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Kim H, Li Z, Son J, Fessler JA, Dewaraja YK, Chun SY. Physics-Guided Deep Scatter Estimation by Weak Supervision for Quantitative SPECT. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:2961-2973. [PMID: 37104110 PMCID: PMC10593395 DOI: 10.1109/tmi.2023.3270868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Accurate scatter estimation is important in quantitative SPECT for improving image contrast and accuracy. With a large number of photon histories, Monte-Carlo (MC) simulation can yield accurate scatter estimation, but is computationally expensive. Recent deep learning-based approaches can yield accurate scatter estimates quickly, yet full MC simulation is still required to generate scatter estimates as ground truth labels for all training data. Here we propose a physics-guided weakly supervised training framework for fast and accurate scatter estimation in quantitative SPECT by using a 100× shorter MC simulation as weak labels and enhancing them with deep neural networks. Our weakly supervised approach also allows quick fine-tuning of the trained network to any new test data for further improved performance with an additional short MC simulation (weak label) for patient-specific scatter modelling. Our method was trained with 18 XCAT phantoms with diverse anatomies / activities and then was evaluated on 6 XCAT phantoms, 4 realistic virtual patient phantoms, 1 torso phantom and 3 clinical scans from 2 patients for 177Lu SPECT with single / dual photopeaks (113, 208 keV). Our proposed weakly supervised method yielded comparable performance to the supervised counterpart in phantom experiments, but with significantly reduced computation in labeling. Our proposed method with patient-specific fine-tuning achieved more accurate scatter estimates than the supervised method in clinical scans. Our method with physics-guided weak supervision enables accurate deep scatter estimation in quantitative SPECT, while requiring much lower computation in labeling, enabling patient-specific fine-tuning capability in testing.
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Affiliation(s)
- Hanvit Kim
- Digital Biomedical Research Division, Electronics and Telecommunications Research Institute, Daejeon, South Korea
- Department of Electrical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, South Korea
| | - Zongyu Li
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Jiye Son
- Interdisciplinary Program for Bioengineering, Seoul National University (SNU), Seoul, South Korea. This work was done when she was with the School of Electrical and Computer Engineering (ECE), UNIST
| | - Jeffrey A. Fessler
- Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA
| | - Yuni K. Dewaraja
- Dewaraja is with the Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Se Young Chun
- Department of ECE, INMC & IPAI, SNU, Seoul, South Korea
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Nichols KJ, Yoon SY, Van Tosh A, Palestro CJ. 99mTc-PYP SPECT and SPECT/CT quantitation for diagnosing cardiac transthyretin amyloidosis. J Nucl Cardiol 2023; 30:1235-1245. [PMID: 36352087 DOI: 10.1007/s12350-022-03133-y] [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: 04/21/2022] [Accepted: 09/18/2022] [Indexed: 11/11/2022]
Abstract
BACKGROUND We investigated quantitative 99mTc-pyrophosphate (PYP) SPECT/CT reproducibility and accuracy for diagnosing cardiac transthyretin amyloidosis (ATTR), and whether SPECT/CT improved visual and quantitative results compared to SPECT-only. METHODS Data were reviewed for 318 patients with suspected ATTR who underwent PYP SPECT/CT. Myocardial-to-blood pool count (MBP) ratios were computed and repeated independently > 1 month later. A physician independently scored LV myocardial-to-rib uptake on SPECT/CT as: 0 (negative), 1 < rib (equivocal), 2 = rib (positive) or 3 > rib (positive), and the image quality as: 1 (poor), 2 (adequate), and 3 (good). SPECT-only MBP ratios and visual scores were assessed separately for a subgroup of the first sequential 191 patients. RESULTS 25% of patients had positive myocardial uptake (myocardial-to-rib uptake score of ≥ 2). SPECT/CT MBP ratios were reproducible (1.35 ± .68 vs 1.33 ± .74, p = .09) and corresponded with visual scores ≥ 2 (ROC AUC = 99 ± 1%) more accurately than SPECT-only MBPs (93 ± 3%, p = .02). SPECT/CT image quality was better than that of SPECT-only (2.7 ± .5 vs 2.1 ± .5, p < .0001) with fewer equivocal results (2.6% vs 22.5%, p < .0001). CONCLUSION SPECT/CT produces MBP ratios that are reproducible and accurately identify a positive scan, with better image quality and fewer equivocal cases than SPECT-only.
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Affiliation(s)
- Kenneth J Nichols
- Department of Radiology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA.
- Division of Nuclear Medicine and Molecular Imaging, Northwell Health, 270-05 76th Avenue, New Hyde Park, NY, 10040, USA.
| | - Se-Young Yoon
- Department of Radiology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA
| | | | - Christopher J Palestro
- Department of Radiology, Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
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Absolute Quantification in Diagnostic SPECT/CT: The Phantom Premise. Diagnostics (Basel) 2021; 11:diagnostics11122333. [PMID: 34943570 PMCID: PMC8700635 DOI: 10.3390/diagnostics11122333] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 02/07/2023] Open
Abstract
The application of absolute quantification in SPECT/CT has seen increased interest in the context of radionuclide therapies where patient-specific dosimetry is a requirement within the European Union (EU) legislation. However, the translation of this technique to diagnostic nuclear medicine outside this setting is rather slow. Clinical research has, in some examples, already shown an association between imaging metrics and clinical diagnosis, but the applications, in general, lack proper validation because of the absence of a ground truth measurement. Meanwhile, additive manufacturing or 3D printing has seen rapid improvements, increasing its uptake in medical imaging. Three-dimensional printed phantoms have already made a significant impact on quantitative imaging, a trend that is likely to increase in the future. In this review, we summarize the data of recent literature to underpin our premise that the validation of diagnostic applications in nuclear medicine using application-specific phantoms is within reach given the current state-of-the-art in additive manufacturing or 3D printing.
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Goh KL, Liew SC. Dual-energy x-ray approach for object/energy-specific attenuation coefficient correction in single-photon emission computed tomography: effects of contrast agent. J Med Imaging (Bellingham) 2021; 8:052106. [PMID: 34084871 DOI: 10.1117/1.jmi.8.5.052106] [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: 10/29/2020] [Accepted: 05/11/2021] [Indexed: 11/14/2022] Open
Abstract
Purpose: To investigate the influence of radiographic contrast agent on the accuracy of the photon counts arising from the emission of gamma rays of radionuclides in single-photon emission computed tomography (SPECT), when dual-energy x-ray CT (DXCT) is employed for providing object/energy-specific attenuation coefficient correction in SPECT. Approach: Computer simulation was performed for three transmission CT approaches, namely, the conventional (single kVp, unimodal spectrum) x-ray CT, DXCT (single kVp, bimodal spectrum) with basis material decomposition (BMD), and DXCT with BMD followed by basis material coefficients transformation (BMT), to study the effects of these approaches on the accuracy of the photon counts from the SPECT image of a thorax-like phantom. Results: All three CT approaches revealed that the error in the counts was both photon energy and iodine concentration-dependent. Differences in the trending increase/decrease in the errors with the respective increase in iodine concentration and photon energy were observed among the three CT approaches. Of the three, the BMT/SPECT approach resulted in the smallest error in the concentration of radionuclides measured, especially in the contrast agent-filled region, and the optimal level depended on the iodine concentration and photon energy. Conclusion: With a judicious choice of the basis materials and photon energy, it may be possible to take advantage of the benefits of the BMT method to mitigate the accuracy problem in DXCT for quantitative SPECT imaging.
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Affiliation(s)
| | - Soo Chin Liew
- National University of Singapore, Center for Remote Imaging, Sensing and Processing and Department of Physics, Singapore
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Hao G, Mastren T, Silvers W, Hassan G, Öz OK, Sun X. Copper-67 radioimmunotheranostics for simultaneous immunotherapy and immuno-SPECT. Sci Rep 2021; 11:3622. [PMID: 33574346 PMCID: PMC7878802 DOI: 10.1038/s41598-021-82812-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 01/22/2021] [Indexed: 02/01/2023] Open
Abstract
Copper-67 (t1/2 = 2.58 days) decays by β- ([Formula: see text]: 562 keV) and γ-rays (93 keV and 185 keV) rendering it with potential for both radionuclide therapy and single-photon emission computed tomography (SPECT) imaging. Prompted by the recent breakthrough of 67Cu production with high specific activity, high radionuclidic purity, and sufficient quantities, the interest in the theranostic potential of 67Cu has been rekindled. This work addresses the practicability of developing 67Cu-labeled antibodies with substantially improved quality for cancer radioimmunotheranostics. Proof of concept is demonstrated with pertuzumab, a US-FDA-approved monoclonal antibody for combination therapies of HER2-positive breast cancer. With an average number of 1.9 chelators coupled to each antibody, we achieved a two-order of magnitude increase in radiolabeling efficiency compared to literature reports. In a preclinical therapeutic study, mice (n = 4-7/group) bearing HER2+ xenografts exhibited a 67Cu-dose dependent tumor-growth inhibition from 67Cu-labeled-Pertuzumab co-administered with trastuzumab. Furthermore, greater tumor size reduction was observed with 67Cu-labeled-pertuzumab formulations of higher specific activity. The potential of SPECT imaging with 67Cu radiopharmaceuticals was tested after 67Cu-labeled-Pertuzumab administration. Impressively, all tumors were clearly visualized by SPECT imaging with 67Cu-labeled-Pertuzumab even at day 5 post injection. This work demonstrates it is practical to use 67Cu radioimmunoconjugates for cancer radioimmunotheranostics.
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Affiliation(s)
- Guiyang Hao
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Tara Mastren
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - William Silvers
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Gedaa Hassan
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Orhan K Öz
- Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiankai Sun
- 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.
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Patient arm position during quantitative bone single-photon emission computed tomography/computed tomography acquisition can affect image quality and quantitative accuracy: a phantom study. Nucl Med Commun 2020; 42:267-275. [PMID: 33323866 DOI: 10.1097/mnm.0000000000001338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The present study used a phantom to determine the effects of various arm positions on bone SPECT/computed tomography (CT) images and the optimal arm position to acquire good-quality and quantitatively accurate images. MATERIALS AND METHODS We designed a phantom study of five simulated arm positions that are assumed during SPECT image acquisition. All SPECT data were acquired during a total of 120 projections of 10 and 100 s/view over 360° in a non-circular mode and reconstructed using Flash 3D (Siemens Healthineers). We evaluated contrast (QH,17 mm), image noise (NB,17 mm), contrast-to-noise ratios (QNRs), and visual scores according to the guidelines for bone SPECT acquisition protocols published by the Japanese Society of Nuclear Medicine Technology. The SUVmean, SUVmax, and SUVpeak were calculated and quantitative errors were evaluated using the recovery coefficient (RC) and the root means square error (RMSE). RESULTS The spatial resolution of SPECT images was better when the arms were down than raised with simulated shoulder disorders. Raised arms with shoulder disorders significantly increased the NB,17 mm and decreased the QH,17 mm, and the QNR in each image differed over a range from 2.2 to 5.2. The visual score was >1.5 with the arms down, raised normally, and raised with moderate shoulder disorders. The SUVmax and SUVpeak were overestimated compared with 100-min data for all images, whereas SUVmean was underestimated. Raised arms with a shoulder disorder decreased RCmax, and RCmean and RCpeak suppressed differences among arm positions. In addition, RMSE with the arms down and raised normally were close to that for 100-min data. CONCLUSION Bone SPECT images with good quality and quantitative accuracy can be acquired with patients holding their arms down by their sides. This will help patients with shoulder pain who have difficulties raising their arms.
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Annunziata S, Bauckneht M, Albano D, Argiroffi G, Calabrò D, Abenavoli E, Linguanti F, Laudicella R. Impact of the COVID-19 pandemic in nuclear medicine departments: preliminary report of the first international survey. Eur J Nucl Med Mol Imaging 2020; 47:2090-2099. [PMID: 32462398 PMCID: PMC7251803 DOI: 10.1007/s00259-020-04874-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 05/18/2020] [Indexed: 01/18/2023]
Abstract
PURPOSE Coronavirus disease-19 (COVID-19) pandemic is challenging the availability of hospital resources worldwide. The Young Group of the Italian Association of Nuclear Medicine (AIMN) developed the first international survey to evaluate the impact of COVID-19 in nuclear medicine (NM). The aim of this study was to perform a preliminary report of the ongoing survey. METHODS A questionnaire of thirty questions was prepared for all NM professionals addressing three main issues: (1) new scheduling praxes for NM diagnostic and therapeutic procedures, (2) assistance of patients with diagnosed or suspected COVID-19, and (3) prevention of COVID-19 spreading in the departments. An invitation to the survey was sent to the corresponding authors of NM scientific papers indexed in SCOPUS in 2019. Personal data were analysed per individual responder. Organisation data were evaluated per single department. RESULTS Two-hundred and ninety-six individual responders from 220 departments were evaluated. Most of the responders were from Europe (199/296, 67%). Approximately, all departments already changed their scheduling praxes due to the pandemic (213/220, 97%). In most departments, scheduled diagnostic and therapeutic procedures were allowed but quantitatively reduced (112/220, 51%). A significant reduction of diagnostic and therapeutic procedures (more than 20%) affected 198/220 (90%) and 158/220 (72%) departments, respectively. Incidental COVID-19 signs in NM exams occurred in 106/220 departments (48%). Few departments were closed or shifted to assist patients with COVID-19 (36/220, 16%). Most of the responders thought that pandemic would not permanently change the work of NM departments in the future (189/296, 64%). CONCLUSIONS According to this preliminary report of the first international survey, COVID-19 heavily impacted NM departments and professionals. New praxes for NM procedures, assistance, and prevention of COVID-19 have been applied during the pandemic.
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Affiliation(s)
- Salvatore Annunziata
- Nuclear Medicine Unit, IRCCS Regina Elena National Cancer Institute, via Elio Chianesi 53, 00144, Rome, Italy.
| | - Matteo Bauckneht
- Nuclear Medicine Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Domenico Albano
- Department of Nuclear Medicine, University of Brescia and Spedali Civili Brescia, Brescia, Italy
| | | | - Diletta Calabrò
- Nuclear Medicine, DIMES University of Bologna, S. Orsola-Malpighi Hospital, Bologna, Italy
| | - Elisabetta Abenavoli
- Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Flavia Linguanti
- Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Florence, Italy
| | - Riccardo Laudicella
- Department of Biomedical and Dental Sciences and of Morpho-Functional Imaging, Nuclear Medicine Unit, University of Messina, Messina, Italy
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