A comprehensive study of the use of temporal moments in time-resolved diffuse optical tomography: part I. Theoretical material.

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：:Energy and spatial projection distributions were simulated for gamma camera imaging of multiple order Compton scattered photons. SPECT imaging of a line source of radioactivity located in a water filled cylindrical phantom was modelled using Monte Carlo techniques. Photon trajectories were followed from emission to de...

journal_title：Physics in medicine and biology

authors： Floyd CE,Jaszczak RJ,Harris CC,Coleman RE

更新日期：1984-10-01 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：:Monte Carlo (MC) algorithms are recognized as the most accurate methodology for patient dose assessment. For intensity-modulated radiation therapy (IMRT) delivered with dynamic multileaf collimators (DMLCs), accurate dose calculation, even with MC, is challenging. Accurate IMRT MC dose calculations require inclusion o...

journal_title：Physics in medicine and biology

authors： Siebers JV,Keall PJ,Kim JO,Mohan R

更新日期：2002-09-07 00:00:00

abstract：:This study presents a theoretical approach to the dosimetry for small and non-equilibrium radiation fields. We applied the newly developed VMCBC algorithm to the dosimetry for megavoltage photon beams using Monte Carlo techniques. The approach assumes that a Monte Carlo simulated beam can be calibrated per incident pa...

journal_title：Physics in medicine and biology

authors： Ding GX,Duggan DM,Coffey CW

更新日期：2008-07-07 00:00:00

abstract：:A correction for loss of events due to dead time in dynamic positron emission tomography (PET) is presented. The model employs a paralysing dead time to describe the behaviour of a tomograph over the range of event rates normally encountered in patient studies (up to 200 000 events/s per detector layer). The Donner 28...

journal_title：Physics in medicine and biology

authors： Mazoyer BM,Roos MS,Huesman RH

更新日期：1985-05-01 00:00:00

abstract：:To address the quality assurance (QA) of a MR-linac which is an MRI combined with a linear accelerator (linac), the traditional linac QA-tests need to be redesigned, since the presence of the static magnetic field in the MR-linac alters the electron trajectory. The latter causes the asymmetry in the dose kernel which ...

journal_title：Physics in medicine and biology

authors： van Zijp HM,van Asselen B,Wolthaus JW,Kok JM,de Vries JH,Ishakoglu K,Beld E,Lagendijk JJ,Raaymakers BW

更新日期：2016-02-07 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：:We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed an...

journal_title：Physics in medicine and biology

authors： Kim JH,Nuyts J,Kyme A,Kuncic Z,Fulton R

更新日期：2015-03-07 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：:Assessment of radiation absorbed dose to internal organs of the body from the intake of radionuclides or, in the medical setting through the injection of radiopharmaceuticals, is generally performed based upon reference biokinetic models or patient imaging data, respectively. Biokinetic models estimate the time course...

journal_title：Physics in medicine and biology

authors： Schwarz BC,Godwin WJ,Wayson MB,Dewji SA,Jokisch DW,Lee C,Bolch WE

更新日期：2020-11-03 00:00:00

abstract：:The accuracy of delivered radiation dose and the reproducibility of employed radiotherapy methods are key factors for preclinical radiobiology applications and research studies. In this work, ionization chamber (IC) measurements and Monte Carlo (MC) simulations were used to accurately determine the dose rate for total...

journal_title：Physics in medicine and biology

authors： Zhong Y,Lai Y,Saha D,Story MD,Jia X,Stojadinovic S

更新日期：2020-09-08 00:00:00

abstract：:The development of new biological imaging technologies offers the opportunity to further individualize radiotherapy. Biologically conformal radiation therapy (BCRT) implies the use of the spatial distribution of one or more radiobiological parameters to guide the IMRT dose prescription. Our aim was to implement BCRT i...

journal_title：Physics in medicine and biology

authors： Vanderstraeten B,De Gersem W,Duthoy W,De Neve W,Thierens H

更新日期：2006-08-21 00:00:00

abstract：:In order (i) to evaluate the dose uncertainty of the mouthpiece in daily use during intensity-modulated radiotherapy of patients with head and neck cancer, and (ii) to present a system for in vivo dosimetry of the oral mucosa, we equipped the mouthpiece with alanine dosimeter probes for in vivo dosimetry. The aim was ...

journal_title：Physics in medicine and biology

authors： Wagner D,Anton M,Vorwerk H

更新日期：2011-03-07 00:00:00

abstract：:Approximately 70% of acute coronary artery disease is caused by unstable (vulnerable) plaques with an inflammation of the overlying cap and high lipid content. A rupturing of the inflamed cap of the plaque results in propagation of the thrombus into the lumen, blockage of the artery and acute ischaemic syndrome or sud...

journal_title：Physics in medicine and biology

authors： Shikhaliev PM,Xu T,Ducote JL,Easwaramoorthy B,Mukherjee J,Molloi S

更新日期：2006-02-21 00:00:00

abstract：:Earlier work on the dielectric properties of cryoprotectant agents is extended using a modified measuring cell and method of data reduction yielding results more efficiently over a temperature range from -75 to +25 degrees C at frequencies from 27 MHz to 3 GHz. Dimethyl sulphoxide and butanediol are investigated at lo...

journal_title：Physics in medicine and biology

authors： Evans S,bin Azeman A

更新日期：1998-10-01 00:00:00

abstract：:The quantification of tumor motion in sites affected by respiratory motion is of primary importance to improve treatment accuracy. To account for motion, different studies analyzed the translational component only, without focusing on the rotational component, which was quantified in a few studies on the prostate with...

journal_title：Physics in medicine and biology

authors： Paganelli C,Lee D,Greer PB,Baroni G,Riboldi M,Keall P

更新日期：2015-09-21 00:00:00

abstract：:A system is described in which large superficial areas of tissue may be heated using a single plane ultrasonic transducer scanned in a raster fashion. The shape of the heated area is determined by the movement of a microswitch which is activated when it strikes the rigid edge of a hole of the required shape cut in a p...

journal_title：Physics in medicine and biology

authors： ter Haar G,Hopewell JW

更新日期：1985-12-01 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：:In recent years, the Monte Carlo method has been used in a large number of research studies in radiation therapy. For applications such as treatment planning, it is essential to validate the dosimetric accuracy of the Monte Carlo simulations in heterogeneous media. The AAPM Report no 105 addresses issues concerning cl...

journal_title：Physics in medicine and biology

authors： Titt U,Sahoo N,Ding X,Zheng Y,Newhauser WD,Zhu XR,Polf JC,Gillin MT,Mohan R

更新日期：2008-08-21 00:00:00

abstract：:Dose calculations were performed for a tissue phantom irradiated by uniform circular beams of negative pions with an assumed gaussian momentum distribution. The mean momentum of the pions was varied from 104.4 to 171.5 MeV/c (mean range 5-20 cm in unit-density tissue) and the momentum spread from 0 to 5% of the mean. ...

journal_title：Physics in medicine and biology

authors： Hamm RN,Wright HA,Turner JE

更新日期：1979-05-01 00:00:00

abstract：:Despite the early recognition of the potential of proton imaging to assist proton therapy (Cormack 1963 J. Appl. Phys. 34 2722), the modality is still removed from clinical practice, with various approaches in development. For proton-counting radiography applications such as computed tomography (CT), the water-equival...

journal_title：Physics in medicine and biology

authors： Poludniowski G,Allinson NM,Anaxagoras T,Esposito M,Green S,Manolopoulos S,Nieto-Camero J,Parker DJ,Price T,Evans PM

更新日期：2014-06-07 00:00:00

abstract：:State of the art point-spread function (PSF) corrections implemented in positron emission tomography/computed tomography (PET/CT) reconstruction improved image quality and diagnostic performance but caused an increase in the standardized uptake value (SUV) compared to a conventional OSEM reconstruction system. The EAN...

journal_title：Physics in medicine and biology

authors： Ferretti A,Chondrogiannis S,Rampin L,Bellan E,Marzola MC,Grassetto G,Gusella S,Maffione AM,Gava M,Rubello D

更新日期：2018-11-26 00:00:00

abstract：:Sparse phased array ultrasound transducers with millimetre length scale elements have previously been proposed for generating hyperthermia but not for imaging. Numerical simulation with a pseudospectral solver was used to investigate: (a) how the position of the maximum pressure in the focal region changed with elemen...

journal_title：Physics in medicine and biology

authors： Wilson AJ

更新日期：2018-07-16 00:00:00

abstract：:A hybrid differential and spatially resolved spectroscopy (SRS) technique has been developed to measure absolute absorption coefficient (mu(a)), reduced scattering coefficient (mu'(s)) and cerebral blood volume (CBV) in the adult human head. A spectrometer with both differential and SRS capabilities has been used to c...

journal_title：Physics in medicine and biology

authors： Leung TS,Tachtsidis I,Smith M,Delpy DT,Elwell CE

更新日期：2006-02-07 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：:Simultaneous dual-radionuclide myocardial perfusion/innervation SPECT imaging can provide important information about the mismatch between scar tissue and denervated regions. The Siemens IQ-SPECT system developed for cardiac imaging uses a multifocal SMARTZOOM collimator to achieve a four-fold sensitivity for the card...

journal_title：Physics in medicine and biology

authors： Du Y,Bhattacharya M,Frey EC

更新日期：2014-06-07 00:00:00

abstract：:Determining plaque vulnerability is critical when selecting the most suitable treatment for patients with atherosclerotic plaque. Currently, clinical non-invasive ultrasound-based methods for plaque characterization are limited to visual assessment of plaque morphology and new quantitative methods are needed. In this ...

journal_title：Physics in medicine and biology

authors： Widman E,Maksuti E,Larsson D,Urban MW,Bjällmark A,Larsson M

更新日期：2015-04-21 00:00:00

abstract：:This paper describes the development and characterization of a fully automated in vitro cell irradiator using an electronic brachytherapy source to perform radiation sensitivity bioassays. This novel irradiator allows complex variable dose and dose rate schemes to be delivered to multiple wells of 96-well culture plat...

journal_title：Physics in medicine and biology

authors： Fowler TL,Fulkerson RK,Micka JA,Kimple RJ,Bednarz BP

更新日期：2014-03-21 00:00:00

abstract：:This paper evaluates the performance of two large-area position-sensitive solid-state photomultipliers (PS-SSPM) for use in small animal PET detector designs. Both PS-SSPM device designs are 1 cm² in area, the first being a 2 × 2 tiled array of 5 mm × 5 mm PS-SSPMs and the second being a 10 mm × 10 mm continuous PS-SS...

journal_title：Physics in medicine and biology

authors： Schmall JP,Du J,Yang Y,Dokhale PA,McClish M,Christian J,Shah KS,Cherry SR

更新日期：2012-12-21 00:00:00