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Mourik JEM, Derks M, Te Beek ET, Ten Broek MRJ. Gamma camera-specific reference standards for radioactive iodine uptake measurements. EJNMMI Phys 2023; 10:55. [PMID: 37702889 PMCID: PMC10499732 DOI: 10.1186/s40658-023-00575-2] [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: 01/31/2023] [Accepted: 09/05/2023] [Indexed: 09/14/2023] Open
Abstract
BACKGROUND Current guidelines of the radioiodine uptake (RAIU) test allow the use of different equipment, isotopes, activity and region-of-interest (ROI). We evaluated presence and extent of these differences in clinical practice and evaluated the effect of some of these variations on RAIU outcomes. Also, gamma camera-specific reference standards were calculated and retrospectively compared with measurements obtained during clinical RAIU tests. MATERIALS AND METHODS First, questionnaires were sent to Dutch nuclear medicine departments requesting information about equipment usage, isotope, isotope formulation, activity and measurement techniques. Secondly, a neck phantom containing a range of activities in capsule or water-dissolved formulation was scanned. Counts were measured using automatic ROI, square box ROI or all counts in the image. Thirdly, clinical RAIU data were collected during 2015-2018 using three different gamma cameras. Reference standards for each scanner were calculated using regression analysis between reference activity and measured counts. Uptake measurements using this gamma camera-specific reference standard were compared with original measurements. RESULTS The survey demonstrated significant differences in isotope, isotope formulation, activity, use of neck phantoms, frequency and duration of reference measurements, distance to collimator, use of background measurements and ROI delineation. The phantom study demonstrated higher counts for the water-dissolved formulation than capsules using both automatic and square box ROI. Also, higher counts were found using a square box ROI than an automatic ROI. The retrospective study showed feasibility of RAIU calculations using camera-specific reference standards and good correlation with the original RAIU measurements. CONCLUSIONS This study demonstrated considerable technical variation in RAIU measurement in clinical practice. The phantom study demonstrated that these differences could result in differences in count measurements, potentially resulting in different dose calculations for radioactive iodine therapy. Retrospective data suggest that camera-specific reference standards may be used instead of individual reference measurements using separate activity sources, which may thus eliminate some sources of variation.
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Affiliation(s)
- Jurgen E M Mourik
- Department of Nuclear Medicine, Franciscus Gasthuis & Vlietland Hospital, Kleiweg 500, 3045 PM, Rotterdam, The Netherlands.
| | - Mark Derks
- Department of Nuclear Medicine, IJsselland Hospital, Capelle aan den IJssel, The Netherlands
| | - Erik T Te Beek
- Department of Nuclear Medicine, Reinier de Graaf Hospital, Delft, The Netherlands
| | - Marc R J Ten Broek
- Department of Nuclear Medicine, IJsselland Hospital, Capelle aan den IJssel, The Netherlands
- Department of Nuclear Medicine, Reinier de Graaf Hospital, Delft, The Netherlands
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Nagy F, Krizsan AK, Kukuts K, Szolikova M, Hascsi Z, Barna S, Acs A, Szabo P, Tron L, Balkay L, Dahlbom M, Zentai M, Forgacs A, Garai I. Q-Bot: automatic DICOM metadata monitoring for the next level of quality management in nuclear medicine. EJNMMI Phys 2021; 8:28. [PMID: 33738627 PMCID: PMC7973342 DOI: 10.1186/s40658-021-00371-w] [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: 07/31/2020] [Accepted: 02/23/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Regular and precise inspection of the realization of the local nuclear medicine standard operation procedures (SOPs) is very complex and time-consuming, especially when large amount of patient data is obtained from a wide scale of different scan procedures on a daily basis. DICOM metadata comprise a complete set of data related to the patient and the imaging procedure, and consequently all information necessary to evaluate the compliance with the actual SOP. METHODS Q-Bot, an automatic DICOM metadata monitoring tool which is capable to verify SOP conformities, was tested for 11 months at two nuclear medicine departments. Relevant parameters, such as patient ID, patient mass and height, injected activity, and uptake time, were investigated in the case of adult 18F-FDG whole-body PET/CT and 99mTc-MDP gamma camera bone scans on a daily basis. Q-Bot automatically inspected the actual SOP compliance of these relevant DICOM parameters. Q-Bot graphical user interface (GUI) provided a summary of the outliers in a table format to be investigated by a dedicated technologist. In addition, information related to the error handling was also collected for retrospective analysis of long-term tendencies. RESULTS In total, 6702 PET/CT and 2502 gamma camera scans were inspected, from which 8581 were confirmed as valid patient study without errors. Discrepancies related to the lack of a parameter, not appropriate format, or improper scan procedures were found in 623 cases, and 156 out of these were corrected before the medical reading and reporting. SOP non-conformities explored with Q-Bot were found to be non-correctable in 467 cases. Systematic errors to our practice turned out to be the manual radiopharmaceutical injection, the allowance to use both SI and non-SI units, and the clear definition of decimal point symbol to use. CONCLUSION The daily evaluation of Q-Bot results provided early detection of errors and consequently ensured the minimization of error propagation. Integration of a QM software that inspects protocol compliance at a nuclear medicine department provides significant support to detect non-conformities for technologists, and much higher confidence in image quality for physicians.
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Affiliation(s)
- Ferenc Nagy
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary.
| | - Aron K Krizsan
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Kornél Kukuts
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | | | - Zsolt Hascsi
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Sandor Barna
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Antonietta Acs
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Peter Szabo
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Lajos Tron
- Medical Imaging Clinic-Nuclear Medicine, Clinical Center, University of Debrecen, Debrecen, Hungary
| | - Laszlo Balkay
- Medical Imaging Clinic-Nuclear Medicine, Clinical Center, University of Debrecen, Debrecen, Hungary
| | - Magnus Dahlbom
- Ahmanson Translational Imaging Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, USA
| | | | - Attila Forgacs
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
| | - Ildiko Garai
- ScanoMed Nuclear Medicine Centers, Nagyerdei krt. 98, Debrecen, H-4032, Hungary
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Okuda K, Hasegawa D, Kamiya T, Ichikawa H, Umeda T, Ohkubo T, Miwa K. Multicenter Study of Quantitative SPECT: Reproducibility of 99mTc Quantitation Using a Conjugated-Gradient Minimization Reconstruction Algorithm. J Nucl Med Technol 2021; 49:138-142. [PMID: 33419954 DOI: 10.2967/jnmt.120.256131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/03/2021] [Indexed: 11/16/2022] Open
Abstract
This multicenter study aimed to determine the reproducibility of quantitative SPECT images reconstructed using a commercially available method of ordered-subset conjugate-gradient minimization. Methods: A common cylindric phantom containing a 100 kBq/mL concentration of 99mTc-pertechnetate solution in a volume of 7 L was scanned under standard imaging conditions at 6 institutions using the local clinical protocol of each. Interinstitutional variation among the quantitative SPECT images was evaluated using the coefficient of variation. Dose calibrator accuracy was also investigated by measuring the same lot of commercially available 99mTc vials at each institution. Results: The respective radioactivity concentrations under standard and clinical conditions ranged from 95.71 ± 0.60 (mean ± SD) to 108.35 ± 0.36 kBq/mL and from 96.78 ± 0.64 to 108.49 ± 0.11 kBq/mL, respectively. Interinstitutional variation in radioactivity concentration was 4.20%. The bias in the radioactivity concentrations in SPECT images was associated with the accuracy of the dose calibrator at each institution. Conclusion: The reproducibility of the commercially available quantitative SPECT reconstruction method is high and comparable to that of PET, for comparatively large (∼7 L), homogeneous objects.
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Affiliation(s)
- Kyohei Okuda
- Department of Clinical Radiology, Tottori University Hospital, Yonago, Japan
| | - Daisuke Hasegawa
- Department of Radiology, Okayama Saiseikai General Hospital, Okayama, Japan
| | - Takashi Kamiya
- Division of Radiology, Department of Medical Technology, Osaka University Hospital, Suita, Japan
| | - Hajime Ichikawa
- Department of Radiology, Toyohashi Municipal Hospital, Toyohashi, Japan
| | - Takuro Umeda
- Department of Nuclear Medicine, Cancer Institution Hospital of Japan Foundation for Cancer Research, Tokyo, Japan
| | - Takushi Ohkubo
- Central Division of Radiology, Toho University Omori Medical Center, Tokyo, Japan; and
| | - Kenta Miwa
- School of Health Science, International University of Health and Welfare, Ohtawara, Japan
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López DF, Castro MA, Muñoz JM, Cárdenas-Perilla R. Reference values of mandibular condyles metabolic activity: A study using 99m Tc-MDP single-photon emission computed tomography. Orthod Craniofac Res 2020; 24:328-334. [PMID: 33090651 DOI: 10.1111/ocr.12434] [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: 06/28/2020] [Revised: 09/13/2020] [Accepted: 10/15/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To assess the condylar bone metabolic activity in patients with temporomandibular joint health by measuring 99m Tc-MDP uptake using a single-photon emission computed tomography (SPECT) to establish reference values of the uptake difference between condyles and the ratio with respect to the clivus. SETTING AND SAMPLE POPULATION Eighty consecutive patients of both sexes who were admitted to a Nuclear Medicine Centre between 2017 and 2019 were included in the study. METHOD This was an observational cross-sectional study in patients with SPECT indications to evaluate pathologies other than those of the temporomandibular joint. The values of the total and normalized counts in a fixed region of interest of five trans-axial slides were obtained to assess the percentage difference between the sides and the uptake ratio. The reference values are expressed as median and 5th and 95th percentiles. RESULTS The sample included 53 women (66.25%) and 27 men (33.75%) aged 15-55 years. The percentage of uptake difference between condyles was 5.04% (0.46-14.78) for men and 5.17% (0.27-13.21) for women (difference not significant, P = .9). The uptake difference was below 10% in 85% of the subjects (n = 68). The ratio values for total counts in women (0.87, 0.46-1.33) were significantly different (P = .0030) from those in men (1.08, 0.61-2.09). No significant correlation with age was found. CONCLUSIONS These new reference ranges are applicable to the diagnosis of unilateral and bilateral condylar hyperplasia.
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Affiliation(s)
- Diego Fernando López
- Orthodontics Graduate Program, School of Dentistry, Universidad del Valle, Cali, Colombia
| | - María Angélica Castro
- Orthodontics Graduate Program, School of Dentistry, Universidad del Valle, Cali, Colombia
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Gear J, Chiesa C, Lassmann M, Gabiña PM, Tran-Gia J, Stokke C, Flux G. EANM Dosimetry Committee series on standard operational procedures for internal dosimetry for 131I mIBG treatment of neuroendocrine tumours. EJNMMI Phys 2020; 7:15. [PMID: 32144574 PMCID: PMC7060302 DOI: 10.1186/s40658-020-0282-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 02/13/2020] [Indexed: 11/23/2022] Open
Abstract
The purpose of the EANM Dosimetry Committee Series on "Standard Operational Procedures for Dosimetry" (SOP) is to provide advice to scientists and clinicians on how to perform patient-specific absorbed dose assessments. This SOP describes image and data acquisition parameters and dosimetry calculations to determine the absorbed doses delivered to whole-body, tumour and normal organs following a therapeutic administration of 131I mIBG for the treatment of neuroblastoma or adult neuroendocrine tumours. Recommendations are based on evidence in recent literature where available and on expert opinion within the community. This SOP is intended to promote standardisation of practice within the community and as such is based on the facilities and expertise that should be available to any centre able to perform specialised treatments with radiopharmaceuticals and patient-specific dosimetry. A clinical example is given to demonstrate the application of the absorbed dose calculations.
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Affiliation(s)
- Jonathan Gear
- Joint Department of Physics, Royal Marsden Hospital & Institute of Cancer Research, Sutton, UK.
| | - Carlo Chiesa
- Nuclear Medicine, Foundation IRCCS Istituto Nazionale Tumori, Milan, Italy
| | - Michael Lassmann
- Department of Nuclear Medicine, University of Würzburg, 97080, Würzburg, Germany
| | - Pablo Mínguez Gabiña
- Department of Medical Physics and Radiation Protection, Gurutzeta/Cruces University Hospital, Barakaldo, Spain
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University of Würzburg, 97080, Würzburg, Germany
| | - Caroline Stokke
- Department of Diagnostic Physics, Division of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Glenn Flux
- Joint Department of Physics, Royal Marsden Hospital & Institute of Cancer Research, Sutton, UK
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Ljungberg M, Sjogreen Gleisner K. 3-D Image-Based Dosimetry in Radionuclide Therapy. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2018. [DOI: 10.1109/trpms.2018.2860563] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Determination of gamma camera calibration factors for quantitation of therapeutic radioisotopes. EJNMMI Phys 2018; 5:8. [PMID: 29717385 PMCID: PMC5930296 DOI: 10.1186/s40658-018-0208-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 02/23/2018] [Indexed: 01/23/2023] Open
Abstract
Background Camera calibration, which translates reconstructed count map into absolute activity map, is a prerequisite procedure for quantitative SPECT imaging. Both planar and tomographic scans using different phantom geometries have been proposed for the determination of the camera calibration factor (CF). However, there is no consensus on which approach is the best. The aim of this study is to evaluate all these calibration methods, compare their performance, and propose a practical and accurate calibration method for SPECT quantitation of therapeutic radioisotopes. Twenty-one phantom experiments (Siemens Symbia SPECT/CT) and 12 Monte Carlo simulations (GATE v6.1) using three therapy isotopes (131I, 177Lu, and 188Re) have been performed. The following phantom geometries were used: (1) planar scans of point source in air (PS), (2) tomographic scans of insert(s) filled with activity placed in non-radioactive water (HS + CB), (3) tomographic scans of hot insert(s) in radioactive water (HS + WB), and (4) tomographic scans of cylinders uniformly filled with activity (HC). Tomographic data were reconstructed using OSEM with CT-based attenuation correction and triple energy window (TEW) scatter correction, and CF was determined using total counts in the reconstructed image, while for planar scans, the photopeak counts, corrected for scatter and background with TEW, were used. Additionally, for simulated data, CF obtained from primary photons only was analyzed. Results For phantom experiments, CF obtained from PS and HS + WB agreed to within 6% (below 3% if experiments performed on the same day are considered). However, CF from HS + CB exceeded those from PS by 4–12%. Similar trend was found in simulation studies. Analysis of CFs from primary photons helped us to understand this discrepancy. It was due to underestimation of scatter by the TEW method, further enhanced by attenuation correction. This effect becomes less important when the source is distributed over the entire phantom volume (HS + WB and HC). Conclusions Camera CF could be determined using planar scans of a point source, provided that the scatter and background contributions are removed, for example using the clinically available TEW method. This approach is simple and yet provides CF with sufficient accuracy (~ 5%) to be used in clinics for radiotracer quantification.
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Li T, Ao ECI, Lambert B, Brans B, Vandenberghe S, Mok GSP. Quantitative Imaging for Targeted Radionuclide Therapy Dosimetry - Technical Review. Theranostics 2017; 7:4551-4565. [PMID: 29158844 PMCID: PMC5695148 DOI: 10.7150/thno.19782] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023] Open
Abstract
Targeted radionuclide therapy (TRT) is a promising technique for cancer therapy. However, in order to deliver the required dose to the tumor, minimize potential toxicity in normal organs, as well as monitor therapeutic effects, it is important to assess the individualized internal dosimetry based on patient-specific data. Advanced imaging techniques, especially radionuclide imaging, can be used to determine the spatial distribution of administered tracers for calculating the organ-absorbed dose. While planar scintigraphy is still the mainstream imaging method, SPECT, PET and bremsstrahlung imaging have promising properties to improve accuracy in quantification. This article reviews the basic principles of TRT and discusses the latest development in radionuclide imaging techniques for different theranostic agents, with emphasis on their potential to improve personalized TRT dosimetry.
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Affiliation(s)
- Tiantian Li
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China
| | - Edwin C. I. Ao
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China
| | - Bieke Lambert
- Dept of Radiology and Nuclear medicine, Ghent University, De Pintelaan 185 9000 Gent, Belgium
- AZ Maria Middelares, Buiten-Ring-Sint-Denijs 30, 9000 Gent, Belgium
| | - Boudewijn Brans
- Dept of Nuclear Medicine, UZ Ghent-Ghent University, St-Pietersnieuwstraat 41, 9000 Gent, Belgium
| | - Stefaan Vandenberghe
- MEDISIP-ELIS-IBITECH-IMEC, Ghent University, St-Pietersnieuwstraat 41, 9000 Gent, Belgium
| | - Greta S. P. Mok
- Biomedical Imaging Laboratory, Department of Electrical and Computer Engineering, Faculty of Science and Technology, University of Macau, Macau SAR, China
- Faculty of Health Sciences, University of Macau, Macau SAR, China
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Uncertainty Analysis in the Calibration of an Emission Tomography System for Quantitative Imaging. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:9830386. [PMID: 29312467 PMCID: PMC5660760 DOI: 10.1155/2017/9830386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 08/15/2017] [Indexed: 11/25/2022]
Abstract
It is generally acknowledged that calibration of the imaging system (be it a SPECT or a PET scanner) is one of the critical components associated with in vivo activity quantification in nuclear medicine. The system calibration is generally performed through the acquisition of a source with a known amount of radioactivity. The decay-corrected calibration factor is the “output” quantity in a measurement model for the process. This quantity is a function of a number of “input” variables, including total counts in the volume of interest (VOI), radionuclide activity concentration, source volume, acquisition duration, radionuclide half-life, and calibration time of the radionuclide. Uncertainties in the input variables propagate through the calculation to the “combined” uncertainty in the output quantity. In the present study, using the general formula given in the GUM (Guide to the Expression of Uncertainty in Measurement) for aggregating uncertainty components, we derive a practical relation to assess the combined standard uncertainty for the calibration factor of an emission tomography system. At a time of increasing need for accuracy in quantification studies, the proposed approach has the potential to be easily implemented in clinical practice.
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D’Arienzo M, Cozzella M, Fazio A, De Felice P, Iaccarino G, D’Andrea M, Ungania S, Cazzato M, Schmidt K, Kimiaei S, Strigari L. Quantitative 177 Lu SPECT imaging using advanced correction algorithms in non-reference geometry. Phys Med 2016; 32:1745-1752. [DOI: 10.1016/j.ejmp.2016.09.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/09/2016] [Accepted: 09/16/2016] [Indexed: 11/25/2022] Open
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Gamma camera calibration and validation for quantitative SPECT imaging with 177Lu. Appl Radiat Isot 2016; 112:156-64. [DOI: 10.1016/j.apradiso.2016.03.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 02/09/2016] [Accepted: 03/07/2016] [Indexed: 11/21/2022]
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Multicenter evaluation of single-photon emission computed tomography quantification with third-party reconstruction software. Nucl Med Commun 2016; 37:983-7. [PMID: 27128824 DOI: 10.1097/mnm.0000000000000538] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Reliable and reproducible quantification is essential in many clinical situations. Previously, single-photon emission computed tomography (SPECT) has not been considered a quantitative imaging modality, but recent advances in reconstruction algorithm development have made SPECT quantitative. In this study, we investigate the reproducibility of SPECT quantification with phantoms in a multicenter setting using novel third-party reconstruction software. A total of five hospitals and eight scanners (three GE scanners and five Siemens scanners) participated in the study. A Jaszczak phantom without inserts was used to calculate counts to activity concentration conversion factors. The quantitative accuracy was tested using the NEMA-IEC phantom with six spherical inserts (diameters from 10 to 37 mm) filled to an 8 : 1 insert-background concentration ratio. Phantom studies were reconstructed at one central location using HERMES HybridRecon applying corrections for attenuation, collimator-detector response, and scatter. Spherical volumes of interest with the same diameter as the inserts were drawn on the images and recovery coefficients for the spheres were calculated. The coefficient of variation (CoV) of the NEMA-IEC phantom recovery coefficients ranged from ∼19 to 5% depending on the insert diameter so that the lowest CoV was obtained with the largest spheres. The intersite CoV was almost equal to intrasite CoV. In conclusion, quantitative SPECT is reproducible in a multicenter setting with third-party reconstruction software.
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Zimmerman BE, Grošev D, Buvat I, Coca Pérez MA, Frey EC, Green A, Krisanachinda A, Lassmann M, Ljungberg M, Pozzo L, Quadir KA, Terán Gretter MA, Van Staden J, Poli GL. Multi-centre evaluation of accuracy and reproducibility of planar and SPECT image quantification: An IAEA phantom study. Z Med Phys 2016; 27:98-112. [PMID: 27105765 DOI: 10.1016/j.zemedi.2016.03.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/07/2016] [Accepted: 03/30/2016] [Indexed: 10/21/2022]
Abstract
Accurate quantitation of activity provides the basis for internal dosimetry of targeted radionuclide therapies. This study investigated quantitative imaging capabilities at sites with a variety of experience and equipment and assessed levels of errors in activity quantitation in Single-Photon Emission Computed Tomography (SPECT) and planar imaging. Participants from 9 countries took part in a comparison in which planar, SPECT and SPECT with X ray computed tomography (SPECT-CT) imaging were used to quantify activities of four epoxy-filled cylinders containing 133Ba, which was chosen as a surrogate for 131I. The sources, with nominal volumes of 2, 4, 6 and 23mL, were calibrated for 133Ba activity by the National Institute of Standards and Technology, but the activity was initially unknown to the participants. Imaging was performed in a cylindrical phantom filled with water. Two trials were carried out in which the participants first estimated the activities using their local standard protocols, and then repeated the measurements using a standardized acquisition and analysis protocol. Finally, processing of the imaging data from the second trial was repeated by a single centre using a fixed protocol. In the first trial, the activities were underestimated by about 15% with planar imaging. SPECT with Chang's first order attenuation correction (Chang-AC) and SPECT-CT overestimated the activity by about 10%. The second trial showed moderate improvements in accuracy and variability. Planar imaging was subject to methodological errors, e.g., in the use of a transmission scan for attenuation correction. The use of Chang-AC was subject to variability from the definition of phantom contours. The project demonstrated the need for training and standardized protocols to achieve good levels of quantitative accuracy and precision in a multicentre setting. Absolute quantification of simple objects with no background was possible with the strictest protocol to about 6% with planar imaging and SPECT (with Chang-AC) and within 2% for SPECT-CT.
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Affiliation(s)
- Brian E Zimmerman
- National Institute of Standards and Technology, Gaithersburg, MD, USA.
| | - Darko Grošev
- University Hospital Centre Zagreb, Zagreb, Croatia
| | - Irène Buvat
- Service Hospitalier Frédéric Joliot, Paris, France
| | | | | | - Alan Green
- National Physical Laboratory, Teddington, UK
| | | | | | | | - Lorena Pozzo
- Institute of Energy and Nuclear Research, São Paulo, Brazil
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Gustafsson J, Brolin G, Cox M, Ljungberg M, Johansson L, Gleisner KS. Uncertainty propagation for SPECT/CT-based renal dosimetry in177Lu peptide receptor radionuclide therapy. Phys Med Biol 2015; 60:8329-46. [DOI: 10.1088/0031-9155/60/21/8329] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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15
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Rowe SP, Vicente E, Anizan N, Wang H, Leal JP, Lodge MA, Frey EC, Wahl RL. Repeatability of Radiotracer Uptake in Normal Abdominal Organs with ¹¹¹In-Pentetreotide Quantitative SPECT/CT. J Nucl Med 2015; 56:985-8. [PMID: 25977467 DOI: 10.2967/jnumed.115.155358] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 04/15/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED With an increasing emphasis on quantitation of SPECT imaging and its use in dosimetry to guide therapies, it is desirable to understand the repeatability in normal-organ SPECT uptake values (SPECT-UVs). We investigated the variability of normal abdominal organ uptake in repeated (111)In-pentetreotide SPECT studies. METHODS Nine patients with multiple (111)In-pentetreotide SPECT/CT studies for clinical purposes were evaluated. Volumes of interest were drawn for the abdominal organs and applied to SPECT-UVs. The variability of those values was assessed. RESULTS The average SPECT-UV for the liver (1.7 ± 0.6) was much lower than for the kidneys (right, 8.0 ± 2.4; left, 7.5 ± 1.7). Interpatient and intrapatient variability was similar (intraclass correlation coefficients, 0.40-0.59) for all organs. The average coefficients of variation for each organ for each patient were obtained and averaged across all patients (0.26 for liver, 0.22 for right kidney, and 0.20 for left kidney). The coefficients of variation for the organs across all scans were 0.33 (liver), 0.30 (right kidney), and 0.22 (left kidney). CONCLUSION Variability across all patients and all scans for the liver was higher than reported with (18)F-FDG PET, though left kidney variability was similar to PET liver variability and left kidney uptake may be able to serve as an internal metric for determining the quantifiability of an (111)In-pentetreotide SPECT study.
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Affiliation(s)
- Steven P Rowe
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Esther Vicente
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Nadège Anizan
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Hao Wang
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jeffrey P Leal
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Martin A Lodge
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Eric C Frey
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Richard L Wahl
- The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Anizan N, Wang H, Zhou XC, Wahl RL, Frey EC. Factors affecting the repeatability of gamma camera calibration for quantitative imaging applications using a sealed source. Phys Med Biol 2015; 60:1325-37. [PMID: 25592130 DOI: 10.1088/0031-9155/60/3/1325] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Several applications in nuclear medicine require absolute activity quantification of single photon emission computed tomography images. Obtaining a repeatable calibration factor that converts voxel values to activity units is essential for these applications. Because source preparation and measurement of the source activity using a radionuclide activity meter are potential sources of variability, this work investigated instrumentation and acquisition factors affecting repeatability using planar acquisition of sealed sources. The calibration factor was calculated for different acquisition and geometry conditions to evaluate the effect of the source size, lateral position of the source in the camera field-of-view (FOV), source-to-camera distance (SCD), and variability over time using sealed Ba-133 sources. A small region of interest (ROI) based on the source dimensions and collimator resolution was investigated to decrease the background effect. A statistical analysis with a mixed-effects model was used to evaluate quantitatively the effect of each variable on the global calibration factor variability. A variation of 1 cm in the measurement of the SCD from the assumed distance of 17 cm led to a variation of 1-2% in the calibration factor measurement using a small disc source (0.4 cm diameter) and less than 1% with a larger rod source (2.9 cm diameter). The lateral position of the source in the FOV and the variability over time had small impacts on calibration factor variability. The residual error component was well estimated by Poisson noise. Repeatability of better than 1% in a calibration factor measurement using a planar acquisition of a sealed source can be reasonably achieved. The best reproducibility was obtained with the largest source with a count rate much higher than the average background in the ROI, and when the SCD was positioned within 5 mm of the desired position. In this case, calibration source variability was limited by the quantum noise.
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Affiliation(s)
- N Anizan
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
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