Scatter compensation methods in 3D iterative SPECT reconstruction: a simulation study.

abstract：:Chronic liver disease (CLD) is currently one of the major causes of death worldwide. If not treated, it may lead to cirrhosis, hepatic carcinoma and death. Ultrasound (US) shear wave elastography (SWE) is a relatively new, popular, non-invasive technique among radiologists. Although many studies have been published va...

journal_title：Physics in medicine and biology

authors： Kagadis GC,Drazinos P,Gatos I,Tsantis S,Papadimitroulas P,Spiliopoulos S,Karnabatidis D,Theotokas I,Zoumpoulis P,Hazle JD

更新日期：2020-11-05 00:00:00

abstract：:The purpose of this work is to develop a validated Geant4 simulation model of a whole-body prototype PET scanner constructed from the four-layer depth-of-interaction detectors developed at the National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Japan. T...

journal_title：Physics in medicine and biology

authors： Ahmed AM,Chacon A,Rutherford H,Akamatsu G,Mohammadi A,Nishikido F,Tashima H,Yoshida E,Yamaya T,Franklin DR,Rosenfeld A,Guatelli S,Safavi-Naeini M

更新日期：2020-12-18 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：:We investigate the effect of multiple scattering on the optical coherence tomography (OCT) signal and the Doppler OCT signal of flowing blood. Doppler OCT measurements at 1300 nm are performed on flowing diluted porcine blood with hematocrit ranging between 0% and 15%. Measured blood hematocrit and mean red blood cell...

journal_title：Physics in medicine and biology

authors： Kalkman J,Bykov AV,Streekstra GJ,van Leeuwen TG

更新日期：2012-04-07 00:00:00

abstract：:The bone suppression technique based on advanced image processing can suppress the conspicuity of bones on chest radiographs, creating soft tissue images obtained by the dual-energy subtraction technique. This study was performed to evaluate the usefulness of bone suppression image processing in image-guided radiation...

journal_title：Physics in medicine and biology

authors： Tanaka R,Sanada S,Sakuta K,Kawashima H

更新日期：2015-05-21 00:00:00

abstract：:The temperature sensitivities of absorption and reduced scattering coefficients in the range 700-1000 nm are determined for the liquid phantom Intralipid using spatially resolved continuous wave measurements. The measurements were conducted on a 10 L heated volume of 1% Intralipid subjected to a 40-30 degrees C coolin...

journal_title：Physics in medicine and biology

authors： McGlone VA,Martinsen P,Künnemeyer R,Jordan B,Cletus B

更新日期：2007-05-07 00:00:00

abstract：:Andreo and Benmakhlouf (2017 Phys. Med. Biol. 62 1518-32) have disputed a finding of Scott et al (2012 Phys. Med. Biol. 57 4461-76) that the variation with field-size of the response of small ion chambers and solid-state dosimeters in small megavoltage photon radiation fields can largely be attributed to density. Furt...

journal_title：Physics in medicine and biology

authors： Fenwick JD,Georgiou G,Rowbottom CG,Underwood TSA,Kumar S

更新日期：2018-10-03 00:00:00

abstract：:Time- and space-resolved diffuse reflectance measurements were used to identify the optical parameters, the reduced scattering and absorption coefficients, of bulk living tissue in the region from 1.15 to 1.52 microm. Although in this region the detector was limited in its temporal resolution, we applied a peak-time s...

journal_title：Physics in medicine and biology

authors： Nishimura G,Kida I,Tamura M

更新日期：2006-06-07 00:00:00

abstract：:Modern digital radiographic 'flat panel' detectors can exhibit a progressive form of image degradation arising from non-functioning pixels. The effect of these 'dead pixels' on the quantitive image quality measures of modulation transfer function (MTF), noise power spectrum (NPS) and detective quantum efficiency (DQE)...

journal_title：Physics in medicine and biology

authors： Padgett R,Kotre CJ

更新日期：2004-03-21 00:00:00

abstract：:All dosimetry protocols recommend the use of plane-parallel chambers for dose determination in electron beams with energies below 10-15 MeV. The protocols have assumed chamber perturbation effects to be negligible. The new AAPM Protocol (TG39) includes a cavity replacement factor prepl that differs from unity for some...

journal_title：Physics in medicine and biology

authors： Nilsson B,Montelius A,Andreo P

更新日期：1996-04-01 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：:This paper explores fast reconstruction strategies for 3D time-of-flight (TOF) positron emission tomography (PET), based on 2D data rebinning. Starting from pre-corrected 3D TOF data, a rebinning algorithm estimates for each transaxial slice the 2D TOF sinogram that would have been acquired by a single-ring scanner. T...

journal_title：Physics in medicine and biology

authors： Defrise M,Casey ME,Michel C,Conti M

更新日期：2005-06-21 00:00:00

abstract：:This paper describes the algorithm and examines the performance of an intensity-modulated radiation therapy (IMRT) beam-angle optimization (BAO) system. In this algorithm successive sets of beam angles are selected from a set of predefined directions using a fast simulated annealing (FSA) algorithm. An IMRT beam-profi...

journal_title：Physics in medicine and biology

authors： Djajaputra D,Wu Q,Wu Y,Mohan R

更新日期：2003-10-07 00:00:00

abstract：:Dual spectral computed tomography (DSCT) has a superior material distinguishability than the conventional single spectral computed tomography (SSCT). However, the decomposition process is an illposed problem, which is sensitive to noise. Thus, the decomposed image quality is degraded, and the corresponding signal-to-n...

journal_title：Physics in medicine and biology

authors： Wang Q,Zhu Y,Yu H

更新日期：2017-10-19 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：:In some medical procedures, it is difficult or impossible to maintain a line of sight for a guidance system. For such applications, people have begun to use electromagnetic trackers. Before a localizer can be effectively used for an image-guided procedure, a characterization of the localizer is required. The purpose o...

journal_title：Physics in medicine and biology

authors： Atuegwu NC,Galloway RL

更新日期：2008-08-21 00:00:00

abstract：:Temporal regularization plays a critical role in cardiac gated dynamic SPECT reconstruction, of which the goal is to obtain an image sequence from a single acquisition which simultaneously shows both cardiac motion and tracer distribution change over the course of imaging (termed 5D). In our recent work, we explored t...

journal_title：Physics in medicine and biology

authors： Niu X,Yang Y,King MA

更新日期：2012-09-07 00:00:00

abstract：:There are a number of gel dosimeter calibration methods in contemporary usage. The present study is a detailed Monte Carlo investigation into the accuracy of several calibration techniques. Results show that for most arrangements the dose to gel accurately reflects the dose to water, with the most accurate method invo...

journal_title：Physics in medicine and biology

authors： Taylor ML,Franich RD,Johnston PN,Millar RM,Trapp JV

更新日期：2007-07-07 00:00:00

abstract：:We are developing a dedicated, combined breast positron emission tomography (PET)-tomosynthesis scanner. Both the PET and digital breast tomosynthesis (DBT) scanners are integrated in a single gantry to provide spatially co-registered 3D PET-tomosynthesis images. The DBT image will be used to identify the breast bound...

journal_title：Physics in medicine and biology

authors： Krishnamoorthy S,Vent T,Barufaldi B,Maidment ADA,Karp JS,Surti S

更新日期：2020-10-28 00:00:00

abstract：:The x-ray exposure to patients has become a major concern in computed tomography (CT) and minimizing the radiation exposure has been one of the major efforts in the CT field. Due to plenty high-attenuation tissues in the human chest, under low-dose scan protocols, thoracic low-dose CT (LDCT) images tend to be severely...

journal_title：Physics in medicine and biology

authors： Chen Y,Yang Z,Hu Y,Yang G,Zhu Y,Li Y,Luo L,Chen W,Toumoulin C

更新日期：2012-05-07 00:00:00

abstract：:Silicon photomultipliers (SiPMs) are widely used in positron emission tomography (PET), however, SiPMs from different vendors vary in their performance characteristics. In addition, the specifications provided by the manufacturers are measured under different operating conditions and using different test setups, makin...

journal_title：Physics in medicine and biology

authors： Du J,Bai X,Cherry SR

更新日期：2019-08-07 00:00:00

abstract：:Uncertainties in determining clinically used relative biological effectiveness (RBE) values for ion beam therapy carry the risk of absolute and relative misestimations of RBE-weighted doses for clinical scenarios. This study assesses the consequences of hypothetical misestimations of input parameters to the RBE modell...

journal_title：Physics in medicine and biology

authors： Böhlen TT,Brons S,Dosanjh M,Ferrari A,Fossati P,Haberer T,Patera V,Mairani A

更新日期：2012-12-07 00:00:00

abstract：:This work presents an improvement of the VIPARnd ('nd' stands for 'normoxic, double', or VIP) polymer gel dosimeter. The gel composition was altered by increasing the concentration of the monomeric components, N-vinylpyrrolidone (NVP) and N,N'-methylenebisacrylamide (MBA), in co-solvent solutions. The optimal composit...

journal_title：Physics in medicine and biology

authors： Kozicki M,Jaszczak M,Maras P,Dudek M,Cłapa M

更新日期：2017-02-07 00:00:00

abstract：:We study the treatment plan optimization problem for volumetric modulated arc therapy (VMAT). We propose a new column-generation-based algorithm that takes into account bounds on the gantry speed and dose rate, as well as an upper bound on the rate of change of the gantry speed, in addition to MLC constraints. The alg...

journal_title：Physics in medicine and biology

authors： Peng F,Jia X,Gu X,Epelman MA,Romeijn HE,Jiang SB

更新日期：2012-07-21 00:00:00

abstract：:Positron range impairs resolution in PET imaging, especially for high-energy emitters and for small-animal PET. De-blurring in image reconstruction is possible if the blurring distribution is known. Furthermore, the percentage of annihilation events within a given distance from the point of positron emission is releva...

journal_title：Physics in medicine and biology

authors： Jødal L,Le Loirec C,Champion C

更新日期：2012-06-21 00:00:00

abstract：:We have numerically modelled the thermal effects of yellow (577 or 578 nm) light illumination on the ectatic blood vessels of port wine stains. We investigated the effect of the laser treatment parameters of light irradiance and illumination time on the extent of coagulation (coagulation thickness) of the endothelial ...

journal_title：Physics in medicine and biology

authors： Pickering JW,Butler PH,Ring BJ,Walker EP

更新日期：1989-09-01 00:00:00

abstract：:Proton beams used for radiotherapy will produce neutrons when interacting with matter. The purpose of this study was to quantify the equivalent dose to tissue due to secondary neutrons in pediatric and adult patients treated by proton therapy for brain lesions. Assessment of the equivalent dose to organs away from the...

journal_title：Physics in medicine and biology

authors： Zacharatou Jarlskog C,Lee C,Bolch WE,Xu XG,Paganetti H

更新日期：2008-02-07 00:00:00

abstract：:Motion-adaptive radiotherapy aims to deliver a conformal dose to the target tumour with minimal normal tissue exposure by compensating for tumour motion in real time. The prediction as well as the gating of respiratory motion have received much attention over the last two decades for reducing the targeting error of th...

journal_title：Physics in medicine and biology

authors： Bukhari W,Hong SM

更新日期：2015-01-07 00:00:00

abstract：:We examined the reasons for the reduction in response of a multidetector radiation counting system when operated at high count-rates and established a convenient method of correction which is accurate to within +/- 1% up to 0-6 X 10(5) counts per second. In its application the method uses the observed count-rates from...

journal_title：Physics in medicine and biology

authors： Oxby CB,Oldroyd B,Appleby DB

更新日期：1976-01-01 00:00:00

abstract：:A variable Jacobian and weighted backprojection algorithm, used for medical CT, was adapted to perform CT reconstructions on data obtained with a dental panoramic x-ray unit. A detector array, fitted to the unit for the purpose of acquiring digital panoramic radiographs, was used to collect the data. Compensations wer...

journal_title：Physics in medicine and biology

authors： Lee MD,Waggener RG,McDavid WD,Dove SB,Welander U,Tronje G

更新日期：1992-12-01 00:00:00