Total variation norm for three-dimensional iterative reconstruction in limited view angle tomography.

abstract：:The basic principles of x-ray image formation in radiology have remained essentially unchanged since Röntgen first discovered x-rays over a hundred years ago. The conventional approach relies on x-ray attenuation as the sole source of contrast and draws exclusively on ray or geometrical optics to describe and interpre...

journal_title：Physics in medicine and biology

authors： Bech M,Bunk O,Donath T,Feidenhans'l R,David C,Pfeiffer F

更新日期：2010-09-21 00:00:00

abstract：:Micro-CT is widely used in preclinical studies, generating substantial interest in extending its capabilities in functional imaging applications such as blood perfusion and cardiac function. However, imaging cardiac structure and function in mice is challenging due to their small size and rapid heart rate. To overcome...

journal_title：Physics in medicine and biology

authors： Holbrook M,Clark DP,Badea CT

更新日期：2018-01-09 00:00:00

abstract：:An inflatable endorectal balloon (ERB) is often used during stereotactic body radiation therapy (SBRT) for treatment of prostate cancer in order to reduce both intrafraction motion of the target and risk of rectal toxicity. However, the ERB can exert significant force on the prostate, and this work assessed the impact...

journal_title：Physics in medicine and biology

authors： Jones BL,Gan G,Kavanagh B,Miften M

更新日期：2013-11-21 00:00:00

abstract：:In this paper we present a novel method of reducing the dosimetric effects of the finite leaf width of a multileaf collimator (MLC) in conformal and intensity modulated radiotherapy (IMRT). This is achieved by decomposing the required high-resolution fluence distribution into two orthogonal components, which are deliv...

journal_title：Physics in medicine and biology

authors： Evans PM,Partridge M

更新日期：2000-03-01 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：:Intracoronary thermography is a technique that measures lumen wall temperatures for vulnerable plaque detection. In this paper the influence of vulnerable plaque composition on lumen wall temperatures was studied numerically. Concerning the vulnerable plaque heat generation, the location of the heat source and its hea...

journal_title：Physics in medicine and biology

authors： ten Have AG,Gijsen FJ,Wentzel JJ,Slager CJ,Serruys PW,van der Steen AF

更新日期：2006-11-21 00:00:00

abstract：:Investigate 3D (spatial and temporal) convolutional neural networks (CNNs) for real-time on-the-fly magnetic resonance imaging (MRI) reconstruction. In particular, we investigated the applicability of training CNNs on a patient-by-patient basis for the purpose of lung tumor segmentation. Data were acquired with our 3 ...

journal_title：Physics in medicine and biology

authors： Dietz B,Yun J,Yip E,Gabos Z,Fallone BG,Wachowicz K

更新日期：2019-09-23 00:00:00

abstract：:A mammogram is the standard modality used for breast cancer screening. Computer-aided detection (CAD) approaches are helpful for improving breast cancer detection rates when applied to mammograms. However, automated analysis of a mammogram often leads to inaccurate results in the presence of the pectoral muscle. There...

journal_title：Physics in medicine and biology

authors： Feudjio CK,Klein J,Tiedeu A,Colot O

更新日期：2013-12-07 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：:A photon diffusion model has been developed to calculate the steady-state spatially resolved fluorescence from pencil beam excitation in layered tissue. The model allows the calculation of both the excitation reflectance and the fluorescence escape for an arbitrary continuous depth distribution of tissue optical prope...

journal_title：Physics in medicine and biology

authors： Hyde DE,Farrell TJ,Patterson MS,Wilson BC

更新日期：2001-02-01 00:00:00

abstract：:Monte Carlo simulation of beam modifiers such as physical wedges and compensating filters has been performed with a rectilinear voxel geometry module. A modified version of the EGS4/DOSXYZ code has been developed for this purpose. The new implementations have been validated against the BEAM Monte Carlo code using its ...

journal_title：Physics in medicine and biology

authors： Spezi E,Lewis DG,Smith CW

更新日期：2001-11-01 00:00:00

abstract：:4D cone beam computed tomography (4DCBCT) is an emerging image guidance strategy used in radiotherapy where projections acquired during a scan are sorted into respiratory bins based on the respiratory phase or displacement. 4DCBCT reduces the motion blur caused by respiratory motion but increases streaking artefacts d...

journal_title：Physics in medicine and biology

authors： O'Brien RT,Kipritidis J,Shieh CC,Keall PJ

更新日期：2014-10-07 00:00:00

abstract：:The problem of fluorescence diffuse optical tomography consists in localizing fluorescent markers from near-infrared light measurements. Among the different available acquisition modalities, the time-resolved modality is expected to provide measurements of richer information content. To extract this information, the m...

journal_title：Physics in medicine and biology

authors： Ducros N,Hervé L,Da Silva A,Dinten JM,Peyrin F

更新日期：2009-12-07 00:00:00

abstract：:Radiotherapy treatment planning relies on the use of geometrically correct images. This paper presents a fully automatic tool for correcting MR images for the effects of B(0) inhomogeneities. The post-processing method is based on the gradient-reversal technique of Chang and Fitzpatrick (1992 IEEE Trans. Med. Imaging ...

journal_title：Physics in medicine and biology

authors： Reinsberg SA,Doran SJ,Charles-Edwards EM,Leach MO

更新日期：2005-06-07 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：:A three-dimensional spherical inclusion model that approximates a lesion bonded to a tissue matrix is proposed for biomedical elastography. Analytical formulae describing spatial strain and stress distributions generated in infinite media by uniform loading are given under a linear, homogeneous, isotropic elasticity a...

journal_title：Physics in medicine and biology

authors： Bilgen M,Insana MF

更新日期：1998-01-01 00:00:00

abstract：:Finite element (FE) modeling provides a useful tool to understand the mechanical behavior of complex tissues, such as cancers, in a variety of testing conditions. Although a number of numerical and analytical models for cancerous tumors are retrievable in the literature, none of these models is capable of completely d...

journal_title：Physics in medicine and biology

authors： Islam MT,Reddy JN,Righetti R

更新日期：2018-10-24 00:00:00

abstract：:Our goal was to develop a method for generating high-resolution three-dimensional pulmonary compliance images in rodents from computed tomography (CT) images acquired at a series of constant pressures in ventilated animals. One rat and one mouse were used to demonstrate this technique. A pre-clinical GE flat panel CT ...

journal_title：Physics in medicine and biology

authors： Guerrero T,Castillo R,Sanders K,Price R,Komaki R,Cody D

更新日期：2006-03-07 00:00:00

abstract：:Dose measurements following 10 min irradiations with a portable x-ray fluorescence spectrometer composed of a miniature x-ray tube and a silicon PiN diode detector were performed using thermoluminescent dosimeters consisting of LiF:Mg,Ti chips of 3 mm diameter and 0.4 mm thickness. The table-top setup of the spectrome...

journal_title：Physics in medicine and biology

authors： Gherase MR,Mader JE,Fleming DE

更新日期：2010-09-21 00:00:00

abstract：:The aim of this study is the evaluation of on-the-fly volume of intersection computation for system's geometry modelling in 3D PET image reconstruction. For this purpose we propose a simple geometrical model in which the cubic image voxels on the given Cartesian grid are approximated with spheres and the rectangular t...

journal_title：Physics in medicine and biology

authors： Lougovski A,Hofheinz F,Maus J,Schramm G,Will E,van den Hoff J

更新日期：2014-02-07 00:00:00

abstract：:The goal of this study is to demonstrate the feasibility of a novel non-coplanar-arc optimization algorithm (CyberArc). This method aims to reduce the delivery time of conventional CyberKnife treatments by allowing for continuous beam delivery. CyberArc uses a 4 step optimization strategy, in which nodes, beams, and c...

journal_title：Physics in medicine and biology

authors： Kearney V,Cheung JP,McGuinness C,Solberg TD

更新日期：2017-06-26 00:00:00

abstract：:It is well known that the experimental dosimetry of brachytherapy sources presents a challenge. Depending on the particular-dosimeter used, measurements can suffer from poor spatial resolution (ion chambers), lack of 3D information (film) or errors due to the presence of the dosimeter itself distorting the radiation f...

journal_title：Physics in medicine and biology

authors： McJury M,Tapper PD,Cosgrove VP,Murphy PS,Griffin S,Leach MO,Webb S,Oldham M

更新日期：1999-10-01 00:00:00

abstract：:Stopping power data for protons in tissue-equivalent gas (64.4% CH4 + 32.4% CO2 + 3.2% N2, partial pressures) were derived from experimentally determined ranges and from differential ionisation distributions using the differential energy required per ion pair formed to convert ionisation to energy loss. The proton ene...

journal_title：Physics in medicine and biology

authors： Waibel E,Willems G

更新日期：1987-03-01 00:00:00

abstract：:Kilovoltage intratreatment monitoring (KIM) is a novel real-time localization modality where the tumor position is continuously measured during intensity modulated radiation therapy (IMRT) or intensity modulated arc therapy (IMAT) by a kilovoltage (kV) x-ray imager. Adding kV imaging during therapy adds radiation dose...

journal_title：Physics in medicine and biology

authors： Ng JA,Booth J,Poulsen P,Kuncic Z,Keall PJ

更新日期：2013-09-07 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：:Compartmental models are widely used for the mathematical modelling of dynamic studies acquired with positron emission tomography (PET). The numerical problem involves the estimation of a sum of decaying real exponentials convolved with an input function. In exponential spectral analysis (SA), the nonlinear estimation...

journal_title：Physics in medicine and biology

authors： Turkheimer FE,Hinz R,Gunn RN,Aston JA,Gunn SR,Cunningham VJ

更新日期：2003-12-07 00:00:00

abstract：:In x-ray based imaging of the breast, contrast between fibroglandular (Fg) tissue and adipose (Ad) tissue is a source of anatomic noise. The goal of this work was to validate by simulation and experiment a mathematical framework for modelling the Fg component of anatomic noise in digital mammograpy (DM) and dual-energ...

journal_title：Physics in medicine and biology

authors： Tanguay J,Lalonde R,Bjarnason TA,Yang CJ

更新日期：2019-10-23 00:00:00

abstract：:This paper addresses fundamental issues that underlie the interpretation of images acquired from turbid tissues by optical-coherence tomography (OCT). The attenuation and backscattering properties of freshly excised rat arteries and their dependence on the focusing and collection optics of the OCT system were measured...

journal_title：Physics in medicine and biology

authors： Schmitt JM,Knüttel A,Yadlowsky M,Eckhaus MA

更新日期：1994-10-01 00:00:00

abstract：:Various lead attenuation techniques to determine the fast neutron sensitivity kU of a photon dosemeter are reviewed and a modified method is proposed to determine the kU value of a commercially available Geiger--Müller detector. The dependence on the 'effective' photon energy of the gamma-component of the mixed n--gam...

journal_title：Physics in medicine and biology

authors： Hough JH

更新日期：1979-07-01 00:00:00

abstract：:The established theory for the collection efficiency of an ionisation chamber irradiated by a series of uniform short pulses is extended to the more complex case of irradiation in a pulsed and electromagnetically swept electron beam. The radial variation of exposure rate is assumed to be Gaussian with scale constant e...

journal_title：Physics in medicine and biology

authors： Boag JW

更新日期：1982-02-01 00:00:00