals for clinical use, human administration should not be performed without previous animal bio-distribution experiments. Furthermore, our clinical formulation of (188)Rhenium-HEDP, containing 10 μmol carrier, showed excellent bone accumulation that was comparable to other bisphosphonate-based radiopharmaceuticals, with no apparent uptake in other organs. ADVANCES IN KNOWLEDGE Radiochemical purity and in-vitro hydroxyapatite binding are not necessarily predictive of bone accumulation of (188)Rhenium-HEDP in-vivo. IMPLICATIONS FOR PATIENT CARE The formulation for (188)Rhenium-HEDP as developed by us for clinical use exhibits excellent bone uptake and variation in carrier concentration during preparation of this radiopharmaceutical should be avoided.
Collapse
Affiliation(s)
- R Lange
- Meander Medical Center, Department of Clinical Pharmacy, Amersfoort, The Netherlands
| | - J M H de Klerk
- Meander Medical Center, Department of Radiology & Nuclear Medicine, Amersfoort, The Netherlands
| | - H J Bloemendal
- Meander Medical Center, Department of Internal Medicine, Amersfoort, The Netherlands
| | - R M Ramakers
- Section Radiation, Detection & Medical Imaging, TU Delft & MILabs B.V., Utrecht, The Netherlands
| | - F J Beekman
- Section Radiation, Detection & Medical Imaging, TU Delft & MILabs B.V., Utrecht, The Netherlands
| | | | - N H Hendrikse
- Department of Clinical Pharmacology & Pharmacy, VU University Medical Center, Amsterdam, The Netherlands
| | - R Ter Heine
- Meander Medical Center, Department of Clinical Pharmacy, Maatweg 3, 3813TZ, Amersfoort, The Netherlands.
| |
Collapse
|
38
|
Wu C, Vaissier PEB, Vastenhouw B, de Jong JR, Slart RHJA, Beekman FJ. Influence of respiratory gating, image filtering, and animal positioning on high-resolution electrocardiography-gated murine cardiac single-photon emission computed tomography. Mol Imaging 2014; 13. [PMID: 25429719 DOI: 10.2310/7290.2014.00052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Cardiac parameters obtained from single-photon emission computed tomographic (SPECT) images can be affected by respiratory motion, image filtering, and animal positioning. We investigated the influence of these factors on ultra-high-resolution murine myocardial perfusion SPECT. Five mice were injected with 99m technetium (99mTc)-tetrofosmin, and each was scanned in supine and prone positions in a U-SPECT-II scanner with respiratory and electrocardiographic (ECG) gating. ECG-gated SPECT images were created without applying respiratory motion correction or with two different respiratory motion correction strategies. The images were filtered with a range of three-dimensional gaussian kernels, after which end-diastolic volumes (EDVs), end-systolic volumes (ESVs), and left ventricular ejection fractions were calculated. No significant differences in the measured cardiac parameters were detected when any strategy to reduce or correct for respiratory motion was applied, whereas big differences (> 5%) in EDV and ESV were found with regard to different positioning of animals. A linear relationship (p < .001) was found between the EDV or ESV and the kernel size of the gaussian filter. In short, respiratory gating did not significantly affect the cardiac parameters of mice obtained with ultra-high-resolution SPECT, whereas the position of the animals and the image filters should be the same in a comparative study with multiple scans to avoid systematic differences in measured cardiac parameters.
Collapse
|
39
|
van Oosterom MN, Kreuger R, Buckle T, Mahn WA, Bunschoten A, Josephson L, van Leeuwen FW, Beekman FJ. U-SPECT-BioFluo: an integrated radionuclide, bioluminescence, and fluorescence imaging platform. EJNMMI Res 2014; 4:56. [PMID: 25386389 PMCID: PMC4209452 DOI: 10.1186/s13550-014-0056-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 09/28/2014] [Indexed: 01/11/2023] Open
Abstract
Background In vivo bioluminescence, fluorescence, and single-photon emission computed tomography (SPECT) imaging provide complementary information about biological processes. However, to date these signatures are evaluated separately on individual preclinical systems. In this paper, we introduce a fully integrated bioluminescence-fluorescence-SPECT platform. Next to an optimization in logistics and image fusion, this integration can help improve understanding of the optical imaging (OI) results. Methods An OI module was developed for a preclinical SPECT system (U-SPECT, MILabs, Utrecht, the Netherlands). The applicability of the module for bioluminescence and fluorescence imaging was evaluated in both a phantom and in an in vivo setting using mice implanted with a 4 T1-luc + tumor. A combination of a fluorescent dye and radioactive moiety was used to directly relate the optical images of the module to the SPECT findings. Bioluminescence imaging (BLI) was compared to the localization of the fluorescence signal in the tumors. Results Both the phantom and in vivo mouse studies showed that superficial fluorescence signals could be imaged accurately. The SPECT and bioluminescence images could be used to place the fluorescence findings in perspective, e.g. by showing tracer accumulation in non-target organs such as the liver and kidneys (SPECT) and giving a semi-quantitative read-out for tumor spread (bioluminescence). Conclusions We developed a fully integrated multimodal platform that provides complementary registered imaging of bioluminescent, fluorescent, and SPECT signatures in a single scanning session with a single dose of anesthesia. In our view, integration of these modalities helps to improve data interpretation of optical findings in relation to radionuclide images.
Collapse
Affiliation(s)
- Matthias N van Oosterom
- Radiation, Detection and Medical Imaging, Delft University of Technology, Mekelweg 15, Delft, 2629, JB, the Netherlands ; Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Rob Kreuger
- Radiation, Detection and Medical Imaging, Delft University of Technology, Mekelweg 15, Delft, 2629, JB, the Netherlands
| | - Tessa Buckle
- Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Wendy A Mahn
- Radiation, Detection and Medical Imaging, Delft University of Technology, Mekelweg 15, Delft, 2629, JB, the Netherlands
| | - Anton Bunschoten
- Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Lee Josephson
- Centre for Translational Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | - Fijs Wb van Leeuwen
- Interventional Molecular Imaging Laboratory, Department of Radiology, Leiden University Medical Center, Leiden, the Netherlands
| | - Freek J Beekman
- Radiation, Detection and Medical Imaging, Delft University of Technology, Mekelweg 15, Delft, 2629, JB, the Netherlands ; MILABS, Utrecht, the Netherlands ; Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands
| |
Collapse
|
40
|
Walker MD, Goorden MC, Dinelle K, Ramakers RM, Blinder S, Shirmohammad M, van der Have F, Beekman FJ, Sossi V. Performance assessment of a preclinical PET scanner with pinhole collimation by comparison to a coincidence-based small-animal PET scanner. J Nucl Med 2014; 55:1368-74. [PMID: 24904110 DOI: 10.2967/jnumed.113.136663] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/21/2014] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED PET imaging of rodents is increasingly used in preclinical research, but its utility is limited by spatial resolution and signal-to-noise ratio of the images. A recently developed preclinical PET system uses a clustered-pinhole collimator, enabling high-resolution, simultaneous imaging of PET and SPECT tracers. Pinhole collimation strongly departs from traditional electronic collimation achieved via coincidence detection in PET. We investigated the potential of such a design by direct comparison to a traditional PET scanner. METHODS Two small-animal PET scanners, 1 with electronic collimation and 1 with physical collimation using clustered pinholes, were used to acquire data from Jaszczak (hot rod) and uniform phantoms. Mouse brain imaging using (18)F-FDG PET was performed on each system and compared with quantitative ex vivo autoradiography as a gold standard. Bone imaging using (18)F-NaF allowed comparison of imaging in the mouse body. Images were visually and quantitatively compared using measures of contrast and noise. RESULTS Pinhole PET resolved the smallest rods (diameter, 0.85 mm) in the Jaszczak phantom, whereas the coincidence system resolved 1.1-mm-diameter rods. Contrast-to-noise ratios were better for pinhole PET when imaging small rods (<1.1 mm) for a wide range of activity levels, but this reversed for larger rods. Image uniformity on the coincidence system (<3%) was superior to that on the pinhole system (5%). The high (18)F-FDG uptake in the striatum of the mouse brain was fully resolved using the pinhole system, with contrast to nearby regions equaling that from autoradiography; a lower contrast was found using the coincidence PET system. For short-duration images (low-count), the coincidence system was superior. CONCLUSION In the cases for which small regions need to be resolved in scans with reasonably high activity or reasonably long scan times, a first-generation clustered-pinhole system can provide image quality in terms of resolution, contrast, and the contrast-to-noise ratio superior to a traditional PET system.
Collapse
Affiliation(s)
- Matthew D Walker
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Marlies C Goorden
- Section Radiation, Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Katherine Dinelle
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ruud M Ramakers
- Section Radiation, Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs, Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Stephan Blinder
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Maryam Shirmohammad
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Frans van der Have
- Section Radiation, Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs, Utrecht, The Netherlands; and
| | - Freek J Beekman
- Section Radiation, Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands MILabs, Utrecht, The Netherlands; and Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| |
Collapse
|
41
|
Bernsen MR, Vaissier PEB, Van Holen R, Booij J, Beekman FJ, de Jong M. The role of preclinical SPECT in oncological and neurological research in combination with either CT or MRI. Eur J Nucl Med Mol Imaging 2014; 41 Suppl 1:S36-49. [PMID: 24895751 PMCID: PMC4003405 DOI: 10.1007/s00259-013-2685-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 01/03/2023]
Abstract
Preclinical imaging with SPECT combined with CT or MRI is used more and more frequently and has proven to be very useful in translational research. In this article, an overview of current preclinical research applications and trends of SPECT combined with CT or MRI, mainly in tumour imaging and neuroscience imaging, is given and the advantages and disadvantages of the different approaches are described. Today SPECT and CT systems are often integrated into a single device (commonly called a SPECT/CT system), whereas at present combined SPECT and MRI is almost always carried out with separate systems and fiducial markers to combine the separately acquired images. While preclinical SPECT/CT is most widely applied in oncology research, SPECT combined with MRI (SPECT/MRI when integrated in one system) offers the potential for both neuroscience applications and oncological applications. Today CT and MRI are still mainly used to localize radiotracer binding and to improve SPECT quantification, although both CT and MRI have additional potential. Future technology developments may include fast sequential or simultaneous acquisition of (dynamic) multimodality data, spectroscopy, fMRI along with high-resolution anatomic MRI, advanced CT procedures, and combinations of more than two modalities such as combinations of SPECT, PET, MRI and CT all together. This will all strongly depend on new technologies. With further advances in biology and chemistry for imaging molecular targets and (patho)physiological processes in vivo, the introduction of new imaging procedures and promising new radiopharmaceuticals in clinical practice may be accelerated.
Collapse
Affiliation(s)
- Monique R. Bernsen
- Department of Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology, Erasmus MC, Rotterdam, The Netherlands
| | - Pieter E. B. Vaissier
- Section Radiation Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands
| | - Roel Van Holen
- ELIS Department, MEDISIP, Ghent University, iMinds, Ghent, Belgium
| | - Jan Booij
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Freek J. Beekman
- Section Radiation Detection and Medical Imaging, Delft University of Technology, Delft, The Netherlands
- MILabs B.V., Utrecht, The Netherlands
| | - Marion de Jong
- Department of Nuclear Medicine, Erasmus MC, Rotterdam, The Netherlands
- Department of Radiology, Erasmus MC, Rotterdam, The Netherlands
| |
Collapse
|
42
|
Branderhorst W, Blezer ELA, Houtkamp M, Ramakers RM, van den Brakel JH, Witteveen H, van der Have F, Gratama van Andel HA, Vastenhouw B, Wu C, Walsum MSV, van Dongen GAMS, Viergever MA, Bleeker WK, Beekman FJ. Three-dimensional histologic validation of high-resolution SPECT of antibody distributions within xenografts. J Nucl Med 2014; 55:830-7. [PMID: 24686779 DOI: 10.2967/jnumed.113.125401] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Longitudinal imaging of intratumoral distributions of antibodies in vivo in mouse cancer models is of great importance for developing cancer therapies. In this study, multipinhole SPECT with sub-half-millimeter resolution was tested for exploring intratumoral distributions of radiolabeled antibodies directed toward the epidermal growth factor receptor (EGFr) and compared with full 3-dimensional target expression assessed by immunohistochemistry. METHODS (111)In-labeled zalutumumab, a human monoclonal human EGFr-targeting antibody, was administered at a nonsaturating dose to 3 mice with xenografted A431 tumors exhibiting high EGFr expression. Total-body and focused in vivo tumor SPECT was performed at 0 and 48 h after injection and compared both visually and quantitatively with full 3-dimensional immunohistochemical staining for EGFr target expression. RESULTS SPECT at 48 h after injection showed that activity was predominantly concentrated in the tumor (10.5% ± 1.3% of the total-body activity; average concentration, 30.1% ± 4.6% of the injected dose per cubic centimeter). (111)In-labeled EGFr-targeting antibodies were distributed heterogeneously throughout the tumor. Some hot spots were observed near the tumor rim. Immunohistochemistry indicated that the antibody distributions obtained by SPECT were morphologically similar to those obtained for ex vivo EGFr target expression. Regions showing low SPECT activity were necrotic or virtually negative for EGFr target expression. A good correlation (r = 0.86, P < 0.0001) was found between the percentage of regions showing low activity on SPECT and the percentage of necrotic tissue on immunohistochemistry. CONCLUSION Multipinhole SPECT enables high-resolution visualization and quantification of the heterogeneity of (111)In-zalutumumab concentrations in vivo.
Collapse
Affiliation(s)
- Woutjan Branderhorst
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
43
|
Vaissier PEB, Goorden MC, Taylor AB, Beekman FJ. Fast Count-Regulated OSEM Reconstruction With Adaptive Resolution Recovery. IEEE Trans Med Imaging 2013; 32:2250-2261. [PMID: 23996543 DOI: 10.1109/tmi.2013.2279851] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Ordered subsets expectation maximization (OSEM) is widely used to accelerate tomographic reconstruction. Speed-up of OSEM over maximum likelihood expectation maximization (MLEM) is close to the number of subsets (NS). Recently we significantly increased the speed-up achievable with OSEM by specific subset choice (pixel-based OSEM). However, a high NS can cause undesirable noise levels, quantitative inaccuracy or even disappearance of lesions in low-activity image regions, while a low NS leads to prohibitively long reconstructions or unrecovered details in highly active regions. Here, we introduce count-regulated OSEM (CROSEM) which locally adapts the effective NS based on the estimated amount of detected photons originating from individual voxels. CROSEM was tested using multi-pinhole SPECT simulations and in vivo imaging. With the maximum NS set to 128, CROSEM attained acceleration factors close to 128 in high-activity regions and kept quantitative accuracy in low-activity regions close to that of MLEM. At equal cold-lesion contrast in high-activity regions, CROSEM exhibited lower noise than MLEM in low-activity regions. CROSEM is a fast and stable alternative to OSEM, preventing excessive image noise and quantitative errors in low-activity regions while achieving high-resolution recovery in structures with high activity uptake.
Collapse
|
44
|
Nuyts J, De Man B, Fessler JA, Zbijewski W, Beekman FJ. Modelling the physics in the iterative reconstruction for transmission computed tomography. Phys Med Biol 2013. [PMID: 23739261 DOI: 10.1088/0031‐9155/58/12/r63] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
There is an increasing interest in iterative reconstruction (IR) as a key tool to improve quality and increase applicability of x-ray CT imaging. IR has the ability to significantly reduce patient dose; it provides the flexibility to reconstruct images from arbitrary x-ray system geometries and allows one to include detailed models of photon transport and detection physics to accurately correct for a wide variety of image degrading effects. This paper reviews discretization issues and modelling of finite spatial resolution, Compton scatter in the scanned object, data noise and the energy spectrum. The widespread implementation of IR with a highly accurate model-based correction, however, still requires significant effort. In addition, new hardware will provide new opportunities and challenges to improve CT with new modelling.
Collapse
Affiliation(s)
- Johan Nuyts
- Department of Nuclear Medicine and Medical Imaging Research Center, KU Leuven, Leuven, Belgium.
| | | | | | | | | |
Collapse
|
45
|
Abstract
There is an increasing interest in iterative reconstruction (IR) as a key tool to improve quality and increase applicability of x-ray CT imaging. IR has the ability to significantly reduce patient dose; it provides the flexibility to reconstruct images from arbitrary x-ray system geometries and allows one to include detailed models of photon transport and detection physics to accurately correct for a wide variety of image degrading effects. This paper reviews discretization issues and modelling of finite spatial resolution, Compton scatter in the scanned object, data noise and the energy spectrum. The widespread implementation of IR with a highly accurate model-based correction, however, still requires significant effort. In addition, new hardware will provide new opportunities and challenges to improve CT with new modelling.
Collapse
Affiliation(s)
- Johan Nuyts
- Department of Nuclear Medicine and Medical Imaging Research Center, KU Leuven, Leuven, Belgium.
| | | | | | | | | |
Collapse
|
46
|
Abstract
Scintillation gamma cameras based on low-noise electron multiplication (EM-)CCDs can reach high spatial resolutions. For further improvement of these gamma cameras, more insight is needed into how various parameters that characterize these devices influence their performance. Here, we use the Cramer-Rao lower bound (CRLB) to investigate the sensitivity of the energy and spatial resolution of an EM-CCD-based gamma camera to several parameters. The gamma camera setup consists of a 3 mm thick CsI(Tl) scintillator optically coupled by a fiber optic plate to the E2V CCD97 EM-CCD. For this setup, the position and energy of incoming gamma photons are determined with a maximum-likelihood detection algorithm. To serve as the basis for the CRLB calculations, accurate models for the depth-dependent scintillation light distribution are derived and combined with a previously validated statistical response model for the EM-CCD. The sensitivity of the lower bounds for energy and spatial resolution to the EM gain and the depth-of-interaction (DOI) are calculated and compared to experimentally obtained values. Furthermore, calculations of the influence of the number of detected optical photons and noise sources in the image area on the energy and spatial resolution are presented. Trends predicted by CRLB calculations agree with experiments, although experimental values for spatial and energy resolution are typically a factor of 1.5 above the calculated lower bounds. Calculations and experiments both show that an intermediate EM gain setting results in the best possible spatial or energy resolution and that the spatial resolution of the gamma camera degrades rapidly as a function of the DOI. Furthermore, calculations suggest that a large improvement in gamma camera performance is achieved by an increase in the number of detected photons or a reduction of noise in the image area. A large noise reduction, as is possible with a new generation of EM-CCD electronics, may improve the energy and spatial resolution by a factor of 1.5.
Collapse
Affiliation(s)
- Marc A N Korevaar
- Section of Radiation Detection and Medical Imaging, Department of Radiation, Radionuclides and Reactors, Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft, The Netherlands.
| | | | | |
Collapse
|
47
|
Wu C, Gratama van Andel HA, Laverman P, Boerman OC, Beekman FJ. Effects of attenuation map accuracy on attenuation-corrected micro-SPECT images. EJNMMI Res 2013; 3:7. [PMID: 23369630 PMCID: PMC3579699 DOI: 10.1186/2191-219x-3-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 01/23/2013] [Indexed: 12/18/2022] Open
Abstract
Background In single-photon emission computed tomography (SPECT), attenuation of photon flux in tissue affects quantitative accuracy of reconstructed images. Attenuation maps derived from X-ray computed tomography (CT) can be employed for attenuation correction. The attenuation coefficients as well as registration accuracy between SPECT and CT can be influenced by several factors. Here we investigate how such inaccuracies influence micro-SPECT quantification. Methods Effects of (1) misalignments between micro-SPECT and micro-CT through shifts and rotation, (2) globally altered attenuation coefficients and (3) combinations of these were evaluated. Tests were performed with a NEMA NU 4–2008 phantom and with rat cadavers containing sources with known activity. Results Changes in measured activities within volumes of interest in phantom images ranged from <1.5% (125I) and <0.6% (201Tl, 99mTc and 111In) for 1-mm shifts to <4.5% (125I) and <1.7% (201Tl, 99mTc and 111In) with large misregistration (3 mm). Changes induced by 15° rotation were smaller than those by 3-mm shifts. By significantly altering attenuation coefficients (±10%), activity changes of <5.2% for 125I and <2.7% for 201Tl, 99mTc and 111In were induced. Similar trends were seen in rat studies. Conclusions While getting sufficient accuracy of attenuation maps in clinical imaging is highly challenging, our results indicate that micro-SPECT quantification is quite robust to various imperfections of attenuation maps.
Collapse
Affiliation(s)
- Chao Wu
- Section Radiation, Detection & Medical Imaging, Delft University of Technology, Mekelweg 15, Delft, 2629 JB, the Netherlands.
| | | | | | | | | |
Collapse
|
48
|
Bult W, Kroeze SGC, Elschot M, Seevinck PR, Beekman FJ, de Jong HWAM, Uges DRA, Kosterink JGW, Luijten PR, Hennink WE, van het Schip AD, Bosch JLHR, Nijsen JFW, Jans JJM. Intratumoral administration of holmium-166 acetylacetonate microspheres: antitumor efficacy and feasibility of multimodality imaging in renal cancer. PLoS One 2013; 8:e52178. [PMID: 23320070 PMCID: PMC3540022 DOI: 10.1371/journal.pone.0052178] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 11/12/2012] [Indexed: 01/01/2023] Open
Abstract
Purpose The increasing incidence of small renal tumors in an aging population with comorbidities has stimulated the development of minimally invasive treatments. This study aimed to assess the efficacy and demonstrate feasibility of multimodality imaging of intratumoral administration of holmium-166 microspheres (166HoAcAcMS). This new technique locally ablates renal tumors through high-energy beta particles, while the gamma rays allow for nuclear imaging and the paramagnetism of holmium allows for MRI. Methods 166HoAcAcMS were administered intratumorally in orthotopic renal tumors (Balb/C mice). Post administration CT, SPECT and MRI was performed. At several time points (2 h, 1, 2, 3, 7 and 14 days) after MS administration, tumors were measured and histologically analyzed. Holmium accumulation in organs was measured using inductively coupled plasma mass spectrometry. Results 166HoAcAcMS were successfully administered to tumor bearing mice. A striking near-complete tumor-control was observed in 166HoAcAcMS treated mice (0.10±0.01 cm3 vs. 4.15±0.3 cm3 for control tumors). Focal necrosis and inflammation was present from 24 h following treatment. Renal parenchyma outside the radiated region showed no histological alterations. Post administration CT, MRI and SPECT imaging revealed clear deposits of 166HoAcAcMS in the kidney. Conclusions Intratumorally administered 166HoAcAcMS has great potential as a new local treatment of renal tumors for surgically unfit patients. In addition to strong cancer control, it provides powerful multimodality imaging opportunities.
Collapse
Affiliation(s)
- Wouter Bult
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- Department of Hospital and Clinical Pharmacy, University Medical Center Groningen, Groningen, The Netherlands
| | - Stephanie G. C. Kroeze
- Department of Urology, University Medical Center Utrecht, Utrecht, The Netherlands
- Laboratory of Experimental Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mattijs Elschot
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter R. Seevinck
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Freek J. Beekman
- Milabs, Utrecht, The Netherlands
- Section Radiation Detection & Medical Imaging, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands
| | - Hugo W. A. M. de Jong
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Donald R. A. Uges
- Department of Hospital and Clinical Pharmacy, University Medical Center Groningen, Groningen, The Netherlands
| | - Jos G. W. Kosterink
- Department of Hospital and Clinical Pharmacy, University Medical Center Groningen, Groningen, The Netherlands
| | - Peter R. Luijten
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wim E. Hennink
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Alfred D. van het Schip
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - J. L. H. Ruud Bosch
- Department of Urology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - J. Frank W. Nijsen
- Imaging Division, Department of Radiology and Nuclear Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
| | - Judith J. M. Jans
- Department of Urology, University Medical Center Utrecht, Utrecht, The Netherlands
- Laboratory of Experimental Oncology, University Medical Center Utrecht, Utrecht, The Netherlands
| |
Collapse
|
49
|
Salvador S, Korevaar MAN, Heemskerk JWT, Kreuger R, Huizenga J, Seifert S, Schaart DR, Beekman FJ. Improved EMCCD gamma camera performance by SiPM pre-localization. Phys Med Biol 2012; 57:7709-24. [PMID: 23123792 DOI: 10.1088/0031-9155/57/22/7709] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
50
|
Goorden MC, van der Have F, Kreuger R, Ramakers RM, Vastenhouw B, Burbach JPH, Booij J, Molthoff CFM, Beekman FJ. VECTor: A Preclinical Imaging System for Simultaneous Submillimeter SPECT and PET. J Nucl Med 2012; 54:306-12. [PMID: 23077113 DOI: 10.2967/jnumed.112.109538] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|