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Daisaki H, Kubota C, Ishikawa K, Sato M, Yasumoto Y, Fukai S, Sakashita T. [Validation of Quantitative Accuracy and Variability in 177Lu Imaging Using Monte Carlo Simulation]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2024; 80:593-604. [PMID: 38569841 DOI: 10.6009/jjrt.2024-1451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
PURPOSE To predict side effects and optimize injection doses in the dosimetry of 177Lu imaging, highly accurate quantitative SPECT images are required. Monte Carlo simulations were performed to verify the accuracy and variability of quantitative values for 177Lu imaging under various imaging conditions. METHODS SPECT data of NEMA body phantom were assumed to simulate intrahepatic tumors 6 h after administration of 7.4 GBq of 177Lu-Dotatate. SPECT data were acquired using the SIMIND program with different combinations of collimators and energy windows. For variability evaluation, 30 SPECT images with Poisson noise were generated for each acquisition time. The relative error was evaluated for accuracy evaluation, and the coefficient of variation was estimated for variability evaluation. RESULTS The accuracy of BG quantification was less than 10% relative error. The accuracy of hot sphere quantification was highest with the combination of MEGP and an energy window of 208 keV±10%. However, the accuracy of hot sphere quantification decreased significantly with decreasing hot sphere diameter. Variability varied with imaging conditions and improved with longer acquisition time. CONCLUSION Monte Carlo simulations revealed the accuracy and variability of quantitative values for each SPECT imaging condition for 177Lu imaging.
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Affiliation(s)
- Hiromitsu Daisaki
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Chihiro Kubota
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Kazuma Ishikawa
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | - Mitsuru Sato
- Department of Radiological Technology, Gunma Prefectural College of Health Sciences
| | | | - Shohei Fukai
- Department of Nuclear Medicine, Cancer Institute Hospital of Japanese Foundation for Cancer Research
| | - Tetsuya Sakashita
- Department of Quantum-Applied Biosciences, Takasaki Institute for Advanced Quantum Science, National Institutes for Quantum Science and Technology
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Gawel J, Rogulski Z. The Challenge of Single-Photon Emission Computed Tomography Image Segmentation in the Internal Dosimetry of 177Lu Molecular Therapies. J Imaging 2024; 10:27. [PMID: 38276319 PMCID: PMC10817423 DOI: 10.3390/jimaging10010027] [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: 11/27/2023] [Revised: 01/03/2024] [Accepted: 01/05/2024] [Indexed: 01/27/2024] Open
Abstract
The aim of this article is to review the single photon emission computed tomography (SPECT) segmentation methods used in patient-specific dosimetry of 177Lu molecular therapy. Notably, 177Lu-labelled radiopharmaceuticals are currently used in molecular therapy of metastatic neuroendocrine tumours (ligands for somatostatin receptors) and metastatic prostate adenocarcinomas (PSMA ligands). The proper segmentation of the organs at risk and tumours in targeted radionuclide therapy is an important part of the optimisation process of internal patient dosimetry in this kind of therapy. Because this is the first step in dosimetry assessments, on which further dose calculations are based, it is important to know the level of uncertainty that is associated with this part of the analysis. However, the robust quantification of SPECT images, which would ensure accurate dosimetry assessments, is very hard to achieve due to the intrinsic features of this device. In this article, papers on this topic were collected and reviewed to weigh up the advantages and disadvantages of the segmentation methods used in clinical practice. Degrading factors of SPECT images were also studied to assess their impact on the quantification of 177Lu therapy images. Our review of the recent literature gives an insight into this important topic. However, based on the PubMed and IEEE databases, only a few papers investigating segmentation methods in 177Lumolecular therapy were found. Although segmentation is an important step in internal dose calculations, this subject has been relatively lightly investigated for SPECT systems. This is mostly due to the inner features of SPECT. What is more, even when studies are conducted, they usually utilise the diagnostic radionuclide 99mTc and not a therapeutic one like 177Lu, which could be of concern regarding SPECT camera performance and its overall outcome on dosimetry.
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Affiliation(s)
- Joanna Gawel
- Faculty of Chemistry, University of Warsaw, 02-093 Warsaw, Poland
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Danieli R, Stella M, Leube J, Tran-Gia J, Marin C, Uribe CF, Vanderlinden B, Reynaert N, Flamen P, Levillain H. Quantitative 177Lu SPECT/CT imaging for personalized dosimetry using a ring-shaped CZT-based camera. EJNMMI Phys 2023; 10:64. [PMID: 37853247 PMCID: PMC10584798 DOI: 10.1186/s40658-023-00586-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/12/2023] [Indexed: 10/20/2023] Open
Abstract
BACKGROUND Dosimetry after radiopharmaceutical therapy with 177Lu (177Lu-RPT) relies on quantitative SPECT/CT imaging, for which suitable reconstruction protocols are required. In this study, we characterized for the first time the quantitative performance of a ring-shaped CZT-based camera using two different reconstruction algorithms: an ordered subset expectation maximization (OSEM) and a block sequential regularized expectation maximization (BSREM) combined with noise reduction regularization. This study lays the foundations for the definition of a reconstruction protocol enabling accurate dosimetry for patients treated with 177Lu-RPT. METHODS A series of 177Lu-filled phantoms were acquired on a StarGuide™ (GE HealthCare), with energy and scatter windows centred at 208 (± 6%) keV and 185 (± 5%) keV, respectively. Images were reconstructed with the manufacturer implementations of OSEM (GE-OSEM) and BSREM (Q.Clear) algorithms, and various combinations of iterations and subsets. Additionally, the manufacturer-recommended Q.Clear-based reconstruction protocol was evaluated. Quantification accuracy, measured as the difference between the SPECT-based and the radionuclide calibrator-based activity, and noise were evaluated in a large cylinder. Recovery coefficients (RCs) and spatial resolution were assessed in a NEMA IEC phantom with sphere inserts. The reconstruction protocols considered suitable for clinical applications were tested on a cohort of patients treated with [177Lu]Lu-PSMA-I&T. RESULTS The accuracy of the activity from the cylinder, although affected by septal penetration, was < 10% for all reconstructions. Both algorithms featured improved spatial resolution and higher RCs with increasing updates at the cost of noise build-up, but Q.Clear outperformed GE-OSEM in reducing noise accumulation. When the reconstruction parameters were carefully selected, similar values for noise (~0.15), spatial resolution (~1 cm) and RCs were found, irrespective of the reconstruction algorithm. Analogue results were found in patients. CONCLUSIONS Accurate activity quantification is possible when imaging 177Lu with StarGuide™. However, the impact of septal penetration requires further investigations. GE-OSEM is a valid alternative to the recommended Q.Clear reconstruction algorithm, featuring comparable performances assessed on phantoms and patients.
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Affiliation(s)
- Rachele Danieli
- Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium.
- Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium.
| | - Martina Stella
- Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
- GE HealthCare, Diegem, Belgium
| | - Julian Leube
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University Hospital Würzburg, Würzburg, Germany
| | - Clementine Marin
- Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | | | - Bruno Vanderlinden
- Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium
- Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Nick Reynaert
- Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium
- Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Patrick Flamen
- Department of Nuclear Medicine, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Hugo Levillain
- Department of Medical Physics, Institut Jules Bordet, Hôpital Universitaire de Bruxelles (H.U.B), Université Libre de Bruxelles (ULB), Brussels, Belgium
- Radiophysics and MRI Physics Laboratory, Université Libre de Bruxelles (ULB), Brussels, Belgium
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Bednarz B. Theranostics and Patient-Specific Dosimetry. Semin Radiat Oncol 2023; 33:317-326. [PMID: 37331786 PMCID: PMC10414757 DOI: 10.1016/j.semradonc.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Radiopharmaceutical therapy (RPT) is an invigorated form of cancer therapy that systemically delivers targeted radioactive drugs to cancer cells. Theranostics is a type of RPT that utilizes imaging, either of the RPT drug directly or a companion diagnostic, to inform whether a patient will benefit from the treatment. Given the ability to image the drug onboard theranostic treatments also lends itself readily to patient-specific dosimetry, which is a physics-based process that determines the overall absorbed dose burden to healthy organs and tissues and tumors in patients. While companion diagnostics identify who will benefit from RPT treatments, dosimetry determines how much activity these beneficiaries can receive to maximize therapeutic efficacy. Clinical data is starting to accrue suggesting tremendous benefits when dosimetry is performed for RPT patients. RPT dosimetry, which was once performed by florid and often inaccurate workflows, can now be performed more efficiently and accurately with FDA-cleared dosimetry software. Therefore, there is no better time for the field of oncology to adopt this form of personalize medicine to improve outcomes for cancer patients.
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Affiliation(s)
- Bryan Bednarz
- Department of Medical Physics, University of Wisconsin - Madison, Madison, WI.
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Kovan B, Demir B, Işık EG, Has Şimşek D, Özkan ZG, Kuyumcu S, Türkmen C, Şanlı Y. An anthropomorphic body phantom for the determination of calibration factor in radionuclide treatment dosimetry. RADIATION PROTECTION DOSIMETRY 2023:ncad176. [PMID: 37334429 PMCID: PMC10372715 DOI: 10.1093/rpd/ncad176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 02/02/2023] [Accepted: 05/18/2023] [Indexed: 06/20/2023]
Abstract
The aim of this study is to create an inhomogeneous human-like phantom, whose attenuation and scattering effects are similar to the human body, as an alternative to the homogeneous phantoms traditionally used in calibration factor (CF) determination. The phantom was designed to include the thorax, abdomen and upper pelvis regions sized to represent a 75-kg male with a body mass index of 25. Measurements using Lu-177 with 50- and 100-mL lesion volumes were performed using inhomogeneous anthropomorphic body phantom (ABP) and homogeneous NEMA PET body phantom. There was a difference of 5.7% of Calibration Factor including attenuation and scatter effect between ABP and NEMA PET body phantom. Because it better reflects the attenuation and scatter effect, it is recommended to use a human-like inhomogeneous phantom for determination of CF instead of a homogeneous phantom.
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Affiliation(s)
- Bilal Kovan
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Bayram Demir
- Science Faculty, Department of Physics, Istanbul University, Fatih34080, Turkey
| | - Emine Göknur Işık
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Duygu Has Şimşek
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Zeynep Gözde Özkan
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Sekan Kuyumcu
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Cüneyt Türkmen
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
| | - Yasemin Şanlı
- Istanbul Medical Faculty, Department of Nuclear Medicine, Istanbul University, Fatih 34080, Turkey
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EANM dosimetry committee recommendations for dosimetry of 177Lu-labelled somatostatin-receptor- and PSMA-targeting ligands. Eur J Nucl Med Mol Imaging 2022; 49:1778-1809. [PMID: 35284969 PMCID: PMC9015994 DOI: 10.1007/s00259-022-05727-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/13/2022] [Indexed: 12/25/2022]
Abstract
The purpose of the EANM Dosimetry Committee is to provide recommendations and guidance to scientists and clinicians on patient-specific dosimetry. Radiopharmaceuticals labelled with lutetium-177 (177Lu) are increasingly used for therapeutic applications, in particular for the treatment of metastatic neuroendocrine tumours using ligands for somatostatin receptors and prostate adenocarcinoma with small-molecule PSMA-targeting ligands. This paper provides an overview of reported dosimetry data for these therapies and summarises current knowledge about radiation-induced side effects on normal tissues and dose-effect relationships for tumours. Dosimetry methods and data are summarised for kidneys, bone marrow, salivary glands, lacrimal glands, pituitary glands, tumours, and the skin in case of radiopharmaceutical extravasation. Where applicable, taking into account the present status of the field and recent evidence in the literature, guidance is provided. The purpose of these recommendations is to encourage the practice of patient-specific dosimetry in therapy with 177Lu-labelled compounds. The proposed methods should be within the scope of centres offering therapy with 177Lu-labelled ligands for somatostatin receptors or small-molecule PSMA.
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Kennedy J, Chicheportiche A, Keidar Z. Quantitative SPECT/CT for dosimetry of peptide receptor radionuclide therapy. Semin Nucl Med 2021; 52:229-242. [PMID: 34911637 DOI: 10.1053/j.semnuclmed.2021.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Neuroendocrine tumors (NETs) are uncommon malignancies of increasing incidence and prevalence. As these slow growing tumors usually overexpress somatostatin receptors (SSTRs), the use of 68Ga-DOTA-peptides (gallium-68 chelated with dodecane tetra-acetic acid to somatostatin), which bind to the SSTRs, allows for PET based imaging and selection of patients for peptide receptor radionuclide therapy (PRRT). PRRT with radiolabeled somatostatin analogues such as 177Lu-DOTATATE (lutetium-177-[DOTA,Tyr3]-octreotate), is mainly used for the treatment of metastatic or inoperable NETs. However, PRRT is generally administered at a fixed injected activity in order not to exceed dose limits in critical organs, which is suboptimal given the variability in radiopharmaceutical uptake among patients. Advances in SPECT (single photon emission computed tomography) imaging enable the absolute quantitative measure of the true radiopharmaceutical distribution providing for PRRT dosimetry in each patient. Personalized PRRT based on patient-specific dosimetry could improve therapeutic efficacy by optimizing effective tumor absorbed dose while limiting treatment related radiotoxicity.
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Affiliation(s)
- John Kennedy
- Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, Israel; B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
| | - Alexandre Chicheportiche
- Department of Nuclear Medicine and Biophysics, Hadassah Medical Organization and Faculty of Medicine, Hebrew University of Jerusalem, Israel
| | - Zohar Keidar
- Department of Nuclear Medicine, Rambam Health Care Campus, Haifa, Israel; B. Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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Liu X, Liu H, Cheng L, Wu J, Bao T, Yao R, Liu Y. A 3-dimensional stationary cascade gamma-ray coincidence imager. Phys Med Biol 2021; 66. [PMID: 34666327 DOI: 10.1088/1361-6560/ac311b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 10/19/2021] [Indexed: 11/12/2022]
Abstract
Objective.For certain radionuclides that decay through emitting two or more gamma photons consecutively within a short time interval-called cascade gamma-rays, the location where a radiopharmaceutical molecule emits cascade gamma-rays can be identified through coincidence detection of the photons. If each cascade photon is detected through a collimation mechanism, the location of the molecule can be inferred from the intersection of the back-projections of the two photons.Approach.In this work, we report the design and evaluation of a three-dimensional stationary imager based on this concept for imaging distributions of cascade-emitting radionuclides in radiopharmaceutical therapy. The imager was composed of two gamma-ray cameras assembled in an L-shape. Both cameras were NaI(Tl) scintillator based, one with a multi-slit collimator, the other with a multi-pinhole collimator. The field of view (FOV) was 100 mm (∅) × 100 mm (L). Based on the unique characteristics of the cascade coincidence events, we used a direct back-projection algorithm to reconstruct point source images for assessing the imager's intrinsic spatial resolution and the standard maximum likelihood expectation maximization algorithm for reconstructing phantom images.Main results.We evaluated the performance of the imager in both simulated and prototype form with radionuclide177Lu (cascade photon emitter). On the simulated imager, the coincidence detection efficiency at the center of FOV was 3.85 × 10-6, the spatial resolution was 7.0 mm. On the prototype imager, the corresponding values were 3.20 × 10-6and 6.7 mm, respectively. Simulated hot-rod and experimental cardiac phantom studies demonstrate the first three-dimensional cascade gamma coincidence imager is fully functional.
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Affiliation(s)
- Xiao Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Ministry of Education (Tsinghua University), Beijing 100084, People's Republic of China
| | - Hui Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Ministry of Education (Tsinghua University), Beijing 100084, People's Republic of China
| | - Li Cheng
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Ministry of Education (Tsinghua University), Beijing 100084, People's Republic of China
| | - Jing Wu
- Center for Advanced Quantum Studies and Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Tianwei Bao
- Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Rutao Yao
- Department of Nuclear Medicine, University at Buffalo, State University of New York, NY 14214, United States of America
| | - Yaqiang Liu
- Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.,Key Laboratory of Particle & Radiation Imaging, Ministry of Education (Tsinghua University), Beijing 100084, People's Republic of China
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Quantitative SPECT (QSPECT) at high count rates with contemporary SPECT/CT systems. EJNMMI Phys 2021; 8:73. [PMID: 34718900 PMCID: PMC8557232 DOI: 10.1186/s40658-021-00421-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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Brosch-Lenz J, Yousefirizi F, Zukotynski K, Beauregard JM, Gaudet V, Saboury B, Rahmim A, Uribe C. Role of Artificial Intelligence in Theranostics:: Toward Routine Personalized Radiopharmaceutical Therapies. PET Clin 2021; 16:627-641. [PMID: 34537133 DOI: 10.1016/j.cpet.2021.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We highlight emerging uses of artificial intelligence (AI) in the field of theranostics, focusing on its significant potential to enable routine and reliable personalization of radiopharmaceutical therapies (RPTs). Personalized RPTs require patient-specific dosimetry calculations accompanying therapy. Additionally we discuss the potential to exploit biological information from diagnostic and therapeutic molecular images to derive biomarkers for absorbed dose and outcome prediction; toward personalization of therapies. We try to motivate the nuclear medicine community to expand and align efforts into making routine and reliable personalization of RPTs a reality.
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Affiliation(s)
- Julia Brosch-Lenz
- Department of Integrative Oncology, BC Cancer Research Institute, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Fereshteh Yousefirizi
- Department of Integrative Oncology, BC Cancer Research Institute, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada
| | - Katherine Zukotynski
- Department of Medicine and Radiology, McMaster University, 1200 Main Street West, Hamilton, Ontario L9G 4X5, Canada
| | - Jean-Mathieu Beauregard
- Department of Radiology and Nuclear Medicine, Cancer Research Centre, Université Laval, 2325 Rue de l'Université, Québec City, Quebec G1V 0A6, Canada; Department of Medical Imaging, Research Center (Oncology Axis), CHU de Québec - Université Laval, 2325 Rue de l'Université, Québec City, Quebec G1V 0A6, Canada
| | - Vincent Gaudet
- Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
| | - Babak Saboury
- Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA; Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA; Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Arman Rahmim
- Department of Integrative Oncology, BC Cancer Research Institute, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada; Department of Radiology, University of British Columbia, 11th Floor, 2775 Laurel St, Vancouver, British Columbia V5Z 1M9, Canada; Department of Physics, University of British Columbia, 325 - 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1, Canada
| | - Carlos Uribe
- Department of Radiology, University of British Columbia, 11th Floor, 2775 Laurel St, Vancouver, British Columbia V5Z 1M9, Canada; Department of Functional Imaging, BC Cancer, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada.
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Sekikawa Y, Funada K, Akamatsu G, Himuro K, Takahashi A, Baba S, Sasaki M. Monte Carlo simulation of the acquisition conditions for 177Lu molecular imaging of hepatic tumors. Ann Nucl Med 2021; 35:823-833. [PMID: 34057655 DOI: 10.1007/s12149-021-01620-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 04/21/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To examine the impact of acquisition time on Lutetium-177 (177Lu) single-photon emission computed tomography (SPECT) images using Monte Carlo simulation. METHODS A gamma camera simulation based on the Monte Carlo method was performed to produce SPECT images. The phantom was modeled on a NEMA IEC BODY phantom including six spheres as tumors. After the administration of 7.4 GBq of 177Lu, radioactivity concentrations of the tumor/liver at 6, 24, and 72 h after administration were set to 1.85/0.201, 2.12/0.156, and 1.95/0.117 MBq/mL, respectively. In addition, the radioactivity concentrations of the tumor at 72 h after administration varied by 1/2, 1/4, and 1/8 when comparison was made. Acquisition times examined were 1.2, 1.5, 2, 3, 6, and 12 min. To assess the impact of collimators, SPECT data acquired at 72 h after the administration using six collimators of low-energy high-resolution (LEHR), extended low-energy general-purpose (ELEGP), medium-energy, and general-purpose (MEGP-1, MEGP-2, and MEGP-3) and high-energy general-purpose (HEGP) were examined. After prefiltering using a Butterworth filter, projection images were reconstructed using ordered subset expectation maximization. The detected photons were classified into direct rays, scattered rays, penetrating rays, and characteristic X-rays from lead. The image quality was evaluated through visual assessment, and physical assessment of contrast recovery coefficient (CRC) and contrast-to-noise ratio (CNR). In this study, the CNR threshold for detectability was assumed to be 5.0. RESULTS To compare collimators, the highest sensitivity was observed with ELEGP, followed by LEHR and MEGP-1. The highest ratio of direct ray was also observed in ELEGP followed by MEGP-1. In comparison of the radioactivity concentration ratios of tumor/liver, CRC and CNR were significantly decreased with smaller radioactivity concentration ratios. This effect was greater with larger spheres. According to the visual assessment, the acquisition time of 6, 6, and 3 min or longer was required using ELEGP collimator at 6, 24, and 72 h after administration, respectively. Physical assessment based on CNR and CRC also suggested that 6, 6, and 3 min or longer acquisition time was necessary at 6, 24, and 72 h after administration. CONCLUSION 177Lu-SPECT images generated via the Monte Carlo simulation suggested that the recommended acquisition time was 6 min or longer at 6 and 24 h and 3 min or longer at 72 h after administration.
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Affiliation(s)
- Yuya Sekikawa
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
- Department of Radiological Technology, Faculty of Fukuoka Medical Technology, Teikyo University, 6-22 Misakimachi, Omuta, Fukuoka, 836-8505, Japan
| | - Keita Funada
- Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Go Akamatsu
- National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1 Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Kazuhiko Himuro
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Akihiko Takahashi
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
| | - Shingo Baba
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Masayuki Sasaki
- Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Monserrat Fuertes T, González García F, Peinado Montes M, Domínguez Grande M, Martín Fernández N, Gómez de Iturriaga Piña A, Mínguez Gabiña P. Description of the methodology for dosimetric quantification in treatments with 177Lu-DOTATATE. Rev Esp Med Nucl Imagen Mol 2021. [DOI: 10.1016/j.remnie.2021.03.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Monserrat Fuertes T, González García FM, Peinado Montes MÁ, Domínguez Grande ML, Martín Fernández N, Gómez de Iturriaga Piña A, Mínguez Gabiña P. Description of the methodology for dosimetric quantification in treatments with 177Lu-DOTATATE. Rev Esp Med Nucl Imagen Mol 2021; 40:167-178. [PMID: 33811003 DOI: 10.1016/j.remn.2021.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 11/28/2022]
Abstract
Implementation of dosimetry calculations in the daily practice of Nuclear Medicine Departments is, at this time, a controversial issue, partly due to the lack of a standardized methodology that is accepted by all interested parties (patients, nuclear medicine physicians and medical physicists). However, since the publication of RD 601/2019 there is a legal obligation to implement it, despite the fact that it is a complex and high resource consumption procedure. The aim of this article is to review the theoretical bases of in vivo dosimetry in treatments with 177Lu-DOTATATE. The exposed methodology is the one proposed by the MIRD Committee (Medical Internal Radiation Dose) of the SNMMI (Society of Nuclear Medicine & Molecular Imaging). According to this method, the absorbed dose is obtained as the product of 2factors: the time-integrated activity of the radiopharmaceutical present in a source region and a geometrical factor S. This approach, which a priori seems simple, in practice requires several SPECT/CT acquisitions, several measurements of the whole body activity and taking several blood samples, as well as hours of image processing and computation. The systematic implementation of these calculations, in all the patients we treat, will allow us to obtain homogeneous data to correlate the absorbed doses in the lesions with the biological effect of the treatment. The final purpose of the dosimetry calculations is to be able to maximize the therapeutic effect in the lesions, controlling the radiotoxicity in the organs at risk.
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Affiliation(s)
- T Monserrat Fuertes
- Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Central de Asturias, Oviedo, Asturias, España; Departamento de Cirugía, Radiología y Medicina Física, UPV/EHU, Leioa, Bizkaia, España.
| | - F M González García
- Servicio de Medicina Nuclear, Hospital Universitario Central de Asturias, Oviedo, Asturias, España
| | - M Á Peinado Montes
- Servicio de Radiofísica y Protección Radiológica, Hospital Universitario Central de Asturias, Oviedo, Asturias, España
| | - M L Domínguez Grande
- Servicio de Medicina Nuclear, Hospital Universitario Central de Asturias, Oviedo, Asturias, España
| | - N Martín Fernández
- Servicio de Medicina Nuclear, Hospital Universitario Central de Asturias, Oviedo, Asturias, España
| | - A Gómez de Iturriaga Piña
- Departamento de Cirugía, Radiología y Medicina Física, UPV/EHU, Leioa, Bizkaia, España; Servicio de Oncología Radioterápica, Hospital Universitario Gurutzeta-Cruces/Instituto de Investigación Sanitaria BioCruces, Barakaldo, Bizkaia, España
| | - P Mínguez Gabiña
- Unidad de Protección Radiológica y Radiofísica, Hospital Universitario Gurutzeta-Cruces/Instituto de Investigación Sanitaria BioCruces, Barakaldo, Bizkaia, España
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Ramonaheng K, van Staden JA, du Raan H. The effect of calibration factors and recovery coefficients on 177Lu SPECT activity quantification accuracy: a Monte Carlo study. EJNMMI Phys 2021; 8:27. [PMID: 33738605 PMCID: PMC7973313 DOI: 10.1186/s40658-021-00365-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 02/08/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Different gamma camera calibration factor (CF) geometries have been proposed to convert SPECT data into units of activity concentration. However, no consensus has been reached on a standardised geometry. The CF is dependent on the selected geometry and is further affected by partial volume effects. This study investigated the effect of two CF geometries and their corresponding recovery coefficients (RCs) on the quantification accuracy of 177Lu SPECT images using Monte Carlo simulations. METHODS The CF geometries investigated were (i) a radioactive-sphere surrounded by non-radioactive water (sphere-CF) and (ii) a cylindrical phantom uniformly filled with radioactive water (cylinder-CF). Recovery coefficients were obtained using the sphere-CF and cylinder-CF, yielding the sphere-RC and cylinder-RC values, respectively, for partial volume correction (PVC). The quantification accuracy was evaluated using four different-sized spheres (15.6-65.4 ml) and a kidney model with known activity concentrations inside a cylindrical, torso and patient phantom. Images were reconstructed with the 3D OS-EM algorithm incorporating attenuation, scatter and detector-response corrections. Segmentation was performed using the physical size and a small cylindrical volume inside the cylinder for the sphere-CF and cylinder-CF, respectively. RESULTS The sphere quantification error (without PVC) was better for the sphere-CF (≤ - 5.54%) compared to the cylinder-CF (≤ - 20.90%), attributed to the similar geometry of the quantified and CF spheres. Partial volume correction yielded comparable results for the sphere-CF-RC (≤ 3.47%) and cylinder-CF-RC (≤ 3.53%). The accuracy of the kidney quantification was poorer (≤ 22.34%) for the sphere-CF without PVC compared to the cylinder-CF (≤ 2.44%). With PVC, the kidney quantification results improved and compared well for the sphere-CF-RC (≤ 3.50%) and the cylinder-CF-RC (≤ 3.45%). CONCLUSION The study demonstrated that upon careful selection of CF-RC combinations, comparable quantification errors (≤ 3.53%) were obtained between the sphere-CF-RC and cylinder-CF-RC, when all corrections were applied.
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Affiliation(s)
- Keamogetswe Ramonaheng
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa.
| | - Johannes A van Staden
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
| | - Hanlie du Raan
- Department of Medical Physics, Faculty of Health Sciences, University of the Free State, PO Box 339, Bloemfontein, 9300, South Africa
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15
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Lee JS. A Review of Deep-Learning-Based Approaches for Attenuation Correction in Positron Emission Tomography. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2021. [DOI: 10.1109/trpms.2020.3009269] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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16
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Santoro L, Pitalot L, Trauchessec D, Mora-Ramirez E, Kotzki PO, Bardiès M, Deshayes E. Clinical implementation of PLANET® Dose for dosimetric assessment after [ 177Lu]Lu-DOTA-TATE: comparison with Dosimetry Toolkit® and OLINDA/EXM® V1.0. EJNMMI Res 2021; 11:1. [PMID: 33394212 PMCID: PMC7782649 DOI: 10.1186/s13550-020-00737-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/23/2020] [Indexed: 01/03/2023] Open
Abstract
Background The aim of this study was to compare a commercial dosimetry workstation (PLANET® Dose) and the dosimetry approach (GE Dosimetry Toolkit® and OLINDA/EXM® V1.0) currently used in our department for quantification of the absorbed dose (AD) to organs at risk after peptide receptor radionuclide therapy with [177Lu]Lu-DOTA-TATE. Methods An evaluation on phantom was performed to determine the SPECT calibration factor variations over time and to compare the Time Integrated Activity Coefficients (TIACs) obtained with the two approaches. Then, dosimetry was carried out with the two tools in 21 patients with neuroendocrine tumours after the first and second injection of 7.2 ± 0.2 GBq of [177Lu]Lu-DOTA-TATE (40 dosimetry analyses with each software). SPECT/CT images were acquired at 4 h, 24 h, 72 h and 192 h post-injection and were reconstructed using the Xeleris software (General Electric). The liver, spleen and kidneys masses and TIACs were determined using Dosimetry Toolkit® (DTK) and PLANET® Dose. The ADs were calculated using OLINDA/EXM® V1.0 and the Local Deposition Method (LDM) or Dose voxel-Kernel convolution (DK) on PLANET® Dose. Results With the phantom, the 3D calibration factors showed a slight variation (0.8% and 3.3%) over time, and TIACs of 225.19 h and 217.52 h were obtained with DTK and PLANET® Dose, respectively. In patients, the root mean square deviation value was 8.9% for the organ masses, 8.1% for the TIACs, and 9.1% and 7.8% for the ADs calculated with LDM and DK, respectively. The Lin’s concordance correlation coefficient was 0.99 and the Bland–Altman plot analysis estimated that the AD value difference between methods ranged from − 0.75 to 0.49 Gy, from − 0.20 to 0.64 Gy, and from − 0.43 to 1.03 Gy for 95% of the 40 liver, kidneys and spleen dosimetry analyses. The dosimetry method had a minor influence on AD differences compared with the image registration and organ segmentation steps. Conclusions The ADs to organs at risk obtained with the new workstation PLANET® Dose are concordant with those calculated with the currently used software and in agreement with the literature. These results validate the use of PLANET® Dose in clinical routine for patient dosimetry after targeted radiotherapy with [177Lu]Lu-DOTA-TATE.
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Affiliation(s)
- Lore Santoro
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), Univ. Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex 5, France.
| | - L Pitalot
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), Univ. Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex 5, France
| | - D Trauchessec
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), Univ. Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex 5, France
| | - E Mora-Ramirez
- Centre de Recherche en Cancérologie de Toulouse, Toulouse, France.,INSERM, UMR 1037, Toulouse III Paul Sabatier University, Toulouse, France.,University of Costa Rica, Physics School, CICANUM, San José, Costa Rica
| | - P O Kotzki
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), Univ. Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex 5, France.,Montpellier Cancer Research Institute, UMR 1194, Univ. Montpellier, Montpellier, France
| | - M Bardiès
- Centre de Recherche en Cancérologie de Toulouse, Toulouse, France.,INSERM, UMR 1037, Toulouse III Paul Sabatier University, Toulouse, France
| | - E Deshayes
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), Univ. Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex 5, France.,Montpellier Cancer Research Institute, UMR 1194, Univ. Montpellier, Montpellier, France
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17
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Tomographic 99mTc radioactivity quantification in three-dimensional printed polymeric phantoms with bioinspired geometries. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2020.109130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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18
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Finocchiaro D, Gear JI, Fioroni F, Flux GD, Murray I, Castellani G, Versari A, Iori M, Grassi E. Uncertainty analysis of tumour absorbed dose calculations in molecular radiotherapy. EJNMMI Phys 2020; 7:63. [PMID: 33044651 PMCID: PMC7550507 DOI: 10.1186/s40658-020-00328-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 09/16/2020] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Internal dosimetry evaluation consists of a multi-step process ranging from imaging acquisition to absorbed dose calculations. Assessment of uncertainty is complicated and, for that reason, it is commonly ignored in clinical routine. However, it is essential for adequate interpretation of the results. Recently, the EANM published a practical guidance on uncertainty analysis for molecular radiotherapy based on the application of the law of propagation of uncertainty. In this study, we investigated the overall uncertainty on a sample of a patient following the EANM guidelines. The aim of this study was to provide an indication of the typical uncertainties that may be expected from performing dosimetry, to determine parameters that have the greatest effect on the accuracy of calculations and to consider the potential improvements that could be made if these effects were reduced. RESULTS Absorbed doses and the relative uncertainties were calculated for a sample of 49 patients and a total of 154 tumours. A wide range of relative absorbed dose uncertainty values was observed (14-102%). Uncertainties associated with each quantity along the absorbed dose calculation chain (i.e. volume, recovery coefficient, calibration factor, activity, time-activity curve fitting, time-integrated activity and absorbed dose) were estimated. An equation was derived to describe the relationship between the uncertainty in the absorbed dose and the volume. The largest source of error was the VOI delineation. By postulating different values of FWHM, the impact of the imaging system spatial resolution on the uncertainties was investigated. DISCUSSION To the best of our knowledge, this is the first analysis of uncertainty in molecular radiotherapy based on a cohort of clinical cases. Wide inter-lesion variability of absorbed dose uncertainty was observed. Hence, a proper assessment of the uncertainties associated with the calculations should be considered as a basic scientific standard. A model for a quick estimate of uncertainty without implementing the entire error propagation schema, which may be useful in clinical practice, was presented. Ameliorating spatial resolution may be in future the key factor for accurate absorbed dose assessment.
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Affiliation(s)
- Domenico Finocchiaro
- Medical Physics Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy.,Department of Physics and Astronomy, University of Bologna, Bologna, Italy
| | - Jonathan I Gear
- The Royal Marsden NHS Foundation Trust & Institute of Cancer Research, Downs Road, Sutton, SM2 5PT, UK
| | - Federica Fioroni
- Medical Physics Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy.
| | - Glenn D Flux
- The Royal Marsden NHS Foundation Trust & Institute of Cancer Research, Downs Road, Sutton, SM2 5PT, UK
| | - Iain Murray
- The Royal Marsden NHS Foundation Trust & Institute of Cancer Research, Downs Road, Sutton, SM2 5PT, UK
| | - Gastone Castellani
- Department of Physics and Astronomy, University of Bologna, Bologna, Italy
| | - Annibale Versari
- Nuclear Medicine Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy
| | - Mauro Iori
- Medical Physics Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy
| | - Elisa Grassi
- Medical Physics Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy
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19
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Huizing DMV, Sinaasappel M, Dekker MC, Stokkel MPM, de Wit – van der Veen BJ. 177
Lutetium SPECT/CT: Evaluation of collimator, photopeak and scatter correction. J Appl Clin Med Phys 2020; 21:272-277. [PMID: 32790140 PMCID: PMC7497918 DOI: 10.1002/acm2.12991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 06/26/2020] [Accepted: 07/09/2020] [Indexed: 11/10/2022] Open
Abstract
Purpose The goal of this study was to find the optimal combination of collimator, photopeak and scatter correction for 177Lutetium (177Lu) SPECT/CT imaging. Methods Three experiments [sphere‐to‐background ratios (SBR) 50:1, 10:1, and 2:1] were performed with the NEMA Image Quality phantom filled with 177Lu‐trichloride. SPECT/CT acquisitions were performed with the medium‐energy low‐penetration (MELP) collimator and 99mTc/Krypton collimator. For each acquisition six reconstructions, all with attenuation correction (AC), were made: the 113‐keV photopeak only, the 208‐keV photopeak only and both photopeaks combined, each with or without scatter correction (SC). Image quality was assessed using contrast‐to‐noise ratios (CNR), quantification accuracy by means of recovery coefficients (RCs) and the spatial resolution using line profiles. Results With SBR 50:1 and 10:1, both collimators met the Rose criterion (CNR > 5), whereas the MELP collimator showed a higher CNR for the 2:1 ratio. The RCmean was higher with the MELP collimator, most explicit after the 208‐keV AC/SC reconstruction for all acquisitions. The line profiles showed a better spatial resolution for the MELP collimator and the 208‐keV AC/SC reconstructions. Conclusion 177Lu SPECT/CT image quality and quantification was most optimal when acquired with the MELP collimator and reconstructed using the 208‐keV photopeak, with AC and SC.
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Affiliation(s)
- Daphne M. V. Huizing
- Department of Nuclear Medicine Netherlands Cancer Institute Amsterdam The Netherlands
| | - Michiel Sinaasappel
- Department of Physics Netherlands Cancer Institute Amsterdam The Netherlands
| | - Marien C. Dekker
- Department of Nuclear Medicine Netherlands Cancer Institute Amsterdam The Netherlands
| | - Marcel P. M. Stokkel
- Department of Nuclear Medicine Netherlands Cancer Institute Amsterdam The Netherlands
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20
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Comparison of different calculation techniques for absorbed dose assessment in patient specific peptide receptor radionuclide therapy. PLoS One 2020; 15:e0236466. [PMID: 32764764 PMCID: PMC7413508 DOI: 10.1371/journal.pone.0236466] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 07/06/2020] [Indexed: 11/19/2022] Open
Abstract
Aim The present work concerns the comparison of the performances of three systems for dosimetry in RPT that use different techniques for absorbed dose calculation (organ-level dosimetry, voxel-level dose kernel convolution and Monte Carlo simulations). The aim was to assess the importance of the choice of the most adequate calculation modality, providing recommendations about the choice of the computation tool. Methods The performances were evaluated both on phantoms and patients in a multi-level approach. Different phantoms filled with a 177Lu-radioactive solution were used: a homogeneous cylindrical phantom, a phantom with organ-shaped inserts and two cylindrical phantoms with inserts different for shape and volume. A total of 70 patients with NETs treated by PRRT with 177Lu-DOTATOC were retrospectively analysed. Results The comparisons were performed mainly between the mean values of the absorbed dose in the regions of interest. A general better agreement was obtained between Dose kernel convolution and Monte Carlo simulations results rather than between either of these two and organ-level dosimetry, both for phantoms and patients. Phantoms measurements also showed the discrepancies mainly depend on the geometry of the inserts (e.g. shape and volume). For patients, differences were more pronounced than phantoms and higher inter/intra patient variability was observed. Conclusion This study suggests that voxel-level techniques for dosimetry calculation are potentially more accurate and personalized than organ-level methods. In particular, a voxel-convolution method provides good results in a short time of calculation, while Monte Carlo based computation should be conducted with very fast calculation systems for a possible use in clinics, despite its intrinsic higher accuracy. Attention to the calculation modality is recommended in case of clinical regions of interest with irregular shape and far from spherical geometry, in which Monte Carlo seems to be more accurate than voxel-convolution methods.
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Mora-Ramirez E, Santoro L, Cassol E, Ocampo-Ramos JC, Clayton N, Kayal G, Chouaf S, Trauchessec D, Pouget JP, Kotzki PO, Deshayes E, Bardiès M. Comparison of commercial dosimetric software platforms in patients treated with 177 Lu-DOTATATE for peptide receptor radionuclide therapy. Med Phys 2020; 47:4602-4615. [PMID: 32632928 PMCID: PMC7589428 DOI: 10.1002/mp.14375] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 12/17/2022] Open
Abstract
Purpose The aim of this study was to quantitatively compare five commercial dosimetric software platforms based on the analysis of clinical datasets of patients who benefited from peptide receptor radionuclide therapy (PRRT) with 177Lu‐DOTATATE (LUTATHERA®). Methods The dosimetric analysis was performed on two patients during two cycles of PRRT with 177Lu. Single photon emission computed tomography/computed tomography images were acquired at 4, 24, 72, and 192 h post injection. Reconstructed images were generated using Dosimetry Toolkit® (DTK) from Xeleris™ and HybridRecon‐Oncology version_1.3_Dicom (HROD) from HERMES. Reconstructed images using DTK were analyzed using the same software to calculate time‐integrated activity coefficients (TIAC), and mean absorbed doses were estimated using OLINDA/EXM V1.0 with mass correction. Reconstructed images from HROD were uploaded into PLANET® OncoDose from DOSIsoft, STRATOS from Phillips, Hybrid Dosimetry Module™ from HERMES, and SurePlan™ MRT from MIM. Organ masses, TIACs, and mean absorbed doses were calculated from each application using their recommendations. Results The majority of organ mass estimates varied by <9.5% between all platforms. The highest variability for TIAC results between platforms was seen for the kidneys (28.2%) for the two patients and the two treatment cycles. Relative standard deviations in mean absorbed doses were slightly higher compared with those observed for TIAC, but remained of the same order of magnitude between all platforms. Conclusions When applying a similar processing approach, results obtained were of the same order of magnitude regardless of the platforms used. However, the comparison of the performances of currently available platforms is still difficult as they do not all address the same parts of the dosimetric analysis workflow. In addition, the way in which data are handled in each part of the chain from data acquisition to absorbed doses may be different, which complicates the comparison exercise. Therefore, the dissemination of commercial solutions for absorbed dose calculation calls for the development of tools and standards allowing for the comparison of the performances between dosimetric software platforms.
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Affiliation(s)
- Erick Mora-Ramirez
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France.,Escuela de Física - CICANUM, Universidad de Costa Rica, San José, 11501-2060, Costa Rica
| | - Lore Santoro
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier, Montpellier, F-34298, France
| | - Emmanuelle Cassol
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France.,Département de Médecine Nucléaire, Hôpitaux Toulouse, Toulouse, F-31059, France.,Faculté de Médecine Rangueil, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France
| | - Juan C Ocampo-Ramos
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France
| | - Naomi Clayton
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France
| | - Gunjan Kayal
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France.,SCK CEN, Belgian Nuclear Research Centre, Boeretang 200, Mol, BE-2400, Belgium
| | - Soufiane Chouaf
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier, Montpellier, F-34298, France
| | - Dorian Trauchessec
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier, Montpellier, F-34298, France
| | - Jean-Pierre Pouget
- Institut de Recherche en Cancérologie de Montpellier (IRCM), Inserm U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, F-34298, France
| | - Pierre-Olivier Kotzki
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier, Montpellier, F-34298, France.,Institut de Recherche en Cancérologie de Montpellier (IRCM), Inserm U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, F-34298, France
| | - Emmanuel Deshayes
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier, Montpellier, F-34298, France.,Institut de Recherche en Cancérologie de Montpellier (IRCM), Inserm U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, F-34298, France
| | - Manuel Bardiès
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, Toulouse, F-31037, France.,INSERM, UMR 1037, Université Toulouse III Paul Sabatier, Toulouse, F-31062, France
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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: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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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Abstract
The continuous development of SPECT over the past 50 years has led to improved image quality and increased diagnostic confidence. The most influential developments include the realization of hybrid SPECT/CT devices, as well as the implementation of attenuation correction and iterative image reconstruction techniques. These developments have led to a preference for SPECT/CT devices over SPECT-only systems and to the widespread adoption of the former, strengthening the role of SPECT/CT as the workhorse of Nuclear Medicine imaging. New trends in the ongoing development of SPECT/CT are diverse. For example, whole-body SPECT/CT images, consisting of acquisitions from multiple consecutive bed positions in the manner of PET/CT, are increasingly performed. Additionally, in recent years, some interesting approaches in detector technology have found their way into commercial products. For example, some SPECT cameras dedicated to specific organs employ semiconductor detectors made of cadmium telluride or cadmium zinc telluride, which have been shown to increase the obtainable image quality by offering a higher sensitivity and energy resolution. However, the advent of quantitative SPECT/CT which, like PET, can quantify the amount of tracer in terms of Bq/mL or as a standardized uptake value could be regarded as most important development. It is a major innovation that will lead to increased diagnostic accuracy and confidence, especially in longitudinal studies and in the monitoring of treatment response. The current work comprises two main aspects. At first, physical and technical fundamentals of SPECT image formation are described and necessary prerequisites of quantitative SPECT/CT are reviewed. Additionally, the typically achievable quantitative accuracy based on reports from the literature is given. Second, an extensive list of studies reporting on clinical applications of quantitative SPECT/CT is provided and reviewed.
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Affiliation(s)
- Philipp Ritt
- Clinic of Nuclear Medicine, University Hospital Erlangen, Ulmenweg 18, 91054, Erlangen, Germany.
| | - Torsten Kuwert
- Clinic of Nuclear Medicine, University Hospital Erlangen, Ulmenweg 18, 91054, Erlangen, Germany
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24
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Rinscheid A, Kletting P, Eiber M, Beer AJ, Glatting G. Technical Note: Optimal sampling schedules for kidney dosimetry based on the hybrid planar/SPECT method in 177 Lu-PSMA therapy. Med Phys 2019; 46:5861-5866. [PMID: 31587333 DOI: 10.1002/mp.13846] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/27/2019] [Accepted: 09/19/2019] [Indexed: 11/11/2022] Open
Abstract
PURPOSE Accurate and precise renal dosimetry during 177 Lu-labeled prostate-specific membrane antigen (PSMA) radioligand therapy is crucial for therapy decisions. Sampling schedules for estimating the necessary time-integrated activity coefficients (TIACs) are not optimized and standardized for clinical practice. Therefore, a simulation study to determine optimal sampling schedules (OSSs) was performed on 13 virtual 177 Lu-PSMA I&T therapy patients. METHOD A total of 880 clinically feasible sampling schedules for planar imaging (three time points) were investigated. To simulate the hybrid planar/SPECT method, an additional quantitative SPECT/CT measurement following one planar image was considered. For each sampling schedule and patient, the activity values were generated separately. Measurement noise was modeled by drawing random numbers of log-normal distributions. The used fractional standard deviations (FSD) differed depending on the imaging modality. For activity values assigned to planar imaging, systematic noise between 25% and 75% of the total noise was simulated. After fitting with a mono-exponential function, the root-mean-squared errors of the deviations of the simulated TIACs from the ground truth for 1000 replications were used to determine the OSS. The uncertainties of the TIACs and renal dose coefficients were estimated. RESULTS For the hybrid planar/SPECT method, OSSs were determined to be (3-4, 72-76, 124-144) h post injection (p.i.) with the quantitative SPECT/CT scan shortly after the second measurement. The accuracy and precision of the determined TIACs were in the range of (-3.0 ± 6.2)% and (-1.0 ± 6.5)%. This precision was improved by a factor 2-3 compared to dosimetry based on planar images only. Similar results were obtained for the renal dose coefficients. The virtual patients' renal dose coefficients were (0.68 ± 0.24) Gy/GBq indicating that a population-based method yields an uncertainty of 35%. CONCLUSIONS Dosimetry based on the hybrid planar/SPECT method with OSS outperforms dosimetry based on planar images. The high variability in dose coefficients between the virtual patients demonstrates the need for individualized dosimetry.
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Affiliation(s)
- Andreas Rinscheid
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany.,Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany
| | - Peter Kletting
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany.,Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany
| | - Matthias Eiber
- Department of Nuclear Medicine, Klinikum Rechts der Isar, Technische Universität München, 81675, München, Germany
| | - Ambros J Beer
- Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany
| | - Gerhard Glatting
- Medical Radiation Physics, Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany.,Department of Nuclear Medicine, Ulm University, 89081, Ulm, Germany
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Texture analysis in 177Lu SPECT phantom images: Statistical assessment of uniformity requirements using texture features. PLoS One 2019; 14:e0218814. [PMID: 31365526 PMCID: PMC6668785 DOI: 10.1371/journal.pone.0218814] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 06/10/2019] [Indexed: 01/04/2023] Open
Abstract
The purpose of this study was to apply texture analysis (TA) to evaluate the uniformity of SPECT images reconstructed with the 3D Ordered Subsets Expectation Maximization (3D-OSEM) algorithm. For this purpose, a cylindrical homogeneous phantom filled with 177Lu was used and a total of 24 spherical volumes of interest (VOIs) were considered inside the phantom. The location of the VOIs was chosen in order to define two different configurations, i.e. gravity and radial configuration. The former configuration was used to investigate the uniformity of distribution of 177Lu inside the phantom, while the latter configuration was used to investigate the lack of uniformity from center towards edge of the images. For each VOI, the trend of different texture features considered as a function of 3D-OSEM updates was investigated in order to evaluate the influence of reconstruction parameters. TA was performed using CGITA software. The equality of the average texture feature trends in both spatial configurations was assumed as the null hypothesis and was tested by functional analysis of variance (fANOVA). With regard to the gravity configuration, no texture feature rejected the null hypothesis when the number of subsets increased. For the radial configuration, the statistical analysis revealed that, depending on the 3D-OSEM parameters used, a few texture features were capable of detecting the non-uniformity of 177Lu distribution inside the phantom moving from the center of the image towards its edge. Finally, cross-correlation coefficients were calculated to better identify the features that could play an important role in assessing quality assurance procedures performed on SPECT systems.
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Timmermand OV, Elgqvist J, Beattie KA, Örbom A, Larsson E, Eriksson SE, Thorek DL, Beattie BJ, Tran TA, Ulmert D, Strand SE. Preclinical efficacy of hK2 targeted [ 177Lu]hu11B6 for prostate cancer theranostics. Theranostics 2019; 9:2129-2142. [PMID: 31149033 PMCID: PMC6531309 DOI: 10.7150/thno.31179] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/17/2019] [Indexed: 12/12/2022] Open
Abstract
Androgen ablating drugs increase life expectancy in men with metastatic prostate cancer, but resistance inevitably develops. In a majority of these recurrent tumors, the androgen axis is reactivated in the form of increased androgen receptor (AR) expression. Targeting proteins that are expressed as a down-stream effect of AR activity is a promising rationale for management of this disease. The humanized IgG1 antibody hu11B6 internalizes into prostate and prostate cancer (PCa) cells by binding to the catalytic cleft of human kallikrein 2 (hK2), a prostate specific enzyme governed by the AR-pathway. In a previous study, hu11B6 conjugated with Actinium-225 (225Ac), a high linear energy transfer (LET) radionuclide, was shown to generate an AR-upregulation driven feed-forward mechanism that is believed to enhance therapeutic efficacy. We assessed the efficacy of hu11B6 labeled with a low LET beta-emitter, Lutetium-177 (177Lu) and investigated whether similar tumor killing and AR-enhancement is produced. Moreover, single-photon emission computed tomography (SPECT) imaging of 177Lu is quantitatively accurate and can be used to perform treatment planning. [177Lu]hu11B6 therefore has significant potential as a theranostic agent. Materials and Methods: Subcutaneous PCa xenografts (LNCaP s.c.) were grown in male mice. Biokinetics at 4-336 h post injection and uptake as a function of the amount of hu11B6 injected at 72 h were studied. Over a 30 to 120-day treatment period the therapeutic efficacy of different activities of [177Lu]hu11B6 were assessed by volumetric tumor measurements, blood cell counts, molecular analysis of the tumor as well as SPECT/CT imaging. Organ specific mean absorbed doses were calculated, using a MIRD-scheme, based on biokinetic data and rodent specific S-factors from a modified MOBY phantom. Tumor tissues of treated xenografts were immunohistochemically (IHC) stained for Ki-67 (proliferation) and AR, SA-β-gal activity (senescence) and analyzed by digital autoradiography (DAR). Results: Organ-to-blood and tumor-to-blood ratios were independent of hu11B6 specific activity except for the highest amount of antibody (150 µg). Tumor accumulation of [177Lu]hu11B6 peaked at 168 h with a specific uptake of 29 ± 9.1 percent injected activity per gram (%IA/g) and low accumulation in normal organs except in the submandibular gland (15 ± 4.5 %IA/g), attributed to a cross-reaction with mice kallikreins in this organ, was seen. However, SPECT imaging with therapeutic amounts of [177Lu]hu11B6 revealed no peak in tumor accumulation at 7 d, probably due to cellular retention of 177Lu and decreasing tumor volumes. For [177Lu]hu11B6 treated mice, tumor decrements of up to 4/5 of the initial tumor volume and reversible myelotoxicity with a nadir at 12 d were observed after a single injection. Tumor volume reduction correlated with injected activity and the absorbed dose. IHC revealed retained expression of AR throughout treatment and that Ki-67 staining reached a nadir at 9-14 d which coincided with high SA- β-gal activity (14 d). Quantification of nuclei staining showed that Ki-67 expression correlated negatively with activity uptake. AR expression levels in cells surviving therapy compared to previous timepoints and to controls at 30 d were significantly increased (p = 0.017). Conclusions: This study shows that hu11B6 labeled with the low LET beta-emitting radionuclide 177Lu can deliver therapeutic absorbed doses to prostate cancer xenografts with transient hematological side-effects. The tumor response correlated with the absorbed dose both on a macro and a small scale dosimetric level. Analysis of AR staining showed that AR protein levels increased late in the study suggesting a therapeutic mechanism, a feed forward mechanism coupled to AR driven response to DNA damage or clonal lineage selection, similar to that reported in high LET alpha-particle therapy using 225Ac labeled hu11B6, however emerging at a later timepoint.
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27
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Finocchiaro D, Berenato S, Grassi E, Bertolini V, Castellani G, Lanconelli N, Versari A, Spezi E, Iori M, Fioroni F. Partial volume effect of SPECT images in PRRT with 177Lu labelled somatostatin analogues: A practical solution. Phys Med 2019; 57:153-159. [PMID: 30738519 DOI: 10.1016/j.ejmp.2018.12.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/26/2018] [Accepted: 12/20/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND At present activity quantification is one of the most critical step in dosimetry calculation, and Partial Volume Effect (PVE) one of the most important source of error. In recent years models based upon phantoms that incorporate hot spheres have been used to establish recovery models. In this context the goal of this study was to point out the most critical issues related to PVE and to establish a model closer to a biological imaging environment. METHODS Two different phantoms, filled with a 177Lu solution, were used to obtain the PVE Recovery Coefficients (RCs): a phantom with spherical inserts and a phantom with organ-shaped inserts. Two additional phantoms with inserts of various geometrical shapes and an anthropomorphic phantom were acquired to compare the real activities to predicted values after PVE correction. RESULTS The RCs versus volume of the inserts produced two different curves, one for the spheres and one for the organs. After PVE correction, accuracy on activity quantification averaged over all inserts of three test phantoms passed from -26% to 1.3% (from 26% to 10% for absolute values). CONCLUSION RCs is a simple method for PVE correction easily applicable in clinical routine. The use of two different models for organs and lesions has permitted to closely mimic the situation in a living subject. A marked improvement in the quantification of activity was observed when PVE correction was adopted, even if further investigations should be performed for more accurate models of PVE corrections.
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Affiliation(s)
- Domenico Finocchiaro
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy; Department of Physics, University of Bologna, Italy
| | | | - Elisa Grassi
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy.
| | - Valentina Bertolini
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy
| | | | | | - Annibale Versari
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Nuclear Medicine Unit, Reggio Emilia, Italy
| | - Emiliano Spezi
- School of Engineering, Cardiff University, Cardiff, UK; Department of Medical Physics, Velindre Cancer Centre, Cardiff, UK
| | - Mauro Iori
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy
| | - Federica Fioroni
- Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy
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Karimi Ghodoosi E, D'Alessandria C, Li Y, Bartel A, Köhner M, Höllriegl V, Navab N, Eiber M, Li WB, Frey E, Ziegler S. The effect of attenuation map, scatter energy window width, and volume of interest on the calibration factor calculation in quantitative 177Lu SPECT imaging: Simulation and phantom study. Phys Med 2018; 56:74-80. [DOI: 10.1016/j.ejmp.2018.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 11/07/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022] Open
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Santoro L, Mora-Ramirez E, Trauchessec D, Chouaf S, Eustache P, Pouget JP, Kotzki PO, Bardiès M, Deshayes E. Implementation of patient dosimetry in the clinical practice after targeted radiotherapy using [ 177Lu-[DOTA0, Tyr3]-octreotate. EJNMMI Res 2018; 8:103. [PMID: 30498938 PMCID: PMC6265360 DOI: 10.1186/s13550-018-0459-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/20/2018] [Indexed: 01/01/2023] Open
Abstract
Background This study’s aim was to develop our dosimetric methodology using a commercial workstation for the routine evaluation of the organs at risk during peptide receptor radionuclide therapy (PRRT) with 177Lu. Methods First, planar and SPECT sensitivity factors were determined on phantoms. The reconstruction parameters were optimized by SPECT/CT image acquisition using a NEMA IEC phantom containing a 500 ml bottle of 177Lu, to simulate a kidney. The recovery coefficients were determined on various phantoms. For the red marrow, this was calculated using a NEMA IEC phantom that contained a centrally placed bottle of 80 ml of 177Lu (to model the L2-L4 red marrow) flanked by two 200 ml bottles with 177Lu to simulate the kidneys. Then, SPECT/CT images were acquired at 4, 24, 72, and 192 h after injection in 12 patients with neuroendocrine tumors who underwent PRRT with 177Lu-DOTATATE. SPECT data were reconstructed using the iterative ordered subset expectation maximization (OSEM) method, with six iterations and ten subsets, attenuation, scatter, recovery resolution corrections, and a Gaussian post-filter of 0.11 cm. The liver, spleen, kidneys, and red marrow dose per administered activity (AD/A admin) values were calculated with the Medical Internal Radiation Dose (MIRD) formalism and the residence times (Dosimetry toolkit® application) using standard and CT imaging-based organ masses (OLINDA/EXM® V1.0 software). Results Sensitivity factors of 6.11 ± 0.01 and 5.67 ± 0.08 counts/s/MBq were obtained with planar and SPECT/CT acquisitions, respectively. A recovery coefficient of 0.78 was obtained for the modeled L2–L4 red marrow. The mean AD/A admin values were 0.43 ± 0.13 mGy/MBq [0.27–0.91] for kidneys, 0.54 ± 0.58 mGy/MBq [0.12–2.26] for liver, 0.61 ± 0.13 mGy/MBq [0.42–0.89] for spleen, and 0.04 ± 0.02 mGy/MBq [0.01–0.09] for red marrow. The AD/A admin values varied when calculated using the personalized and standard organ mass, particularly for kidneys (p = 1 × 10−7), spleen (p = 0.0069), and red marrow (p = 0.0027). Intra-patient differences were observed especially in organs close to or including tumor cells or metastases. Conclusions The obtained AD/A admin values were in agreement with the literature data. This study shows the technical feasibility of patient dosimetry in clinical practice and the need to obtain patient-specific information.
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Affiliation(s)
- Lore Santoro
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France.
| | - Erick Mora-Ramirez
- Centre de Recherche en Cancérologie de Toulouse, Toulouse, France.,INSERM, UMR 1037, Toulouse III Paul Sabatier University, Toulouse, France.,University of Costa Rica, Physics School, CICANUM, San Jose, Costa Rica
| | - Dorian Trauchessec
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France
| | - Soufiane Chouaf
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France
| | - Pierre Eustache
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France
| | - Jean-Pierre Pouget
- Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, France
| | - Pierre-Olivier Kotzki
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France.,Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, France
| | - Manuel Bardiès
- Centre de Recherche en Cancérologie de Toulouse, Toulouse, France.,INSERM, UMR 1037, Toulouse III Paul Sabatier University, Toulouse, France
| | - Emmanuel Deshayes
- Nuclear Medicine Department, Montpellier Cancer Institute (ICM), University of Montpellier, 208 Avenue des Apothicaires, 34298, Montpellier Cedex5, France.,Institut de Recherche en Cancérologie de Montpellier (IRCM), INSERM U1194, Université de Montpellier, Institut Régional du Cancer de Montpellier (ICM), Montpellier, France
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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: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [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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Bavelaar BM, Lee BQ, Gill MR, Falzone N, Vallis KA. Subcellular Targeting of Theranostic Radionuclides. Front Pharmacol 2018; 9:996. [PMID: 30233374 PMCID: PMC6131480 DOI: 10.3389/fphar.2018.00996] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/13/2018] [Indexed: 12/16/2022] Open
Abstract
The last decade has seen rapid growth in the use of theranostic radionuclides for the treatment and imaging of a wide range of cancers. Radionuclide therapy and imaging rely on a radiolabeled vector to specifically target cancer cells. Radionuclides that emit β particles have thus far dominated the field of targeted radionuclide therapy (TRT), mainly because the longer range (μm-mm track length) of these particles offsets the heterogeneous expression of the molecular target. Shorter range (nm-μm track length) α- and Auger electron (AE)-emitting radionuclides on the other hand provide high ionization densities at the site of decay which could overcome much of the toxicity associated with β-emitters. Given that there is a growing body of evidence that other sensitive sites besides the DNA, such as the cell membrane and mitochondria, could be critical targets in TRT, improved techniques in detecting the subcellular distribution of these radionuclides are necessary, especially since many β-emitting radionuclides also emit AE. The successful development of TRT agents capable of homing to targets with subcellular precision demands the parallel development of quantitative assays for evaluation of spatial distribution of radionuclides in the nm-μm range. In this review, the status of research directed at subcellular targeting of radionuclide theranostics and the methods for imaging and quantification of radionuclide localization at the nanoscale are described.
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Affiliation(s)
| | | | | | | | - Katherine A. Vallis
- CR-UK/MRC Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, United Kingdom
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32
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Huizing DMV, de Wit-van der Veen BJ, Verheij M, Stokkel MPM. Dosimetry methods and clinical applications in peptide receptor radionuclide therapy for neuroendocrine tumours: a literature review. EJNMMI Res 2018; 8:89. [PMID: 30159614 PMCID: PMC6115319 DOI: 10.1186/s13550-018-0443-z] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/21/2018] [Indexed: 12/25/2022] Open
Abstract
Background The main challenge for systemic radiation therapy using radiopharmaceuticals (SRT) is to optimise the dose delivered to the tumour, while minimising normal tissue irradiation. Dosimetry could help to increase therapy response and decrease toxicity after SRT by individual treatment planning. Peptide receptor radionuclide therapy (PRRT) is an accepted SRT treatment option for irresectable and metastatic neuroendocrine tumours (NET). However, dosimetry in PRRT is not routinely performed, mainly due to the lack of evidence in literature and clinical implementation difficulties. The goal of this review is to provide insight in dosimetry methods and requirements and to present an overview of clinical aspects of dosimetry in PRRT for NET. Methods A PubMed query including the search criteria dosimetry, radiation dose, peptide receptor radionuclide therapy, and radionuclide therapy was performed. Articles were selected based on title and abstract, and description of dosimetric approach. Results A total of 288 original articles were included. The most important dosimetry methods, their main advantages and limitations, and implications in the clinical setting are discussed. An overview of dosimetry in clinical studies regarding PRRT treatment for NET is provided. Conclusion Clinical dosimetry in PRRT is feasible and can result in improved treatment outcomes. Current clinical dosimetry studies focus on safety and apply non-voxel-based dosimetry methods. Personalised treatment using sophisticated dosimetry methods to assess tumour and normal tissue uptake in clinical trials is the next step towards routine dosimetry in PRRT for NET. Electronic supplementary material The online version of this article (10.1186/s13550-018-0443-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daphne Merel Valerie Huizing
- Department of Nuclear Medicine, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | | | - Marcel Verheij
- Department of Radiation Oncology, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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33
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Lassmann M, Eberlein U. The Relevance of Dosimetry in Precision Medicine. J Nucl Med 2018; 59:1494-1499. [PMID: 30002109 DOI: 10.2967/jnumed.117.206649] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/29/2018] [Indexed: 11/16/2022] Open
Abstract
The aim of this review is to provide an overview of the most recent technologic developments in state-of-the-art equipment and tools for dosimetry in radionuclide therapies. This includes, but is not restricted to, calibration methods for imaging systems. In addition, a summary of new developments that consider the influence of small-scale dosimetry and of biologic effects on radionuclide therapies is given. Finally, the current limitations of patient-specific dosimetry such as bone-marrow dosimetry or dosimetry of α-emitters are discussed.
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Affiliation(s)
- Michael Lassmann
- Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Würzburg, Würzburg, Germany
| | - Uta Eberlein
- Klinik und Poliklinik für Nuklearmedizin, Universitätsklinikum Würzburg, Würzburg, Germany
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34
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Tran-Gia J, Lassmann M. Characterization of Noise and Resolution for Quantitative 177Lu SPECT/CT with xSPECT Quant. J Nucl Med 2018; 60:50-59. [DOI: 10.2967/jnumed.118.211094] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/14/2018] [Indexed: 12/29/2022] Open
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Tinaz S, Chow C, Kuo PH, Krupinski EA, Blumenfeld H, Louis ED, Zubal G. Semiquantitative Analysis of Dopamine Transporter Scans in Patients With Parkinson Disease. Clin Nucl Med 2018; 43:e1-e7. [PMID: 29112012 DOI: 10.1097/rlu.0000000000001885] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Dopamine transporter (DaT) imaging is an adjunct diagnostic tool in parkinsonian disorders. Interpretation of DaT scans is based on visual reads. SBRquant is an automated method that measures the striatal binding ratio (SBR) in DaT scans, but has yet to be optimized. We aimed to (1) optimize SBRquant parameters to distinguish between patients with Parkinson disease (PD) and healthy controls using the Parkinson's Progression Markers Initiative (PPMI) database and (2) test the validity of these parameters in an outpatient cohort. METHODS For optimization, 336 DaT scans (215 PD patients and 121 healthy controls) from the PPMI database were used. Striatal binding ratio was calculated varying the number of summed transverse slices (N) and positions of the striatal regions of interest (d). The resulting SBRs were evaluated using area under the receiver operating characteristic curve. The optimized parameters were then applied to 77 test patients (35 PD and 42 non-PD patients). Striatal binding ratios were also correlated with clinical measures in the PPMI-PD group. RESULTS The optimal parameters discriminated the training groups in the PPMI cohort with 95.8% sensitivity and 98.3% specificity (lowest putamen SBR threshold, 1.037). The same parameters discriminated the groups in the test cohort with 97.1% sensitivity and 100% specificity (lowest putamen SBR threshold, 0.875). A significant negative correlation (r = -0.24, P = 0.0004) was found between putamen SBRs and motor severity in the PPMI-PD group. CONCLUSIONS SBRquant discriminates DaT scans with high sensitivity and specificity. It has a high potential for use as a quantitative diagnostic aid in clinical and research settings.
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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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Deadtime effects in quantification of 177Lu activity for radionuclide therapy. EJNMMI Phys 2018; 5:2. [PMID: 29322344 PMCID: PMC5762619 DOI: 10.1186/s40658-017-0202-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 12/07/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate the deadtime (DT) effects that are present in 177Lu images acquired after radionuclide therapy injection, assess differences in DT based on the full spectrum and the photopeak-only measurements, and design a method to correct for the deadtime losses. A Siemens SymbiaT SPECT/CT camera with a medium energy collimator was used. A 295-mL bottle was placed off-center inside a large cylinder filled with water, and 177Lu activity was sequentially added up to a maximum of 9.12 GBq. The true count rates vs. observed count rates were plotted and fitted to the DT paralyzable model. This analysis was performed using counts recorded in the full spectrum and in other energy windows. The DT correction factors were calculated using the percentage difference between the true and the observed count rates. RESULTS The DT values of 5.99 ± 0.02 μs, 4.60 ± 0.052 μs, and 0.19 ± 0.18 μs were obtained for the primary photons (PP) recorded in the 113- and 208-keV photopeaks and for the full spectrum, respectively. For the investigated range of count rates, the DT correction factors of up to 23% were observed for PP corresponding to the 113-keV photopeak, while for the 208-keV photopeak values of up to 20% were obtained. These values were almost three times higher than the deadtime correction factors derived from the full spectrum. CONCLUSIONS The paralyzable model showed to be appropriate for the investigated range of counts, which were five to six times higher than those observed in the patient post-therapy imaging. Our results suggest that the deadtime corrections should be based on count losses in the scatter-corrected photopeak window and not on the deadtime determined from the full spectrum. Finally, a general procedure that can be followed to correct patient images for deadtime is presented.
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Grassi E, Fioroni F, Berenato S, Patterson N, Ferri V, Braglia L, Filice A, Versari A, Iori M, Spezi E. Effect of image registration on 3D absorbed dose calculations in 177 Lu-DOTATOC peptide receptor radionuclide therapy. Phys Med 2018; 45:177-185. [DOI: 10.1016/j.ejmp.2017.11.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 10/18/2017] [Accepted: 11/26/2017] [Indexed: 11/29/2022] Open
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Mezzenga E, D’Errico V, D’Arienzo M, Strigari L, Panagiota K, Matteucci F, Severi S, Paganelli G, Fenwick A, Bianchini D, Marcocci F, Sarnelli A. Quantitative accuracy of 177Lu SPECT imaging for molecular radiotherapy. PLoS One 2017; 12:e0182888. [PMID: 28806773 PMCID: PMC5564164 DOI: 10.1371/journal.pone.0182888] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 07/26/2017] [Indexed: 11/18/2022] Open
Abstract
The purpose of this study is to investigate the optimal reference geometry for gamma camera calibration. Yet another question of interest was to assess the influence of the number of 3D Ordered Subsets Expectation Maximization (3D-OSEM) updates on activity quantification for SPECT imaging with 177Lu. The accuracy of 177Lu activity quantification was assessed both in small and in large objects. Two different reference geometries, namely a cylindrical homogeneous phantom and a Jaszczak 16 ml sphere surrounded by cold water, were used to determine the gamma camera calibration factor of a commercial SPECT/CT system. Moreover, the noise level and the concentration recovery coefficient were evaluated as a function of the number of 3D-OSEM updates by using the SPECT/CT images of the reference geometry phantoms and those of a cold Jaszczak phantom with three hot spheres (16ml, 8ml and 4ml), respectively. The optimal choice of the number of 3D-OSEM updates was based on a compromise between the noise level achievable in the reconstructed SPECT images and the concentration recovery coefficients. The quantitative accuracy achievable was finally validated on a test phantom, where a spherical insert composed of two concentric spheres was used to simulate a lesion in a warm background. Our data confirm and extend previous observations. Using the calibration factor obtained with the cylindrical homogeneous phantom and the Jaszczak 16 ml sphere, the recovered activity in the test phantom was underestimated by -16.4% and -24.8%, respectively. Our work has led us to conclude that gamma camera calibration performed with large homogeneous phantom outperforms calibration executed with the Jaszczak 16ml sphere. Furthermore, the results obtained support the assumption that approximately 50 OSEM updates represent a good trade-off to reach convergence in small volumes, meanwhile minimizing the noise level.
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Affiliation(s)
- Emilio Mezzenga
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
- * E-mail:
| | - Vincenzo D’Errico
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Marco D’Arienzo
- National Institute of Ionizing Radiation Metrology, ENEA CR Casaccia,
Rome, Italy
| | - Lidia Strigari
- Laboratory of Medical Physics and Expert Systems, Regina Elena National
Cancer Institute, Rome, Italy
| | - Koutla Panagiota
- Department of Physics, Aristotle University of Thessaloniki,
Thessaloniki, Greece
| | - Federica Matteucci
- Nuclear Medicine Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Stefano Severi
- Nuclear Medicine Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Giovanni Paganelli
- Nuclear Medicine Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Andrew Fenwick
- National Physical Laboratory, Hampton Road, Teddington, United
Kingdom
| | - David Bianchini
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Francesco Marcocci
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
| | - Anna Sarnelli
- Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la
Cura dei Tumori (IRST) IRCCS, Meldola, Italy
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Esquinas PL, Uribe CF, Gonzalez M, Rodríguez-Rodríguez C, Häfeli UO, Celler A. Accuracy of Rhenium-188 SPECT/CT activity quantification for applications in radionuclide therapy using clinical reconstruction methods. Phys Med Biol 2017; 62:6379-6396. [PMID: 28726679 DOI: 10.1088/1361-6560/aa7926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The main applications of 188Re in radionuclide therapies include trans-arterial liver radioembolization and palliation of painful bone-metastases. In order to optimize 188Re therapies, the accurate determination of radiation dose delivered to tumors and organs at risk is required. Single photon emission computed tomography (SPECT) can be used to perform such dosimetry calculations. However, the accuracy of dosimetry estimates strongly depends on the accuracy of activity quantification in 188Re images. In this study, we performed a series of phantom experiments aiming to investigate the accuracy of activity quantification for 188Re SPECT using high-energy and medium-energy collimators. Objects of different shapes and sizes were scanned in Air, non-radioactive water (Cold-water) and water with activity (Hot-water). The ordered subset expectation maximization algorithm with clinically available corrections (CT-based attenuation, triple-energy window (TEW) scatter and resolution recovery was used). For high activities, the dead-time corrections were applied. The accuracy of activity quantification was evaluated using the ratio of the reconstructed activity in each object to this object's true activity. Each object's activity was determined with three segmentation methods: a 1% fixed threshold (for cold background), a 40% fixed threshold and a CT-based segmentation. Additionally, the activity recovered in the entire phantom, as well as the average activity concentration of the phantom background were compared to their true values. Finally, Monte-Carlo simulations of a commercial [Formula: see text]-camera were performed to investigate the accuracy of the TEW method. Good quantification accuracy (errors <10%) was achieved for the entire phantom, the hot-background activity concentration and for objects in cold background segmented with a 1% threshold. However, the accuracy of activity quantification for objects segmented with 40% threshold or CT-based methods decreased (errors >15%), mostly due to partial-volume effects. The Monte-Carlo simulations confirmed that TEW-scatter correction applied to 188Re, although practical, yields only approximate estimates of the true scatter.
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Affiliation(s)
- Pedro L Esquinas
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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