Estimation of renal scintigraphy parameters using a linear piecewise-continuous model.

abstract：:A reader study was conducted to tune the parameters of an observer model used to predict the detectability index (dʹ ) of test objects as a task-based quality control (QC) metric for digital mammography. A simple test phantom was imaged to measure the model parameters, namely, noise power spectrum,modulation transfer ...

journal_title：Physics in medicine and biology

authors： Bloomquist AK,Mainprize JG,Mawdsley GE,Yaffe MJ

更新日期：2014-11-07 00:00:00

abstract：:This paper presents a Fourier rebinning algorithm for three-dimensional image reconstruction in PET that incorporates the concept of spectral transfer function. It suggests the need for discarding low-frequency components in the rebinning. It also includes the correction for rebinning efficiency which was evaluated by...

journal_title：Physics in medicine and biology

authors： Tanaka E,Amo Y

更新日期：1998-04-01 00:00:00

abstract：:Simultaneous rest perfusion/fatty-acid metabolism studies have the potential to replace sequential rest/stress perfusion studies for the assessment of cardiac function. Simultaneous acquisition has the benefits of increased signal and lack of need for patient stress, but is complicated by cross-talk between the two ra...

journal_title：Physics in medicine and biology

authors： Trott CM,Ouyang J,El Fakhri G

更新日期：2010-11-21 00:00:00

abstract：:Two dosimetry protocols based on absorbed dose to water have recently been implemented: TG-51 and TRS-398. These protocols use different beam-quality indices: %dd(10)x and TPR20,10. The effect of electron contamination in measurements of %dd(10)x has been proposed as a disadvantage of the TG-51. For actual measurement...

journal_title：Physics in medicine and biology

authors： Lopez Medina A,Teijeiro A,Salvador F,Medal D,Vazquez J,Salgado M,Carrion MC

更新日期：2004-01-07 00:00:00

abstract：:The reproducibility of polyacrylamide gel (PAG) dosimetry has been evaluated when used to verify two radiotherapy treatment plans of increasing complexity. The plans investigated were a three-field coplanar arrangement, using the linac jaws for field shaping, and a four-field, conformal, non-coplanar plan using precis...

journal_title：Physics in medicine and biology

authors： Cosgrove VP,Murphy PS,McJury M,Adams EJ,Warrington AP,Leach MO,Webb S

更新日期：2000-05-01 00:00:00

abstract：:Ion chamber dosimetry requires a high degree of precision, at all steps within the dosimetric process, in order to ensure accurate dose measurements. This work presents a novel technique for ion chamber volume determination and quality assurance, using micro-computed tomography (micro-CT). Four nominally identical Exr...

journal_title：Physics in medicine and biology

authors： McNiven AL,Umoh J,Kron T,Holdsworth DW,Battista JJ

更新日期：2008-09-21 00:00:00

abstract：:Using Cherenkov radiation in positron emission tomography (PET) has the potential to improve the time of flight (TOF) resolution and reduce the cost of detectors. In previous studies promising TOF results were achieved when lead fluoride (PbF2) crystals were used instead of a scintillator. In this work, a whole-body P...

journal_title：Physics in medicine and biology

authors： Consuegra D,Korpar S,Križan P,Pestotnik R,Razdevšek G,Dolenec R

更新日期：2020-03-06 00:00:00

abstract：:Andreo and Benmakhlouf (2017 Phys. Med. Biol. 62 1518-32) have disputed a finding of Scott et al (2012 Phys. Med. Biol. 57 4461-76) that the variation with field-size of the response of small ion chambers and solid-state dosimeters in small megavoltage photon radiation fields can largely be attributed to density. Furt...

journal_title：Physics in medicine and biology

authors： Fenwick JD,Georgiou G,Rowbottom CG,Underwood TSA,Kumar S

更新日期：2018-10-03 00:00:00

abstract：:Large blood vessels can produce steep temperature gradients in heated tissues leading to inadequate tissue temperatures during hyperthermia. This paper utilizes a finite difference scheme to solve the basic equations of heat transfer and fluid flow to model blood vessel cooling. Unlike previous formulations, heat tran...

journal_title：Physics in medicine and biology

authors： Kolios MC,Sherar MD,Hunt JW

更新日期：1995-04-01 00:00:00

abstract：:Previous treatment of cerebrospinal fluid (CSF) malignancies by intrathecal administration of (131)I-radiolabelled monoclonal antibodies has led to the assumption that more healthy tissue will be spared when a pure beta-emitter such as (90)Y replaces (131)I. The purpose of this study is to compare and quantitatively e...

journal_title：Physics in medicine and biology

authors： Mardirossian G,Hall M,Montebello J,Stevens P

更新日期：2006-01-07 00:00:00

abstract：:In stereotactic radiosurgery, a seven-irradiation film was used to define any discrepancy between the beam and target centres. A mathematical model based on the linac alignment and target set-up was developed to diagnose the discrepancies of the seven-irradiation film between the beam and simulation target centres. Fr...

journal_title：Physics in medicine and biology

authors： Tsai JS

更新日期：1996-09-01 00:00:00

abstract：:Gas target systems have been used for decades on cyclotrons to produce radionuclides for medical imaging. However, the activity recovered from such targets is often lower than its theoretically predicted value. Past research has suggested that nuclide interactions with the walls of the target body may play a key role ...

journal_title：Physics in medicine and biology

authors： Zacchia NA,Buckley KR,Martinez GM,Ruth TJ,Martinez DM,Hoehr C

更新日期：2018-09-28 00:00:00

abstract：:This work aims to contribute to the study of the radiation dose distribution delivered to the hands of medical staff members during a general computed tomographic (CT) fluoroscopic guided procedure. In this study, both Monte Carlo simulations and measurements were performed. For free-in-air and computed tomography dos...

journal_title：Physics in medicine and biology

authors： Figueira C,Becker F,Blunck C,DiMaria S,Baptista M,Esteves B,Paulo G,Santos J,Teles P,Vaz P

更新日期：2013-08-21 00:00:00

abstract：:In medical imaging different techniques have been developed to gain information from inside a tissue. Optoacoustics is a method to generate tomography pictures of tissue using Q-switched laser pulses. Due to thermal and pressure confinement, a short light pulse generates a pressure distribution inside tissue, which mi...

journal_title：Physics in medicine and biology

authors： Köstli KP,Frenz M,Bebie H,Weber HP

更新日期：2001-07-01 00:00:00

abstract：:A new multiplicative correction factor for tissue heterogeneities based on an exact expression for homogeneous non-unit-density media is proposed. O'Connor's density scaling theorem is invoked to evaluate the medium-specific tissue-maximum ratios used in the exact formulation. Monte Carlo calculations were performed a...

journal_title：Physics in medicine and biology

authors： Petti PL,Siddon RL,Bjärngard BE

更新日期：1986-10-01 00:00:00

abstract：:Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issu...

journal_title：Physics in medicine and biology

authors： Bera D,Raghunathan SB,Chen C,Chen Z,Pertijs MAP,Verweij MD,Daeichin V,Vos HJ,van der Steen AFW,de Jong N,Bosch JG

更新日期：2018-03-29 00:00:00

abstract：:Optical computed tomography (optical-CT) of 3D radiation dosimeters is a promising avenue for delivering an economic and reliable quality control of radiotherapy treatments such as intensity modulated radiotherapy, brachytherapy and stereotactic radiosurgery. The main problems in transferring 3D dosimeters to clinical...

journal_title：Physics in medicine and biology

authors： Krstajić N,Doran SJ

更新日期：2007-06-07 00:00:00

abstract：:A silicon semiconductor photodiode was used to measure the TL-signal of TLD-300 (CaF2:Tm) detectors irradiated with 60Co gamma rays and 226Ra alpha particles. The applied dose values varied from 0.12 to 14.3 Gy for gamma rays and from about 50 to 300 Gy for alpha particles. Because of the infrared sensitivity of the p...

journal_title：Physics in medicine and biology

authors： Meissner P,Jacob M,Rassow J

更新日期：1988-12-01 00:00:00

abstract：:Ultrasonic speed of propagation and attenuation were investigated as a function of absorbed radiation dose in PAG and MAGIC polymer gel dosimeters. Both PAG and MAGIC gel dosimeters displayed a dependence of ultrasonic parameters on absorbed dose with attenuation displaying significant changes in the dose range invest...

journal_title：Physics in medicine and biology

authors： Mather ML,De Deene Y,Whittaker AK,Simon GP,Rutgers R,Baldock C

更新日期：2002-12-21 00:00:00

abstract：:A Geiger-mode avalanche photodiode (Si-PM) is a promising photodetector for PET, especially for use in a magnetic resonance imaging (MRI) system, because it has high gain and is less sensitive to a static magnetic field. We developed a Si-PM-based depth-of-interaction (DOI) PET system for small animals. Hamamatsu 4 × ...

journal_title：Physics in medicine and biology

authors： Yamamoto S,Imaizumi M,Watabe T,Watabe H,Kanai Y,Shimosegawa E,Hatazawa J

更新日期：2010-10-07 00:00:00

abstract：:A Monte Carlo computer program has been developed for the computation of integral radiation dose to the breast in xeromammography. The results are given in terms of the integral dose per unit area of the breast per unit incident exposure. The calculations have been made for monoenergetic incident photons and the resul...

journal_title：Physics in medicine and biology

authors： Dance DR

更新日期：1980-01-01 00:00:00

abstract：:A method using both patient geometric and dosimetric information was proposed to predict dose-volume histograms (DVHs) of organs at risk (OARs) for a nasopharyngeal cancer (NPC) intensity-modulated radiation therapy (IMRT) plan. A total of 106 nine-field IMRT NPC plans were used in this study. Twenty-six plans were ra...

journal_title：Physics in medicine and biology

authors： Jiao SX,Chen LX,Zhu JH,Wang ML,Liu XW

更新日期：2019-12-05 00:00:00

abstract：:This paper describes the development and characterization of a fully automated in vitro cell irradiator using an electronic brachytherapy source to perform radiation sensitivity bioassays. This novel irradiator allows complex variable dose and dose rate schemes to be delivered to multiple wells of 96-well culture plat...

journal_title：Physics in medicine and biology

authors： Fowler TL,Fulkerson RK,Micka JA,Kimple RJ,Bednarz BP

更新日期：2014-03-21 00:00:00

abstract：:Ion beam therapy offers the possibility of a highly conformal tumor-dose distribution; however, this technique is extremely sensitive to inaccuracies in the treatment procedures. Ambiguities in the conversion of Hounsfield units of the treatment planning x-ray CT to relative stopping power (RSP) can cause uncertaintie...

journal_title：Physics in medicine and biology

authors： Meyer S,Gianoli C,Magallanes L,Kopp B,Tessonnier T,Landry G,Dedes G,Voss B,Parodi K

更新日期：2017-02-07 00:00:00

abstract：:Tumour blood flow is one of the important factors limiting the efficacy of radiation therapy (hypoxic radioresistance), chemotherapy (drug delivery) and thermal therapy (heat dissipation) in treating cancer. The modification of tumour blood flow has been an area of intense investigation. In the current study, the arte...

journal_title：Physics in medicine and biology

authors： Purdie TG,Lee TY

更新日期：2003-04-07 00:00:00

abstract：:Two complementary approaches to the noise suppression problem in on-line portal imaging have been analysed. Temporal filtering by image summation can substantially reduce the amount of noise in an image. In many cases, however, movements of the patient or the radiation source limit the time period over which the avera...

journal_title：Physics in medicine and biology

authors： Leszczynski KW,Shalev S,Cosby NS

更新日期：1990-03-01 00:00:00

abstract：:Electrical properties (EP), namely conductivity and permittivity, can provide endogenous contrast for tissue characterization. Using electrical property tomography (EPT), maps of EP can be generated from conventional MRI data. This report investigates the feasibility and accuracy of EPT at 21.1 T for multiple RF coils...

journal_title：Physics in medicine and biology

authors： Amouzandeh G,Mentink-Vigier F,Helsper S,Bagdasarian FA,Rosenberg JT,Grant SC

更新日期：2020-02-28 00:00:00

abstract：:A three-dimensional (3D) point-kernel multiple scatter model for point spread function (PSF) determination in parallel-beam single-photon emission computed tomography (SPECT), based on a dose gamma-ray buildup factor, is proposed. This model embraces nonuniform attenuation in a voxelized object of imaging (patient bod...

journal_title：Physics in medicine and biology

authors： Marinkovic P,Ilic R,Spaic R

更新日期：2007-10-07 00:00:00

abstract：:In (19)F MRI oximetry, a method used to image tumour hypoxia, perfluorocarbons serve as oxygenation markers. The goal of this study is to evaluate the impact of perfluorocarbon distribution and concentration in (19)F MRI oximetry through a computer simulation. The simulation studies the correspondence between (19)F me...

journal_title：Physics in medicine and biology

authors： Baete SH,Vandecasteele J,De Deene Y

更新日期：2011-04-21 00:00:00

abstract：:The influence of artefacts due to metal implants on the range of ion beams is investigated, using a geometrically well-defined head and pelvic phantom together with inserts from steel, titanium and tungsten. The ranges along various beam paths including artefacts were calculated from the TPS and compared to known calc...

journal_title：Physics in medicine and biology

authors： Jäkel O,Reiss P

更新日期：2007-02-07 00:00:00