Transverse tomosynthesis on a digital simulator.

abstract：PURPOSE:In the past decade, phase-contrast imaging (PCI) has been applied to study different kinds of tissues and human body parts, with an increased improvement of the image quality with respect to simple absorption radiography. A technique closely related to PCI is phase-retrieval imaging (PRI). Indeed, PCI is an ima...

journal_title：Medical physics

authors： De Caro L,Scattarella F,Giannini C,Tangaro S,Rigon L,Longo R,Bellotti R

更新日期：2010-07-01 00:00:00

abstract：:The image artifacts characteristic of a scanning chest radiographic system are reviewed. The technique employs a pulsed beam of radiation swept in an overlapping raster pattern that can result in severe ripple and scan line artifacts with improper scanning parameters. A one-dimensional treatment of the scanner geometr...

journal_title：Medical physics

authors： Plewes DB,Vogelstein E

更新日期：1984-03-01 00:00:00

abstract：:A modified neutron production target assembly has been developed to provide improved performance of the proton-cyclotron-based neutron radiotherapy facility at the University of Washington for applications involving neutron capture enhanced fast-neutron therapy. The new target produces a neutron beam that yields essen...

journal_title：Medical physics

authors： Nigg DW,Wemple CA,Risler R,Hartwell JK,Harker YD,Laramore GE

更新日期：2000-02-01 00:00:00

abstract：PURPOSE:Measured values of ultrasound attenuation in bone represent a combination of different loss mechanisms. As a wave is transmitted from a fluid into bone, reflections occur at the interface. In the bone, mode conversion occurs between longitudinal and shear modes and the mechanical wave is scattered by its comple...

journal_title：Medical physics

authors： Pinton G,Aubry JF,Bossy E,Muller M,Pernot M,Tanter M

更新日期：2012-01-01 00:00:00

abstract：PURPOSE:The authors investigate performance of thin-film cadmium telluride (CdTe) in detecting high-energy (6 MV) x rays. The utilization of this material has become technologically feasible only in recent years due to significant development in large area photovoltaic applications. METHODS:The CdTe film is combined w...

journal_title：Medical physics

authors： Parsai EI,Shvydka D,Kang J

更新日期：2010-08-01 00:00:00

abstract：PURPOSE:A 3-year project called LABSYNC has been recently funded by the European Commission, with the aim of designing a radiation facility based on a compact light source, i.e., a laboratory-sized commercial synchrotron, capable of accelerating electrons up to 6 or 20 MeV. An accurate spectral description of hard x ra...

journal_title：Medical physics

authors： Marziani M,Taibi A,Di Domenico G,Gambaccini M

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:Optically stimulated luminescence (OSL) dosimetry has been recently introduced in radiation therapy as a potential alternative to the thermoluminescent dosimeter (TLD) system. The aim of this study was to investigate the feasibility of using OSL point dosimeters in the energy range used in diagnostic imaging. ...

journal_title：Medical physics

authors： Al-Senan RM,Hatab MR

更新日期：2011-07-01 00:00:00

abstract：PURPOSE:To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch tra...

journal_title：Medical physics

authors： MacDonald RL,Syme A,Little B,Ward L,Thomas CG

更新日期：2020-02-01 00:00:00

abstract：:Fluoroscopy is a low dose imaging technique. As such, a very sensitive detector is required to create images of good quality. Present day flat panel active matrix read out systems introduce an amount of noise that inhibits present direct and indirect methods from producing optimal quality images at fluoroscopic exposu...

journal_title：Medical physics

authors： Hunt DC,Kirby SS,Rowlands JA

更新日期：2002-11-01 00:00:00

abstract：:Results of an 18-alternative forced-choice experiment have shown that observers were capable of detecting a signal with a contrast of 1 in terms of 10-bit data which were displayed on a CRT monitor with an 8-bit video generator and a window width setting of 1024. We investigated the conditions under which 10-bit signa...

journal_title：Medical physics

authors： Giger ML,Ohara K,Doi K

更新日期：1986-05-01 00:00:00

abstract：:Intensity Modulated Arc Therapy (IMAT) is a rotational variant of Intensity Modulated Radiation Therapy (IMRT) that can be implemented with or without angular dose rate optimization. The purpose of this study is to determine the inter-relationship among arc range, Multi-Leaf Collimator (MLC) leaf positions and angular...

journal_title：Medical physics

authors： Oliver M,Chen J,Wong E

更新日期：2008-07-01 00:00:00

abstract：:Monte Carlo simulations of x-ray beams typically take parameters of the electron beam in the accelerating waveguide to be free parameters. In this paper, a methodology is proposed and implemented to determine the energy, spectral width, and beam divergence of the electron source. All treatment head components were rem...

journal_title：Medical physics

authors： Sawkey DL,Faddegon BA

更新日期：2009-03-01 00:00:00

abstract：PURPOSE:As radiation therapy evolves toward more adaptive techniques, image guidance plays an increasingly important role, not only in patient setup but also in monitoring the delivered dose and adapting the treatment to patient changes. This study aimed to validate a method for evaluation of delivered intensity modula...

journal_title：Medical physics

authors： Moteabbed M,Sharp GC,Wang Y,Trofimov A,Efstathiou JA,Lu HM

更新日期：2015-01-01 00:00:00

abstract：:Optimal visualization of moving structures such as the heart and coronary arteries using digital radiographic imaging systems is a difficult problem that can involve tradeoffs between temporal, spatial, and density resolution. The motion dependence of four angiographic measures of vessel dimensions is given and demons...

journal_title：Medical physics

authors： Parker DL,Clayton PD,Gustafson DE

更新日期：1985-11-01 00:00:00

abstract：PURPOSE:To build a statistical model to quantitatively correlate the anatomic features of structures and the corresponding dose-volume histogram (DVH) of head and neck (HN) Tomotherapy (Tomo) plans. To study if the model built upon one intensity modulated radiation therapy (IMRT) technique (such as conventional Linac) ...

journal_title：Medical physics

authors： Lian J,Yuan L,Ge Y,Chera BS,Yoo DP,Chang S,Yin F,Wu QJ

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:Mammographic density of glandular breast tissue has a masking effect that can reduce lesion detection accuracy and is also a strong risk factor for breast cancer. Therefore, accurate quantitative estimation of breast density is clinically important. In this study, we investigate experimentally the feasibility o...

journal_title：Medical physics

authors： Ghammraoui B,Badal A,Glick SJ

更新日期：2018-06-03 00:00:00

abstract：:A method to significantly reduce the exposure area product in fluoroscopy using a pre-patient region-of-interest (ROI) attenuator is presented. The attenuator has a thin central region and a gradually increasing thickness away from the center. It is shown that the unwanted brightening artifact caused by the attenuator...

journal_title：Medical physics

authors： Robert N,Komljenovic PT,Rowlands JA

更新日期：2002-05-01 00:00:00

abstract：PURPOSE:Transcranial magnetic resonance-guided focused ultrasound surgery is a noninvasive technique for causing selective tissue necrosis. Variations in density, thickness, and shape of the skull cause aberrations in the location and shape of the focal zone. In this paper, the authors propose a hybrid simulation-MR-AR...

journal_title：Medical physics

authors： Vyas U,Kaye E,Pauly KB

更新日期：2014-03-01 00:00:00

abstract：:Recently, the clinical application of electronic portal imaging devices has enabled more frequent verification of patient setup for radiation treatment. However, the image quality has sometimes proven to be inadequate, motivating the investigation of alternative sensors with better image quality. Amorphous selenium (a...

journal_title：Medical physics

authors： Mah D,Rowlands JA,Rawlinson JA

更新日期：1998-04-01 00:00:00

abstract：PURPOSE:In fluoroscopy-guided clinical procedures that involve tracking objects over long treatment times, there is a need for reducing the amount of imaging dose delivered to the patient and the operating staff. In this study, we introduce a feedback metric to minimize tube current while maintaining a targeting precis...

journal_title：Medical physics

authors： Siddique S,Fiume E,Jaffray D

更新日期：2012-06-01 00:00:00

abstract：:The intensity of Compton scattered photons is directly proportional to the electron density of a substance; therefore it is possible to detect changes in electron density by this noninvasive method. The source-detector geometry has been varied to study the effects of geometry on the calculated electron density values,...

journal_title：Medical physics

authors： Huddleston AL,Sackler JP

更新日期：1985-01-01 00:00:00

abstract：:A novel iterative penalized likelihood algorithm with evolutionary components for the optimization of beamlet fluences for intensity modulated radiation therapy (IMRT) is presented. This algorithm is designed to be flexible in terms of the objective function and automatically escalates dose, as long as the objective f...

journal_title：Medical physics

authors： Baydush AH,Marks LB,Das SK

更新日期：2004-08-01 00:00:00

abstract：:Computer algorithms for rotational therapy beams, in most cases, perform dose calculations by summing stored fixed beam data at finite angular steps. Such an algorithm, based on the Bentley beam model, was evaluated by comparing calculations with measured data for an 18-MV x-ray beam. Measurements were made in a speci...

journal_title：Medical physics

authors： Kurup RG,Hogstrom KR,Hwang CC

更新日期：1987-11-01 00:00:00

abstract：:The last 50 years have seen great advances in the accuracy of external beam radiation therapy. Geometrical uncertainties have been reduced from a centimeter or more in presimulation, skin-mark guided days to 1-2 mm in today's image-guided radiation therapy treatments. Medical physicists, with the support and guidance ...

journal_title：Medical physics

authors： Yorke ED,Keall P,Verhaegen F

更新日期：2008-03-01 00:00:00

abstract：:We present a theoretical development and experimental verification of a description of power loss and sample resistance for a lossy sample in a nuclear magnetic resonance radio frequency coil for a sample geometry where the eddy current streamlines are disrupted from their usually assumed circular paths. Specifically ...

journal_title：Medical physics

authors： Harpen MD

更新日期：1989-09-01 00:00:00

abstract：PURPOSE:This paper describes the low-kV spectral optimization of dual-energy CT (DECT) equipped with high-kV tin filtration for the quantitative acquisition of electron density information, which is essential for treatment planning in radiotherapy. In addition, an analytical DECT image simulation was preliminarily perf...

journal_title：Medical physics

authors： Saito M

更新日期：2011-06-01 00:00:00

abstract：:A method is developed to smooth intensity-modulated beam delivery while considering hardware constraints. The method uses matrix algebra to model MLC leaf motion and hardware constraints such as interleaf digitization, synchronization requirements, and intersegment field abutment to deliver intensity modulated beam se...

journal_title：Medical physics

authors： Ma L

更新日期：2002-12-01 00:00:00

abstract：PURPOSE:In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS:The presented edge illumination system is based o...

journal_title：Medical physics

authors： Massimi L,Meganck JA,Towns R,Olivo A,Endrizzi M

更新日期：2020-10-27 00:00:00

abstract：PURPOSE:Air-communicating well ionization chambers are commonly used to assess air kerma strength of sources used in brachytherapy. The signal produced is supposed to be proportional to the air density within the chamber and, therefore, a density-independent air kerma strength is obtained when the measurement is correc...

journal_title：Medical physics

authors： Tornero-López AM,Guirado D,Perez-Calatayud J,Ruiz-Arrebola S,Simancas F,Gazdic-Santic M,Lallena AM

更新日期：2013-12-01 00:00:00

abstract：PURPOSE:To evaluate the feasibility of using an objective computer-aided system to assess bladder cancer stage in CT Urography (CTU). MATERIALS AND METHODS:A dataset consisting of 84 bladder cancer lesions from 76 CTU cases was used to develop the computerized system for bladder cancer staging based on machine learnin...

journal_title：Medical physics

authors： Garapati SS,Hadjiiski L,Cha KH,Chan HP,Caoili EM,Cohan RH,Weizer A,Alva A,Paramagul C,Wei J,Zhou C

更新日期：2017-11-01 00:00:00