Comparison of 3D-OP-OSEM and 3D-FBP reconstruction algorithms for High-Resolution Research Tomograph studies: effects of randoms estimation methods.

abstract：:The purpose of this paper for four-dimensional (4D) computed tomography (CT) is threefold. (1) A new spatiotemporal model is presented from the matrix perspective with the row dimension in space and the column dimension in time, namely the robust PCA (principal component analysis)-based 4D CT model. That is, instead o...

journal_title：Physics in medicine and biology

authors： Gao H,Cai JF,Shen Z,Zhao H

更新日期：2011-06-07 00:00:00

abstract：:The coincidence time resolution (CTR) becomes a key parameter of 511 keV gamma detection in time of flight positron emission tomography (TOF-PET). This is because additional information obtained through timing leads to a better noise suppression and therefore a better signal to noise ratio in the reconstructed image. ...

journal_title：Physics in medicine and biology

authors： Nemallapudi MV,Gundacker S,Lecoq P,Auffray E,Ferri A,Gola A,Piemonte C

更新日期：2015-06-21 00:00:00

abstract：:In this paper we describe measurements of the contrast transfer function, modulation transfer function and point-spread function of an optical coherence tomography (OCT) imaging system through scattering layers having a dimension-less scattering depth over the range 0.2-6.9. The results were found to be insensitive to...

journal_title：Physics in medicine and biology

authors： Woolliams PD,Tomlins PH

更新日期：2011-05-07 00:00:00

abstract：:We present a comparison of simulated low-frequency electromagnetic fields in the human body, calculated by means of the electro-quasistatic formulation. The geometrical data in these simulations were provided by an anatomically realistic, high-resolution human body model, while the dielectric properties of the various...

journal_title：Physics in medicine and biology

authors： Barchanski A,De Gersem H,Gjonaj E,Weiland T

更新日期：2005-10-07 00:00:00

abstract：:We recently started orthogonal two-port carbon ion therapy for choroidal melanoma with the intent to reduce the incidence of radiation complications that occur with mono-port therapy. Treatment planning techniques involving therapeutic beam characteristics are described here. The vertical (140 MeV/u) and horizontal (1...

journal_title：Physics in medicine and biology

authors： Koyama-Ito H,Kanai T,Minohara S,Tsuji H,Tsujii H

更新日期：2007-09-07 00:00:00

abstract：:A clinical trial named PROMETHEUS is currently ongoing for inoperable hepatocellular carcinoma (HCC) at the Heidelberg Ion Beam Therapy Center (HIT, Germany). In this framework, 4D PET-CT datasets are acquired shortly after the therapeutic treatment to compare the irradiation induced PET image with a Monte Carlo PET p...

journal_title：Physics in medicine and biology

authors： Gianoli C,Kurz C,Riboldi M,Bauer J,Fontana G,Baroni G,Debus J,Parodi K

更新日期：2016-06-07 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：:Four dimensional cone beam computed tomography (4DCBCT) uses a constant gantry speed and imaging frequency that are independent of the patient's breathing rate. Using a technique called respiratory motion guided 4DCBCT (RMG-4DCBCT), we have previously demonstrated that by varying the gantry speed and imaging frequency...

journal_title：Physics in medicine and biology

authors： O'Brien RT,Stankovic U,Sonke JJ,Keall PJ

更新日期：2017-06-07 00:00:00

abstract：:A theoretical analysis is presented of the biologically effective dose of the solar long wave ultraviolet radiation (UVA) received by patients who are being treated for psoriasis by oral psoralen photochemotherapy. It is shown that patients treated during the summer months in the UK may well receive a UV dose which is...

journal_title：Physics in medicine and biology

authors： Diffey BL

更新日期：1981-11-01 00:00:00

abstract：:For medical applications of ultrasound inside the brain, it is necessary to understand the relationship between the apparent density of skull bone and its corresponding speed of sound and attenuation coefficient. Although there have been previous studies exploring this phenomenon, there is still a need to extend the m...

journal_title：Physics in medicine and biology

authors： Pichardo S,Sin VW,Hynynen K

更新日期：2011-01-07 00:00:00

abstract：:In positron emission tomography (PET) with pixelated detectors, a significant number of annihilation photons interact with scintillation crystals through single or multiple Compton scattering events. When these partial energy depositions occur across multiple crystal elements, we call them inter-crystal scatter (ICS) ...

journal_title：Physics in medicine and biology

authors： Park H,Lee JS

更新日期：2020-10-21 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：:Although not as widespread as Ir-192, Co-60 is also available on afterloading equipment devoted to high dose rate brachytherapy, mainly addressed to the treatment of gynaecological lesions. The purpose of this study is to obtain the dosimetric parameters of the Co-60 source used by the BEBIG MultiSource remote afterlo...

journal_title：Physics in medicine and biology

authors： Ballester F,Granero D,Pérez-Calatayud J,Casal E,Agramunt S,Cases R

更新日期：2005-11-07 00:00:00

abstract：:As the use of radiofrequency (RF) electromagnetic (EM) fields has increased along with increased use of wireless communication, the possible related health risks have also been widely discussed. One safety aspect is the interaction of medical implants and RF devices like mobile phones. In the literature, effects on ac...

journal_title：Physics in medicine and biology

authors： Virtanen H,Keshvari J,Lappalainen R

更新日期：2007-03-07 00:00:00

abstract：:This study aims to develop and test software for assessing and reporting doses for standard patients undergoing computed tomography (CT) examinations in a 320 detector-row cone-beam scanner. The software, called SimDoseCT, is based on the Monte Carlo (MC) simulation code, which was developed to calculate organ doses a...

journal_title：Physics in medicine and biology

authors： Cros M,Joemai RMS,Geleijns J,Molina D,Salvadó M

更新日期：2017-07-17 00:00:00

abstract：:Changes in the relative biological effectiveness (RBE) of the radiation-induced cell killing of human salivary glands (HSG) were assessed along the Bragg peak of a 60 MeV clinical proton beam by means of coupling biophysical models with the results of Monte Carlo radiation transport simulations and experimental measur...

journal_title：Physics in medicine and biology

authors： Parisi A,Olko P,Swakoń J,Horwacik T,Jabłoński H,Malinowski L,Nowak T,Struelens L,Vanhavere F

更新日期：2020-01-10 00:00:00

abstract：:Distributions of linear pathlength measurements have been utilized in skeletal dosimetry of internally emitted short-range particles for over 30 years. This work reviews the methods for coupling these distributions to range-energy data. A revised methodology is presented for handling the insertion of the additional do...

journal_title：Physics in medicine and biology

authors： Jokisch DW,Rajon DA,Patton PW,Bolch WE

更新日期：2011-05-07 00:00:00

abstract：:A formalism is proposed for the estimation of mean glandular dose for breast tomosynthesis, which is a simple extension of the UK, European and IAEA protocols for dosimetry in conventional projection mammography. The formalism introduces t-factors for the calculation of breast dose from a single projection and T-facto...

journal_title：Physics in medicine and biology

authors： Dance DR,Young KC,van Engen RE

更新日期：2011-01-21 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：:Voltage-sensitive dyes are an important tool in visualizing electrical activity in cardiac tissue. Until today, they have mainly been applied in cardiac electrophysiology to subsurface imaging. In the present study, we assess different imaging methods used in optical tomography with respect to their effectiveness in v...

journal_title：Physics in medicine and biology

authors： Bernus O,Wellner M,Mironov SF,Pertsov AM

更新日期：2005-01-21 00:00:00

abstract：:Respiratory-correlated cone-beam CT (CBCT) not only inhibits rapid scanning due to the slow speed of the LINAC head gantry rotation, but its implementation for routine patient imaging is impractical because of the high radiation dose delivered during the process. Digital tomosynthesis (DTS) is a potentially faster tec...

journal_title：Physics in medicine and biology

authors： Choi S,Lee S,Kang YN,Hsieh SS,Kim HJ

更新日期：2019-05-02 00:00:00

abstract：:In magnetic drug targeting a chemotherapeutic agent is bound to coated magnetic nanoparticles, which are administered to the blood vessel system and subsequently focused by an external applied magnetic field. The optimization of intra-arterial magnetic drug targeting (MDT) requires detailed knowledge about the biodist...

journal_title：Physics in medicine and biology

authors： Richter H,Wiekhorst F,Schwarz K,Lyer S,Tietze R,Alexiou Ch,Trahms L

更新日期：2009-09-21 00:00:00

abstract：:The measurement of output factors (OF) for the small photon beams generated by Leksell Gamma Knife® (LGK) radiotherapy units is a challenge for the physicist due to the under or over estimation of these factors by a vast majority of the detectors commercially available. Output correction factors, introduced in the int...

journal_title：Physics in medicine and biology

authors： Benmakhlouf H,Johansson J,Paddick I,Andreo P

更新日期：2015-05-21 00:00:00

abstract：:In charged particle therapy with pencil beam scanning (PBS), localization of the dose in the Bragg peak makes dose distributions sensitive to lateral tissue heterogeneities. The sensitivity of a PBS plan to lateral tissue heterogeneities can be reduced by selecting appropriate beam angles. The purpose of this study is...

journal_title：Physics in medicine and biology

authors： Toramatsu C,Inaniwa T

更新日期：2016-12-21 00:00:00

abstract：:Stereotactic Gamma Knife radiosurgery utilizes ionizing beams from (60)Co sources and relies on a combination of collimator sizes, weighting, etc to generate a high-dose region that is conformal with a designated target volume. Dose computation is typically performed by computer, but in this paper, single collimator d...

journal_title：Physics in medicine and biology

authors： Fenner J,Gwilliam M,Mehrem R,Bird A,Walton L

更新日期：2008-04-21 00:00:00

abstract：:A novel approach to read out radiochromic film was introduced recently by the manufacturer of GafChromic film. In this study, the performance of this triple-channel film dosimetry method was compared against the conventional single-red-channel film dosimetry procedure, with and without inclusion of a pre-irradiation (...

journal_title：Physics in medicine and biology

authors： van Hoof SJ,Granton PV,Landry G,Podesta M,Verhaegen F

更新日期：2012-07-07 00:00:00

abstract：:Due to high noise levels in the voxel kinetics, development of reliable parametric imaging algorithms remains one of most active areas in dynamic brain PET imaging, which in the vast majority of cases involves receptor/transporter studies with reversibly binding tracers. As such, the focus of this work has been to dev...

journal_title：Physics in medicine and biology

authors： Rahmim A,Zhou Y,Tang J,Lu L,Sossi V,Wong DF

更新日期：2012-02-07 00:00:00

abstract：:This study investigates the dosimetric impact of using population-based Hounsfield units (HUs) and ICRU-based HUs as a function of the number of tissue segments for bulk density assignment toward MRI-based treatment planning in the abdomen. To avoid potential geometric differences between CT and MR images, CT images r...

journal_title：Physics in medicine and biology

authors： Hsu SH,Zawisza I,O'Grady K,Peng Q,Tomé WA

更新日期：2018-07-24 00:00:00

abstract：:In this work we present the first delivery of intensity modulated arc therapy on the Elekta Unity 1.5 T MR-linac. The machine's current IMRT based control system was modified suitably to enable dynamic delivery of radiation, for the purpose of exploring MRI-guided radiation therapy adaptation modes in a research setti...

journal_title：Physics in medicine and biology

authors： Kontaxis C,Woodhead PL,Bol GH,Lagendijk JJW,Raaymakers BW

更新日期：2020-12-23 00:00:00

abstract：:Dynamic 18F-FDG PET with tracer kinetic modeling has the potential to noninvasively evaluate human liver inflammation using the FDG blood-to-tissue transport rate K 1. Accurate kinetic modeling of dynamic liver PET data and K 1 quantification requires the knowledge of dual-blood input function from the hepatic artery ...

journal_title：Physics in medicine and biology

authors： Zuo Y,Sarkar S,Corwin MT,Olson K,Badawi RD,Wang G

更新日期：2019-09-05 00:00:00