Fourier transform infrared imaging and small angle x-ray scattering as a combined biomolecular approach to diagnosis of breast cancer.

abstract：PURPOSE:High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To ...

journal_title：Medical physics

authors： Guthier CV,Devlin PM,Harris TC,O'Farrell DA,Cormack RA,Buzurovic I

更新日期：2020-03-01 00:00:00

abstract：:Results of a human observer performance study using a new ultrasound contrast-detail (CD) phantom are reported. The new phantom allows estimates of the fundamental statistical uncertainties involved in CD analysis. Results of these experiments show that observers generally considered to be "trained" require experience...

journal_title：Medical physics

authors： Hall TJ,Insana MF,Soller NM,Harrison LA

更新日期：1993-01-01 00:00:00

abstract：:Many problems in physics involve imaging objects with high spatial frequency content in a limited amount of time. The limitation of available experimental data leads to the infamous problem of diffraction limited data which manifests itself by causing ringing in the image. This ringing is due to the interference pheno...

journal_title：Medical physics

authors： Haacke EM,Liang ZP,Izen SH

更新日期：1989-05-01 00:00:00

abstract：:This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperatu...

journal_title：Medical physics

authors： Lin WL,Liauh CT,Chen YY,Liu HC,Shieh MJ

更新日期：2000-05-01 00:00:00

abstract：:Transthoracic electrical impedance Z consists of a constant baseline component Z0 and the time variable component delta Z such that Z = Z0 + delta Z. The first time derivative of Z has a negative peak, the magnitude of which is (dZ/dt)min. Measurements of 170 volunteers show that (dZ/dt)min is a function of the consta...

journal_title：Medical physics

authors： Djordjevich L,Sadove MS

更新日期：1981-01-01 00:00:00

abstract：PURPOSE:It is very important for calculation of clinical indices and diagnosis to detect thyroid nodules from ultrasound images. However, this task is a challenge mainly due to heterogeneous thyroid nodules with distinct components are similar to background in ultrasound images. In this study, we employ cascade deep co...

journal_title：Medical physics

authors： Ma J,Wu F,Jiang T,Zhu J,Kong D

更新日期：2017-05-01 00:00:00

abstract：:In this x-ray/MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is approximately 0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an additional...

journal_title：Medical physics

authors： Wen Z,Fahrig R,Williams ST,Pelc NJ

更新日期：2008-09-01 00:00:00

abstract：PURPOSE:The simultaneous measurement of PET and magnetic resonance imaging (MRI) is an emerging field for molecular imaging research. Although optical fiber based PET∕MRI systems have advantages on less interference between PET and MRI, there is a drawback in reducing the scintillation light due to the fiber. To reduce...

journal_title：Medical physics

authors： Yamamoto S,Watabe H,Kanai Y,Watabe T,Aoki M,Sugiyama E,Kato K,Hatazawa J

更新日期：2012-11-01 00:00:00

abstract：:The output factor for a therapy photon beam is defined as the dose per monitor unit relative to the dose per monitor unit in a reference field. Convolution models for photon dose calculations yield the dose in units normalized to the incident energy fluence with phantom scatter intrinsically modeled. Output factors ca...

journal_title：Medical physics

authors： Ahnesjö A,Knöös T,Montelius A

更新日期：1992-03-01 00:00:00

abstract：PURPOSE:An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. METHODS:Optimized ...

journal_title：Medical physics

authors： Kum O

更新日期：2018-06-01 00:00:00

abstract：:Current dosimetry protocols for clinical protons do not take into account any secondary electron fluence perturbation in ion chambers. In this work, we performed a systematic study of secondary electron fluence perturbation factors for spherical and cylindrical ion chambers in proton beams (70-250 MeV). The electron f...

journal_title：Medical physics

authors： Verhaegen F,Palmans H

更新日期：2001-10-01 00:00:00

abstract：PURPOSE:To achieve more translatable preclinical research results, small animal irradiation needs to more closely simulate human radiotherapy. Although the clinical gold standard is intensity-modulated radiation therapy (IMRT), the direct translation of this method for small animals is impractical. In this study we des...

journal_title：Medical physics

authors： Woods K,Nguyen D,Neph R,Ruan D,O'Connor D,Sheng K

更新日期：2019-12-01 00:00:00

abstract：:A nondestructive and noninvasive method for numeric characterization (quantification) of the structural composition of human bone tissue has been developed and tested. In order to quantify and to compare the structural composition of bones from 2D computed tomography (CT) images acquired at different skeletal location...

journal_title：Medical physics

authors： Saparin P,Thomsen JS,Kurths J,Beller G,Gowin W

更新日期：2006-10-01 00:00:00

abstract：:We believe that, for the purpose of evaluation and optimization of treatment plans, quasirandom sampling is superior to grid sampling and should be the method of choice. We believe it to be on average more efficient than grid sampling (i.e., more accurate for any given number of dose estimates) and, even more importan...

journal_title：Medical physics

authors： Niemierko A,Goitein M

更新日期：1993-09-01 00:00:00

abstract：:The physical factors that govern 2D and 3D imaging performance may be understood from quantitative analysis of the spatial-frequency-dependent signal and noise transfer characteristics [e.g., modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta...

journal_title：Medical physics

authors： Tward DJ,Siewerdsen JH

更新日期：2008-12-01 00:00:00

abstract：:The Gafchromic EBT was recently introduced in film dosimetry for external beam therapy (EBT). The high spatial resolution, weak energy dependence, and near-tissue equivalence of EBT films make them suitable for measurement of dose distributions in radiotherapy, especially intensity-modulated radiation therapy (IMRT). ...

journal_title：Medical physics

authors： Fiandra C,Ricardi U,Ragona R,Anglesio S,Giglioli FR,Calamia E,Lucio F

更新日期：2006-11-01 00:00:00

abstract：:The dose distribution for an ovoid with a new tungsten shielding design was determined using Monte Carlo simulation. Standard Cesium-137 tube sources, tungsten shielding, and aluminum ovoid applicator were each modeled as a collection of solid objects. Dose was calculated in planes above, below, in front of, and on th...

journal_title：Medical physics

authors： Weeks KJ

更新日期：1998-12-01 00:00:00

abstract：PURPOSE:4d cone-beam computed tomography (CBCT) scans are usually reconstructed by extracting the motion information from the 2d projections or an external surrogate signal, and binning the individual projections into multiple respiratory phases. In this "after-the-fact" binning approach, however, projections are uneve...

journal_title：Medical physics

authors： Fast MF,Wisotzky E,Oelfke U,Nill S

更新日期：2013-09-01 00:00:00

abstract：:An optimization analysis of digital fluoroscopy has been carried out using (signal/noise)2/dose as a figure of merit. Three signal detection tasks have been considered: (i) small iodine-containing blood vessels; (ii) regions of fat; and (iii) microcalcifications. The effects of x-ray beam filtration and kilovoltage on...

journal_title：Medical physics

authors： Zamenhof RG

更新日期：1982-09-01 00:00:00

abstract：PURPOSE:The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast- and noise-dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial-resolution measurements at very low-contrast levels. The purpose of th...

journal_title：Medical physics

authors： Yu L,Vrieze TJ,Leng S,Fletcher JG,McCollough CH

更新日期：2015-05-01 00:00:00

abstract：:We have measured the linearity, spatial resolution (MTF), noise (NPS), and signal-to-noise characteristics (DQE) of an electronic portal imaging device (EPID) based on an amorphous silicon flat-panel array. The array has a 128 x 128-pixel matrix and each pixel is 0.75 x 0.75 mm2 in dimension so the array covers an are...

journal_title：Medical physics

authors： Munro P,Bouius DC

更新日期：1998-05-01 00:00:00

abstract：:A new calibration algorithm (GLAaS) to derive absolute dose maps from images acquired with the Varian PV-aS500 electronic portal imager (based on amorphous silicon detectors) has been developed incorporating the dependence of detector response on primary and transmitted radiation and on field size. Detector calibratio...

journal_title：Medical physics

authors： Nicolini G,Fogliata A,Vanetti E,Clivio A,Cozzi L

更新日期：2006-08-01 00:00:00

abstract：PURPOSE:The objectives of this study were (a) to devise a technique for measuring quantum noise in clinical body computed tomography (CT) images and (b) to develop a model for predicting that noise with high accuracy. METHODS:The study included 83 clinical image sets at two dose levels (clinical and 50% reduced dose l...

journal_title：Medical physics

authors： Tian X,Samei E

更新日期：2016-01-01 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：:Energy imparted is a measure of the total ionizing energy deposited in the patient during a radiologic examination and may be used to quantify the patient dose in diagnostic radiology. Values of the energy imparted per unit exposure-area product, omega (z), absorbed by a semi-infinite water phantom with a thickness z,...

journal_title：Medical physics

authors： Gkanatsios NA,Huda W

更新日期：1997-04-01 00:00:00

abstract：PURPOSE:The hematopoietically active tissues of skeletal bone marrow are a prime target for computational dosimetry given potential risks of leukemia and, at higher dose levels, acute marrow toxicity. The complex three-dimensional geometry of trabecular spongiosa, however, complicates schema for dose assessment in such...

journal_title：Medical physics

authors： Geyer AM,Schwarz BC,Hobbs RF,Sgouros G,Bolch WE

更新日期：2017-01-01 00:00:00

abstract：:The purpose of this work is to calculate the dose perturbations due to the presence of iodine contrast media in catheter-based intravascular brachytherapy (IVBT). The EGSnrc Monte Carlo system was used to perform the calculation for the two most commonly used beta and gamma sources (90Sr and 192Ir as well as for a var...

journal_title：Medical physics

authors： Li XA

更新日期：2001-05-01 00:00:00

abstract：:We designed a novel force/torque moment transducer with six degrees of freedom. This new sensor is used for measuring the forces and torque moments exerted by static magnetic resonance imaging (MRI) fields on various medical implants, instruments, and ballistic shell fragments. To determine the location of strongest e...

journal_title：Medical physics

authors： Planert J,Modler H,Vosshenrich R

更新日期：1996-06-01 00:00:00

abstract：PURPOSE:With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using ...

journal_title：Medical physics

authors： Liu P,Badano A

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lung...

journal_title：Medical physics

authors： Wang J,Li F,Li Q

更新日期：2009-10-01 00:00:00