Measurement of flow velocity fields in small vessel-mimic phantoms and vessels of small animals using micro ultrasonic particle image velocimetry (micro-EPIV).

abstract：:An efficient registration strategy is described that aims to help solve delicate medical imaging registration problems. It consists of running several registration methods for each dataset and selecting the best one for each specific dataset, according to an evaluation criterion. Finally, the quality of the registrati...

journal_title：Physics in medicine and biology

authors： Tacchella JM,Roullot E,Lefort M,Cohen ME,Guillevin R,Petrirena G,Delattre JY,Habert MO,Yeni N,Kas A,Frouin F

更新日期：2014-11-21 00:00:00

abstract：:Two new detectors (0.015 cm3 ion chamber from PTW, 0.6 mm diameter diode from Scanditronix AB) designed specifically for use in small stereotactic fields were compared against similar, more routine, detectors (0.125 cm3 ion chamber, parallel plate chamber, shielded and unshielded diodes and film). Percentage depth dos...

journal_title：Physics in medicine and biology

authors： McKerracher C,Thwaites DI

更新日期：1999-09-01 00:00:00

abstract：:We model the heterogeneous response to radiation of multicellular tumour spheroids assuming position- and volume-dependent radiosensitivity. We propose a method to calculate the overall radiosensitivity parameters to obtain the surviving fraction of tumours. A mathematical model of a spherical tumour with a hypoxic co...

journal_title：Physics in medicine and biology

authors： Horas JA,Olguin OR,Rizzotto MG

更新日期：2005-04-21 00:00:00

abstract：:Fast calculation or simulation of the ablation zone induced by radiofrequency ablation (RFA) has a critical role in hepatic RFA planning and therapy. However, it remains challenging to approximate the ablation zone in real time, especially when more than one probe is involved in one ablation session. This paper presen...

journal_title：Physics in medicine and biology

authors： Chen R,Zhang J,Kong D,Lou Q,Lu F

更新日期：2021-01-27 00:00:00

abstract：:Optical topography is a method for visualization of conical activity. Ways of improving the spatial resolution of the topographical image with three arrangements of optical fibres are discussed. A distribution of sensitivity is obtained from the phantom experiment, and used to reconstruct topographical images of an ac...

journal_title：Physics in medicine and biology

authors： Yamamoto T,Maki A,Kadoya T,Tanikawa Y,Yamad Y,Okada E,Koizumi H

更新日期：2002-09-21 00:00:00

abstract：:Contemporary imaging modalities can now provide the surgeon with high quality three- and four-dimensional images depicting not only normal anatomy and pathology, but also vascularity and function. A key component of image-guided surgery (IGS) is the ability to register multi-modal pre-operative images to each other an...

journal_title：Physics in medicine and biology

authors： Peters TM

更新日期：2006-07-21 00:00:00

abstract：:Temporal regularization plays a critical role in cardiac gated dynamic SPECT reconstruction, of which the goal is to obtain an image sequence from a single acquisition which simultaneously shows both cardiac motion and tracer distribution change over the course of imaging (termed 5D). In our recent work, we explored t...

journal_title：Physics in medicine and biology

authors： Niu X,Yang Y,King MA

更新日期：2012-09-07 00:00:00

abstract：:K-edge subtraction (KES) imaging is a technique able to map a specific element such as e.g. a contrast agent within the tissues, by exploiting the sharp rise of its absorption coefficient at the K-edge energy. Whereas mainly explored at synchrotron radiation sources, the energy discrimination properties of modern x-ra...

journal_title：Physics in medicine and biology

authors： Brun F,Di Trapani V,Albers J,Sacco P,Dreossi D,Brombal L,Rigon L,Longo R,Mittone A,Dullin C,Bravin A,Delogu P

更新日期：2020-03-06 00:00:00

abstract：:This paper describes the algorithm and examines the performance of an intensity-modulated radiation therapy (IMRT) beam-angle optimization (BAO) system. In this algorithm successive sets of beam angles are selected from a set of predefined directions using a fast simulated annealing (FSA) algorithm. An IMRT beam-profi...

journal_title：Physics in medicine and biology

authors： Djajaputra D,Wu Q,Wu Y,Mohan R

更新日期：2003-10-07 00:00:00

abstract：:An overview of the theory of 4D image reconstruction for emission tomography is given along with a review of the current state of the art, covering both positron emission tomography and single photon emission computed tomography (SPECT). By viewing 4D image reconstruction as a matter of either linear or non-linear par...

journal_title：Physics in medicine and biology

authors： Reader AJ,Verhaeghe J

更新日期：2014-11-21 00:00:00

abstract：:The purpose of this work was to study and quantify the differences in dose distributions computed with some of the newest dose calculation algorithms available in commercial planning systems. The study was done for clinical cases originally calculated with pencil beam convolution (PBC) where large density inhomogeneit...

journal_title：Physics in medicine and biology

authors： Hasenbalg F,Neuenschwander H,Mini R,Born EJ

更新日期：2007-07-07 00:00:00

abstract：:Digital phantoms continue to play a significant role in modeling and characterizing medical imaging. The currently available XCAT phantom incorporates both the flexibility of mathematical phantoms and the realistic nature of voxelized phantoms. This phantom generates images based on a regular breathing pattern and can...

journal_title：Physics in medicine and biology

authors： Mishra P,St James S,Segars WP,Berbeco RI,Lewis JH

更新日期：2012-06-07 00:00:00

abstract：:EGSnrc Monte Carlo simulation was used to investigate dose perturbation effects in prostate seed implant brachytherapy using 125I radioactive seeds used in implant brachytherapy. Dose perturbation effects resulting from the seed mutual attenuation in a prostate seed implant consisting of 27 seeds were investigated. Th...

journal_title：Physics in medicine and biology

authors： Mobit P,Badragan I

更新日期：2004-07-21 00:00:00

abstract：:We discuss the use of terahertz time domain spectroscopy for studies of conformational flexibility and conformational change in biomolecules. Protein structural dynamics are vital to biological function with protein flexibility affecting enzymatic reaction rates and sensory transduction cycling times. Conformational m...

journal_title：Physics in medicine and biology

authors： Markelz A,Whitmire S,Hillebrecht J,Birge R

更新日期：2002-11-07 00:00:00

abstract：:Electronic article surveillance (EAS) devices are widely used in most stores as anti-theft systems. In this work, the compliance with international guidelines in the human exposure to these devices is analysed by using the finite-difference time-domain (FDTD) method. Two sets of high resolution numerical phantoms of d...

journal_title：Physics in medicine and biology

authors： Martínez-Búrdalo M,Sanchis A,Martín A,Villar R

更新日期：2010-02-21 00:00:00

abstract：:The total system error (TSE) of a CyberKnife® system was measured using two phantom-based methods and one patient-based method. The standard radiochromic film (RCF) end-to-end (E2E) test using an anthropomorphic head and neck phantom and isocentric treatment delivery was used with the 6Dskull, Fiducial and Xsight® spi...

journal_title：Physics in medicine and biology

authors： Pantelis E,Moutsatsos A,Antypas C,Zoros E,Pantelakos P,Lekas L,Romanelli P,Zourari K,Hourdakis CJ

更新日期：2018-08-20 00:00:00

abstract：:The x-ray exposure to patients has become a major concern in computed tomography (CT) and minimizing the radiation exposure has been one of the major efforts in the CT field. Due to plenty high-attenuation tissues in the human chest, under low-dose scan protocols, thoracic low-dose CT (LDCT) images tend to be severely...

journal_title：Physics in medicine and biology

authors： Chen Y,Yang Z,Hu Y,Yang G,Zhu Y,Li Y,Luo L,Chen W,Toumoulin C

更新日期：2012-05-07 00:00:00

abstract：:An accurate, low noise estimate of photon attenuation in the subject is required for quantitative microPET studies of molecular tracer distributions in vivo. In this work, several transmission-based measurement techniques were compared, including coincidence mode with and without rod windowing, singles mode with two d...

journal_title：Physics in medicine and biology

authors： Lehnert W,Meikle SR,Siegel S,Newport D,Banati RB,Rosenfeld AB

更新日期：2006-08-21 00:00:00

abstract：:The least known parameters in a Monte Carlo simulation of a linear accelerator treatment head are often the properties of the initial electron beam directed onto the exit vacuum window. Several initial beams with different spatial fluence distributions, angular divergences and energy spectra have been transported thro...

journal_title：Physics in medicine and biology

authors： Björk P,Knöös T,Nilsson P

更新日期：2002-11-21 00:00:00

abstract：:A computer method has been developed which uses the time domain finite-difference (TDFD) algorithm to calculate the deposition of the electromagnetic (EM) field in three-dimensional biological models. This, the first of two papers, describes the algorithm and the computer programs developed. The method is demonstrated...

journal_title：Physics in medicine and biology

authors： Lau RW,Sheppard RJ

更新日期：1986-11-01 00:00:00

abstract：:We developed an anatomy-guided 4D closed-form algorithm to directly reconstruct parametric images from projection data for (nearly) irreversible tracers. Conventional methods consist of individually reconstructing 2D/3D PET data, followed by graphical analysis on the sequence of reconstructed image frames. The propose...

journal_title：Physics in medicine and biology

authors： Tang J,Kuwabara H,Wong DF,Rahmim A

更新日期：2010-08-07 00:00:00

abstract：:This work is a follow-up study for a recently-proposed 3D radiochromic gel dosimeter that contains a tetrazolium salt and a physical gel matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127). Several tetrazolium salts were examined in this work, including tetrazoli...

journal_title：Physics in medicine and biology

authors： Kwiatos K,Maras P,Kadlubowski S,Stempień Z,Dudek M,Kozicki M

更新日期：2018-05-04 00:00:00

abstract：:Carotid atherosclerosis measurements for eight subjects at baseline and 14 +/- 2 days later were examined using 1.5 T and 3.0 T magnetic resonance imaging (MRI). A single observer blinded to field strength, subject and timepoint manually segmented carotid artery wall and lumen boundaries in randomized images in five m...

journal_title：Physics in medicine and biology

authors： Vidal A,Bureau Y,Wade T,Spence JD,Rutt BK,Fenster A,Parraga G

更新日期：2008-12-07 00:00:00

abstract：:A special parallel-plate ionization chamber was developed. The motivation for the construction of this new chamber was mainly to fulfil the need of a reference system for computed tomography standard beams in the Calibration Laboratory of IPEN. However, the chamber was tested also in standard radiation beams of mammog...

journal_title：Physics in medicine and biology

authors： Maia AF,Caldas LV

更新日期：2005-08-21 00:00:00

abstract：:Several papers have recently addressed the issue of estimating chromophore concentration in optoacoustic imaging (OAI) using multiple wavelengths. The choice of wavelengths obviously affects the accuracy and precision of the estimates. One might assume that the wavelengths that maximize the extinction coefficients of ...

journal_title：Physics in medicine and biology

authors： Modgil D,La Riviére PJ

更新日期：2010-12-07 00:00:00

abstract：:Measurements of patient entrance surface dose rate provide valuable data for interpreting results from dose-area product studies on fluoroscopic x-ray equipment. Methods for measurement of entrance surface dose rate with backscatter and incident dose rate without backscatter have been investigated. Entrance surface do...

journal_title：Physics in medicine and biology

authors： Martin CJ

更新日期：1995-05-01 00:00:00

abstract：:In CT imaging, a variety of applications exist which are strongly SNR limited. However, in some cases redundant data of the same body region provide additional quanta. Examples in dual energy CT, the spatial resolution has to be compromised to provide good SNR for material decomposition. However, the respective spectr...

journal_title：Physics in medicine and biology

authors： Bruder H,Raupach R,Sunnegardh J,Allmendinger T,Klotz E,Stierstorfer K,Flohr T

更新日期：2015-11-07 00:00:00

abstract：:W (the average energy to form an ion pair) for 5.4 MeV 241Am alpha particles in a Rossi-type tissue-equivalent (TE) gas, argon and methane was determined to an accuracy better than 0.2% using a new automated data handling system. A vibrating reed electrometer and current digitiser were used to measure the current prod...

journal_title：Physics in medicine and biology

authors： Krieger GL,Baum JW,Varma MN,Beach JL

更新日期：1979-03-01 00:00:00

abstract：:Determination of the cardiorespiratory phase of the heart has numerous applications during cardiac imaging. In this article we propose a novel view-angle independent near-real time cardiorespiratory motion gating and coronary sinus (CS) catheter tracking technique for x-ray fluoroscopy images that are used to guide ca...

journal_title：Physics in medicine and biology

authors： Panayiotou M,Rhode KS,King AP,Ma Y,Cooklin M,O'Neill M,Gill J,Rinaldi CA,Housden RJ

更新日期：2015-10-21 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

authors： Soole BW

更新日期：1977-03-01 00:00:00