Abstract：
:Intravascular brachytherapy requires that the dose be specified within millimeters of the source. High dose gradients near brachytherapy sources require that the source-detector distance be accurately known for dosimetry purposes. Solid phantoms can be designed to accommodate these stringent requirements. This study reports dosimeter readings from 90Sr-90Y sources measured in water, A150, polystyrene and in an epoxy-based water-equivalent plastic. Measurements showed that while A150 and the epoxy-based plastic agreed well with water when the surface of the source contacted the detector housing, the relative response in the phantoms decreased with increasing depth in phantom, falling to approximately 0.55 those of water at a depth of 5 mm. Readings in polystyrene were within 4% of those in water between 1 and 2 mm depth. However, while polystyrene followed water more closely than the other two materials, at greater depths the relative response in polystyrene to water varied from 0.65 to 1.34. When the density of the materials is accounted for, the relative response in A150 is nearly constant with increasing areal density. Furthermore, the response in A150 shows the closest agreement with that in water of any of the solid materials for higher areal densities. For values below 0.3 g/cm2, polystyrene shows the closest agreement with water.
journal_name
Med Physjournal_title
Medical physicsauthors
Buckley LA,Thomadsen BR,DeWerd LAdoi
10.1118/1.1376176subject
Has Abstractpub_date
2001-06-01 00:00:00pages
1010-5issue
6eissn
0094-2405issn
2473-4209journal_volume
28pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract：:A measurement technique previously proposed for determining dose from primary radiation has been tested using 60Co gamma rays. It is shown that the dose from primary radiation is reliably determined for field sizes of 10 X 10 and 20 X 20 cm2 at depths of 0.5, 5, and 10 cm in water. With further development this techni...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596534
更新日期：1990-01-01 00:00:00
abstract：PURPOSE:New technology has been developed to treat age-related macular degeneration (AMD) using 100 kVp pencil-beams that enter the patient through the radio-resistant sclera with a depth of interest between 1.6 and 2.6 cm. Measurement of reference and relative dose in a kilovoltage x-ray beam with a 0.42 cm diameter f...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4863482
更新日期：2014-02-01 00:00:00
abstract：PURPOSE:Primary goal of this study is to select optimal registration schemes in the framework of interstitial lung disease (ILD) follow-up analysis in CT. METHODS:A set of 128 multiresolution schemes composed of multiresolution nonrigid and combinations of rigid and nonrigid registration schemes are evaluated, utilizi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4923170
更新日期：2015-08-01 00:00:00
abstract：:We employed an elastic reservoir filled with tissue-equivalent fluid as an x-ray beam filter for exposure equalization. The filter is designed to be placed between the upper compression plate and the breast. During compression, it will conform to the shape of the peripheral region of the breast and fill the space betw...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596502
更新日期：1990-03-01 00:00:00
abstract：PURPOSE:Currently, in clinical practice of intensity-modulated proton therapy (IMPT), the influence of the minimum monitor unit (MU) constraint is taken into account through postprocessing after the optimization is completed. This may degrade the plan quality and plan robustness. This study aims to mitigate the impact ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12677
更新日期：2018-01-01 00:00:00
abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12854
更新日期：2018-05-01 00:00:00
abstract：:A new type of radiographic film, EDR (extended dose range) film, has been recently become available for film dosimetry. It is particularly attractive for composite isodose verification of intensity modulated radiation therapy because of its low sensitivity relative to the more common Kodak XV film. For XV film, the re...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.1568979
更新日期：2003-05-01 00:00:00
abstract：:Effectiveness of an oral presentation depends on the ability of the speaker to communicate with the audience. An important part of this communication is focusing on two to five key points and emphasizing those points during the presentation. Every aspect of the presentation should be purposeful and directed at facilit...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735944
更新日期：2012-06-01 00:00:00
abstract：:Mammography is the most effective method for breast cancer screening available today. However, the low positive predictive value of breast biopsy resulting from mammogram interpretation leads to approximately 70% unnecessary biopsies with benign outcomes. To reduce the high number of unnecessary breast biopsies, sever...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2786864
更新日期：2007-11-01 00:00:00
abstract：:A 4 x 500 mm2 "cloverleaf" low energy germanium detector array has been assembled for the purpose of in vivo bone lead measurement through x-ray fluorescence. Using 109Cd as an exciting source, results are reported from a leg phantom simulating measurement of lead in a human tibia. For high activity (4.0-4.4 GBq) and ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2436973
更新日期：2007-03-01 00:00:00
abstract：:In proton therapy, it is important to evaluate the field irradiated with protons and the deposited dose distribution in a patient's body. Positron emitters generated through fragmentation reactions of target nuclei can be used for this purpose. By detecting the annihilation gamma rays from the positron emitters, the a...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2712572
更新日期：2007-05-01 00:00:00
abstract：PURPOSE:To investigate how x-ray tube projection angle affects organ and effective doses to patients undergoing a CT examination on a cone beam scanner. METHODS:The authors investigated two cone beam CT systems that use a flat panel detector to capture the x-ray pattern transmitted through patients. One system had the...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3397458
更新日期：2010-05-01 00:00:00
abstract：PURPOSE:The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD). METHODS:Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and exp...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4813906
更新日期：2013-08-01 00:00:00
abstract：PURPOSE:The need for an accurate lesion segmentation tool in 18FDG PET is a prerequisite for the estimation of lesion response to therapy, for radionuclide dosimetry, and for the application of 18FDG PET to radiotherapy planning. In this work, the authors have developed an iterative method based on a mathematical fit d...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3222732
更新日期：2009-10-01 00:00:00
abstract：PURPOSE:This article aims to introduce a novel algorithm for fast beam angle selection in intensity modulated radiotherapy (IMRT). METHODS:The algorithm models the optimization problem as a beam angle ranking problem and chooses suitable beam angles according to their rank. A new parameter called "beam intensity profi...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3517866
更新日期：2010-12-01 00:00:00
abstract：PURPOSE:Examine the use of TomoDose for Tomotherapy quality assurance. METHODS:Baseline TomoDose profiles are acquired annually in accordance with TG-148. During monthly quality assurance, TomoDose is irradiated with a static beam and referenced to baseline. Differences between superimposed profiles are evaluated mont...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735202
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Talbot-Lau x-ray interferometry provides information about the scattering and refractive properties of an object - in addition to the object's attenuation features. Until recently, this method was ineligible for imaging human-sized objects as it is challenging to adapt Talbot-Lau interferometers (TLIs) to the r...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12889
更新日期：2018-06-01 00:00:00
abstract：:The mixed-field dosimetry for 252Cf Applicator Tube (AT) type medical sources available from Oak Ridge National Laboratory (ORNL) has been characterized using ionization chambers, a GM counter, and Monte Carlo methods. Unlike the AAPM Task Group No. 43 (TG-43), specification of dose to muscle instead of water is recom...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.598646
更新日期：1999-08-01 00:00:00
abstract：PURPOSE:To develop a method of using two-dimensional (2D) magnetic resonance thermometry, and three-dimensional (3D) Gaussian modeling to predict the volume, shape, and location of 1 day postoperative T1w high-intensity focused ultrasound lesions in medication refractory tremor patients; thereby facilitating a better c...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.13868
更新日期：2019-12-01 00:00:00
abstract：:A method for finding optimal primary fluence profiles for multiple field external beam radiation therapy techniques has been developed using a radiobiologically based objective function that quantifies the probability of achieving complication-free tumor control, P+. The objective function P+ has the valuable property...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.596971
更新日期：1993-07-01 00:00:00
abstract：PURPOSE:Radiation treatments are trending toward delivering higher doses per fraction under stereotactic radiosurgery and hypofractionated treatment regimens. There is a need for accurate 3D in vivo patient dose verification using electronic portal imaging device (EPID) measurements. This work presents a model-based te...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4935199
更新日期：2015-12-01 00:00:00
abstract：:Respiration can cause tumors in the thorax or abdomen to move by as much as 3 cm; this movement can adversely affect the planning and delivery of radiation treatment. Several techniques have been used to compensate for respiratory motion, but all have shortcomings. Manufacturers of computed tomography (CT) equipment h...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2044427
更新日期：2006-01-01 00:00:00
abstract：PURPOSE:Because the small-radius photon beams shaped by cones in stereotactic radiosurgery (SRS) lack lateral electronic equilibrium and a detector's finite cross section, direct experimental measurement of dosimetric data for these beams can be subject to large uncertainties. As the dose calculation accuracy of a trea...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.3488900
更新日期：2010-10-01 00:00:00
abstract：PURPOSE:Volumetric x-ray microcomputed tomography (CT) can be employed in a variety of quantitative research applications such as image-guided interventions or characterization of medical devices. To ensure the highest geometric fidelity of images for these applications, a phantom and image processing algorithm have be...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4752083
更新日期：2012-10-01 00:00:00
abstract：:Proton therapy offers the potential for excellent dose conformity and reduction in integral dose. The superior dose distribution is, however, much more sensitive to changes in radiological depths along the beam path than for photon fields. Respiratory motion can cause such changes for treatments sites like lung, liver...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.2756602
更新日期：2007-08-01 00:00:00
abstract：PURPOSE:Coronary x-ray computed tomography angiography (CCTA) is used to non-invasively assess coronary artery geometry and has, combined with computational modeling, demonstrated the potential to identify physiologically significant lesions. These measurements require robust and accurate coronary imaging and delineati...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1002/mp.12295
更新日期：2017-07-01 00:00:00
abstract：PURPOSE:To review the issues a physicist may encounter in a community hospital during the transition from film/paper charts to a paperless environment with ARIA and a TrueBeam LINAC. With a lean budget, it was necessary for the physics group to take on the project management responsibilities in order save costs. This w...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4735291
更新日期：2012-06-01 00:00:00
abstract：:Anisotropy of dose distributions around 103Pd, 125I, and 192Ir sources for interstitial brachytherapy was examined. Dose rates around 125I models 6702 and 6711 and 192Ir sources were measured using lithium fluoride thermoluminescence dosimeters (LiF TLDs) in a water-equivalent, solid phantom. From these measured data ...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.597110
更新日期：1993-09-01 00:00:00
abstract：:When an (exposure) calibrated ionization chamber is used for the determination of absorbed dose from a photon beam, the reading of the instrument must be multiplied by a number of factors, one of which is an attenuation correction for phantom material displaced by the chamber. the magnitude of this correction must dep...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.594817
更新日期：1980-11-01 00:00:00
abstract：PURPOSE:Alpha-emitting radionuclides exhibit a potential advantage for cancer treatments because they release large amounts of ionizing energy over a few cell diameters (50-80 μm), causing localized, irreparable double-strand DNA breaks that lead to cell death. Radioimmunotherapy (RIT) approaches using monoclonal antib...
journal_title：Medical physics
pub_type： 杂志文章
doi：10.1118/1.4921997
更新日期：2015-07-01 00:00:00
