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Curkic Kapidzic S, Gustafsson J, Larsson E, Jessen L, Sjögreen Gleisner K. Kidney dosimetry in [ 177Lu]Lu-DOTA-TATE therapy based on multiple small VOIs. Phys Med 2024; 120:103335. [PMID: 38555793 DOI: 10.1016/j.ejmp.2024.103335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/24/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024] Open
Abstract
PURPOSE The aim was to investigate the use of multiple small VOIs for kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy. METHOD The study was based on patient and simulated SPECT images in anthropomorphic geometries. Images were reconstructed using two reconstruction programs (local LundaDose and commercial Hermia) using OS-EM with and without resolution recovery (RR). Five small VOIs were placed to determine the average activity concentration (AC) in each kidney. The study consisted of three steps: (i) determination of the number of iterations for AC convergence based on simulated images; (ii) determination of recovery-coefficients (RCs) for 2 mL VOIs using a separate set of simulated images; (iii) assessment of operator variability in AC estimates for simulated and patient images. Five operators placed the VOIs, using for guidance: a) SPECT/CT with RR, b) SPECT/CT without RR, and c) CT only. For simulated images, time-integrated ACs (TIACs) were evaluated. For patient images, estimated ACs were compared with results of a previous method based on whole-kidney VOIs. RESULTS Eight iterations and ten subsets were sufficient for both programs and reconstruction settings. Mean RCs (mean ± SD) with RR were 1.03 ± 0.02 (LundaDose) and 1.10 ± 0.03 (Hermia), and without RR 0.91 ± 0.03 (LundaDose) and 0.94 ± 0.03 (Hermia). Most stable and accurate estimates of the AC were obtained using five 2-mL VOIs guided by SPECT/CT with RR, applying them to images without RR, and including an explicit RC for recovery correction. CONCLUSION The small VOI method based on five 2-mL VOIs was found efficient and sufficiently accurate for kidney dosimetry in [177Lu]Lu-DOTA-TATE therapy.
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Affiliation(s)
- Selma Curkic Kapidzic
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden; Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden.
| | | | - Erik Larsson
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Sweden
| | - Lovisa Jessen
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden
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Nuttens V, Schramm G, D'Asseler Y, Koole M. Comparison of a 3D CZT and conventional SPECT/CT system for quantitative Lu-177 SPECT imaging. EJNMMI Phys 2024; 11:29. [PMID: 38499797 PMCID: PMC10948674 DOI: 10.1186/s40658-024-00627-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 02/27/2024] [Indexed: 03/20/2024] Open
Abstract
PURPOSE Next-generation SPECT/CT systems with CdZnTe (CZT) digital detectors in a ring-like setup are emerging to perform quantitative Lu-177 SPECT imaging in clinical routine. It is essential to assess how the shorter acquisition time might affect the image quality and uncertainty on the mean absorbed dose of the tumors and organs at risk compared to a conventional system. METHODS A NEMA Image Quality phantom was scanned with a 3D CZT SPECT/CT system (Veriton, by Spectrum Dynamics) using 6 min per bed position and with a conventional SPECT/CT system (Symbia T16, by Siemens) using 16 min per bed position. The sphere-to-background ratio was 12:1 and the background activity concentration ranged from 0.52 to 0.06 MBq/mL. A clinical reconstruction protocol for dosimetry purposes was determined for both systems by maximizing the sphere-to-background ratio while keeping the coefficient of variation of the background as low as possible. The corresponding image resolution was determined by the matching filter method and used for a dose uncertainty assessment of both systems following an established uncertainty model.. RESULTS The optimized iterative reconstruction protocol included scatter and attenuation correction for both systems and detector response modeling for the Siemens system. For the 3D CZT system, 6 iterations and 8 subsets were combined with a Gaussian post-filter of 3 mm Full Width Half Maximum (FWHM) for post-smoothing. For the conventional system, 16 iterations and 16 subsets were applied with a Gaussian post-smoothing filter of 1 mm FWHM. For these protocols, the sphere-to-background ratio was 18.5% closer to the true ratio for the conventional system compared to the 3D CZT system when considering the four largest spheres. Meanwhile, the background coefficient of variation was very similar for both systems. These protocols resulted in SPECT image resolution of 14.8 mm and 13.6 mm for the 3D CZT and conventional system respectively. Based on these resolution estimates, a 50% dose uncertainty corresponded to a lesion volume of 28 mL for the conventional system and a lesion volume of 33 mL for the 3D CZT system. CONCLUSIONS An optimized reconstruction protocol for a Veriton system with 6 min of acquisition time per bed position resulted in slightly higher dose uncertainties than a conventional Symbia system using 16 min of acquisition time per bed position. Therefore, a 3D CZT SPECT/CT allows to significantly reduce the acquisition times with only a very limited impact on dose uncertainties such that quantitative Lu-177 SPECT/CT imaging becomes much more accessible for treatment concurrent dosimetry. Nevertheless, the uncertainty of SPECT-based dose estimates remains high.
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Affiliation(s)
- Victor Nuttens
- Nuclear Medicine, OLV Aalst, Aalst, Belgium.
- Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium.
| | - Georg Schramm
- Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium
| | - Yves D'Asseler
- Nuclear Medicine, Ghent University Hospital, Ghent, Belgium
- Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Michel Koole
- Nuclear Medicine and Molecular Imaging, KU Leuven, Leuven, Belgium
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Jessen L, Gustafsson J, Ljungberg M, Curkic-Kapidzic S, Imsirovic M, Sjögreen-Gleisner K. 3D printed non-uniform anthropomorphic phantoms for quantitative SPECT. EJNMMI Phys 2024; 11:8. [PMID: 38252205 PMCID: PMC10803701 DOI: 10.1186/s40658-024-00613-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 01/15/2024] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND A 3D printing grid-based method was developed to construct anthropomorphic phantoms with non-uniform activity distributions, to be used for evaluation of quantitative SPECT images. The aims were to characterize the grid-based method and to evaluate its capability to provide realistically shaped phantoms with non-uniform activity distributions. METHODS Characterization of the grid structures was performed by printing grid-filled spheres. Evaluation was performed by micro-CT imaging to investigate the printing accuracy and by studying the modulation contrast ([Formula: see text]) in SPECT images for 177Lu and 99mTc as a function of the grid fillable-volume fraction (FVF) determined from weighing. The grid-based technique was applied for the construction of two kidney phantoms and two thyroid phantoms, designed using templates from the XCAT digital phantoms. The kidneys were constructed with a hollow outer container shaped as cortex, an inner grid-based structure representing medulla and a solid section representing pelvis. The thyroids consisted of two lobes printed as grid-based structures, with void hot spots within the lobes. The phantoms were filled with solutions of 177Lu (kidneys) or 99mTc (thyroids) and imaged with SPECT. For verification, Monte Carlo simulations of SPECT imaging were performed for activity distributions corresponding to those of the printed phantoms. Measured and simulated SPECT images were compared qualitatively and quantitatively. RESULTS Micro-CT images showed that printing inaccuracies were mainly uniform across the grid. The relationships between the FVF from weighing and [Formula: see text] were found to be linear (r = 0.9995 and r = 0.9993 for 177Lu and 99mTc, respectively). The FVF-deviations from the design were up to 15% for thyroids and 4% for kidneys, mainly related to possibilities of cleaning after printing. Measured and simulated SPECT images of kidneys and thyroids exhibited similar activity distributions and quantitative comparisons agreed well, thus verifying the grid-based method. CONCLUSIONS We find the grid-based technique useful for the provision of 3D printed, realistically shaped, phantoms with non-uniform activity distributions, which can be used for evaluation of different quantitative methods in SPECT imaging.
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Affiliation(s)
- Lovisa Jessen
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden.
| | | | | | - Selma Curkic-Kapidzic
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
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Gustafsson J, Taprogge J. Future trends for patient-specific dosimetry methodology in molecular radiotherapy. Phys Med 2023; 115:103165. [PMID: 37880071 DOI: 10.1016/j.ejmp.2023.103165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Molecular radiotherapy is rapidly expanding, and new radiotherapeutics are emerging. The majority of treatments is still performed using empirical fixed activities and not tailored for individual patients. Molecular radiotherapy dosimetry is often seen as a promising candidate that would allow personalisation of treatments as outcome should ultimately depend on the absorbed doses delivered and not the activities administered. The field of molecular radiotherapy dosimetry has made considerable progress towards the feasibility of routine clinical dosimetry with reasonably accurate absorbed-dose estimates for a range of molecular radiotherapy dosimetry applications. A range of challenges remain with respect to the accurate quantification, assessment of time-integrated activity and absorbed dose estimation. In this review, we summarise a range of technological and methodological advancements, mainly focussed on beta-emitting molecular radiotherapeutics, that aim to improve molecular radiotherapy dosimetry to achieve accurate, reproducible, and streamlined dosimetry. We describe how these new technologies can potentially improve the often time-consuming considered process of dosimetry and provide suggestions as to what further developments might be required.
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Affiliation(s)
| | - Jan Taprogge
- National Radiotherapy Trials Quality Assurance (RTTQA) Group, Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton SM2 5PT, United Kingdom; The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, United Kingdom
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Rahman MA, Li Z, Yu Z, Laforest R, Thorek DLJ, Jha AK. A list-mode multi-energy window low-count SPECT reconstruction method for isotopes with multiple emission peaks. EJNMMI Phys 2023; 10:40. [PMID: 37347319 PMCID: PMC10287621 DOI: 10.1186/s40658-023-00558-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 05/31/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Single-photon emission computed tomography (SPECT) provides a mechanism to perform absorbed-dose quantification tasks for [Formula: see text]-particle radiopharmaceutical therapies ([Formula: see text]-RPTs). However, quantitative SPECT for [Formula: see text]-RPT is challenging due to the low number of detected counts, the complex emission spectrum, and other image-degrading artifacts. Towards addressing these challenges, we propose a low-count quantitative SPECT reconstruction method for isotopes with multiple emission peaks. METHODS Given the low-count setting, it is important that the reconstruction method extracts the maximal possible information from each detected photon. Processing data over multiple energy windows and in list-mode (LM) format provide mechanisms to achieve that objective. Towards this goal, we propose a list-mode multi energy window (LM-MEW) ordered-subsets expectation-maximization-based SPECT reconstruction method that uses data from multiple energy windows in LM format and include the energy attribute of each detected photon. For computational efficiency, we developed a multi-GPU-based implementation of this method. The method was evaluated using 2-D SPECT simulation studies in a single-scatter setting conducted in the context of imaging [[Formula: see text]Ra]RaCl[Formula: see text], an FDA-approved RPT for metastatic prostate cancer. RESULTS The proposed method yielded improved performance on the task of estimating activity uptake within known regions of interest in comparison to approaches that use a single energy window or use binned data. The improved performance was observed in terms of both accuracy and precision and for different sizes of the region of interest. CONCLUSIONS Results of our studies show that the use of multiple energy windows and processing data in LM format with the proposed LM-MEW method led to improved quantification performance in low-count SPECT of isotopes with multiple emission peaks. These results motivate further development and validation of the LM-MEW method for such imaging applications, including for [Formula: see text]-RPT SPECT.
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Affiliation(s)
- Md Ashequr Rahman
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
| | - Zekun Li
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
| | - Zitong Yu
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
| | - Richard Laforest
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
| | - Daniel L. J. Thorek
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
| | - Abhinav K. Jha
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, USA
- Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, USA
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Desy A, Bouvet GF, Croteau É, Lafrenière N, Turcotte ÉE, Després P, Beauregard JM. Quantitative SPECT (QSPECT) at high count rates with contemporary SPECT/CT systems. EJNMMI Phys 2021; 8:73. [PMID: 34718900 DOI: 10.1186/s40658-021-00421-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/14/2021] [Indexed: 12/02/2022] Open
Abstract
Background Accurate QSPECT is crucial in dosimetry-based, personalized radiopharmaceutical therapy with 177Lu and other radionuclides. We compared the quantitative performance of three NaI(Tl)-crystal SPECT/CT systems equipped with low-energy high-resolution collimators from two vendors (Siemens Symbia T6; GE Discovery 670 and NM/CT 870 DR). Methods Using up to 14 GBq of 99mTc in planar mode, we determined the calibration factor and dead-time constant under the assumption that these systems have a paralyzable behaviour. We monitored their response when one or both detectors were activated. QSPECT capability was validated by SPECT/CT imaging of a customized NEMA phantom containing up to 17 GBq of 99mTc. Acquisitions were reconstructed with a third-party ordered subset expectation maximization algorithm. Results The Siemens system had a higher calibration factor (100.0 cps/MBq) and a lower dead-time constant (0.49 μs) than those from GE (75.4–87.5 cps/MBq; 1.74 μs). Activities of up to 3.3 vs. 2.3–2.7 GBq, respectively, were quantifiable by QSPECT before the observed count rate plateaued or decreased. When used in single-detector mode, the QSPECT capability of the former system increased to 5.1 GBq, whereas that of the latter two systems remained independent of the detectors activation mode. Conclusion Despite similar hardware, SPECT/CT systems’ response can significantly differ at high count rate, which impacts their QSPECT capability in a post-therapeutic setting. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00421-3.
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Kupitz D, Wissel H, Wuestemann J, Bluemel S, Pech M, Amthauer H, Kreissl MC, Grosser OS. Optimization of SPECT/CT imaging protocols for quantitative and qualitative 99mTc SPECT. EJNMMI Phys 2021; 8:57. [PMID: 34328565 PMCID: PMC8324619 DOI: 10.1186/s40658-021-00405-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022] Open
Abstract
Background The introduction of hybrid SPECT/CT devices enables quantitative imaging in SPECT, providing a methodological setup for quantitation using SPECT tracers comparable to PET/CT. We evaluated a specific quantitative reconstruction algorithm for SPECT data using a 99mTc-filled NEMA phantom. Quantitative and qualitative image parameters were evaluated for different parametrizations of the acquisition and reconstruction protocol to identify an optimized quantitative protocol. Results The reconstructed activity concentration (ACrec) and the signal-to-noise ratio (SNR) of all examined protocols (n = 16) were significantly affected by the parametrization of the weighting factor k used in scatter correction, the total number of iterations and the sphere volume (all, p < 0.0001). The two examined SPECT acquisition protocols (with 60 or 120 projections) had a minor impact on the ACrec and no significant impact on the SNR. In comparison to the known AC, the use of default scatter correction (k = 0.47) or object-specific scatter correction (k = 0.18) resulted in an underestimation of ACrec in the largest sphere volume (26.5 ml) by − 13.9 kBq/ml (− 16.3%) and − 7.1 kBq/ml (− 8.4%), respectively. An increase in total iterations leads to an increase in estimated AC and a decrease in SNR. The mean difference between ACrec and known AC decreased with an increasing number of total iterations (e.g., for 20 iterations (2 iterations/10 subsets) = − 14.6 kBq/ml (− 17.1%), 240 iterations (24i/10s) = − 8.0 kBq/ml (− 9.4%), p < 0.0001). In parallel, the mean SNR decreased significantly from 2i/10s to 24i/10s by 76% (p < 0.0001). Conclusion Quantitative SPECT imaging is feasible with the used reconstruction algorithm and hybrid SPECT/CT, and its consistent implementation in diagnostics may provide perspectives for quantification in routine clinical practice (e.g., assessment of bone metabolism). When combining quantitative analysis and diagnostic imaging, we recommend using two different reconstruction protocols with task-specific optimized setups (quantitative vs. qualitative reconstruction). Furthermore, individual scatter correction significantly improves both quantitative and qualitative results. Supplementary Information The online version contains supplementary material available at 10.1186/s40658-021-00405-3.
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Affiliation(s)
- Dennis Kupitz
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.
| | - Heiko Wissel
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany
| | - Jan Wuestemann
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany
| | - Stephanie Bluemel
- Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Maciej Pech
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Holger Amthauer
- Department of Nuclear Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Michael C Kreissl
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
| | - Oliver S Grosser
- Department of Radiology and Nuclear Medicine, University Hospital Magdeburg, Magdeburg, Germany.,Research Campus STIMULATE, Otto-von-Guericke University, Magdeburg, Germany
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van de Burgt A, Dibbets-Schneider P, Slump CH, Scholte AJHA, Atsma DE, de Geus-Oei LF, van Velden FHP. Experimental validation of absolute SPECT/CT quantification for response monitoring in patients with coronary artery disease. EJNMMI Phys 2021; 8:48. [PMID: 34132918 PMCID: PMC8208344 DOI: 10.1186/s40658-021-00393-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 06/08/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Quantitative SPECT enables absolute quantification of uptake in perfusion defects. The aim of this experimental study is to assess quantitative accuracy and precision of a novel iterative reconstruction technique (Evolution; GE Healthcare) for the potential application of response monitoring using 99mTc-tetrofosmin SPECT/CT in patients with coronary artery disease (CAD). METHODS Acquisitions of an anthropomorphic torso phantom with cardiac insert containing defects (with varying sizes), filled with 99mTc-pertechnetate, were performed on a SPECT/CT (Discovery 670 Pro, GE Healthcare). Subsequently, volumes of interest of the defects were manually drawn on CT to assess the recovery coefficient (RC). Bull's eye plots were composed to evaluate the uptake per segment. Finally, 99mTc-tetrofosmin SPECT/CT scans of 10 CAD patients were used to illustrate clinical application. RESULTS The phantom study indicated that Evolution showed convergence after 7 iterations and 10 subsets. The average repeatability deviation of all configurations was 2.91% and 3.15% (%SD mean) for filtered (Butterworth) and unfiltered data, respectively. The accuracy after post-filtering was lower compared to the unfiltered data with a mean (SD) RC of 0.63 (0.05) and 0.70 (0.07), respectively (p < 0.05). More artificial defects were found on Bull's eye plots created with the unfiltered data compared to filtered data. Eight out of ten patients showed significant changes in uptake before and after treatment (p < 0.05). CONCLUSION Quantification of 99mTc-tetrofosmin SPECT/CT seems feasible for CAD patients when 7 iterations (10 subsets), Butterworth post-filtering (cut off frequency 0.52 in cycles/cm, order of 5) and manual CT-delineation are applied. However, future prospective patient studies are required for clinical application.
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Affiliation(s)
- Alina van de Burgt
- Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands.
| | - Petra Dibbets-Schneider
- Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
| | - Cornelis H Slump
- Technical Medical Center, University of Twente, Enschede, The Netherlands
| | - Arthur J H A Scholte
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Douwe E Atsma
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lioe-Fee de Geus-Oei
- Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands.,Biomedical Photonic Imaging Group, University of Twente, Enschede, The Netherlands
| | - Floris H P van Velden
- Department of Radiology, Section of Nuclear Medicine, Leiden University Medical Center, PO Box 9600, 2300 RC, Leiden, The Netherlands
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Desy A, Bouvet GF, Frezza A, Després P, Beauregard JM. Impact of dead time on quantitative 177Lu-SPECT (QSPECT) and kidney dosimetry during PRRT. EJNMMI Phys 2020; 7:32. [PMID: 32415492 PMCID: PMC7229114 DOI: 10.1186/s40658-020-00303-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/05/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Dead time may affect the accuracy of quantitative SPECT (QPSECT), and thus of dosimetry. The aim of this study was to quantify the effect of dead time on 177Lu-QSPECT and renal dosimetry following peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumours. METHODS QSPECT/CT was performed on days 1 and 3 during 564 personalized 177Lu-octreotate cycles in 166 patients. The dead-time data for each scanning time point was compiled. The impact of not correcting QSPECT for the dead time was assessed for the kidney dosimetry. This was also estimated for empiric PRRT by simulating in our cohort a regime of 7.4 GBq/cycle. RESULTS The probability to observe a larger dead time increased with the injected activity. A dead-time loss greater than 5% affected 14.4% and 5.7% of QSPECT scans performed at days 1 and 3, respectively. This resulted in renal absorbed dose estimates that would have been underestimated by more than 5% in 5.7% of cycles if no dead-time correction was applied, with a maximum underestimation of 22.1%. In the simulated empiric regime, this potential dose underestimation would have been limited to 6.2%. CONCLUSION Dead-time correction improves the accuracy of dosimetry in 177Lu radionuclide therapy and is warranted in personalized PRRT.
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Affiliation(s)
- Alessandro Desy
- Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada
| | - Guillaume F Bouvet
- Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada
| | - Andrea Frezza
- Cancer Research Centre and Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada
| | - Philippe Després
- Cancer Research Centre and Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada.,Department of Radiation Oncology and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada
| | - Jean-Mathieu Beauregard
- Cancer Research Centre and Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, Canada. .,Department of Medical Imaging and Oncology Division of Research Centre, CHU de Québec-Université Laval, 11 côte du Palais, Quebec City, G1R 2J6, Canada.
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Frezza A, Desport C, Uribe C, Zhao W, Celler A, Després P, Beauregard JM. Comprehensive SPECT/CT system characterization and calibration for 177Lu quantitative SPECT (QSPECT) with dead-time correction. EJNMMI Phys 2020; 7:10. [PMID: 32060777 PMCID: PMC7021856 DOI: 10.1186/s40658-020-0275-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 01/26/2020] [Indexed: 12/31/2022] Open
Abstract
Background Personalization of 177Lu-based radionuclide therapy requires implementation of dosimetry methods that are both accurate and practical enough for routine clinical use. Quantitative single-photon emission computed tomography/computed tomography (QSPECT/CT) is the preferred scanning modality to achieve this and necessitates characterizing the response of the camera, and calibrating it, over the full range of therapeutic activities and system capacity. Various methods to determine the camera calibration factor (CF) and the deadtime constant (τ) were investigated, with the aim to design a simple and robust protocol for quantitative 177Lu imaging. Methods The SPECT/CT camera was equipped with a medium energy collimator. Multiple phantoms were used to reproduce various attenuation conditions: rod sources in air or water-equivalent media, as well as a Jaszczak phantom with inserts. Planar and tomographic images of a wide range of activities were acquired, with multiple energy windows for scatter correction (double or triple energy window technique) as well as count rate monitoring over a large spectrum of energy. Dead time was modelled using the paralysable model. CF and τ were deduced by curve fitting either separately in two steps (CF determined first using a subset of low-activity acquisitions, then τ determined using the full range of activity) or at once (both CF and τ determined using the full range of activity). Total or segmented activity in the SPECT field of view was computed. Finally, these methods were compared in terms of accuracy to recover the known activity, in particular when planar-derived parameters were applied to the SPECT data. Results The SPECT camera was shown to operate as expected on a finite count rate range (up to ~ 350 kcps over the entire energy spectrum). CF and τ from planar (sources in air) and SPECT segmented Jaszczak data yielded a very good agreement (CF < 1% and τ < 3%). Determining CF and τ from a single curve fit made dead-time-corrected images less prone to overestimating recovered activity. Using triple-energy window scatter correction while acquiring one or more additional energy window(s) to enable wide-spectrum count rate monitoring (i.e. ranging 55–250 or 18–680 keV) yielded the most consistent results across the various geometries. The final, planar-derived calibration parameters for our system were a CF of 9.36 ± 0.01 cps/MBq and a τ of 0.550 ± 0.003 μs. Using the latter, the activity in a Jaszczak phantom could be quantified by QSPECT with an accuracy of 0.02 ± 1.10%. Conclusions Serial planar acquisitions of sources in air using an activity range covering the full operational capacity of the SPECT/CT system, with multiple energy windows for wide-spectrum count rate monitoring, and followed by simultaneous determination of CF and τ using a single equation derived from the paralysable model, constitutes a practical method to enable accurate dead-time-corrected QSPECT imaging in a post-177Lu radionuclide therapy setting.
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Affiliation(s)
- Andrea Frezza
- Cancer Research Center, Université Laval, Quebec City, QC, Canada.,Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada.,Oncology Division, CHU de Québec - Université Laval Research Center, Quebec City, QC, Canada
| | - Corentin Desport
- Cancer Research Center, Université Laval, Quebec City, QC, Canada.,Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada.,Oncology Division, CHU de Québec - Université Laval Research Center, Quebec City, QC, Canada
| | - Carlos Uribe
- Functional Imaging Department, BC Cancer, Vancouver, BC, Canada
| | - Wei Zhao
- Medical Imaging Research Group, Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Anna Celler
- Medical Imaging Research Group, Department of Radiology, University of British Columbia, Vancouver, BC, Canada
| | - Philippe Després
- Cancer Research Center, Université Laval, Quebec City, QC, Canada.,Department of Physics, Engineering Physics and Optics, Université Laval, Quebec City, QC, Canada.,Oncology Division, CHU de Québec - Université Laval Research Center, Quebec City, QC, Canada.,Department of Radiation Oncology, CHU de Québec - Université Laval, Quebec City, QC, Canada
| | - Jean-Mathieu Beauregard
- Cancer Research Center, Université Laval, Quebec City, QC, Canada. .,Oncology Division, CHU de Québec - Université Laval Research Center, Quebec City, QC, Canada. .,Department of Radiology and Nuclear Medicine, Université Laval, Quebec City, QC, Canada. .,Department of Medical Imaging, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada.
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11
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Tabotta F, Jreige M, Schaefer N, Becce F, Prior JO, Nicod Lalonde M. Quantitative bone SPECT/CT: high specificity for identification of prostate cancer bone metastases. BMC Musculoskelet Disord 2019; 20:619. [PMID: 31878904 DOI: 10.1186/s12891-019-3001-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 12/11/2019] [Indexed: 12/21/2022] Open
Abstract
Purpose Bone scintigraphy with 99mTc-labeled diphosphonates can identify prostate cancer bone metastases with high sensitivity, but relatively low specificity, because benign conditions such as osteoarthritis can also trigger osteoblastic reactions. We aimed to investigate the diagnostic performance of 99mTc-2,3-dicarboxy propane-1,1-diphosphonate (99mTc-DPD) uptake quantification by single-photon emission computed tomography coupled with computed tomography (SPECT/CT) for distinguishing prostate cancer bone metastases from spinal and pelvic osteoarthritic lesions. Methods We retrospectively assessed 26 bone scans from 26 patients with known prostate cancer bone metastases and 13 control patients with benign spinal and pelvic osteoarthritic changes without known neoplastic disease. Quantitative SPECT/CT (xSPECT, Siemens Symbia Intevo, Erlangen, Germany) was performed and standardized uptake values (SUVs) were quantified with measurements of SUVmax and SUVmean (g/mL) in all bone metastases for the prostate cancer group and in spinal and pelvic osteoarthritic changes for the control group. We used receiver operating characteristics (ROC) curves to determine the optimum SUVmax cutoff value to distinguish between bone metastases and benign spinal and pelvic lesions. Results In total, 264 prostate cancer bone metastases were analyzed, showing a mean SUVmax and SUVmean of 34.6 ± 24.6 and 20.8 ± 14.7 g/mL, respectively. In 24 spinal and pelvic osteoarthritic lesions, mean SUVmax and SUVmean were 14.2 ± 3.8 and 8.9 ± 2.2 g/mL, respectively. SUVmax and SUVmean were both significantly different between the bone metastases and osteoarthritic groups (p ≤ 0.0001). Using a SUVmax cutoff of 19.5 g/mL for prostate cancer bone metastases in the spine and pelvis, sensitivity, specificity, positive and negative predictive values were 87, 92, 99 and 49%, respectively. Conclusion This study showed significant differences in quantitative 99mTc-DPD uptake on bone SPECT/CT between prostate cancer bone metastases and spinal and pelvic osteoarthritic changes, with higher SUVmax and SUVmean in metastases. Using a SUVmax cutoff of 19.5 g/mL, high specificity and positive predictive value for metastases identification in the spine and pelvis were found, thus increasing accuracy of bone scintigraphy.
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12
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Vija AH, Bartenstein PA, Froelich JW, Kuwert T, Macapinlac H, Daignault CP, Gowda N, Hadjiev O, Hephzibah J, Huang P, Ilhan H, Jessop A, Cachovan M, Ma J, Ding X, Spence D, Platsch G, Szabo Z. ROC study and SUV threshold using quantitative multi-modal SPECT for bone imaging. Eur J Hybrid Imaging 2019; 3:10. [PMID: 34191147 PMCID: PMC8218047 DOI: 10.1186/s41824-019-0057-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 05/24/2019] [Indexed: 11/23/2022] Open
Abstract
Background We investigated the clinical performance of a quantitative multi-modal SPECT/CT reconstruction platform for yielding radioactivity concentrations of bone imaging with 99mTc-methylene diphosphonate (MDP) or 99mTc-dicarboxypropane diphosphonate (DPD). The novel reconstruction incorporates CT-derived tissue information while preserving the delineation of tissue boundaries. We assessed image-based reader concordance and confidence, and determined lesion classification and SUV thresholds from ROC analysis. Methods Seventy-two cancer patients were scanned at three US and two German clinical sites, each contributing two experienced board-certified nuclear medicine physicians as readers. We compared four variants of the reconstructed data resulting from the Flash3D (F3D) and the xSPECT Bone™ (xB) iterative reconstruction methods and presented images to the readers with and without a fused CT, resulting in four combinations. We used an all-or-none approach for inclusion, compiling results only when a reader completed all reads in a subset. After the final read, we conducted a “surrogate truth” reading, presenting all data to each reader. For any remaining discordant lesions, we conducted a consensus read. We next undertook ROC analysis to determine SUV thresholds for differentiating benign and lesional uptake. Results On a five-point rating scale of image quality, xB was deemed better by almost two points in resolution and one point better in overall acceptance compared to F3D. The absolute agreement of the rendered decision between the nine readers was significantly higher with CT information either inside the reconstruction (xB, xBCT) or simply through image fusion (F3DCT): 0.70 (xBCT), 0.67 (F3DCT), 0.64 (xB), and 0.46 (F3D). The confidence level to characterize the lesion was significantly higher (3.03x w/o CT, 1.32x w/CT) for xB than for F3D. There was high correlation between xB and F3D scores for lesion detection and classification, but lesion detection confidence was 41% higher w/o CT, and 21% higher w/CT for xB compared to F3D. Without CT, xB had 6.6% higher sensitivity, 7.1% higher specificity, and 6.9% greater AUC compared to F3D, and similarly with CT-fusion. The overall SUV-criterion (SUVc) of xB (12) exceeded that for xSPECT Quant™ (xQ; 9), an approach not using the tissue delineation of xB. SUV critical numbers depended on lesion volume and location. For non-joint lesions > 6 ml, the AUC for xQ and xB was 94%, with SUVc > 9.28 (xQ) or > 9.68 (xB); for non-joint lesions ≤ 6 ml, AUCs were 81% (xQ) and 88% (xB), and SUVc > 8.2 (xQ) or > 9.1 (xB). For joint lesions, the AUC was 80% (xQ) and 83% (xB), with SUVc > 8.61 (xQ) or > 13.4 (xB). Conclusion The incorporation of high-resolution CT-based tissue delineation in SPECT reconstruction (xSPECT Bone) provides better resolution and detects smaller lesions (6 ml), and the CT component facilitates lesion characterization. Our approach increases confidence, concordance, and accuracy for readers with a wide range of experience. The xB method retained high reading accuracy, despite the unfamiliar image presentation, having greatest impact for smaller lesions, and better localization of foci relative to bone anatomy. The quantitative assessment yielded an SUV-threshold for sensitively distinguishing benign and malignant lesions. Ongoing efforts shall establish clinically usable protocols and SUV thresholds for decision-making based on quantitative SPECT.
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Affiliation(s)
- A H Vija
- Molecular Imaging, Siemens Medical Solutions USA, Inc, Hoffman Estates, IL, USA.
| | | | | | - T Kuwert
- Friedrich Alexander Universität Erlangen, Erlangen, Germany
| | | | - C P Daignault
- University of Minnesota, Minneapolis, MN, USA.,Veterans Medical Center, Minneapolis, MN, USA
| | - N Gowda
- University of Minnesota, Minneapolis, MN, USA.,Consulting Radiology, Edina, MN, USA
| | - O Hadjiev
- University of Minnesota, Minneapolis, MN, USA.,Milwaukee Radiologists, Greenfield, WI, USA
| | - J Hephzibah
- Johns Hopkins University, Baltimore, MD, USA.,Christian Medical College, Vellore, India
| | - P Huang
- Johns Hopkins University, Baltimore, MD, USA
| | - H Ilhan
- Ludwig-Maximilians Universität, München, Munich, Germany
| | - A Jessop
- MD Anderson Cancer Center, Houston, TX, USA.,Vanderbilt University Medical Center, Nashville, TN, USA
| | - M Cachovan
- Siemens Healthineers GmbH, Erlangen, Germany
| | - J Ma
- Molecular Imaging, Siemens Medical Solutions USA, Inc, Hoffman Estates, IL, USA
| | - X Ding
- Molecular Imaging, Siemens Medical Solutions USA, Inc, Hoffman Estates, IL, USA
| | - D Spence
- Molecular Imaging, Siemens Medical Solutions USA, Inc, Hoffman Estates, IL, USA
| | - G Platsch
- Siemens Healthineers GmbH, Erlangen, Germany
| | - Z Szabo
- Johns Hopkins University, Baltimore, MD, USA
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Ross JC, Vilić D, Sanderson T, Vöö S, Dickson J. Does quantification have a role to play in the future of bone SPECT? Eur J Hybrid Imaging 2019; 3:8. [PMID: 34191209 PMCID: PMC8218028 DOI: 10.1186/s41824-019-0054-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/01/2019] [Indexed: 12/26/2022] Open
Abstract
Routinely, there is a visual basis to nuclear medicine reporting: a reporter subjectively places a patient's condition into one of multiple discrete classes based on what they see. The addition of a quantitative result, such as a standardised uptake value (SUV), would provide a numerical insight into the nature of uptake, delivering greater objectivity, and perhaps improved patient management.For bone scintigraphy in particular quantification could increase the accuracy of diagnosis by helping to differentiate normal from abnormal uptake. Access to quantitative data might also enhance our ability to characterise lesions, stratify and monitor patients' conditions, and perform reliable dosimetry for radionuclide therapies. But is there enough evidence to suggest that we, as a community, should be making more effort to implement quantitative bone SPECT in routine clinical practice?We carried out multiple queries through the PubMed search engine to facilitate a cross-sectional review of the current status of bone SPECT quantification. Highly cited papers were assessed in more focus to scrutinise their conclusions.An increasing number of authors are reporting findings in terms of metrics such as SUVmax. Although interest in the field in general remains high, the rate of clinical implementation of quantitative bone SPECT remains slow and there is a significant amount of validation required before we get carried away.
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Affiliation(s)
- James C. Ross
- Institute of Nuclear Medicine T05, University College London Hospitals NHS Foundation Trust, 235 Euston Road, London, NW1 2BU UK
| | - Dijana Vilić
- Radiological Sciences Unit, Imperial College Healthcare NHS Trust, London, UK
| | - Tom Sanderson
- Institute of Nuclear Medicine T05, University College London Hospitals NHS Foundation Trust, 235 Euston Road, London, NW1 2BU UK
| | - Stefan Vöö
- Institute of Nuclear Medicine T05, University College London Hospitals NHS Foundation Trust, 235 Euston Road, London, NW1 2BU UK
| | - John Dickson
- Institute of Nuclear Medicine T05, University College London Hospitals NHS Foundation Trust, 235 Euston Road, London, NW1 2BU UK
- Institute of Nuclear Medicine, University College London, London, UK
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Arvola S, Jambor I, Kuisma A, Kemppainen J, Kajander S, Seppänen M, Noponen T. Comparison of standardized uptake values between 99mTc-HDP SPECT/CT and 18F-NaF PET/CT in bone metastases of breast and prostate cancer. EJNMMI Res 2019; 9:6. [PMID: 30680469 PMCID: PMC6346696 DOI: 10.1186/s13550-019-0475-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/15/2019] [Indexed: 11/25/2022] Open
Abstract
Background Despite recent technological advances allowing for quantitative single-photon emission computed tomography (SPECT), quantitative SPECT has not been widely used in the clinical practice. The aim of this study is to evaluate the feasibility of quantitative SPECT for measuring metastatic bone uptake in breast and prostate cancer by comparing standard uptake values (SUVs) measured with 99mTc-HDP SPECT/CT and 18F-NaF PET/CT. Methods Twenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent both 99mTc-HDP SPECT/CT and 18F-NaF PET/CT within 14 days of each other. The SPECT and PET data were reconstructed using ordered-subset expectation-maximization algorithms achieving quantitative images. Metastatic and benign skeletal lesions visible in both data sets were identified, and their maximum, peak, and mean SUVs (SUVmax, SUVpeak, and SUVmean) were determined. SUV ratios (SUVRs) between the lesions and adjacent normal appearing bone were also calculated. Linear regression was used to evaluate the correlations between the SUVs of SPECT and PET and Bland-Altman plots to evaluate the differences between the SUVs and SUVRs of SPECT and PET. Results A total of 231 skeletal lesions, 129 metastatic and 102 benign, were analyzed. All three SUV measures correlated very strongly between SPECT and PET (R2 ≥ 0.80, p < 0.001) when all lesions were included, and the PET SUVs were significantly higher than SPECT SUVs (p < 0.001). The median differences were 21%, 12%, and 19% for SUVmax, SUVpeak, and SUVmean, respectively. On the other hand, the SUVRs were similar between SPECT and PET with median differences of 2%, − 9%, and 2% for SUVRmax, SUVRpeak, and SUVRmean, respectively. Conclusion The strong correlation between SUVs and similar SUVRs of 99mTc-HDP SPECT/CT and 18F-NaF PET/CT demonstrate that SPECT is an applicable tool for clinical quantification of bone metabolism in osseous metastases in breast and prostate cancer patients.
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Affiliation(s)
- Samuli Arvola
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland.
| | - Ivan Jambor
- Department of Diagnostic Radiology, University of Turku, Turku, Finland
| | - Anna Kuisma
- Department of Oncology and Radiotherapy, University of Turku, Turku, Finland
| | | | | | - Marko Seppänen
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland.,Turku PET Centre, Turku, Finland
| | - Tommi Noponen
- Department of Clinical Physiology and Nuclear Medicine, Turku University Hospital, Kiinamyllynkatu 4-8, 20521, Turku, Finland.,Department of Medical Physics, Turku University Hospital, Turku, Finland
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15
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Esquinas PL, Shinto A, Kamaleshwaran KK, Joseph J, Celler A. Biodistribution, pharmacokinetics, and organ-level dosimetry for 188Re-AHDD-Lipiodol radioembolization based on quantitative post-treatment SPECT/CT scans. EJNMMI Phys 2018; 5:30. [PMID: 30523435 PMCID: PMC6283804 DOI: 10.1186/s40658-018-0227-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 08/08/2018] [Indexed: 12/25/2022] Open
Abstract
Background Rhenium-188-labelled-Lipiodol radioembolization is a safe and cost-effective treatment for primary liver cancer. In order to determine correlations between treatment doses and patient response to therapy, accurate patient-specific dosimetry is required. Up to date, the reported dosimetry of 188Re-Lipiodol has been based on whole-body (WB) planar imaging only, which has limited quantitative accuracy. The aim of the present study is to determine the in vivo pharmacokinetics, bio-distribution, and organ-level dosimetry of 188Re-AHDD-Lipiodol radioembolization using a combination of post-treatment planar and quantitative SPECT/CT images. Furthermore, based on the analysis of the pharmacokinetic data, a practical and relatively simple imaging and dosimetry method that could be implemented in clinics for 188Re-AHDD-Lipiodol radioembolization is proposed. Thirteen patients with histologically proven hepatocellular carcinoma underwent 188Re-AHDD-Lipiodol radioembolization. A series of 2–3 WB planar images and one SPECT/CT scan were acquired over 48 h after the treatment. The time-integrated activity coefficients (TIACs, also known as residence-times) and absorbed doses of tumors and organs at risk (OARs) were determined using a hybrid WB/SPECT imaging method. Results Whole-body imaging showed that 188Re-AHDD-Lipiodol accumulated mostly in the tumor and liver tissue but a non-negligible amount of the pharmaceutical was also observed in the stomach, lungs, salivary glands, spleen, kidneys, and urinary bladder. On average, the measured effective half-life of 188Re-AHDD-Lipiodol was 12.5 ± 1.9 h in tumor. The effective half-life in the liver and lungs (the two organs at risk) was 12.6 ± 1.7 h and 12.0 ± 1.9 h, respectively. The presence of 188Re in other organs was probably due to the chemical separation and subsequent release of the free radionuclide from Lipiodol. The average doses per injected activity in the tumor, liver, and lungs were 23.5 ± 40.8 mGy/MBq, 2.12 ± 1.78 mGy/MBq, and 0.11 ± 0.05 mGy/MBq, respectively. The proposed imaging and dosimetry method, consisting of a single SPECT/CT for activity determination followed by 188Re-AHDD-Lipiodol clearance with the liver effective half-life of 12.6 h, resulted in TIACs estimates (and hence, doses) mostly within ± 20% from the reference TIACs (estimated using three WB images and one SPECT/CT). Conclusions The large inter-patient variability of the absorbed doses in tumors and normal tissue in 188Re-HDD-Lipiodol radioembolization patients emphasizes the importance of patient-specific dosimetry calculations based on quantitative post-treatment SPECT/CT imaging. Electronic supplementary material The online version of this article (10.1186/s40658-018-0227-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Pedro L Esquinas
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada. .,Medical Imaging Research Group, Vancouver, British Columbia, Canada.
| | - Ajit Shinto
- Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | | | - Jephy Joseph
- Department of Nuclear Medicine, Kovai Medical Center and Hospital, Coimbatore, Tamil Nadu, India
| | - Anna Celler
- Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada.,Medical Imaging Research Group, Vancouver, British Columbia, Canada
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Del Prete M, Arsenault F, Saighi N, Zhao W, Buteau FA, Celler A, Beauregard JM. Accuracy and reproducibility of simplified QSPECT dosimetry for personalized 177Lu-octreotate PRRT. EJNMMI Phys 2018; 5:25. [PMID: 30318563 PMCID: PMC6186532 DOI: 10.1186/s40658-018-0224-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 08/01/2018] [Indexed: 12/22/2022] Open
Abstract
Background Routine dosimetry is essential for personalized 177Lu-octreotate peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors (NETs), but practical and robust dosimetry methods are needed for wide clinical adoption. The aim of this study was to assess the accuracy and inter-observer reproducibility of simplified dosimetry protocols based on quantitative single-photon emission computed tomography (QSPECT) with a limited number of scanning time points. We also updated our personalized injected activity (IA) prescription scheme. Methods Seventy-nine NET patients receiving 177Lu-octreotate therapy (with a total of 279 therapy cycles) were included in our study. Three-time-point (3TP; days 0, 1, and 3) QSPECT scanning was performed following each therapy administration. Dosimetry was obtained using small volumes of interest activity concentration sampling for the kidney, the bone marrow and the tumor having the most intense uptake. Accuracy of the simplified dosimetry based on two-time-point (2TP; days 1 and 3, monoexponential fit) or a single-time-point (1TPD3; day 3) scanning was assessed, as well as that of hybrid methods based on 2TP for the first cycle and 1TP (day 1 or 3; 2TP/1TPD1 and 2TP/1TPD3, respectively) or no imaging at all (based on IA only; 2TP/no imaging (NI)) for the subsequent induction cycles. The inter-observer agreement was evaluated for the 3TP, 2TP, and hybrid 2TP/1TPD3 methods using a subset of 60 induction cycles (15 patients). The estimated glomerular filtration rate (eGFR), body size descriptors (weight, body surface area (BSA), lean body weight (LBW)), and products of both were assessed for their ability to predict IA per renal absorbed dose at the first cycle. Results The 2TP dosimetry estimates correlated highly with those from the 3TP data for all tissues (Spearman r > 0.99, P < 0.0001) with small relative errors between the methods, particularly for the kidney and the tumor, with median relative errors not exceeding 2% and interdecile ranges spanning over less than 6% and 4%, respectively, for the per-cycle and cumulative estimates. For the bone marrow, the errors were slightly greater (median errors < 6%, interdecile ranges < 14%). Overall, the strength of correlations of the absorbed dose estimates from the simplified methods with those from the 3TP scans tended to progressively decrease, and the relative errors to increase, in the following order: 2TP, 2TP/1TPD3, 1TPD3, 2TP/1TPD1, and 2TP/NI. For the tumor, the 2TP/NI scenario was highly inaccurate due to the interference of the therapeutic response. There was an excellent inter-observer agreement between the three observers, in particular for the renal absorbed dose estimated using the 3TP and 2TP methods, with mean errors lesser than 1% and standard deviations of 5% or lower. The eGFR · LBW and eGFR · BSA products best predicted the ratio of IA to the renal dose (GBq/Gy) for the first cycle (Spearman r = 0.41 and 0.39, respectively; P < 0.001). For the first cycle, the personalized IA proportional to eGFR · LBW or eGFR · BSA decreased the range of delivered renal absorbed dose between patients as compared with the fixed IA. For the subsequent cycles, the optimal personalized IA could be determined based on the prior cycle renal GBq/Gy with an error of less than 21% in 90% of patients. Conclusions A simplified dosimetry protocol based on two-time-point QSPECT scanning on days 1 and 3 post-PRRT provides reproducible and more accurate dose estimates than the techniques relying on a single time point for non-initial or all cycles and results in limited patient inconvenience as compared to protocols involving scanning at later time points. Renal absorbed dose over the 4-cycle induction PRRT course can be standardized by personalizing IA based on the product of eGFR with LBW or BSA for the first cycle and on prior renal dosimetry for the subsequent cycles.
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Affiliation(s)
- Michela Del Prete
- Department of Radiology and Nuclear Medicine and Cancer Research Center, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Branch of CHU de Québec Research Center, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada
| | - Frédéric Arsenault
- Department of Radiology and Nuclear Medicine and Cancer Research Center, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Branch of CHU de Québec Research Center, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada
| | - Nassim Saighi
- Department of Radiology and Nuclear Medicine and Cancer Research Center, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Branch of CHU de Québec Research Center, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada
| | - Wei Zhao
- Medical Imaging Research Group, University of British Columbia, Vancouver, Canada.,Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - François-Alexandre Buteau
- Department of Radiology and Nuclear Medicine and Cancer Research Center, Université Laval, Quebec City, Canada.,Department of Medical Imaging and Oncology Branch of CHU de Québec Research Center, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada
| | - Anna Celler
- Medical Imaging Research Group, University of British Columbia, Vancouver, Canada.,Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| | - Jean-Mathieu Beauregard
- Department of Radiology and Nuclear Medicine and Cancer Research Center, Université Laval, Quebec City, Canada. .,Department of Medical Imaging and Oncology Branch of CHU de Québec Research Center, CHU de Québec - Université Laval, 11 côte du Palais, Quebec City, QC, G1R 2J6, Canada.
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Ramsay SC, Lindsay K, Fong W, Patford S, Younger J, Atherton J. Tc-HDP quantitative SPECT/CT in transthyretin cardiac amyloid and the development of a reference interval for myocardial uptake in the non-affected population. Eur J Hybrid Imaging 2018; 2:17. [PMID: 30175320 PMCID: PMC6105142 DOI: 10.1186/s41824-018-0035-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 05/31/2018] [Indexed: 12/22/2022] Open
Abstract
Background 99mTechnetium-HDP (HDP) bone scans differentiate transthyretin (ATTR) cardiac amyloid from other infiltrative myocardial diseases. These scans are not quantitative and are assessed by comparing myocardial uptake to bone. This study examined whether quantitative HDP SPECT/CT can discriminate individuals with cardiac ATTR from the population without this disease. Methods HDP thoracic xSPECT/CT QUANT (xQUANT) was performed in 29 patients: ATTR cardiac amyloid (n = 6); AL cardiac amyloid (n = 1); other infiltrative myocardial disease (n = 4); no known infiltrative cardiac disease (n = 18). SUVmax measured within volumes of interest for whole heart, ascending aorta blood pool, and specific bones. HDP myocardial uptake calculated as whole heart minus blood pool. Results The cardiac ATTR group had greater HDP myocardial uptake than those with no known infiltrative disease (p = 0.002). AL and other myocardial diseases had uptake indistinguishable from the group with no known infiltrative cardiac disease. The SUVmaxima were sufficiently similar between individuals without cardiac ATTR that a 99% reference interval for HDP uptake could be calculated, providing an upper limit cut point of SUVmax 1.2. Individuals with cardiac ATTR had SUVmax well above this cut point. Conclusion Quantitative SPECT/CT can measure HDP myocardial uptake in individuals with normal hearts and those with cardiac ATTR without recourse to comparison with bone. It enables calculation of a reference interval for HDP myocardial uptake in the population without ATTR cardiac amyloid. Using this reference interval single individuals with cardiac ATTR can be accurately discriminated from the non-affected population. This technique uses a NIST traceable calibration source, potentially allowing development of multicentre clinical decision limits. Its role in disease management warrants further assessment.
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Affiliation(s)
- Stuart C Ramsay
- 1Department of Nuclear Medicine and Specialised PET Service, Ned Hanlon Building, Royal Brisbane and Women's Hospital (RBWH), Herston, QLD 4029 Australia.,2School of Medicine, James Cook University, Douglas, QLD 4811 Australia
| | - Karen Lindsay
- 1Department of Nuclear Medicine and Specialised PET Service, Ned Hanlon Building, Royal Brisbane and Women's Hospital (RBWH), Herston, QLD 4029 Australia
| | - William Fong
- 1Department of Nuclear Medicine and Specialised PET Service, Ned Hanlon Building, Royal Brisbane and Women's Hospital (RBWH), Herston, QLD 4029 Australia
| | - Shaun Patford
- 1Department of Nuclear Medicine and Specialised PET Service, Ned Hanlon Building, Royal Brisbane and Women's Hospital (RBWH), Herston, QLD 4029 Australia
| | - John Younger
- 3Department of Cardiology RBWH, Herston, QLD 4029 Australia
| | - John Atherton
- 3Department of Cardiology RBWH, Herston, QLD 4029 Australia.,4School of Clinical Medicine, Faculty of Medicine, University of Queensland, Heston, QLD 4006 Australia
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Porter CA, Bradley KM, Hippeläinen ET, Walker MD, McGowan DR. Phantom and clinical evaluation of the effect of full Monte Carlo collimator modelling in post-SIRT yttrium-90 Bremsstrahlung SPECT imaging. EJNMMI Res 2018; 8:7. [PMID: 29356993 PMCID: PMC5778088 DOI: 10.1186/s13550-018-0361-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/10/2018] [Indexed: 01/06/2023] Open
Abstract
Background Post-therapy SPECT/CT imaging of 90Y microspheres delivered to hepatic malignancies is difficult, owing to the continuous, high-energy Bremsstrahlung spectrum emitted by 90Y. This study aimed to evaluate the utility of a commercially available software package (HybridRecon, Hermes Medical Solutions AB) which incorporates full Monte Carlo collimator modelling. Analysis of image quality was performed on both phantom and clinical images in order to ultimately provide a recommendation of an optimum reconstruction for post-therapy 90Y microsphere SPECT/CT imaging. A 3D-printed anthropomorphic liver phantom was filled with 90Y with a sphere-to-background ratio of 4:1 and imaged on a GE Discovery 670 SPECT/CT camera. Datasets were reconstructed using ordered-subsets expectation maximization (OSEM) 1–7 iterations in order to identify the optimal OSEM reconstruction (5 iterations, 15 subsets). Quantitative analysis was subsequently carried out on phantom datasets obtained using four reconstruction algorithms: the default OSEM protocol (2 iterations, 10 subsets) and the optimised OSEM protocol, both with and without full Monte Carlo collimator modelling. The quantitative metrics contrast recovery (CR) and background variability (BV) were calculated. The four algorithms were then used to retrospectively reconstruct 10 selective internal radiation therapy (SIRT) patient datasets which were subsequently blind scored for image quality by a consultant radiologist. Results The optimised OSEM reconstruction (5 iterations, 15 subsets with full MC collimator modelling) increased the CR by 42% (p < 0.001) compared to the default OSEM protocol (2 iterations, 10 subsets). The use of full Monte Carlo collimator modelling was shown to further improve CR by 14% (30 mm sphere, CR = 90%, p < 0.05). The consultant radiologist had a significant preference for the optimised OSEM over the default OSEM protocol (p < 0.001), with the optimised OSEM being the favoured reconstruction in every one of the 10 clinical cases presented. Conclusions OSEM (5 iterations, 15 subsets) with full Monte Carlo collimator modelling is quantitatively the optimal image reconstruction for post-SIRT 90Y Bremsstrahlung SPECT/CT imaging. The use of full Monte Carlo collimator modelling for correction of image-degrading effects significantly increases contrast recovery without degrading clinical image quality.
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Affiliation(s)
- Charlotte A Porter
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 7LE, UK.
| | - Kevin M Bradley
- Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Eero T Hippeläinen
- HUS Medical Imaging Centre, Clinical Physiology and Nuclear Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Matthew D Walker
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 7LE, UK
| | - Daniel R McGowan
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, OX3 7LE, UK.,Department of Oncology, University of Oxford, Old Road Campus Research Building, Oxford, UK
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19
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Thøgersen KF, Simonsen JA, Hvidsten S, Gerke O, Jacobsen S, Høilund-Carlsen PF, Buch-Olsen KM, Diederichsen LP. Quantitative 3D scintigraphy shows increased muscular uptake of pyrophosphate in idiopathic inflammatory myopathy. EJNMMI Res 2017; 7:97. [PMID: 29222707 PMCID: PMC5722781 DOI: 10.1186/s13550-017-0348-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Nuclear imaging is increasingly being used in the diagnostic work-up of idiopathic inflammatory myopathy (IIM). Increased muscular uptake of technetium-99m-pyrophosphate (99mTc-PYP) has hitherto been assessed qualitatively by planar scintigraphy. We set out to perform quantitative tomographic scintigraphy in IIM. RESULTS Ninety IIM patients and 48 control subjects underwent 99mTc-PYP single-photon emission computed tomography (SPECT)/CT of the upper and lower body. Scans were evaluated visually by an intensity score (1-4) and quantitatively by the mean standardized uptake value (SUVmean) in thigh muscles after semi-automated segmentation of these. Furthermore, a SUVmean gradient down along the thighs was determined by linear regression of the slice-by-slice activity. Interobserver analyses were performed on qualitative evaluations. Compared to controls, patients more often had a high intensity score (p < 0.0001), but interobserver analyses revealed only moderate agreement. The thigh muscular 99mTc-PYP activity (SUVmean) was 60% higher in patients than in controls, p < 0.0001, albeit with a wide range. There was an activity gradient down the thigh muscle, the proximal tracer uptake being highest, and this gradient was steeper in patients than in controls; the activity decreased by 0.00024 and 0.00010 SUVmean mm-1, respectively, along the thighs. CONCLUSIONS The muscular uptake of 99mTc-PYP was significantly higher in patients than in healthy controls by qualitative and quantitative assessment. The tracer uptake was higher in the proximal than in the distal part of the thigh muscle, and SUVmean gradients differed between groups. Hence, tomographic nuclear imaging allowing for quantification of the 99mTc-PYP uptake might contribute to the diagnosis of IIM, and SPECT/CT of the lower body might suffice.
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Affiliation(s)
- Karin Folmer Thøgersen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Department of Rheumatology, Odense University Hospital, Odense, Denmark
| | - Jane Angel Simonsen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.
| | - Svend Hvidsten
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark
| | - Oke Gerke
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Centre of Health Economics Research, University of Southern Denmark, Odense, Denmark
| | - Søren Jacobsen
- Copenhagen Lupus and Vasculitis Clinic, Center for Rheumatology and Spine Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Poul Flemming Høilund-Carlsen
- Department of Nuclear Medicine, Odense University Hospital, Kløvervænget 47, 5000, Odense, Denmark.,Clinical Institute, University of Southern Denmark, Odense, Denmark
| | | | - Louise Pyndt Diederichsen
- Department of Rheumatology, Odense University Hospital, Odense, Denmark.,Clinical Institute, University of Southern Denmark, Odense, Denmark
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20
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Li T, Wu NY, Song N, Mok GSP. Evaluation of sequential SPECT and CT for targeted radionuclide therapy dosimetry. Ann Nucl Med 2017; 32:34-43. [PMID: 29143283 DOI: 10.1007/s12149-017-1218-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/08/2017] [Indexed: 12/22/2022]
Abstract
PURPOSE In targeted radionuclide therapy (TRT), a prior knowledge of the absorbed dose biodistribution is essential for pre-therapy treatment planning. Previously, we showed that non-rigid organ-by-organ registration in sequential quantitative SPECT images improved dose estimation. This study aims to investigate if sequential CT can further improve TRT dosimetric accuracy. METHODS We simulated SPECT/CT acquisitions at 1, 12, 24, 72 and 144 h In-111 Zevalin post-injection using an analytical MEGP projector, modeling attenuation, scatter and collimator-detector response. We later recruited a patient injected with 222 MBq In-111 DTPAOC imaged at 3 SPECT/CT sessions for clinical evaluations. Four registration schemes were evaluated: whole-body-based registration performed on sequential (1) SPECT (WB-SPECT) or (2) CT (WB-CT) images; organ-based registration applied on organs individually segmented from sequential (3) SPECT (O-SPECT) or (4) CT (O-CT) images. Voxel-by-voxel integration was performed followed by Y-90 voxel-S-kernel convolution. Organ-absorbed doses, iso-dose curves, dose-volume histograms (DVHs) were generated for targeted organs for analysis. RESULTS In simulation study, organ-absorbed dose errors were (- 8.66 ± 2.83)%, (- 2.51 ± 3.69)%, (- 9.23 ± 3.28)%, (- 7.17 ± 2.53)% for liver, (- 14.81 ± 4.91)%, (- 3.60 ± 4.37)%, (- 18.13 ± 4.44)%, (- 11.34 ± 4.22)% for spleen, for O-SPECT, O-CT, WB-SPECT and WB-CT registrations, respectively. For all organs, O-CT showed superior results. Results of iso-dose contour, DVHs were in accordance with the organ-absorbed doses. In clinical studies, the results were also consistent which showed O-CT method deviated the most from the result with no registration. CONCLUSIONS We conclude that if both sequential SPECT/CT scans are available, CT organ-based registration method can more effectively improve the 3D dose estimation. Sequential low-dose CT scans might be considered to be included in the standard TRT protocol.
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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
| | - Nien-Yun Wu
- Department of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan, Republic of China.,Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
| | - Na Song
- Department of Nuclear Medicine, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York, 10461, USA
| | - 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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21
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Matsutomo N, Matsumoto S, Yamamoto T, Sato E. Validation of a calibration method using the cross-calibration factor and system planar sensitivity in quantitative single-photon emission computed tomography imaging. Radiol Phys Technol 2017; 10:439-445. [PMID: 28822095 DOI: 10.1007/s12194-017-0416-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/14/2017] [Accepted: 08/15/2017] [Indexed: 11/28/2022]
Abstract
The present study aimed to validate the absolute quantitative accuracy of a calibration method for single-photon emission computed tomography (SPECT) using cross-calibration factor (CCF)- and system sensitivity-based calibration methods. The CCF obtained with different reconstruction parameters was evaluated using a cylindrical phantom (diameter 20 cm, height 20 cm). SPECT images were acquired with a positron emission tomography/computed tomography (CT) phantom. Subsequently, they were reconstructed by using ordered subset expectation maximization with resolution recovery, scatter, and CT-based attenuation correction. All reconstructed SPECT counts were converted to activity concentrations based on the CCF and system planar sensitivity. We placed 12 circular regions of interest, 37 mm in diameter, on the phantom background, and the converted activity concentration and relative measurement error were assessed. The CCF obtained using a cylindrical phantom was affected by the iterative update number and post-smoothing filter function. The activity concentration calibrated using the CCF showed over- and underestimation. However, the activity concentration obtained from the system planar sensitivity was similar to that gained using the phantom. The values obtained using the system planar sensitivity were within 10% of the activity concentrations obtained with the phantom. These findings demonstrated that the calibration method using system planar sensitivity provides accurate quantification within 10% of the true activity concentration. Further clinical examination is required to validate the present results.
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Affiliation(s)
- Norikazu Matsutomo
- Department of Medical Radiological Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi, Tokyo, 181-8612, Japan.
| | - Saki Matsumoto
- Department of Radiology, Kyorin University Hospital, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan
| | - Tomoaki Yamamoto
- Department of Medical Radiological Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi, Tokyo, 181-8612, Japan
| | - Eisuke Sato
- Department of Medical Radiological Technology, Faculty of Health Sciences, Kyorin University, 5-4-1 Shimorenjaku, Mitaka-shi, Tokyo, 181-8612, Japan
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22
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Jha AK, Song N, Caffo B, Frey EC. Objective evaluation of reconstruction methods for quantitative SPECT imaging in the absence of ground truth. Proc SPIE Int Soc Opt Eng 2015; 9416:94161K. [PMID: 26430292 DOI: 10.1117/12.2081286] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Quantitative single-photon emission computed tomography (SPECT) imaging is emerging as an important tool in clinical studies and biomedical research. There is thus a need for optimization and evaluation of systems and algorithms that are being developed for quantitative SPECT imaging. An appropriate objective method to evaluate these systems is by comparing their performance in the end task that is required in quantitative SPECT imaging, such as estimating the mean activity concentration in a volume of interest (VOI) in a patient image. This objective evaluation can be performed if the true value of the estimated parameter is known, i.e. we have a gold standard. However, very rarely is this gold standard known in human studies. Thus, no-gold-standard techniques to optimize and evaluate systems and algorithms in the absence of gold standard are required. In this work, we developed a no-gold-standard technique to objectively evaluate reconstruction methods used in quantitative SPECT when the parameter to be estimated is the mean activity concentration in a VOI. We studied the performance of the technique with realistic simulated image data generated from an object database consisting of five phantom anatomies with all possible combinations of five sets of organ uptakes, where each anatomy consisted of eight different organ VOIs. Results indicate that the method provided accurate ranking of the reconstruction methods. We also demonstrated the application of consistency checks to test the no-gold-standard output.
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Affiliation(s)
- Abhinav K Jha
- Division of Medical Imaging Physics, Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Na Song
- Division of Nuclear Medicine, Department of Radiology, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, USA
| | - Brian Caffo
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Eric C Frey
- Division of Medical Imaging Physics, Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, USA
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