Abstract:
:Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of different size (REMCOM/Hershey and Virtual Family), simulating adult and child bodies, are exposed to a 10 MHz pass-by panel-type EAS consisting of two overlapping current-carrying coils. Two different relative positions between the EAS and the body (frontal and lateral exposures), which imply the exposure of different parts of the body at different distances, have been considered. In all cases, induced current densities in tissues of the central nervous system and specific absorption rates (SARs) are calculated to be compared with the limits from the guidelines. Results show that induced current densities are lower in the case of adult models as compared with those of children in both lateral and frontal exposures. Maximum SAR values calculated in lateral exposure are significantly lower than those calculated in frontal exposure, where the EAS-body distance is shorter. Nevertheless, in all studied cases, with an EAS driving current of 4 A rms, maximum induced current and SAR values are below basic restrictions.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Martínez-Búrdalo M,Sanchis A,Martín A,Villar Rdoi
10.1088/0031-9155/55/4/009subject
Has Abstractpub_date
2010-02-21 00:00:00pages
1041-55issue
4eissn
0031-9155issn
1361-6560pii
S0031-9155(10)31649-6journal_volume
55pub_type
杂志文章abstract::Monte Carlo-based simulation of positron emission tomography (PET) data plays a key role in the design and optimization of data correction and processing methods. Our first aim was to adapt and configure the PET-SORTEO Monte Carlo simulation program for the geometry of the widely distributed Inveon PET preclinical sca...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/19/6749
更新日期:2013-10-07 00:00:00
abstract::Radiobiological models for estimating normal tissue complication probability (NTCP) are increasingly used in order to quantify or optimize the clinical outcome of radiation therapy. A good NTCP model should fulfill at least the following two requirements: (a) it should predict the sigmoid shape of the corresponding do...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/22/016
更新日期:2008-11-21 00:00:00
abstract::Dose calculation for radiotherapy with protons and heavier ions deals with a large volume of path integrals involving a scattering power of body tissue. This work provides a simple model for such demanding applications. There is an approximate linearity between RMS end-point displacement and range of incident particle...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/5/N01
更新日期:2009-03-07 00:00:00
abstract::A comprehensive set of measurements and calculations has been conducted to investigate the accuracy of the Dose Planning Method (DPM) Monte Carlo code for electron beam dose calculations in heterogeneous media. Measurements were made using 10 MeV and 50 MeV minimally scattered, uncollimated electron beams from a racet...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/11/301
更新日期:2002-06-07 00:00:00
abstract::We investigated the physical characteristics of two complementary metal oxide semiconductor (CMOS) mammography detectors. The detectors featured 14-bit image acquisition, 50 microm detector element (del) size and an active area of 5 cm x 5 cm. One detector was a passive-pixel sensor (PPS) with signal amplification per...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/6/022
更新日期:2009-03-21 00:00:00
abstract::Using iterative three-dimensional (3D) reconstruction techniques for reconstruction of positron emission tomography (PET) is not feasible on most single-processor machines due to the excessive computing time needed, especially so for the large sinogram sizes of our high-resolution research tomograph (HRRT). In our fir...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/15/307
更新日期:2002-08-07 00:00:00
abstract::At certain frequencies, when the human head becomes a resonant structure, the power absorbed by the head and neck, when the body is exposed to a vertically polarized plane wave propagating from front to back, becomes significantly larger than would ordinarily be expected from its shadow cross section. This has possibl...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/43/8/026
更新日期:1998-08-01 00:00:00
abstract::Chronic liver disease (CLD) is currently one of the major causes of death worldwide. If not treated, it may lead to cirrhosis, hepatic carcinoma and death. Ultrasound (US) shear wave elastography (SWE) is a relatively new, popular, non-invasive technique among radiologists. Although many studies have been published va...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/abae06
更新日期:2020-11-05 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
pub_type: 杂志文章
doi:10.1088/0031-9155/61/4/N102
更新日期:2016-02-21 00:00:00
abstract::A mathematical model has been constructed to simulate the response of cells in vitro to fractionated doses of radiation. The model is capable of describing most of the radiobiological functions that are commonly studied. Input data are measurable cell properties. The details of the model and methods of acquiring the i...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/21/5/011
更新日期:1976-09-01 00:00:00
abstract::We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized....
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/1/301
更新日期:2002-01-07 00:00:00
abstract::Ion beam radiotherapy exploits the finite range of ion beams and the increased dose deposition of ions toward the end of their range in material. This results in high dose conformation to the target region, which can be further increased using scanning ion beams. The standard method for patient-plan verification in io...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/6/1725
更新日期:2013-03-21 00:00:00
abstract::Iterative image reconstruction algorithms have the potential to produce low noise images. Early stopping of the iteration process is problematic because some features of the image may converge slowly. On the other hand, there may be noise build-up with increased number of iterations. Therefore, we examined the stabili...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/20/004
更新日期:2004-10-21 00:00:00
abstract::Microbeam radiation therapy (MRT) is a pre-clinical, spatially-fractionated treatment modality noted for its ability to achieve a large differential response between normal and tumoral tissues. In the present study, TOPAS Monte Carlo (MC) simulations were used to optimize the design of a compact, affordable multi-slit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aad7e2
更新日期:2018-08-29 00:00:00
abstract::We present a new method for automated characterization of atherosclerotic plaque composition in ex vivo MRI. It uses MRI intensities as well as four other types of features: smoothed, gradient magnitude and Laplacian images at several scales, and the distances to the lumen and outer vessel wall. The ground truth for f...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/1/241
更新日期:2012-01-07 00:00:00
abstract::Respiratory gating based on external surrogates is performed in many clinics. We have developed a new technique for treatment verification using an electronic portal imaging device (EPID) in cine mode for gated 3D conformal therapy. Implanted radiopaque fiducial markers inside or near the target are required for this ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/50/16/002
更新日期:2005-08-21 00:00:00
abstract::This study aims at developing an optimization strategy for photon-beam dosimetry in magnetic fields using ionization chambers. Similar to the familiar case in the absence of a magnetic field, detectors should be selected under the criterion that their measured 2D signal profiles M(x,y) approximate the absorbed dose to...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aab50c
更新日期:2018-03-29 00:00:00
abstract::Single monochromator charge-coupled device (CCD) array spectroradiometers have the advantage of ease of use and speed compared with double grating instruments. Their inherently inferior stray-light rejection, however, can critically affect their accuracy in phototherapy and research-related dosimetry applications. Thi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/18/026
更新日期:2008-09-21 00:00:00
abstract::A modified sector-integration method is presented that can predict the output factors of irregular shaped electron fields even in the case of extended source to surface distance (SSD). The model takes as input measured output factors for circular inserts of various radii. These circular fields were measured at SSDs of...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/45/11/318
更新日期:2000-11-01 00:00:00
abstract::The use of liquid ionization chambers in radiotherapy has grown during the past few years. While for air ionization chambers the k(TP) correction for air mass density due to pressure and temperature variations is well known, less work has been done on the case of liquid ionization chambers, where there is still the ne...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/11/2705
更新日期:2014-06-07 00:00:00
abstract::A circular scanning trajectory is and will likely remain a popular choice of trajectory in computed tomography (CT) imaging because it is easy to implement and control. Filtered-backprojection (FBP)-based algorithms have been developed previously for approximate and exact reconstruction of the entire image or a region...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/18/011
更新日期:2004-09-21 00:00:00
abstract::The aim of this study is to investigate the feasibility of using conventional jaws to deliver inverse planned intensity-modulated radiotherapy (IMRT) plans for patients with prostate cancer. For ten patients, each had one three-dimensional conformal plan (3D plan) and seven inverse IMRT plans using direct aperture opt...
journal_title:Physics in medicine and biology
pub_type: 杂志文章,随机对照试验
doi:10.1088/0031-9155/52/8/007
更新日期:2007-04-21 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
pub_type: 杂志文章
doi:10.1088/0031-9155/55/23/S09
更新日期:2010-12-07 00:00:00
abstract::A calibration of the Fricke dosimeter is a measurement of epsilon G(Fe3+). Although G(Fe3+) is expected to be approximately energy independent for all low-LET radiation, existing data are not adequate to rule out the possibility of changes of a few per cent with beam quality. When a high-precision Fricke dosimeter, wh...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/44/7/303
更新日期:1999-07-01 00:00:00
abstract::The reference levels and maximum permissible exposure values for magnetic fields that are currently used have been derived from basic restrictions under the assumption of upright standing body models in a standard posture, i.e. with arms laterally down and without contact with metallic objects. Moreover, if anatomical...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/12/4412
更新日期:2016-06-21 00:00:00
abstract::A photon diffusion model has been developed to calculate the steady-state spatially resolved fluorescence from pencil beam excitation in layered tissue. The model allows the calculation of both the excitation reflectance and the fluorescence escape for an arbitrary continuous depth distribution of tissue optical prope...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/46/2/307
更新日期:2001-02-01 00:00:00
abstract::Elevated interstitial fluid pressure is one of the barriers of drug delivery in solid tumors. Recent studies have shown that normalization of tumor vasculature by anti-angiogenic factors may improve the delivery of conventional cytotoxic drugs, possibly by increasing blood flow, decreasing interstitial fluid pressure,...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/60/4/1477
更新日期:2015-02-21 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
pub_type: 杂志文章
doi:10.1088/0031-9155/52/11/010
更新日期:2007-06-07 00:00:00
abstract::Scattered radiation from within the treatment head can contribute significant dose to all parts of a radiotherapy treatment field. A multileaf collimator may be used to create an arbitrarily shaped field, and may also be used, under dynamic control, to modulate the beam intensity over the field. This method of intensi...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/42/9/006
更新日期:1997-09-01 00:00:00
abstract::The UK, European and IAEA protocols for breast dosimetry in mammography use tabulations of conversion factors, which relate measurements of incident air kerma to the mean glandular dose to the breast. To supplement the existing tabulations, a Monte Carlo computer program has been used to calculate conversion factors f...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/9/2127
更新日期:2014-05-07 00:00:00