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Sitarz M, Cussonneau JP, Matulewicz T, Haddad F. Radionuclide candidates for β+γ coincidence PET: An overview. Appl Radiat Isot 2020; 155:108898. [DOI: 10.1016/j.apradiso.2019.108898] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 09/11/2019] [Accepted: 09/19/2019] [Indexed: 12/20/2022]
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Impact of prompt gamma coincidence correction on absorbed dose estimation in differentiated thyroid cancer using 124I PET/CT imaging. Nucl Med Commun 2018; 39:1156-1164. [PMID: 30204643 DOI: 10.1097/mnm.0000000000000911] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Iodine-124 positron emission tomography/computed tomography (I PET/CT) is increasingly being used in the absorbed dose estimation in the radioiodine treatment of differentiated thyroid cancer (DTC). However, the produced prompt gamma coincidences (PGCs) associated with the I decay result in a bias in the absorbed dose estimation. The impact of a sinogram-based PGC correction approach on the absorbed dose estimation in I PET/CT DTC imaging is investigated. METHODS I phantom and patient measurements were performed on a Siemens Biograph mCT PET/CT system. All images were reconstructed with (PGCon) and without PGC correction (PGCoff). The phantom contained seven spheres (diameters: 6.6-37 mm). The spheres and background compartment were filled with a I solution, resulting in a low (9.4 : 1) and a high sphere-to-background activity concentration ratio (750 : 1). Sphere recovery coefficient (RC) values were determined. In addition, the impact of PGC correction on measured lesion uptake and calculated lesion-absorbed dose was assessed for 66 lesions identified in 24 DTC patients. RESULTS PGC correction systematically increased sphere RC values up to 71% for the smallest spheres. For the patient data, PGC correction significantly increased both the measured I uptake (P<0.005) and the calculated lesion-absorbed dose (P=0.008) by ∼3%. The percentage difference in the calculated lesion-absorbed dose ranged from -19% to 50%, showing that PGC correction had a variable and large impact for a few lesions. CONCLUSION PGC correction resulted in significantly higher sphere RC values, I lesion uptake values and estimated lesion-absorbed doses.
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Robinson AP, Tipping J, Cullen DM, Hamilton D, Brown R, Flynn A, Oldfield C, Page E, Price E, Smith A, Snee R. Organ-specific SPECT activity calibration using 3D printed phantoms for molecular radiotherapy dosimetry. EJNMMI Phys 2016; 3:12. [PMID: 27411356 PMCID: PMC4943909 DOI: 10.1186/s40658-016-0148-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 06/28/2016] [Indexed: 01/09/2023] Open
Abstract
Background Patient-specific absorbed dose calculations for molecular radiotherapy require accurate activity quantification. This is commonly derived from Single-Photon Emission Computed Tomography (SPECT) imaging using a calibration factor relating detected counts to known activity in a phantom insert. Methods A series of phantom inserts, based on the mathematical models underlying many clinical dosimetry calculations, have been produced using 3D printing techniques. SPECT/CT data for the phantom inserts has been used to calculate new organ-specific calibration factors for 99mTc and 177Lu. The measured calibration factors are compared to predicted values from calculations using a Gaussian kernel. Results Measured SPECT calibration factors for 3D printed organs display a clear dependence on organ shape for 99mTc and 177Lu. The observed variation in calibration factor is reproduced using Gaussian kernel-based calculation over two orders of magnitude change in insert volume for 99mTc and 177Lu. These new organ-specific calibration factors show a 24, 11 and 8 % reduction in absorbed dose for the liver, spleen and kidneys, respectively. Conclusions Non-spherical calibration factors from 3D printed phantom inserts can significantly improve the accuracy of whole organ activity quantification for molecular radiotherapy, providing a crucial step towards individualised activity quantification and patient-specific dosimetry. 3D printed inserts are found to provide a cost effective and efficient way for clinical centres to access more realistic phantom data.
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Affiliation(s)
- Andrew P Robinson
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.
| | - Jill Tipping
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester, M20 4BX, UK
| | - David M Cullen
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - David Hamilton
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester, M20 4BX, UK
| | - Richard Brown
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Alex Flynn
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Christopher Oldfield
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Emma Page
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK.,Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester, M20 4BX, UK
| | - Emlyn Price
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Andrew Smith
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
| | - Richard Snee
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester, M13 9PL, UK
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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.
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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
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Soderlund AT, Chaal J, Tjio G, Totman JJ, Conti M, Townsend DW. Beyond 18F-FDG: Characterization of PET/CT and PET/MR Scanners for a Comprehensive Set of Positron Emitters of Growing Application--18F, 11C, 89Zr, 124I, 68Ga, and 90Y. J Nucl Med 2015; 56:1285-91. [PMID: 26135111 DOI: 10.2967/jnumed.115.156711] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/23/2015] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED This study aimed to investigate image quality for a comprehensive set of isotopes ((18)F, (11)C, (89)Zr, (124)I, (68)Ga, and (90)Y) on 2 clinical scanners: a PET/CT scanner and a PET/MR scanner. METHODS Image quality and spatial resolution were tested according to NU 2-2007 of the National Electrical Manufacturers Association. An image-quality phantom was used to measure contrast recovery, residual bias in a cold area, and background variability. Reconstruction methods available on the 2 scanners were compared, including point-spread-function correction for both scanners and time of flight for the PET/CT scanner. Spatial resolution was measured using point sources and filtered backprojection reconstruction. RESULTS With the exception of (90)Y, small differences were seen in the hot-sphere contrast recovery of the different isotopes. Cold-sphere contrast recovery was similar across isotopes for all reconstructions, with an improvement seen with time of flight on the PET/CT scanner. The lower-statistic (90)Y scans yielded substantially lower contrast recovery than the other isotopes. When isotopes were compared, there was no difference in measured spatial resolution except for PET/MR axial spatial resolution, which was significantly higher for (124)I and (68)Ga. CONCLUSION Overall, both scanners produced good images with (18)F, (11)C, (89)Zr, (124)I, (68)Ga, and (90)Y.
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Affiliation(s)
| | - Jasper Chaal
- A*STAR-NUS Clinical Imaging Research Center, Singapore
| | - Gabriel Tjio
- A*STAR-NUS Clinical Imaging Research Center, Singapore
| | - John J Totman
- A*STAR-NUS Clinical Imaging Research Center, Singapore
| | - Maurizio Conti
- Siemens Healthcare Molecular Imaging, Knoxville, Tennessee; and
| | - David W Townsend
- A*STAR-NUS Clinical Imaging Research Center, Singapore Department of Diagnostic Radiology, National University Hospital, Singapore
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Koehler L, Gagnon K, McQuarrie S, Wuest F. Iodine-124: a promising positron emitter for organic PET chemistry. Molecules 2010; 15:2686-718. [PMID: 20428073 PMCID: PMC6257279 DOI: 10.3390/molecules15042686] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/07/2010] [Accepted: 04/09/2010] [Indexed: 11/16/2022] Open
Abstract
The use of radiopharmaceuticals for molecular imaging of biochemical and physiological processes in vivo has evolved into an important diagnostic tool in modern nuclear medicine and medical research. Positron emission tomography (PET) is currently the most sophisticated molecular imaging methodology, mainly due to the unrivalled high sensitivity which allows for the studying of biochemistry in vivo on the molecular level. The most frequently used radionuclides for PET have relatively short half-lives (e.g. 11C: 20.4 min; 18F: 109.8 min) which may limit both the synthesis procedures and the time frame of PET studies. Iodine-124 (124I, t1/2 = 4.2 d) is an alternative long-lived PET radionuclide attracting increasing interest for long term clinical and small animal PET studies. The present review gives a survey on the use of 124I as promising PET radionuclide for molecular imaging. The first part describes the production of 124I. The second part covers basic radiochemistry with 124I focused on the synthesis of 124I-labeled compounds for molecular imaging purposes. The review concludes with a summary and an outlook on the future prospective of using the long-lived positron emitter 124I in the field of organic PET chemistry and molecular imaging.
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Affiliation(s)
- Lena Koehler
- Institute of Radiopharmacy, Research Center Dresden-Rossendorf, Dresden, Germany; E-Mail: (L.K.)
| | - Katherine Gagnon
- Department of Physics, University of Alberta, Edmonton, Canada; E-Mail: (K.G.)
| | - Steve McQuarrie
- Department of Oncology, University of Alberta, Edmonton, Canada; E-Mail: (S.M.)
| | - Frank Wuest
- Department of Oncology, University of Alberta, Edmonton, Canada; E-Mail: (S.M.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1 780 989 8150; Fax: +1 780 432 8483
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