Abstract:
:The energy dependence of the luminance ratio due to scattered and primary radiation has been determined for four types of X-ray intensifying screens. A water phantom of 30 cm X 30 cm X 20 cm was used as the scattering medium. Ten narrow band X-ray spectra were used as incident radiation: the mean energies of these spectra ranged from 28 to 84 keV. Using the monoenergetic data, results were calculated for broad spectra and compared with measured results for broad spectra. For tube voltages up to 50 kV the calculated results agreed well with the measured results: for higher tube voltages a small difference occurred.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Koedooder K,Venema HWdoi
10.1088/0031-9155/29/10/007subject
Has Abstractpub_date
1984-10-01 00:00:00pages
1237-48issue
10eissn
0031-9155issn
1361-6560journal_volume
29pub_type
杂志文章abstract::With the development of laser technology, laser-driven proton acceleration provides a new method for proton tumor therapy. However, it has not been applied in practice because of the wide and decreasing energy spectrum of laser-accelerated proton beams. In this paper, we propose an analytical model to reconstruct the ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa6fce
更新日期:2017-07-07 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
pub_type: 杂志文章
doi:10.1088/1361-6560/ab4c0d
更新日期:2019-11-21 00:00:00
abstract::In recent years, particle therapy has become a widely accepted form of cancer treatment and technological advances in beam delivery technology (i.e. pencil beam scanning (PBS)) have enabled the application of highly conformal dose distributions to static targets. Current research focuses on the possibilities for the t...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/22/7905
更新日期:2013-11-21 00:00:00
abstract::The dose-calculation accuracy of the tomotherapy Hi-Art II(R) (Tomotherapy, Inc., Madison, WI) treatment planning system (TPS) in the presence of low-density lung media was investigated. In this evaluation, a custom-designed heterogeneous phantom mimicking the mediastinum geometry was used. Gammex LN300 and balsa wood...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/8/004
更新日期:2009-04-21 00:00:00
abstract::Spinal screw placement is a challenging task due to small bone corridors and high risk of neurological or vascular complications, benefiting from precision guidance/navigation and quality assurance (QA). Implicit to both guidance and QA is the definition of a surgical plan-i.e. the desired trajectories and device sele...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5f42
更新日期:2017-04-07 00:00:00
abstract::Ultrasound-based elastography including strain elastography, acoustic radiation force impulse (ARFI) imaging, point shear wave elastography and supersonic shear imaging (SSI) have been used to differentiate breast tumors among other clinical applications. The objective of this study is to extend a previously published...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa58c9
更新日期:2017-03-07 00:00:00
abstract::This work presents an improvement of the VIPARnd ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composit...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa5089
更新日期:2017-02-07 00:00:00
abstract::Recent acute shortage of medical radioisotopes prompted investigations into alternative methods of production and the use of a cyclotron and ¹⁰⁰Mo(p,2n)(99m)Tc reaction has been considered. In this context, the production yields of (99m)Tc and various other radioactive and stable isotopes which will be created in the ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/56/17/002
更新日期:2011-09-07 00:00:00
abstract::Magnetic resonance imaging (MRI) may be used to image three-dimensional dose distributions of ionizing radiation in tissue equivalent gels infused with ferrous sulphate solutions, commonly known as Fricke gels. In this technique, ferrous (Fe2+) ions are oxidized to ferric (Fe3+) ions by free radicals produced by ioniz...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/9/013
更新日期:1996-09-01 00:00:00
abstract::Recent studies of the minute morphology of the skin by optical coherence tomography revealed that the sweat ducts in human skin are helically shaped tubes, filled with a conductive aqueous solution. This, together with the fact that the dielectric permittivity of the dermis is higher than that of the epidermis, brings...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/54/11/005
更新日期:2009-06-07 00:00:00
abstract::In carbon-ion radiotherapy, single-beam delivery each day in alternate directions has been common practice for efficient operation, taking advantage of the Bragg peak and the relative biological effectiveness (RBE) for uniform dose conformation to a tumor. Treatments are usually fractionated and treatment plans are ev...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/62/3/1062
更新日期:2017-02-07 00:00:00
abstract::EEG interictal epileptiform discharges in temporal lobe epilepsy are associated with magnetic fields. The maxima of magnetic spikes recorded over the spherical portions of the head appear fairly symmetric, whereas those over the lower temporal region often have irregular shapes. Furthermore, their magnitude is often u...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/32/1/009
更新日期:1987-01-01 00:00:00
abstract::The stochastic nature of cavitation implies visualization of the cavitation cloud in real-time and in a discriminative manner for the safe use of focused ultrasound therapy. This visualization is sometimes possible with standard echography, but it strongly depends on the quality of the scanner, and is hindered by diff...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa4fe8
更新日期:2017-02-07 00:00:00
abstract::Ultraviolet (UV) treatment dose is determined by the length of time that a patient spends in a phototherapy cabin. The output from UV fluorescent lamps declines with use and a method is needed to compensate for the change in irradiance and to identify and replace any lamps that fail. The decline in lamp output with ag...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/51/2/008
更新日期:2006-01-21 00:00:00
abstract::Compact gamma cameras with a square-shaped monolithic scintillator crystal and an array of silicon photomultipliers (SiPMs) are actively being developed for applications in areas such as small animal imaging, cancer diagnostics and radiotracer guided surgery. Statistical methods of position reconstruction, which are p...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aa6029
更新日期:2017-05-07 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::Poly(vinyl alcohol) cryogel, PVA-C, is presented as a tissue-mimicking material, suitable for application in magnetic resonance (MR) imaging and ultrasound imaging. A 10% by weight poly(vinyl alcohol) in water solution was used to form PVA-C, which is solidified through a freeze-thaw process. The number of freeze-thaw...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/49/24/009
更新日期:2004-12-21 00:00:00
abstract::We extend the theory of three-dimensional (3D) tomographic intensity modulated radiation therapy (IMRT). The geometry consists of two-dimensional modulated beams on a sphere centred in the tumour. The theory provides an efficient algorithm for computing beam modulation patterns that approximately 'reconstruct' the pre...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/47/5/306
更新日期:2002-03-07 00:00:00
abstract::We present a new version of STIR (Software for Tomographic Image Reconstruction), an open source object-oriented library implemented in C++ for 3D positron emission tomography reconstruction. This library has been designed such that it can be used for many algorithms and scanner geometries, while being portable to var...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/57/4/867
更新日期:2012-02-21 00:00:00
abstract::Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and child...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0022-3727/59/21/6355
更新日期:2014-11-07 00:00:00
abstract::Component-based normalization is a method used to compensate for the sensitivity of each of the lines of response acquired in positron emission tomography. This method consists of modelling the sensitivity of each line of response as a product of multiple factors, which can be classified as time-invariant, time-varian...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/61/9/3554
更新日期:2016-05-07 00:00:00
abstract::An original method for the analysis of oscillations of cutaneous blood flow has been developed, which makes use of laser Doppler flowmetry (LDF) data and is based on the continuous wavelet transform and adaptive wavelet theory. The potential of the method has been demonstrated in experiments with the response of micro...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/53/21/005
更新日期:2008-11-07 00:00:00
abstract::The measured attenuation correction technique is widely used in cardiac positron tomographic studies. However, the success of this technique is limited because of insufficient counting statistics achievable in practical transmission scan times, and of the scattered radiation in transmission measurement which leads to ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/10/024
更新日期:1996-10-01 00:00:00
abstract::Monte Carlo simulations were used to investigate large-angle x-ray scatter at design energy of 25 keV during small field of view (9.6 cm × 5 cm) differential phase contrast imaging of the breast using Talbot-Lau interferometry. Homogenous, adipose and fibroglandular breasts of uniform thickness ranging from 2 to 8 cm ...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/59/21/6387
更新日期:2014-11-07 00:00:00
abstract::Automatic cell cycle analysis (DNA histograms) is usually performed with flow cytometry. In cases when only few cells are available, the DNA content has to be measured with a fluorescence microscope combined with sensitive camera systems (SIT, MCP, cooled CCDs) and a frame grabber for image analysis. The fluorescent c...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/41/3/013
更新日期:1996-03-01 00:00:00
abstract::Energy and angular distributions of electron beams with different energies were simulated by Monte Carlo calculations. These beams were generated by the NOVAC7 system (Hitesys, Italy), a mobile electron accelerator specifically dedicated to intra-operative radiation therapy (IORT). The electron beam simulations were v...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/52/20/008
更新日期:2007-10-21 00:00:00
abstract::Mean glandular dose (MGD) is the figure of merit to assess breast dose after a mammographic acquisition. The use of normalized MGD obtained from Monte Carlo computations with measured incident air kerma determines the MGD delivered to patients. The Geant4 Application for Tomographic Emission (GATE) toolkit is a modern...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/0031-9155/58/7/2247
更新日期:2013-04-07 00:00:00
abstract::As automation in radiation oncology becomes more common, it is important to determine which algorithms are equivalent for a given workflow. Often, algorithm comparisons are performed in isolation; however, clinical context can provide valuable insight into the importance of algorithm features and error magnification i...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/ab9fc8
更新日期:2020-09-28 00:00:00
abstract::Quantitative assessment of mammographic asymmetry has been investigated for breast cancer risk prediction. A new asymmetry feature extraction method was proposed in this study to enhance the risk prediction accuracy of near-term breast cancer. Breast areas in each pair of bilateral mammographic images were divided int...
journal_title:Physics in medicine and biology
pub_type: 杂志文章
doi:10.1088/1361-6560/aae452
更新日期:2018-10-17 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