A radiographic technique for measuring the powder packing density in the cavities of trabecular bone.

abstract：:We report on a radiographic measurement of an ex vivo human knee using a grating-based phase-contrast imaging setup and a medical x-ray tube at a tube voltage of 70 kV. The measurement has been carried out using a Talbot-Lau setup that is suitable to achieve a high visibility in the energy regime of medical imaging. I...

journal_title：Physics in medicine and biology

authors： Horn F,Gelse K,Jabari S,Hauke C,Kaeppler S,Ludwig V,Meyer P,Michel T,Mohr J,Pelzer G,Rieger J,Riess C,Seifert M,Anton G

更新日期：2017-08-01 00:00:00

abstract：:This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical obs...

journal_title：Physics in medicine and biology

authors： Lee TS,Frey EC,Tsui BM

更新日期：2015-04-07 00:00:00

abstract：:Computer tomographic (CT) scans are used to correct for tissue inhomogeneities in radiotherapy treatment planning. In order to guarantee a precise treatment, it is important to obtain the relationship between CT Hounsfield units and electron densities (or proton stopping powers for proton radiotherapy), which is the b...

journal_title：Physics in medicine and biology

authors： Schneider U,Pedroni E,Lomax A

更新日期：1996-01-01 00:00:00

abstract：:A technique is presented to allow a breathing pattern to be obtained from any multi-slice CT, cone-beam or other series of sequential chest x-ray image sets. The technique requires no extra signals to be recorded and does not need specific external or internal oscillating structures to be visible in the field of view....

journal_title：Physics in medicine and biology

authors： Kavanagh A,Evans PM,Hansen VN,Webb S

更新日期：2009-08-21 00:00:00

abstract：:The dynamic magnetization of immobilized spherical single-domain magnetic nanoparticles (MNPs) with uniaxial or cubic magnetocrystalline anisotropy was studied computationally by executing simulations based on the Landau-Lifshitz-Gilbert (LLG) equation. For situations when a static magnetic field was suddenly applied ...

journal_title：Physics in medicine and biology

authors： Zhao Z,Garraud N,Arnold DP,Rinaldi C

更新日期：2020-01-17 00:00:00

abstract：:In this study, the quantitative accuracy of different attenuation correction strategies presently available for the High Resolution Research Tomograph (HRRT) was investigated. These attenuation correction methods differ in reconstruction and processing (segmentation) algorithms used for generating a micro-image from m...

journal_title：Physics in medicine and biology

authors： van Velden FH,Kloet RW,van Berckel BN,Molthoff CF,de Jong HW,Lammertsma AA,Boellaard R

更新日期：2008-01-07 00:00:00

abstract：:This paper reports an inverse arc-modulated radiation therapy planning technique based on linear models. It is implemented with a two-step procedure. First, fluence maps for 36 fixed-gantry beams are generated using a linear model-based intensity-modulated radiation therapy (IMRT) optimization algorithm. The 2D fluenc...

journal_title：Physics in medicine and biology

authors： Zhu X,Thongphiew D,McMahon R,Li T,Chankong V,Yin FF,Wu QJ

更新日期：2010-07-07 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：:For the first time the absolute photon mass energy-absorption coefficient of air in the energy range of 10 to 60 keV has been measured with relative standard uncertainties below 1%, considerably smaller than those of up to 2% assumed for calculated data. For monochromatized synchrotron radiation from the electron stor...

journal_title：Physics in medicine and biology

authors： Buhr H,Büermann L,Gerlach M,Krumrey M,Rabus H

更新日期：2012-12-21 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：:In order to measure in vivo resistivity of tissues in the thorax, the possibility of combining anatomical data extracted from high-resolution images with multiple-electrode impedance measurements, a priori knowledge of the range of tissue resistivities, and a priori data on the instrumentation noise is assessed in thi...

journal_title：Physics in medicine and biology

authors： Eyüboğlu BM,Pilkington TC,Wolf PD

更新日期：1994-01-01 00:00:00

abstract：:Contrast enhanced ultrasound (CEUS) and dynamic contrast enhanced ultrasound (DCE-US) can be used to provide information about the vasculature aiding diagnosis and monitoring of a number of pathologies including cancer. In the development of a CEUS imaging system, there are many choices to be made, such as whether to ...

journal_title：Physics in medicine and biology

authors： Moghimirad E,Bamber J,Harris E

更新日期：2019-04-23 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：: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

abstract：:In this paper, a coupled radiative transfer equation and diffusion approximation model is extended for light propagation in turbid medium with low-scattering and non-scattering regions. The light propagation is modelled with the radiative transfer equation in sub-domains in which the assumptions of the diffusion appro...

journal_title：Physics in medicine and biology

authors： Tarvainen T,Vauhkonen M,Kolehmainen V,Arridge SR,Kaipio JP

更新日期：2005-10-21 00:00:00

abstract：:In order to analyse the respective roles of ion concentration and fractional volume of the interstitial compartment as determinants of the impedance, Z, of renal medullary tissue, a model was needed in which both these factors could be varied independently. An array of blood cell suspensions ions in saline (different ...

journal_title：Physics in medicine and biology

authors： Niewiadomski W,Sadowski J,Badzyńska B,Rasmussen SN

更新日期：1990-11-01 00:00:00

abstract：:A method is presented for extraction of intra and inter fraction motion of seeds/markers within the patient from cone beam CT (CBCT) projection images. The position of the marker is determined on each projection image and fitted to a function describing the projection of a fixed point onto the imaging panel at differe...

journal_title：Physics in medicine and biology

authors： Marchant TE,Amer AM,Moore CJ

更新日期：2008-02-21 00:00:00

abstract：:A two-probe technique has been developed to measure 125I in the thyroid. In this technique simultaneous emissions from a source are detected as coincidence events between two probes rather than as a sum peak in a single probe (the sum peak method). The background count rate when counting coincidence events between pro...

journal_title：Physics in medicine and biology

authors： Burns PA,Peggie JR

更新日期：1980-05-01 00:00:00

abstract：:In this paper, we investigate an off-line strategy to incorporate inter-fraction organ motion in IMRT treatment planning. It was suggested that inverse planning could be based on a probability distribution of patient geometries instead of a single snap shot. However, this concept is connected to two intrinsic problems...

journal_title：Physics in medicine and biology

authors： Unkelbach J,Oelfke U

更新日期：2004-09-07 00:00:00

abstract：:A method of radiation dosimetry is described which is based on the radiation-induced initiation of polymerization of a bulk monomer (e.g. methyl methacrylate) containing a small concentration (about 100 ppm) of a compound which is non-fluorescent but which becomes highly fluorescent when it is incorporated into a grow...

journal_title：Physics in medicine and biology

authors： Warman JM,de Haas MP,Luthjens LH

更新日期：2009-05-21 00:00:00

abstract：:The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling;...

journal_title：Physics in medicine and biology

authors： Simon JC,Sapozhnikov OA,Kreider W,Breshock M,Williams JC,Bailey MR

更新日期：2018-01-09 00:00:00

abstract：:Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measure...

journal_title：Physics in medicine and biology

authors： Viator JA,Choi B,Peavy GM,Kimel S,Nelson JS

更新日期：2003-01-21 00:00:00

abstract：:Discrete implanted liver tumours in the rat have been exposed to arrays of 1.7 MHz ultrasound lesions. Focal peak intensities in the range 1.4-3.5 k Wcm-2 were used for an exposure time of 10 s. It has been demonstrated that where the whole tumour volume was exposed to the focused ultrasound beam, no evidence of tumou...

journal_title：Physics in medicine and biology

authors： ter Haar G,Rivens I,Chen L,Riddler S

更新日期：1991-11-01 00:00:00

abstract：:A method to determine the spectrum of a clinical photon beam from measured depth-dose data is described. At shallow depths, where the range of Compton-generated electrons increases rapidly with photon energy, the depth dose provides the information to discriminate the spectral contributions. To minimize the influence ...

journal_title：Physics in medicine and biology

authors： Bloch P,Altschuler MD,Bjärngard BE,Kassaee A,McDonough J

更新日期：2000-01-01 00:00:00

abstract：:Iterative image reconstruction algorithms have the potential to produce low noise images. Early stopping of the iteration process is problematic because some features of the image may converge slowly. On the other hand, there may be noise build-up with increased number of iterations. Therefore, we examined the stabili...

journal_title：Physics in medicine and biology

authors： Chlewicki W,Hermansen F,Hansen SB

更新日期：2004-10-21 00:00:00

abstract：:Scattered radiation from within the treatment head can contribute significant dose to all parts of a radiotherapy treatment field. A multileaf collimator may be used to create an arbitrarily shaped field, and may also be used, under dynamic control, to modulate the beam intensity over the field. This method of intensi...

journal_title：Physics in medicine and biology

authors： Hounsell AR,Wilkinson JM

更新日期：1997-09-01 00:00:00

abstract：:Picking geometrically relevant atlases from the whole training set is crucial to multi-atlas based image segmentation, especially with extensive data of heterogeneous quality in the Big Data era. Unfortunately, there is very limited understanding of how currently used image similarity criteria reveal geometric relevan...

journal_title：Physics in medicine and biology

authors： Zhao T,Ruan D

更新日期：2016-06-07 00:00:00

abstract：:Remission spectroscopy in living tissues can only be performed because scattering processes induce a pronounced amount of backscattered light. New types of scattering chambers were constructed in order to investigate the angular distribution of light intensities caused by scattering events typical for living tissues. ...

journal_title：Physics in medicine and biology

authors： Frank KH,Kessler M,Appelbaum K,Albrecht HP,Mauch ED

更新日期：1989-12-01 00:00:00

abstract：:Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry ...

journal_title：Physics in medicine and biology

authors： Afsharpour H,Landry G,D'Amours M,Enger S,Reniers B,Poon E,Carrier JF,Verhaegen F,Beaulieu L

更新日期：2012-06-07 00:00:00

abstract：:Quantitative Yttrium-90 ((90)Y) bremsstrahlung single photon emission computed tomography (SPECT) imaging has shown great potential to provide reliable estimates of (90)Y activity distribution for targeted radionuclide therapy dosimetry applications. One factor that potentially affects the reliability of the activity ...

journal_title：Physics in medicine and biology

authors： Rong X,Du Y,Frey EC

更新日期：2012-06-21 00:00:00