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Kerckhaert CEM, de Jong HWAM, Meddens MBM, van Rooij R, Smits MLJ, Rakvongthai Y, Dietze MMA. Subtraction of single-photon emission computed tomography (SPECT) in radioembolization: a comparison of four methods. EJNMMI Phys 2024; 11:72. [PMID: 39143361 PMCID: PMC11324633 DOI: 10.1186/s40658-024-00675-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 08/05/2024] [Indexed: 08/16/2024] Open
Abstract
BACKGROUND Subtraction of single-photon emission computed tomography (SPECT) images has a number of clinical applications in e.g. foci localization in ictal/inter-ictal SPECT and defect detection in rest/stress cardiac SPECT. In this work, we investigated the technical performance of SPECT subtraction for the purpose of quantifying the effect of a vasoconstricting drug (angiotensin-II, or AT2) on the Tc-99m-MAA liver distribution in hepatic radioembolization using an innovative interventional hybrid C-arm scanner. Given that subtraction of SPECT images is challenging due to high noise levels and poor resolution, we compared four methods to obtain a difference image in terms of image quality and quantitative accuracy. These methods included (i) image subtraction: subtraction of independently reconstructed SPECT images, (ii) projection subtraction: reconstruction of a SPECT image from subtracted projections, (iii) projection addition: reconstruction by addition of projections as a background term during the iterative reconstruction, and (iv) image addition: simultaneous reconstruction of the difference image and the subtracted image. RESULTS Digital simulations (XCAT) and phantom studies (NEMA-IQ and anthropomorphic torso) showed that all four methods were able to generate difference images but their performance on specific metrics varied substantially. Image subtraction had the best quantitative performance (activity recovery coefficient) but had the worst visual quality (contrast-to-noise ratio) due to high noise levels. Projection subtraction showed a slightly better visual quality than image subtraction, but also a slightly worse quantitative accuracy. Projection addition had a substantial bias in its quantitative accuracy which increased with less counts in the projections. Image addition resulted in the best visual image quality but had a quantitative bias when the two images to subtract contained opposing features. CONCLUSION All four investigated methods of SPECT subtraction demonstrated the capacity to generate a feasible difference image from two SPECT images. Image subtraction is recommended when the user is only interested in quantitative values, whereas image addition is recommended when the user requires the best visual image quality. Since quantitative accuracy is most important for the dosimetric investigation of AT2 in radioembolization, we recommend using the image subtraction method for this purpose.
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Affiliation(s)
- Camiel E M Kerckhaert
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands.
| | - Hugo W A M de Jong
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Marjolein B M Meddens
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Rob van Rooij
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Maarten L J Smits
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Yothin Rakvongthai
- Chulalongkorn University Biomedical Imaging Group, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
- Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Martijn M A Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
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Dietze MMA, de Jong HWAM. Progress in large field-of-view interventional planar scintigraphy and SPECT imaging. Expert Rev Med Devices 2022; 19:393-403. [PMID: 35695477 DOI: 10.1080/17434440.2022.2088355] [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: 11/04/2022]
Abstract
INTRODUCTION Handheld gamma cameras and gamma probes have been successfully implemented for enabling nuclear image or radio-guidance in minimally-invasive procedures. There is an opportunity for large field-of-view interventional planar scintigraphy and SPECT imaging to complement these small field-of-view devices for two reasons. First, a large field-of-view camera enables imaging of relatively larger organs and activity accumulations that are not close to the patient's skin. And second, more precise corrections can be implemented in the SPECT reconstruction algorithm, improving its quality. AREAS COVERED This review article discusses the progress that has been made in the field of large field-of-view interventional planar scintigraphy and SPECT imaging. First, an overview of planar scintigraphy and SPECT is provided. Second, an exploration is given of the potential applications where large field-of-view interventional planar scintigraphy and SPECT imaging may be employed. And third, the requirements for scanner hardware are discussed and an overview of the possible system configurations is provided. EXPERT OPINION We believe that there is an opportunity for large field-of-view interventional planar scintigraphy and SPECT imaging to assist clinical workflows. A major effort is now required to evaluate the prototype systems in clinical studies so that valuable practical experience can be obtained.
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Affiliation(s)
- Martijn M A Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center, Utrecht, Netherlands
| | - Hugo W A M de Jong
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center, Utrecht, Netherlands
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Keane G, Lam M, de Jong H. Beyond the MAA-Y90 Paradigm: The Evolution of Radioembolization Dosimetry Approaches and Scout Particles. Semin Intervent Radiol 2021; 38:542-553. [PMID: 34853500 DOI: 10.1055/s-0041-1736660] [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] [Indexed: 12/12/2022]
Abstract
Radioembolization is a well-established treatment for primary and metastatic liver cancer. There is increasing interest in personalized treatment planning supported by dosimetry, as it provides an opportunity to optimize dose delivery to tumor and minimize nontarget deposition, which demonstrably increases the efficacy and safety of this therapy. However, the optimal dosimetry procedure in the radioembolization setting is still evolving; existing data are limited as few trials have prospectively tailored dose based on personalized planning and predominantly semi-empirical methods are used for dose calculation. Since the pretreatment or "scout" procedure forms the basis of dosimetry calculations, an accurate and reliable technique is essential. 99m Tc-MAA SPECT constitutes the current accepted standard for pretreatment imaging; however, inconsistent patterns in published data raise the question whether this is the optimal agent. Alternative particles are now being introduced to the market, and early indications suggest use of an identical scout and treatment particle may be superior to the current standard. This review will undertake an evaluation of the increasingly refined dosimetric methods driving radioembolization practices, and a horizon scanning exercise identifying alternative scout particle solutions. Together these constitute a compelling vision for future treatment planning methods that prioritize individualized care.
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Affiliation(s)
- Grace Keane
- Nuclear Medicine, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
| | - Marnix Lam
- Nuclear Medicine, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
| | - Hugo de Jong
- Nuclear Medicine, Universitair Medisch Centrum Utrecht, Utrecht, The Netherlands
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Ichikawa H, Kawakami K, Onoguchi M, Shibutani T, Nagatake K, Hosoya T, Ito T, Kato T, Tsuchikame H, Shimada H. Automatic quantification package (Hone Graph) for phantom-based image quality assessment in bone SPECT: computerized automatic classification of detectability. Ann Nucl Med 2021; 35:937-946. [PMID: 34028702 DOI: 10.1007/s12149-021-01631-6] [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: 04/06/2021] [Accepted: 05/12/2021] [Indexed: 01/12/2023]
Abstract
OBJECTIVE We previously developed a custom-design thoracic bone scintigraphy-specific phantom ("SIM2 bone phantom") to assess image quality in bone single-photon emission computed tomography (SPECT). We aimed to develop an automatic assessment system for imaging technology in bone SPECT and demonstrate the validity of this system. METHODS Four spherical lesions of 13-, 17-, 22-, and 28-mm diameters in the vertebrae of SIM2 bone phantom simulating the thorax were filled with radioactivity (target-to-background ratio: 4). Dynamic SPECT acquisitions were performed for 15 min; reconstructions were performed using ordered subset expectation maximization at 3-15-min timepoints. Consequently, 216 lesions (54 SPECT images) were obtained: 120 and 96 lesions were used for software development and validation, respectively. The developed software used statistical parametric mapping to rigidly register and automatically calculate quantitative indexes (contrast-to-noise ratio, % coefficient of variance, % detectability equivalence volume, recovery coefficient, target-to-normal bone ratio, and full width at half maximum). A detectability score (DS) was used to define the four observation types (4, excellent; 3, adequate; 2, average; 1, poor) to score hot spherical lesions. The gold standard for DSs was independently classified by three experienced board-certified nuclear medicine technologists using the four observation types; thereafter, a consensus regarding the gold standard for DSs was reached. Using 120 lesions for development, decision tree analysis was performed to determine DS based on the quantitative indexes. We verified the validation of the quantitative indexes and their threshold values for automatic classification using 96 lesions for validation. RESULTS The trends in the automatically calculated quantitative indices were consistent. Decision tree analysis produced four terminal groups; two quantitative indexes (% detectability equivalence volume and contrast-to-noise ratio) were used to classify DS. The automatically classified DSs exhibited an almost perfect agreement with the gold standard. The percentage agreement and kappa coefficient were 91.7% and 0.93, respectively, in 96 lesions for validation. CONCLUSIONS The developed software automatically classified the detectability of hot lesions in the SIM2 bone phantom using the automatically calculated quantitative indexes, suggesting that this software could provide a means to automatically perform detectability analysis after data input that is excellent in reproducibility and accuracy.
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Affiliation(s)
- Hajime Ichikawa
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan
| | - Kazunori Kawakami
- Diagnostic Products Marketing Dept, FUJIFILM Toyama Chemical Co, Ltd. 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Masahisa Onoguchi
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan.
| | - Takayuki Shibutani
- Department of Quantum Medical Technology, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa, 9200942, Japan
| | - Kazuki Nagatake
- Quality Assurance Department, FUJIFILM Toyama Chemical Co., Ltd, 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Tetsuo Hosoya
- Quality Assurance Department, FUJIFILM Toyama Chemical Co., Ltd, 14-1, Kyobashi 2-Chome, Chuo-Ku, Tokyo, 1040031, Japan
| | - Toshimune Ito
- Department of Radiological Technology, Faculty of Medical Technology, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8605, Japan
| | - Toyohiro Kato
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
| | - Hirotatsu Tsuchikame
- Department of Radiology, Saiseikai Yokohamashi Tobu Hospital, Tsurumi Ward, 3-6-1 Shimosueyoshi, Yokohama, Kanagawa, 2300012, Japan
| | - Hideki Shimada
- Department of Radiology, Toyohashi Municipal Hospital, 50 Aza Hachiken Nishi, Aotake-Cho, Toyohashi, Aichi, 4418570, Japan
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Dietze MMA, Kunnen B, Brontsema F, Ramaekers P, Beijst C, Afifah M, Braat AJAT, Lam MGEH, de Jong HWAM. A compact and mobile hybrid C-arm scanner for simultaneous nuclear and fluoroscopic image guidance. Eur Radiol 2021; 32:517-523. [PMID: 34132877 PMCID: PMC8660732 DOI: 10.1007/s00330-021-08023-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/22/2021] [Accepted: 04/27/2021] [Indexed: 11/24/2022]
Abstract
Purpose This study evaluates the performance of a mobile and compact hybrid C-arm scanner (referred to as IXSI) that is capable of simultaneous acquisition of 2D fluoroscopic and nuclear projections and 3D image reconstruction in the intervention room. Results The impact of slightly misaligning the IXSI modalities (in an off-focus geometry) was investigated for the reduction of the fluoroscopic and nuclear interference. The 2D and 3D nuclear image quality of IXSI was compared with a clinical SPECT/CT scanner by determining the spatial resolution and sensitivity of point sources and by performing a quantitative analysis of the reconstructed NEMA image quality phantom. The 2D and 3D fluoroscopic image of IXSI was compared with a clinical CBCT scanner by visualizing the Fluorad A+D image quality phantom and by visualizing a reconstructed liver nodule phantom. Finally, the feasibility of dynamic simultaneous nuclear and fluoroscopic imaging was demonstrated by injecting an anthropomorphic phantom with a mixture of iodinated contrast and 99mTc. Conclusion Due to the divergent innovative hybrid design of IXSI, concessions were made to the nuclear and fluoroscopic image qualities. Nevertheless, IXSI realizes unique image guidance that may be beneficial for several types of procedures. Key Points • IXSI can perform time-resolved planar (2D) simultaneous fluoroscopic and nuclear imaging. • IXSI can perform SPECT/CBCT imaging (3D) inside the intervention room. Supplementary Information The online version contains supplementary material available at 10.1007/s00330-021-08023-4.
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Affiliation(s)
- Martijn M A Dietze
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands. .,Image Sciences Institute, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.
| | - Britt Kunnen
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.,Image Sciences Institute, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Frank Brontsema
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Pascal Ramaekers
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Casper Beijst
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Maryam Afifah
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Arthur J A T Braat
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Marnix G E H Lam
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
| | - Hugo W A M de Jong
- Radiology and Nuclear Medicine, University Medical Center Utrecht and Utrecht University, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands
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Dietze MMA, Kunnen B, Lam MGEH, de Jong HWAM. Interventional respiratory motion compensation by simultaneous fluoroscopic and nuclear imaging: a phantom study. Phys Med Biol 2021; 66:065001. [PMID: 33571969 DOI: 10.1088/1361-6560/abe556] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE A compact and mobile hybrid c-arm scanner, capable of simultaneously acquiring nuclear and fluoroscopic projections and SPECT/CBCT, was developed to aid fluoroscopy-guided interventional procedures involving the administration of radionuclides (e.g. hepatic radioembolization). However, as in conventional SPECT/CT, the acquired nuclear images may be deteriorated by patient respiratory motion. We propose to perform compensation for respiratory motion by extracting the motion signal from fluoroscopic projections so that the nuclear counts can be gated into motion bins. The purpose of this study is to quantify the performance of this motion compensation technique with phantom experiments. METHODS Anthropomorphic phantom configurations that are representative of distributions obtained during the pre-treatment procedure of hepatic radioembolization were placed on a stage that translated with three different motion patterns. Fluoroscopic projections and nuclear counts were simultaneously acquired under planar and SPECT/CBCT imaging. The planar projections were visually assessed. The SPECT reconstructions were visually assessed and quantitatively assessed by calculating the activity recovery of the spherical inserts in the phantom. RESULTS The planar nuclear projections of the translating anthropomorphic phantom were blurry when no motion compensation was applied. With motion compensation, the nuclear projections became representative of the stationary phantom nuclear projection. Similar behavior was observed for the visual quality of SPECT reconstructions. The mean error of the activity recovery in the uncompensated SPECT reconstructions was 15.8% ± 0.9% for stable motion, 11.9% ± 0.9% for small variations, and 11.0% ± 0.9% for large variations. When applying motion compensation, the mean error decreased to 1.8% ± 1.6% for stable motion, 2.2% ± 1.5% for small variations, and 5.2% ± 2.5% for large variations. CONCLUSION A compact and mobile hybrid c-arm scanner, capable of simultaneously acquiring nuclear and fluoroscopic projections, can perform compensation for respiratory motion. Such motion compensation results in sharper planar nuclear projections and increases the quantitative accuracy of the SPECT reconstructions.
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Affiliation(s)
- Martijn M A Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands. Image Sciences Institute, Utrecht University and University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands
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Dietze MMA, Koppert WJC, van Rooij R, de Jong HWAM. Technical Note: Nuclear imaging with an x-ray flat panel detector: A proof-of-concept study. Med Phys 2020; 47:3363-3368. [PMID: 32314368 PMCID: PMC7496965 DOI: 10.1002/mp.14191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 03/17/2020] [Accepted: 04/15/2020] [Indexed: 12/27/2022] Open
Abstract
PURPOSE Interventional procedures involving radionuclides (e.g., radioembolization) would benefit from single-photon emission computed tomography (SPECT) performed in the intervention room because the activity distribution could be immediately visualized. We believe it might be possible to perform SPECT with the C-arm cone beam computed tomography (CBCT) scanner present in the intervention room by equipping the x-ray flat panel detector with a collimator. The purpose of this study is to demonstrate the approach and to investigate the achievable SPECT reconstruction quality. METHODS A proof-of-concept experiment was performed to evaluate the possibility of nuclear imaging with an x-ray flat panel detector. The experiment was digitally replicated to study the accuracy of the simulations. Three flat panel configurations (with standard hardware and reconstruction methodology, with sophisticated reconstruction methodology, and with expected future hardware) and a conventional gamma camera were evaluated. The Jaszczak and the NEMA IQ phantom (filled with 99m Tc) were simulated and assessed on resolution and contrast-to-noise ratio (CNR). RESULTS The proof-of-concept experiment demonstrated that nuclear images could be obtained from the flat panel detector. The simulation of the same configuration demonstrated that simulations could accurately predict the flat panel detector response. The CNR of the 37 mm sphere in the NEMA IQ phantom was 22.8 ± 1.2 for the gamma camera reconstructions, while it was 11.3 ± 0.7 for the standard flat panel detector. With sophisticated reconstruction methodology, the CNR improved to 13.5 ± 1.4. The CNR can be expected to advance to 18.1 ± 1.3 for future flat panel detectors. CONCLUSIONS The x-ray flat panel detector of a CBCT scanner might be used to perform nuclear imaging. The SPECT reconstruction quality will be lower than that achieved by a conventional gamma camera. The flat panel detector approach could, however, be useful in providing a cost-effective alternative to the purchase of a mobile SPECT scanner for enabling interventional scanning.
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Affiliation(s)
- Martijn M A Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands.,Image Sciences Institute, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Wilco J C Koppert
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Rob van Rooij
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
| | - Hugo W A M de Jong
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, Netherlands
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Dietze MMA, Kunnen B, Beijst C, de Jong HWAM. Adaptive scan duration in SPECT: Evaluation for radioembolization. Med Phys 2020; 47:2128-2138. [PMID: 32060928 PMCID: PMC7317548 DOI: 10.1002/mp.14095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/12/2020] [Accepted: 02/12/2020] [Indexed: 12/14/2022] Open
Abstract
PURPOSE It may be challenging to select the optimal scan duration for single-photon emission computed tomography (SPECT) protocols because the activity distribution characteristics can differ in every scan. Using simulations and experiments, we investigated whether the scan duration can be optimized for every scan separately by evaluating the activity distribution during scanning. We refer to this as adaptive scanning. METHODS The feasibility of adaptive scanning was evaluated for the detection of extrahepatic depositions in the pretreatment procedure of radioembolization, in which 99m Tc-labeled macroaggregated albumin (99m Tc-MAA) is injected into the liver. We simulated fast 1-min detector rotations and updated the reconstruction with the newly collected counts after every rotation. The scan was terminated when one of the two criteria was met: (a) when the mask difference of the detected extrahepatic deposition between two consecutive rotations was lower than 5%; or (b) when the reconstructed extrahepatic activity was negligible with respect to the total reconstructed activity (<0.075%). The performance of adaptive scanning was evaluated using a digital phantom with various activity distributions, a physical phantom experiment, and simulations based on 129 patient activity distributions. RESULTS The digital phantom data showed that the scan termination times substantially depended on the activity distribution characteristics. The experimental phantom data showed the feasibility of adaptive scanning with physical scanner measurements and illustrated that fast detector motion was not limiting the adaptive scanning performance. The patient data showed a large spread in the scan terminations times. By adaptive scanning, the mean scan duration of the patient distributions was shortened from 20 min (current clinical protocol) to 4.8 ± 0.2 min. The detection accuracy of extrahepatic depositions was unaffected and the mean difference in the extrahepatic deposition masks (compared with the 20-min scan) was only 7.0 ± 1.0%. CONCLUSION Our study suggests that the SPECT scan duration can be personalized by assessing the activity distribution characteristics during scanning for the detection of extrahepatic depositions in the pretreatment procedure of radioembolization. The adaptive scanning approach might also be of benefit for other SPECT protocols, as long as a measure of interest is available for optimization.
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Affiliation(s)
- Martijn M A Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Britt Kunnen
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Casper Beijst
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands
| | - Hugo W A M de Jong
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands.,Image Sciences Institute, Utrecht University and University Medical Center Utrecht, Utrecht, the Netherlands
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Dietze MMA, Bastiaannet R, Kunnen B, van der Velden S, Lam MGEH, Viergever MA, de Jong HWAM. Respiratory motion compensation in interventional liver SPECT using simultaneous fluoroscopic and nuclear imaging. Med Phys 2019; 46:3496-3507. [PMID: 31183868 PMCID: PMC6851796 DOI: 10.1002/mp.13653] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 01/22/2023] Open
Abstract
PURPOSE Quantitative accuracy of the single photon emission computed tomography (SPECT) reconstruction of the pretreatment procedure of liver radioembolization is crucial for dosimetry; visual quality is important for detecting doses deposited outside the planned treatment volume. Quantitative accuracy is limited by respiratory motion. Conventional gating eliminates motion by count rejection but increases noise, which degrades the visual reconstruction quality. Motion compensation using all counts can be performed if the motion signal and motion vector field over time are known. The measurement of the motion signal of a patient currently requires a device (such as a respiratory belt) attached to the patient, which complicates the acquisition. The motion vector field is generally extracted from a previously acquired four-dimensional scan and can differ from the motion in the scan performed during the intervention. The simultaneous acquisition of fluoroscopic and nuclear projections can be used to obtain both the motion vector field and the projections of the corresponding (moving) activity distribution. This eliminates the need for devices attached to the patient and provides an accurate motion vector field for SPECT reconstruction. Our approach to motion compensation would primarily be beneficial for interventional SPECT because the time-critical setting requires fast scans and no inconvenience of an external apparatus. The purpose of this work is to evaluate the performance of the motion compensation approach for interventional liver SPECT by means of simulations. METHODS Nuclear and fluoroscopic projections of a realistic digital human phantom with respiratory motion were generated using fast Monte Carlo simulators. Fluoroscopic projections were sampled at 1-5 Hz. Nuclear data were acquired continuously in list mode. The motion signal was extracted from the fluoroscopic projections by calculating the center-of-mass, which was then used to assign each photon to a corresponding motion bin. The fluoroscopic projections were reconstructed per bin and coregistered, resulting in a motion vector field that was used in the SPECT reconstruction. The influence of breathing patterns, fluoroscopic imaging dose, sampling rate, number of bins, and scanning time was studied. In addition, the motion compensation method was compared with conventional gating to evaluate the detectability of spheres with varying uptake ratios. RESULTS The liver motion signal was accurately extracted from the fluoroscopic projections, provided the motion was stable in amplitude and the sampling rate was greater than 2 Hz. The minimum total fluoroscopic dose for the proposed method to function in a 5-min scan was 10 µGy. Although conventional gating improved the quantitative reconstruction accuracy, substantial background noise was observed in the short scans because of the limited counts available. The proposed method similarly improved the quantitative accuracy, but generated reconstructions with higher visual quality. The proposed method provided better visualization of low-contrast features than when using gating. CONCLUSION The proposed motion compensation method has the potential to improve SPECT reconstruction quality. The method eliminates the need for external devices to measure the motion signal and generates an accurate motion vector field for reconstruction. A minimal increase in the fluoroscopic dose is required to substantially improve the results, paving the way for clinical use.
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Affiliation(s)
- Martijn M. A. Dietze
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Remco Bastiaannet
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Britt Kunnen
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Sandra van der Velden
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Marnix G. E. H. Lam
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Max A. Viergever
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
| | - Hugo W. A. M. de Jong
- Radiology and Nuclear MedicineUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
- Image Sciences InstituteUtrecht University and University Medical Center UtrechtP.O. Box 855003508 GAUtrechtthe Netherlands
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Dietze MMA, Branderhorst W, Kunnen B, Viergever MA, de Jong HWAM. Accelerated SPECT image reconstruction with FBP and an image enhancement convolutional neural network. EJNMMI Phys 2019; 6:14. [PMID: 31359208 PMCID: PMC6663955 DOI: 10.1186/s40658-019-0252-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 07/24/2019] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Monte Carlo-based iterative reconstruction to correct for photon scatter and collimator effects has been proven to be superior over analytical correction schemes in single-photon emission computed tomography (SPECT/CT), but it is currently not commonly used in daily clinical practice due to the long associated reconstruction times. We propose to use a convolutional neural network (CNN) to upgrade fast filtered back projection (FBP) image quality so that reconstructions comparable in quality to the Monte Carlo-based reconstruction can be obtained within seconds. RESULTS A total of 128 technetium-99m macroaggregated albumin pre-treatment SPECT/CT scans used to guide hepatic radioembolization were available. Four reconstruction methods were compared: FBP, clinical reconstruction, Monte Carlo-based reconstruction, and the neural network approach. The CNN generated reconstructions in 5 sec, whereas clinical reconstruction took 5 min and the Monte Carlo-based reconstruction took 19 min. The mean squared error of the neural network approach in the validation set was between that of the Monte Carlo-based and clinical reconstruction, and the lung shunting fraction difference was lower than 2 percent point. A phantom experiment showed that quantitative measures required in radioembolization were accurately retrieved from the CNN-generated reconstructions. CONCLUSIONS FBP with an image enhancement neural network provides SPECT reconstructions with quality close to that obtained with Monte Carlo-based reconstruction within seconds.
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Affiliation(s)
- Martijn M. A. Dietze
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
- Image Sciences Institute, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
| | - Woutjan Branderhorst
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
| | - Britt Kunnen
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
- Image Sciences Institute, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
| | - Max A. Viergever
- Image Sciences Institute, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
| | - Hugo W. A. M. de Jong
- Radiology and Nuclear Medicine, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
- Image Sciences Institute, Utrecht University and University Medical Center Utrecht, P.O. Box 85500, 3508 Utrecht, GA Netherlands
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Koppert WJC, Dietze MMA, van der Velden S, Steenbergen JHL, de Jong HWAM. A comparative study of NaI(Tl), CeBr3, and CZT for use in a real-time simultaneous nuclear and fluoroscopic dual-layer detector. ACTA ACUST UNITED AC 2019; 64:135012. [DOI: 10.1088/1361-6560/ab267c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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