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Schraven S, Brück R, Rosenhain S, Lemainque T, Heines D, Noormohammadian H, Pabst O, Lederle W, Gremse F, Kiessling F. CT- and MRI-Aided Fluorescence Tomography Reconstructions for Biodistribution Analysis. Invest Radiol 2024; 59:504-512. [PMID: 38038691 DOI: 10.1097/rli.0000000000001052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
OBJECTIVES Optical fluorescence imaging can track the biodistribution of fluorophore-labeled drugs, nanoparticles, and antibodies longitudinally. In hybrid computed tomography-fluorescence tomography (CT-FLT), CT provides the anatomical information to generate scattering and absorption maps supporting a 3-dimensional reconstruction from the raw optical data. However, given the CT's limited soft tissue contrast, fluorescence reconstruction and quantification can be inaccurate and not sufficiently detailed. Magnetic resonance imaging (MRI) can overcome these limitations and extend the options for tissue characterization. Thus, we aimed to establish a hybrid CT-MRI-FLT approach for whole-body imaging and compared it with CT-FLT. MATERIALS AND METHODS The MRI-based hybrid imaging approaches were established first by scanning a water and coconut oil-filled phantom, second by quantifying Cy7 concentrations of inserts in dead mice, and finally by analyzing the biodistribution of AF750-labeled immunoglobulins (IgG, IgA) in living SKH1 mice. Magnetic resonance imaging, acquired with a fat-water-separated mDixon sequence, CT, and FLT were co-registered using markers in the mouse holder frame filled with white petrolatum, which was solid, stable, and visible in both modalities. RESULTS Computed tomography-MRI fusion was confirmed by comparing the segmentation agreement using Dice scores. Phantom segmentations showed good agreement, after correction for gradient linearity distortion and chemical shift. Organ segmentations in dead and living mice revealed adequate agreement for fusion. Marking the mouse holder frame and the successful CT-MRI fusion enabled MRI-FLT as well as CT-MRI-FLT reconstructions. Fluorescence tomography reconstructions supported by CT, MRI, or CT-MRI were comparable in dead mice with 60 pmol fluorescence inserts at different locations. Although standard CT-FLT reconstruction only considered general values for soft tissue, skin, lung, fat, and bone scattering, MRI's more versatile soft tissue contrast enabled the additional consideration of liver, kidneys, and brain. However, this did not change FLT reconstructions and quantifications significantly, whereas for extending scattering maps, it was important to accurately segment the organs and the entire mouse body. The various FLT reconstructions also provided comparable results for the in vivo biodistribution analyses with fluorescent immunoglobulins. However, MRI additionally enabled the visualization of gallbladder, thyroid, and brain. Furthermore, segmentations of liver, spleen, and kidney were more reliable due to better-defined contours than in CT. Therefore, the improved segmentations enabled better assignment of fluorescence signals and more differentiated conclusions with MRI-FLT. CONCLUSIONS Whole-body CT-MRI-FLT was implemented as a novel trimodal imaging approach, which allowed to more accurately assign fluorescence signals, thereby significantly improving pharmacokinetic analyses.
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Affiliation(s)
- Sarah Schraven
- From the Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany (S.S., R.B., S.R., T.L., D.H., W.L., F.G., F.K.); Institute of Molecular Medicine, RWTH Aachen University, Aachen, Germany (H.N., O.P.); Gremse-IT GmbH, Aachen, Germany (S.R., F.G.); Department for Diagnostic and Interventional Radiology, RWTH Aachen University, Aachen, Germany (T.L.); Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany (F.K.); and Fraunhofer MEVIS, Institute for Medical Image Computing, Aachen, Germany (F.K.)
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Gustafsson J, Taprogge J. Future trends for patient-specific dosimetry methodology in molecular radiotherapy. Phys Med 2023; 115:103165. [PMID: 37880071 DOI: 10.1016/j.ejmp.2023.103165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
Molecular radiotherapy is rapidly expanding, and new radiotherapeutics are emerging. The majority of treatments is still performed using empirical fixed activities and not tailored for individual patients. Molecular radiotherapy dosimetry is often seen as a promising candidate that would allow personalisation of treatments as outcome should ultimately depend on the absorbed doses delivered and not the activities administered. The field of molecular radiotherapy dosimetry has made considerable progress towards the feasibility of routine clinical dosimetry with reasonably accurate absorbed-dose estimates for a range of molecular radiotherapy dosimetry applications. A range of challenges remain with respect to the accurate quantification, assessment of time-integrated activity and absorbed dose estimation. In this review, we summarise a range of technological and methodological advancements, mainly focussed on beta-emitting molecular radiotherapeutics, that aim to improve molecular radiotherapy dosimetry to achieve accurate, reproducible, and streamlined dosimetry. We describe how these new technologies can potentially improve the often time-consuming considered process of dosimetry and provide suggestions as to what further developments might be required.
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Affiliation(s)
| | - Jan Taprogge
- National Radiotherapy Trials Quality Assurance (RTTQA) Group, Joint Department of Physics, Royal Marsden NHSFT, Downs Road, Sutton SM2 5PT, United Kingdom; The Institute of Cancer Research, 123 Old Brompton Road, London SW7 3RP, United Kingdom
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Li Z, Benabdallah N, Abou DS, Baumann BC, Dehdashti F, Ballard DH, Liu J, Jammalamadaka U, Laforest R, Wahl RL, Thorek DLJ, Jha AK. A Projection-Domain Low-Count Quantitative SPECT Method for α-Particle-Emitting Radiopharmaceutical Therapy. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2023; 7:62-74. [PMID: 37201111 PMCID: PMC10191330 DOI: 10.1109/trpms.2022.3175435] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Single-photon emission-computed tomography (SPECT) provides a mechanism to estimate regional isotope uptake in lesions and at-risk organs after administration of α-particle-emitting radiopharmaceutical therapies (α-RPTs). However, this estimation task is challenging due to the complex emission spectra, the very low number of detected counts (~20 times lower than in conventional SPECT), the impact of stray-radiation-related noise at these low counts, and the multiple image-degrading processes in SPECT. The conventional reconstruction-based quantification methods are observed to be erroneous for α-RPT SPECT. To address these challenges, we developed a low-count quantitative SPECT (LC-QSPECT) method that directly estimates the regional activity uptake from the projection data (obviating the reconstruction step), compensates for stray-radiation-related noise, and accounts for the radioisotope and SPECT physics, including the isotope spectra, scatter, attenuation, and collimator-detector response, using a Monte Carlo-based approach. The method was validated in the context of 3-D SPECT with 223Ra, a commonly used radionuclide for α-RPT. Validation was performed using both realistic simulation studies, including a virtual clinical trial, and synthetic and 3-D-printed anthropomorphic physical-phantom studies. Across all studies, the LC-QSPECT method yielded reliable regional-uptake estimates and outperformed the conventional ordered subset expectation-maximization (OSEM)-based reconstruction and geometric transfer matrix (GTM)-based post-reconstruction partial-volume compensation methods. Furthermore, the method yielded reliable uptake across different lesion sizes, contrasts, and different levels of intralesion heterogeneity. Additionally, the variance of the estimated uptake approached the Cramér-Rao bound-defined theoretical limit. In conclusion, the proposed LC-QSPECT method demonstrated the ability to perform reliable quantification for α-RPT SPECT.
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Affiliation(s)
- Zekun Li
- Department of Biomedical Engineering, Washington University, St. Louis, MO 63130 USA
| | - Nadia Benabdallah
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Diane S Abou
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Brian C Baumann
- Department of Radiation Oncology, Washington University, St. Louis, MO 63110 USA
| | - Farrokh Dehdashti
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - David H Ballard
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Jonathan Liu
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Uday Jammalamadaka
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Richard Laforest
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Richard L Wahl
- Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63110 USA
| | - Daniel L J Thorek
- Department of Biomedical Engineering, the Mallinckrodt Institute of Radiology, and the Program in Quantitative Molecular Therapeutics, Washington University, St. Louis, MO 63110 USA
| | - Abhinav K Jha
- Department of Biomedical Engineering and the Mallinckrodt Institute of Radiology, Washington University, St. Louis, MO 63130 USA
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A Narrative Review of 99mTc-Aprotinin in the Diagnosis of Cardiac Amyloidosis and a New Life for an Unfairly Abandoned Drug. Biomedicines 2022; 10:biomedicines10061377. [PMID: 35740399 PMCID: PMC9219762 DOI: 10.3390/biomedicines10061377] [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] [Received: 04/27/2022] [Revised: 05/26/2022] [Accepted: 06/07/2022] [Indexed: 11/17/2022] Open
Abstract
Several studies investigated the use of 99mTc-labelled Aprotinin as an amyloid seeker some years ago. In vitro tests showed high binding affinity for several types of amyloid fibrils accompanied by an excellent specificity. Initial human studies demonstrated good accuracy in detecting cardiac involvement. Scintigraphy results were confirmed in a group of 28 endomyocardial biopsies. Unfortunately, clinical studies were halted because of a temporary suspension of the vector protein (Trasylol) and public health concerns over prion contamination of the bovine origin compound. To obviate these limitations, efforts have been made to label a recombinant Aprotinin with 99mTc, which exhibits the same affinity for h-insulin fibrils. With the aim of developing a PET tracer, the same recombinant protein was labeled with Gallium. The introduction of a bifunctional chelator did not affect fibril affinity. Finally, a synthetic peptidic fragment, the cyclic 30-51 SS, was synthetized. After direct technetium labeling, an impressive increase in affinity was demonstrated. This peptide appears to be a potential candidate for Gallium labeling through a bifunctional chelator for PET imaging.
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Toczek J, Riou L. Considerations on PET/MR imaging of carotid plaque inflammation with 68Ga-Pentixafor. J Nucl Cardiol 2022; 29:503-505. [PMID: 32914318 DOI: 10.1007/s12350-020-02354-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Jakub Toczek
- Cardiovascular Molecular Imaging Laboratory, Section of Cardiovascular Medicine and Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT, 06511, USA
| | - Laurent Riou
- Laboratoire Radiopharmaceutiques Biocliniques, Faculté de Médecine de Grenoble, UMR UGA - INSERM U1039, Grenoble, France.
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Maduraiveeran H, Raja K, Chinnasamy A. Antiproliferative and antioxidant properties of nematocysts crude venom from jellyfish Acromitus flagellatus against human cancer cell lines. Saudi J Biol Sci 2021; 28:1954-1961. [PMID: 33732081 PMCID: PMC7938135 DOI: 10.1016/j.sjbs.2020.12.047] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/16/2020] [Accepted: 12/24/2020] [Indexed: 01/05/2023] Open
Abstract
This study aimed to investigate the antiproliferative and antioxidant properties of crude venom from the nematocyst of Jellyfish Acromitus flagellates on human lung cancer (A549) and liver cancer (HepG2) cell lines. The prepared crude venom was subjected to analyses of the biochemical constituents, protein profiles, antioxidant and anticancer activities by standard methods. The extracted venom was pale-yellow in color and viscous/sticky. The biochemical composition such as, protein (1.547 mg/ml), lipid (0.039 mg/ml) and carbohydrate (0.028 mg/ml) was estimated. Protein profiles were determined by SDS PAGE, the result revealed that the molecular weight range from 205 - 3.5 kDa. The free radical scavenging activity was analyzed by the reducing potential (56.36%), DPPH (72.47%), hydroxyl (68.50%), superoxide anion (65.75%), and nitric oxide (33.04%). The cell viability was observed by using different concentrations (20 to 100 µg/ml) of crude venom on A549 and HepG2 cancer cell lines and the IC50 values were recorded in (60 μg/ml and 40 μg/ml) respectively, while it had none cytotoxic effects on Vero cell line up to the concentration of 90 μg/ml. These results suggest that crude venom from nematocyst of A. flagellatus possesses anti-cancer activity and able to develop novel drugs on marine-derived compounds.
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Affiliation(s)
- Hemavathi Maduraiveeran
- Unit of Tissue Culture and Aquaculture, Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
| | - Kavitha Raja
- Unit of Tissue Culture and Aquaculture, Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
| | - Arulvasu Chinnasamy
- Unit of Tissue Culture and Aquaculture, Department of Zoology, University of Madras, Guindy Campus, Chennai 600 025, Tamil Nadu, India
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Akerele MI, Karakatsanis NA, Deidda D, Cal-Gonzalez J, Forsythe RO, Dweck MR, Syed M, Newby DE, Aykroyd RG, Sourbron S, Tsoumpas C. Comparison of Correction Techniques for the Spill in Effect in Emission Tomography. IEEE TRANSACTIONS ON RADIATION AND PLASMA MEDICAL SCIENCES 2020; 4:422-432. [PMID: 33542967 DOI: 10.1109/trpms.2020.2980443] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In positron emission tomography (PET) imaging, accurate clinical assessment is often affected by the partial volume effect (PVE) leading to overestimation (spill-in) or underestimation (spill-out) of activity in various small regions. The spill-in correction, in particular, can be very challenging when the target region is close to a hot background region. Therefore, this study evaluates and compares the performance of various recently developed spill-in correction techniques, namely: background correction (BC), local projection (LP), and hybrid kernelized (HKEM) methods. We used a simulated digital phantom and [18F]-NaF PET data of three patients with abdominal aortic aneurysms (AAA) acquired with Siemens Biograph mMR™ and mCT™ scanners respectively. Region of Interest (ROI) analysis was performed and the extracted SUV mean , SUV max and target-to-background ratio (TBR) scores were compared. Results showed substantial spill-in effects from hot regions to targeted regions, which are more prominent in small structures. The phantom experiment demonstrated the feasibility of spill-in correction with all methods. For the patient data, large differences in SUV mean , SUV max and TBR max scores were observed between the ROIs drawn over the entire aneurysm and ROIs excluding some regions close to the bone. Overall, BC yielded the best performance in spill-in correction in both phantom and patient studies.
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Affiliation(s)
- Mercy I Akerele
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Department of Radiology, Weil Cornell Medical College of Cornell University, NY, USA
| | - Nicolas A Karakatsanis
- Department of Radiology, Weil Cornell Medical College of Cornell University, NY, USA; Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, NY
| | - Daniel Deidda
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Department of Statistics, University of Leeds, UK; Nuclear Medicine Imaging, Medical Radiation Physics, National Physical Laboratory, London, UK
| | | | | | | | | | | | | | - Steven Sourbron
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK
| | - Charalampos Tsoumpas
- Biomedical Imaging Science Department, Faculty of Medicine and Health, University of Leeds, UK; Biomedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, NY
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Rimoldi O. Striving to improve 82Rubidium PET MPI accuracy. J Nucl Cardiol 2019; 26:1943-1945. [PMID: 30136035 DOI: 10.1007/s12350-018-1419-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 01/31/2023]
Affiliation(s)
- Ornella Rimoldi
- IBFM Consiglio Nazionale delle Ricerche Segrate, Via Fratelli Cervi, 93, 20090, Segrate, Italy.
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AI-based applications in hybrid imaging: how to build smart and truly multi-parametric decision models for radiomics. Eur J Nucl Med Mol Imaging 2019; 46:2673-2699. [PMID: 31292700 DOI: 10.1007/s00259-019-04414-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022]
Abstract
INTRODUCTION The quantitative imaging features (radiomics) that can be obtained from the different modalities of current-generation hybrid imaging can give complementary information with regard to the tumour environment, as they measure different morphologic and functional imaging properties. These multi-parametric image descriptors can be combined with artificial intelligence applications into predictive models. It is now the time for hybrid PET/CT and PET/MRI to take the advantage offered by radiomics to assess the added clinical benefit of using multi-parametric models for the personalized diagnosis and prognosis of different disease phenotypes. OBJECTIVE The aim of the paper is to provide an overview of current challenges and available solutions to translate radiomics into hybrid PET-CT and PET-MRI imaging for a smart and truly multi-parametric decision model.
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Meerwein CM, Pizzuto DA, Vital D, Morand GB, Stolzmann P, Huber GF, Huellner MW. Use of MRI and FDG-PET/CT to predict fixation of advanced hypopharyngeal squamous cell carcinoma to prevertebral space. Head Neck 2018; 41:503-510. [DOI: 10.1002/hed.25431] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 07/24/2018] [Accepted: 09/21/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Christian M. Meerwein
- Department of Otorhinolaryngology, Head & Neck Surgery; University Hospital Zurich; Zurich Switzerland
| | - Daniele A. Pizzuto
- Department of Nuclear Medicine; University Hospital Zurich/University of Zurich; Zurich Switzerland
- Instituto di Medicina Nucleare, Università Cattolica del Sacro Cuore; Rome Italy
| | - Domenic Vital
- Department of Otorhinolaryngology, Head & Neck Surgery; University Hospital Zurich; Zurich Switzerland
| | - Grégoire B. Morand
- Department of Otorhinolaryngology, Head & Neck Surgery; University Hospital Zurich; Zurich Switzerland
| | - Paul Stolzmann
- Department of Nuclear Medicine; University Hospital Zurich/University of Zurich; Zurich Switzerland
| | - Gerhard F. Huber
- Department of Otorhinolaryngology; Kantonsspital St. Gallen; St. Gallen Switzerland
| | - Martin W. Huellner
- Department of Nuclear Medicine; University Hospital Zurich/University of Zurich; Zurich Switzerland
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Cal-Gonzalez J, Li X, Heber D, Rausch I, Moore SC, Schäfers K, Hacker M, Beyer T. Partial volume correction for improved PET quantification in 18F-NaF imaging of atherosclerotic plaques. J Nucl Cardiol 2018; 25:1742-1756. [PMID: 28176255 PMCID: PMC6153866 DOI: 10.1007/s12350-017-0778-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 12/16/2016] [Indexed: 11/15/2022]
Abstract
BACKGROUND Accurate quantification of plaque imaging using 18F-NaF PET requires partial volume correction (PVC). METHODS PVC of PET data was implemented by the use of a local projection (LP) method. LP-based PVC was evaluated with an image quality (NEMA) and with a thorax phantom with "plaque-type" lesions of 18-36 mL. The validated PVC method was then applied to a cohort of 17 patients, each with at least one plaque in the carotid or ascending aortic arteries. In total, 51 calcified (HU > 110) and 16 non-calcified plaque lesions (HU < 110) were analyzed. The lesion-to-background ratio (LBR) and the relative change of LBR (ΔLBR) were measured on PET. RESULTS Following PVC, LBR of the spheres (NEMA phantom) was within 10% of the original values. LBR of the thoracic lesions increased by 155% to 440% when the LP-PVC method was applied to the PET images. In patients, PVC increased the LBR in both calcified [mean = 78% (-8% to 227%)] and non-calcified plaques [mean = 41%, (-9%-104%)]. CONCLUSIONS PVC helps to improve LBR of plaque-type lesions in both phantom studies and clinical patients. Better results were obtained when the PVC method was applied to images reconstructed with point spread function modeling.
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Affiliation(s)
- Jacobo Cal-Gonzalez
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria.
| | - Xiang Li
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Daniel Heber
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Ivo Rausch
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria
| | - Stephen C Moore
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women's Hospital, Boston, MA, USA
| | - Klaus Schäfers
- European Institute for Molecular Imaging, University of Münster, Münster, Germany
| | - Marcus Hacker
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Beyer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, General Hospital Vienna, Waehringer Guertel 18-20/4L, 1090, Vienna, Austria
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Cal-González J, Tsoumpas C, Lassen ML, Rasul S, Koller L, Hacker M, Schäfers K, Beyer T. Impact of motion compensation and partial volume correction for 18F-NaF PET/CT imaging of coronary plaque. Phys Med Biol 2017; 63:015005. [PMID: 29240557 DOI: 10.1088/1361-6560/aa97c8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent studies have suggested that 18F-NaF-PET enables visualization and quantification of plaque micro-calcification in the coronary tree. However, PET imaging of plaque calcification in the coronary arteries is challenging because of the respiratory and cardiac motion as well as partial volume effects. The objective of this work is to implement an image reconstruction framework, which incorporates compensation for respiratory as well as cardiac motion (MoCo) and partial volume correction (PVC), for cardiac 18F-NaF PET imaging in PET/CT. We evaluated the effect of MoCo and PVC on the quantification of vulnerable plaques in the coronary arteries. Realistic simulations (Biograph TPTV, Biograph mCT) and phantom acquisitions (Biograph mCT) were used for these evaluations. Different uptake values in the calcified plaques were evaluated in the simulations, while three 'plaque-type' lesions of 36, 31 and 18 mm3 were included in the phantom experiments. After validation, the MoCo and PVC methods were applied in four pilot NaF-PET patient studies. In all cases, the MoCo-based image reconstruction was performed using the STIR software. The PVC was obtained from a local projection (LP) method, previously evaluated in preclinical and clinical PET. The results obtained show a significant increase of the measured lesion-to-background ratios (LBR) in the MoCo + PVC images. These ratios were further enhanced when using directly the tissue-activities from the LP method, making this approach more suitable for the quantitative evaluation of coronary plaques. When using the LP method on the MoCo images, LBR increased between 200% and 1119% in the simulated data, between 212% and 614% in the phantom experiments and between 46% and 373% in the plaques with positive uptake observed in the pilot patients. In conclusion, we have built and validated a STIR framework incorporating MoCo and PVC for 18F-NaF PET imaging of coronary plaques. First results indicate an improved quantification of plaque-type lesions.
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Affiliation(s)
- J Cal-González
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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Chan C, Liu H, Grobshtein Y, Stacy MR, Sinusas AJ, Liu C. Noise suppressed partial volume correction for cardiac SPECT/CT. Med Phys 2017; 43:5225. [PMID: 27587054 DOI: 10.1118/1.4961391] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Partial volume correction (PVC) methods typically improve quantification at the expense of increased image noise and reduced reproducibility. In this study, the authors developed a novel voxel-based PVC method that incorporates anatomical knowledge to improve quantification while suppressing noise for cardiac SPECT/CT imaging. METHODS In the proposed method, the SPECT images were first reconstructed using anatomical-based maximum a posteriori (AMAP) with Bowsher's prior to penalize noise while preserving boundaries. A sequential voxel-by-voxel PVC approach (Yang's method) was then applied on the AMAP reconstruction using a template response. This template response was obtained by forward projecting a template derived from a contrast-enhanced CT image, and then reconstructed using AMAP to model the partial volume effects (PVEs) introduced by both the system resolution and the smoothing applied during reconstruction. To evaluate the proposed noise suppressed PVC (NS-PVC), the authors first simulated two types of cardiac SPECT studies: a (99m)Tc-tetrofosmin myocardial perfusion scan and a (99m)Tc-labeled red blood cell (RBC) scan on a dedicated cardiac multiple pinhole SPECT/CT at both high and low count levels. The authors then applied the proposed method on a canine equilibrium blood pool study following injection with (99m)Tc-RBCs at different count levels by rebinning the list-mode data into shorter acquisitions. The proposed method was compared to MLEM reconstruction without PVC, two conventional PVC methods, including Yang's method and multitarget correction (MTC) applied on the MLEM reconstruction, and AMAP reconstruction without PVC. RESULTS The results showed that the Yang's method improved quantification, however, yielded increased noise and reduced reproducibility in the regions with higher activity. MTC corrected for PVE on high count data with amplified noise, although yielded the worst performance among all the methods tested on low-count data. AMAP effectively suppressed noise and reduced the spill-in effect in the low activity regions. However it was unable to reduce the spill-out effect in high activity regions. NS-PVC yielded superior performance in terms of both quantitative assessment and visual image quality while improving reproducibility. CONCLUSIONS The results suggest that NS-PVC may be a promising PVC algorithm for application in low-dose protocols, and in gated and dynamic cardiac studies with low counts.
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Affiliation(s)
- Chung Chan
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520
| | - Hui Liu
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520 and Key Laboratory of Particle and Radiation Imaging (Tsinghua University), Ministry of Education, Beijing 100084, China
| | | | - Mitchel R Stacy
- Department of Internal Medicine, Yale University, New Haven, Connecticut 06520
| | - Albert J Sinusas
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520 and Department of Internal Medicine, Yale University, New Haven, Connecticut 06520
| | - Chi Liu
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut 06520
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14
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Xie T, Zaidi H. Development of computational small animal models and their applications in preclinical imaging and therapy research. Med Phys 2016; 43:111. [PMID: 26745904 DOI: 10.1118/1.4937598] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.
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Affiliation(s)
- Tianwu Xie
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211, Switzerland
| | - Habib Zaidi
- Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, Geneva 4 CH-1211, Switzerland; Geneva Neuroscience Center, Geneva University, Geneva CH-1205, Switzerland; and Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen 9700 RB, The Netherlands
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Cal-González J, Moore SC, Park MA, Herraiz JL, Vaquero JJ, Desco M, Udias JM. Improved quantification for local regions of interest in preclinical PET imaging. Phys Med Biol 2015; 60:7127-49. [PMID: 26334312 PMCID: PMC4593622 DOI: 10.1088/0031-9155/60/18/7127] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In Positron Emission Tomography, there are several causes of quantitative inaccuracy, such as partial volume or spillover effects. The impact of these effects is greater when using radionuclides that have a large positron range, e.g. (68)Ga and (124)I, which have been increasingly used in the clinic. We have implemented and evaluated a local projection algorithm (LPA), originally evaluated for SPECT, to compensate for both partial-volume and spillover effects in PET. This method is based on the use of a high-resolution CT or MR image, co-registered with a PET image, which permits a high-resolution segmentation of a few tissues within a volume of interest (VOI) centered on a region within which tissue-activity values need to be estimated. The additional boundary information is used to obtain improved activity estimates for each tissue within the VOI, by solving a simple inversion problem. We implemented this algorithm for the preclinical Argus PET/CT scanner and assessed its performance using the radionuclides (18)F, (68)Ga and (124)I. We also evaluated and compared the results obtained when it was applied during the iterative reconstruction, as well as after the reconstruction as a postprocessing procedure. In addition, we studied how LPA can help to reduce the 'spillover contamination', which causes inaccurate quantification of lesions in the immediate neighborhood of large, 'hot' sources. Quantification was significantly improved by using LPA, which provided more accurate ratios of lesion-to-background activity concentration for hot and cold regions. For (18)F, the contrast was improved from 3.0 to 4.0 in hot lesions (when the true ratio was 4.0) and from 0.16 to 0.06 in cold lesions (true ratio = 0.0), when using the LPA postprocessing. Furthermore, activity values estimated within the VOI using LPA during reconstruction were slightly more accurate than those obtained by post-processing, while also visually improving the image contrast and uniformity within the VOI.
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Affiliation(s)
- J. Cal-González
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
| | - S. C. Moore
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. Boston, USA
| | - M.-A. Park
- Division of Nuclear Medicine, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. Boston, USA
| | - J. L. Herraiz
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
- Madrid-MIT M+Visión Consortium, Research Lab. of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - J. J. Vaquero
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
| | - M. Desco
- Departamento de Bioingeniería e Ingeniería Aeroespacial, Universidad Carlos III de Madrid, Spain
- Unidad de Medicina y Cirugía Experimental, Hospital General Universitario Gregorio Marañón, CIBERSAM, Madrid, Spain
| | - J. M. Udias
- Grupo de Física Nuclear, Dpto. de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, CEI Moncloa, Spain
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Cal-González J, Moore SC, Park MA, Herraiz JL, Vaquero JJ, Desco M, Udias JM. Improved quantification for local regions of interest in preclinical PET imaging. Phys Med Biol 2015. [DOI: https://doi.org/10.1088/0031-9155/60/18/7127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Könik A, Kupinski M, Pretorius PH, King MA, Barrett HH. Comparison of the scanning linear estimator (SLE) and ROI methods for quantitative SPECT imaging. Phys Med Biol 2015; 60:6479-94. [PMID: 26247228 DOI: 10.1088/0031-9155/60/16/6479] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In quantitative emission tomography, tumor activity is typically estimated from calculations on a region of interest (ROI) identified in the reconstructed slices. In these calculations, unpredictable bias arising from the null functions of the imaging system affects ROI estimates. The magnitude of this bias depends upon the tumor size and location. In prior work it has been shown that the scanning linear estimator (SLE), which operates on the raw projection data, is an unbiased estimator of activity when the size and location of the tumor are known. In this work, we performed analytic simulation of SPECT imaging with a parallel-hole medium-energy collimator. Distance-dependent system spatial resolution and non-uniform attenuation were included in the imaging simulation. We compared the task of activity estimation by the ROI and SLE methods for a range of tumor sizes (diameter: 1-3 cm) and activities (contrast ratio: 1-10) added to uniform and non-uniform liver backgrounds. Using the correct value for the tumor shape and location is an idealized approximation to how task estimation would occur clinically. Thus we determined how perturbing this idealized prior knowledge impacted the performance of both techniques. To implement the SLE for the non-uniform background, we used a novel iterative algorithm for pre-whitening stationary noise within a compact region. Estimation task performance was compared using the ensemble mean-squared error (EMSE) as the criterion. The SLE method performed substantially better than the ROI method (i.e. EMSE(SLE) was 23-174 times lower) when the background is uniform and tumor location and size are known accurately. The variance of the SLE increased when a non-uniform liver texture was introduced but the EMSE(SLE) continued to be 5-20 times lower than the ROI method. In summary, SLE outperformed ROI under almost all conditions that we tested.
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Affiliation(s)
- Arda Könik
- Department of Radiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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Yan J, Lim JCS, Townsend DW. MRI-guided brain PET image filtering and partial volume correction. Phys Med Biol 2015; 60:961-76. [DOI: 10.1088/0031-9155/60/3/961] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Burg S, Dupas A, Stute S, Dieudonné A, Huet P, Le Guludec D, Buvat I. Partial volume effect estimation and correction in the aortic vascular wall in PET imaging. Phys Med Biol 2013; 58:7527-42. [PMID: 24099932 DOI: 10.1088/0031-9155/58/21/7527] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with (18)FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied.
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Affiliation(s)
- S Burg
- APHP-Service de médecine nucléaire, Hôpital Bichat-Claude-Bernard, F-75018 Paris, France
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Ben Bouallègue F, Crouzet JF, Dubois A, Buvat I, Mariano-Goulart D. Least-squares dual characterization for ROI assessment in emission tomography. Phys Med Biol 2013; 58:4175-94. [PMID: 23715413 DOI: 10.1088/0031-9155/58/12/4175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Our aim is to describe an original method for estimating the statistical properties of regions of interest (ROIs) in emission tomography. Drawn upon the works of Louis on the approximate inverse, we propose a dual formulation of the ROI estimation problem to derive the ROI activity and variance directly from the measured data without any image reconstruction. The method requires the definition of an ROI characteristic function that can be extracted from a co-registered morphological image. This characteristic function can be smoothed to optimize the resolution-variance tradeoff. An iterative procedure is detailed for the solution of the dual problem in the least-squares sense (least-squares dual (LSD) characterization), and a linear extrapolation scheme is described to compensate for sampling partial volume effect and reduce the estimation bias (LSD-ex). LSD and LSD-ex are compared with classical ROI estimation using pixel summation after image reconstruction and with Huesman's method. For this comparison, we used Monte Carlo simulations (GATE simulation tool) of 2D PET data of a Hoffman brain phantom containing three small uniform high-contrast ROIs and a large non-uniform low-contrast ROI. Our results show that the performances of LSD characterization are at least as good as those of the classical methods in terms of root mean square (RMS) error. For the three small tumor regions, LSD-ex allows a reduction in the estimation bias by up to 14%, resulting in a reduction in the RMS error of up to 8.5%, compared with the optimal classical estimation. For the large non-specific region, LSD using appropriate smoothing could intuitively and efficiently handle the resolution-variance tradeoff.
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Affiliation(s)
- F Ben Bouallègue
- Nuclear Medicine Department, Lapeyronie University Hospital, 371 avenue du Doyen Gaston Giraud, F-34295 Montpellier Cedex 5, France.
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Erlandsson K, Buvat I, Pretorius PH, Thomas BA, Hutton BF. A review of partial volume correction techniques for emission tomography and their applications in neurology, cardiology and oncology. Phys Med Biol 2012; 57:R119-59. [DOI: 10.1088/0031-9155/57/21/r119] [Citation(s) in RCA: 320] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Southekal S, McQuaid SJ, Kijewski MF, Moore SC. Evaluation of a method for projection-based tissue-activity estimation within small volumes of interest. Phys Med Biol 2012; 57:685-701. [PMID: 22241591 PMCID: PMC3741654 DOI: 10.1088/0031-9155/57/3/685] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A new method of compensating for tissue-fraction and count-spillover effects, which require tissue segmentation only within a small volume surrounding the primary lesion of interest, was evaluated for SPECT imaging. Tissue-activity concentration estimates are obtained by fitting the measured projection data to a statistical model of the segmented tissue projections. Multiple realizations of two simulated human-torso phantoms, each containing 20 spherical 'tumours', 1.6 cm in diameter, with tumour-to-background ratios of 8:1 and 4:1, were simulated. Estimates of tumour- and background-activity concentration values for homogeneous as well as inhomogeneous tissue activities were compared to the standard uptake value (SUV) metrics on the basis of accuracy and precision. For perfectly registered, high-contrast, superficial lesions in a homogeneous background without scatter, the method yielded accurate (<0.4% bias) and precise (<6.1%) recovery of the simulated activity values, significantly outperforming the SUV metrics. Tissue inhomogeneities, greater tumour depth and lower contrast ratios degraded precision (up to 11.7%), but the estimates remained almost unbiased. The method was comparable in accuracy but more precise than a well-established matrix inversion approach, even when errors in tumour size and position were introduced to simulate moderate inaccuracies in segmentation and image registration. Photon scatter in the object did not significantly affect the accuracy or precision of the estimates.
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Affiliation(s)
- Sudeepti Southekal
- Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St., Boston, MA 02115, USA.
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