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Cosmi V, Kvassheim M, Ghosh S, Beekman FJ, Goorden MC. Twisted clustered pinhole collimation for improved high-energy preclinical SPECT/PET. Phys Med Biol 2024; 69:225016. [PMID: 39533753 DOI: 10.1088/1361-6560/ad8c97] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 10/29/2024] [Indexed: 11/16/2024]
Abstract
Objective.Advanced pinhole collimation geometries optimized for preclinical high-energyɣimaging facilitate applications such asɑandßemitter imaging, simultaneous multi-isotope PET and PET/SPECT, and positron range-free PET. These geometries replace each pinhole with a group of clustered pinholes (CPs) featuring smaller individual pinhole opening angles (POAs), enabling sub-mm resolution imaging up to ∼1 MeV. Further narrowing POAs while retaining field-of-view (FOV) may enhance high-energy imaging but faces geometrical constraints. Here, we detail how the novel twisted CPs (TCPs) address this challenge.Approach.We compared TCP and CP collimator sensitivity at equal system resolution (SR) and SR at matched sensitivity by tuning pinhole diameters for18F (511 keV) and89Zr (909 keV). Additionally, simulated Derenzo phantoms at low activity (LA: 12 MBq ml-1) and high activity (HA: 190 MBq ml-1) levels, along with uniformity images, were compared to assess image resolution and uniformity.Main results.At equal SR, TCP increased average central FOV sensitivity by 15.6% for18F and 29.4% for89Zr compared to CP. Image resolution was comparable, except for89Zr at LA, where TCP resolved 0.80 mm diameter rods compared to 0.90 mm for CP. Image uniformity was equivalent for18F, while for89Zr TCP granted a 10.4% improvement. For collimators with matched sensitivity, TCP improved SR by 6.6% for18F and 17.7% for89Zr while also enhancing image resolution; for18F, rods distinguished were 0.65 mm (CP) and 0.60 mm (TCP) for HA, and 0.70 mm (CP and TCP) for LA. For89Zr, image resolutions were 0.75 mm (CP) and 0.65 mm (TCP) for HA, and 0.90 mm (CP) and 0.80 mm (TCP) for LA. Image uniformity with TCP decreased by 18.3% for18F but improved by 20.1% for89Zr.Significance.This study suggests that the TCP design has potential to improve high-energyɣimaging.
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Affiliation(s)
- Valerio Cosmi
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
| | - Monika Kvassheim
- Department of Physics and Computational Radiology, Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
- Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Satyajit Ghosh
- 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
| | - Marlies C Goorden
- Department of Radiation Science and Technology, Delft University of Technology, Delft, The Netherlands
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Gomes CV, Mendes BM, Paixão L, Gnesin S, Müller C, van der Meulen NP, Strobel K, Fonseca TCF, Lima TVM. Comparison of the dosimetry of scandium-43 and scandium-44 patient organ doses in relation to commonly used gallium-68 for imaging neuroendocrine tumours. EJNMMI Phys 2024; 11:61. [PMID: 39004681 PMCID: PMC11247068 DOI: 10.1186/s40658-024-00669-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 07/05/2024] [Indexed: 07/16/2024] Open
Abstract
BACKGROUND Several research groups have explored the potential of scandium radionuclides for theragnostic applications due to their longer half-lives and equal or similar coordination chemistry between their diagnostic and therapeutic counterparts, as well as lutetium-177 and terbium-161, respectively. Unlike the gallium-68/lutetium-177 pair, which may show different in-vivo uptake patterns, the use of scandium radioisotopes promises consistent behaviour between diagnostic and therapeutic radiopeptides. An advantage of scandium's longer half-life over gallium-68 is the ability to study radiopeptide uptake over extended periods and its suitability for centralized production and distribution. However, concerns arise from scandium-44's decay characteristics and scandium-43's high production costs. This study aimed to evaluate the dosimetric implications of using scandium radioisotopes with somatostatin analogues against gallium-68 for PET imaging of neuroendocrine tumours. METHODS Absorbed dose per injected activity (AD/IA) from the generated time-integrated activity curve (TIAC) were estimated using the radiopeptides [43/44/44mSc]Sc- and [68Ga]Ga-DOTATATE. The kidneys, liver, spleen, and red bone marrow (RBM) were selected for dose estimation studies. The EGSnrc and MCNP6.1 Monte Carlo (MC) codes were used with female (AF) and male (AM) ICRP phantoms. The results were compared to Olinda/EXM software, and the effective dose concentrations assessed, varying composition between the scandium radioisotopes. RESULTS Our findings showed good agreement between the MC codes, with - 3 ± 8% mean difference. Kidneys, liver, and spleen showed differences between the MC codes (min and max) in a range of - 4% to 8%. This was observed for both phantoms for all radiopeptides used in the study. Compared to Olinda/EXM the largest observed difference was for the RBM, of 21% for the AF and 16% for the AM for scandium- and gallium-based radiopeptides. Despite the differences, our findings showed a higher absorbed dose on [43/44Sc]Sc-DOTATATE compared to its 68Ga-based counterpart. CONCLUSION This study found that [43/44Sc]Sc-DOTATATE delivers a higher absorbed dose to organs at risk compared to [68Ga]Ga-DOTATATE, assuming equal distribution. This is due to the longer half-life of scandium radioisotopes compared to gallium-68. However, calculated doses are within acceptable ranges, making scandium radioisotopes a feasible replacement for gallium-68 in PET imaging, potentially offering enhanced diagnostic potential with later timepoint imaging.
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Affiliation(s)
- Carlos Vinícius Gomes
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012, Bern, Switzerland.
- Post-graduation Program in Nuclear Sciences and Techniques, Department of Nuclear Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil.
| | - Bruno Melo Mendes
- Nuclear Technology Development Center - CDTN/CNEN, Belo Horizonte, Brazil
| | - Lucas Paixão
- Department of Anatomy and Imaging, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Silvano Gnesin
- Institute of Radiation Physics, Lausanne University Hospital, University of Lausanne, Lausanne, Switzerland
| | - Cristina Müller
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - Nicholas P van der Meulen
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute (PSI), Villigen, Switzerland
- Laboratory of Radiochemistry, Paul Scherrer Institute (PSI), Villigen, Switzerland
| | - Klaus Strobel
- Institute of Radiology and Nuclear Medicine, Luzerner Kantonsspital - LUKS, Lucerne, Switzerland
| | - Telma Cristina Ferreira Fonseca
- Post-graduation Program in Nuclear Sciences and Techniques, Department of Nuclear Engineering, Federal University of Minas Gerais, Belo Horizonte, Brazil
- Nuclear Technology Development Center - CDTN/CNEN, Belo Horizonte, Brazil
| | - Thiago Viana Miranda Lima
- Institute of Radiology and Nuclear Medicine, Luzerner Kantonsspital - LUKS, Lucerne, Switzerland
- Faculty of Health Sciences and Medicine, University of Lucerne, Lucerne, Switzerland
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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; 51:4696-4708. [PMID: 38569052 DOI: 10.1002/mp.17043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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.
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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
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Wuensche TE, Lyashchenko S, van Dongen GAMS, Vugts D. Good practices for 89Zr radiopharmaceutical production and quality control. EJNMMI Radiopharm Chem 2024; 9:40. [PMID: 38733556 PMCID: PMC11088613 DOI: 10.1186/s41181-024-00258-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 03/21/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND During the previous two decades, PET imaging of biopharmaceuticals radiolabeled with zirconium-89 has become a consistent tool in preclinical and clinical drug development and patient selection, primarily due to its advantageous physical properties that allow straightforward radiolabeling of antibodies (89Zr-immuno-PET). The extended half-life of 78.4 h permits flexibility with respect to the logistics of tracer production, transportation, and imaging and allows imaging at later points in time. Additionally, its relatively low positron energy contributes to high-sensitivity, high-resolution PET imaging. Considering the growing interest in radiolabeling antibodies, antibody derivatives, and other compound classes with 89Zr in both clinical and pre-clinical settings, there is an urgent need to acquire valuable recommendations and guidelines towards standardization of labeling procedures. MAIN BODY This review provides an overview of the key aspects of 89Zr-radiochemistry and radiopharmaceuticals. Production of 89Zr, conjugation with the mostly used chelators and radiolabeling strategies, and quality control of the radiolabeled products are described in detail, together with discussions about alternative options and critical steps, as well as recommendations for troubleshooting. Moreover, some historical background on 89Zr-immuno-PET, coordination chemistry of 89Zr, and future perspectives are provided. This review aims to serve as a quick-start guide for scientists new to the field of 89Zr-immuno-PET and to suggest approaches for harmonization and standardization of current procedures. CONCLUSION The favorable PET imaging characteristics of 89Zr, its excellent availability due to relatively simple production and purification processes, and the development of suitable bifunctional chelators have led to the widespread use of 89Zr. The combination of antibodies and 89Zr, known as 89Zr-immuno-PET, has become a cornerstone in drug development and patient selection in recent years. Despite the advanced state of 89Zr-immuno-PET, new developments in chelator conjugation and radiolabeling procedures, application in novel compound classes, and improved PET scanner technology and quantification methods continue to reshape its landscape towards improving clinical outcomes.
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Affiliation(s)
- Thomas Erik Wuensche
- Department of Radiology & Nuclear Medicine, Amsterdam UMC Location Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
| | - Serge Lyashchenko
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, USA
| | - Guus A M S van Dongen
- Department of Radiology & Nuclear Medicine, Amsterdam UMC Location Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, The Netherlands
| | - Danielle Vugts
- Department of Radiology & Nuclear Medicine, Amsterdam UMC Location Vrije Universiteit Amsterdam, De Boelelaan 1117, Amsterdam, The Netherlands.
- Amsterdam Neuroscience, Brain Imaging, Amsterdam, The Netherlands.
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Yagishita A, Takeda S, Ohnuki K, Katsuragawa M, Sampetrean O, Fujii H, Takahashi T. Dual-radionuclide in vivo imaging of micro-metastasis and lymph tract with submillimetre resolution. Sci Rep 2023; 13:19464. [PMID: 37945679 PMCID: PMC10636167 DOI: 10.1038/s41598-023-46907-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/07/2023] [Indexed: 11/12/2023] Open
Abstract
Multi-radionuclide in vivo imaging with submillimetre resolution can be a potent tool for biomedical research. While high-resolution radionuclide imaging faces challenges in sensitivity, multi-radionuclide imaging encounters difficulty due to radiation contamination, stemming from crosstalk between radionuclides and Compton scattering. Addressing these challenges simultaneously is imperative for multi-radionuclide high-resolution imaging. To tackle this, we developed a high-spatial-resolution and high-energy-resolution small animal single-photon emission computed tomography (SPECT) scanner, named CdTe-DSD SPECT-I. We first assessed the feasibility of multi-tracer SPECT imaging of submillimetre targets. Using the CdTe-DSD SPECT-I, we performed SPECT imaging of submillimetre zeolite spheres absorbed with 125I- and subsequently imaged 125I-accumulated spheroids of 200-400 µm in size within an hour, achieving clear and quantitative images. Furthermore, dual-radionuclide phantom imaging revealed a distinct image of the submillimetre sphere absorbed with 125I- immersed in a 99mTc-pertechnetate solution, and provided a fair quantification of each radionuclide. Lastly, in vivo imaging was conducted on a cancer-bearing mouse with lymph node micro-metastasis using dual-tracers. The results displayed dual-tracer images of lymph tract by 99mTc-phytic acid and the submillimetre metastatic lesion by 125I-, shown to align with the immunofluorescence image.
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Affiliation(s)
- Atsushi Yagishita
- Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8583, Japan.
| | - Shin'ichiro Takeda
- Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8583, Japan
| | - Kazunobu Ohnuki
- Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, 277-8577, Japan
| | - Miho Katsuragawa
- Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8583, Japan
| | - Oltea Sampetrean
- Department of Molecular Biology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Human Biology-Microbiome-Quantum Research Center (WPI-Bio2Q), Keio University, 2-15-45 Mita, Minato, Tokyo, 108-8345, Japan
| | - Hirofumi Fujii
- Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, 6-5-1 Kashiwanoha, Kashiwa, 277-8577, Japan
| | - Tadayuki Takahashi
- Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI), The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8583, Japan
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033, Japan
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Pratt EC, Lopez-Montes A, Volpe A, Crowley MJ, Carter LM, Mittal V, Pillarsetty N, Ponomarev V, Udías JM, Grimm J, Herraiz JL. Simultaneous quantitative imaging of two PET radiotracers via the detection of positron-electron annihilation and prompt gamma emissions. Nat Biomed Eng 2023; 7:1028-1039. [PMID: 37400715 PMCID: PMC10810307 DOI: 10.1038/s41551-023-01060-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 05/23/2023] [Indexed: 07/05/2023]
Abstract
In conventional positron emission tomography (PET), only one radiotracer can be imaged at a time, because all PET isotopes produce the same two 511 keV annihilation photons. Here we describe an image reconstruction method for the simultaneous in vivo imaging of two PET tracers and thereby the independent quantification of two molecular signals. This method of multiplexed PET imaging leverages the 350-700 keV range to maximize the capture of 511 keV annihilation photons and prompt γ-ray emission in the same energy window, hence eliminating the need for energy discrimination during reconstruction or for signal separation beforehand. We used multiplexed PET to track, in mice with subcutaneous tumours, the biodistributions of intravenously injected [124I]I-trametinib and 2-deoxy-2-[18F]fluoro-D-glucose, [124I]I-trametinib and its nanoparticle carrier [89Zr]Zr-ferumoxytol, and the prostate-specific membrane antigen (PSMA) and infused PSMA-targeted chimaeric antigen receptor T cells after the systemic administration of [68Ga]Ga-PSMA-11 and [124I]I. Multiplexed PET provides more information depth, gives new uses to prompt γ-ray-emitting isotopes, reduces radiation burden by omitting the need for an additional computed-tomography scan and can be implemented on preclinical and clinical systems without any modifications in hardware or image acquisition software.
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Affiliation(s)
- Edwin C Pratt
- Department of Pharmacology, Weill Cornell Graduate School, New York, NY, USA
- Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Alejandro Lopez-Montes
- Nuclear Physics Group, EMFTEL and IPARCOS, Complutense University of Madrid, Madrid, Spain
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Alessia Volpe
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Michael J Crowley
- Department of Cell and Developmental Biology, Weill Cornell Graduate School, New York, NY, USA
| | - Lukas M Carter
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Vivek Mittal
- Department of Cell and Developmental Biology, Weill Cornell Graduate School, New York, NY, USA
- Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, USA
- Neuberger Berman Lung Cancer Center, Weill Cornell Medicine, New York, USA
- Sandra and Edward Meyer Cancer Center, Weill Cornell Medicine, New York, USA
| | | | - Vladimir Ponomarev
- Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Jose M Udías
- Nuclear Physics Group, EMFTEL and IPARCOS, Complutense University of Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Hospital Clínico San Carlos, Madrid, Spain
| | - Jan Grimm
- Department of Pharmacology, Weill Cornell Graduate School, New York, NY, USA.
- Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
- Department of Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
| | - Joaquin L Herraiz
- Nuclear Physics Group, EMFTEL and IPARCOS, Complutense University of Madrid, Madrid, Spain.
- Instituto de Investigación Sanitaria Hospital Clínico San Carlos, Madrid, Spain.
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Llosá G, Rafecas M. Hybrid PET/Compton-camera imaging: an imager for the next generation. EUROPEAN PHYSICAL JOURNAL PLUS 2023; 138:214. [PMID: 36911362 PMCID: PMC9990967 DOI: 10.1140/epjp/s13360-023-03805-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
Compton cameras can offer advantages over gamma cameras for some applications, since they are well suited for multitracer imaging and for imaging high-energy radiotracers, such as those employed in radionuclide therapy. While in conventional clinical settings state-of-the-art Compton cameras cannot compete with well-established methods such as PET and SPECT, there are specific scenarios in which they can constitute an advantageous alternative. The combination of PET and Compton imaging can benefit from the improved resolution and sensitivity of current PET technology and, at the same time, overcome PET limitations in the use of multiple radiotracers. Such a system can provide simultaneous assessment of different radiotracers under identical conditions and reduce errors associated with physical factors that can change between acquisitions. Advances are being made both in instrumentation developments combining PET and Compton cameras for multimodal or three-gamma imaging systems, and in image reconstruction, addressing the challenges imposed by the combination of the two modalities or the new techniques. This review article summarizes the advances made in Compton cameras for medical imaging and their combination with PET.
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Affiliation(s)
- Gabriela Llosá
- Instituto de Física Corpuscular (IFIC), CSIC-UV, Catedrático Beltrán, 2., 46980 Paterna, Valencia, Spain
| | - Magdalena Rafecas
- Institute of Medical Engineering (IMT), Universität zu Lübeck, Ratzeburger Allee 160, 23562 Lübeck, Germany
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Man F, Tang J, Swedrowska M, Forbes B, T M de Rosales R. Imaging drug delivery to the lungs: Methods and applications in oncology. Adv Drug Deliv Rev 2023; 192:114641. [PMID: 36509173 PMCID: PMC10227194 DOI: 10.1016/j.addr.2022.114641] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/14/2022]
Abstract
Direct delivery to the lung via inhalation is arguably one of the most logical approaches to treat lung cancer using drugs. However, despite significant efforts and investment in this area, this strategy has not progressed in clinical trials. Imaging drug delivery is a powerful tool to understand and develop novel drug delivery strategies. In this review we focus on imaging studies of drug delivery by the inhalation route, to provide a broad overview of the field to date and attempt to better understand the complexities of this route of administration and the significant barriers that it faces, as well as its advantages. We start with a discussion of the specific challenges for drug delivery to the lung via inhalation. We focus on the barriers that have prevented progress of this approach in oncology, as well as the most recent developments in this area. This is followed by a comprehensive overview of the different imaging modalities that are relevant to lung drug delivery, including nuclear imaging, X-ray imaging, magnetic resonance imaging, optical imaging and mass spectrometry imaging. For each of these modalities, examples from the literature where these techniques have been explored are provided. Finally the different applications of these technologies in oncology are discussed, focusing separately on small molecules and nanomedicines. We hope that this comprehensive review will be informative to the field and will guide the future preclinical and clinical development of this promising drug delivery strategy to maximise its therapeutic potential.
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Affiliation(s)
- Francis Man
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Jie Tang
- School of Biomedical Engineering & Imaging Sciences, King's College London, London SE1 7EH, United Kingdom
| | - Magda Swedrowska
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Ben Forbes
- School of Cancer & Pharmaceutical Sciences, King's College London, London, SE1 9NH, United Kingdom
| | - Rafael T M de Rosales
- School of Biomedical Engineering & Imaging Sciences, King's College London, London SE1 7EH, United Kingdom.
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Adler SS, Seidel J, Choyke PL. Advances in Preclinical PET. Semin Nucl Med 2022; 52:382-402. [PMID: 35307164 PMCID: PMC9038721 DOI: 10.1053/j.semnuclmed.2022.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 12/18/2022]
Abstract
The classical intent of PET imaging is to obtain the most accurate estimate of the amount of positron-emitting radiotracer in the smallest possible volume element located anywhere in the imaging subject at any time using the least amount of radioactivity. Reaching this goal, however, is confounded by an enormous array of interlinked technical issues that limit imaging system performance. As a result, advances in PET, human or animal, are the result of cumulative innovations across each of the component elements of PET, from data acquisition to image analysis. In the report that follows, we trace several of these advances across the imaging process with a focus on small animal PET.
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Affiliation(s)
- Stephen S Adler
- Frederick National Laboratory for Cancer Research, Frederick, MD; Molecular Imaging Branch, National Cancer Institute, Bethesda MD
| | - Jurgen Seidel
- Contractor to Frederick National Laboratory for Cancer Research, Leidos biodical Research, Inc., Frederick, MD; Molecular Imaging Branch, National Cancer Institute, Bethesda MD
| | - Peter L Choyke
- Molecular Imaging Branch, National Cancer Institute, Bethesda MD.
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Wilson CG, Aarons L, Augustijns P, Brouwers J, Darwich AS, De Waal T, Garbacz G, Hansmann S, Hoc D, Ivanova A, Koziolek M, Reppas C, Schick P, Vertzoni M, García-Horsman JA. Integration of advanced methods and models to study drug absorption and related processes: An UNGAP perspective. Eur J Pharm Sci 2021; 172:106100. [PMID: 34936937 DOI: 10.1016/j.ejps.2021.106100] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 01/09/2023]
Abstract
This collection of contributions from the European Network on Understanding Gastrointestinal Absorption-related Processes (UNGAP) community assembly aims to provide information on some of the current and newer methods employed to study the behaviour of medicines. It is the product of interactions in the immediate pre-Covid period when UNGAP members were able to meet and set up workshops and to discuss progress across the disciplines. UNGAP activities are divided into work packages that cover special treatment populations, absorption processes in different regions of the gut, the development of advanced formulations and the integration of food and pharmaceutical scientists in the food-drug interface. This involves both new and established technical approaches in which we have attempted to define best practice and highlight areas where further research is needed. Over the last months we have been able to reflect on some of the key innovative approaches which we were tasked with mapping, including theoretical, in silico, in vitro, in vivo and ex vivo, preclinical and clinical approaches. This is the product of some of us in a snapshot of where UNGAP has travelled and what aspects of innovative technologies are important. It is not a comprehensive review of all methods used in research to study drug dissolution and absorption, but provides an ample panorama of current and advanced methods generally and potentially useful in this area. This collection starts from a consideration of advances in a priori approaches: an understanding of the molecular properties of the compound to predict biological characteristics relevant to absorption. The next four sections discuss a major activity in the UNGAP initiative, the pursuit of more representative conditions to study lumenal dissolution of drug formulations developed independently by academic teams. They are important because they illustrate examples of in vitro simulation systems that have begun to provide a useful understanding of formulation behaviour in the upper GI tract for industry. The Leuven team highlights the importance of the physiology of the digestive tract, as they describe the relevance of gastric and intestinal fluids on the behaviour of drugs along the tract. This provides the introduction to microdosing as an early tool to study drug disposition. Microdosing in oncology is starting to use gamma-emitting tracers, which provides a link through SPECT to the next section on nuclear medicine. The last two papers link the modelling approaches used by the pharmaceutical industry, in silico to Pop-PK linking to Darwich and Aarons, who provide discussion on pharmacometric modelling, completing the loop of molecule to man.
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Affiliation(s)
- Clive G Wilson
- Strathclyde Institute of Pharmacy & Biomedical Sciences, Glasgow, U.K.
| | | | | | | | | | | | | | | | | | | | - Mirko Koziolek
- NCE Formulation Sciences, Abbvie Deutschland GmbH & Co. KG, Germany
| | | | - Philipp Schick
- Department of Biopharmaceutics and Pharmaceutical Technology, Center of Drug Absorption and Transport, University of Greifswald, Germany
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