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Nasr B, Villa M, Benoit D, Visvikis D, Bert J. Monte Carlo Dosimetry Validation for X-Ray Guided Endovascular Procedures. Ann Vasc Surg 2024; 99:186-192. [PMID: 37717818 DOI: 10.1016/j.avsg.2023.07.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 07/23/2023] [Accepted: 07/25/2023] [Indexed: 09/19/2023]
Abstract
BACKGROUND Endovascular treatment is continuously gaining ground in vascular surgery procedures. However, current patient radiation dose estimation does not take into account the exact patient morphology and organs' composition. Monte Carlo (MC) simulation can accurately estimate the dose by recreating the irradiation process generated during X-ray-guided interventions. This study aimed to validate the MC simulation models by comparing simulated and measured dose distributions in endovascular aortic aneurysm repair (EVAR) procedures. METHODS We conducted a clinical study in patients treated for EVAR. Patient dose measurements were taken with passive dosimeters using Optically Stimulated Luminescence technology in 4 specific anatomical points on the skin: xiphoid process, pubic symphysis, right and left iliac crest. Dose measurements were compared to the corresponding simulated doses with the Geant4 Application for Emission Tomography (GATE) and GPU Geant4-based Monte Carlo Simulations (GGEMS) MC simulations softwares. The MC simulation took as input the computed tomography scan of the patient and the parameters of the imaging system (orientation angles, tube voltage, and aluminum filtration) and gives as output the three-dimensional (3D) dose map for each patient and angulation. RESULTS A good agreement with real doses was found for doses simulated by the MC GATE method (P < 0.0001; r = 0.97; 95% confidence interval [CI] [0.96-0.98]), as well as for doses simulated by the GGEMS method (P < 0.0001; r = 0.96; 95% CI [0.94-0.97]). The mean relative error for all measurements was 5 ± 5% in the MC GATE group and 6 ± 5% in the GGEMS group. Process execution on GGEMS (6 sec) was faster than the GATE MC simulation (5 hr). CONCLUSION Considering the current imaging settings, this study shows the potential of using the GATE and GGEMS MC simulations platforms to model the 3D dose distributions during EVAR procedures.
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Affiliation(s)
- Bahaa Nasr
- Univ Brest, INSERM, IMT-Atlantique, UMR 1011 LaTIM, Brest, France; CHU Cavale Blanche Brest, Vascular and Endovascular Surgery Department, Brest, France.
| | - Mateo Villa
- Univ Brest, INSERM, IMT-Atlantique, UMR 1011 LaTIM, Brest, France
| | - Didier Benoit
- Univ Brest, INSERM, IMT-Atlantique, UMR 1011 LaTIM, Brest, France
| | | | - Julien Bert
- Univ Brest, INSERM, IMT-Atlantique, UMR 1011 LaTIM, Brest, France
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Molinos C, Sasser T, Salmon P, Gsell W, Viertl D, Massey JC, Mińczuk K, Li J, Kundu BK, Berr S, Correcher C, Bahadur A, Attarwala AA, Stark S, Junge S, Himmelreich U, Prior JO, Laperre K, Van Wyk S, Heidenreich M. Low-Dose Imaging in a New Preclinical Total-Body PET/CT Scanner. Front Med (Lausanne) 2019; 6:88. [PMID: 31131277 PMCID: PMC6509903 DOI: 10.3389/fmed.2019.00088] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Accepted: 04/09/2019] [Indexed: 12/17/2022] Open
Abstract
Ionizing radiation constitutes a health risk to imaging scientists and study animals. Both PET and CT produce ionizing radiation. CT doses in pre-clinical in vivo imaging typically range from 50 to 1,000 mGy and biological effects in mice at this dose range have been previously described. [18F]FDG body doses in mice have been estimated to be in the range of 100 mGy for [18F]FDG. Yearly, the average whole body doses due to handling of activity by PET technologists are reported to be 3–8 mSv. A preclinical PET/CT system is presented with design features which make it suitable for small animal low-dose imaging. The CT subsystem uses a X-source power that is optimized for small animal imaging. The system design incorporates a spatial beam shaper coupled with a highly sensitive flat-panel detector and very fast acquisition (<10 s) which allows for whole body scans with doses as low as 3 mGy. The mouse total-body PET subsystem uses a detector architecture based on continuous crystals, coupled to SiPM arrays and a readout based in rows and columns. The PET field of view is 150 mm axial and 80 mm transaxial. The high solid-angle coverage of the sample and the use of continuous crystals achieve a sensitivity of 9% (NEMA) that can be leveraged for use of low tracer doses and/or performing rapid scans. The low-dose imaging capabilities of the total-body PET subsystem were tested with NEMA phantoms, in tumor models, a mouse bone metabolism scan and a rat heart dynamic scan. The CT imaging capabilities were tested in mice and in a low contrast phantom. The PET low-dose phantom and animal experiments provide evidence that image quality suitable for preclinical PET studies is achieved. Furthermore, CT image contrast using low dose scan settings was suitable as a reference for PET scans. Total-body mouse PET/CT studies could be completed with total doses of <10 mGy.
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Affiliation(s)
- Cesar Molinos
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | - Todd Sasser
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | - Phil Salmon
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | | | - David Viertl
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
| | - James C Massey
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | - Krzysztof Mińczuk
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | - Jie Li
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | - Bijoy K Kundu
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | - Stuart Berr
- Department of Radiology and Medical Imaging, University of Virginia, Charlottesville, VA, United States
| | | | - Ali Bahadur
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | | | - Simon Stark
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | - Sven Junge
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
| | | | - John O Prior
- Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, Lausanne, Switzerland
| | - Kjell Laperre
- Bruker BioSpin, Preclinical Imaging, Ettlingen, Germany
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Mannheim JG, Kara F, Doorduin J, Fuchs K, Reischl G, Liang S, Verhoye M, Gremse F, Mezzanotte L, Huisman MC. Standardization of Small Animal Imaging-Current Status and Future Prospects. Mol Imaging Biol 2019; 20:716-731. [PMID: 28971332 DOI: 10.1007/s11307-017-1126-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The benefit of small animal imaging is directly linked to the validity and reliability of the collected data. If the data (regardless of the modality used) are not reproducible and/or reliable, then the outcome of the data is rather questionable. Therefore, standardization of the use of small animal imaging equipment, as well as of animal handling in general, is of paramount importance. In a recent paper, guidance for efficient small animal imaging quality control was offered and discussed, among others, the use of phantoms in setting up a quality control program (Osborne et al. 2016). The same phantoms can be used to standardize image quality parameters for multi-center studies or multi-scanners within center studies. In animal experiments, the additional complexity due to animal handling needs to be addressed to ensure standardized imaging procedures. In this review, we will address the current status of standardization in preclinical imaging, as well as potential benefits from increased levels of standardization.
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Affiliation(s)
- Julia G Mannheim
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany.
| | - Firat Kara
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
| | - Janine Doorduin
- Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Kerstin Fuchs
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany
| | - Gerald Reischl
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Roentgenweg 13, 72076, Tuebingen, Germany
| | - Sayuan Liang
- Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium
| | | | - Felix Gremse
- Institute for Experimental Molecular Imaging, RWTH Aachen University Clinic, Aachen, Germany
| | - Laura Mezzanotte
- Optical Molecular Imaging, Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marc C Huisman
- Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands
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Mendez C, Colpo N, Duzenli C, Atwal P, Gill B. Technical Note: Development of a phantom for dosimetric comparison of murine micro-CT protocols with optically stimulated luminescent dosimeters. Med Phys 2018; 45:3974-3979. [PMID: 29971794 DOI: 10.1002/mp.13079] [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: 12/11/2017] [Revised: 06/04/2018] [Accepted: 06/27/2018] [Indexed: 11/08/2022] Open
Abstract
PURPOSE This work aims to evaluate the utility and accuracy of a mouse-like phantom and optically stimulated luminescent dosimeters (OSLDs) in measuring dose delivered to the body and lung of mice undergoing micro-CT imaging. METHODS A phantom with two cavities for NanoDot OSLDs (Landauer, Inc., Greenwood, IL) was designed and constructed using acrylic to model the mouse body and polyurethane foam to obtain an approximate lung tissue dose. The OSLD dose was compared to ion chamber measurements for the same imaging protocols delivered by a Siemens Inveon micro-CT (Siemens Medical Solutions USA, Inc., Hoffman Estates, IL, USA). A whole body scan, using 80 kV, 0.5 mA and 0.5 mm of aluminum filter, was used to compare results to previously published data. Additionally, dose was measured for the whole body scan without the aluminum filter and two chest protocols (full and half rotation). RESULTS OSLD dose results agree with chamber measurements within 3%. Average OSLD measurements for the whole body scan without filter were 10.7 ± 0.7 cGy in the abdomen and 11.2 ± 0.7 cGy in the lung. For the full rotation chest protocol, the average dose measured in the lung was 65.8 ± 4.3 cGy and 60.2 ± 3.9 cGy in the abdomen. Average doses were 41.1 ± 2.7 cGy in the lung and 38.2 ± 2.5 cGy in the abdomen for the half rotation chest protocol. The OSLD measurements showed a coefficient of variation under 1.4%. A maximum rotational geometry under-response of 0.86% with respect to exposure at normal incidence to the OSLD was measured. CONCLUSIONS The doses measured were found to be comparable to other studies for the scanner configuration and protocols chosen. The phantom built for this study was found to give reproducible dose measurements with 4% uncertainty. In this way, a robust and convenient method is established for future dose assessment of micro-CT protocols and interinstitutional comparisons.
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Affiliation(s)
- Claudia Mendez
- Department of Medical Physics, British Columbia Cancer Agency, 600 West 10th Avenue, Vancouver, British Columbia, V5Z 4E6, Canada
| | - Nadine Colpo
- Molecular Oncology, British Columbia Cancer Research Centre, 675 West 10th Avenue, Vancouver, British Columbia, V5Z 1L3, Canada
| | - Cheryl Duzenli
- Department of Medical Physics, British Columbia Cancer Agency, 600 West 10th Avenue, Vancouver, British Columbia, V5Z 4E6, Canada
- Department of Physics and Astronomy, University of British Columbia, 2329 West Mall, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Parmveer Atwal
- Department of Medical Physics, British Columbia Cancer Agency, 32900 Marshall Road, Abbotsford, British Columbia, V2S 0C2, Canada
| | - Brad Gill
- Department of Medical Physics, British Columbia Cancer Agency, 600 West 10th Avenue, Vancouver, British Columbia, V5Z 4E6, Canada
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Meganck JA, Liu B. Dosimetry in Micro-computed Tomography: a Review of the Measurement Methods, Impacts, and Characterization of the Quantum GX Imaging System. Mol Imaging Biol 2018; 19:499-511. [PMID: 27957647 PMCID: PMC5498628 DOI: 10.1007/s11307-016-1026-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Purpose X-ray micro-computed tomography (μCT) is a widely used imaging modality in preclinical research with applications in many areas including orthopedics, pulmonology, oncology, cardiology, and infectious disease. X-rays are a form of ionizing radiation and, therefore, can potentially induce damage and cause detrimental effects. Previous reviews have touched on these effects but have not comprehensively covered the possible implications on study results. Furthermore, interpreting data across these studies is difficult because there is no widely accepted dose characterization methodology for preclinical μCT. The purpose of this paper is to ensure in vivo μCT studies can be properly designed and the data can be appropriately interpreted. Procedures Studies from the scientific literature that investigate the biological effects of radiation doses relevant to μCT were reviewed. The different dose measurement methodologies used in the peer-reviewed literature were also reviewed. The CT dose index 100 (CTDI100) was then measured on the Quantum GX μCT instrument. A low contrast phantom, a hydroxyapatite phantom, and a mouse were also imaged to provide examples of how the dose can affect image quality. Results Data in the scientific literature indicate that scenarios exist where radiation doses used in μCT imaging are high enough to potentially bias experimental results. The significance of this effect may relate to the study outcome and tissue being imaged. CTDI100 is a reasonable metric to use for dose characterization in μCT. Dose rates in the Quantum GX vary based on the amount of material in the beam path and are a function of X-ray tube voltage. The CTDI100 in air for a Quantum GX can be as low as 5.1 mGy for a 50 kVp scan and 9.9 mGy for a 90 kVp scan. This dose is low enough to visualize bone both in a mouse image and in a hydroxyapatite phantom, but applications requiring higher resolution in a mouse or less noise in a low-contrast phantom benefit from longer scan times with increased dose. Conclusions Dose management should be considered when designing μCT studies. Dose rates in the Quantum GX are compatible with longitudinal μCT imaging.
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Affiliation(s)
- Jeffrey A Meganck
- Research and Development, Life Sciences Technology, PerkinElmer, 68 Elm Street, Hopkinton, MA, 01748, USA.
| | - Bob Liu
- Department of Radiology, Massachusetts General Hospital, Boston, MA, USA
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Balaguru D, Rodriguez M, Leon S, Wagner LK, Beasley CW, Sultzer A, Numan MT. Comparison of skin dose measurement using nanoDot ® dosimeter and machine readings of radiation dose during cardiac catheterization in children. Ann Pediatr Cardiol 2018; 11:12-16. [PMID: 29440825 PMCID: PMC5803971 DOI: 10.4103/apc.apc_86_17] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Objectives Direct measurement of skin dose of radiation for children using optically stimulated luminescence (OSL) technology using nanoDot® (Landauer, Glenwood, IL, USA). Background Radiation dose is estimated as cumulative air kerma (AK) and dosearea product based on standards established for adult size patients. Body size of pediatric patients who undergo cardiac catheterization for congenital heart disease vary widely from newborn to adolescence. Direct, skindose measurement applying OSL technology may eliminate errors in the estimate. Materials and Methods The nanoDot® (1 cm × 1 cm × flat plastic cassette) is applied to patient's skin using adhesive tape during cardiac catheterization and radiation skin doses were read within 24 hrs. nanoDot® values were compared to the currently available cumulative AK values estimated and displayed on fluoroscopy monitor. Results A total of 12 children were studied, aged 4 months to 18 years (median 1.1 years) and weight range 5.3-86 kg (median 8.4 kg). nanoDot® readings ranged from 2.58 mGy to 424.8 mGy (median 84.1 mGy). Cumulative AK ranged from 16.2 mGy to 571.2 mGy (median 171.1 mGy). Linear correlation was noted between nanoDot® values and AK values (R2 = 0.88, R = 0.94). nanoDot® readings were approximately 65% of the estimated cumulative AK estimated using the International Electrotechnical Commission standards. Conclusions Application of OSL technology using nanoDot® provides an alternative to directly measure fluoroscopic skin dose in children during cardiac catheterization. Our data show that the actual skin dose for children is approximately one-third lower than the AK estimated using international standards for adult size patients.
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Affiliation(s)
- Duraisamy Balaguru
- Division of Pediatric Cardiology, University of Texas Houston McGovern Medical School, Glenwood, IL, USA
| | | | - Stephanie Leon
- Department of Diagnostic and Interventional Imaging, University of Texas Houston School of Medicine, Houston, TX, USA
| | - Louis K Wagner
- Department of Diagnostic and Interventional Imaging, University of Texas Houston School of Medicine, Houston, TX, USA
| | - Charles W Beasley
- Department of Diagnostic and Interventional Imaging, University of Texas Houston School of Medicine, Houston, TX, USA
| | - Andrew Sultzer
- Division of Pediatric Cardiology, University of Texas Houston McGovern Medical School, Glenwood, IL, USA
| | - Mohammed T Numan
- Division of Pediatric Cardiology, University of Texas Houston McGovern Medical School, Glenwood, IL, USA
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Zeller-Plumhoff B, Roose T, Clough GF, Schneider P. Image-based modelling of skeletal muscle oxygenation. J R Soc Interface 2017; 14:rsif.2016.0992. [PMID: 28202595 DOI: 10.1098/rsif.2016.0992] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 01/25/2017] [Indexed: 12/12/2022] Open
Abstract
The supply of oxygen in sufficient quantity is vital for the correct functioning of all organs in the human body, in particular for skeletal muscle during exercise. Disease is often associated with both an inhibition of the microvascular supply capability and is thought to relate to changes in the structure of blood vessel networks. Different methods exist to investigate the influence of the microvascular structure on tissue oxygenation, varying over a range of application areas, i.e. biological in vivo and in vitro experiments, imaging and mathematical modelling. Ideally, all of these methods should be combined within the same framework in order to fully understand the processes involved. This review discusses the mathematical models of skeletal muscle oxygenation currently available that are based upon images taken of the muscle microvasculature in vivo and ex vivo Imaging systems suitable for capturing the blood vessel networks are discussed and respective contrasting methods presented. The review further informs the association between anatomical characteristics in health and disease. With this review we give the reader a tool to understand and establish the workflow of developing an image-based model of skeletal muscle oxygenation. Finally, we give an outlook for improvements needed for measurements and imaging techniques to adequately investigate the microvascular capability for oxygen exchange.
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Affiliation(s)
- B Zeller-Plumhoff
- Helmholtz-Zentrum für Material- und Küstenforschung, Geesthacht, Germany .,Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - T Roose
- Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
| | - G F Clough
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - P Schneider
- Bioengineering Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
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Feasibility and Initial Performance of Simultaneous SPECT-CT Imaging Using a Commercial Multi-Modality Preclinical Imaging System. INTERNATIONAL JOURNAL OF MOLECULAR IMAGING 2015; 2015:134768. [PMID: 26146568 PMCID: PMC4469763 DOI: 10.1155/2015/134768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/11/2015] [Accepted: 04/16/2015] [Indexed: 11/18/2022]
Abstract
Multi-modality imaging provides coregistered PET-CT and SPECT-CT images; however such multi-modality workflows usually consist of sequential scans from the individual imaging components for each modality. This typical workflow may result in long scan times limiting throughput of the imaging system. Conversely, acquiring multi-modality data simultaneously may improve correlation and registration of images, improve temporal alignment of the acquired data, increase imaging throughput, and benefit the scanned subject by minimizing time under anesthetic. In this work, we demonstrate the feasibility and procedure for modifying a commercially available preclinical SPECT-CT platform to enable simultaneous SPECT-CT acquisition. We also evaluate the performance of simultaneous SPECT-CT tomographic imaging with this modified system. Performance was accessed using a (57)Co source and image quality was evaluated with (99m)Tc phantoms in a series of simultaneous SPECT-CT scans.
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Starosolski Z, Villamizar CA, Rendon D, Paldino MJ, Milewicz DM, Ghaghada KB, Annapragada AV. Ultra High-Resolution In vivo Computed Tomography Imaging of Mouse Cerebrovasculature Using a Long Circulating Blood Pool Contrast Agent. Sci Rep 2015; 5:10178. [PMID: 25985192 PMCID: PMC4650815 DOI: 10.1038/srep10178] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 04/01/2015] [Indexed: 12/21/2022] Open
Abstract
Abnormalities in the cerebrovascular system play a central role in many neurologic diseases. The on-going expansion of rodent models of human cerebrovascular diseases and the need to use these models to understand disease progression and treatment has amplified the need for reproducible non-invasive imaging methods for high-resolution visualization of the complete cerebral vasculature. In this study, we present methods for in vivo high-resolution (19 μm isotropic) computed tomography imaging of complete mouse brain vasculature. This technique enabled 3D visualization of large cerebrovascular networks, including the Circle of Willis. Blood vessels as small as 40 μm were clearly delineated. ACTA2 mutations in humans cause cerebrovascular defects, including abnormally straightened arteries and a moyamoya-like arteriopathy characterized by bilateral narrowing of the internal carotid artery and stenosis of many large arteries. In vivo imaging studies performed in a mouse model of Acta2 mutations demonstrated the utility of this method for studying vascular morphometric changes that are practically impossible to identify using current histological methods. Specifically, the technique demonstrated changes in the width of the Circle of Willis, straightening of cerebral arteries and arterial stenoses. We believe the use of imaging methods described here will contribute substantially to the study of rodent cerebrovasculature.
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Affiliation(s)
- Zbigniew Starosolski
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Carlos A Villamizar
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX
| | - David Rendon
- Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Michael J Paldino
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Dianna M Milewicz
- Department of Internal Medicine, University of Texas Health Science Center at Houston, Houston, TX
| | - Ketan B Ghaghada
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
| | - Ananth V Annapragada
- 1] Edward B. Singleton Department of Pediatric Radiology, Texas Children's Hospital, Houston TX [2] Department of Radiology, Baylor College of Medicine, Houston, TX
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Vrigneaud JM, Courteau A, Ranouil J, Morgand L, Raguin O, Walker P, Oudot A, Collin B, Brunotte F. Application of the optically stimulated luminescence (OSL) technique for mouse dosimetry in micro-CT imaging. Med Phys 2013; 40:122102. [PMID: 24320529 DOI: 10.1118/1.4829499] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
PURPOSE Micro-CT is considered to be a powerful tool to investigate various models of disease on anesthetized animals. In longitudinal studies, the radiation dose delivered by the micro-CT to the same animal is a major concern as it could potentially induce spurious effects in experimental results. Optically stimulated luminescence dosimeters (OSLDs) are a relatively new kind of detector used in radiation dosimetry for medical applications. The aim of this work was to assess the dose delivered by the CT component of a micro-SPECT (single-photon emission computed tomography)∕CT camera during a typical whole-body mouse study, using commercially available OSLDs based on Al2O3:C crystals. METHODS CTDI (computed tomography dose index) was measured in micro-CT with a properly calibrated pencil ionization chamber using a rat-like phantom (60 mm in diameter) and a mouse-like phantom (30 mm in diameter). OSLDs were checked for reproducibility and linearity in the range of doses delivered by the micro-CT. Dose measurements obtained with OSLDs were compared to those of the ionization chamber to correct for the radiation quality dependence of OSLDs in the low-kV range. Doses to tissue were then investigated in phantoms and cadavers. A 30 mm diameter phantom, specifically designed to insert OSLDs, was used to assess radiation dose over a typical whole-body mouse imaging study. Eighteen healthy female BALB∕c mice weighing 27.1 ± 0.8 g (1 SD) were euthanized for small animal measurements. OLSDs were placed externally or implanted internally in nine different locations by an experienced animal technician. Five commonly used micro-CT protocols were investigated. RESULTS CTDI measurements were between 78.0 ± 2.1 and 110.7 ± 3.0 mGy for the rat-like phantom and between 169.3 ± 4.6 and 203.6 ± 5.5 mGy for the mouse-like phantom. On average, the displayed CTDI at the operator console was underestimated by 1.19 for the rat-like phantom and 2.36 for the mouse-like phantom. OSLDs exhibited a reproducibility of 2.4% and good linearity was found between 60 and 450 mGy. The energy scaling factor was calculated to be between 1.80 ± 0.16 and 1.86 ± 0.16, depending on protocol used. In phantoms, mean doses to tissue over a whole-body CT examination were ranging from 186.4 ± 7.6 to 234.9 ± 7.1 mGy. In mice, mean doses to tissue in the mouse trunk (thorax, abdomen, pelvis, and flanks) were between 213.0 ± 17.0 and 251.2 ± 13.4 mGy. Skin doses (3 OSLDs) were much higher with average doses between 350.6 ± 25.3 and 432.5 ± 34.1 mGy. The dose delivered during a topogram was found to be below 10 mGy. Use of the multimouse bed of the system gave a significantly 20%-40% lower dose per animal (p < 0.05). CONCLUSIONS Absorbed doses in micro-CT were found to be relatively high. In micro-SPECT∕CT imaging, the micro-CT unit is mainly used to produce a localization frame. As a result, users should pay attention to adjustable CT parameters so as to minimize the radiation dose and avoid any adverse radiation effects which may interfere with biological parameters studied.
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Affiliation(s)
- Jean-Marc Vrigneaud
- Department of Nuclear Medicine, Centre Georges-François Leclerc, 1 rue Professeur Marion, Dijon 21079 Cedex, France
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Lee S, Gregor J, Osborne D. Development and Validation of a Complete GATE Model of the Siemens Inveon Trimodal Imaging Platform. Mol Imaging 2013. [DOI: 10.2310/7290.2013.00058] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Sanghyeb Lee
- From the Department of Electrical Engineering and Computer Science and Graduate School of Medicine, University of Tennessee, Knoxville, TN
| | - Jens Gregor
- From the Department of Electrical Engineering and Computer Science and Graduate School of Medicine, University of Tennessee, Knoxville, TN
| | - Dustin Osborne
- From the Department of Electrical Engineering and Computer Science and Graduate School of Medicine, University of Tennessee, Knoxville, TN
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Lalwani K, Giddabasappa A, Li D, Olson P, Simmons B, Shojaei F, Arsdale TV, Christensen J, Jackson-Fisher A, Wong A, Lappin PB, Eswaraka J. Contrast agents for quantitative microCT of lung tumors in mice. Comp Med 2013; 63:482-490. [PMID: 24326223 PMCID: PMC3866987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 03/26/2013] [Accepted: 05/28/2013] [Indexed: 06/03/2023]
Abstract
The identification and quantitative evaluation of lung tumors in mouse models is challenging and an unmet need in preclinical arena. In this study, we developed a noninvasive contrast-enhanced microCT (μCT) method to longitudinally evaluate and quantitate lung tumors in mice. Commercially available μCT contrast agents were compared to determine the optimal agent for visualization of thoracic blood vessels and lung tumors in naïve mice and in non-small-cell lung cancer models. Compared with the saline control, iopamidol and iodinated lipid agents provided only marginal increases in contrast resolution. The inorganic nanoparticulate agent provided the best contrast and visualization of thoracic vascular structures; the density contrast was highest at 15 min after injection and was stable for more than 4 h. Differential contrast of the tumors, vascular structures, and thoracic air space by the nanoparticulate agent enabled identification of tumor margins and accurate quantification. μCT data correlated closely with traditional histologic measurements (Pearson correlation coefficient, 0.995). Treatment of ELM4-ALK mice with crizotinib yielded 65% reduction in tumor size and thus demonstrated the utility of quantitative μCT in longitudinal preclinical trials. Overall and among the 3 agents we tested, the inorganic nanoparticulate product was the best commercially available contrast agent for visualization of thoracic blood vessels and lung tumors. Contrast-enhanced μCT imaging is an excellent noninvasive method for longitudinal evaluation during preclinical lung tumor studies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Anthony Wong
- Drug Safety Research and Development, Pfizer, San Diego, California
| | - Patrick B Lappin
- Drug Safety Research and Development, Pfizer, San Diego, California
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