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Morphis M, van Staden JA, du Raan H, Ljungberg M. Evaluation of Iodine-123 and Iodine-131 SPECT activity quantification: a Monte Carlo study. EJNMMI Phys 2021; 8:61. [PMID: 34410539 PMCID: PMC8377107 DOI: 10.1186/s40658-021-00407-1] [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: 05/21/2021] [Accepted: 08/10/2021] [Indexed: 01/18/2023] Open
Abstract
Purpose The quantitative accuracy of Nuclear Medicine images, acquired for both planar and SPECT studies, is influenced by the isotope-collimator combination as well as image corrections incorporated in the iterative reconstruction process. These factors can be investigated and optimised using Monte Carlo simulations. This study aimed to evaluate SPECT quantification accuracy for 123I with both the low-energy high resolution (LEHR) and medium-energy (ME) collimators and 131I with the high-energy (HE) collimator. Methods Simulated SPECT projection images were reconstructed using the OS-EM iterative algorithm, which was optimised for the number of updates, with appropriate corrections for scatter, attenuation and collimator detector response (CDR), including septal scatter and penetration compensation. An appropriate calibration factor (CF) was determined from four different source geometries (activity-filled: water-filled cylindrical phantom, sphere in water-filled (cold) cylindrical phantom, sphere in air and point-like source), investigated with different volume of interest (VOI) diameters. Recovery curves were constructed from recovery coefficients to correct for partial volume effects (PVEs). The quantitative method was evaluated for spheres in voxel-based digital cylindrical and patient phantoms. Results The optimal number of OS-EM updates was 60 for all isotope-collimator combinations. The CFpoint with a VOI diameter equal to the physical size plus a 3.0-cm margin was selected, for all isotope-collimator geometries. The spheres’ quantification errors in the voxel-based digital cylindrical and patient phantoms were less than 3.2% and 5.4%, respectively, for all isotope-collimator combinations. Conclusion The study showed that quantification errors of less than 6.0% could be attained, for all isotope-collimator combinations, if corrections for; scatter, attenuation, CDR (including septal scatter and penetration) and PVEs are performed. 123I LEHR and 123I ME quantification accuracies compared well when appropriate corrections for septal scatter and penetration were applied. This can be useful in departments that perform 123I studies and may not have access to ME collimators.
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Affiliation(s)
- Michaella Morphis
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa.
| | - Johan A van Staden
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
| | - Hanlie du Raan
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
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Verschure DO, Poel E, Nakajima K, Okuda K, van Eck-Smit BLF, Somsen GA, Verberne HJ. A European myocardial 123I-mIBG cross-calibration phantom study. J Nucl Cardiol 2018; 25:1191-1197. [PMID: 28120154 PMCID: PMC6133137 DOI: 10.1007/s12350-017-0782-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 12/30/2016] [Indexed: 11/30/2022]
Abstract
AIM Planar myocardial 123I-meta-iodobenzylguanidine (123I-mIBG) scintigraphy is a highly reproducible technique. However, differences in collimator use are one of the most important factors that cause variation among institutions and studies in heart-to-mediastinum (H/M) ratio. Therefore, standardization among various gamma camera-collimator combinations is needed. Previously, a phantom has been developed to cross-calibrate different acquisition conditions in Japan. For further cross-calibration of European myocardial 123I-mIBG imaging, the aim of this study was to collect 123I-mIBG data for H/M ratios from common European gamma camera vendors. METHODS 210 experiments were performed in 27 European institutions. Based on these experiments, conversion coefficients for each gamma camera-collimator combination were calculated. An averaged conversion coefficient of 0.88 was used to calculate a standardized H/M ratio. RESULTS On average, LE-collimator-derived H/M ratios were significantly lower compared to ME-collimator-derived H/M ratios. The mean conversion coefficients ranged from 0.553 to 0.605 for the LE-collimator group and from 0.824 to 0.895 for the ME-collimator group. CONCLUSION Clinically established H/M ratios can be converted into standardized H/M ratios using cross-calibrated conversion coefficients. This standardization is important for identifying appropriate thresholds for adequate risk stratification. In addition, this cross-calibration enables comparison between different national and international data.
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Affiliation(s)
- Derk O Verschure
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands.
- Department of Cardiology, Zaans Medical Center, Zaandam, The Netherlands.
| | - Edwin Poel
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - Kenichi Nakajima
- Department of Nuclear Medicine, Kanazawa University Hospital, Kanazawa, Japan
| | - Koichi Okuda
- Department of Physics, Kanazawa Medical University, Uchinada, Japan
| | - Berthe L F van Eck-Smit
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
| | - G Aernout Somsen
- Cardiology Centers of the Netherlands, Amsterdam, The Netherlands
| | - Hein J Verberne
- Department of Nuclear Medicine, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE, Amsterdam, The Netherlands
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Inoue Y, Abe Y, Kikuchi K, Matsunaga K, Masuda R, Nishiyama K. Correction of collimator-dependent differences in the heart-to-mediastinum ratio in 123I-metaiodobenzylguanidine cardiac sympathetic imaging: Determination of conversion equations using point-source imaging. J Nucl Cardiol 2017; 24:1725-1736. [PMID: 27251143 PMCID: PMC5629249 DOI: 10.1007/s12350-016-0546-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 05/04/2016] [Indexed: 12/11/2022]
Abstract
BACKGROUND Septal penetration causes collimator-dependent differences in the heart-to-mediastinum (H/M) ratio in 123I-metaiodobenzylguanidine (MIBG) cardiac imaging. We investigated generally applicable methods to correct such differences. METHODS AND RESULTS Four hours after 123I-MIBG injection, 40 patients underwent anterior chest imaging successively with medium-energy (ME) and various non-ME collimators. The H/M ratios obtained with the non-ME collimators before and after 123I-dual-window penetration correction were compared with the ME-derived standard values to determine patient-based conversion equations for empiric and combined corrections, respectively. A 123I point source was imaged with various collimators, and the central ratio, the ratio of count in a small central region of interest to count in a large one, was calculated. The method of predicting the conversion equations from the central ratios was determined. Correction using the patient-based conversion equations removed systematic underestimation of the H/M ratios obtained with the non-ME collimators, and combined correction depressed residual random errors to some degree. Point-source-based equations yielded results comparable to the patient-based equations. CONCLUSIONS Empiric and combined corrections effectively reduce collimator-dependent differences in the H/M ratio. The conversion equations can be predicted from simple point-source imaging, which would allow to apply these corrections to data obtained with various collimators.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, 1-15-1 Kitasato Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan.
| | - Yutaka Abe
- Department of Radiology, Kitasato University Hospital, Sagamihara, Japan
| | - Kei Kikuchi
- Department of Radiology, Kitasato University Hospital, Sagamihara, Japan
| | - Keiji Matsunaga
- Department of Diagnostic Radiology, Kitasato University School of Medicine, 1-15-1 Kitasato Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Ray Masuda
- Department of Neurology, Kitasato University School of Medicine, Sagamihara, Japan
| | - Kazutoshi Nishiyama
- Department of Neurology, Kitasato University School of Medicine, Sagamihara, Japan
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Inoue Y, Abe Y, Asano Y, Kikuchi K. Validity of the mediastinum as a reference region to evaluate cardiac accumulation of iodine-123 metaiodobenzylguanidine. Ann Nucl Med 2015; 29:650-7. [DOI: 10.1007/s12149-015-0989-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 05/18/2015] [Indexed: 11/29/2022]
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123I-MIBG Cardiac Imaging: Acquisition Protocols and Correction Methods for Quantitative Evaluation. CURRENT CARDIOVASCULAR IMAGING REPORTS 2015. [DOI: 10.1007/s12410-014-9306-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Inoue Y, Abe Y, Asano Y, Kikuchi K, Matsunaga K, Iizuka T, Nishiyama K. An improved method for estimating the heart-to-mediastinum ratio from cardiac sympathetic nerve imaging with low-energy high-resolution collimators. J Nucl Cardiol 2014; 21:614-21. [PMID: 24715623 DOI: 10.1007/s12350-014-9893-5] [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] [Received: 02/09/2014] [Accepted: 03/10/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Septal penetration causes underestimation of the heart-to-mediastinum (H/M) ratio in cardiac (123)I-metaiodobenzylguanidine (MIBG) imaging with a low-energy high-resolution (LEHR) collimator. We aimed to improve the method of estimating the H/M ratios using the LEHR collimator. METHODS AND RESULTS 4 hours after (123)I-MIBG injection, 40 patients were imaged successively with the medium-energy (ME) and LEHR collimators using gamma cameras having 3/8-inch crystals. Severe underestimation of the H/M ratios was observed with the LEHR collimator when compared to the ME collimator. Narrowing the energy window width did not reduce the underestimation. Application of (123)I-dual-window (IDW) correction using a narrow or wide subwindow reduced the underestimation substantially but not entirely. The H/M ratios estimated from the LEHR images with or without IDW correction were corrected based on their correlations with the ratios estimated from the ME images. This empiric correction removed systematic underestimation, and residual errors were reduced when the H/M ratios after IDW correction were converted using the empiric equation. The conversion equation was successfully applied to the correction of the H/M ratios determined in another 40 patients using a 5/8-inch crystal. CONCLUSIONS In estimating the H/M ratios using an LEHR collimator, empiric correction combined with IDW correction improves concordance with ME-based values in comparison with empiric correction alone.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan,
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Inoue Y, Abe Y, Asano Y, Kikuchi K, Iizuka T, Nishiyama K. Septal penetration in iodine-123 metaiodobenzylguanidine cardiac sympathetic imaging using a medium-energy collimator. J Nucl Cardiol 2014; 21:71-7. [PMID: 24150537 DOI: 10.1007/s12350-013-9804-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/03/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Septal penetration of high-energy photons affects the estimation of the heart-to-mediastinum (H/M) ratio in cardiac (123)I-metaiodobenzylguanidine (MIBG) imaging, and the use of a medium-energy (ME) collimator has been shown to improve quantitative accuracy. We investigated the effect of septal penetration on the estimation of H/M ratios using an ME collimator. METHODS AND RESULTS Point sources of (99m)Tc and (123)I were imaged using various collimators, which indicated that the effect of high-energy photons with the ME collimator was relatively small but larger than that with the high-energy (HE) collimator. Four hours after (123)I-MIBG injection, 20 patients underwent planar anterior chest imaging by different methods in succession. The ME collimator gave lower H/M ratios (mean 2.52) than the HE collimator (2.57), indicating influence of septal penetration in the ME collimator; however, the difference was limited. Although narrowing the energy window from 20% (2.51) to 15% (2.54) increased the H/M ratios in imaging with the ME collimator, the difference was quite limited. CONCLUSIONS Septal penetration affects the estimation of the H/M ratios using an ME collimator; however, this influence is small and would not have clinical significance.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan,
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Inoue Y, Abe Y, Itoh Y, Asano Y, Kikuchi K, Sakamoto Y, Matsunaga K, Ogino Y, Iizuka T, Mochizuki H. Acquisition protocols and correction methods for estimation of the heart-to-mediastinum ratio in 123I-metaiodobenzylguanidine cardiac sympathetic imaging. J Nucl Med 2013; 54:707-13. [PMID: 23536225 DOI: 10.2967/jnumed.112.111955] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED Septal penetration of high-energy photons affects quantitative results in imaging of (123)I-labeled tracers. We investigated acquisition protocols (collimator choice and energy window setting) and correction methods for estimating the heart-to-mediastinum (H/M) ratio in cardiac (123)I-metaiodobenzylguanidine (MIBG) imaging. METHODS Four hours after (123)I-MIBG injection, 40 patients successively underwent planar anterior chest imaging with the medium-energy (ME) (ME method) and low-energy high-resolution (LEHR) (LEHR method) collimators. A 20% energy window was used for both collimators. Another 40 patients were imaged successively with the ME collimator and a 20% window (ME method), the low-medium-energy (LME) collimator and a 20% window (LME20 method), and the LME collimator and a 15% window (LME15 method). The H/M ratios obtained by the LEHR, LME20, and LME15 methods were corrected using their correlations with the H/M ratio obtained by the ME method (empiric correction). The (123)I-dual-window (IDW) correction was also applied to remove the influence of high-energy photons. RESULTS Without correction, severe underestimation of the H/M ratio was shown for the LEHR method using the ME method as a standard, and this underestimation increased with increasing H/M ratios. Underestimation substantially decreased using the LME20 method and further using the LME15 method. Empiric correction reduced the error in the H/M ratio by the LEHR method, but the error was still evident. After empiric correction, the H/M ratios with the LME collimator were comparable to those with the ME collimator. The IDW correction only partially reduced underestimation by the LEHR method and caused a small overestimation for the LME15 method. CONCLUSION The use of an LME collimator appears to be acceptable for cardiac (123)I-MIBG imaging as an alternative to an ME collimator, and the application of a 15% energy window is recommended when an LME collimator is used. Empiric correction is also expected to improve exchangeability between H/M ratios calculated with ME and LME collimators. Neither the use of an LEHR collimator nor the use of IDW correction is recommended.
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Affiliation(s)
- Yusuke Inoue
- Department of Diagnostic Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan.
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Calibration of gamma camera systems for a multicentre European 123I-FP-CIT SPECT normal database. Eur J Nucl Med Mol Imaging 2011; 38:1529-40. [DOI: 10.1007/s00259-011-1801-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
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Morton RJ, Guy MJ, Clauss R, Hinton PJ, Marshall CA, Clarke EA. Comparison of different methods of DatSCAN quantification. Nucl Med Commun 2005; 26:1139-46. [PMID: 16264363 DOI: 10.1097/00006231-200512000-00015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The quantification of DaTSCAN images can be used as an adjunct to visual assessment to differentiate between Parkinson's syndrome and essential tremor. Many programs have been written to assess the relative uptake in the striatum. AIM To compare two of the commercially available programs: QuantiSPECT, which analyses isolated data in two dimensions, and BRASS, which performs three-dimensional processing referencing a normal image template. METHOD Twenty-two patients (11 with Parkinson's syndrome and 11 with essential tremor) were visually assessed by two nuclear medicine consultants. The patient data were then processed using two commercial programs to determine the relative uptake in the striatum. A comparison of the results from the programs was performed, together with a comparison with the visual assessment. The inter-operator and intra-operator variabilities were also ascertained. RESULTS All programs and processing methods could distinguish between Parkinson's syndrome and essential tremor. There was also a good correlation between the results from the three- and two-dimensional methods. The intra-operator and inter-operator variabilities were dependent on the amount of operator intervention. CONCLUSION Both programs allowed statistical differentiation between Parkinson's syndrome and essential tremor. Strict operator protocols are needed with QuantiSPECT to reduce inter- and intra-operator variation. The three-dimensional method (BRASS) gave greater concordance than the two-dimensional method (QuantiSPECT) with the visual assessment, but at a cost of increased operator time.
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Affiliation(s)
- Rosemary J Morton
- Department of Nuclear Medicine, Royal Surrey County Hospital, Guildford, Surrey, UK.
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Morton RJ, Guy MJ, Marshall CA, Clarke EA, Hinton PJ. Variation of DaTSCAN quantification between different gamma camera types. Nucl Med Commun 2005; 26:1131-7. [PMID: 16264362 DOI: 10.1097/00006231-200512000-00014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To acquire data from a 123I filled Alderson phantom on different gamma cameras types and compare the relative uptake results from processing using the QuantiSPECT program (GE Healthcare). METHODS A DaTSCAN phantom was filled using the standard protocol and imaged on seven different gamma camera types and on two identical cameras of the same type. The standard GE Healthcare protocols for the given cameras were used. Aliquots of the striatum and brain background were counted in a gamma counter to determine variations in filling concentration. All the raw DaTSCAN SPECT data was imported into QuantiSPECT and processed by the three different algorithms (two box, three box and crescent) to determine the relative uptake in the striatum. Inter-operater and intra-operator variation was also determined. RESULTS The 10% variation in filling concentration found across the sites was compensated for in the final results. There was a 5-15% variation between cameras depending on the processing algorithm used. There was an intra-operator variation of between 5 and 12% which reflected the proportion of operator intervention within the processing method. There was no statistical variation between operators. CONCLUSIONS The transfer of a DaTSCAN database between camera types is feasible, but ideally all data would be acquired on a single camera type and phantom data used to normalize the database accordingly.
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Affiliation(s)
- Rosemary J Morton
- Department of Nuclear Medicine, Royal Surrey County Hospital, Guildford, Surrey, UK.
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Dontu VS, Kettle AG, O'Doherty MJ, Coakley AJ. Optimization of parathyroid imaging by simultaneous dual energy planar and single photon emission tomography. Nucl Med Commun 2005; 25:1089-93. [PMID: 15577586 DOI: 10.1097/00006231-200411000-00004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Single photon emission tomography (SPET) gives valuable 3-dimensional information, but prolongs the time of imaging and increases the possibility of patient movement. We therefore investigated a method for the optimization of SPET. METHOD Using an in-house fabricated thyroid/parathyroid neck phantom simultaneous dual energy (DE) 1223I/99mTc imaging to localize parathyroid glands was assessed both in planar and SPET modes. RESULTS Experiments demonstrated improved spatial resolution and contrast for planar pinhole imaging compared to parallel collimation. For DE-SPET compared to planar pinhole imaging more glands in the phantom were visualized by the improved contrast. CONCLUSION We conclude that DE-SPET for parathyroid imaging is feasible to aid the accurate localization of parathyroid adenomas. For planar imaging pinhole collimation is superior to parallel hole collimation.
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Affiliation(s)
- Vijay S Dontu
- Nuclear Medicine Department, Kent & Canterbury Hospital, East Kent Hospitals NHS Trust, Ethelbert Road, Canterbury CT1 3NG, Kent, UK.
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Inoue Y, Shirouzu I, Machida T, Yoshizawa Y, Akita F, Minami M, Ohtomo K. Collimator choice in cardiac SPECT with I-123-labeled tracers. J Nucl Cardiol 2004; 11:433-9. [PMID: 15295412 DOI: 10.1016/j.nuclcard.2004.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND Septal penetration of high-energy photons may degrade the quality of single photon emission computed tomography (SPECT) of the heart with iodine 123-labeled tracers. We investigated the impact of collimator choice on cardiac SPECT with I-123. METHODS AND RESULTS SPECT of a thoracic phantom containing I-123 solution was performed with a low-energy high-resolution (LEHR) collimator, special LEHR (SLEHR) collimator, and medium-energy (ME) collimator, and the cavity-to-myocardium contrast, wall thickness, and defect contrast were compared among the collimators. For all indices, use of the SLEHR collimator yielded the best results. Comparison between the LEHR and ME collimators revealed that the cavity-to-myocardium contrast and contrast for large defects were better with the ME collimator, whereas wall thickness and contrast for small defects were similar. Scatter correction by the triple-energy window method improved the indices examined; however, the superiority of the SLEHR collimator was still observed after correction. CONCLUSIONS Collimator choice substantially influences the quality of cardiac SPECT with I-123-labeled agents, and an appropriate collimator needs to be selected in consideration of septal penetration and spatial resolution.
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Affiliation(s)
- Yusuke Inoue
- Department of Radiology, Institute of Medical Science, University of Tokyo, Japan.
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