Comparison of Geant4 multiple Coulomb scattering models with theory for radiotherapy protons.

abstract：:A method to measure the detector-to-object distance from the images obtained with stationary high-spatial-resolution gamma-ray cameras for in vivo studies has been developed. It exploits the shift of the imaged object in the image plane, obtained at a certain tilt of the parallel-hole collimator. A linear dependence o...

journal_title：Physics in medicine and biology

authors： Uzunov N,Bello M,Boccaccio P,Moschini G,Bollini D,de Notaristefani F

更新日期：2006-05-07 00:00:00

abstract：:In modern radiotherapy, it is vitally important to monitor the performance of all linac components including the collimation system. In this study, a simple measurement method and accurate algorithm are introduced for investigation of the secondary and tertiary collimator sag during radiotherapy arc treatments. The me...

journal_title：Physics in medicine and biology

authors： Rowshanfarzad P,Sabet M,O'Connor DJ,Greer PB

更新日期：2012-06-21 00:00:00

abstract：:A new system has been designed and built to validate the concept of 3D computerized angiography (CA). This system can acquire a set of 2D digital subtracted angiography images while rotating around a patient and then, using these images, reconstruct a 3D representation of the opacified vasculature. The design principl...

journal_title：Physics in medicine and biology

authors： Saint-Félix D,Trousset Y,Picard C,Ponchut C,Roméas R,Rougée A

更新日期：1994-03-01 00:00:00

abstract：:Accurate scatter correction is especially important for high-resolution 3D positron emission tomographies (PETs) such as high-resolution research tomograph (HRRT) due to large scatter fraction in the data. To address this problem, a fully 3D iterative scatter-corrected ordered subset expectation maximization (OSEM) in...

journal_title：Physics in medicine and biology

authors： Kim KS,Ye JC

更新日期：2011-08-07 00:00:00

abstract：:Contrast-enhanced ultrasound (US) imaging is potentially applicable to the investigation of vascular disorders of the testis. We investigated the ability of two automated computer algorithms to analyse contrast-enhanced pulse inversion US data in a rabbit model of unilateral testicular ischaemia and to correctly deter...

journal_title：Physics in medicine and biology

authors： Thierman JS,Clement GT,Kalish LA,O'Kane PL,Frauscher F,Paltiel HJ

更新日期：2006-07-21 00:00:00

abstract：:This paper presents two 4D mathematical observer models for the detection of motion defects in 4D gated medical images. Their performance was compared with results from human observers in detecting a regional motion abnormality in simulated 4D gated myocardial perfusion (MP) SPECT images. The first 4D mathematical obs...

journal_title：Physics in medicine and biology

authors： Lee TS,Frey EC,Tsui BM

更新日期：2015-04-07 00:00:00

abstract：:Partial volume effects (PVEs) are consequences of the limited spatial resolution in emission tomography. They lead to a loss of signal in tissues of size similar to the point spread function and induce activity spillover between regions. Although PVE can be corrected for by using algorithms that provide the correct ra...

journal_title：Physics in medicine and biology

authors： Boussion N,Hatt M,Lamare F,Bizais Y,Turzo A,Cheze-Le Rest C,Visvikis D

更新日期：2006-04-07 00:00:00

abstract：:Scatter correction is an essential technique to improve the image quality of cone-beam CT (CBCT). Although different scatter correction methods have been proposed in the literature, a standard solution is still being studied due to the limitations including accuracy, computation efficiency and generalization. In this ...

journal_title：Physics in medicine and biology

authors： Jiang Y,Yang C,Yang P,Hu X,Luo C,Xue Y,Xu L,Hu X,Zhang L,Wang J,Sheng K,Niu T

更新日期：2019-07-11 00:00:00

abstract：:The quality of radiation therapy delivered for treating cancer patients is related to set-up errors and organ motion. Due to the margins needed to ensure adequate target coverage, many breast cancer patients have been shown to develop late side effects such as pneumonitis and cardiac damage. Breathing-adapted radiatio...

journal_title：Physics in medicine and biology

authors： Kakar M,Nyström H,Aarup LR,Nøttrup TJ,Olsen DR

更新日期：2005-10-07 00:00:00

abstract：:Target motion is one of the major limitations of each high precision radiation therapy. Using advanced active beam delivery techniques, such as the magnetic raster scanning system for particle irradiation, the interplay between time-dependent beam and target position heavily distorts the applied dose distribution. Thi...

journal_title：Physics in medicine and biology

authors： Li Q,Groezinger SO,Haberer T,Rietzel E,Kraft G

更新日期：2004-07-21 00:00:00

abstract：:Multileaf collimator (MLC) calibration and quality control is a time-consuming procedure typically involving the processing, scanning and analysis of films to measure leaf and collimator positions. Faster and more reliable calibration procedures are required for these tasks, especially with the introduction of intensi...

journal_title：Physics in medicine and biology

authors： Baker SJ,Budgell GJ,MacKay RI

更新日期：2005-04-07 00:00:00

abstract：:When dosimetric effects in time-dependent geometries are studied, usually either the results of individual three-dimensional (3D) calculations are combined or probability-based approaches are applied. These methods may become cumbersome and time-consuming if high time resolution is required or if the geometry is compl...

journal_title：Physics in medicine and biology

authors： Paganetti H,Jiang H,Trofimov A

更新日期：2005-03-07 00:00:00

abstract：:Several applications in nuclear medicine require absolute activity quantification of single photon emission computed tomography images. Obtaining a repeatable calibration factor that converts voxel values to activity units is essential for these applications. Because source preparation and measurement of the source ac...

journal_title：Physics in medicine and biology

authors： Anizan N,Wang H,Zhou XC,Wahl RL,Frey EC

更新日期：2015-02-07 00:00:00

abstract：:Delivery of pencil beam scanning (PBS) requires the on-line measurement of several beam parameters. If the measurement is outside of specified tolerances and a binary threshold algorithm is used, the beam will be paused. Given instrumentation and statistical noise such a system can lead to many pauses which could incr...

journal_title：Physics in medicine and biology

authors： Clasie BM,Kooy HM,Flanz JB

更新日期：2016-01-07 00:00:00

abstract：:Digital phantoms continue to play a significant role in modeling and characterizing medical imaging. The currently available XCAT phantom incorporates both the flexibility of mathematical phantoms and the realistic nature of voxelized phantoms. This phantom generates images based on a regular breathing pattern and can...

journal_title：Physics in medicine and biology

authors： Mishra P,St James S,Segars WP,Berbeco RI,Lewis JH

更新日期：2012-06-07 00:00:00

abstract：:The goal of this study was to determine the quantitative accuracy of our OSEM-APDI reconstruction method based on SPECT/CT imaging for Tc-99m, In-111, I-123, and I-131 isotopes. Phantom studies were performed on a SPECT/low-dose multislice CT system (Infinia-Hawkeye-4 slice, GE Healthcare) using clinical acquisition p...

journal_title：Physics in medicine and biology

authors： Shcherbinin S,Celler A,Belhocine T,Vanderwerf R,Driedger A

更新日期：2008-09-07 00:00:00

abstract：:The current UK code of practice for high-energy photon therapy dosimetry (Lillicrap et al 1990 Phys. Med. Biol. 35 1355-60) gives instructions for measuring absorbed dose to water under reference conditions for megavoltage photons. The reference conditions and the index used to specify beam quality require that a mach...

journal_title：Physics in medicine and biology

authors： Thomas SJ,Aspradakis MM,Byrne JP,Chalmers G,Duane S,Rogers J,Thomas RA,Tudor GS,Twyman N,IPEM Working Party.

更新日期：2014-03-21 00:00:00

abstract：:Radiobiological models for estimating normal tissue complication probability (NTCP) are increasingly used in order to quantify or optimize the clinical outcome of radiation therapy. A good NTCP model should fulfill at least the following two requirements: (a) it should predict the sigmoid shape of the corresponding do...

journal_title：Physics in medicine and biology

authors： Adamus-Górka M,Mavroidis P,Brahme A,Lind BK

更新日期：2008-11-21 00:00:00

abstract：:First experimental results with energy-resolved computed tomography (CT) are reported. The contrast-to-noise ratio (CNR) in CT has been improved with x-ray energy weighting for the first time. Further, x-ray energy weighting improved the CNR in material decomposition CT when applied to CT projections prior to dual-ene...

journal_title：Physics in medicine and biology

authors： Shikhaliev PM

更新日期：2008-10-21 00:00:00

abstract：:Prompt γ-ray imaging with a knife-edge shaped slit camera provides the possibility of verifying proton beam range in tumor therapy. Dedicated experiments regarding the characterization of the camera system have been performed previously. Now, we aim at implementing the prototype into clinical application of monitoring...

journal_title：Physics in medicine and biology

authors： Priegnitz M,Barczyk S,Nenoff L,Golnik C,Keitz I,Werner T,Mein S,Smeets J,Vander Stappen F,Janssens G,Hotoiu L,Fiedler F,Prieels D,Enghardt W,Pausch G,Richter C

更新日期：2016-11-21 00:00:00

abstract：:Three-dimensional reconstruction of cardiac vasculature from angiographic C-arm CT (rotational angiography) data is a major challenge. Motion artefacts corrupt image quality, reducing usability for diagnosis and guidance. Many state-of-the-art approaches depend on retrospective ECG-gating of projection data for image ...

journal_title：Physics in medicine and biology

authors： Schwemmer C,Rohkohl C,Lauritsch G,Müller K,Hornegger J

更新日期：2013-06-07 00:00:00

abstract：:Dynamic contrast-enhanced computed tomography (DCE-CT) is an imaging tool that aids in evaluating functional characteristics of tissue at different stages of disease management: diagnostic, radiation treatment planning, treatment effectiveness, and monitoring. Clinical validation of DCE-derived perfusion parameters re...

journal_title：Physics in medicine and biology

authors： Peladeau-Pigeon M,Coolens C

更新日期：2013-09-07 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：:A number of radiation-therapy-related uses based on a commercially available spreadsheet program have been developed at our facility. The graphics and display capabilities inherent in these spreadsheet programs allow for concise visual results. The spreadsheets are used as an independent check for several types of rad...

journal_title：Physics in medicine and biology

authors： Balog JP,Sibata CH,Podgorsak MB,Shin KH

更新日期：1995-06-01 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：:Evidence that some lung tumors change shape during respiration is derived from respiratory gated CT data by statistical shape modeling and image manipulation. Some tumors behave as rigid objects while others show systematic shape changes. Two views of lung motion are presented to allow analysis of the results. In the ...

journal_title：Physics in medicine and biology

authors： Kyriakou E,McKenzie DR

更新日期：2012-02-21 00:00:00

abstract：:It has been reported that the dose effects of metallic guidewires are significant in intravascular brachytherapy (IVBT) using a beta source. The purpose of this work is to investigate the dependence of these dose effects on guidewire position. The EGS4 Monte Carlo codes were used to perform the dose calculations for t...

journal_title：Physics in medicine and biology

authors： Shih R,Hsu WL,Li XA

更新日期：2002-05-21 00:00:00

abstract：:The metabolic content of urine from NIH III nude mice (n = 22) was analysed before and after inoculation with human glioblastoma multiforme (GBM) cancer cells. An age- and gender-matched control population (n = 14) was also studied to identify non-tumour-related changes. Urine samples were collected daily for 6 weeks,...

journal_title：Physics in medicine and biology

authors： Moroz J,Turner J,Slupsky C,Fallone G,Syme A

更新日期：2011-02-07 00:00:00

abstract：:Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better or...

journal_title：Physics in medicine and biology

authors： Rocha H,Dias JM,Ferreira BC,Lopes MC

更新日期：2013-05-07 00:00:00

abstract：:The device developed by the authors and described here enables the user to measure the depth from the water surface to the point of measurement for a cylindrical ion chamber with a waterproof plastic cap in a water phantom, free of surface-tension error with a high precision. The device seeks vertical orientation and ...

journal_title：Physics in medicine and biology

authors： Tailor RC,Tello VM

更新日期：1995-08-01 00:00:00