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Hammersen N, Jentzen W, Stawitzki F, Herrmann K, Kersting D, Fragoso Costa P, Moraitis A. PET quantification performance of the oversize-volume-of-interest approach in the context of tumour dosimetry in radionuclide therapy planning. Phys Med Biol 2024; 69:165007. [PMID: 38925139 DOI: 10.1088/1361-6560/ad5c36] [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: 03/10/2024] [Accepted: 06/26/2024] [Indexed: 06/28/2024]
Abstract
Objective.The partial-volume effect (PVE) is an important factor impairing tumour quantification in molecular imaging. The commonly used contour-volume-of-interest (contour-VOI) approach to correct for this effect employs phantom-based recovery coefficients. Applying oversize-VOIs could offer superior quantification accuracy in small lesions. The oversize-VOI approach uses a large oversize volume to determine the total tumour activity after applying a background correction. Aims of this study were to provide a procedure for the application of the oversize-VOI approach and to compare its performance to the contour-VOI approach in PET imaging.Approach.A sphere tumour model was simulated to determine the oversize diameter that contained 90%, 95%, and 98% of the total activity as a function of the tumour size. Experimental investigations involving phantom and clinical data were conducted on a digital PET/CT scanner. In the phantom investigation, 12 spherical tumour inserts (diameters ranging from 3.7 to 37.4 mm) containing18F-solution were used. The accuracy of the contour- and oversize-VOI approach was evaluated for different signal-to-background ratios (20-3). Clinically, both approaches were applied on PET/CT images acquired with18F-labelled prostate-specific membrane antigen in prostate cancer patients.Main results.From the tumour model, we deduced that an oversize-VOI of two PET spatial resolutions larger than the physical lesion diameter contains at least 98% of the total activity for lesions with diameters down to one PET spatial resolution, while minimizing the background contribution. Both approaches were robust against varying phantom and clinical imaging conditions. Performance of the oversize-VOI approach was favorable for lesions below 10 mm in diameter, whereas the contour-VOI approach was slightly more accurate for sizes above 10 mm.Significance.The oversize-VOI approach facilitates image quantification of small tumours. It is simple and effective to correct for the PVE and may be used in pre-therapeutic (small) tumour dosimetry.
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Affiliation(s)
- Noah Hammersen
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Walter Jentzen
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Florian Stawitzki
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Ken Herrmann
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - David Kersting
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Pedro Fragoso Costa
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
| | - Alexandros Moraitis
- Department of Nuclear Medicine, West German Cancer Center (WTZ), University Hospital Essen, University of Duisburg-Essen, Essen, Germany
- German Cancer Consortium (DKTK), Partner Site University Hospital Essen, Essen, Germany
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Hellwig D, Hellwig NC, Boehner S, Fuchs T, Fischer R, Schmidt D. Artificial Intelligence and Deep Learning for Advancing PET Image Reconstruction: State-of-the-Art and Future Directions. Nuklearmedizin 2023; 62:334-342. [PMID: 37995706 PMCID: PMC10689088 DOI: 10.1055/a-2198-0358] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/12/2023] [Indexed: 11/25/2023]
Abstract
Positron emission tomography (PET) is vital for diagnosing diseases and monitoring treatments. Conventional image reconstruction (IR) techniques like filtered backprojection and iterative algorithms are powerful but face limitations. PET IR can be seen as an image-to-image translation. Artificial intelligence (AI) and deep learning (DL) using multilayer neural networks enable a new approach to this computer vision task. This review aims to provide mutual understanding for nuclear medicine professionals and AI researchers. We outline fundamentals of PET imaging as well as state-of-the-art in AI-based PET IR with its typical algorithms and DL architectures. Advances improve resolution and contrast recovery, reduce noise, and remove artifacts via inferred attenuation and scatter correction, sinogram inpainting, denoising, and super-resolution refinement. Kernel-priors support list-mode reconstruction, motion correction, and parametric imaging. Hybrid approaches combine AI with conventional IR. Challenges of AI-assisted PET IR include availability of training data, cross-scanner compatibility, and the risk of hallucinated lesions. The need for rigorous evaluations, including quantitative phantom validation and visual comparison of diagnostic accuracy against conventional IR, is highlighted along with regulatory issues. First approved AI-based applications are clinically available, and its impact is foreseeable. Emerging trends, such as the integration of multimodal imaging and the use of data from previous imaging visits, highlight future potentials. Continued collaborative research promises significant improvements in image quality, quantitative accuracy, and diagnostic performance, ultimately leading to the integration of AI-based IR into routine PET imaging protocols.
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Affiliation(s)
- Dirk Hellwig
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
- Partner Site Regensburg, Bavarian Center for Cancer Research (BZKF), Regensburg, Germany
- Medical Data Integration Center (MEDIZUKR), University Hospital Regensburg, Regensburg, Germany
| | - Nils Constantin Hellwig
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
- Medical Data Integration Center (MEDIZUKR), University Hospital Regensburg, Regensburg, Germany
| | - Steven Boehner
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
- Partner Site Regensburg, Bavarian Center for Cancer Research (BZKF), Regensburg, Germany
- Medical Data Integration Center (MEDIZUKR), University Hospital Regensburg, Regensburg, Germany
| | - Timo Fuchs
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
- Partner Site Regensburg, Bavarian Center for Cancer Research (BZKF), Regensburg, Germany
- Medical Data Integration Center (MEDIZUKR), University Hospital Regensburg, Regensburg, Germany
| | - Regina Fischer
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
- Partner Site Regensburg, Bavarian Center for Cancer Research (BZKF), Regensburg, Germany
- Medical Data Integration Center (MEDIZUKR), University Hospital Regensburg, Regensburg, Germany
| | - Daniel Schmidt
- Department of Nuclear Medicine, University Hospital Regensburg, Regensburg, Germany
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Shirakawa Y, Matsutomo N. Impact of list-mode reconstruction and image-space point spread function correction on PET image contrast and quantitative value using SiPM-based PET/CT system. Radiol Phys Technol 2023; 16:384-396. [PMID: 37368168 DOI: 10.1007/s12194-023-00729-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
We evaluate the effects of list-mode reconstruction and the image-space point spread function (iPSF) on the contrast and quantitative values of positron emission tomography (PET) images using a SiPM-PET/CT system. The evaluation is conducted on an NEMA body phantom and clinical images using a Cartesion Prime SiPM-PET/CT system. The signal-to-background ratio (SBR) of the phantom is set to 2, 4, 6, and 8, and all the PET image data are obtained and reconstructed using 3D-OSEM, time-of-flight, iPSF (-/ +), and a 4-mm Gaussian filter with several iterations. The evaluation criteria include % background variability (NB,10 mm), % contrast (QH,10 mm), iPSF change in QH,10 mm (ΔQH,10 mm) for edge artifact evaluation, profile curves, visual evaluation of edge artifacts, clinical imaging for the standardized uptake value (SUV) of lung nodules, and SNRliver. NB,10 mm demonstrates no significant difference in all SBRs with and without iPSF, whereas QH,10 mm is higher based on the SBR with and without iPSF. ΔQH,10 mm indicates increased iterations and a larger rate of change (> 5%) for small spheres of < 17 mm. The profile curves portrayed almost real concentrations, except for the 10-mm sphere of SBR2 without iPSF; however, with iPSF, an overshoot was observed in the 13-mm sphere of all SBRs. The degree of overshoot increased with increasing iteration and SBR. Edge artifacts were detected at values ≥ 17-22 mm in SBRs other than SBR2 with iPSF. Irrespective of the nodal size, SUV and SNRliver improved considerably after iPSF adjustment. Therefore, the effects of list-mode reconstruction and iPSF on PET image contrast were limited, and the overcorrection of the quantitative values was validated using iPSF.
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Affiliation(s)
- Yuya Shirakawa
- Department of Radiology, Kyorin University Hospital, 6-20-2 Shinkawa, Mitaka, Tokyo, 181-8611, Japan.
| | - Norikazu Matsutomo
- Department of Medical Radiological Technology, Faculty of Health Sciences, Kyorin University, Mitaka, Tokyo, 181-8612, Japan
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Kamikawa Y, Yoshida Y, Kawahara Y. Effects of point spread function correction and time-of-flight on visual contrast level and pixel values in brain PET images. Nucl Med Commun 2023; 44:442-456. [PMID: 36897055 DOI: 10.1097/mnm.0000000000001681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
OBJECTIVES Point spread function (PSF) correction and time-of-flight (TOF) can improve the quality of PET images. None have directly assessed the visual effects of these methods in brain PET images and evaluated the image quality from these methods based on the relationship between the number of updates and noise level. The present study aimed to clarify the effects of PSF and TOF on the visual contrast level and pixel values of brain PET images using an experimental phantom. MATERIALS AND METHODS The visual contrast level was evaluated based on the sum of edge strengths. In addition, the effects of PSF, TOF, and a combination of them on pixel values were evaluated after anatomical standardization of brain images, in which the whole brain was divided into 18 segments. These were evaluated using images reconstructed with the number of updates set to achieve the same noise level. RESULTS Combined application of the point spread function and TOF resulted in the greatest increase in the sum of edge strengths (32%), followed by PSF (21%) and TOF (6%). The maximum increase in pixel values occurred in the thalamic area (17%). CONCLUSION Although PSF and TOF can increase the visual contrast level by increasing the sum of edge strengths, they may affect the results of software-based analysis using pixel values. Nonetheless, using these methods may improve the ability to visualize areas of hypoaccumulation, such as epileptic foci.
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Affiliation(s)
- Yohei Kamikawa
- Department of Radiology, Oita University Hospital, Yufu, Oita
| | - Yukito Yoshida
- Department of Radiology, Oita University Hospital, Yufu, Oita
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Cheng X, Yang D, Saha D, Sun X, Shao Y. Integrated Small Animal PET/CT/RT with Onboard PET/CT Image Guidance for Preclinical Radiation Oncology Research. Tomography 2023; 9:567-578. [PMID: 36961005 PMCID: PMC10037572 DOI: 10.3390/tomography9020046] [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: 02/02/2023] [Revised: 02/22/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
We have integrated a compact and lightweight PET with an existing CT image-guided small animal irradiator to enable practical onboard PET/CT image-guided preclinical radiation therapy (RT) research. The PET with a stationary and full-ring detectors has ~1.1 mm uniform spatial resolution over its imaging field-of-view of 8.0 cm diameter and 3.5 cm axial length and was mechanically installed inside the irradiator in a tandem configuration with CT and radiation unit. A common animal bed was used for acquiring sequential dual functional and anatomical images with independent PET and CT control and acquisition systems. The reconstructed dual images were co-registered based on standard multi-modality image calibration and registration processes. Phantom studies were conducted to evaluate the integrated system and dual imaging performance. The measured mean PET/CT image registration error was ~0.3 mm. With one-bed and three-bed acquisitions, initial tumor focused and whole-body [18F]FDG animal images were acquired to test the capability of onboard PET/CT image guidance for preclinical RT research. Overall, the results have shown that integrated PET/CT/RT can provide advantageous and practical onboard PET/CT image to significantly enhance the accuracy of tumor delineation and radiation targeting that should enhance the existing and enable new and potentially breakthrough preclinical RT research and applications.
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Affiliation(s)
- Xinyi Cheng
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Dongxu Yang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Debabrata Saha
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xiankai Sun
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Yiping Shao
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Korsholm K, Overbeck N, Dias AH, Loft A, Andersen FL, Fischer BM. Impact of Reduced Image Noise on Deauville Scores in Patients with Lymphoma Scanned on a Long-Axial Field-of-View PET/CT-Scanner. Diagnostics (Basel) 2023; 13:diagnostics13050947. [PMID: 36900090 PMCID: PMC10000539 DOI: 10.3390/diagnostics13050947] [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: 02/04/2023] [Revised: 02/24/2023] [Accepted: 02/25/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Total body and long-axial field-of-view (LAFOV) PET/CT represent visionary innovations in imaging enabling either improved image quality, reduction in injected activity-dose or decreased acquisition time. An improved image quality may affect visual scoring systems, including the Deauville score (DS), which is used for clinical assessment of patients with lymphoma. The DS compares SUVmax in residual lymphomas with liver parenchyma, and here we investigate the impact of reduced image noise on the DS in patients with lymphomas scanned on a LAFOV PET/CT. METHODS Sixty-eight patients with lymphoma underwent a whole-body scan on a Biograph Vision Quadra PET/CT-scanner, and images were evaluated visually with regard to DS for three different timeframes of 90, 300, and 600 s. SUVmax and SUVmean were calculated from liver and mediastinal blood pool, in addition to SUVmax from residual lymphomas and measures of noise. RESULTS SUVmax in liver and in mediastinal blood pool decreased significantly with increasing acquisition time, whereas SUVmean remained stable. In residual tumor, SUVmax was stable during different acquisition times. As a result, the DS was subject to change in three patients. CONCLUSIONS Attention should be drawn towards the eventual impact of improvements in image quality on visual scoring systems such as the DS.
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Affiliation(s)
- Kirsten Korsholm
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
- Correspondence:
| | - Nanna Overbeck
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
| | - André H. Dias
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Annika Loft
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
| | - Flemming Littrup Andersen
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Barbara Malene Fischer
- Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, 2100 Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
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Braune A, Oehme L, Freudenberg R, Hofheinz F, van den Hoff J, Kotzerke J, Hoberück S. Comparison of image quality and spatial resolution between 18F, 68Ga, and 64Cu phantom measurements using a digital Biograph Vision PET/CT. EJNMMI Phys 2022; 9:58. [PMID: 36064989 PMCID: PMC9445107 DOI: 10.1186/s40658-022-00487-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 08/22/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND PET nuclides can have a considerable influence on the spatial resolution and image quality of PET/CT scans, which can influence diagnostics in oncology, for example. The individual impact of the positron energy of 18F, 68Ga, and 64Cu on spatial resolution and image quality was compared for PET/CT scans acquired using a clinical, digital scanner. METHODS A Jaszczak phantom and a NEMA PET body phantom were filled with 18F-FDG, 68Ga-HCl, or 64Cu-HCl, and PET/CT scans were performed on a Siemens Biograph Vision. Acquired images were analyzed regarding spatial resolution and image quality (recovery coefficients (RC), coefficient of variation within the background, contrast recovery coefficient (CRC), contrast-noise ratio (CNR), and relative count error in the lung insert). Data were compared between scans with different nuclides. RESULTS We found that image quality was comparable between 18F-FDG and 64Cu-HCl PET/CT measurements featuring similar maximal endpoint energies of the positrons. In comparison, RC, CRC, and CNR were degraded in 68Ga-HCl data despite similar count rates. In particular, the two smallest spheres of 10 mm and 13 mm diameter revealed lower RC, CRC, and CNR values. The spatial resolution was similar between 18F-FDG and 64Cu-HCl but up to 18% and 23% worse compared with PET/CT images of the NEMA PET body phantom filled with 68Ga-HCl. CONCLUSIONS The positron energy of the PET nuclide influences the spatial resolution and image quality of a digital PET/CT scan. The image quality and spatial resolution of 68Ga-HCl PET/CT images were worse than those of 18F-FDG or 64Cu-HCl despite similar count rates.
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Affiliation(s)
- Anja Braune
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany.
| | - Liane Oehme
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Robert Freudenberg
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Frank Hofheinz
- PET Center, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Jörg van den Hoff
- PET Center, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
| | - Jörg Kotzerke
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany.,PET Center, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany.,Department of Nuclear Medicine, Medizinische Fakultat Carl Gustav Carus, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Sebastian Hoberück
- Department of Nuclear Medicine, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany.,Department of Nuclear Medicine, Helios Klinikum Erfurt, Erfurt, Germany
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Rausch I, Beitzke D, Li X, Pfaff S, Rasul S, Haug AR, Mayerhoefer ME, Hacker M, Beyer T, Cal-González J. Accuracy of PET quantification in [ 68Ga]Ga-pentixafor PET/MR imaging of carotid plaques. J Nucl Cardiol 2022; 29:492-502. [PMID: 32696137 PMCID: PMC8993720 DOI: 10.1007/s12350-020-02257-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/15/2020] [Indexed: 12/29/2022]
Abstract
AIM The aim of this study was to evaluate and correct for partial-volume-effects (PVE) on [68Ga]Ga-Pentixafor uptake in atherosclerotic plaques of the carotid arteries, and the impact of ignoring bone in MR-based attenuation correction (MR-AC). METHODS Twenty [68Ga]Ga-pentixafor PET/MR examinations including a high-resolution T2-TSE MR of the neck were included in this study. Carotid plaques located at the carotid bifurcation were delineated and the anatomical information was used for partial-volume-correction (PVC). Mean and max tissue-to-background ratios (TBR) of the [68Ga]Ga-Pentixafor uptake were compared for standard and PVC-PET images. A potential influence of ignoring bone in MR-AC was assessed in a subset of the data reconstructed after incorporating bone into MR-AC and a subsequent comparison of standardized-uptake values (SUV). RESULTS In total, 34 atherosclerotic plaques were identified. Following PVC, mean and max TBR increased by 77 and 95%, respectively, when averaged across lesions. When accounting for bone in the MR-AC, SUV of plaque changed by 0.5%. CONCLUSION Quantitative readings of [68Ga]Ga-pentixafor uptake in plaques are strongly affected by PVE, which can be reduced by PVC. Including bone information into the MR-AC yielded no clinically relevant effect on tracer quantification.
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Affiliation(s)
- Ivo Rausch
- QIMP Team, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Dietrich Beitzke
- Division of Cardiovascular and Interventional Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Xiang Li
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Sahra Pfaff
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Sazan Rasul
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Alexander R Haug
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
- Christian Doppler Lab for Applied Metabolomics, Medical University of Vienna, Vienna, Austria
| | - Marius E Mayerhoefer
- Division of General and Pediatric Radiology, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Beyer
- QIMP Team, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Jacobo Cal-González
- QIMP Team, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Rogasch JMM, Hofheinz F, van Heek L, Voltin CA, Boellaard R, Kobe C. Influences on PET Quantification and Interpretation. Diagnostics (Basel) 2022; 12:451. [PMID: 35204542 PMCID: PMC8871060 DOI: 10.3390/diagnostics12020451] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/06/2022] [Accepted: 02/08/2022] [Indexed: 01/21/2023] Open
Abstract
Various factors have been identified that influence quantitative accuracy and image interpretation in positron emission tomography (PET). Through the continuous introduction of new PET technology-both imaging hardware and reconstruction software-into clinical care, we now find ourselves in a transition period in which traditional and new technologies coexist. The effects on the clinical value of PET imaging and its interpretation in routine clinical practice require careful reevaluation. In this review, we provide a comprehensive summary of important factors influencing quantification and interpretation with a focus on recent developments in PET technology. Finally, we discuss the relationship between quantitative accuracy and subjective image interpretation.
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Affiliation(s)
- Julian M. M. Rogasch
- Department of Nuclear Medicine, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany;
- Berlin Institute of Health at Charité, Universitätsmedizin Berlin, 10178 Berlin, Germany
| | - Frank Hofheinz
- Institute of Radiopharmaceutical Cancer Research, Helmholtz Center Dresden-Rossendorf, 01328 Dresden, Germany;
| | - Lutz van Heek
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.v.H.); (C.-A.V.)
| | - Conrad-Amadeus Voltin
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.v.H.); (C.-A.V.)
| | - Ronald Boellaard
- Department of Radiology and Nuclear Medicine, Cancer Center Amsterdam (CCA), Amsterdam University Medical Center, Free University Amsterdam, 1081 HV Amsterdam, The Netherlands;
| | - Carsten Kobe
- Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50937 Cologne, Germany; (L.v.H.); (C.-A.V.)
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Compensating Positron Range Effects of Ga-68 in Preclinical PET Imaging by Using Convolutional Neural Network: A Monte Carlo Simulation Study. Diagnostics (Basel) 2021; 11:diagnostics11122275. [PMID: 34943511 PMCID: PMC8700176 DOI: 10.3390/diagnostics11122275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/11/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
This study aimed to investigate the feasibility of positron range correction based on three different convolutional neural network (CNN) models in preclinical PET imaging of Ga-68. The first model (CNN1) was originally designed for super-resolution recovery, while the second model (CNN2) and the third model (CNN3) were originally designed for pseudo CT synthesis from MRI. A preclinical PET scanner and 30 phantom configurations were modeled in Monte Carlo simulations, where each phantom configuration was simulated twice, once for Ga-68 (CNN input images) and once for back-to-back 511-keV gamma rays (CNN output images) with a 20 min emission scan duration. The Euclidean distance was used as the loss function to minimize the difference between CNN input and output images. According to our results, CNN3 outperformed CNN1 and CNN2 qualitatively and quantitatively. With regard to qualitative observation, it was found that boundaries in Ga-68 images became sharper after correction. As for quantitative analysis, the recovery coefficient (RC) and spill-over ratio (SOR) were increased after correction, while no substantial increase in coefficient of variation of RC (CVRC) or coefficient of variation of SOR (CVSOR) was observed. Overall, CNN3 should be a good candidate architecture for positron range correction in Ga-68 preclinical PET imaging.
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Huang K, Feng Y, Liang W, Li L. Impact of time of flight and point spread function on quantitative parameters of lung lesions in 18F-FDG PET/CT. BMC Med Imaging 2021; 21:169. [PMID: 34773998 PMCID: PMC8590319 DOI: 10.1186/s12880-021-00699-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 10/26/2021] [Indexed: 11/23/2022] Open
Abstract
Background Image reconstruction algorithm is one of the important factors affecting the quantitative parameters of PET/CT. The purpose of this study was to investigate the effects of time of flight (TOF) and point spread function (PSF) on quantitative parameters of lung lesions in 18F-FDG PET/CT. Methods This retrospective study evaluated 60 lung lesions in 39 patients who had undergone 18F-fluoro-deoxy-glucose (FDG) PET/CT. All lesions larger than 10 mm in diameter were included in the study. The PET data were reconstructed with a baseline ordered-subsets expectation–maximization (OSEM) algorithm, OSEM + PSF, OSEM + TOF and OSEM + TOF + PSF respectively. The differences of maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), metabolic tumor volume (MTV), total lesion glycolysis (TLG)and signal to noise ratio (SNR)were compared among different reconstruction algorithms. Results Compared with OSEM reconstruction, using OSEM + TOF + PSF increased SUVmean and SUVmax by 23.73% and 22.71% respectively, and SNR increased by 70.18%, MTV decreased by 23.84% (p < 0.01). The percentage difference was significantly higher in smaller lesions (diameter 10–22 mm) than in larger lesions (diameter 23–44 mm), and significantly higher in low contrast lesions (SNR ≤ 15.31) than in high contrast lesions (SNR > 15.31). The difference of TLG among various reconstruction algorithms is relatively small, the highest value is − 6.48% of OSEM + TOF + PSF, and the lowest value is 0.81% of OSEM + TOF. Conclusion TOF and PSF significantly affected the quantitative parameters of lung lesions in 18F-FDG PET/CT. OSEM + TOF + PSF can significantly increased SUVmax, SUVmean and SNR, and significantly reduce MTV, especially in small lesions and low contrast lesions. TLG can be relatively stable in different reconstruction algorithms.
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Affiliation(s)
- Kemin Huang
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, 528000, Guangdong, China.
| | - Yanlin Feng
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, 528000, Guangdong, China
| | - Weitang Liang
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, 528000, Guangdong, China
| | - Lin Li
- Department of Nuclear Medicine, The First People's Hospital of Foshan, Foshan, 528000, Guangdong, China
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12
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Rogasch JMM, Boellaard R, Pike L, Borchmann P, Johnson P, Wolf J, Barrington SF, Kobe C. Moving the goalposts while scoring-the dilemma posed by new PET technologies. Eur J Nucl Med Mol Imaging 2021; 48:2696-2710. [PMID: 33990846 PMCID: PMC8263433 DOI: 10.1007/s00259-021-05403-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023]
Affiliation(s)
- Julian M M Rogasch
- Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Ronald Boellaard
- Radiology and Nuclear Medicine, Cancer Centre Amsterdam, Amsterdam UMC, De Boelelaan 1117, Amsterdam, The Netherlands
| | - Lucy Pike
- King's College London and Guy's and St Thomas' PET Centre, School of Biomedical Engineering and Imaging Sciences, King's College London, King's Health Partners, London, UK
| | - Peter Borchmann
- German Hodgkin Study Group, Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, University of Cologne, Cologne, Germany
| | - Peter Johnson
- Cancer Research UK Centre, University of Southampton, Southampton, UK
| | - Jürgen Wolf
- Department I of Internal Medicine, Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf, University Hospital Cologne and University of Cologne, Cologne, Germany
| | - Sally F Barrington
- King's College London and Guy's and St Thomas' PET Centre, School of Biomedical Engineering and Imaging Sciences, King's College London, King's Health Partners, London, UK
| | - Carsten Kobe
- Department of Nuclear Medicine, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany.
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13
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Rogasch JMM, Frost N, Bluemel S, Michaels L, Penzkofer T, von Laffert M, Temmesfeld-Wollbrück B, Neudecker J, Rückert JC, Ochsenreither S, Böhmer D, Amthauer H, Furth C. FDG-PET/CT for pretherapeutic lymph node staging in non-small cell lung cancer: A tailored approach to the ESTS/ESMO guideline workflow. Lung Cancer 2021; 157:66-74. [PMID: 33994197 DOI: 10.1016/j.lungcan.2021.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 04/23/2021] [Accepted: 05/01/2021] [Indexed: 12/25/2022]
Abstract
OBJECTIVES In patients with NSCLC, current ESTS and ESMO guidelines recommend invasive lymph node (LN) staging with EBUS-TBNA even if FDG-PET/CT is negative for mediastinal LNs if at least one of three risk factors is present (cN1, non-peripheral primary or primary >3 cm). Modified workflows to avoid unnecessary invasive procedures were evaluated. MATERIALS AND METHODS Monocentric retrospective analysis of pretherapeutic FDG-PET/CT in 247 patients with NSCLC (62 % male; age, 68 [43-88] years) using an analog or digital PET/CT scanner. PET windowing was standardized. LNs were positive if 'LN uptake > mediastinal blood pool' or short axis >10 mm. Surgery or EBUS-TBNA served as reference for diagnostic accuracy per LN station. In all patients with negative mediastinal LNs by PET/CT, LN histology from surgery was available. RESULTS Among 700 L N stations analyzed, 180 were malignant. Sensitivity and specificity of PET/CT per LN station were 93 % and 71 %. Following current guidelines, 76 patients with mediastinal negative PET/CT required confirmatory invasive staging. Only 5/76 patients had unexpected pN2 (all had adenocarcinoma). In a modified approach, confirmatory invasive staging was confined to patients with mediastinal negative PET/CT who showed all three risk factors. Using this modification, EBUS-TBNA could have been omitted in 62 (82 %) of the 76 patients who required EBUS-TBNA based on current recommendation. Among these 62 patients, only one patient had unsuspected pN2 (single-level) while the remaining 61 of 62 omitted EBUS-TBNA were deemed unnecessary because mediastinal LNs were confirmed to be negative. No multi-level pN2 would have been missed. CONCLUSION In the current analysis, 82 % of EBUS-TBNA procedures in patients with mediastinal negative PET/CT could have been omitted by modifying the current guideline workflow as proposed (i.e., restricting EBUS-TBNA in patients with cN0/1 to those with all three risk factors). This was consistent with different PET/CT scanners. Prospective confirmation is required.
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Affiliation(s)
- Julian M M Rogasch
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Str. 2, 10178 Berlin, Germany.
| | - Nikolaj Frost
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Stephanie Bluemel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Liza Michaels
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Radiology, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Tobias Penzkofer
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Str. 2, 10178 Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Radiology, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Maximilian von Laffert
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pathology, Charitéplatz 1, 10117 Berlin, Germany.
| | - Bettina Temmesfeld-Wollbrück
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Infectious Diseases and Pulmonary Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Jens Neudecker
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of General, Visceral, Vascular and Thoracic Surgery, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Jens-Carsten Rückert
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of General, Visceral, Vascular and Thoracic Surgery, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Sebastian Ochsenreither
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Hematology and Medical Oncology, Hindenburgdamm 30, 12203 Berlin, Germany; Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charité Comprehensive Cancer Center, Charitéplatz 1, 10115 Berlin, Germany.
| | - Dirk Böhmer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Radiation Oncology, Hindenburgdamm 30, 12203 Berlin, Germany.
| | - Holger Amthauer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
| | - Christian Furth
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, 13353 Berlin, Germany.
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Mitamura K, Norikane T, Yamamoto Y, Fujimoto K, Takami Y, Hoshikawa H, Toyohara J, Nishiyama Y. Interim 4'-[methyl- 11C]-thiothymidine PET for predicting the chemoradiotherapeutic response in head and neck squamous cell carcinoma: comparison with [ 18F]FDG PET. EJNMMI Res 2021; 11:13. [PMID: 33566186 PMCID: PMC7876213 DOI: 10.1186/s13550-021-00749-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 01/05/2021] [Indexed: 11/28/2022] Open
Abstract
Purpose We investigated the potential of interim 4′-[methyl-11C]thiothymidine ([11C]4DST) PET for predicting the chemoradiotherapeutic response for head and neck squamous cell carcinoma (HNSCC), in comparison with 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) PET. Methods A total of 32 patients with HNSCC who underwent both [11C]4DST and [18F]FDG PET/CT before therapy (baseline) and at approximately 40 Gy point during chemoradiotherapy (interim) were available for a retrospective analysis of prospectively collected data. The baseline was treatment-naïve PET/CT scan as part of staging. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV) from [18F]FDG PET or proliferative tumor volume (PTV) from [11C]4DST PET, and total lesion glycolysis (TLG) from [18F]FDG PET or total lesion proliferation (TLP) from [11C]4DST PET were measured. MTV or PTV was defined as the volume with an SUVmax greater than 2.5. The differences in SUVmax (ΔSUVmax), MTV (ΔMTV) or PTV (ΔPTV) and TLG (ΔTLG) or TLP (ΔTLP) from baseline to interim PET scans were calculated. Patients without or with evidence of residual or recurrent disease at 3 months after completion of chemoradiotherapy were classified as showing a complete response (CR) and non-CR, respectively. Results All patients showed increased uptake in primary tumor on baseline [11C]4DST and [18F]FDG PET studies. All patients showed increased uptake on interim [18F]FDG PET, whereas 18 patients showed no increased uptake on interim [11C]4DST PET. After chemoradiotherapy, 25 patients were found to be in CR group and 7 to be in non-CR group. [11C]4DST ΔSUVmax, ΔPTV, and ΔTLP for CR group showed significantly greater reductions than the corresponding values for non-CR group (P = 0.044, < 0.001, < 0.001, respectively). However, there were no significant differences in [18F]FDG ΔSUVmax, ΔMTV, or ΔTLG between CR group and non-CR group. [11C]4DST ΔMTV of -90 was the best cutoff value for the early identification of patients with non-CR. Conclusion These preliminary results suggest that interim [11C]4DST PET might be useful for predicting the chemoradiotherapeutic response in patients with HNSCC, in comparison with [18F]FDG PET.
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Affiliation(s)
- Katsuya Mitamura
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Takashi Norikane
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Yuka Yamamoto
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan.
| | - Kengo Fujimoto
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Yasukage Takami
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
| | - Hiroshi Hoshikawa
- Department of Otolaryngology, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Jun Toyohara
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Yoshihiro Nishiyama
- Department of Radiology, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa, 761-0793, Japan
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15
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Detection of sub-centimeter lesions using digital TOF-PET/CT system combined with Bayesian penalized likelihood reconstruction algorithm. Ann Nucl Med 2020; 34:762-771. [DOI: 10.1007/s12149-020-01500-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/01/2020] [Indexed: 12/19/2022]
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Akerele MI, Karakatsanis NA, Deidda D, Cal-Gonzalez J, Forsythe RO, Dweck MR, Syed M, Newby DE, Aykroyd RG, Sourbron S, Tsoumpas C. Comparison of Correction Techniques for the Spill in Effect in Emission Tomography. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020; 4:422-432. [PMID: 33542967 DOI: 10.1109/trpms.2020.2980443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In positron emission tomography (PET) imaging, accurate clinical assessment is often affected by the partial volume effect (PVE) leading to overestimation (spill-in) or underestimation (spill-out) of activity in various small regions. The spill-in correction, in particular, can be very challenging when the target region is close to a hot background region. Therefore, this study evaluates and compares the performance of various recently developed spill-in correction techniques, namely: background correction (BC), local projection (LP), and hybrid kernelized (HKEM) methods. We used a simulated digital phantom and [18F]-NaF PET data of three patients with abdominal aortic aneurysms (AAA) acquired with Siemens Biograph mMR™ and mCT™ scanners respectively. Region of Interest (ROI) analysis was performed and the extracted SUV mean , SUV max and target-to-background ratio (TBR) scores were compared. Results showed substantial spill-in effects from hot regions to targeted regions, which are more prominent in small structures. The phantom experiment demonstrated the feasibility of spill-in correction with all methods. For the patient data, large differences in SUV mean , SUV max and TBR max scores were observed between the ROIs drawn over the entire aneurysm and ROIs excluding some regions close to the bone. Overall, BC yielded the best performance in spill-in correction in both phantom and patient studies.
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Affiliation(s)
- Mercy I Akerele
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Department of Radiology, Weil Cornell Medical College of Cornell University, NY, USA
| | - Nicolas A Karakatsanis
- Department of Radiology, Weil Cornell Medical College of Cornell University, NY, USA; Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, NY
| | - Daniel Deidda
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Department of Statistics, University of Leeds, UK; Nuclear Medicine Imaging, Medical Radiation Physics, National Physical Laboratory, London, UK
| | | | | | | | | | | | | | - Steven Sourbron
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK
| | - Charalampos Tsoumpas
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, NY
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Rogasch JM, Suleiman S, Hofheinz F, Bluemel S, Lukas M, Amthauer H, Furth C. Reconstructed spatial resolution and contrast recovery with Bayesian penalized likelihood reconstruction (Q.Clear) for FDG-PET compared to time-of-flight (TOF) with point spread function (PSF). EJNMMI Phys 2020; 7:2. [PMID: 31925574 PMCID: PMC6954158 DOI: 10.1186/s40658-020-0270-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 01/02/2020] [Indexed: 02/06/2023] Open
Abstract
Background Bayesian penalized likelihood reconstruction for PET (e.g., GE Q.Clear) aims at improving convergence of lesion activity while ensuring sufficient signal-to-noise ratio (SNR). This study evaluated reconstructed spatial resolution, maximum/peak contrast recovery (CRmax/CRpeak) and SNR of Q.Clear compared to time-of-flight (TOF) OSEM with and without point spread function (PSF) modeling. Methods The NEMA IEC Body phantom was scanned five times (3 min scan duration, 30 min between scans, background, 1.5–3.9 kBq/ml F18) with a GE Discovery MI PET/CT (3-ring detector) with spheres filled with 8-, 4-, or 2-fold the background activity concentration (SBR 8:1, 4:1, 2:1). Reconstruction included Q.Clear (beta, 150/300/450), “PSF+TOF4/16” (iterations, 4; subsets, 16; in-plane filter, 2.0 mm), “OSEM+TOF4/16” (identical parameters), “PSF+TOF2/17” (2 it, 17 ss, 2.0 mm filter), “OSEM+TOF2/17” (identical), “PSF+TOF4/8” (4 it, 8 ss, 6.4 mm), and “OSEM+TOF2/8” (2 it, 8 ss, 6.4 mm). Spatial resolution was derived from 3D sphere activity profiles. RC as (sphere activity concentration [AC]/true AC). SNR as (background mean AC/background AC standard deviation). Results Spatial resolution of Q.Clear150 was significantly better than all conventional algorithms at SBR 8:1 and 4:1 (Wilcoxon, each p < 0.05). At SBR 4:1 and 2:1, the spatial resolution of Q.Clear300/450 was similar or inferior to PSF+TOF4/16 and OSEM+TOF4/16. Small sphere CRpeak generally underestimated true AC, and it was similar for Q.Clear150/300/450 as with PSF+TOF4/16 or PSF+TOF2/17 (i.e., relative differences < 10%). Q.Clear provided similar or higher CRpeak as OSEM+TOF4/16 and OSEM+TOF2/17 resulting in a consistently better tradeoff between CRpeak and SNR with Q.Clear. Compared to PSF+TOF4/8/OSEM+TOF2/8, Q.Clear150/300/450 showed lower SNR but higher CRpeak. Conclusions Q.Clear consistently improved reconstructed spatial resolution at high and medium SBR compared to PSF+TOF and OSEM+TOF, but only with beta = 150. However, this is at the cost of inferior SNR with Q.Clear150 compared to Q.Clear300/450 and PSF+TOF4/16/PSF+TOF2/17 while CRpeak for the small spheres did not improve considerably. This suggests that Q.Clear300/450 may be advantageous for the 3-ring detector configuration because the tradeoff between CR and SNR with Q.Clear300/450 was superior to PSF+TOF4/16, OSEM+TOF4/16, and OSEM+TOF2/17. However, it requires validation by systematic evaluation in patients at different activity and acquisition protocols.
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Affiliation(s)
- Julian M Rogasch
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany.
| | - Said Suleiman
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany
| | - Frank Hofheinz
- Helmholtz-Zentrum Dresden-Rossendorf, Institute for Radiopharmaceutical Cancer Research, Dresden, Germany
| | - Stephanie Bluemel
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany
| | - Mathias Lukas
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany
| | - Holger Amthauer
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany
| | - Christian Furth
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nuclear Medicine, Augustenburger Platz 1, Berlin, Germany
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18
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Rezaei S, Ghafarian P, Bakhshayesh-Karam M, Uribe CF, Rahmim A, Sarkar S, Ay MR. The impact of iterative reconstruction protocol, signal-to-background ratio and background activity on measurement of PET spatial resolution. Jpn J Radiol 2020; 38:231-239. [PMID: 31894449 DOI: 10.1007/s11604-019-00914-3] [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: 09/25/2019] [Accepted: 12/19/2019] [Indexed: 02/04/2023]
Abstract
OBJECTIVES The present study aims to assess the impact of acquisition time, different iterative reconstruction protocols as well as image context (including contrast levels and background activities) on the measured spatial resolution in PET images. METHODS Discovery 690 PET/CT scanner was used to quantify spatial resolutions in terms of full width half maximum (FWHM) as derived (i) directly from capillary tubes embedded in air and (ii) indirectly from 10 mm-diameter sphere of the NEMA phantom. Different signal-to-background ratios (SBRs), background activity levels and acquisition times were applied. The emission data were reconstructed using iterative reconstruction protocols. Various combinations of iterations and subsets (it × sub) were evaluated. RESULTS For capillary tubes, improved FWHM values were obtained for higher it × sub, with improved performance for PSF algorithms relative to non-PSF algorithms. For the NEMA phantom, by increasing acquisition times from 1 to 5 min, intrinsic FWHM for reconstructions with it × sub 32 (54) was improved by 15.3% (13.2%), 15.1% (13.8%), 14.5% (12.8%) and 13.7% (12.7%) for OSEM, OSEM + PSF, OSEM + TOF and OSEM + PSF + TOF, respectively. Furthermore, for all reconstruction protocols, the FWHM improved with more impact for higher it × sub. CONCLUSION Our results indicate that PET spatial resolution is greatly affected by SBR, background activity and the choice of the reconstruction protocols.
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Affiliation(s)
- Sahar Rezaei
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
| | - Pardis Ghafarian
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, 19569-44413, Tehran, Iran. .,PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Mehrdad Bakhshayesh-Karam
- Chronic Respiratory Diseases Research Center, National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, 19569-44413, Tehran, Iran.,PET/CT and Cyclotron Center, Masih Daneshvari Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Carlos F Uribe
- Department of Functional Imaging, BC Cancer, Vancouver, BC, Canada
| | - Arman Rahmim
- Departments of Radiology and Physics, University of British Columbia, Vancouver, Canada.,Department of Integrative Oncology, BC Cancer Research Centre, Vancouver, Canada
| | - Saeed Sarkar
- Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Reza Ay
- Department of Medical Physics and Biomedical Engineering, Tehran University of Medical Sciences, Tehran, Iran.,Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran
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Differences in edge artifacts between 68Ga- and 18F-PET images reconstructed using point spread function correction. Nucl Med Commun 2019; 40:1166-1173. [PMID: 31469808 DOI: 10.1097/mnm.0000000000001079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Edge artifacts have been reported on in relation to F-PET using point spread function correction algorithms. The positron range of Ga is longer than F, and this difference is thought to result in different edge artifacts. The purpose of this study is to clarify the difference in edge artifacts in PET images using point spread function correction in Ga- and F-PET. METHODS We used a National Electrical Manufacturers Association International Electrotechnical Commission body phantom. The phantom was filled severally with Ga and F solution. The PET data were obtained over a 90 minutes period using a True Point Biograph 16 scanner. The images were then reconstructed with the ordered subset expectation maximization with point spread function correction. The phantom image analyses were performed by a visual assessment of the PET images and profiles, and an absolute recovery coefficient, which was the ratio of the maximum radioactivity of any given hot sphere to its true radioactivity. RESULTS The ring-like edge artifacts of Ga-PET were less prominent than those in F-PET. The relative radioactivity profiles of Ga-PET showed low overshoots of the maximum radioactivity although high overshoots did appear in F-PET. The absolute recovery coefficients of Ga-PET were smaller than those of F-PET. CONCLUSION The edge artifacts of Ga-PET were less prominent than those of F-PET, and their overshoots were smaller. The difference in the positron range between Ga and F may possibly result in the difference in edge artifacts of images reconstructed using the point spread function correction algorithm.
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Point Spread Function Reconstruction for Integrated 18F-FET PET/MRI in Patients With Glioma: Does It Affect SUVs and Respective Tumor-to-Background Ratios? Clin Nucl Med 2019; 44:e280-e285. [PMID: 30562198 DOI: 10.1097/rlu.0000000000002423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Semiquantitative F-FET PET assessment using the tumor's SUV or tumor-to-background ratios (TBRs) can separate gliomas from peritumoral tissue or progression from pseudoprogression. This study investigated if point spread function (PSF) reconstruction of F-FET PET data affects SUV-based dignity assessment. MATERIALS AND METHODS This study is a retrospective analysis of 87 glioma patients (female, 36; male, 51; age, 48 [13-81] years) undergoing F-FET PET/MRI for staging (n = 17) or restaging (n = 70). PET was reconstructed using ordered-subset expectation maximization with and without PSF. Lesions were delineated with semiautomated background-adapted thresholding relative to SUVmax; background was delineated contralaterally. Comparative measurements with a National Electrical Manufacturers Association International Electrotechnical Commission PET body phantom (sphere-to-background ratios, 8:1 and 4:1) were performed. RESULTS PSF showed significantly higher tumor SUVmax (median difference, +0.1; interquartile range, 0.04-0.18), SUVmean (+0.05; 0.03-0.08), TBRmax|mean (+0.1; 0.04-0.2), and TBRmean|mean (+0.06; 0.03-0.09) than non-PSF (P < 0.001). Background SUVmean was unaffected. In patients and phantom, differences between PSF and non-PSF increased with TBR and decreased with lesion's PET volume. Differences only exceeded 0.2 SUV for SUVmax or 0.1 SUV for SUVmean if TBR was greater than 3 and lesion's PET volume was less than 10 mL (d = 27 mm). Dignity assessment by PSF and non-PSF was concordant in all patients examined for staging (cutoff, TBRmean|mean > 1.6; positive, 14; negative, 3) and restaging (cutoff, TBRmax|mean > 2.0; positive, 67; negative, 3). CONCLUSIONS PSF increased tumor SUVmax and SUVmean compared with non-PSF F-FET PET/MRI data, especially in small lesions with high TBR (>3). However, dignity assessment using established TBR cutoffs was not affected.
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Akerele MI, Wadhwa P, Silva-Rodriguez J, Hallett W, Tsoumpas C. Validation of the physiological background correction method for the suppression of the spill-in effect near highly radioactive regions in positron emission tomography. EJNMMI Phys 2018; 5:34. [PMID: 30519974 PMCID: PMC6281548 DOI: 10.1186/s40658-018-0233-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 11/20/2018] [Indexed: 11/12/2022] Open
Abstract
Background Positron emission tomography (PET) imaging has a wide applicability in oncology, cardiology and neurology. However, a major drawback when imaging very active regions such as the bladder is the spill-in effect, leading to inaccurate quantification and obscured visualisation of nearby lesions. Therefore, this study aims at investigating and correcting for the spill-in effect from high-activity regions to the surroundings as a function of activity in the hot region, lesion size and location, system resolution and application of post-filtering using a recently proposed background correction technique. This study involves analytical simulations for the digital XCAT2 phantom and validation acquiring NEMA phantom and patient data with the GE Signa PET/MR scanner. Reconstructions were done using the ordered subset expectation maximisation (OSEM) algorithm. Dedicated point-spread function (OSEM+PSF) and a recently proposed background correction (OSEM+PSF+BC) were incorporated into the reconstruction for spill-in correction. The standardised uptake values (SUV) were compared for all reconstruction algorithms. Results The simulation study revealed that lesions within 15–20 mm from the hot region were predominantly affected by the spill-in effect, leading to an increased bias and impaired lesion visualisation within the region. For OSEM, lesion SUVmax converged to the true value at low bladder activity, but as activity increased, there was an overestimation as much as 19% for proximal lesions (distance around 15–20 mm from the bladder edge) and 2–4% for distant lesions (distance larger than 20 mm from the bladder edge). As bladder SUV increases, the % SUV change for proximal lesions is about 31% and 6% for SUVmax and SUVmean, respectively, showing that the spill-in effect is more evident for the SUVmax than the SUVmean. Also, the application of post-filtering resulted in up to 65% increment in the spill-in effect around the bladder edges. For proximal lesions, PSF has no major improvement over OSEM because of the spill-in effect, coupled with the blurring effect by post-filtering. Within two voxels around the bladder, the spill-in effect in OSEM is 42% (32%), while for OSEM+PSF, it is 31% (19%), with (and without) post-filtering, respectively. But with OSEM+PSF+BC, the spill-in contribution from the bladder was relatively low (below 5%, either with or without post-filtering). These results were further validated using the NEMA phantom and patient data for which OSEM+PSF+BC showed about 70–80% spill-in reduction around the bladder edges and increased contrast-to-noise ratio up to 36% compared to OSEM and OSEM+PSF reconstructions without post-filtering. Conclusion The spill-in effect is dependent on the activity in the hot region, lesion size and location, as well as post-filtering; and this is more evident in SUVmax than SUVmean. However, the recently proposed background correction method facilitates stability in quantification and enhances the contrast in lesions with low uptake. Electronic supplementary material The online version of this article (10.1186/s40658-018-0233-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mercy I Akerele
- Biomedical Imaging Science Department, School of Medicine, University of Leeds, Leeds, West Yorkshire, UK
| | - Palak Wadhwa
- Biomedical Imaging Science Department, School of Medicine, University of Leeds, Leeds, West Yorkshire, UK.,Invicro, Hammersmith Hospital, London, UK
| | - Jesus Silva-Rodriguez
- Molecular Imaging Research Group, Health Research Institute of Santiago de Compostela (IDIS), Santiago de Compostela, Galicia, Spain
| | | | - Charalampos Tsoumpas
- Biomedical Imaging Science Department, School of Medicine, University of Leeds, Leeds, West Yorkshire, UK. .,Invicro, Hammersmith Hospital, London, UK.
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Ciappuccini R, Desmonts C, Licaj I, Blanc-Fournier C, Bardet S, Aide N. Optimization of a dedicated protocol using a small-voxel PSF reconstruction for head-and-neck 18FDG PET/CT imaging in differentiated thyroid cancer. EJNMMI Res 2018; 8:104. [PMID: 30511173 PMCID: PMC6277402 DOI: 10.1186/s13550-018-0461-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 11/21/2018] [Indexed: 11/20/2022] Open
Abstract
Background 18FDG PET/CT is crucial before neck surgery for nodal recurrence localization in iodine-refractory differentiated or poorly differentiated thyroid cancer (DTC/PDTC). A dedicated head-and-neck (HN) acquisition performed with a thin matrix and point-spread-function (PSF) modelling in addition to the whole-body PET study has been shown to improve the detection of small cancer deposits. Different protocols have been reported with various acquisition times of HN PET/CT. We aimed to compare two reconstruction algorithms for disease detection and to determine the optimal acquisition time per bed position using the Siemens Biograph6 with extended field-of-view. Methods Twenty-one consecutive and unselected patients with DTC/PDTC underwent HN PET/CT acquisition using list-mode. PET data were reconstructed, mimicking five different acquisition times per bed position from 2 to 10 min. Each PET data set was reconstructed using 3D-ordered subset expectation maximisation (3D-OSEM) or iterative reconstruction with PSF modelling with no post filtering (PSFallpass). These reconstructions resulted in 210 anonymized datasets that were randomly reviewed to assess 18FDG uptake in cervical lymph nodes or in the thyroid bed using a 5-point scale. Noise level, maximal standard uptake values (SUVmax), tumour/background ratios (TBRs) and dimensions of the corresponding lesion on the CT scan were recorded. In surgical patients, the largest tumoral size of each lymph node metastasis was measured by a pathologist. Results The 120 HN PET studies of the 12 patients with at least 1 18FDG focus scored malignant formed the study group. Noise level significantly decreased between 2 and 4 min for both 3D-OSEM and PSFallpass reconstructions (p < 0.01). TBRs were similar for all the acquisition times for both 3D-OSEM and PSFallpass reconstructions (p = 0.25 and 0.44, respectively). The detection rate of malignant foci significantly improved from 2 to 10 min for PSFallpass reconstruction (20/26 to 26/26; p = 0.01) but not for 3D-OSEM (15/26 to 19/26; p = 0.26). For each of the five acquisition times, PSFallpass detected more malignant foci than 3D-OSEM (p < 0.01). In the seven surgical patients, PSFallpass evidenced smaller malignant lymph nodes than 3D-OSEM at 8 and 10 min. At 10 min, the mean size of the lymph node metastases neither detected with PSFallpass nor 3D-OSEM was 3 ± 0.6 mm vs 5.8 ± 1.1 mm for those detected with PSFallpass only and 10.9 ± 3.3 for those detected with both reconstructions (p < 0.001). Conclusions PSFallpass HN PET improves lesion detectability as compared with 3D-OSEM HN PET. PSFallpass with an acquisition time between 8 and 10 min provides the best performance for tumour detection.
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Affiliation(s)
- Renaud Ciappuccini
- Department of Nuclear Medicine and Thyroid Unit, François Baclesse Cancer Centre, 3 Avenue Général Harris, 14000, Caen, France. .,INSERM 1086 ANTICIPE, Normandie University, Caen, France.
| | - Cédric Desmonts
- Department of Nuclear Medicine, University Hospital, Caen, France
| | - Idlir Licaj
- Department of Clinical Research, François Baclesse Cancer Centre, Caen, France
| | | | - Stéphane Bardet
- Department of Nuclear Medicine and Thyroid Unit, François Baclesse Cancer Centre, 3 Avenue Général Harris, 14000, Caen, France
| | - Nicolas Aide
- INSERM 1086 ANTICIPE, Normandie University, Caen, France.,Department of Nuclear Medicine, University Hospital, Caen, France
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Rausch I, Ruiz A, Valverde-Pascual I, Cal-González J, Beyer T, Carrio I. Performance Evaluation of the Vereos PET/CT System According to the NEMA NU2-2012 Standard. J Nucl Med 2018; 60:561-567. [PMID: 30361382 DOI: 10.2967/jnumed.118.215541] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/17/2018] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to evaluate the physical performance of the Vereos whole-body PET/CT system according to the National Electrical Manufacturers Association (NEMA) NU2-2012 standard and to compare it with other state-of-the-art PET/CT systems. Methods: Spatial resolution, sensitivity, count-rate performance, count rate accuracy, and image quality were assessed. Specifically, spatial resolution was measured using an 18F point-source. System sensitivity was calculated from acquisitions of an 18F line source inside aluminum tubes of varying thickness. Assessment of count rate performance and count rate accuracy was based on measurements of an 18F line source inside a 20-cm-diameter polyethylene cylinder. PET image quality was assessed using a NEMA IQ phantom. All measurements were performed according to the predefined and implemented NEMA NU2-2012 acquisition protocols at a clinical installation of a Vereos PET/CT system. Evaluation was performed using the software provided by the vendor. Results: The average (radial and tangential) transverse spatial resolution was 4.2, 4.5, and 5.5 mm in full width at half maximum for a 1-, 10-, and 20-cm radial offset, respectively, from the center of the field of view. Axial spatial resolution varied between 4.2 and 4.6 mm in full width at half maximum, depending on the radial source position. The average sensitivity was 5.2 cps/kBq. A peak noise-equivalent count (NEC) rate of 153.4 kcps was measured at an activity concentration of 54.9 kBq/mL. The scatter fraction at peak NEC rate was 33.9%, and the maximum count rate error at and below peak NEC rate was 6.8%. Contrast recovery coefficients varied from 54.3% (10-mm sphere) to 83.9% (22-mm sphere) for the hot spheres, and between 81.4% (28-mm sphere) and 87% (37-mm sphere) for the cold spheres for a given sphere-to-background ratio of 4:1. Conclusion: The overall performance characteristics of the Vereos PET/CT system are comparable to state-of-the-art whole-body PET/CT systems with the exception that the peak NEC rate occurs at a higher activity concentration, thus indicating the ability of the Vereos PET/CT system to cover a wider range of activities.
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Affiliation(s)
- Ivo Rausch
- QIMP Team, Center of Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Agustin Ruiz
- Department of Medical Physics and Radiation Protection, Hospital Santa Creu i Sant Pau, Barcelona, Catalonia/Spain; and
| | - Itziar Valverde-Pascual
- Department of Medical Physics and Radiation Protection, Hospital Santa Creu i Sant Pau, Barcelona, Catalonia/Spain; and
| | - Jacobo Cal-González
- QIMP Team, Center of Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Thomas Beyer
- QIMP Team, Center of Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ignasi Carrio
- Department of Nuclear Medicine, Hospital Santa Creu i Sant Pau, Barcelona, Catalonia/Spain
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Benouaich V, Hitzel A, Armand S. Relevance of functional imaging in dental implantology. J Clin Exp Dent 2018; 10:e1011-e1016. [PMID: 30386508 PMCID: PMC6203899 DOI: 10.4317/jced.54816] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 04/26/2018] [Indexed: 01/16/2023] Open
Abstract
Background Despite it is widely used in many medicine fields, the use of functional imaging to examine dental implants has not been reported in the literature. This work aimed to evaluate the relevance of functional medical imaging in oral implantology. Material and Methods This single-center observational study was conducted for 6 months at the Toulouse University Hospital, France. All patients who underwent positron emission tomography with 18-fluorodeoxyglucose integrated with X-ray computed tomography (FDG PET/CT) and had dental implants were included. Metabolic activity of the peri-implant tissues was assessed qualitatively and quantitatively jointly by a nuclear physician and a dental surgeon. Results In 31 patients (121 implants), peri-implant metabolic activity was normal. In 3 patients (4 implants), localized peri-implant hypermetabolism was observed. In all the patients presenting abnormal peri-implant activity, the implants with normal activity were clinicaly and radiogicaly normal, whereas those with hypermetabolism presented peri-implantitis. Conclusions This study assess of the relevance of FDG PET/CT in oral implantology. It shows a link between peri-implant hypermetabolism and peri-implantitis. Therefore, FDG PET/CT could become a new tool for the assessment of peri-implant diseases. Key words:Dental implantation, dental implants, peri-implantitis, diagnostic imaging , imaging, three-dimensional, imaging processing, computer-assisted.
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Affiliation(s)
- Vincent Benouaich
- Doctor of Dental Surgery, Department of Odontology, Toulouse University Hospital, France
| | - Anne Hitzel
- Doctor of Medicine, Department of Nuclear Medicine, Toulouse University Hospital, France
| | - Serge Armand
- Doctor of Dental Surgery, University Professor, Department of Odontology, Toulouse University Hospital, France
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Jönsson L, Stenvall A, Mattsson E, Larsson E, Sundlöv A, Ohlsson T, Hindorf C. Quantitative analysis of phantom studies of 111In and 68Ga imaging of neuroendocrine tumours. EJNMMI Phys 2018; 5:5. [PMID: 29460190 PMCID: PMC5818391 DOI: 10.1186/s40658-018-0204-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 01/16/2018] [Indexed: 11/24/2022] Open
Abstract
Background Nuclear medicine imaging of neuroendocrine tumours is performed either by SPECT/CT imaging, using 111In-octreotide or by PET/CT imaging using 68Ga-radiolabelled somatostatin analogs. These imaging techniques will give different image quality and different detection thresholds for tumours, depending on size and activity uptake. The aim was to evaluate the image quality for 111In-SPECT and 68Ga-PET imaging, i.e. the smallest volume possible to visualize for different source-to-background activity ratios. The accuracy of quantification of lesion volume and activity was also investigated to develop an objective evaluation for radionuclide therapy eligibility. The phantom study was performed using the NEMA IEC Body Phantom with six hot spheres having inner diameters of 10, 13, 17, 22, 28, and 37 mm, filled with either 68Ga or 111In with sphere-to-background ratios (SBRs) of no background activity, 5:1, 2.5:1, and 1.25:1. Activity ratios of 1.25:1 and 2.5:1 are clinically found for lesions close to the liver and spleen. Clinical acquisition and reconstruction protocols were applied. Line profiles were drawn to evaluate the smallest detectable volume within a given SBR. Recovery curves based on threshold-based VOIs, threshold-based VOIs adapted to the background and CT-based ROIs were obtained for all SBRs and sphere diameters, allowing for quantification. Results The 10-mm sphere was not possible to detect in SPECT images. It was detectable in PET images for SBRs of 2.5:1 and higher. In a background corresponding to the activity uptake in the liver, spheres larger than 22–37 mm were detectable in the 111In-SPECT images and spheres larger than 13–22 mm were detectable in the 68Ga-PET images. The maximum activity concentration was accurately quantified for spheres larger than 22 mm in the PET images; however, the quantification was impaired by sphere size and background activity. Conclusions It was not possible to detect the 10-mm sphere in any of the SPECT images. In a background corresponding to the activity uptake in the liver, spheres larger than approximately 30 mm were visible in the 111In-SPECT images and spheres larger than approximately 17 mm were visible in the 68Ga-PET images. Sphere diameter and background activity strongly affect the possibility of a correct quantification.
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Affiliation(s)
- L Jönsson
- Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden.
| | - A Stenvall
- Department of Medical Radiation Physics, Clinical Sciences, Lund University, Lund, Sweden
| | - E Mattsson
- Department of Hospital Physics, County Hospital Ryhov, Jönköping, Sweden
| | - E Larsson
- Department of Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - A Sundlöv
- Department of Oncology and Pathology, Clinical Sciences Lund University, Lund, Sweden
| | - T Ohlsson
- Department of Radiation Physics, Skåne University Hospital, Lund, Sweden
| | - C Hindorf
- Department of Radiation Physics, Skåne University Hospital, Lund, Sweden
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Lasnon C, Enilorac B, Popotte H, Aide N. Impact of the EARL harmonization program on automatic delineation of metabolic active tumour volumes (MATVs). EJNMMI Res 2017; 7:30. [PMID: 28361349 PMCID: PMC5374086 DOI: 10.1186/s13550-017-0279-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 03/16/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The clinical validation of the EARL harmonization program for standardised uptake value (SUV) metrics is well documented; however, its potential for defining metabolic active tumour volume (MATV) has not yet been investigated. We aimed to compare delineation of MATV on images reconstructed using conventional ordered subset expectation maximisation (OSEM) with those reconstructed using point spread function modelling (PSF-reconstructed images), and either optimised for diagnostic potential (PSF) or filtered to meet the EANM/EARL harmonising standards (PSF7). METHODS Images from 18 stage IIIA-IIIB lung cancer patients were reconstructed using all the three methods. MATVs were then delineated using both a 40% isocontour and a gradient-based method. MATVs were compared by means of Bland-Altman analyses, and Dice coefficients and concordance indices based on the unions and intersections between each pair of reconstructions (PSF vs OSEM, PSF7 vs PSF and PSF7 vs OSEM). RESULTS Using the 40% isocontour method and taking the MATVs delineated on OSEM images as a reference standard, the use of PSF7 images led to significantly higher Dice coefficients (median value = 0.96 vs 0.77; P < 0.0001) and concordance indices (median value = 0.92 vs 0.64; P < 0.0001) than those obtained using PSF images. The gradient-based methodology was less sensitive to reconstruction variability than the 40% isocontour method; Dice coefficients and concordance indices were superior to 0.8 for both PSF reconstruction methods. However, the use of PSF7 images led to narrower interquartile ranges and significantly higher Dice coefficients (median value = 0.96 vs 0.94; P = 0.01) and concordance indices (median value = 0.89 vs 0.85; P = 0.003) than those obtained with PSF images. CONCLUSION This study demonstrates that automatic contouring of lung tumours on EARL-compliant PSF images using the widely adopted automatic isocontour methodology is an accurate means of overcoming reconstruction variability in MATV delineation. Although gradient-based methodology appears to be less sensitive to reconstruction variability, the use of EARL-compliant PSF images significantly improved the Dice coefficients and concordance indices, demonstrating the importance of harmonised-images, even when more advanced contouring algorithms are used.
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Affiliation(s)
- Charline Lasnon
- Nuclear Medicine Department, François Baclesse Cancer Centre, Caen, France
- INSERM U1086 « ANTICIPE », BioTICLA, François Baclesse Cancer Centre, Caen, France
| | - Blandine Enilorac
- Nuclear Medicine Department, University Hospital, Avenue Côte de Nacre, 14000 Caen, France
| | - Hosni Popotte
- Radiation Oncology, François Baclesse Cancer Centre, Caen, France
| | - Nicolas Aide
- INSERM U1086 « ANTICIPE », BioTICLA, François Baclesse Cancer Centre, Caen, France
- Nuclear Medicine Department, University Hospital, Avenue Côte de Nacre, 14000 Caen, France
- Normandie University, Caen, France
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Nakazawa S, Umeda T, Miyaji N, Miwa K, Wagatsuma K, Motegi K, Takiguchi T, Terauchi T, Koizumi M, Usui K, Sasai K. Calculation Accuracy of Gross Tumor Volume at the Diaphragm Boundary Evaluated Using Respiratory-gated PET/CT. Nihon Hoshasen Gijutsu Gakkai Zasshi 2017; 73:617-625. [PMID: 28824085 DOI: 10.6009/jjrt.2017_jsrt_73.8.617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The present study aimed to clarify gross tumor volume (GTV) contouring accuracy at the diaphragm boundary using respiratory-gated PET/CT. METHODS The lung/diaphragm boundary was simulated using a phantom containing 18F solution (10.6 kBq/mL). Tumors were simulated using spheres (diameter, 11-38 mm) containing 18F and located at the positions of the lungs and liver. The tumor background ratios (TBR) were 2, 4, and 8. The phantom was moved from the superior to inferior direction with a 20-mm motion displacement at 3.6 s intervals. The recovery coefficient (RC), volume RC (VRC), and standardized uptake value (SUV) threshold were calculated using stationary, non-gated (3D), and gated (4D) PET/CT. RESULTS In lung cancer simulation, RC and VRC in 3D PET images were, respectively, underestimated and overestimated in smaller tumors, whereas both improved in 4D PET images regardless of tumor size and TBR. The optimal SUV threshold was about 30% in 4D PET images. In liver cancer simulation, RC and VRC were, respectively, underestimated and overestimated in smaller tumors, and when the TBR was lower, but both improved in 4D PET images when tumors were >17 mm and the TBR was >4. The optimal SUV threshold tended to depend on the TBR. CONCLUSIONS The contouring accuracy of GTV was improved by considering TBR and using an optimal SUV threshold acquired from 4D PET images.
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Affiliation(s)
- Shuto Nakazawa
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research.,Department of Radiation Oncology, Graduate School of Medicine, Juntendo University
| | - Takuro Umeda
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Noriaki Miyaji
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Kenta Miwa
- School of Health Science, International University of Health and Welfare
| | - Kei Wagatsuma
- Research Team for Neuroimaging, Tokyo Metropolitan Institute of Gerontology
| | - Kazuki Motegi
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Tomohiro Takiguchi
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Takashi Terauchi
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Mitsuru Koizumi
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Keisuke Usui
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University
| | - Keisuke Sasai
- Department of Radiation Oncology, Faculty of Medicine, Juntendo University
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Jonasson LS, Axelsson J, Riklund K, Boraxbekk CJ. Simulating effects of brain atrophy in longitudinal PET imaging with an anthropomorphic brain phantom. Phys Med Biol 2017; 62:5213-5227. [PMID: 28561014 DOI: 10.1088/1361-6560/aa6e1b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
In longitudinal positron emission tomography (PET), the presence of volumetric changes over time can lead to an overestimation or underestimation of the true changes in the quantified PET signal due to the partial volume effect (PVE) introduced by the limited spatial resolution of existing PET cameras and reconstruction algorithms. Here, a 3D-printed anthropomorphic brain phantom with attachable striata in three sizes was designed to enable controlled volumetric changes. Using a method to eliminate the non-radioactive plastic wall, and manipulating BP levels by adding different number of events from list-mode acquisitions, we investigated the artificial volume dependence of BP due to PVE, and potential bias arising from varying BP. Comparing multiple reconstruction algorithms we found that a high-resolution ordered-subsets maximization algorithm with spatially variant point-spread function resolution modeling provided the most accurate data. For striatum, the BP changed by 0.08% for every 1% volume change, but for smaller volumes such as the posterior caudate the artificial change in BP was as high as 0.7% per 1% volume change. A simple gross correction for striatal volume is unsatisfactory, as the amplitude of the PVE on the BP differs depending on where in the striatum the change occurred. Therefore, to correctly interpret age-related longitudinal changes in the BP, we must account for volumetric changes also within a structure, rather than across the whole volume. The present 3D-printing technology, combined with the wall removal method, can be implemented to gain knowledge about the predictable bias introduced by the PVE differences in uptake regions of varying shape.
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Affiliation(s)
- L S Jonasson
- Department of Radiation Sciences, Diagnostic Radiology, Umeå University, Umeå, Sweden. Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden. Center for Demographic and Aging Research, Umeå University, Umeå Sweden
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Encaoua J, Abgral R, Leleu C, El Kabbaj O, Caradec P, Bourhis D, Pradier O, Schick U. Intérêt de la tomographie par émission de positons au ( 18 F)-fluorodésoxyglucose pour la planification de la radiothérapie des cancers de l’œsophage localement évolués ou inopérables. Cancer Radiother 2017; 21:267-275. [DOI: 10.1016/j.canrad.2016.12.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 09/10/2016] [Accepted: 12/18/2016] [Indexed: 12/13/2022]
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30
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Riegler G, Karanikas G, Rausch I, Hirtl A, El-Rabadi K, Marik W, Pivec C, Weber M, Prosch H, Mayerhoefer M. Influence of PET reconstruction technique and matrix size on qualitative and quantitative assessment of lung lesions on [18F]-FDG-PET: A prospective study in 37 cancer patients. Eur J Radiol 2017; 90:20-26. [PMID: 28583635 DOI: 10.1016/j.ejrad.2017.02.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 02/09/2017] [Accepted: 02/15/2017] [Indexed: 12/18/2022]
Abstract
PURPOSE To evaluate the influence of point spread function (PSF)-based reconstruction and matrix size for PET on (1) lung lesion detection and (2) standardized uptake values (SUV). METHODS This prospective study included oncological patients who underwent [18F]-FDG-PET/CT for staging. PET data were reconstructed with a 2D ordered subset expectation maximization (OSEM) algorithm, and a 2D PSF-based algorithm (TrueX), separately with two matrix sizes (168×168 and 336×336). The four PET reconstructions (TrueX-168; OSEM-168; TrueX-336; and OSEM-336) were read independently by two raters, and PET-positive lung lesions were recorded. Blinded to the PET findings, a third independent rater assessed lung lesions with diameters of >4mm on CT. Subsequently, PET and CT were reviewed side-by side in consensus. Multi-factorial logistic regression analyses and two-way repeated measures analyses of variance (ANOVA) were performed. RESULTS Thirty-seven patients with 206 lung lesions were included. Lesion-based PET sensitivities differed significantly between reconstruction algorithms (P<0.001) and between reconstruction matrices (P=0.022). Sensitivities were 94.2% and 88.3% for TrueX-336; 88.3% and 85.9% for TrueX-168; 67.8% and 66.3% for OSEM-336; and 67.0% and 67.9% for OSEM-168; for rater 1 and rater 2, respectively. SUVmax and SUVmean were significantly higher for images reconstructed with 336×336 matrices than for those reconstructed with 168×168 matrices (P<0.001). CONCLUSION Our results demonstrate that PSF-based PET reconstruction, and, to a lesser degree, higher matrix size, improve detection of metabolically active lung lesions. However, PSF-based PET reconstructions and larger matrix sizes lead to higher SUVs, which may be a concern when PET data from different institutions are compared.
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Affiliation(s)
- Georg Riegler
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria.
| | - Georgios Karanikas
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Ivo Rausch
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Albert Hirtl
- Medical University of Vienna, Center for Medical Physics and Biomedical Engineering, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Karem El-Rabadi
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Wolfgang Marik
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Christopher Pivec
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Michael Weber
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Helmut Prosch
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
| | - Marius Mayerhoefer
- Medical University of Vienna, Department of Biomedical Imaging and Image-guided Therapy, Währingergürtel 18-20, 1090 Vienna, Austria
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Impact of point spread function reconstruction on quantitative 18F-FDG-PET/CT imaging parameters and inter-reader reproducibility in solid tumors. Nucl Med Commun 2016; 37:288-96. [DOI: 10.1097/mnm.0000000000000445] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Akamatsu G. [Point-spread Function and Time-of-flight in PET Image Reconstruction]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2015; 71:1115-1122. [PMID: 26596203 DOI: 10.6009/jjrt.2015_jsrt_71.11.1115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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Akamatsu G, Nishida H, Fujino A, Ohnishi A, Ikari Y, Nishio T, Maebatake A, Sasaki M, Senda M. [Harmonization of Standardized Uptake Value among Different Generation PET/ CT Cameras Based on a Phantom Experiment -Utility of SUV(peak)]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2015; 71:735-745. [PMID: 26400557 DOI: 10.6009/jjrt.2015_jsrt_71.9.735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Standardized uptake value (SUV) has been widely used as a semi-quantitative metric of uptake in FDGPET/ CT for diagnosis of malignant tumors and evaluation of tumor therapies. However, the SUV depends on various factors including PET/CT scanner specifications and reconstruction parameters. The purpose of this study is to harmonize the SUV among two PET/CT models of different generation: two units of Discovery ST Elite Performance(DSTEP) and Discovery 690 (D690) PET/CT scanners. The NEMA body phantom filled with 18F solution was scanned for 30 minutes in list-mode. The D690 PET images were reconstructed with OSEM, OSEM+TOF, and OSEM+PSF. Gaussian post-filters of 4-9 mm FWHM were applied to find the parameters that provides harmonized SUV. We determined the SUV-harmonized parameter for each reconstruction algorithm. Then, the 10 PET images simulating clinical scan conditions were respectively generated to evaluate the bias and variability of SUV(max) and SUV(peak). The SUV(max) strongly depended not only on spatial resolution but also on image noise. On the other hand, the SUV(peak) was a robust metric to image noise level. TOF improved the variability of SUV(max) and SUV(peak). Thus, we were able to harmonize the spatial resolution using SUV(peak) based on the phantom study. Because SUV(max) was also strongly affected by image noise, sufficient count statistics is essential for SUV(max) harmonization. We recommended that TOF reconstruction and SUV(peak) metric should be used to harmonize SUV.
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Affiliation(s)
- Go Akamatsu
- Department of Radiological Technology, Institute of Biomedical Research and Innovation
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Rogasch JM, Steffen IG, Hofheinz F, Großer OS, Furth C, Mohnike K, Hass P, Walke M, Apostolova I, Amthauer H. The association of tumor-to-background ratios and SUVmax deviations related to point spread function and time-of-flight F18-FDG-PET/CT reconstruction in colorectal liver metastases. EJNMMI Res 2015; 5:31. [PMID: 25992306 PMCID: PMC4427576 DOI: 10.1186/s13550-015-0111-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/22/2015] [Indexed: 01/11/2023] Open
Abstract
Background The maximum standardized uptake value (SUVmax) is a common clinical parameter for quantification in F18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT), but it is influenced by image reconstruction. The aim of this study was to analyze the association of SUVmax deviations related to point spread function (PSF) and time-of-flight (TOF) reconstruction with tumor-to-background ratios (TBR) in colorectal liver metastases (CRLM). Methods Fifteen patients (f, 6; m, 9; median age, 59 years; range, 32 to 72 years) with 28 liver metastases were included retrospectively. FDG-PET/CT imaging (median activity, 237 MBq; range, 231 to 252 MBq; median uptake, 61 min; range, 55 to 67 min) was performed on a Siemens Biograph mCT 64 followed by image reconstruction using 3D-ordered subset expectation maximization (3D-OSEM) or 3D-OSEM with PSF modeling - both with and without TOF information. Differences in SUVmax were analyzed using the Friedman test and Wilcoxon test for paired non-parametric data. The correlation of inter-method differences with the lesions’ TBR was studied using Spearman’s rank correlation coefficient (rho). Differences between lesions with low (<4.8) and high (>4.8) TBR were analyzed using the Mann-Whitney U test (TBR measured with 3D-OSEM; binarized by its median). Results There was a significant correlation of the lesions’ TBR with relative SUVmax differences related to PSF (PSF + TOF vs. 3D-OSEM + TOF, rho = 0.61; PSF vs. 3D-OSEM, rho = 0.52) or TOF (PSF + TOF vs. PSF, rho = −0.58; 3D-OSEM + TOF vs. 3D-OSEM, rho = −0.61). Accordingly, PSF algorithms only showed higher SUVmax than non-PSF algorithms in lesions with a high TBR (median differences at low/high TBR, +2.6%/+9.1% [PSF + TOF vs. 3D-OSEM + TOF]; +0.7%/+6.4% [PSF vs. 3D-OSEM]). TOF integration also led to higher SUVmax but mainly at low TBR (low/high TBR, +10.4%/+1.8% [PSF + TOF vs. PSF]; +8.6%/−0.1% [3D-OSEM + TOF vs. 3D-OSEM]). Conclusions Both PSF and TOF reconstruction resulted in a substantial alteration of SUVmax in CRLM. TOF provided the highest SUVmax increase in low-contrast lesions while - vice versa - PSF showed the most relevant increase in high-contrast lesions. Thus, one should be aware that quantitative analyses of lesions with varying TBR, e.g., in radiotherapy or follow-up studies, may be mainly affected by either PSF or TOF reconstruction, respectively.
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Affiliation(s)
- Julian Mm Rogasch
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Ingo G Steffen
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Frank Hofheinz
- Helmholtz-Zentrum Dresden-Rossendorf, PET Center, Institute of Radiopharmaceutical Cancer Research, Bautzner Landstraße 400, Dresden, 01328 Germany
| | - Oliver S Großer
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Christian Furth
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Konrad Mohnike
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Peter Hass
- Klinik für Strahlentherapie, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Mathias Walke
- Klinik für Strahlentherapie, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Ivayla Apostolova
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
| | - Holger Amthauer
- Klinik für Radiologie und Nuklearmedizin, Universitätsklinikum Magdeburg A.ö.R., Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, Magdeburg, 39120 Germany
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