1
|
Mulugeta PG, Chi AW, Anderson TM. Molecular Imaging and Therapy of Differentiated Thyroid Carcinoma in Adults. Cancer J 2024; 30:194-201. [PMID: 38753754 DOI: 10.1097/ppo.0000000000000713] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
ABSTRACT Differentiated thyroid carcinoma (DTC) has been increasing in incidence in the United States over the last several decades, although mortality rates have remained low. Radioactive iodine therapy (RAI-T) has been a mainstay of treatment for DTC since the 1940s. Imaging of DTC before and after RAI-T primarily focuses on molecular imaging of the sodium iodide symporter. The expanding understanding of the molecular profile of DTC has increased available treatment options. Incorporation of risk stratification to treatment approaches has led to deintensification of both surgical and nonsurgical treatments, leading to decreased morbidity without compromising disease control.
Collapse
Affiliation(s)
- Philipose Getachew Mulugeta
- From the Associate Professor of Clinical Radiology, Clinical Director, Division of Nuclear Medicine Imaging and Therapy, Hospital of the University of Pennsylvania, Department of Radiology, 3400 Spruce Street, 1 Silverstein
| | - Anthony W Chi
- Staff Pathologist, Subchief for Molecular Pathology, Head & Neck Pathology and Hematology, Mid-Atlantic Permanente Medical Group, Regional Laboratory, 611 Executive Blvd, Rockville, MD 20852; and
| | - Thomas Michael Anderson
- Assistant Professor, Director of Therapeutic Nuclear Medicine, Department of Radiology, UNM School of Medicine, MSC10 5530, 1 University of New Mexico, Albuquerque, NM 87131
| |
Collapse
|
2
|
Tomita Y, Ichikawa Y, Sakuma H. Shine-through artifact due to high-radioactivity bladder and bowel gas in 18F-FDG PET/CT: impact of time-of-flight algorithm and radioactivity concentration of urine in the bladder on the occurrence of the artifacts. Ann Nucl Med 2022; 36:736-745. [PMID: 35635608 DOI: 10.1007/s12149-022-01756-2] [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: 03/25/2022] [Accepted: 05/16/2022] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Shine-though artifact can appear as regions with falsely increased uptake in the immediate vicinity of large hot sources in 18F-FDG PET/CT. This artifact may adversely affect the assessment of tumor involvement in the regions adjacent to the bladder. The purpose of this study was to evaluate the prevalence of shine-through artifacts in clinical 18F-FDG PET/CT examinations and the factors that can influence their occurrence and extent. METHODS PET/CT images were acquired with Discovery PET/CT 690. One hundred six patients who underwent 18F-FDG PET/CT for clinical purposes were retrospectively reviewed. PET images were reconstructed using 3-dimensional ordered-subset expectation maximization with and without time-of-flight (TOF). The shine-through artifact was defined as an erroneous accumulation of 18F-FDG between the bladder and the air region in the intestine without attenuation correction (AC) errors. The maximum standardized uptake value (SUVmax) of the artifact was measured, and the effect of TOF on this artifact was evaluated. The SUVmax in the bladder was compared in patients with and without the artifacts. A phantom containing two spheres simulating bladder and rectal gas was imaged while changing the radioactivity of 18F-FDG solution in the bladder sphere. The relationship between the bladder sphere radioactivity and the SUVmax of the shine-through artifacts was evaluated. RESULTS The shine-through artifact was more frequently observed on PET images reconstructed without TOF (12/106, 11.3%) as compared to PET images with TOF (8/106, 7.5%, p = 0.046). The SUVmax of the shine-through artifacts was significantly decreased by TOF reconstruction compared to non-TOF reconstruction (4.7 ± 1.7 vs 7.6 ± 3.1, p = 0.0078). The mean SUVmax of urinary bladders in patients with the artifacts was significantly higher than those without the artifacts on non-TOF images (74.9 ± 61.1 vs 46.3 ± 35.2, p = 0.038). In the phantom study, the SUVmax of the shine-through artifact increased as the radioactivity in the bladder-simulating sphere increased. CONCLUSION Shine-through artifacts were observed in approximately 10% of clinical 18F-FDG PET/CT examinations. Their magnitude is significantly associated with the radioactivity in the bladder and can be reduced by employing TOF. Recognizing this artifact allows for a more accurate interpretation of 18F-FDG pelvic studies.
Collapse
Affiliation(s)
- Yoya Tomita
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| | - Yasutaka Ichikawa
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan.
| | - Hajime Sakuma
- Department of Radiology, Mie University Hospital, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan
| |
Collapse
|
3
|
Meng X, Liu H, Li H, Wang S, Sun H, Wang F, Ding J, He L, Chen X, Jin L, Dong Y, Zhu H, Yang Z. Evaluating the impact of different positron emitters on the performance of a clinical PET/MR system. Med Phys 2022; 49:2642-2651. [PMID: 35106784 DOI: 10.1002/mp.15513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/27/2021] [Accepted: 01/06/2022] [Indexed: 11/07/2022] Open
Abstract
PURPOSE The positron range and prompt gamma emission are distinctive with different positron emitters. The performance assessment of an integrated PET/MR scanner with these positron emitters is required for related applications, as the magnetic field interferes with the positron propagation. Such an assessment is to be performed on the United Imaging uPMR 790 integrated PET/MR system. METHODS The performance measurement methods were modified based on NEMA NU 2-2012, involving 18 F, 64 Cu, 68 Ga, 89 Zr, and 124 I as positron emitters. The NEMA IEC phantom was used for evaluations of image qualities. An agarose cap was wrapped around the point source for tissue-simulating spatial resolution measurement. The count rate performance was assessed with selected positron emitters. Images of a 3D-printed Derenzo phantom and representative patients were also acquired. RESULTS The image quality measurement showed that all five positron emitters were suitable for the PET/MR system studied. However, due to the magnetic field, the image of the point source showed an elongated comet-tail feature, which could be eliminated by a tissue-simulating cap. This effect is more obvious in 124 I and 68 Ga, due to their long positron ranges. The imaging ability with various positron emitters was further validated with the count rate assessment, the Derenzo phantom, and the clinical images. CONCLUSIONS Different positron emitters could be effectively imaged by the PET/MR system tested. The resolution measurement strategy proposed could be applied to measure PET spatial resolution in the magnetic field. This article is protected by copyright. All rights reserved.
Collapse
Affiliation(s)
- Xiangxi Meng
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| | - Hui Liu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China.,United Imaging Healthcare, Shanghai, China
| | - Hui Li
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China.,Department of Nuclear Medicine, Peking University Third Hospital, Beijing, China
| | - Shujing Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| | - Hongwei Sun
- Central Research Institute, United Imaging Healthcare, Beijing, China
| | - Feng Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| | - Jin Ding
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| | - Liuchun He
- United Imaging Healthcare, Shanghai, China
| | - Xin Chen
- United Imaging Healthcare, Shanghai, China
| | - Lujia Jin
- Institute of Medical Technology, Peking University Health Science Center, Peking University, Beijing, China
| | - Yun Dong
- United Imaging Healthcare, Shanghai, China
| | - Hua Zhu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| | - Zhi Yang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Key Laboratory for Research and Evaluation of Radiopharmaceuticals (National Medical Products Administration), Department of Nuclear Medicine, Beijing Cancer Hospital & Institute, Beijing, China
| |
Collapse
|
4
|
Barati S, Enferadi M, Sarkar S, Geramifar P. The effect of magnetic field strength on the positron range and projected annihilation artifact in integrated PET/MR systems: A GATE Monte Carlo study. Med Phys 2021; 48:7712-7724. [PMID: 34706098 DOI: 10.1002/mp.15313] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 09/19/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022] Open
Abstract
PURPOSE With improvements in positron emission tomography/magnetic resonance imaging (PET/MRI) over the last decade, there is a need to investigate the projected annihilation (shine-through) artifact and resolution impact for different PET radiopharmaceuticals, magnetic field (MF) strengths, and tissues. METHODS The GATE Monte Carlo (MC) simulation was used to simulate the annihilation distribution of positrons in different tissues and MFs. The positron distribution was studied in magnetic field (MF) intensities up to 15 T for 11 C, 13 N, 15 O, 18 F, 68 Ga, and 82 Rb. Moreover, the image quality in terms of the occurrence of projected annihilation artifacts was investigated using the 4D anthropomorphic digital extended cardiac-torso (XCAT) phantom. RESULTS Positron ranges were restricted across the directions perpendicular to the MF, but no change along the direction of the MF was detected. The projected annihilation artifacts were observed with the presence of MF in the sagittal and coronal view of PET images prepared from the XCAT phantom. The intensity of artifact was constant in MFs higher than 3 T. The significant effect of the MF on resolution improvement was observed in soft tissue for 68 Ga in 7 T and 82 Rb in 3 and 7 T, while higher MFs have no impact on resolution. The improvement of resolution in the lung tissue was observed for the medium- and high-energy radionuclides in 7 T MF. CONCLUSION The MF can create the projected annihilation artifact in the boundary of air cavities and other tissues for medium- and high-energy radionuclides especially for 68 Ga in clinical studies. In addition, the strength of the MFs more than 3 T was ineffective on the intensity of the projected annihilation artifact. In a clinical PET/MR scanner, MF has remarkable spatial resolution improvement in lung tissue, especially for medium- and high-energy radionuclides, and negligible effect in bone and soft tissue for most radionuclides.
Collapse
Affiliation(s)
- Sepideh Barati
- Department of Nuclear Medicine, Vali-Asr Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Milad Enferadi
- Division of Molecular Imaging and Theranostics, Department of Nuclear Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Saeed Sarkar
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran
| | - Parham Geramifar
- Research Center for Nuclear Medicine, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| |
Collapse
|
5
|
Zampella E, Klain M, Pace L, Cuocolo A. PET/CT in the management of differentiated thyroid cancer. Diagn Interv Imaging 2021; 102:515-523. [PMID: 33926848 DOI: 10.1016/j.diii.2021.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 04/07/2021] [Indexed: 12/17/2022]
Abstract
The standard treatment of differentiated thyroid cancer (DTC) consists of surgery followed by iodine-131 (131I) administration. Although the majority of DTC has a very good prognosis, more aggressive histologic subtypes convey a worse prognosis. Follow-up consists of periodically measurements of serum thyroglobulin, thyroglobulin antibodies and neck ultrasound and 123I/131I whole-body scan. However, undifferentiated thyroid tumors have a lower avidity for radioiodine and the ability of DTC to concentrate 131I may be lost in metastatic disease. Positron emission tomography (PET)/computed tomography (CT) has been introduced in the evaluation of patients with thyroid tumors and the 2-[18F]-fluoro-2-deoxyd-glucose (18F-FDG) has been largely validated as marker of cell's metabolism. According to the 2015 American Thyroid Association guidelines, 18F-FDG PET/CT is recommended in the follow-up of high-risk patients with elevated serum thyroglobulin and negative 131I imaging, in the assessment of metastatic patients, for lesion detection and risk stratification and in predicting the response to therapy. It should be considered that well-differentiated iodine avid lesions could not concentrate 18F-FDG, and a reciprocal pattern of iodine and 18F-FDG uptake has been observed. Beyond 18F-FDG, other tracers are available for PET imaging of thyroid tumors, such as Iodine-124 (124I), 18F-tetrafluoroborate and Gallium-68 prostate-specific membrane antigen. Moreover, the recent introduction of PET/MRI, offers now several opportunities in the field of patients with DTC. This review summarizes the evidences on the role of PET/CT in management of patients with DTC, focusing on potential applications and on elucidating some still debating points.
Collapse
Affiliation(s)
- Emilia Zampella
- Department of Advanced Biomedical Sciences, University Federico II, 80131 Naples, Italy.
| | - Michele Klain
- Department of Advanced Biomedical Sciences, University Federico II, 80131 Naples, Italy
| | - Leonardo Pace
- Department of Medicine, Surgery and Dentistry, Università degli Studi di Salerno, 84084 Fisciano, Italy
| | - Alberto Cuocolo
- Department of Advanced Biomedical Sciences, University Federico II, 80131 Naples, Italy
| |
Collapse
|
6
|
Herraiz JL, Bembibre A, López-Montes A. Deep-Learning Based Positron Range Correction of PET Images. APPLIED SCIENCES-BASEL 2020. [DOI: https://doi.org/10.3390/app11010266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Positron emission tomography (PET) is a molecular imaging technique that provides a 3D image of functional processes in the body in vivo. Some of the radionuclides proposed for PET imaging emit high-energy positrons, which travel some distance before they annihilate (positron range), creating significant blurring in the reconstructed images. Their large positron range compromises the achievable spatial resolution of the system, which is more significant when using high-resolution scanners designed for the imaging of small animals. In this work, we trained a deep neural network named Deep-PRC to correct PET images for positron range effects. Deep-PRC was trained with modeled cases using a realistic Monte Carlo simulation tool that considers the positron energy distribution and the materials and tissues it propagates into. Quantification of the reconstructed PET images corrected with Deep-PRC showed that it was able to restore the images by up to 95% without any significant noise increase. The proposed method, which is accessible via Github, can provide an accurate positron range correction in a few seconds for a typical PET acquisition.
Collapse
|
7
|
Abstract
Positron emission tomography (PET) is a molecular imaging technique that provides a 3D image of functional processes in the body in vivo. Some of the radionuclides proposed for PET imaging emit high-energy positrons, which travel some distance before they annihilate (positron range), creating significant blurring in the reconstructed images. Their large positron range compromises the achievable spatial resolution of the system, which is more significant when using high-resolution scanners designed for the imaging of small animals. In this work, we trained a deep neural network named Deep-PRC to correct PET images for positron range effects. Deep-PRC was trained with modeled cases using a realistic Monte Carlo simulation tool that considers the positron energy distribution and the materials and tissues it propagates into. Quantification of the reconstructed PET images corrected with Deep-PRC showed that it was able to restore the images by up to 95% without any significant noise increase. The proposed method, which is accessible via Github, can provide an accurate positron range correction in a few seconds for a typical PET acquisition.
Collapse
|
8
|
Weber M, Binse I, Nagarajah J, Bockisch A, Herrmann K, Jentzen W. The role of 124I PET/CT lesion dosimetry in differentiated thyroid cancer. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF RADIOPHARMACEUTICAL CHEMISTRY AND BIOLOGY 2019; 63:235-252. [DOI: 10.23736/s1824-4785.19.03201-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
9
|
Cal-Gonzalez J, Vaquero JJ, Herraiz JL, Pérez-Liva M, Soto-Montenegro ML, Peña-Zalbidea S, Desco M, Udías JM. Improving PET Quantification of Small Animal [ 68Ga]DOTA-Labeled PET/CT Studies by Using a CT-Based Positron Range Correction. Mol Imaging Biol 2018; 20:584-593. [PMID: 29352372 DOI: 10.1007/s11307-018-1161-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE Image quality of positron emission tomography (PET) tracers that emits high-energy positrons, such as Ga-68, Rb-82, or I-124, is significantly affected by positron range (PR) effects. PR effects are especially important in small animal PET studies, since they can limit spatial resolution and quantitative accuracy of the images. Since generators accessibility has made Ga-68 tracers wide available, the aim of this study is to show how the quantitative results of [68Ga]DOTA-labeled PET/X-ray computed tomography (CT) imaging of neuroendocrine tumors in mice can be improved using positron range correction (PRC). PROCEDURES Eighteen scans in 12 mice were evaluated, with three different models of tumors: PC12, AR42J, and meningiomas. In addition, three different [68Ga]DOTA-labeled radiotracers were used to evaluate the PRC with different tracer distributions: [68Ga]DOTANOC, [68Ga]DOTATOC, and [68Ga]DOTATATE. Two PRC methods were evaluated: a tissue-dependent (TD-PRC) and a tissue-dependent spatially-variant correction (TDSV-PRC). Taking a region in the liver as reference, the tissue-to-liver ratio values for tumor tissue (TLRtumor), lung (TLRlung), and necrotic areas within the tumors (TLRnecrotic) and their respective relative variations (ΔTLR) were evaluated. RESULTS All TLR values in the PRC images were significantly different (p < 0.05) than the ones from non-PRC images. The relative differences of the tumor TLR values, respect to the case with no PRC, were ΔTLRtumor 87 ± 41 % (TD-PRC) and 85 ± 46 % (TDSV-PRC). TLRlung decreased when applying PRC, being this effect more remarkable for the TDSV-PRC method, with relative differences respect to no PRC: ΔTLRlung = - 45 ± 24 (TD-PRC), - 55 ± 18 (TDSV-PRC). TLRnecrotic values also decreased when using PRC, with more noticeable differences for TD-PRC: ΔTLRnecrotic = - 52 ± 6 (TD-PRC), - 48 ± 8 (TDSV-PRC). CONCLUSION The PRC methods proposed provide a significant quantitative improvement in [68Ga]DOTA-labeled PET/CT imaging of mice with neuroendocrine tumors, hence demonstrating that these techniques could also ameliorate the deleterious effect of the positron range in clinical PET imaging.
Collapse
Affiliation(s)
- Jacobo Cal-Gonzalez
- QIMP group, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain.
| | - Juan José Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
| | - Joaquín L Herraiz
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - Mailyn Pérez-Liva
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | | | - Santiago Peña-Zalbidea
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- IRAB-Institut de Radiofarmàcia Aplicada de Barcelona (PRBB), Barcelona, Spain
| | - Manuel Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
- CIBERSAM, Madrid, Spain
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - José Manuel Udías
- Grupo de Física Nuclear, Dpto. Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| |
Collapse
|
10
|
Mannheim JG, Schmid AM, Schwenck J, Katiyar P, Herfert K, Pichler BJ, Disselhorst JA. PET/MRI Hybrid Systems. Semin Nucl Med 2018; 48:332-347. [PMID: 29852943 DOI: 10.1053/j.semnuclmed.2018.02.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the last decade, the combination of PET and MRI in one system has proven to be highly successful in basic preclinical research, as well as in clinical research. Nowadays, PET/MRI systems are well established in preclinical imaging and are progressing into clinical applications to provide further insights into specific diseases, therapeutic assessments, and biological pathways. Certain challenges in terms of hardware had to be resolved concurrently with the development of new techniques to be able to reach the full potential of both combined techniques. This review provides an overview of these challenges and describes the opportunities that simultaneous PET/MRI systems can exploit in comparison with stand-alone or other combined hybrid systems. New approaches were developed for simultaneous PET/MRI systems to correct for attenuation of 511 keV photons because MRI does not provide direct information on gamma photon attenuation properties. Furthermore, new algorithms to correct for motion were developed, because MRI can accurately detect motion with high temporal resolution. The additional information gained by the MRI can be employed to correct for partial volume effects as well. The development of new detector designs in combination with fast-decaying scintillator crystal materials enabled time-of-flight detection and incorporation in the reconstruction algorithms. Furthermore, this review lists the currently commercially available systems both for preclinical and clinical imaging and provides an overview of applications in both fields. In this regard, special emphasis has been placed on data analysis and the potential for both modalities to evolve with advanced image analysis tools, such as cluster analysis and machine learning.
Collapse
Affiliation(s)
- Julia G Mannheim
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Andreas M Schmid
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Johannes Schwenck
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany; Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Prateek Katiyar
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Kristina Herfert
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany.
| | - Jonathan A Disselhorst
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| |
Collapse
|
11
|
Cal-Gonzalez J, Vaquero JJ, Herraiz JL, Pérez-Liva M, Soto-Montenegro ML, Peña-Zalbidea S, Desco M, Udías JM. Improving PET Quantification of Small Animal [68Ga]DOTA-Labeled PET/CT Studies by Using a CT-Based Positron Range Correction. Mol Imaging Biol 2018. [DOI: https://doi.org/10.1007/s11307-018-1161-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
12
|
Conti M, Eriksson L. Physics of pure and non-pure positron emitters for PET: a review and a discussion. EJNMMI Phys 2016; 3:8. [PMID: 27271304 PMCID: PMC4894854 DOI: 10.1186/s40658-016-0144-5] [Citation(s) in RCA: 202] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/31/2015] [Indexed: 01/09/2023] Open
Abstract
With the increased interest in new PET tracers, gene-targeted therapy, immunoPET, and theranostics, other radioisotopes will be increasingly used in clinical PET scanners, in addition to 18F. Some of the most interesting radioisotopes with prospective use in the new fields are not pure short-range β+ emitters but can be associated with gamma emissions in coincidence with the annihilation radiation (prompt gamma), gamma-gamma cascades, intense Bremsstrahlung radiation, high-energy positrons that may escape out of the patient skin, and high-energy gamma rays that result in some e+/e− pair production. The high level of sophistication in data correction and excellent quantitative accuracy that has been reached for 18F in recent years can be questioned by these effects. In this work, we review the physics and the scientific literature and evaluate the effect of these additional phenomena on the PET data for each of a series of radioisotopes: 11C, 13N, 15O, 18F, 64Cu, 68Ga, 76Br, 82Rb, 86Y, 89Zr, 90Y, and 124I. In particular, we discuss the present complications arising from the prompt gammas, and we review the scientific literature on prompt gamma correction. For some of the radioisotopes considered in this work, prompt gamma correction is definitely needed to assure acceptable image quality, and several approaches have been proposed in recent years. Bremsstrahlung photons and 176Lu background were also evaluated.
Collapse
Affiliation(s)
- Maurizio Conti
- Siemens Healthcare Molecular Imaging, Knoxville, TN, USA.
| | - Lars Eriksson
- Siemens Healthcare Molecular Imaging, Knoxville, TN, USA.,Department of Physics, University of Stockholm, Stockholm, Sweden.,Karolinska Institute, Stockholm, Sweden.,Scintillation Material Research Center, University of Tennessee, Knoxville, TN, USA
| |
Collapse
|
13
|
Cal-González J, Pérez-Liva M, Herraiz JL, Vaquero JJ, Desco M, Udías JM. Tissue-Dependent and Spatially-Variant Positron Range Correction in 3D PET. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:2394-403. [PMID: 26011878 DOI: 10.1109/tmi.2015.2436711] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Positron range (PR) is a significant factor that limits PET image resolution, especially with some radionuclides currently used in clinical and preclinical studies such as (82)Rb, (124)I and (68)Ga. The use of an accurate model of the PR in the image reconstruction may minimize its impact on the image quality. Nevertheless, PR distributions are difficult to model, as they may be different at each voxel and direction, depending on the materials that the positron flies through. Several approximated methods have been proposed, considering only one or several propagating media without taking into account boundaries effects. In some regions, like lungs or trachea, these methods may not be accurate enough and yield artifacts. In this work, we present an efficient method to accurately incorporate spatially-variant PR corrections. The method is based on pre-computing voxel-dependent PR kernels using a CT or a manually segmented image, and a model of the dependence of the PR on each material derived from Monte Carlo simulations. The images are convoluted with these kernels in the forward-projection step of the iterative reconstruction algorithm. This implementation of the algorithm adds a modest overhead to the overall reconstruction time and it obtains artifact-free PR-corrected images, even when the activity is concentrated at tissue boundaries with extreme changes of density. We verified the method with the preclinical Argus PET/CT scanner, but it can be also applied to other scanners and improve the image quality in clinical PET studies using isotopes with large PR.
Collapse
|
14
|
Kolb A, Sauter AW, Eriksson L, Vandenbrouke A, Liu CC, Levin C, Pichler BJ, Rafecas M. Shine-Through in PET/MR Imaging: Effects of the Magnetic Field on Positron Range and Subsequent Image Artifacts. J Nucl Med 2015; 56:951-4. [DOI: 10.2967/jnumed.114.147637] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 01/19/2015] [Indexed: 11/16/2022] Open
|
15
|
|
16
|
Ament SJ, Maus S, Reber H, Buchholz HG, Bausbacher N, Brochhausen C, Graf F, Miederer M, Schreckenberger M. PET lung ventilation/perfusion imaging using (68)Ga aerosol (Galligas) and (68)Ga-labeled macroaggregated albumin. Recent Results Cancer Res 2013; 194:395-423. [PMID: 22918772 DOI: 10.1007/978-3-642-27994-2_22] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Pulmonary imaging using ventilation/perfusion (V/P) single-photon emission tomography (V/P scan) with Tc-99m-labeled radiotracers is a well-established diagnostic tool for clinically suspected pulmonary embolism (PE). Ga-68 aerosol (Galligas) and Ga-68-labeled macroaggregated albumin (MAA) are potential tracers for positron emission tomography (PET) lung V/P imaging and could display an advantage over conventional V/P scans in terms of sensitivity and specificity. After radiochemical and animal studies, the clinical applicability of Ga-68 aerosol (Galligas) and Ga-68-labeled MAA was investigated in an exploratory study in patients with clinical suspicion of PE. PET scans were acquired using a 16-slice Gemini TF positron emission tomography/computed tomography (PET/CT) scanner. The acquisition protocol included low-dose computed tomography (CT) for attenuation correction (AC). Dosimetry calculations and continuative phantom measurements were performed. Structural analyses showed no modification of the particles due to the labeling process. In addition, in vitro experiments showed stability of Ga-68 MAA in various media. As expected, Ga-68-labeled human serum albumin microspheres (HSAM) were completely retained in the lung of the animals. In clinical use, PET lung ventilation and perfusion imaging using Ga-68 aerosol (Galligas) and Ga-68-labeled MAA was successful in all cases. In one case a clinically suspected PE could be detected and verified. The administered activity of Ga-68 aerosol (Galligas) and Ga-68-labeled MAA may be reduced by more than 50%, resulting in comparable radiation exposure to conventional V/P scans. In conclusion, Ga-68 aerosol (Galligas) and Ga-68-labeled MAA are efficient substitutes for clinical use and could be an interesting alternative with high accuracy for lung V/P imaging with Tc-99m-labeled radiotracers, especially in times of Mo-99 shortages and increasing use and spread of PET/CT scanners and Ga-68 generators, respectively.
Collapse
Affiliation(s)
- S J Ament
- Department of Nuclear Medicine, University Medical Centre, Johannes Gutenberg-University, Mainz, Germany.
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Freudenberg LS, Jentzen W, Stahl A, Bockisch A, Rosenbaum-Krumme SJ. Clinical applications of 124I-PET/CT in patients with differentiated thyroid cancer. Eur J Nucl Med Mol Imaging 2011; 38 Suppl 1:S48-56. [DOI: 10.1007/s00259-011-1773-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 02/22/2011] [Indexed: 11/30/2022]
|
18
|
Van Nostrand D, Moreau S, Bandaru VV, Atkins F, Chennupati S, Mete M, Burman K, Wartofsky L. (124)I positron emission tomography versus (131)I planar imaging in the identification of residual thyroid tissue and/or metastasis in patients who have well-differentiated thyroid cancer. Thyroid 2010; 20:879-83. [PMID: 20615132 DOI: 10.1089/thy.2009.0430] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND AND OBJECTIVE (124)I emits a positron and can be imaged with a positron emission tomography (PET) scanner. The objective of this study was to compare the ability of diagnostic (124)I PET images versus (131)I planar whole-body imaging in detecting residual thyroid tissue and/or metastatic well-differentiated thyroid cancer (WDTC). METHODS Patients were recruited prospectively for this study who (i) had WDTC, (ii) were suspected of having metastatic WDTC, and (iii) were referred for (131)I whole-body dosimetry. The prescribed activity was 1-2 mCi (37-74 MBq) and 1.7 mCi (62.9 MBq) for (131)I and (124)I, respectively. For each image, one blinded reader (D.V.N.) categorized every focus of (131)I and (124)I radioiodine uptake as 1 = definite physiological uptake/artifact, 2 = most likely physiological uptake/artifact, 3 = indeterminate, 4 = residual thyroid tissue/metastases in the neck/bed, 5 = most likely metastases, or 6 = definite metastases. Foci categorized as 4, 5, or 6 were considered positive. When available, foci categorized as 4, 5, or 6 were correlated with other diagnostic studies. RESULTS Of the 25 patients, 8 patients (32%) had more positive foci on (124)I images than on (131)I, of which 3 patients to date have had metastases confirmed in one or more of the additional positive (124)I foci. (124)I demonstrated the same number of foci as on (131)I in 16 patients (14 with no positive foci, and 2 with two positive and five positive foci each). One patient had one additional positive focus on (131)I not seen on (124)I, which has not yet been confirmed as a metastasis. A total of 97 positive foci were identified on either (124)I or (131)I. (124)I identified 49 positive foci not seen with (131)I, and (131)I identified one positive focus not seen with (124)I. CONCLUSION Relative to (131)I planar whole-body imaging, (124)I PET identified as many as 50% more foci of radioiodine uptake suggestive of additional residual thyroid tissue and/or metastases in as many as 32% more patients who had WDTC.
Collapse
Affiliation(s)
- Douglas Van Nostrand
- Division of Nuclear Medicine, Washington Hospital Center , Washington, DC 20010, USA.
| | | | | | | | | | | | | | | |
Collapse
|