In vivo electric conductivity of cervical cancer patients based on B₁⁺ maps at 3T MRI.

abstract：:A post-processing noise suppression technique for biomedical MRI images is presented. The described procedure recovers both sharp edges and smooth surfaces from a given noisy MRI image; it does not blur the edges and does not introduce spikes or other artefacts. The fine details of the image are also preserved. The pr...

journal_title：Physics in medicine and biology

authors： Placidi G,Alecci M,Sotgiu A

更新日期：2003-07-07 00:00:00

abstract：:Target motion is one of the major limitations of each high precision radiation therapy. Using advanced active beam delivery techniques, such as the magnetic raster scanning system for particle irradiation, the interplay between time-dependent beam and target position heavily distorts the applied dose distribution. Thi...

journal_title：Physics in medicine and biology

authors： Li Q,Groezinger SO,Haberer T,Rietzel E,Kraft G

更新日期：2004-07-21 00:00:00

abstract：:New definitions of the absorbed dose conversion factors Clambda and CE are proposed. The absorbed dose in water is given by the product of absorbed dose conversion factor, exposure calibration factor, ionisation chamber reading, cap displacement correction factor and perturbation correction factor. At exposure calibra...

journal_title：Physics in medicine and biology

authors： Shiragai A

更新日期：1978-03-01 00:00:00

abstract：:The standard mammogram form (SMF) representation of an x-ray mammogram is a standardized, quantitative representation of the breast from which the volume of non-fat tissue and breast density can be easily estimated, both of which are of significant interest in determining breast cancer risk. Previous theoretical analy...

journal_title：Physics in medicine and biology

authors： Highnam R,Pan X,Warren R,Jeffreys M,Davey Smith G,Brady M

更新日期：2006-06-07 00:00:00

abstract：:Complex intra-fractional motion and deformation of the liver significantly impacts the accuracy of delivered dose in radiotherapy. It limits margin reduction, dose escalation and normal tissue sparing. A critical component of motion management is to accurately reconstruct tumor motion. In this study, we developed a si...

journal_title：Physics in medicine and biology

authors： Chi Y,Shen C,Li B,Zhang Y,Yang M,Folkert M,Jia X

更新日期：2019-11-21 00:00:00

abstract：:Numerical computations are used to evaluate electric field dosimetry for high-resolution anatomically based inhomogeneous models of a human male child, and male and female rats and mice, under exposure to 60 Hz uniform magnetic field sources of three perpendicular orientations. The goal is to compare the child data to...

journal_title：Physics in medicine and biology

authors： Dawson TW,Caputa K,Stuchly MA

更新日期：2002-07-21 00:00:00

abstract：:Breast MRI is frequently performed prior to breast conserving surgery in order to assess the location and extent of the lesion. Ideally, the surgeon should also be able to use the image information during surgery to guide the excision and this requires that the MR image is co-registered to conform to the patient's pos...

journal_title：Physics in medicine and biology

authors： Ebrahimi M,Siegler P,Modhafar A,Holloway CM,Plewes DB,Martel AL

更新日期：2014-04-07 00:00:00

abstract：:A dual-ended readout PET detector based on two Hamamatsu 16 × 16 arrays of 1 × 1 mm2 SiPMs coupled to both ends of a 25 × 25 array of 0.69 × 0.69 × 20 mm3 polished LYSOs was evaluated in terms of flood histogram, energy resolution, timing resolution, and DOI resolution. The SiPM arrays have a pitch size of 1.2 mm. Eac...

journal_title：Physics in medicine and biology

authors： Du J,Bai X,Cherry SR

更新日期：2020-08-19 00:00:00

abstract：:This paper describes a neural network (NN) regression model for relative dose computation. The input signal of the NN model includes depths and field sizes and the output is the relative dose, for example, percentage depth dose (%DD) or tissue-air ratio (TAR) in this paper. After a functional link has been created, th...

journal_title：Physics in medicine and biology

authors： Wu X,Zhu Y

更新日期：2000-04-01 00:00:00

abstract：:This study investigates the dosimetric impact of using population-based Hounsfield units (HUs) and ICRU-based HUs as a function of the number of tissue segments for bulk density assignment toward MRI-based treatment planning in the abdomen. To avoid potential geometric differences between CT and MR images, CT images r...

journal_title：Physics in medicine and biology

authors： Hsu SH,Zawisza I,O'Grady K,Peng Q,Tomé WA

更新日期：2018-07-24 00:00:00

abstract：:The peak CT number (CT) and full width at half maximum (FWHM) were obtained from the image profiles of aluminium of thickness ranging from 0.1-9.5 mm. The scans were performed at different fields of view (FOVs) and with different reconstruction algorithms ('bone' and 'standard'). Above 3 mm, CT and FWHM provide measur...

journal_title：Physics in medicine and biology

authors： Newman DL,Dougherty G,al Obaid A,al Hajrasy H

更新日期：1998-03-01 00:00:00

abstract：:Dose calculations for radiation arc therapy are traditionally performed by approximating continuous delivery arcs with multiple static beams. For 3D conformal arc treatments, the shape and weight variation per degree is usually small enough to allow arcs to be approximated by static beams separated by 5 degrees -10 de...

journal_title：Physics in medicine and biology

authors： Tang G,Earl MA,Luan S,Wang C,Cao D,Yu CX,Naqvi SA

更新日期：2008-09-07 00:00:00

abstract：:In this paper, we use a more realistic head model with ovoid geometry for approximation of a human head. By inverting the Geselowitz equation, some analytic results on the inverse MEG problem are presented in homogenous ovoid geometry. On one hand, some information about the components of primary current is shown by t...

journal_title：Physics in medicine and biology

authors： Peng L,Cheng J,Jin L

更新日期：2006-11-07 00:00:00

abstract：:Respiratory-correlated 4D-MRI can characterize respiratory-induced motion of tumors and organs-at-risk for radiotherapy treatment planning and is a necessity for image guidance of moving tumors treated on an MRI-linac. Essential for 4D-MRI generation is a robust respiratory surrogate signal. We investigated the feasib...

journal_title：Physics in medicine and biology

authors： Navest RJM,Mandija S,Bruijnen T,Stemkens B,Tijssen RHN,Andreychenko A,Lagendijk JJW,van den Berg CAT

更新日期：2020-01-13 00:00:00

abstract：:Refraction contrast of simple objects obtained using diffraction enhanced imaging (DEI) was studied and compared to conventional radiographic contrast. Lucite cylinders and nylon wires were imaged using monochromatic synchrotron radiation at the National Synchrotron Light Source (http://nslsweb. nsls.bnl.gov/nsls/Defa...

journal_title：Physics in medicine and biology

authors： Kiss MZ,Sayers DE,Zhong Z

更新日期：2003-02-07 00:00:00

abstract：:For quality assurance of hyperthermia treatment planning systems, quantitative validation of the electromagnetic model of an applicator is essential. The objective of this study was to validate a finite-difference time-domain (FDTD) model implementation of the Lucite cone applicator (LCA) for superficial hyperthermia....

journal_title：Physics in medicine and biology

authors： de Bruijne M,Samaras T,Chavannes N,van Rhoon GC

更新日期：2007-06-07 00:00:00

abstract：:The treatment of large tumors such as sarcomas with intra-operative radiotherapy using a Mobetron is often complicated because of the limited field size of the primary collimator and the available applicators (max Ø100 mm). To circumvent this limitation a prototype rectangular applicator of 80 x 150 mm(2) was designed...

journal_title：Physics in medicine and biology

authors： Janssen RW,Faddegon BA,Dries WJ

更新日期：2008-04-21 00:00:00

abstract：:Polymer gel dosimetry aims to provide three-dimensional images of radiation therapy dose distributions in irradiated aqueous gels. The first gels required manufacture in an oxygen-free environment, but later the MAGIC formulation was introduced, which could be made in normal atmospheric conditions. Here we report our ...

journal_title：Physics in medicine and biology

authors： Luci JJ,Whitney HM,Gore JC

更新日期：2007-05-21 00:00:00

abstract：:Cardiac and respiratory motion artefacts in PET imaging have been traditionally resolved by acquiring the data in gated mode. However, gated PET images are usually characterized by high noise content due to their low photon statistics. In this paper, we present a novel 4D model for the PET imaging system, which can in...

journal_title：Physics in medicine and biology

authors： Qiao F,Pan T,Clark JW Jr,Mawlawi OR

更新日期：2006-08-07 00:00:00

abstract：:In recent codes of practice for reference dosimetry in clinical proton beams using ionization chambers, it is recommended to perform the measurement in a water phantom. However, in situations where the positioning accuracy is very critical, it could be more convenient to perform the measurement in a plastic phantom. I...

journal_title：Physics in medicine and biology

authors： Palmans H,Symons JE,Denis JM,de Kock EA,Jones DT,Vynckier S

更新日期：2002-09-07 00:00:00

abstract：:Monolithic scintillation detectors for positron emission tomography and single-photon emission computed tomography (SPECT) imaging have many advantages over pixelated detectors. The use of monolithic crystals allows for reducing the scintillator cost per unit volume and increasing the sensitivity along with the energy...

journal_title：Physics in medicine and biology

authors： España S,Deprez K,Van Holen R,Vandenberghe S

更新日期：2013-07-21 00:00:00

abstract：:Megavoltage (MV) cone-beam computed tomography (CBCT) using an electronic portal imaging (EPID) offers advantageous features, including 3D mapping, treatment beam registration, high-z artifact suppression, and direct radiation dose calculation. Adoption has been slowed by image quality limitations and concerns about i...

journal_title：Physics in medicine and biology

authors： Hu YH,Fueglistaller R,Myronakis M,Rottmann J,Wang A,Shedlock D,Morf D,Baturin P,Huber P,Star-Lack J,Berbeco R

更新日期：2018-06-20 00:00:00

abstract：:The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting...

journal_title：Physics in medicine and biology

authors： Wilson LS,Robinson DE,Dadd MJ

更新日期：2000-06-01 00:00:00

abstract：:Magnetic Particle Imaging (MPI) is a novel technology, which opens new possibilities for promising biomedical applications. MPI uses magnetic fields to generate a specific response from magnetic nanoparticles (MNPs), to determine their spatial location non-invasively and without using ionizing radiation. One open chal...

journal_title：Physics in medicine and biology

authors： Paysen H,Kosch O,Wells J,Loewa N,Wiekhorst F

更新日期：2020-10-21 00:00:00

abstract：:Area laser lathing and trephination of donor corneas is used to produce different types of grafts for human transplantation. 193 nm (ArF excimer) laser radiation is used, since this is known to give a non-thermal laser-tissue interaction with a minimal zone of tissue damage. To guarantee the highest degree of flexibil...

journal_title：Physics in medicine and biology

authors： Homolka P,Biowski R,Kaminski S,Barisani T,Husinsky W,Bergmann H,Grabner G

更新日期：1999-05-01 00:00:00

abstract：:We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, su...

journal_title：Physics in medicine and biology

authors： Chavarrías C,Vaquero JJ,Sisniega A,Rodríguez-Ruano A,Soto-Montenegro ML,García-Barreno P,Desco M

更新日期：2008-09-07 00:00:00

abstract：:Treatment planning for proton tumor therapy requires a fast and accurate dose-calculation method. We have implemented a simplified Monte Carlo (SMC) method in the treatment planning system of the National Cancer Center Hospital East for the double-scattering beam delivery scheme. The SMC method takes into account the ...

journal_title：Physics in medicine and biology

authors： Hotta K,Kohno R,Takada Y,Hara Y,Tansho R,Himukai T,Kameoka S,Matsuura T,Nishio T,Ogino T

更新日期：2010-06-21 00:00:00

abstract：:Compressed sensing (CS) aims to recover images from fewer measurements than that governed by the Nyquist sampling theorem. Most CS methods use analytical predefined sparsifying domains such as total variation, wavelets, curvelets, and finite transforms to perform this task. In this study, we evaluated the use of dicti...

journal_title：Physics in medicine and biology

authors： Valiollahzadeh S,Clark JW,Mawlawi O

更新日期：2015-08-07 00:00:00

abstract：:Recently, the initial 2D physical characterization of a small-diameter positron emission tomograph, designed specifically for scanning of small laboratory animals, was reported. The physical characteristics of the tomograph operating in 3D mode have now been measured and compared to those obtained in 2D mode. In 3D, t...

journal_title：Physics in medicine and biology

authors： Bloomfield PM,Myers R,Hume SP,Spinks TJ,Lammertsma AA,Jones T

更新日期：1997-02-01 00:00:00

abstract：:A pencil beam model for the calculation of the lateral scattering in water of protons for any therapeutic energy and depth is presented. It is based on the full Molière theory, taking into account the energy loss and the effects of mixtures and compounds. Concerning the electromagnetic part, the model has no free para...

journal_title：Physics in medicine and biology

authors： Bellinzona EV,Ciocca M,Embriaco A,Ferrari A,Fontana A,Mairani A,Parodi K,Rotondi A,Sala P,Tessonnier T

更新日期：2016-02-21 00:00:00