Respiration gated radiotherapy treatment: a technical study.

abstract：:In this study we present a three-dimensional (3D) reconstruction algorithm for magneto-acoustic tomography with magnetic induction (MAT-MI) based on the characteristics of the ultrasound transducer. The algorithm is investigated to solve the blur problem of the MAT-MI acoustic source image, which is caused by the ultr...

journal_title：Physics in medicine and biology

authors： Ma R,Zhou X,Zhang S,Yin T,Liu Z

更新日期：2016-12-21 00:00:00

abstract：:The coincidence time resolution (CTR) becomes a key parameter of 511 keV gamma detection in time of flight positron emission tomography (TOF-PET). This is because additional information obtained through timing leads to a better noise suppression and therefore a better signal to noise ratio in the reconstructed image. ...

journal_title：Physics in medicine and biology

authors： Nemallapudi MV,Gundacker S,Lecoq P,Auffray E,Ferri A,Gola A,Piemonte C

更新日期：2015-06-21 00:00:00

abstract：:Refraction contrast of simple objects obtained using diffraction enhanced imaging (DEI) was studied and compared to conventional radiographic contrast. Lucite cylinders and nylon wires were imaged using monochromatic synchrotron radiation at the National Synchrotron Light Source (http://nslsweb. nsls.bnl.gov/nsls/Defa...

journal_title：Physics in medicine and biology

authors： Kiss MZ,Sayers DE,Zhong Z

更新日期：2003-02-07 00:00:00

abstract：:Focused ultrasound (FUS) phased arrays show promise for non-invasive brain therapy. However, the majority of them are limited to a single transmit/receive frequency and therefore lack the versatility to expose and monitor the treatment volume. Multi-frequency arrays could offer variable transmit focal sizes under a fi...

journal_title：Physics in medicine and biology

authors： Deng L,O'Reilly MA,Jones RM,An R,Hynynen K

更新日期：2016-12-21 00:00:00

abstract：:The aim of the study is to verify the fundamental assumption in the monitor source method, i.e. uniform fractional count loss across the field of view (FOV), and to introduce a revised monitor source method for SPECT deadtime correction that minimally interferes with the clinical protocol. SPECT images of non-uniform ...

journal_title：Physics in medicine and biology

authors： Siman W,Silosky M,Kappadath SC

更新日期：2015-02-07 00:00:00

abstract：:Over the last decade, the performance of benchtop x-ray fluorescence computed tomography (XFCT) systems has been significantly enhanced through hardware and software optimizations. Recent studies have indicated the need of energy-resolving pixelated/array detectors in the x-ray detection component to further improve t...

journal_title：Physics in medicine and biology

authors： Moktan H,Ahmed MF,Jayarathna S,Deng L,Cho SH

更新日期：2020-08-31 00:00:00

abstract：:Lung tumors treated in breath-hold are subject to inter- and intra-breath-hold variations, which makes tumor position monitoring during each breath-hold important. A markerless technique is desirable, but limited tumor visibility on kV images makes this challenging. We evaluated if template matching  +  triangulation ...

journal_title：Physics in medicine and biology

authors： Hazelaar C,Dahele M,Mostafavi H,van der Weide L,Slotman B,Verbakel W

更新日期：2018-05-29 00:00:00

abstract：:The effect of the physical state (phase) of the absorbing medium and the energy straggling of the alpha particles on the calculation of the radiation dose due to the daughter products of radon deposited in the lung have been studied in detail. The stopping power data for alpha particles in water and water vapour have ...

journal_title：Physics in medicine and biology

authors： Haque AK,Al-affan IA

更新日期：1987-08-01 00:00:00

abstract：:The most advanced delivery technique for proton radiotherapy is active spot scanning. So far, predominantly static targets have been treated with active spot scanning, since mobile targets in combination with dynamic treatment delivery can lead to interplay effects, causing inhomogeneous dose distributions. One way to...

journal_title：Physics in medicine and biology

authors： Knopf AC,Hong TS,Lomax A

更新日期：2011-11-21 00:00:00

abstract：:A recent paper proposed a novel technique for determining the total body water (TBW) of patients suffering with abnormal hydration levels, using a resonant cavity perturbation method. Current techniques to measure TBW are limited by resolution and technical constraints. However, this new method involves measuring the ...

journal_title：Physics in medicine and biology

authors： Stone DA,Robinson MP

更新日期：2004-05-07 00:00:00

abstract：:Mechanical properties of biological tissues are significant biomarkers for diagnosing various diseases. Assessing the viscoelastic properties of multi-layer tissues has remained challenging for a long time. Some shear wave models have been proposed to estimate thin-layer tissues' viscoelasticity recently. However, the...

journal_title：Physics in medicine and biology

authors： Lu G,Li R,Qian X,Chen R,Jiang L,Chen Z,Shung KK,Humayun MS,Zhou Q

更新日期：2020-11-12 00:00:00

abstract：:DMSA imaging is carried out in nuclear medicine to assess the level of functional renal tissue in patients. This study investigated the use of an artificial neural network to perform diagnostic classification of these scans. Using the radiological report as the gold standard, the network was trained to classify DMSA s...

journal_title：Physics in medicine and biology

authors： Wright JW,Duguid R,McKiddie F,Staff RT

更新日期：2014-04-07 00:00:00

abstract：:The objective in cancer radiotherapy is to maximize tumor-kill while limiting toxic effects of radiation dose on nearby organs-at-risk (OAR). Given a fixed number of treatment sessions, planners thus face the problem of finding a dosing sequence that achieves this goal. This is called the fractionation problem, and ha...

journal_title：Physics in medicine and biology

authors： Ghate A

更新日期：2020-09-16 00:00:00

abstract：:The signal-to-noise ratio (SNR) in x-ray imaging can be increased using a photon counting detector which could allow for rejecting electronics noise and for weighting x-ray photons according to their energies. This approach, however, was not feasible for a long time because photon counting x-ray detectors with very hi...

journal_title：Physics in medicine and biology

authors： Shikhaliev PM

更新日期：2009-08-21 00:00:00

abstract：:By means of the viscoelastodynamic model for a two-layer solid-fluid system and a detailed account of the locally induced acoustic radiation force, a rational analytical and computational framework is established for the viscoelastic characterization of thin tissues from high-frequency ultrasound (HFUS) measurements. ...

journal_title：Physics in medicine and biology

authors： Guzina BB,Tuleubekov K,Liu D,Ebbini ES

更新日期：2009-07-07 00:00:00

abstract：:Dynamic positron emission tomography (PET) imaging can provide information about metabolic changes over time, used for kinetic analysis and auxiliary diagnosis. Existing deep learning-based reconstruction methods have too many trainable parameters and poor generalization, and require mass data to train the neural netw...

journal_title：Physics in medicine and biology

authors： Wang B,Liu H

更新日期：2020-10-13 00:00:00

abstract：:The geometry of a permanent prostate implant varies over time. Seeds can migrate and edema of the prostate affects the position of seeds. Seed movements directly influence dosimetry which relates to treatment quality. We present a method that tracks all individual seeds over time allowing quantification of seed moveme...

journal_title：Physics in medicine and biology

authors： Westendorp H,Nuver TT,Moerland MA,Minken AW

更新日期：2015-10-21 00:00:00

abstract：:In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...

journal_title：Physics in medicine and biology

authors： Palm A,Mattsson O

更新日期：1999-05-01 00:00:00

abstract：:Using Monte Carlo simulation of 99Tcm single-photon-emission computed tomography (SPECT), we investigate the effects of tissue-background activity, tumour location, patient size, uncertainty of energy windows, and definition of tumour region on the accuracy of quantification. The dual-energy-window method of correctio...

journal_title：Physics in medicine and biology

authors： Luo JQ,Koral KF,Ljungberg M,Floyd CE Jr,Jaszczak RJ

更新日期：1995-01-01 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：:Recently, the initial 2D physical characterization of a small-diameter positron emission tomograph, designed specifically for scanning of small laboratory animals, was reported. The physical characteristics of the tomograph operating in 3D mode have now been measured and compared to those obtained in 2D mode. In 3D, t...

journal_title：Physics in medicine and biology

authors： Bloomfield PM,Myers R,Hume SP,Spinks TJ,Lammertsma AA,Jones T

更新日期：1997-02-01 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：:Brain stereotactic radiosurgery (SRS) treatments require multiple quality assurance (QA) procedures to ensure accurate and precise treatment delivery. As single-isocenter multitarget SRS treatments become more popular, the quantification of off-axis accuracy of the linear accelerator is crucial. In this study, a novel...

journal_title：Physics in medicine and biology

authors： Capaldi DPI,Skinner LB,Dubrowski P,Yu AS

更新日期：2020-06-10 00:00:00

abstract：:The advent of real-time ultrasound in the 1970s, together with a growing interest in tissue characterization, led to a number of investigators using the nature of tissue motion to distinguish healthy from diseased tissue. Our group at the (then) Ultrasonics Institute demonstrated the use of phase methods for detecting...

journal_title：Physics in medicine and biology

authors： Wilson LS,Robinson DE,Dadd MJ

更新日期：2000-06-01 00:00:00

abstract：:Successful radiotherapy treatment depends heavily upon the accuracy of patient geometry captured during treatment simulation using computed tomography (CT) scans. Radiotherapy patients are often scanned under free breathing, and respiratory motion can cause severe artifacts in CT scans, including shortening, elongatio...

journal_title：Physics in medicine and biology

authors： Lewis JH,Jiang SB

更新日期：2009-02-07 00:00:00

abstract：:Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contras...

journal_title：Physics in medicine and biology

authors： Tsai CH,Zhang JW,Liao YY,Liu HL

更新日期：2016-04-07 00:00:00

abstract：:Droplets of liquid perfluorocarbon (PFC) are under study as the next generation of contrast agents for ultrasound (US). These droplets can be selectively vaporized into echogenic gas bubbles in situ by externally applied US, with numerous applications to diagnosis and therapy. However, little is known about the mechan...

journal_title：Physics in medicine and biology

authors： Reznik N,Seo M,Williams R,Bolewska-Pedyczak E,Lee M,Matsuura N,Gariepy J,Foster FS,Burns PN

更新日期：2012-11-07 00:00:00

abstract：:Tumour histological grade has prognostic implications in breast cancer. Tumour features in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and T2-weighted (T2W) imaging can provide related and complementary information in the analysis of breast lesions to improve MRI-based histological status prediction...

journal_title：Physics in medicine and biology

authors： Fan M,Liu Z,Xie S,Xu M,Wang S,Gao X,Li L

更新日期：2019-10-23 00:00:00

abstract：:As a new method, x-ray diffraction enhanced imaging (DEI) has extremely high sensitivity for weakly absorbing low-Z samples in medical and biological fields. Conventional performance parameters, such as spatial resolution and low-contrast resolution, are not enough to describe the characteristics of a DEI system. This...

journal_title：Physics in medicine and biology

authors： Huang ZF,Kang KJ,Li Z

更新日期：2006-06-21 00:00:00

abstract：:An ESTRO booklet and a report of the Netherlands Commission on Radiation Dosimetry have been published recently describing empirical methods for monitor unit (MU) calculations in symmetrical high-energy photon beams. Both documents support the same basic ideas; firstly the separation of head scatter and volume scatter...

journal_title：Physics in medicine and biology

authors： Georg D

更新日期：1999-12-01 00:00:00