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Bahl A, Segaud S, Xie Y, Shapey J, Bergholt MS, Vercauteren T. A comparative study of analytical models of diffuse reflectance in homogeneous biological tissues: Gelatin-based phantoms and Monte Carlo experiments. J Biophotonics 2024:e202300536. [PMID: 38616109 DOI: 10.1002/jbio.202300536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/12/2024] [Accepted: 03/06/2024] [Indexed: 04/16/2024]
Abstract
Information about tissue oxygen saturation (StO2) and other related important physiological parameters can be extracted from diffuse reflectance spectra measured through non-contact imaging. Three analytical optical reflectance models for homogeneous, semi-infinite, tissue have been proposed (Modified Beer-Lambert, Jacques 1999, Yudovsky 2009) but these have not been directly compared for tissue parameter extraction purposes. We compare these analytical models using Monte Carlo (MC) simulated diffuse reflectance spectra and controlled gelatin-based phantoms with measured diffuse reflectance spectra and known ground truth composition parameters. The Yudovsky model performed best against MC simulations and measured spectra of tissue phantoms in terms of goodness of fit and parameter extraction accuracy followed closely by Jacques' model. In this study, Yudovsky's model appeared most robust; however, our results demonstrated that both Yudovsky and Jacques models are suitable for modeling tissue that can be approximated as a single, homogeneous, semi-infinite slab.
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Affiliation(s)
- Anisha Bahl
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Silvere Segaud
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Yijing Xie
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Jonathan Shapey
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
- King's College Hospital, London, UK
| | - Mads S Bergholt
- Department of Craniofacial Development and Stem Cell Biology, King's College London, Guy's Tower, Great Maze Pond, London, UK
| | - Tom Vercauteren
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
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Doyle E, Dimmock MR, Lee KL, Thomas P, Bassed RB. Comparison of typical radiation doses and risks using an anthropomorphic 'bone fracture' phantom for commonly performed X-ray projections in a 5-year-old. J Med Radiat Sci 2024; 71:35-43. [PMID: 37602665 PMCID: PMC10920946 DOI: 10.1002/jmrs.717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 08/05/2023] [Indexed: 08/22/2023] Open
Abstract
INTRODUCTION Diagnostic reference levels (DRLs) are typical dose levels for medical imaging examinations for groups of standard-sized patients or standard phantoms for broadly defined types of equipment used as a tool to aid optimisation of protection for medical exposures. Currently, there are no paediatric DRLs for conventional radiography (i.e. general X-rays) published in Australia. The aim of this study was to establish typical radiation doses and risks that are representative of those delivered for commonly performed X-ray projections for a 5-year-old/20 kg child using a 5-year-old anthropomorphic 'bone fracture' phantom in three dedicated paediatric radiology departments in Victoria. METHODS A total of 20 projection images were acquired for a standard 5-year-old/20 kg phantom using digital radiography X-ray equipment. The air kerma-area product (KAP) measured at each centre by a KAP metre, which was calibrated to a national primary standard, was considered to represent the median value for that centre for each X-ray projection. Organ doses and effective dose were estimated using PCXMC software, and risks of radiation-induced cancer and radiation-induced death were calculated based on the BEIR VII report. RESULTS The typical doses for the individual X-ray projections ranged from 3 mGy•cm2 to 86 mGy•cm2 , whilst the effective doses ranged from 0.00004 to 0.07 mSv. The radiation risks were 'minimal' to 'negligible'. CONCLUSION The estimation of typical radiation doses and associated risks for a 5-year-old/20 kg phantom study provides reference values for guidance and is a first step in assisting optimisation at other institutions until national DRLs, based on patient data from the clinical setting, are published.
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Affiliation(s)
- Edel Doyle
- Department of Forensic MedicineMonash UniversityMelbourneVictoriaAustralia
| | - Matthew R Dimmock
- Department of Medical Imaging and Radiation SciencesMonash UniversityMelbourneVictoriaAustralia
- School of Allied Health ProfessionsKeele UniversityKeeleUK
| | - Kam L Lee
- Australian Radiation Protection and Nuclear Safety AgencyYallambieVictoriaAustralia
| | - Peter Thomas
- Australian Radiation Protection and Nuclear Safety AgencyYallambieVictoriaAustralia
| | - Richard B Bassed
- Department of Forensic MedicineMonash UniversityMelbourneVictoriaAustralia
- Victorian Institute of Forensic MedicineAcademic ProgramsMelbourneVictoriaAustralia
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Rabba JA, Jaafar HA, Suhaimi FM, Jafri MZM, Osman ND. A simplified low-cost phantom for image quality assessment of dental cone beam computed tomography unit. J Med Radiat Sci 2024; 71:78-84. [PMID: 37965811 PMCID: PMC10920926 DOI: 10.1002/jmrs.738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 10/24/2023] [Indexed: 11/16/2023] Open
Abstract
INTRODUCTION A standardised testing protocol for evaluation of a wide range of dental cone beam computed tomography (CBCT) performance and image quality (IQ) parameters is still limited and commercially available testing tool is unaffordable by some centres. This study aims to assess the performance of a low-cost fabricated phantom for image quality assessment (IQA) of digital CBCT unit. METHODS A customised polymethyl methacrylate (PMMA) cylindrical phantom was developed for performance evaluation of Planmeca ProMax 3D Mid digital dental CBCT unit. The fabricated phantom consists of four different layers for testing specific IQ parameters such as CT number accuracy and uniformity, noise and CT number linearity. The phantom was scanned using common scanning protocols in clinical routine (90.0 kV, 8.0 mA and 13.6 s). In region-of-interest (ROI) analysis, the mean CT numbers (in Hounsfield unit, HU) and noise for water and air were determined and compared with the reference values (0 HU for water and -1000 HU for air). For linearity test, the correlation between the measured HU of different inserts with their density was studied. RESULTS The average CT number were -994.1 HU and -2.4 HU, for air and water, respectively and the differences were within the recommended acceptable limit. The linearity test showed a strong positive correlation (R2 = 0.9693) between the measured HU and their densities. CONCLUSION The fabricated IQ phantom serves as a simple and affordable testing tool for digital dental CBCT imaging.
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Affiliation(s)
- James Anthony Rabba
- Advanced Medical and Dental InstituteUniversiti Sains MalaysiaPenangMalaysia
- Department of PhysicsFederal University LokojaLokojaNigeria
| | - Hanis Arina Jaafar
- Advanced Medical and Dental InstituteUniversiti Sains MalaysiaPenangMalaysia
| | | | | | - Noor Diyana Osman
- Advanced Medical and Dental InstituteUniversiti Sains MalaysiaPenangMalaysia
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Pálvölgyi L, Kesztyűs A, Shujaat S, Jacobs R, Nagy K. Creation of Dimicleft radiological cleft phantom skulls using reversed virtual planning technique. Dentomaxillofac Radiol 2023; 52:20230121. [PMID: 37395648 PMCID: PMC10552124 DOI: 10.1259/dmfr.20230121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 05/12/2023] [Accepted: 05/17/2023] [Indexed: 07/04/2023] Open
Abstract
OBJECTIVES The aim of this technical report was to develop customized pediatric phantoms for cone-beam computed tomography (CBCT)-related research in cleft patients. METHODS Six human pediatric skulls (age: 5-10 years) were recruited. A cone-beam computed tomography (CBCT) scan was taken for each skull, followed by virtual modeling through the process of segmentation. An artificial cleft was designed and printed to be applied onto the skull for the creation of an artificial cleft. The skulls were covered with non-radiopaque tape and immersed in melted Mix-D soft tissue equivalent material. The resulting phantoms covered with Mix-D were assessed radiologically by two expert radiologists. These phantoms were referred to as Dimicleft pediatric skull phantoms. RESULTS Dimicleft phantoms were able to appropriately mimic in vivo circumstances. No gaps existed between Mix-D and bony tissue. Virtual planning allowed the optimal designing of an artificial cleft onto the phantom. The artificially created cleft was suitable to determine the size, location, and extent of the cleft. CONCLUSIONS Dimicleft phantoms could act as a viable alternative to other commercially available options for assessing image quality and optimizing CBCT protocols in cleft patients for diagnostics and three-dimensional treatment planning.
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Affiliation(s)
- Laura Pálvölgyi
- Center for Facial Reconstruction, 1st Department of Paediatrics, Semmelweis University, Budapest, Hungary
| | - Artúr Kesztyűs
- Center for Facial Reconstruction, 1st Department of Paediatrics, Semmelweis University, Budapest, Hungary
| | | | | | - Krisztián Nagy
- Center for Facial Reconstruction, 1st Department of Paediatrics, Semmelweis University, Budapest, Hungary
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Rounds CC, Li C, Zhou W, Tichauer KM, Brankov JG. A cadaveric breast cancer tissue phantom for phase-contrast X-ray imaging applications. Animal Model Exp Med 2023; 6:427-432. [PMID: 37859563 PMCID: PMC10614119 DOI: 10.1002/ame2.12340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/19/2023] [Indexed: 10/21/2023] Open
Abstract
BACKGROUND As mammography X-ray imaging technologies advance and provide elevated contrast in soft tissues, a need has developed for reliable imaging phantoms for use in system design and component calibration. In advanced imaging modalities such as refraction-based methods, it is critical that developed phantoms capture the biological details seen in clinical precancerous and cancerous cases while minimizing artifacts that may be caused due to phantom production. This work presents the fabrication of a breast tissue imaging phantom from cadaveric breast tissue suitable for use in both transmission and refraction-enhanced imaging systems. METHODS Human cancer cell tumors were grown orthotopically in nude athymic mice and implanted into the fixed tissue while maintaining the native tumor/adipose tissue interface. RESULTS The resulting human-murine tissue hybrid phantom was mounted on a clear acrylic housing for absorption and refraction X-ray imaging. Digital breast tomosynthesis was also performed. CONCLUSION Both attenuation-based imaging and refraction-based imaging of the phantom are presented to confirm the suitability of this phantom's use in both imaging modalities.
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Affiliation(s)
- Cody C. Rounds
- Biomedical EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
- Medical Imaging Research CenterIllinois Institute of TechnologyChicagoIllinoisUSA
| | - Chengyue Li
- Biomedical EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
- Medical Imaging Research CenterIllinois Institute of TechnologyChicagoIllinoisUSA
| | - Wei Zhou
- Biomedical EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
- Medical Imaging Research CenterIllinois Institute of TechnologyChicagoIllinoisUSA
| | - Kenneth M. Tichauer
- Biomedical EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
- Medical Imaging Research CenterIllinois Institute of TechnologyChicagoIllinoisUSA
| | - Jovan G. Brankov
- Biomedical EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
- Medical Imaging Research CenterIllinois Institute of TechnologyChicagoIllinoisUSA
- Electrical and Computer EngineeringIllinois Institute of TechnologyChicagoIllinoisUSA
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van der Werf NR, van Gent M, Booij R, Bos D, van der Lugt A, Budde RPJ, Greuter MJW, van Straten M. Dose Reduction in Coronary Artery Calcium Scoring Using Mono-Energetic Images from Reduced Tube Voltage Dual-Source Photon-Counting CT Data: A Dynamic Phantom Study. Diagnostics (Basel) 2021; 11:2192. [PMID: 34943428 DOI: 10.3390/diagnostics11122192] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/17/2021] [Accepted: 11/21/2021] [Indexed: 12/23/2022] Open
Abstract
In order to assess coronary artery calcium (CAC) quantification reproducibility for photon-counting computed tomography (PCCT) at reduced tube potential, an anthropomorphic thorax phantom with low-, medium-, and high-density CAC inserts was scanned with PCCT (NAEOTOM Alpha, Siemens Healthineers) at two heart rates: 0 and 60–75 beats per minute (bpm). Five imaging protocols were used: 120 kVp standard dose (IQ level 16, reference), 90 kVp at standard (IQ level 16), 75% and 45% dose and tin-filtered 100 kVp at standard dose (IQ level 16). Each scan was repeated five times. Images were reconstructed using monoE reconstruction at 70 keV. For each heart rate, CAC values, quantified as Agatston scores, were compared with the reference, whereby deviations >10% were deemed clinically relevant. Reference protocol radiation dose (as volumetric CT dose index) was 4.06 mGy. Radiation dose was reduced by 27%, 44%, 67%, and 46% for the 90 kVp standard dose, 90 kVp 75% dose, 90 kVp 45% dose, and Sn100 standard dose protocol, respectively. For the low-density CAC, all reduced tube current protocols resulted in clinically relevant differences with the reference. For the medium- and high-density CAC, the implemented 90 kVp protocols and heart rates revealed no clinically relevant differences in Agatston score based on 95% confidence intervals. In conclusion, PCCT allows for reproducible Agatston scores at a reduced tube voltage of 90 kVp with radiation dose reductions up to 67% for medium- and high-density CAC.
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Zhou FL, McHugh DJ, Li Z, Gough JE, Williams GR, Parker GJM. Coaxial electrospun biomimetic copolymer fibres for application in diffusion magnetic resonance imaging. Bioinspir Biomim 2021; 16:046016. [PMID: 33706299 DOI: 10.1088/1748-3190/abedcf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Objective. The use of diffusion magnetic resonance imaging (dMRI) opens the door to characterizing brain microstructure because water diffusion is anisotropic in axonal fibres in brain white matter and is sensitive to tissue microstructural changes. As dMRI becomes more sophisticated and microstructurally informative, it has become increasingly important to use a reference object (usually called an imaging phantom) for validation of dMRI. This study aims to develop axon-mimicking physical phantoms from biocopolymers and assess their feasibility for validating dMRI measurements.Approach. We employed a simple and one-step method-coaxial electrospinning-to prepare axon-mimicking hollow microfibres from polycaprolactone-b-polyethylene glycol (PCL-b-PEG) and poly(D, L-lactide-co-glycolic) acid (PLGA), and used them as building elements to create axon-mimicking phantoms. Electrospinning was firstly conducted using two types of PCL-b-PEG and two types of PLGA with different molecular weights in various solvents, with different polymer concentrations, for determining their spinnability. Polymer/solvent concentration combinations with good fibre spinnability were used as the shell material in the following co-electrospinning process in which the polyethylene oxide polymer was used as the core material. Following the microstructural characterization of both electrospun and co-electrospun fibres using optical and electron microscopy, two prototype phantoms were constructed from co-electrospun anisotropic hollow microfibres after inserting them into water-filled test tubes.Main results. Hollow microfibres that mimic the axon microstructure were successfully prepared from the appropriate core and shell material combinations. dMRI measurements of two phantoms on a 7 tesla (T) pre-clinical scanner revealed that diffusivity and anisotropy measurements are in the range of brain white matter.Significance. This feasibility study showed that co-electrospun PCL-b-PEG and PLGA microfibre-based axon-mimicking phantoms could be used in the validation of dMRI methods which seek to characterize white matter microstructure.
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Affiliation(s)
- Feng-Lei Zhou
- Centre for Medical Image Computing, Department of Computer Science, University College London, London WC1V 6LJ, United Kingdom
- UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Damien J McHugh
- Quantitative Biomedical Imaging Laboratory, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Zhanxiong Li
- College of Textile and Clothing Engineering, Soochow University, Suzhou 215021, People's Republic of China
| | - Julie E Gough
- Department of Materials and Henry Royce Institute, The University of Manchester, Manchester M13 9PL, United Kingdom
| | - Gareth R Williams
- UCL School of Pharmacy, University College London, London WC1N 1AX, United Kingdom
| | - Geoff J M Parker
- Centre for Medical Image Computing, Department of Computer Science, University College London, London WC1V 6LJ, United Kingdom
- Bioxydyn Limited, Manchester, United Kingdom
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Dann T, Raphel J, Gammon ST, Mastrovich Z, Van Avermaete T, Jeffrey J, Adusumilli S, Leevy WM. Anatase Titanium Dioxide Imparts Photoluminescent Properties to PA2200 Commercial 3D Printing Material to Generate Complex Optical Imaging Phantoms. Materials (Basel) 2021; 14:1813. [PMID: 33917612 DOI: 10.3390/ma14071813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 01/06/2023]
Abstract
Selective laser sintering (SLS) is a prominent 3D printing modality that typically uses a polyamide (PA) powder as the substrate. One commercially available SLS material is known as PA2200, which is comprised of nylon 12 and titanium dioxide (TiO2) and is widely used to generate 3D-printed parts. Here, we report a unique optical photoluminescence (PL) characteristic of native, white PA2200, in which it yields a persistent, phosphorescence-type emission. An analysis of luminescence imaging data with emission measurements demonstrated that the anatase phase of the titanium dioxide additive is the source of the persistent PL properties. This characteristic of PA2200 enables advanced optical imaging applications, as demonstrated by luminescence imaging of an anatomical rat skeleton and a novel Derenzo-type phantom on a commercial image station. In summary, the light emission properties of PA2200 induced by the presence of anatase titanium dioxide open the door to a vast new array of complex optical applications, including the generation of imaging phantoms for training, calibration, and quality control.
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Little CD, Poduval RK, Caulfield R, Noimark S, Colchester RJ, Loder CD, Tiwari MK, Rakhit RD, Papakonstantinou I, Desjardins AE. Micron resolution, high-fidelity three-dimensional vascular optical imaging phantoms. J Biomed Opt 2019; 24:1-4. [PMID: 30770678 PMCID: PMC6498868 DOI: 10.1117/1.jbo.24.2.020502] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 01/08/2019] [Indexed: 05/13/2023]
Abstract
Microscopic and mesoscale optical imaging techniques allow for three-dimensional (3-D) imaging of biological tissue across millimeter-scale regions, and imaging phantom models are invaluable for system characterization and clinical training. Phantom models that replicate complex 3-D geometries with both structural and molecular contrast, with resolution and lateral dimensions equivalent to those of imaging techniques (<20 μm), have proven elusive. We present a method for fabricating phantom models using a combination of two-photon polymerization (2PP) to print scaffolds, and microinjection of tailored tissue-mimicking materials to simulate healthy and diseased tissue. We provide a first demonstration of the capabilities of this method with intravascular optical coherence tomography, an imaging technique widely used in clinical practice. We describe the design, fabrication, and validation of three types of phantom models: a first with subresolution wires (5- to 34-μm diameter) arranged circumferentially, a second with a vessel side-branch, and a third containing a lipid inclusion within a vessel. Silicone hybrid materials and lipids, microinjected within a resin framework created with 2PP, served as tissue-mimicking materials that provided realistic optical scattering and absorption. We demonstrate that optical phantom models made with 2PP and microinjected tissue-mimicking materials can simulate complex anatomy and pathology with exquisite detail.
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Affiliation(s)
- Callum D. Little
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- Royal Free Hospital, Department of Cardiology, London, United Kingdom
| | - Radhika K. Poduval
- University College London, Department of Electronic and Electrical Engineering, Photonic Innovations Lab, London, United Kingdom
- University College London, Department of Medical Physics and Bioengineering, London, United Kingdom
| | - Richard Caulfield
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- University College London, Department of Medical Physics and Bioengineering, London, United Kingdom
- University College London, Nanoengineered Systems Laboratory, UCL Mechanical Engineering, London, United Kingdom
| | - Sacha Noimark
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- University College London, Department of Medical Physics and Bioengineering, London, United Kingdom
| | - Richard J. Colchester
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- University College London, Department of Electronic and Electrical Engineering, Photonic Innovations Lab, London, United Kingdom
| | - Chris D. Loder
- Royal Free Hospital, Department of Cardiology, London, United Kingdom
| | - Manish K. Tiwari
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- University College London, Nanoengineered Systems Laboratory, UCL Mechanical Engineering, London, United Kingdom
| | - Roby D. Rakhit
- Royal Free Hospital, Department of Cardiology, London, United Kingdom
| | - Ioannis Papakonstantinou
- University College London, Department of Electronic and Electrical Engineering, Photonic Innovations Lab, London, United Kingdom
- Address all correspondence to Ioannis Papakonstantinou, E-mail: ; Adrien E. Desjardins, E-mail:
| | - Adrien E. Desjardins
- Wellcome Trust–EPSRC Centre for Interventional and Surgical Sciences, London, United Kingdom
- University College London, Department of Medical Physics and Bioengineering, London, United Kingdom
- Address all correspondence to Ioannis Papakonstantinou, E-mail: ; Adrien E. Desjardins, E-mail:
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Sevak S, Lurvey B, Woodfin AA, Hothem Z, Callahan RE, Robbins J, Ziegler K. Solid, Cystic, and Tubular: Novice Ultrasound Skills Training Using a Versatile, Affordable Practice Model. J Surg Educ 2018; 75:1403-1409. [PMID: 29650483 DOI: 10.1016/j.jsurg.2018.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 01/08/2018] [Accepted: 02/18/2018] [Indexed: 06/08/2023]
Abstract
OBJECTIVE In spite of the recognized benefits of ultrasound, many physicians have little experience with using ultrasound to perform procedures. Many medical schools and residency programs lack a formal ultrasound training curriculum. We describe an affordable ultrasound training curriculum and versatile, inexpensive practice model. DESIGN Participants underwent a didactic session to teach the theory required to perform ultrasound-guided procedures. Motor skills were taught using a practice model incorporating analogs of common anatomic and pathologic structures into an opacified gelatin substrate. SETTING The Marcia and Eugene Applebaum Simulation Learning Institute, Beaumont Hospital, Royal Oak, MI; a private nonprofit tertiary care hospital associated with the OUWB School of Medicine, Rochester, MI. PARTICIPANTS The model was tested in a cohort of 50 medical students and general surgery residents. RESULTS The gelatin model can be constructed for $1.03 per learner. The solid, cystic, and vascular structural analogs were readily identifiable on ultrasound and easily differentiated based on their echotextures. Eighty-four percent of participants successfully aspirated the cystic structure, 88% successfully biopsied a portion of the solid structure, and 76% successfully cannulated the tubular structure. Overall, 82% of participants achieved a passing score for the exercise based on a validated Objective Structured Assessment of Technical Skill instrument. There were no significant differences between the medical students and residents. CONCLUSION This model can be used to teach basic ultrasound skills such as aspiration, biopsy, and vessel cannulation, providing a foundation for the use of ultrasound in a broad range of clinical procedures, as well as providing practice opportunities for medical students and residents to gain increased ultrasound competency and confidence.
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Affiliation(s)
- Shruti Sevak
- Department of Surgery, Beaumont Health, Royal Oak, Michigan
| | - Benjamin Lurvey
- OUWB School of Medicine, Beaumont Health, Royal Oak, Michigan
| | | | - Zachary Hothem
- Department of Surgery, Beaumont Health, Royal Oak, Michigan
| | | | - James Robbins
- Department of Surgery, Beaumont Health, Royal Oak, Michigan; OUWB School of Medicine, Beaumont Health, Royal Oak, Michigan; Section of Trauma Surgery, Beaumont Health, Royal Oak, Michigan
| | - Kathryn Ziegler
- Department of Surgery, Beaumont Health, Royal Oak, Michigan; OUWB School of Medicine, Beaumont Health, Royal Oak, Michigan; Marcia and Eugene Applebaum Surgical Learning Institute, Beaumont Health, Royal Oak, Michigan.
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Kim H, Park CM, Kang CK, Yoon J, Chae KJ, Goo JM. Effect of CT Acquisition Parameters on Iodine Density Measurement at Dual-Layer Spectral CT. AJR Am J Roentgenol. 2018;211:748-754. [PMID: 30085834 DOI: 10.2214/ajr.17.19381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE We aimed to evaluate the effect of tube voltage, tube current-time product, and iterative reconstruction on iodine quantification using a dual-layer spectral CT scanner. MATERIALS AND METHODS Two mediastinal iodine phantoms, each containing six tubes of different iodine concentrations (0, 1, 2.5, 5, 10, and 20 mg I/mL; the two phantoms had tubes with contrast media diluted in water and in 10% amino acid solution, respectively), were inserted into an anthropomorphic chest phantom and scanned with varying acquisition parameters (120 and 140 kVp; 20, 40, 60, 80, 100, 150, and 200 mAs; and spectral reconstruction levels 0 and 6). Thereafter, iodine density was measured (in milligrams of iodine per milliliter) using a dedicated software program, and the effect of acquisition parameters on iodine density and on its relative measurement error (RME) was analyzed using a linear mixed-effects model. RESULTS Tube voltages (all, p < 0.001) and tube current-time products (p < 0.05, depending on the interaction terms for iodine density; p = 0.023 for RME) had statistically significant effects on iodine density and RME. However, the magnitude of their effects was minimal. That is, estimated differences between tube voltage settings ranged from 0 to 0.8 mg I/mL for iodine density and from 1.0% to 4.2% for RME. For tube current-time product, alteration of 100 mAs caused changes in iodine density and RME of approximately 0.1 mg I/mL and 0.6%, respectively. Spectral level was not an affecting factor for iodine quantification (p = 0.647 for iodine density and 0.813 for RME). CONCLUSION Iodine quantification using dual-layer spectral CT was feasible irrespective of CT acquisition parameters because their effects on iodine density and RME were minimal.
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Ceh J, Youd T, Mastrovich Z, Peterson C, Khan S, Sasser TA, Sander IM, Doney J, Turner C, Leevy WM. Bismuth Infusion of ABS Enables Additive Manufacturing of Complex Radiological Phantoms and Shielding Equipment. Sensors (Basel) 2017; 17:E459. [PMID: 28245589 DOI: 10.3390/s17030459] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/10/2017] [Accepted: 02/15/2017] [Indexed: 01/08/2023]
Abstract
Radiopacity is a critical property of materials that are used for a range of radiological applications, including the development of phantom devices that emulate the radiodensity of native tissues and the production of protective equipment for personnel handling radioactive materials. Three-dimensional (3D) printing is a fabrication platform that is well suited to creating complex anatomical replicas or custom labware to accomplish these radiological purposes. We created and tested multiple ABS (Acrylonitrile butadiene styrene) filaments infused with varied concentrations of bismuth (1.2–2.7 g/cm3), a radiopaque metal that is compatible with plastic infusion, to address the poor gamma radiation attenuation of many mainstream 3D printing materials. X-ray computed tomography (CT) experiments of these filaments indicated that a density of 1.2 g/cm3 of bismuth-infused ABS emulates bone radiopacity during X-ray CT imaging on preclinical and clinical scanners. ABS-bismuth filaments along with ABS were 3D printed to create an embedded human nasocranial anatomical phantom that mimicked radiological properties of native bone and soft tissue. Increasing the bismuth content in the filaments to 2.7 g/cm3 created a stable material that could attenuate 50% of 99mTechnetium gamma emission when printed with a 2.0 mm wall thickness. A shielded test tube rack was printed to attenuate source radiation as a protective measure for lab personnel. We demonstrated the utility of novel filaments to serve multiple radiological purposes, including the creation of anthropomorphic phantoms and safety labware, by tuning the level of radiation attenuation through material customization.
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