Post-processing noise removal algorithm for magnetic resonance imaging based on edge detection and wavelet analysis.

abstract：:Quantitative Yttrium-90 ((90)Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging has shown great potential to provide reliable estimates of (90)Y activity distribution for targeted radionuclide therapy dosimetry applications. One factor that potentially affects the reliability of the activity ...

journal_title：Physics in medicine and biology

authors： Rong X,Du Y,Frey EC

更新日期：2012-06-21 00:00:00

abstract：:An acardiac twin is a severely malformed monochorionic twin fetus that lacks most organs, particularly a heart. It grows during pregnancy, because it is perfused by its developmentally normal co-twin (called the pump twin) via a set of placental arterioarterial and venovenous anastomoses. The pump twin dies intrauteri...

journal_title：Physics in medicine and biology

authors： Umur A,van Gemert MJ,van den Wijngaard JP,Ross MG,Nikkels PG

更新日期：2004-07-21 00:00:00

abstract：:Measuring spin-spin relaxation times (T2) by quantitative MR imaging represents a potentially efficient tool to evaluate the physicochemical properties of various media. However, noise in MR images is responsible for uncertainties in the determination of T2 relaxation times, which limits the accuracy of parametric tis...

journal_title：Physics in medicine and biology

authors： Gensanne D,Josse G,Lagarde JM,Vincensini D

更新日期：2006-06-07 00:00:00

abstract：:Dual spectral computed tomography (DSCT) has a superior material distinguishability than the conventional single spectral computed tomography (SSCT). However, the decomposition process is an illposed problem, which is sensitive to noise. Thus, the decomposed image quality is degraded, and the corresponding signal-to-n...

journal_title：Physics in medicine and biology

authors： Wang Q,Zhu Y,Yu H

更新日期：2017-10-19 00:00:00

abstract：:The local noise property of a 3D PET reconstructed image is investigated for a uniform-activity sphere distributed in a constantly attenuating spherical object. The positional dependence of the statistical noise is approximately derived and calculated for some special cases. It is suggested that a larger diameter of t...

journal_title：Physics in medicine and biology

authors： Murayama H,Nohara N

更新日期：1997-01-01 00:00:00

abstract：:In this study, the safety compliance for nonuniform field exposures is discussed using coupling factor concepts. The coupling factor, which is defined in the International Electrotechnical Commission 62311 standard, is extended to consider the effects of harmonics and also to apply to the specific absorption rate (for...

journal_title：Physics in medicine and biology

authors： Sunohara T,Hirata A,Laakso I,De Santis V,Onishi T

更新日期：2015-10-21 00:00:00

abstract：:We describe a radiation therapy treatment plan optimization method that explicitly considers the effects of interfraction organ motion through optimization on the clinical target volume (CTV), and investigate how it compares to conventional planning using a planning target volume (PTV). The method uses simulated treat...

journal_title：Physics in medicine and biology

authors： Fredriksson A,Engwall E,Andersson B

更新日期：2020-12-21 00:00:00

abstract：:Online adaptive radiation therapy (ART) based on real-time magnetic resonance imaging represents a paradigm-changing treatment scheme. However, conventional quality assurance (QA) methods based on phantom measurements are not feasible with the patient on the treatment couch. The purpose of this work is to develop a fa...

journal_title：Physics in medicine and biology

authors： Wang Y,Mazur TR,Park JC,Yang D,Mutic S,Li HH

更新日期：2017-06-21 00:00:00

abstract：:A computer method has been developed which uses the time domain finite-difference (TDFD) algorithm to calculate the deposition of the electromagnetic (EM) field in three-dimensional biological models. This, the first of two papers, describes the algorithm and the computer programs developed. The method is demonstrated...

journal_title：Physics in medicine and biology

authors： Lau RW,Sheppard RJ

更新日期：1986-11-01 00:00:00

abstract：:A silicon semiconductor photodiode was used to measure the TL-signal of TLD-300 (CaF2:Tm) detectors irradiated with 60Co gamma rays and 226Ra alpha particles. The applied dose values varied from 0.12 to 14.3 Gy for gamma rays and from about 50 to 300 Gy for alpha particles. Because of the infrared sensitivity of the p...

journal_title：Physics in medicine and biology

authors： Meissner P,Jacob M,Rassow J

更新日期：1988-12-01 00:00:00

abstract：:Developments in positron emission tomography (PET) technology have resulted in systems with finer detector elements designed to further improve spatial resolution. However, there is a limit to what extent reducing detector element size will improve spatial resolution in PET. The spatial resolution of PET imaging is li...

journal_title：Physics in medicine and biology

authors： Levin CS,Hoffman EJ

更新日期：1999-03-01 00:00:00

abstract：:Approximately 70% of acute coronary artery disease is caused by unstable (vulnerable) plaques with an inflammation of the overlying cap and high lipid content. A rupturing of the inflamed cap of the plaque results in propagation of the thrombus into the lumen, blockage of the artery and acute ischaemic syndrome or sud...

journal_title：Physics in medicine and biology

authors： Shikhaliev PM,Xu T,Ducote JL,Easwaramoorthy B,Mukherjee J,Molloi S

更新日期：2006-02-21 00:00:00

abstract：:Diffusion weighted magnetic resonance imaging offers a non-invasive tool to explore the three-dimensional structure of brain white matter in clinical practice. Anisotropic diffusion hardware phantoms are useful for the quantitative validation of this technique. This study provides guidelines on how to manufacture anis...

journal_title：Physics in medicine and biology

authors： Fieremans E,De Deene Y,Delputte S,Ozdemir MS,Achten E,Lemahieu I

更新日期：2008-10-07 00:00:00

abstract：:Detailed studies of the basic contrast mechanisms in computerized transverse axial tomography scanners have been carried out. Contrast is related to the effective atomic numbers and electron densities of materials and the resultant linear attenuation coefficients. We have therefore quantitatively evaluated various sam...

journal_title：Physics in medicine and biology

authors： Tsai CM,Cho ZH

更新日期：1976-07-01 00:00:00

abstract：:We report a simulation study on diffuse reflective optical computed tomography, in which continuous-wave sources and detectors are placed on the plane surface of a semi-infinite body. We adopted a simple Tikhonov regularization in the inverse problem and demonstrated the feasibility of three-dimensional reconstruction...

journal_title：Physics in medicine and biology

authors： Endoh R,Suzuki A,Fujii M,Nakayama K

更新日期：2004-05-21 00:00:00

abstract：:In this study, two computational phantoms of the newborn patient were used to assess individual organ doses and effective doses delivered during head, chest, abdomen, pelvis, and torso examinations using the Siemens SOMATOM Sensation 16 helical multi-slice computed tomography (MSCT) scanner. The stylized phantom used ...

journal_title：Physics in medicine and biology

authors： Staton RJ,Lee C,Lee C,Williams MD,Hintenlang DE,Arreola MM,Williams JL,Bolch WE

更新日期：2006-10-21 00:00:00

abstract：:All particle beam scanning systems are subject to dose delivery errors due to errors in position, energy and intensity of the delivered beam. In addition, finite scan speeds, beam spill non-uniformities, and delays in detector, detector electronics and magnet responses will all contribute errors in delivery. In this p...

journal_title：Physics in medicine and biology

authors： Coutrakon G,Wang N,Miller DW,Yang Y

更新日期：2010-12-07 00:00:00

abstract：:Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the card...

journal_title：Physics in medicine and biology

authors： Du Y,Bhattacharya M,Frey EC

更新日期：2014-06-07 00:00:00

abstract：:Several recent reports agree that the potentially dangerous heating around extended wires or coaxial cables inside the bodycoil of a magnetic resonance imager is related to resonant effects. No quantitative description of this idea has been given so far. We analyse a simplified situation, where a straight metallic wir...

journal_title：Physics in medicine and biology

authors： Pictet J,Meuli R,Wicky S,van der Klink JJ

更新日期：2002-08-21 00:00:00

abstract：:Noise equivalent count rate (NECR) and image noise are two different but related metrics that have been used to predict and assess image quality, respectively. The aim of this study is to investigate, using patient studies, the relationships between injected dose (ID), body mass index (BMI) and scanner type on NECR an...

journal_title：Physics in medicine and biology

authors： Chang T,Chang G,Kohlmyer S,Clark JW,Rohren E,Mawlawi OR

更新日期：2011-08-21 00:00:00

abstract：:In this paper, Novikov's inversion formula of the attenuated two-dimensional (2D) Radon transform is applied to the reconstruction of attenuated fan-beam projections acquired with equal detector spacing and of attenuated cone-beam projections acquired with a flat planar detector and circular trajectory. The derivation...

journal_title：Physics in medicine and biology

authors： Huang Q,Zeng GL,You J,Gullberg GT

更新日期：2005-05-21 00:00:00

abstract：:A number of radiation-therapy-related uses based on a commercially available spreadsheet program have been developed at our facility. The graphics and display capabilities inherent in these spreadsheet programs allow for concise visual results. The spreadsheets are used as an independent check for several types of rad...

journal_title：Physics in medicine and biology

authors： Balog JP,Sibata CH,Podgorsak MB,Shin KH

更新日期：1995-06-01 00:00:00

abstract：:Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contras...

journal_title：Physics in medicine and biology

authors： Tsai CH,Zhang JW,Liao YY,Liu HL

更新日期：2016-04-07 00:00:00

abstract：:High-resolution computations of induced fields are used to assess equivalent source levels for human exposure to uniform low-frequency electric and magnetic fields. These results pertain to 60 Hz foot-to-head electric excitation of the body in three positions with respect to a ground plane, and to magnetic excitation ...

journal_title：Physics in medicine and biology

authors： Dawson TW,Caputa K,Stuchly MA

更新日期：1997-12-01 00:00:00

abstract：:Most tissue characterization methods use RF data originating from backscattering processes in the insonified tissue. Characterization of the tissue of a thin layer (e.g., an artery wall) poses problems because of the small amount of data available. The tissue layer may be so thin that there are no RF data that are not...

journal_title：Physics in medicine and biology

authors： Linssen FM,Hoeks AP,Brands PJ

更新日期：1991-10-01 00:00:00

abstract：:Energy-resolved attenuation data in spectral x-ray imaging enables material decomposition, in which the different materials inside an object can be identified and separated virtually. Material decomposition has the drawback of increased noise in the resulting material images relative to the measured images. Recently, ...

journal_title：Physics in medicine and biology

authors： Schaff F,Morgan KS,Paganin DM,Kitchen MJ

更新日期：2020-10-07 00:00:00

abstract：:Computational simulations, such as Monte Carlo track structure simulations, offer a powerful tool for quantitatively investigating radiation interactions within cells. The modelling of the spatial distribution of energy deposition events as well as diffusion of chemical free radical species, within realistic biologica...

journal_title：Physics in medicine and biology

authors： McNamara AL,Ramos-Méndez J,Perl J,Held K,Dominguez N,Moreno E,Henthorn NT,Kirkby KJ,Meylan S,Villagrasa C,Incerti S,Faddegon B,Paganetti H,Schuemann J

更新日期：2018-09-06 00:00:00

abstract：:A single photon absorptiometry method to measure the arterial concentration of injected iodinated contrast agent was developed. A prototype absorptiometry unit was built which consists of either a square or circular cross section acrylic (polymethylmethacrylate) cuvette connected to an arterial catheter at one end and...

journal_title：Physics in medicine and biology

authors： Yeung WT,Lee TY,Del Maestro RF,Kozak R,Bennett JD,Brown T

更新日期：1992-09-01 00:00:00

abstract：:Computer tomographic (CT) scans are used to correct for tissue inhomogeneities in radiotherapy treatment planning. In order to guarantee a precise treatment, it is important to obtain the relationship between CT Hounsfield units and electron densities (or proton stopping powers for proton radiotherapy), which is the b...

journal_title：Physics in medicine and biology

authors： Schneider U,Pedroni E,Lomax A

更新日期：1996-01-01 00:00:00

abstract：:We introduce a novel x-ray imaging approach that yields information about the local texture of structures smaller than the image pixel resolution inside an object. The approach is based on a recently developed x-ray dark-field imaging technique, using scattering from sub-micron structures in the sample. We show that t...

journal_title：Physics in medicine and biology

authors： Jensen TH,Bech M,Bunk O,Donath T,David C,Feidenhans'l R,Pfeiffer F

更新日期：2010-06-21 00:00:00