Abstract：
:Over the past few years there has been much interest in the development of three-dimensional dosimeters to determine the complex absorbed dose distribution in modern radiotherapy techniques such as IMRT and IGRT. In routine methods used for three-dimensional dosimetry, polymer gels are commonly used. Recently, a novel transparent polymer dosimeter, known as PRESAGE, has been introduced in which a radiochromic color change is observed upon radiation. PRESAGE has some advantages over usual polymer gel dosimeters. It has been noted that the sensitivity of PRESAGE can be changed when different amounts of the components are used for its fabrication. This study has focused on the assessment of dosimetric characteristics of PRESAGE for various amounts of components in its formulation. To achieve this, PRESAGE dosimeters were fabricated using various amounts of their constituting components. Then the dosimeters were irradiated to (60)Co gamma photons for a range of radiation doses from 0 to 50 Gy. Consequently, the light absorption changes of the dosimeters were measured by a spectrophotometer at different post-irradiation time periods. It was generally observed that as the concentration of the radical initiator is increased, the PRESAGE dosimeter sensitivity is increased while its stability is decreased. Furthermore, it was noted that with the high concentration of the radical initiator and leuco dye, the sensitivity of PRESAGE is decreased.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Mostaar A,Hashemi B,Zahmatkesh MH,Aghamiri SM,Mahdavi SRdoi
10.1088/0031-9155/55/3/023subject
Has Abstractpub_date
2010-02-07 00:00:00pages
903-12issue
3eissn
0031-9155issn
1361-6560pii
S0031-9155(10)28599-8journal_volume
55pub_type
杂志文章abstract：:Dynamic SPECT is a relatively new technique that may potentially benefit many imaging applications. Though similar to dynamic PET, the accuracy and precision of dynamic SPECT parameter estimates are degraded by factors that differ from those encountered in PET. In this work we formulate a methodology for analytically ...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/44/8/311
更新日期：1999-08-01 00:00:00
abstract：:The goal of this study is to demonstrate the feasibility of a novel non-coplanar-arc optimization algorithm (CyberArc). This method aims to reduce the delivery time of conventional CyberKnife treatments by allowing for continuous beam delivery. CyberArc uses a 4 step optimization strategy, in which nodes, beams, and c...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/aa6f92
更新日期：2017-06-26 00:00:00
abstract：:We experimentally investigated the SPECT recovery of I-131 activity in multiple spheres located simultaneously at different locations within a cylindrical phantom that had an elliptical cross section. The sphere volumes ranged from 209 cc down to 4.2 cc. A Prism 3000 camera and two types of parallel-hexagonal-hole col...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/52/3/017
更新日期：2007-02-07 00:00:00
abstract：:The 50-year tenure of Physics in Medicine and Biology has coincided with some of the most important developments in radiological science, including the introduction of artificial radioactivity, computers and 3D imaging into medicine. These events have profoundly influenced the development of brachytherapy. Although it...
journal_title：Physics in medicine and biology
pub_type： 杂志文章,评审
doi：10.1088/0031-9155/51/13/R18
更新日期：2006-07-07 00:00:00
abstract：:In this paper we describe a method for quantitative photoacoustic tomography (qPAT) based on the photon radiative transfer equation (RTE) coupled with the Helmholtz photoacoustic wave equation. Considerable simulations and tissue-like phantom experiments are conducted to evaluate transport-based qPAT in comparison wit...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/55/7/009
更新日期：2010-04-07 00:00:00
abstract：:Multileaf collimators (MLCs) have been in clinical use for many years and meanwhile are commonly used to deliver intensity-modulated radiotherapy (IMRT) beams. For this purpose it is important to know their dosimetric properties precisely, one of them being inter- and intraleaf leakage. The Siemens 160 MLC features a ...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/56/2/N02
更新日期：2011-01-21 00:00:00
abstract：:A new method for correcting simultaneously the attenuation, scatter and resolution effects in SPECT has been developed for the case of a homogeneous medium. It is based on an effective model of the scatter process. This model depends on only four parameters which are determined experimentally and remain independent of...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/39/4/005
更新日期：1994-04-01 00:00:00
abstract：:We used a real-skull phantom head to investigate the performances of representative methods for EEG source localization when considering various head models. We describe several experiments using a montage with current sources located at multiple positions and orientations inside a human skull filled with a conductive...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/46/1/306
更新日期：2001-01-01 00:00:00
abstract：:We have investigated the tongue-and-groove effect on the IMRT dose distributions for a Varian MLC. We have compared the dose distributions calculated using the intensity maps with and without the tongue-and-groove effect. Our results showed that, for one intensity-modulated treatment field, the maximum tongue-and-groo...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/46/4/310
更新日期：2001-04-01 00:00:00
abstract：:The radiofrequency dielectric behaviour of packed human erythrocytes has been investigated in normal haemoglobins F and AA and also abnormal haemoglobins homozygous SS and heterozygous AS. Dielectric measurements were made in tightly packed blood cells at an average room temperature of 26.5 +/- 0.5 degrees C in the fr...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/28/4/002
更新日期：1983-04-01 00:00:00
abstract：:In treatment planning we depend upon accurate knowledge of geometric and range uncertainties. If the uncertainty model is inaccurate then the plan will produce under-dosing of the target and/or overdosing of OAR. We aim to provide a method for which centre and site-specific population range uncertainty due to inter-fr...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/aa9502
更新日期：2017-12-19 00:00:00
abstract：:The aim of this study was to systematically investigate the influence of the inter- and intra-observer segmentation variation of tumors and organs at risk on the simulated temperature coverage of the target. CT scans of six patients with tumors in the pelvic region acquired for radiotherapy treatment planning were use...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/aa685b
更新日期：2017-05-08 00:00:00
abstract：:Online adaptive radiation therapy (ART) based on real-time magnetic resonance imaging represents a paradigm-changing treatment scheme. However, conventional quality assurance (QA) methods based on phantom measurements are not feasible with the patient on the treatment couch. The purpose of this work is to develop a fa...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/aa6e38
更新日期：2017-06-21 00:00:00
abstract：:Compton scatter poses a significant threat to volumetric x-ray computed tomography, bringing cupping and streak artefacts thus impacting qualitative and quantitative imaging procedures. To perform appropriate scatter compensation, it is necessary to estimate the magnitude and spatial distribution of x-ray scatter. The...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/55/8/010
更新日期：2010-04-21 00:00:00
abstract：:A recently described, computer aided method of attenuation analysis has been applied to free-air chamber measurements of the attenuation by up to 30mm A1 of the exposure rate of a narrow beam of X-radiation excited at a thick W target in a Be window tube by constant potentials of 60, 80, 100, 120 and 140 kV. It has ...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/22/2/001
更新日期：1977-03-01 00:00:00
abstract：:The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/60/10/n209
更新日期：2015-05-21 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：:By the end of 2002, 33 398 patients worldwide had been treated with proton radiotherapy, 10 829 for eye diseases. The dose prediction algorithms used today for ocular proton therapy treatment planning rely on parameterizations of measured proton dose distributions, i.e., broad-beam and pencil-beam techniques, whose pr...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/50/22/002
更新日期：2005-11-21 00:00:00
abstract：:Several studies have been appeared, up to now, that indicate the effect of accurate simulation on dose received by different substructures of the eye, irradiated by external beams of short-range radiation such as electron. Different representations of the eye have consequently been introduced. Their accuracies depend ...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/ab2059
更新日期：2019-07-02 00:00:00
abstract：:The dosimetric impact of intrafraction prostate motion was investigated for helical tomotherapy treatments. Measured motion tracks were used to calculate the dosimetric impact on delivered target dose distributions. A dynamic dose calculation engine was developed to facilitate this evaluation. It was found that the D9...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/53/24/005
更新日期：2008-12-21 00:00:00
abstract：:As the use of radiofrequency (RF) electromagnetic (EM) fields has increased along with increased use of wireless communication, the possible related health risks have also been widely discussed. One safety aspect is the interaction of medical implants and RF devices like mobile phones. In the literature, effects on ac...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/52/5/001
更新日期：2007-03-07 00:00:00
abstract：:The widely applied single-interaction analytic expression characterizing the energy resolution component of the angular resolution precision for an electronically collimated point source is extended to include multiple-interaction Compton scatter sequences as well as sequences terminated by photoelectric absorption. T...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/43/10/021
更新日期：1998-10-01 00:00:00
abstract：:Although physical metrics can objectively characterize computed tomography (CT) image quality, quantitative approaches to predict human observer performance are more accurate and clinically relevant. This study compared a modified channelized Hotelling model observer (CHO) with human observers in a shape discriminatio...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/59/13/3389
更新日期：2014-07-07 00:00:00
abstract：:The interest in positron emission tomography (PET) and particularly in hybrid integrated PET/CT systems has significantly increased in the last few years due to the improved quality of the obtained images. Nevertheless, one of the most important limits of the PET imaging technique is still its poor spatial resolution ...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/55/14/012
更新日期：2010-07-21 00:00:00
abstract：:Many applications of electroporation, especially those utilizing electrofusion and in-vivo electroporation, involve cell environments that include close cell-to-cell proximity and a wide range of target cell size. It is important to understand how this kind of environment may alter optimum electroporation electrical p...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/51/12/012
更新日期：2006-06-21 00:00:00
abstract：:The aim of this study was to investigate the utility of consistency metrics, such as inverse consistency, in contour-based deformable registration error analysis. Four images were acquired of the same phantom that has experienced varying levels of deformation. The deformations were simulated with deformable image regi...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/54/18/014
更新日期：2009-09-21 00:00:00
abstract：:We have developed a model using Monte Carlo methods to simulate x-ray mammography. All possible physical processes of interaction of x-rays with matter have been taken into account. A simplified geometry of the mammographic apparatus has been considered along with a software phantom of compressed breast. The phantom m...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/43/11/012
更新日期：1998-11-01 00:00:00
abstract：:We find the dose distribution that maximizes the tumour control probability (TCP) for a fixed mean tumour dose per fraction. We consider a heterogeneous tumour volume having a radiation response characterized by the linear quadratic model with heterogeneous radiosensitivity and repopulation rate that may vary in time....
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/49/3/005
更新日期：2004-02-07 00:00:00
abstract：:This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computa...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/52/21/003
更新日期：2007-11-07 00:00:00
abstract：:The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discu...
journal_title：Physics in medicine and biology
pub_type： 杂志文章,评审
doi：10.1088/0031-9155/60/2/R1
更新日期：2015-01-21 00:00:00
