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https://www.readbyqxmd.com/read/29786862/experimental-fluence-modulated-proton-computed-tomography-by-pencil-beam-scanning
#1
George Dedes, Robert P Johnson, Mark Pankuch, Nick Detrich, Willemijn M A Pols, Simon Rit, Reinhard W Schulte, Katia Parodi, Guillaume Landry
PURPOSE: This experimental study is aimed at demonstrating, using a simple cylindrical water phantom, the feasibility of fluence modulated proton computed tomography (FMpCT) by pencil beam scanning (PBS) proton computed tomography (pCT). METHODS: The phase II pCT prototype of the Loma Linda U. and U. C. Santa Cruz was operated using the PBS beam line of the Northwestern Medicine Chicago Proton Center. A 20x10 grid of 1.37 cm full width half maximum pencil beams (PB) equally spaced by 1 cm was used to acquire 45 projections in step and shoot mode...
May 22, 2018: Medical Physics
https://www.readbyqxmd.com/read/29786775/stormram-4-an-mr-safe-robotic-system-for-breast-biopsy
#2
Vincent Groenhuis, Françoise J Siepel, Jeroen Veltman, Jordy K van Zandwijk, Stefano Stramigioli
Suspicious lesions in the breast that are only visible on magnetic resonance imaging (MRI) need to be biopsied under MR guidance with high accuracy and efficiency for accurate diagnosis. The aim of this study is to present a novel robotic system, the Stormram 4, and to perform preclinical tests in an MRI environment. Excluding racks and needle, its dimensions are 72 × 51 × 40 mm. The Stormram 4 is driven by two linear and two curved pneumatic stepper motors. The linear motor is capable of exerting 63 N of force at a pressure of 0...
May 21, 2018: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/29786774/computational-fluid-dynamics-modeling-of-the-human-pulmonary-arteries-with-experimental-validation
#3
Alifer D Bordones, Matthew Leroux, Vitaly O Kheyfets, Yu-An Wu, Chia-Yuan Chen, Ender A Finol
Pulmonary hypertension (PH) is a chronic progressive disease characterized by elevated pulmonary arterial pressure, caused by an increase in pulmonary arterial impedance. Computational fluid dynamics (CFD) can be used to identify metrics representative of the stage of PH disease. However, experimental validation of CFD models is often not pursued due to the geometric complexity of the model or uncertainties in the reproduction of the required flow conditions. The goal of this work is to validate experimentally a CFD model of a pulmonary artery phantom using a particle image velocimetry (PIV) technique...
May 21, 2018: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/29785839/optimization-of-a-secondary-voi-protocol-for-lung-imaging-in-a-clinical-ct-scanner
#4
Thomas C Larsen, Vissagan Gopalakrishnan, Jianhua Yao, Catherine P Nguyen, Marcus Y Chen, Joel Moss, Han Wen
We present a solution to meet an unmet clinical need of an in-situ "close look" at a pulmonary nodule or at the margins of a pulmonary cyst revealed by a primary (screening) chest CT while the patient is still in the scanner. We first evaluated options available on current whole-body CT scanners for high resolution screening scans, including ROI reconstruction of the primary scan data and HRCT, but found them to have insufficient SNR in lung tissue or discontinuous slice coverage. Within the capabilities of current clinical CT systems, we opted for the solution of a secondary, volume-of-interest (VOI) protocol where the radiation dose is focused into a short-beam axial scan at the z position of interest, combined with a small-FOV reconstruction at the xy position of interest...
May 21, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29785834/development-of-a-robust-mri-fiducial-system-for-automated-fusion-of-mr-us-abdominal-images
#5
Christopher P Favazza, Krzysztof R Gorny, Matthew R Callstrom, Anil N Kurup, Michael Washburn, Pamela S Trester, Charles L Fowler, Nicholas J Hangiandreou
We present the development of a two-component magnetic resonance (MR) fiducial system, that is, a fiducial marker device combined with an auto-segmentation algorithm, designed to be paired with existing ultrasound probe tracking and image fusion technology to automatically fuse MR and ultrasound (US) images. The fiducial device consisted of four ~6.4 mL cylindrical wells filled with 1 g/L copper sulfate solution. The algorithm was designed to automatically segment the device in clinical abdominal MR images...
May 21, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29785725/density-scaling-of-phantom-materials-for-a-3d-dose-verification-system
#6
Kensuke Tani, Yukio Fujita, Akihisa Wakita, Ryohei Miyasaka, Ryuzo Uehara, Takumi Kodama, Yuya Suzuki, Ako Aikawa, Norifumi Mizuno, Jiro Kawamori, Hidetoshi Saitoh
In this study, the optimum density scaling factors of phantom materials for a commercially available three-dimensional (3D) dose verification system (Delta4) were investigated in order to improve the accuracy of the calculated dose distributions in the phantom materials. At field sizes of 10 × 10 and 5 × 5 cm2 with the same geometry, tissue-phantom ratios (TPRs) in water, polymethyl methacrylate (PMMA), and Plastic Water Diagnostic Therapy (PWDT) were measured, and TPRs in various density scaling factors of water were calculated by Monte Carlo simulation, Adaptive Convolve (AdC, Pinnacle3 ), Collapsed Cone Convolution (CCC, RayStation), and AcurosXB (AXB, Eclipse)...
May 21, 2018: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/29785411/low-dose-ct-perfusion-of-the-liver-using-reconstruction-of-difference
#7
Saeed Seyyedi, Eleni Liapi, Tobias Lasser, Robert Ivkov, Rajeev Hatwar, J Webster Stayman
Liver CT perfusion (CTP) is used in the detection, staging, and treatment response analysis of hepatic diseases. Unfortunately, CTP radiation exposures is significant, limiting more widespread use. Traditional CTP data processing reconstructs individual temporal samples, ignoring a large amount of shared anatomical information between temporal samples, suggesting opportunities for improved data processing. We adopt a prior-image-based reconstruction approach called Reconstruction of Difference (RoD) to enable low-exposure CTP acquisition...
May 2018: IEEE Transactions on Radiation and Plasma Medical Sciences
https://www.readbyqxmd.com/read/29784460/review-of-real-time-3-dimensional-image-guided-radiation-therapy-on-standard-equipped-cancer-radiation-therapy-systems-are-we-at-the-tipping-point-for-the-era-of-real-time-radiation-therapy
#8
Paul J Keall, Doan Trang Nguyen, Ricky O'Brien, Pengpeng Zhang, Laura Happersett, Jenny Bertholet, Per R Poulsen
PURPOSE: To review real-time 3-dimensional (3D) image guided radiation therapy (IGRT) on standard-equipped cancer radiation therapy systems, focusing on clinically implemented solutions. METHODS AND MATERIALS: Three groups in 3 continents have clinically implemented novel real-time 3D IGRT solutions on standard-equipped linear accelerators. These technologies encompass kilovoltage, combined megavoltage-kilovoltage, and combined kilovoltage-optical imaging. The cancer sites treated span pelvic and abdominal tumors for which respiratory motion is present...
April 14, 2018: International Journal of Radiation Oncology, Biology, Physics
https://www.readbyqxmd.com/read/29784436/a-3-d-region-growing-motion-tracking-method-for-ultrasound-elasticity-imaging
#9
Yuqi Wang, Jingfeng Jiang, Timothy J Hall
A 3-D region-growing motion-tracking (RGMT) method for ultrasound elasticity imaging is described. This 3-D RGMT method first estimates the displacements at a sparse subset of points, called seeds; uses an objective measure to determine, among those seeds, which displacement estimates to trust; and then performs RGMT in three dimensions to estimate displacements for the remaining points in the field. During the growing process in three dimensions, the displacement estimate at one grid point is employed to guide the displacement estimation of its neighboring points using a 3-D small search region...
May 18, 2018: Ultrasound in Medicine & Biology
https://www.readbyqxmd.com/read/29782657/phantom-clinical-and-texture-indices-evaluation-and-optimization-of-a-penalized-likelihood-image-reconstruction-method-q-clear-on-a-bgo-pet-ct-scanner
#10
Gabriel Reynés-Llompart, Cristina Gámez-Cenzano, José Luís Vercher-Conejero, Aida Sabaté-Llobera, Nahúm Calvo-Malvar, Josep M Martí-Climent
INTRODUCTION: The aim of this study was to evaluate the behavior of a penalized-likelihood image reconstruction method (Q.Clear) under different count statistics and lesion-to-background ratios (LBR) on a BGO scanner, in order to obtain an optimum penalization factor (β value) to study and optimize for different acquisition protocols and clinical goals. METHODS: Both phantom and patient images were evaluated. Data from an image quality phantom were acquired using different Lesion-to-Background ratios and acquisition times...
May 21, 2018: Medical Physics
https://www.readbyqxmd.com/read/29782653/data-driven-gating-in-pet-influence-of-respiratory-signal-noise-on-motion-resolution
#11
Florian Büther, Iris Ernst, Lynn Johann Frohwein, Joost Pouw, Klaus Peter Schäfers, Lars Stegger
PURPOSE: Data-driven gating (DDG) approaches for positron emission tomography (PET) are interesting alternatives to conventional hardware-based gating methods. In DDG, the measured PET data themselves are utilized to calculate a respiratory signal that is subsequently used for gating purposes. The success of gating is then highly dependent on the statistical quality of the PET data. In this study we investigate how this quality determines signal noise and thus motion resolution in clinical PET scans using a center-of-mass-based (COM) DDG approach, specifically with regard to motion management of target structures in future radiotherapy planning applications...
May 21, 2018: Medical Physics
https://www.readbyqxmd.com/read/29782617/patient-specific-neurosurgical-phantom-assessment-of-visual-quality-accuracy-and-scaling-effects
#12
Felipe Wilker Grillo, Victor Hugo Souza, Renan Hiroshi Matsuda, Carlo Rondinoni, Theo Zeferino Pavan, Oswaldo Baffa, Helio Rubens Machado, Antonio Adilton Oliveira Carneiro
Background: Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training...
2018: 3D printing in medicine
https://www.readbyqxmd.com/read/29782431/the-influence-of-3d-in-single-port-laparoscopy-surgery-an-experimental-study
#13
Jaime Vilaça, Mariana Leite, Jorge Correia-Pinto, Gerrit Högemann, Patrício Costa, Pedro Leão
The aim of this experimental study was to analyze the effect of 3-dimensional (3D) imaging in laparoendoscopic single-site surgery. End points were time, errors, and preference. Twenty-six participants were enrolled in the study, and these were divided into Beginners and Experts, in exercises either with a 2-dimensional or a 3D system. The 4 phantom exercises were chosen from the E-BLUS-European Training in Basic Laparoscopic Urological Skills from the American Fundamentals of Laparoscopic Surgery (FLS) system...
May 18, 2018: Surgical Laparoscopy, Endoscopy & Percutaneous Techniques
https://www.readbyqxmd.com/read/29780044/-effect-of-misregistration-between-spect-and-ct-images-on-attenuation-correction-for-quantitative-bone-spect-imaging
#14
Mika Sakoshi, Norikazu Matsutomo, Tomoaki Yamamoto, Eisuke Sato
PURPOSE: The aim of this study was to evaluate the effect of misregistration between single-photon emission computed tomography (SPECT) and computed tomography (CT) images on bone SPECT. METHODS: We acquired SPECT and CT images of a body phantom filled with bone-equivalent solution and 99m Tc for evaluation of bone SPECT. SPECT images were reconstructed using attenuation correction maps obtained by shifting the attenuation coefficients from non-shifted values (reference)...
2018: Nihon Hoshasen Gijutsu Gakkai Zasshi
https://www.readbyqxmd.com/read/29779258/hyperpolarized-porous-silicon-nanoparticles-potential-theragnostic-material-for-%C3%A2-%C3%A2-si-magnetic-resonance-imaging
#15
Hyeonglim Seo, Ikjang Choi, Nicholas Whiting, Jingzhe Hu, Quy Son Luu, Shivanand Pudakalakatti, Caitlin McCowan, Yaewon Kim, Niki Zacharias, Seunghyun Lee, Pratip Bhattacharya, Youngbok Lee
Porous silicon nanoparticles have recently garnered attention as potentially-promising biomedical platforms for drug delivery and medical diagnostics. Here, we demonstrate porous silicon nanoparticles as contrast agents for ²⁹Si magnetic resonance imaging. Size-controlled porous silicon nanoparticles were synthesized by magnesiothermic reduction of silica nanoparticles and were surface activated for further functionalization. Particles were hyperpolarized via dynamic nuclear polarization to enhance their ²⁹Si MR signals; the particles demonstrated long ²⁹Si spin-lattice relaxation (T₁) times (~ 25 mins), which suggests potential applicability for medical imaging...
May 20, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
https://www.readbyqxmd.com/read/29777821/regional-cardiac-function-analysis-from-tagged-mri-images-comparison-of-techniques-harmonic-phase-harp-versus-sinusoidal-modeling-sinmod-analysis
#16
El-Sayed H Ibrahim, Jadranka Stojanovska, Azza Hassanein, Claire Duvernoy, Pierre Croisille, Rodica Pop-Busui, Scott D Swanson
Cardiac MRI tagging is a valuable technique for evaluating regional heart function. Currently, there are a number of different techniques for analyzing the tagged images. Specifically, k-space-based analysis techniques showed to be much faster than image-based techniques, where harmonic-phase (HARP) and sine-wave modeling (SinMod) stand as two famous techniques of the former group, which are frequently used in clinical studies. In this study, we compared HARP and SinMod and studied inter-observer variability between the two techniques for evaluating myocardial strain and apical-to-base torsion in numerical phantom, nine healthy controls, and thirty diabetic patients...
May 16, 2018: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29777595/a-ring-based-compensator-imrt-system-optimized-for-low-and-middle-income-countries-design-and-treatment-planning-study
#17
Jonathon Van Schelt, Daniel Smith, Nicholas Fong, Dolla Toomeh, Patricia A Sponseller, Derek W Brown, Meghan W Macomber, Nina A Mayr, Shilpen Patel, Adam Shulman, G V Subrahmanyam, K Govindarajan, Eric C Ford
PURPOSE: We propose a novel compensator-based IMRT system designed to provide a simple, reliable, and cost-effective adjunct technology, with the goal of expanding global access to advanced radiotherapy techniques. The system would employ easily-reusable tungsten bead compensators that operate independent of a gantry (e.g. mounted in a ring around the patient). Thereby the system can be retrofitted to existing linac and cobalt teletherapy units. This study explores the quality of treatment plans from the proposed system and the dependence on associated design parameters...
May 19, 2018: Medical Physics
https://www.readbyqxmd.com/read/29777389/iron-based-metal-organic-frameworks-as-a-theranostic-carrier-for-local-tuberculosis-therapy
#18
Gabriela Wyszogrodzka, Przemysław Dorożyński, Barbara Gil, Wieslaw J Roth, Maciej Strzempek, Bartosz Marszałek, Władysław P Węglarz, Elżbieta Menaszek, Weronika Strzempek, Piotr Kulinowski
PURPOSE: The purpose of the study was initial evaluation of applicability of metal organic framework (MOF) Fe-MIL-101-NH2 as a theranostic carrier of antituberculous drug in terms of its functionality, i.e. drug loading, drug dissolution, magnetic resonance imaging (MRI) contrast and cytotoxic safety. METHODS: Fe-MIL-101-NH2 was characterized using X-ray powder diffraction, FTIR spectrometry and scanning electron microscopy. The particle size analysis was determined using laser diffraction...
May 18, 2018: Pharmaceutical Research
https://www.readbyqxmd.com/read/29776740/development-of-a-deformable-phantom-for-experimental-verification-of-4d-monte-carlo-simulations-in-a-deforming-anatomy
#19
Sara Gholampourkashi, Joanna E Cygler, Bernie Lavigne, Emily Heath
PURPOSE: To verify the accuracy of 4D Monte Carlo (MC) simulations, using the 4DdefDOSXYZnrc user code, in a deforming anatomy. We developed a tissue-equivalent and reproducible deformable lung phantom and evaluated 4D simulations of delivered dose to the phantom by comparing calculations against measurements. METHODS: A novel deformable phantom consisting of flexible foam, emulating lung tissue, inside a Lucite external body was constructed. A removable plug, containing an elastic tumor that can hold film and other dosimeters, was inserted in the phantom...
May 15, 2018: Physica Medica: PM
https://www.readbyqxmd.com/read/29776653/accuracy-of-phase-contrast-velocity-mapping-proximal-and-distal-to-stent-artifact-during-cardiac-magnetic-resonance-imaging
#20
Catherine M Avitabile, Matthew A Harris, Ravi S Doddasomayajula, Steven G Chopski, Matthew J Gillespie, Yoav Dori, Andrew C Glatz, Mark A Fogel, Kevin K Whitehead
Little data are available on the accuracy of phase-contrast magnetic resonance imaging (PC-MRI) velocity mapping in the vicinity of intravascular metal stents other than nitinol stents. Therefore, we sought to determine this accuracy using in vitro experiments. An in vitro flow phantom was used with 3 stent types: (1) 316L stainless steel, (2) nitinol self-expanding, and (3) platinum-iridium. Steady and pulsatile flow was delivered with a magnetic resonance imaging-compatible pump (CardioFlow 5000, Shelley Medical, London, Ontario, Canada)...
April 20, 2018: American Journal of Cardiology
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