A beam profile generation algorithm for wedged half-beam blocked asymmetric fields.


:A method is presented to predict beam profiles and outputs for wedged asymmetric fields defined by independent collimator jaws allowing fast generation of beam profiles whilst requiring very little additional data to that already used by most treatment planning systems in generating symmetric field isodoses. Symmetric field data are modified by the use of wedged primary off-centre ratios (POCRS) which are obtained from in air measurements of the largest possible wedged field. Beam hardening occurring within the flattening filter and wedge is taken into account by the use of attenuation coefficients measured under each wedge and used to generate the wedged POCR at depth. A full investigation into the comparison between measured and calculated profiles was performed which demonstrates favourable agreement across the whole of the asymmetric field including the penumbra.


Phys Med Biol


Millin AE,Smith CW




Has Abstract


1994-01-01 00:00:00












  • Influence of source parameters on large-field electron beam profiles calculated using Monte Carlo methods.

    abstract::The purpose of this paper was to study the source model for a Monte Carlo simulation of electron beams from a medical linear accelerator. In a prior study, a non-divergent Gaussian source with a full-width at half-maximum (FWHM) of 0.15 cm was successful in predicting relative dose distributions for electron beams wit...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Weinberg R,Antolak JA,Starkschall G,Kudchadker RJ,White RA,Hogstrom KR

    更新日期:2009-01-07 00:00:00

  • Computational fluid dynamics modelling of perfusion measurements in dynamic contrast-enhanced computed tomography: development, validation and clinical applications.

    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

    pub_type: 杂志文章


    authors: Peladeau-Pigeon M,Coolens C

    更新日期:2013-09-07 00:00:00

  • Deformable and durable phantoms with controlled density of scatterers.

    abstract::We have developed deformable and durable optical tissue phantoms with a simple and well-defined microstructure including a novel combination of scatterers and a matrix material. These were developed for speckle and elastography investigations in optical coherence tomography, but should prove useful in many other field...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Bisaillon CE,Lamouche G,Maciejko R,Dufour M,Monchalin JP

    更新日期:2008-07-07 00:00:00

  • Extraction of the respiratory signal from small-animal CT projections for a retrospective gating method.

    abstract::We propose a retrospective respiratory gating algorithm to generate dynamic CT studies. To this end, we compared three different methods of extracting the respiratory signal from the projections of small-animal cone-beam computed tomography (CBCT) scanners. Given a set of frames acquired from a certain axial angle, su...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Chavarrías C,Vaquero JJ,Sisniega A,Rodríguez-Ruano A,Soto-Montenegro ML,García-Barreno P,Desco M

    更新日期:2008-09-07 00:00:00

  • A robust procedure for verifying TomoTherapy Hi-Art™ source models for small fields.

    abstract::The dosimetric measurement and modeling of small radiation treatment fields (<2 × 2 cm2) are difficult to perform and prone to error. Measurements of small fields are often adversely influenced by the properties of the detectors used to make them. The dosimetric properties of small fields have been difficult to accura...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Hundertmark B,Sterpin E,Mackie T

    更新日期:2011-06-21 00:00:00

  • In-bore setup and software for 3T MRI-guided transperineal prostate biopsy.

    abstract::MRI-guided prostate biopsy in conventional closed-bore scanners requires transferring the patient outside the bore during needle insertion due to the constrained in-bore space, causing a safety hazard and limiting image feedback. To address this issue, we present our custom-made in-bore setup and software to support M...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Tokuda J,Tuncali K,Iordachita I,Song SE,Fedorov A,Oguro S,Lasso A,Fennessy FM,Tempany CM,Hata N

    更新日期:2012-09-21 00:00:00

  • A unified analysis of FBP-based algorithms in helical cone-beam and circular cone- and fan-beam scans.

    abstract::A circular scanning trajectory is and will likely remain a popular choice of trajectory in computed tomography (CT) imaging because it is easy to implement and control. Filtered-backprojection (FBP)-based algorithms have been developed previously for approximate and exact reconstruction of the entire image or a region...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Pan X,Xia D,Zou Y,Yu L

    更新日期:2004-09-21 00:00:00

  • Block matching 3D random noise filtering for absorption optical projection tomography.

    abstract::Absorption and emission optical projection tomography (OPT), alternatively referred to as optical computed tomography (optical-CT) and optical-emission computed tomography (optical-ECT), are recently developed three-dimensional imaging techniques with value for developmental biology and ex vivo gene expression studies...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Fumene Feruglio P,Vinegoni C,Gros J,Sbarbati A,Weissleder R

    更新日期:2010-09-21 00:00:00

  • T1 and extracellular volume fraction mapping in cardiac magnetic resonance: estimation of accuracy and precision of a novel algorithm.

    abstract::Magnetic resonance imaging is effective for non-invasive detection of myocardial diseases by extracellular volume fraction (ECV) estimation. A new methodology for T1 and ECV mapping is tested in this work, comparing results with other well-consolidated methods. The associated level of uncertainty for data was also est...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Borrazzo C,Pacilio M,Galea N,Preziosi E,Carnì M,Francone M,Catalano C,Carbone I

    更新日期:2019-02-11 00:00:00

  • Alanine dosimetry in strong magnetic fields: use as a transfer standard in MRI-guided radiotherapy.

    abstract::Reference dosimetry in the presence of a strong magnetic field is challenging. Ionisation chambers have shown to be strongly affected by magnetic fields. There is a need for robust and stable detectors in MRI-guided radiotherapy (MRIgRT). This study investigates the behaviour of the alanine dosimeter in magnetic field...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Billas I,Bouchard H,Oelfke U,Shipley D,Gouldstone C,Duane S

    更新日期:2020-06-03 00:00:00

  • Diaphragm correction factors for free-air chamber standards for air kerma in x-rays.

    abstract::At present, only a correction factor for photon transmission, k(l), is systematically applied for the entrance diaphragm of free-air chamber standards for air kerma. In the present work, the Monte Carlo code PENELOPE is used to re-evaluate k(l) for the BIPM standards and new correction factors are calculated for photo...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Burns DT,Kessler C

    更新日期:2009-05-07 00:00:00

  • Contactless remote induction of shear waves in soft tissues using a transcranial magnetic stimulation device.

    abstract::This study presents the first observation of shear waves induced remotely within soft tissues. It was performed through the combination of a transcranial magnetic stimulation device and a permanent magnet. A physical model based on Maxwell and Navier equations was developed. Experiments were performed on a cryogel pha...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Grasland-Mongrain P,Miller-Jolicoeur E,Tang A,Catheline S,Cloutier G

    更新日期:2016-03-21 00:00:00

  • Characterization of a single LSO crystal layer high resolution research tomograph.

    abstract::The purpose of this study was to determine the performance of a single lutetium oxy-orthosilicate (LSO) crystal layer High Resolution Research Tomograph (HRRT) positron emission tomography (PET) scanner. The HRRT is a high resolution PET scanner designed for human brain and small animal imaging. The scanner consists o...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Boellaard R,Buijs F,de Jong HW,Lenox M,Gremillion T,Lammertsma AA

    更新日期:2003-02-21 00:00:00

  • An analysis of the accuracy of magnetic resonance flip angle measurement methods.

    abstract::Several methods of flip angle mapping for magnetic resonance imaging have been proposed. We evaluated the accuracy of five methods of flip angle measurement in the presence of measurement noise. Our analysis was performed in a closed form by propagation of probability density functions (PDFs). The flip angle mapping m...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Morrell GR,Schabel MC

    更新日期:2010-10-21 00:00:00

  • Analyses of multi-irradiation film for system alignments in stereotactic radiotherapy (SRT) and radiosurgery (SRS).

    abstract::In stereotactic radiosurgery, a seven-irradiation film was used to define any discrepancy between the beam and target centres. A mathematical model based on the linac alignment and target set-up was developed to diagnose the discrepancies of the seven-irradiation film between the beam and simulation target centres. Fr...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Tsai JS

    更新日期:1996-09-01 00:00:00

  • Examination of errors caused by random summing in in vivo prompt gamma ray analysis.

    abstract::A technique is described for examining the mode of operation of radiation detectors and estimating the losses and gains caused by random summing effects in spectra acquired at high counting rates. The technique is applied to estimating the errors caused by random summing when measuring the amounts of carbon and nitrog...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Yankuba S,Oldroyd B,Metcalfe SC,Godfrey JE,Oxby CB

    更新日期:1989-08-01 00:00:00

  • A convolution-subtraction scatter correction method for 3D PET.

    abstract::3D acquisition and reconstruction in positron emission tomography (PET) produce data with improved signal-to-noise ratios compared with conventional 2D slice-oriented methods. However, the sensitivity increase is accompanied by an increase in the number of scattered photons and random coincidences detected. This paper...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Bailey DL,Meikle SR

    更新日期:1994-03-01 00:00:00

  • A biological approach to the platelet survival curve with criticism of previous interpretations.

    abstract::The biological mechanisms of platelet destruction must be correctly identified before platelet survival curves can be interpreted. This report develops a theory of platelet destruction which is compared with experiments performed on platelets labelled with the radioactive isotope 51Cr. Platelet destruction rate is a c...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Trowbridge EA,Martin JF

    更新日期:1983-12-01 00:00:00

  • FPGA-based distributed coincidence processor for high count-rate online PET coincidence data acquisition.

    abstract::For PET online data acquisition, a centralized coincidence processor (CCP) with a single-thread data processing has been used to select coincidence events for many PET scanners. CCP has the advantage of highly integrated circuit, compact connection between detector front-end and system electronics, and centralized con...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Cheng X,Hu K,Yang D,Shao Y

    更新日期:2021-01-21 00:00:00

  • Direct 4D parametric imaging for linearized models of reversibly binding PET tracers using generalized AB-EM reconstruction.

    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

    pub_type: 杂志文章


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

    更新日期:2012-02-07 00:00:00

  • Experimental study on the influence of the central electrode in Farmer-type ionization chambers.

    abstract::In the IAEA TRS-381 protocol, k(cel) and p(cel) account for the central electrode perturbation during the air kerma chamber calibration and the in-phantom measurements. The values of these correction factors are based mainly on Monte Carlo simulations. In the present work experimental data on k(cel) and p(cel) for the...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Palm A,Mattsson O

    更新日期:1999-05-01 00:00:00

  • ALGEBRA: ALgorithm for the heterogeneous dosimetry based on GEANT4 for BRAchytherapy.

    abstract::Task group 43 (TG43)-based dosimetry algorithms are efficient for brachytherapy dose calculation in water. However, human tissues have chemical compositions and densities different than water. Moreover, the mutual shielding effect of seeds on each other (interseed attenuation) is neglected in the TG43-based dosimetry ...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Afsharpour H,Landry G,D'Amours M,Enger S,Reniers B,Poon E,Carrier JF,Verhaegen F,Beaulieu L

    更新日期:2012-06-07 00:00:00

  • Fibre-optic sensors in health care.

    abstract::Biomedical fibre-optic sensors are attractive for the measurement of physical, chemical and biochemical parameters and for spectral measurements directly performed on the patient. An overview of fibre-optic sensors for in vivo monitoring is given, with particular attention paid to the advantages that these sensors are...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章,评审


    authors: Mignani AG,Baldini F

    更新日期:1997-05-01 00:00:00

  • Specific absorbed fractions for a revised series of the UF/NCI pediatric reference phantoms: internal photon sources.

    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

    pub_type: 杂志文章


    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

  • Investigation of saddle trajectories for cardiac CT imaging in cone-beam geometry.

    abstract::This paper investigates cone-beam tomography for a wide class of x-ray source trajectories called saddles. In particular, a mathematical analysis of the number of intersections between a saddle and an arbitrary plane is given. This analysis demonstrates that axially truncated cone-beam projections acquired along a sad...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Pack JD,Noo F,Kudo H

    更新日期:2004-06-07 00:00:00

  • Dynamic (99m)Tc-MAG3 renography: images for quality control obtained by combining pharmacokinetic modelling, an anthropomorphic computer phantom and Monte Carlo simulated scintillation camera imaging.

    abstract::In dynamic renal scintigraphy, the main interest is the radiopharmaceutical redistribution as a function of time. Quality control (QC) of renal procedures often relies on phantom experiments to compare image-based results with the measurement setup. A phantom with a realistic anatomy and time-varying activity distribu...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Brolin G,Gleisner KS,Ljungberg M

    更新日期:2013-05-21 00:00:00

  • Tumour oxygen dynamics measured simultaneously by near-infrared spectroscopy and 19F magnetic resonance imaging in rats.

    abstract::Simultaneous near-infrared spectroscopy (NIRS) and magnetic resonance imaging (MRI) were used to investigate the correlation between tumour vascular oxygenation and tissue oxygen tension dynamics in rat breast 13762NF tumours with respect to hyperoxic gas breathing. NIRS directly detected global variations in the oxyg...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Xia M,Kodibagkar V,Liu H,Mason RP

    更新日期:2006-01-07 00:00:00

  • A high-sensitivity small animal SPECT system.

    abstract::Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) sy...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Mitchell GS,Cherry SR

    更新日期:2009-03-07 00:00:00

  • Fully 3D iterative scatter-corrected OSEM for HRRT PET using a GPU.

    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

    pub_type: 杂志文章


    authors: Kim KS,Ye JC

    更新日期:2011-08-07 00:00:00

  • Development of the complex permittivity measurement system for high-loss biological samples using the free space method in quasi-millimeter and millimeter wave bands.

    abstract::The free space method using a pair of lens antennas was modified for the complex permittivity measurement of biological samples from 20 to 110 GHz. Two methodologies were used to obtain the complex permittivities by the free space method, which were based on the reflection and transmission coefficients. The measuremen...

    journal_title:Physics in medicine and biology

    pub_type: 杂志文章


    authors: Sasaki K,Segawa H,Mizuno M,Wake K,Watanabe S,Hashimoto O

    更新日期:2013-03-07 00:00:00