On MEG forward modelling using multipolar expansions.

abstract：:The use of calibrated tissue-equivalent (TE) ionisation chambers is commonly considered to be the most practical method for total absorbed dose determinations in mixed neutron-photon fields for biomedical applications. The total absorbed dose can be derived from the charge produced within the cavity of an ionisation c...

journal_title：Physics in medicine and biology

authors： Zoetelief J,Broerse JJ

更新日期：1983-05-01 00:00:00

abstract：:The classical Sievert integral method is a valuable tool for dose rate calculations around brachytherapy sources, combining simplicity with reasonable computational times. However, its accuracy in predicting dose rate anisotropy around 192Ir brachytherapy sources has been repeatedly put into question. In this work, we...

journal_title：Physics in medicine and biology

authors： Karaiskos P,Angelopoulos A,Baras P,Rozaki-Mavrouli H,Sandilos P,Vlachos L,Sakelliou L

更新日期：2000-02-01 00:00:00

abstract：:Using a statistical (chi-square) test on simulated data and a realistic noise model derived from the system's hardware we study the performance of diffuse optical tomography systems for fluorescence imaging. We compare the predicted smallest size of detectable lesions at various positions in slab and cup geometry and ...

journal_title：Physics in medicine and biology

authors： Ziegler R,Brendel B,Rinneberg H,Nielsen T

更新日期：2009-01-21 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：:Four-dimensional computed tomography (4D-CT) requires breathing information from the patient, and for this, several systems are available. Testing of these systems, under realistic conditions, requires a phantom with a moving target and an expandable outer contour. An anthropomorphic phantom was developed to simulate ...

journal_title：Physics in medicine and biology

authors： Vásquez AC,Runz A,Echner G,Sroka-Perez G,Karger CP

更新日期：2012-05-07 00:00:00

abstract：:We evaluated the basic properties of a commercially available BANGkit gel dosimeter, which is a normoxic type of BANG gel. This gel-kit has the same composition as the BANG 3 gel, but is fully oxygenated. To exclude oxygen, oxygen scavenging ascorbic acid and copper sulfate as a catalyst are used. The properties that ...

journal_title：Physics in medicine and biology

authors： Murakami Y,Nakashima T,Watanabe Y,Akimitsu T,Matsuura K,Kenjo M,Kaneyasu Y,Wadasaki K,Hirokawa Y,Ito K

更新日期：2007-04-21 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：:Multi-atlas segmentation (MAS) has been widely used to automate the delineation of organs at risk (OARs) for radiotherapy. Label fusion is a crucial step in MAS to cope with the segmentation variabilities among multiple atlases. However, most existing label fusion methods do not consider the potential dosimetric impac...

journal_title：Physics in medicine and biology

authors： Chang J,Tian Z,Lu W,Gu X,Chen M,Jiang SB

更新日期：2017-05-07 00:00:00

abstract：:This paper reports a theoretical study on the distribution of blood flow in the human cardiovascular system when one or more blood vessels are affected by stenosis. The analysis employs a mathematical model of the entire system based on the finite element method. The arterial-venous network is represented by a large n...

journal_title：Physics in medicine and biology

authors： Sud VK,Srinivasan RS,Charles JB,Bungo MW

更新日期：1993-03-01 00:00:00

abstract：:We implemented a hybrid scatter-correction method for 3D PET that combines two scatter-correction methods in a complementary way. The implemented scheme uses a method based on the discrimination of the energy of events (the estimation of trues method (ETM)) and an auxiliary method (the single scatter simulation method...

journal_title：Physics in medicine and biology

authors： Ferreira NC,Trébossen R,Lartizien C,Brulon V,Merceron P,Bendriem B

更新日期：2002-05-07 00:00:00

abstract：:A micro-multileaf collimator (microMLC) for stereotactic radiosurgery is used for determination of the spatial intensity distribution of the photon source of a linear accelerator. The method is based on grid field dose measurements using film dosimetry and is easy to perform. Since the microMLC does not allow 'direct'...

journal_title：Physics in medicine and biology

authors： Treuer H,Hoevels M,Luyken K,Hunsche S,Kocher M,Müller RP,Sturm V

更新日期：2003-08-07 00:00:00

abstract：:A motorized electron multileaf collimator (eMLC) was developed as an add-on device to the Varian linac for delivery of advanced electron beam therapy. It has previously been shown that electron beams collimated by an eMLC have very similar penumbra to those collimated by applicators and cutouts. Thus, manufacturing pa...

journal_title：Physics in medicine and biology

authors： Eldib A,Jin L,Li J,Ma CM

更新日期：2013-08-21 00:00:00

abstract：:All available imaging devices in nuclear medicine have finite energy resolution. This leads to inclusion of scattered radiation, which in turn degrades the image quality. Different scatter correction schemes therefore try to eliminate the effect of scattered radiation. On the other hand, improvement of the camera's in...

journal_title：Physics in medicine and biology

authors： Wirth V

更新日期：1989-01-01 00:00:00

abstract：:By the end of 2002, 33 398 patients worldwide had been treated with proton radiotherapy, 10 829 for eye diseases. The dose prediction algorithms used today for ocular proton therapy treatment planning rely on parameterizations of measured proton dose distributions, i.e., broad-beam and pencil-beam techniques, whose pr...

journal_title：Physics in medicine and biology

authors： Newhauser W,Koch N,Hummel S,Ziegler M,Titt U

更新日期：2005-11-21 00:00:00

abstract：:In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 microm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity....

journal_title：Physics in medicine and biology

authors： Osterås BH,Hole EO,Olsen DR,Malinen E

更新日期：2006-12-21 00:00:00

abstract：:A general theory is presented for minimizing noise in linear dimension reduction of sequences of medical images when the factors and the covariance matrix and mean of the noise are given. A dimension reduction is optimal when all diagonal elements in the covariance matrix of the noise in the signal (factor) space are ...

journal_title：Physics in medicine and biology

authors： Hermansen F,Lammertsma AA

更新日期：1995-11-01 00:00:00

abstract：:Radiation dose distributions have been calculated for 188Re and 32P activity on a coronary artery stent. The doses have been calculated both as a function of position along the stent and of depth into the artery wall. Comparisons of the dose from identical activities of 188Re and 32P on the stent show that the major d...

journal_title：Physics in medicine and biology

authors： Fox RA,Henson PW

更新日期：2000-12-01 00:00:00

abstract：:With high-dose administration of (90)Y labeled antibodies, it is possible to image (90)Y without an admixture of (111)In. We have earlier shown that it is possible to perform quantitative (90)Y bremsstrahlung SPECT for dosimetry purposes with reasonable accuracy. However, whole-body (WB) activity quantification with t...

journal_title：Physics in medicine and biology

authors： Minarik D,Ljungberg M,Segars P,Gleisner KS

更新日期：2009-10-07 00:00:00

abstract：:The purpose of this study is to investigate whether quality assurance (QA) for cone-beam computed tomography (CBCT) image rotation is necessary in order to ensure the accuracy of CBCT based image-guided radiation therapy (IGRT) and adaptive radiotherapy (ART). Misregistration of angular coordinates during CBCT acquisi...

journal_title：Physics in medicine and biology

authors： Ayan AS,Lin H,Yeager C,Deville C,McDonough J,Zhu TC,Anderson N,Bar Ad V,Lu HM,Both S

更新日期：2013-02-21 00:00:00

abstract：:This paper investigates cone-beam tomography for a wide class of x-ray source trajectories called saddles. In particular, a mathematical analysis of the number of intersections between a saddle and an arbitrary plane is given. This analysis demonstrates that axially truncated cone-beam projections acquired along a sad...

journal_title：Physics in medicine and biology

authors： Pack JD,Noo F,Kudo H

更新日期：2004-06-07 00:00:00

abstract：:This work discusses the substitution of a gelatine physical gel matrix with a matrix made of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) in five 3D radiotherapy polymer gel dosimeters: MAGAT, PAGAT, NIPAM, VIPARnd (VIP) and VIPARCT (VIC). The current research outcomes s...

journal_title：Physics in medicine and biology

authors： Jaszczak M,Wach R,Maras P,Dudek M,Kozicki M

更新日期：2018-09-06 00:00:00

abstract：:Oxygen ([Formula: see text]) ions are a potential alternative to carbon ions in ion beam therapy. Their enhanced linear energy transfer indicates a higher relative biological effectiveness and a reduced oxygen enhancement ratio. Due to the limited availability of [Formula: see text] ion beams, Monte Carlo (MC) transpo...

journal_title：Physics in medicine and biology

authors： Resch AF,Fuchs H,Georg D

更新日期：2017-09-05 00:00:00

abstract：:Image reconstruction of ultrasound computed tomography based on the wave equation is able to show much more structural details than simpler ray-based image reconstruction methods. However, to invert the wave-based forward model is computationally demanding. To address this problem, we develop an efficient fully learne...

journal_title：Physics in medicine and biology

authors： Zhao W,Wang H,Gemmeke H,van Dongen KWA,Hopp T,Hesser J

更新日期：2020-11-27 00:00:00

abstract：:An algorithm for dynamic multileaf-collimator (dMLC) tracking of a target performing a known a priori, rigid-body motion during volumetric modulated arc therapy (VMAT), has been experimentally validated and applied to investigate the potential of the Agility (Elekta AB, Stockholm, Sweden) multileaf-collimator (MLC) fo...

journal_title：Physics in medicine and biology

authors： Davies GA,Clowes P,Bedford JL,Evans PM,Webb S,Poludniowski G

更新日期：2013-07-07 00:00:00

abstract：:The dosimetrical characteristics of a new miniature multileaf collimator (ModuLeaf MLC, MRC Systems GmbH, Heidelberg, Germany) attached to the accessory holder of a Siemens accelerator with 6 MV x-rays (PRIMUS, Siemens OCS, Concord, California, USA) have been investigated. In particular, those parameters which are imp...

journal_title：Physics in medicine and biology

authors： Hartmann GH,Föhlisch F

更新日期：2002-06-21 00:00:00

abstract：:Cavity theories are used to relate the dose in a medium to the dose in a cavity. No satisfactory analytical approach exists for the case of intermediate cavities, such as TLDs, when interface effects are important. Burlin proposed a general cavity theory that accounts for the cavity size but which ignores interface ef...

journal_title：Physics in medicine and biology

authors： Frujinoiu C

更新日期：2001-04-01 00:00:00

abstract：:Diffusion tensor tractography (DTT) allows one to explore axonal connectivity patterns in neuronal tissue by linking local predominant diffusion directions determined by diffusion tensor imaging (DTI). The majority of existing tractography approaches use continuous coordinates for calculating single trajectories throu...

journal_title：Physics in medicine and biology

authors： Bodammer NC,Kaufmann J,Kanowski M,Tempelmann C

更新日期：2009-02-21 00:00:00

abstract：:The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discu...

journal_title：Physics in medicine and biology

authors： Barrett HH,Myers KJ,Hoeschen C,Kupinski MA,Little MP

更新日期：2015-01-21 00:00:00

abstract：:We have developed an x-ray imaging system for in vivo four-dimensional computed tomography (4DCT) of small animals for pre-clinical lung investigations. Our customized laboratory facility is capable of high resolution in vivo imaging at high frame rates. Characterization using phantoms demonstrate a spatial resolution...

journal_title：Physics in medicine and biology

authors： Preissner M,Murrie RP,Pinar I,Werdiger F,Carnibella RP,Zosky GR,Fouras A,Dubsky S

更新日期：2018-04-20 00:00:00

abstract：:We propose a hybrid multiobjective (MO) evolutionary optimization algorithm (MOEA) for intensity-modulated radiotherapy inverse planning and apply it to optimize the number of incident beams, their orientations and intensity profiles. The algorithm produces a set of efficient solutions, which represent different clini...

journal_title：Physics in medicine and biology

authors： Schreibmann E,Lahanas M,Xing L,Baltas D

更新日期：2004-03-07 00:00:00