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Jessen L, Gustafsson J, Ljungberg M, Curkic-Kapidzic S, Imsirovic M, Sjögreen-Gleisner K. 3D printed non-uniform anthropomorphic phantoms for quantitative SPECT. EJNMMI Phys 2024; 11:8. [PMID: 38252205 PMCID: PMC10803701 DOI: 10.1186/s40658-024-00613-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 01/15/2024] [Indexed: 01/23/2024] Open
Abstract
BACKGROUND A 3D printing grid-based method was developed to construct anthropomorphic phantoms with non-uniform activity distributions, to be used for evaluation of quantitative SPECT images. The aims were to characterize the grid-based method and to evaluate its capability to provide realistically shaped phantoms with non-uniform activity distributions. METHODS Characterization of the grid structures was performed by printing grid-filled spheres. Evaluation was performed by micro-CT imaging to investigate the printing accuracy and by studying the modulation contrast ([Formula: see text]) in SPECT images for 177Lu and 99mTc as a function of the grid fillable-volume fraction (FVF) determined from weighing. The grid-based technique was applied for the construction of two kidney phantoms and two thyroid phantoms, designed using templates from the XCAT digital phantoms. The kidneys were constructed with a hollow outer container shaped as cortex, an inner grid-based structure representing medulla and a solid section representing pelvis. The thyroids consisted of two lobes printed as grid-based structures, with void hot spots within the lobes. The phantoms were filled with solutions of 177Lu (kidneys) or 99mTc (thyroids) and imaged with SPECT. For verification, Monte Carlo simulations of SPECT imaging were performed for activity distributions corresponding to those of the printed phantoms. Measured and simulated SPECT images were compared qualitatively and quantitatively. RESULTS Micro-CT images showed that printing inaccuracies were mainly uniform across the grid. The relationships between the FVF from weighing and [Formula: see text] were found to be linear (r = 0.9995 and r = 0.9993 for 177Lu and 99mTc, respectively). The FVF-deviations from the design were up to 15% for thyroids and 4% for kidneys, mainly related to possibilities of cleaning after printing. Measured and simulated SPECT images of kidneys and thyroids exhibited similar activity distributions and quantitative comparisons agreed well, thus verifying the grid-based method. CONCLUSIONS We find the grid-based technique useful for the provision of 3D printed, realistically shaped, phantoms with non-uniform activity distributions, which can be used for evaluation of different quantitative methods in SPECT imaging.
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Affiliation(s)
- Lovisa Jessen
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden.
| | | | | | - Selma Curkic-Kapidzic
- Medical Radiation Physics, Lund, Lund University, Lund, Sweden
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden
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Robinson AP, Calvert N, Tipping J, Denis-Bacelar AM, Ferreira KM, Lassmann M, Tran-Gia J. Development of a validation imaging dataset for Molecular Radiotherapy dosimetry multicenter intercomparison exercises based on anthropomorphic phantoms. Phys Med 2023; 109:102583. [PMID: 37062101 PMCID: PMC10165308 DOI: 10.1016/j.ejmp.2023.102583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 03/23/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023] Open
Abstract
Validation of a Molecular Radiotherapy (MRT) dosimetry system requires imaging data for which an accompanying "ground truth" pharmacokinetic model and absorbed dose calculation are known. METHODS We present a methodology for production of a validation dataset for image based 177Lu dotatate dosimetry calculations. A pharmacokinetic model is presented with activity concentrations corresponding to common imaging timepoints. Anthropomorphic 3D printed phantoms, corresponding to the organs at risk, have been developed to provide SPECT/CT and Whole Body imaging with known organ activities corresponding to common clinical timepoints. RESULTS Results for the accuracy of phantom filling reproduce the activity concentrations from the pharmacokinetic model for all timepoints and organs within measurement uncertainties, with a mean deviation of 0.6(8)%. The imaging dataset, ancillary data and phantoms designs are provided as a source of well characterized input data for the validation of clinical MRT dosimetry systems. CONCLUSIONS The combination of pharmacokinetic modelling with the use of anthropomorphic 3D printed phantoms are a promising procedure to provide data for the validation of Molecular Radiotherapy Dosimetry systems, allowing multicentre comparisons.
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Affiliation(s)
- Andrew P Robinson
- National Physical Laboratory, Teddington, TW11 0LW, United Kingdom; Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom; Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, United Kingdom.
| | - Nick Calvert
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom
| | - Jill Tipping
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom
| | | | | | - Michael Lassmann
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University Hospital Würzburg, Oberdürrbacher Str. 6, 97080 Würzburg, Germany
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Adam DP, Grudzinski J, Bormett I, Cox BL, Marsh IR, Bradshaw TJ, Harari PM, Bednarz B. Validation of Monte Carlo 131 I radiopharmaceutical dosimetry workflow using a 3D printed anthropomorphic head and neck phantom. Med Phys 2022; 49:5491-5503. [PMID: 35607296 PMCID: PMC9388595 DOI: 10.1002/mp.15699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 11/11/2022] Open
Abstract
Purpose Approximately 50% of head and neck cancer (HNC) patients will experience loco‐regional disease recurrence following initial courses of therapy. Retreatment with external beam radiotherapy (EBRT) is technically challenging and may be associated with a significant risk of irreversible damage to normal tissues. Radiopharmaceutical therapy (RPT) is a potential method to treat recurrent HNC in conjunction with EBRT. Phantoms are used to calibrate and add quantification to nuclear medicine images, and anthropomorphic phantoms can account for both the geometrical and material composition of the head and neck. In this study, we present the creation of an anthropomorphic, head and neck, nuclear medicine phantom, and its characterization for the validation of a Monte Carlo, SPECT image‐based, 131I RPT dosimetry workflow. Methods 3D‐printing techniques were used to create the anthropomorphic phantom from a patient CT dataset. Three 131I SPECT/CT imaging studies were performed using a homogeneous, Jaszczak, and an anthropomorphic phantom to quantify the SPECT images using a GE Optima NM/CT 640 with a high energy general purpose collimator. The impact of collimator detector response (CDR) modeling and volume‐based partial volume corrections (PVCs) upon the absorbed dose was calculated using an image‐based, Geant4 Monte Carlo RPT dosimetry workflow and compared against a ground truth scenario. Finally, uncertainties were quantified in accordance with recent EANM guidelines. Results The 3D‐printed anthropomorphic phantom was an accurate re‐creation of patient anatomy including bone. The extrapolated Jaszczak recovery coefficients were greater than that of the 3D‐printed insert (∼22.8 ml) for both the CDR and non‐CDR cases (with CDR: 0.536 vs. 0.493, non‐CDR: 0.445 vs. 0.426, respectively). Utilizing Jaszczak phantom PVCs, the absorbed dose was underpredicted by 0.7% and 4.9% without and with CDR, respectively. Utilizing anthropomorphic phantom recovery coefficient overpredicted the absorbed dose by 3% both with and without CDR. All dosimetry scenarios that incorporated PVC were within the calculated uncertainty of the activity. The uncertainties in the cumulative activity ranged from 23.6% to 106.4% for Jaszczak spheres ranging in volume from 0.5 to 16 ml. Conclusion The accuracy of Monte Carlo‐based dosimetry for 131I RPT in HNC was validated with an anthropomorphic phantom. In this study, it was found that Jaszczak‐based PVCs were sufficient. Future applications of the phantom could involve 3D printing and characterizing patient‐specific volumes for more personalized RPT dosimetry estimates.
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Affiliation(s)
- David P Adam
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, 53705
| | - Joseph Grudzinski
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, 53705
| | - Ian Bormett
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI, 53705
| | - Benjamin L Cox
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI, 53705
| | - Ian R Marsh
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, 53705
| | - Tyler J Bradshaw
- Department of Radiology, University of Wisconsin-Madison, Madison, WI, 53705
| | - Paul M Harari
- Department of Human Oncology, University of Wisconsin-Madison, Madison, WI, 53705
| | - Bryan Bednarz
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, 53705
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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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Ligonnet T, Pistone D, Auditore L, Italiano A, Amato E, Campennì A, Schaefer N, Boughdad S, Baldari S, Gnesin S. Simplified patient-specific renal dosimetry in 177Lu therapy: a proof of concept. Phys Med 2021; 92:75-85. [PMID: 34875425 DOI: 10.1016/j.ejmp.2021.11.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The aim of this proof-of-concept study is to propose a simplified personalized kidney dosimetry procedure in 177Lu peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors and metastatic prostate cancer. It relies on a single quantitative SPECT/CT acquisition and multiple radiometric measurements executed with a collimated external probe, properly directed on kidneys. METHODS We conducted a phantom study involving external count-rate measurements in an abdominal phantom setup filled with activity concentrations of 99mTc, reproducing patient-relevant organ effective half-lives occurring in 177Lu PRRT. GATE Monte Carlo (MC) simulations of the experiment, using 99mTc and 177Lu as sources, were performed. Furthermore, we tested this method via MC on a clinical case of 177Lu-DOTATATE PRRT with SPECT/CT images at three time points (2, 20 and 70 hrs), comparing a simplified kidney dosimetry, employing a single SPECT/CT and probe measurements at three time points, with the complete MC dosimetry. RESULTS The experimentally estimated kidney half-life with background subtraction applied was compatible within 3% with the expected value. The MC simulations of the phantom study, both with 99mTc and 177Lu, confirmed a similar level of accuracy. Concerning the clinical case, the simplified dosimetric method led to a kidney dose estimation compatible with the complete MC dosimetry within 6%, 12% and 2%, using respectively the SPECT/CT at 2, 20 and 70 hrs. CONCLUSIONS The proposed simplified procedure provided a satisfactory accuracy and would reduce the imaging required to derive the kidney absorbed dose to a unique quantitative SPECT/CT, with consequent benefits in terms of clinic workflows and patient comfort.
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Affiliation(s)
- Thomas Ligonnet
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Daniele Pistone
- MIFT Department, Università degli Studi di Messina, Messina, Italy; INFN Sezione di Catania, Catania, Italy.
| | - Lucrezia Auditore
- BIOMORF Department, Università degli Studi di Messina, Messina, Italy
| | - Antonio Italiano
- MIFT Department, Università degli Studi di Messina, Messina, Italy; INFN Sezione di Catania, Catania, Italy
| | - Ernesto Amato
- INFN Sezione di Catania, Catania, Italy; BIOMORF Department, Università degli Studi di Messina, Messina, Italy
| | - Alfredo Campennì
- BIOMORF Department, Università degli Studi di Messina, Messina, Italy; Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy
| | - Niklaus Schaefer
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Sarah Boughdad
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Sergio Baldari
- BIOMORF Department, Università degli Studi di Messina, Messina, Italy; Nuclear Medicine Unit, University Hospital "G. Martino", Messina, Italy
| | - Silvano Gnesin
- Institute of Radiation Physics, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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Della Gala G, Bardiès M, Tipping J, Strigari L. Overview of commercial treatment planning systems for targeted radionuclide therapy. Phys Med 2021; 92:52-61. [PMID: 34864422 DOI: 10.1016/j.ejmp.2021.11.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/23/2021] [Accepted: 11/12/2021] [Indexed: 10/19/2022] Open
Abstract
INTRODUCTION Targeted Radionuclide Therapy (TRT) is a branch of cancer medicine dealing with the therapeutic use of radioisotopes associated with biological vectors accumulating in the tumors/targets, indicated as Molecular Radiotherapy (MRT), or directly injected into the arteries that supply blood to liver tumour vasculature, indicated as Selective RT (SRT). The aim of this work is to offer a panoramic view on the increasing number of commercially-available TRT treatment planning systems (TPSs). MATERIALS AND METHODS A questionnaire was sent to manufacturers' representatives. Academic software were not considered. Questions were grouped as follows: general information, clinical workflow, calibration procedure, image processing/reconstruction, image registration and segmentation tools, time-activity curve (TAC) fitting and absorbed dose calculation. RESULTS All software reported have CE-marking. TPSs were divided between SRT-dedicated software [4] and MRT [5] dosimetry software. In SRT, since no kinetic process is involved, absorbed dose calculation does not require TAC fitting, and image registration is not fully developed in all TPS. All software requires a radionuclide-specific calibration. In SRT, a relative image calibration can be obtained by scaling the counts to a known activity. Automated VOI contouring and rigid/deformable propagation between different acquisitions time-points is implemented in most TPSs, although DICOM export is rare. Different TAC fits are available depending on the number of time-points. Voxel S-value and Local deposition methods are the most frequent dosimetric approaches; dose-voxel kernel convolution and semi-Monte Carlo method are also available. CONCLUSIONS Available TPSs allows performing personalized dosimetry in clinical practice. Individual variations in methodology/algorithms must be considered in the standardisation/harmonization processes.
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Affiliation(s)
- Giuseppe Della Gala
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Manuel Bardiès
- Département de Médecine Nucléaire, Institut Régional du Cancer de Montpellier (ICM), Montpellier F-34298, France; IRCM, UMR 1194 INSERM, Université de Montpellier and Institut Régional du Cancer de Montpellier (ICM), Montpellier F-34298, France
| | - Jill Tipping
- The Christie NHS Foundation Trust, Manchester, UK
| | - Lidia Strigari
- Department of Medical Physics, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.
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Tran-Gia J, Denis-Bacelar AM, Ferreira KM, Robinson AP, Calvert N, Fenwick AJ, Finocchiaro D, Fioroni F, Grassi E, Heetun W, Jewitt SJ, Kotzassarlidou M, Ljungberg M, McGowan DR, Scott N, Scuffham J, Gleisner KS, Tipping J, Wevrett J, Lassmann M. A multicentre and multi-national evaluation of the accuracy of quantitative Lu-177 SPECT/CT imaging performed within the MRTDosimetry project. EJNMMI Phys 2021; 8:55. [PMID: 34297218 PMCID: PMC8302709 DOI: 10.1186/s40658-021-00397-0] [Citation(s) in RCA: 29] [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: 04/26/2021] [Accepted: 06/21/2021] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Patient-specific dosimetry is required to ensure the safety of molecular radiotherapy and to predict response. Dosimetry involves several steps, the first of which is the determination of the activity of the radiopharmaceutical taken up by an organ/lesion over time. As uncertainties propagate along each of the subsequent steps (integration of the time-activity curve, absorbed dose calculation), establishing a reliable activity quantification is essential. The MRTDosimetry project was a European initiative to bring together expertise in metrology and nuclear medicine research, with one main goal of standardizing quantitative 177Lu SPECT/CT imaging based on a calibration protocol developed and tested in a multicentre inter-comparison. This study presents the setup and results of this comparison exercise. METHODS The inter-comparison included nine SPECT/CT systems. Each site performed a set of three measurements with the same setup (system, acquisition and reconstruction): (1) Determination of an image calibration for conversion from counts to activity concentration (large cylinder phantom), (2) determination of recovery coefficients for partial volume correction (IEC NEMA PET body phantom with sphere inserts), (3) validation of the established quantitative imaging setup using a 3D printed two-organ phantom (ICRP110-based kidney and spleen). In contrast to previous efforts, traceability of the activity measurement was required for each participant, and all participants were asked to calculate uncertainties for their SPECT-based activities. RESULTS Similar combinations of imaging system and reconstruction lead to similar image calibration factors. The activity ratio results of the anthropomorphic phantom validation demonstrate significant harmonization of quantitative imaging performance between the sites with all sites falling within one standard deviation of the mean values for all inserts. Activity recovery was underestimated for total kidney, spleen, and kidney cortex, while it was overestimated for the medulla. CONCLUSION This international comparison exercise demonstrates that harmonization of quantitative SPECT/CT is feasible when following very specific instructions of a dedicated calibration protocol, as developed within the MRTDosimetry project. While quantitative imaging performance demonstrates significant harmonization, an over- and underestimation of the activity recovery highlights the limitations of any partial volume correction in the presence of spill-in and spill-out between two adjacent volumes of interests.
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Affiliation(s)
- Johannes Tran-Gia
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany.
| | | | | | - Andrew P Robinson
- National Physical Laboratory, Teddington, UK
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
- The University of Manchester, Manchester, UK
| | - Nicholas Calvert
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
| | - Andrew J Fenwick
- National Physical Laboratory, Teddington, UK
- Cardiff University, Cardiff, UK
| | - 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
| | - Federica Fioroni
- 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
| | | | - Stephanie J Jewitt
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Maria Kotzassarlidou
- Nuclear Medicine Department, "THEAGENIO" Anticancer Hospital, Thessaloniki, Greece
| | | | - Daniel R McGowan
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Oncology, University of Oxford, Oxford, UK
| | - Nathaniel Scott
- Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - James Scuffham
- National Physical Laboratory, Teddington, UK
- Royal Surrey County Hospital, Guildford, UK
- Department of Physics, University of Surrey, Guildford, UK
| | | | - Jill Tipping
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Manchester, UK
| | - Jill Wevrett
- National Physical Laboratory, Teddington, UK
- Royal Surrey County Hospital, Guildford, UK
- Department of Physics, University of Surrey, Guildford, UK
| | - Michael Lassmann
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
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Taprogge J, Leek F, Schurrat T, Tran-Gia J, Vallot D, Bardiès M, Eberlein U, Lassmann M, Schlögl S, Vergara Gil A, Flux GD. Setting up a quantitative SPECT imaging network for a European multi-centre dosimetry study of radioiodine treatment for thyroid cancer as part of the MEDIRAD project. EJNMMI Phys 2020; 7:61. [PMID: 33030702 PMCID: PMC7544799 DOI: 10.1186/s40658-020-00332-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/29/2020] [Indexed: 12/29/2022] Open
Abstract
Background Differentiated thyroid cancer has been treated with radioiodine for almost 80 years, although controversial questions regarding radiation-related risks and the optimisation of treatment regimens remain unresolved. Multi-centre clinical studies are required to ensure recruitment of sufficient patients to achieve the statistical significance required to address these issues. Optimisation and standardisation of data acquisition and processing are necessary to ensure quantitative imaging and patient-specific dosimetry. Material and methods A European network of centres able to perform standardised quantitative imaging of radioiodine therapy of thyroid cancer patients was set-up within the EU consortium MEDIRAD. This network will support a concurrent series of clinical studies to determine accurately absorbed doses for thyroid cancer patients treated with radioiodine. Five SPECT(/CT) systems at four European centres were characterised with respect to their system volume sensitivity, recovery coefficients and dead time. Results System volume sensitivities of the Siemens Intevo systems (crystal thickness 3/8″) ranged from 62.1 to 73.5 cps/MBq. For a GE Discovery 670 (crystal thickness 5/8″) a system volume sensitivity of 92.2 cps/MBq was measured. Recovery coefficients measured on three Siemens Intevo systems show good agreement. For volumes larger than 10 ml, the maximum observed difference between recovery coefficients was found to be ± 0.02. Furthermore, dead-time coefficients measured on two Siemens Intevo systems agreed well with previously published dead-time values. Conclusions Results presented here provide additional support for the proposal to use global calibration parameters for cameras of the same make and model. This could potentially facilitate the extension of the imaging network for further dosimetry-based studies.
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Affiliation(s)
- Jan Taprogge
- Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton, SM2 5PT, UK. .,The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK.
| | - Francesca Leek
- Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton, SM2 5PT, UK.,The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Tino Schurrat
- Department of Nuclear Medicine, Philipps-University Marburg, Baldingerstrasse, 35043, Marburg, Germany
| | - Johannes Tran-Gia
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Delphine Vallot
- IUCT Oncopole, Av. Irène Joliot-Curie, 31100, Toulouse, France
| | - Manuel Bardiès
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, INSERM, Université Paul Sabatier, Toulouse, France
| | - Uta Eberlein
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Michael Lassmann
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Susanne Schlögl
- Department of Nuclear Medicine, University of Würzburg, Oberdürrbacher Str. 6, 97080, Würzburg, Germany
| | - Alex Vergara Gil
- Centre de Recherches en Cancérologie de Toulouse, UMR 1037, INSERM, Université Paul Sabatier, Toulouse, France
| | | | - Glenn D Flux
- Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton, SM2 5PT, UK.,The Institute of Cancer Research, 123 Old Brompton Road, London, SW7 3RP, UK
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Gear JI, Cummings C, Sullivan J, Cooper-Rayner N, Downs P, Murray I, Flux GD. Radioactive 3D printing for the production of molecular imaging phantoms. Phys Med Biol 2020; 65:175019. [PMID: 32640429 DOI: 10.1088/1361-6560/aba40e] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Quality control tests of molecular imaging systems are hampered by the complexity of phantom preparation. It is proposed that radioisotopes can be directly incorporated into photo-polymer resins. Use of the radio-polymer in a 3D printer allows phantoms with more complex and reliable activity distributions to be produced whilst simplifying source preparation. Initial tests have been performed to determine the practicality of integrating Tc-99m into a photo-polymer and example phantoms produced to test suitability for quality control. Samples of build and support resins were extracted from the print cartridges of an Objet30Pro Polyjet 3D printer. The response of the resin to external factors including ionising radiation, light and dilution with Tc-99m pertechnetate were explored. After success of the initial tests the radio-polymer was used in the production of different phantoms. Radionuclide dose calibrator and gamma camera acquisitions of the phantoms were used to test accuracy of activity concentration, print consistency, uniformity and heterogeneous reproducibility. Tomographic phantoms were also produced including a uniform hot sphere, a complex configuration of spheres and interlacing torus's and a hot rod phantom. The coefficient of variation between repeat prints of a 12 g disk phantom was 0.08%. Measured activity within the disks agreed to within 98 ± 2% of the expected activity based on initial resin concentration. Gamma camera integral uniformity measured across a 3D printed flood field phantom was 5.2% compared to 6.0% measured with a commercial Co-57 flood source. Heterogeneous distributions of activity were successfully reproduced for both 2D and 3D imaging phantoms. Count concentration across regions of heterogeneity agreed with the planned activity assigned to those regions on the phantom design. 3D printing of radioactive phantoms has been successfully demonstrated and is a promising application for quality control of Positron Emission Tomography and Single Photon Emission Computed Tomography systems.
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Taprogge J, Leek F, Flux GD. Physics aspects of setting up a multicenter clinical trial involving internal dosimetry of radioiodine treatment of differentiated thyroid cancer. THE QUARTERLY JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING : OFFICIAL PUBLICATION OF THE ITALIAN ASSOCIATION OF NUCLEAR MEDICINE (AIMN) [AND] THE INTERNATIONAL ASSOCIATION OF RADIOPHARMACOLOGY (IAR), [AND] SECTION OF THE SOCIETY OF... 2019; 63:271-277. [PMID: 31315346 DOI: 10.23736/s1824-4785.19.03202-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2024]
Abstract
The field of molecular radiotherapy is expanding rapidly, with the advent of many new radiotherapeutics for the treatment of common as well as for rare cancers. Treatment outcome is dependent on the absorbed doses delivered to target volumes and to healthy organs-at-risk, which are shown to vary widely from fixed administrations of activity. There have been significant developments in quantitative imaging and internal dosimetry in recent years, although clinical implementation of these methods has been slow in comparison with external beam radiotherapy, partly due to there being relatively few patients treated at single centers. Multicenter clinical trials are therefore essential to acquire the data required to ensure best practice and to develop the personalized treatment planning that this area is well suited to, due to the unrivalled opportunity to image the therapeutic drug in vivo. Initial preparation for such trials requires a significant effort in terms of resources and trial design. Imaging systems in participating centers must be characterized and set up for quantitative imaging to allow for collation of data. Data transfer for centralized processing is usually necessary but is hindered in some cases by data protection regulations and local logistics. Recent multicenter clinical trials involving radioiodine therapy have begun to establish the procedures necessary for quantitative SPECT imaging in a multicenter setting using standard and anthropomorphic phantoms. The establishment of national and international multicenter imaging and dosimetry networks will provide frameworks to develop and harmonize best practice with existing therapeutic procedures and to ensure rapid and optimized clinical implementation of new radiotherapeutics across all centers of excellence that offer molecular radiotherapy. This will promote networks and collaborations that can provide a sound basis for further developments and will ensure that nuclear medicine maintains a key role in future developments.
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Affiliation(s)
- Jan Taprogge
- Joint Department of Physics, Royal Marsden NHS Foundation Trust, Sutton, UK -
- The Institute of Cancer Research, London, UK -
| | - Francesca Leek
- Joint Department of Physics, Royal Marsden NHS Foundation Trust, Sutton, UK
- The Institute of Cancer Research, London, UK
| | - Glenn D Flux
- Joint Department of Physics, Royal Marsden NHS Foundation Trust, Sutton, UK
- The Institute of Cancer Research, London, UK
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Positional dependence of activity determination in single photon emission computed tomography. Nucl Med Commun 2019; 40:865-872. [PMID: 31136536 PMCID: PMC6635063 DOI: 10.1097/mnm.0000000000001034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Accurate image quantification requires accurate calibration of the detector and is vital if dosimetry is to be performed in molecular radiotherapy. A dependence on the position of calibration has been observed in single photon emission computed tomography images when attenuation correction (AC) and scatter correction are applied. This work investigates the origin of this dependence in single photon emission computed tomography scans of phantom inserts filled with 177Lu solution. A 113 ml sphere and inserts representing a mathematical model of a spleen and an anatomical model of a patient spleen were imaged at the centre and edge of elliptical phantoms. For these inserts, the difference in calibration factor between the positions was around 10% for images reconstructed with AC and triple energy window scatter correction. A combination of experimental imaging and Monte Carlo simulation was used to isolate possible causes due to imaging or reconstruction in turn. Inconsistent application of AC between different reconstruction systems was identified as the origin of the positional dependence.
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