Estimation of tissue resistivities from multiple-electrode impedance measurements.

abstract：:The combined build-up and attenuation factor, B exp (-mu r), of point isotropic photon sources in a water medium has been calculated using the Monte Carlo method, for energies (20-1500 keV) and distances (1-10 cm) relevant in brachytherapy. For the transport of photons and electrons, up-to-date and self-consistent tot...

journal_title：Physics in medicine and biology

authors： Angelopoulos A,Perris A,Sakellariou K,Sakelliou L,Sarigiannis K,Zarris G

更新日期：1991-06-01 00:00:00

abstract：:A method of computing theoretical X-ray spectra in the range 30-150 kV is presented. The theoretical spectra are compared with constant potential, high resolution spectra from a tungsten target measured with a Ge(Li) detector, for a range of target angles, tube voltage and filtrations. Above 100 kV the spectra were al...

journal_title：Physics in medicine and biology

authors： Birch R,Marshall M

更新日期：1979-05-01 00:00:00

abstract：:Detectors used for positron emission tomography (PET) provide fast, randomly distributed signals that need to be digitized for further processing. One possibility is to sample the signals at the peak initiated by a trigger from a constant fraction discriminator (CFD). For PET detectors, simultaneous acquisition of man...

journal_title：Physics in medicine and biology

authors： Judenhofer MS,Pichler BJ,Cherry SR

更新日期：2005-01-07 00:00:00

abstract：:A phantom study for dosimetry in the urethra using alanine/ESR during (192)Ir HDR brachytherapy of prostate cancer is presented. The measurement method of the secondary standard of the Physikalisch-Technische Bundesanstalt had to be slightly modified in order to be able to measure inside a Foley catheter. The absorbed...

journal_title：Physics in medicine and biology

authors： Anton M,Wagner D,Selbach HJ,Hackel T,Hermann RM,Hess CF,Vorwerk H

更新日期：2009-05-07 00:00:00

abstract：:We present a new method for automated characterization of atherosclerotic plaque composition in ex vivo MRI. It uses MRI intensities as well as four other types of features: smoothed, gradient magnitude and Laplacian images at several scales, and the distances to the lumen and outer vessel wall. The ground truth for f...

journal_title：Physics in medicine and biology

authors： van Engelen A,Niessen WJ,Klein S,Groen HC,Verhagen HJ,Wentzel JJ,van der Lugt A,de Bruijne M

更新日期：2012-01-07 00:00:00

abstract：:The purpose of this work was to use Monte Carlo simulations to verify the accuracy of the dose distributions from a commercial treatment planning optimization system (Corvus, Nomos Corp., Sewickley, PA) for intensity-modulated radiotherapy (IMRT). A Monte Carlo treatment planning system has been implemented clinically...

journal_title：Physics in medicine and biology

authors： Ma CM,Pawlicki T,Jiang SB,Li JS,Deng J,Mok E,Kapur A,Xing L,Ma L,Boyer AL

更新日期：2000-09-01 00:00:00

abstract：:Monte Carlo simulation techniques are applied to track the annihilation photons from positron decay, and store the photon histories. Reasonably realistic models of the isotope distribution in the brain and heart during typical PET studies, as well as the traditional phantoms used for measuring PET scanner performance ...

journal_title：Physics in medicine and biology

authors： Thompson CJ,Moreno-Cantu J,Picard Y

更新日期：1992-03-01 00:00:00

abstract：:Compromises in the design of a positron emission tomography (PET) insert for a magnetic resonance imaging (MRI) system should minimize the deterioration of image quality in both modalities, particularly when simultaneous demanding acquisitions are performed. In this work, the advantages of using individually read-out ...

journal_title：Physics in medicine and biology

authors： Omidvari N,Topping G,Cabello J,Paul S,Schwaiger M,Ziegler SI

更新日期：2018-05-01 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：:Single monochromator charge-coupled device (CCD) array spectroradiometers have the advantage of ease of use and speed compared with double grating instruments. Their inherently inferior stray-light rejection, however, can critically affect their accuracy in phototherapy and research-related dosimetry applications. Thi...

journal_title：Physics in medicine and biology

authors： Coleman A,Sarkany R,Walker S

更新日期：2008-09-21 00:00:00

abstract：:In this paper the propagation of a UWB pulse into a layered model of the human body is studied to characterize absorption and reflection of the UWB signal due to the different body tissues. Several time behaviours for the incident UWB pulse are considered and compared with reference to the feasibility of breath and he...

journal_title：Physics in medicine and biology

authors： Cavagnaro M,Pittella E,Pisa S

更新日期：2013-12-21 00:00:00

abstract：:An ultrahigh-resolution full-field optical coherence tomography (OCT) system has been developed for cellular-level imaging of biological media. The system is based on a Linnik interference microscope illuminated with a tungsten halogen lamp, associated with a high-resolution CCD camera. En face tomographic images are ...

journal_title：Physics in medicine and biology

authors： Dubois A,Moneron G,Grieve K,Boccara AC

更新日期：2004-04-07 00:00:00

abstract：:Four-dimensional volumetric modulated arc therapy (4D VMAT) is a treatment strategy for lung cancers that aims to exploit relative target and tissue motion to improve organ at risk (OAR) sparing. The algorithm incorporates the entire patient respiratory cycle using 4D CT data into the optimization process. Resulting t...

journal_title：Physics in medicine and biology

authors： Chin E,Loewen SK,Nichol A,Otto K

更新日期：2013-02-21 00:00:00

abstract：:We have developed an impedance magnetocardiogram (IMCG) system to detect the change of magnetic field corresponding to changes in blood volume in the heart. A low magnetic field from the electrical activity of the human heart--the so-called magnetocardiogram (MCG)--can be simultaneously detected by using this system. ...

journal_title：Physics in medicine and biology

authors： Kandori A,Miyashita T,Suzuki D,Yokosawa K,Tsukada K

更新日期：2001-02-01 00:00:00

abstract：:The S-value is a standard measure in cellular dosimetry. S-values are calculated by applying analytical methods or by Monte Carlo simulation. In Monte Carlo simulation, particles are either tracked individually event-by-event or close events are condensed and processed collectively in different steps. Both of these me...

journal_title：Physics in medicine and biology

authors： Tajik-Mansoury MA,Rajabi H,Mozdarani H

更新日期：2017-03-07 00:00:00

abstract：:The 'monoenergetic' electron loss model was derived in a previous work to account for pathlength straggling in the Fermi-Eyges pencil beam problem. In this paper, we extend this model to account for energy-loss straggling and secondary knock-on electron transport in order to adequately predict a depth dose curve. To m...

journal_title：Physics in medicine and biology

authors： Chvetsov AV,Sandison GA,Yeboah C

更新日期：2000-10-01 00:00:00

abstract：:Inverse treatment planning in intensity modulated particle therapy (IMPT) with scanned carbon-ion beams is currently based on the optimization of RBE-weighted dose to satisfy requirements of target coverage and limited toxicity to organs-at-risk (OARs) and healthy tissues. There are many feasible IMPT plans that meet ...

journal_title：Physics in medicine and biology

authors： Burigo LN,Ramos-Méndez J,Bangert M,Schulte RW,Faddegon B

更新日期：2019-01-04 00:00:00

abstract：:Transcranial direct current stimulation (tDCS) is a neuromodulation scheme where a small current is delivered to the brain via two electrodes attached to the scalp. The electrode design is an important topic, not only as regards efficacy, but also from a safety perspective, as tDCS may be related to skin lesions that ...

journal_title：Physics in medicine and biology

authors： Gomez-Tames J,Sugiyama Y,Laakso I,Tanaka S,Koyama S,Sadato N,Hirata A

更新日期：2016-12-21 00:00:00

abstract：:Segmented attenuation correction is now a widely accepted technique to reduce noise propagation from transmission scanning in positron emission tomography (PET). In this paper, we present a new method for segmenting transmission images in whole-body scanning. This reduces the noise in the correction maps while still c...

journal_title：Physics in medicine and biology

authors： Zaidi H,Diaz-Gomez M,Boudraa A,Slosman DO

更新日期：2002-04-07 00:00:00

abstract：:Absorbed dose values were determined under the reference conditions in a phantom irradiated by high-energy photon beams with quality varying between 60Co gamma rays and 25 MV X-rays, using four commonly employed types of ionisation chamber. The ionisation chamber readings were converted to absorbed dose values applyin...

journal_title：Physics in medicine and biology

authors： Mijnheer BJ,Wittkämper FW

更新日期：1986-04-01 00:00:00

abstract：:Experimental radiobiological investigations of fast neutron beams involve irradiation of thin cell layers. The irradiation of cells is done either in free air or with a material such as graphite, TE plastic or bone-equivalent plastic covering the cells. This paper discusses the computed dose distributions in LET at sh...

journal_title：Physics in medicine and biology

authors： Bhatia DP,Nagarajan PS

更新日期：1979-09-01 00:00:00

abstract：:A 3D anatomical computational model is developed to assess thermal effects due to exposure to the electromagnetic field required to power a new investigational active implantable microvalve for the treatment of glaucoma. Such a device, located in the temporal superior eye quadrant, produces a filtering bleb, which is ...

journal_title：Physics in medicine and biology

authors： Schaumburg F,Guarnieri FA

更新日期：2017-05-07 00:00:00

abstract：:Measurement of total body nitrogen is assuming increasing importance in the nutritional evaluation of seriously ill patients. Nitrogen has been previously measured either by counting (i) the annihilation radiation from 13N immediately after neutron irradiation with 14 MeV neutrons or (ii) the 'prompt' gamma rays from ...

journal_title：Physics in medicine and biology

authors： Spinks TJ,Goode AW,Ranicar AS,Steere E

更新日期：1984-04-01 00:00:00

abstract：:Transverse image truncation can be a serious problem for human imaging using cone-beam transmission CT (CB-CT) implemented on a conventional rotating gamma camera. If this problem can be solved, CB-CT will be useful for attenuation compensation of SPECT images. This paper presents a reconstruction method to reduce or ...

journal_title：Physics in medicine and biology

authors： Manglos SH

更新日期：1992-03-01 00:00:00

abstract：:In this paper, we present a segmentation and classification method for thyroid follicular neoplasms based on a combination of the prior-based level set method and deep convolutional neural network. The proposed method aims to discriminate thyroid follicular adenoma (TFA) and follicular thyroid carcinoma (FTC) in ultra...

journal_title：Physics in medicine and biology

authors： Yang B,Yan M,Yan Z,Zhu C,Xu D,Dong F

更新日期：2020-11-02 00:00:00

abstract：:A method will be described for determining the centre of rotation of a mechanically scanned reflection ultrasound computed tomography system. It is based on the principle of obtaining opposing images of a test object containing many point targets. The method is automatic in the sense that the centre of rotation is cal...

journal_title：Physics in medicine and biology

authors： Jago JR

更新日期：1994-12-01 00:00:00

abstract：:Computer aided detection (CADe) for breast lesion can provide an important reference for radiologists in breast cancer screening. Architectural distortion (AD) is a type of breast lesion that is difficult to detect. A majority of CADe methods focus on detecting the radial pattern, which is a main characteristic of typ...

journal_title：Physics in medicine and biology

authors： Li Y,He Z,Lu Y,Ma X,Guo Y,Xie Z,Xu Z,Chen W,Chen H

更新日期：2020-06-02 00:00:00

abstract：:Biomechanical model based deformable image registration has been widely used to account for prostate deformation in various medical imaging procedures. Biomechanical material properties are important components of a biomechanical model. In this study, the effect of incorporating tumor-specific material properties in t...

journal_title：Physics in medicine and biology

authors： Samavati N,McGrath DM,Jewett MA,van der Kwast T,Ménard C,Brock KK

更新日期：2015-01-07 00:00:00

abstract：:This study aims to build a feasible mathematical model to analyze the mass evolution of NSCLC during standard fractionated radiotherapy. Seventy-three cases of NSCLC who were received radiotherapy with prescription dose of 2 Gy  ×  30 fx were selected retrospectively and divided into adenocarcinoma (ADC) group and squ...

journal_title：Physics in medicine and biology

authors： Chen J,Wang K,Jian J,Zhang W

更新日期：2019-11-26 00:00:00

abstract：:A number of heating sources are available for minimally invasive thermal therapy of tumours. The purpose of this work was to compare, theoretically, the heating characteristics of interstitial microwave, laser and ultrasound sources in three tissue sites: breast, brain and liver. Using a numerical method, the heating ...

journal_title：Physics in medicine and biology

authors： Skinner MG,Iizuka MN,Kolios MC,Sherar MD

更新日期：1998-12-01 00:00:00