Application of the convolution method for calculation of output factors for therapy photon beams.

abstract：PURPOSE:Potential collision between the patient∕couch and the gantry could delay the start of the treatment and reduce clinical efficiency. The ability to accurately detect possible collisions during the treatment planning phase is desired. Such collision detection should account for the specific proton gantry design, ...

journal_title：Medical physics

authors： Zou W,Lin H,Plastaras JP,Wang H,Bui V,Vapiwala N,McDonough J,Tochner Z,Both S

更新日期：2012-11-01 00:00:00

abstract：:Current generation electronic portal imaging devices (EPID) contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When using these EPIDs for low-Z target imaging, the conversion plate largely attenuates the large populations of diagnostic energy photons, there...

journal_title：Medical physics

authors： Parsons D,Robar JL

更新日期：2012-07-01 00:00:00

abstract：:In this work, the authors have evaluated ten different ionization chambers for the relative dosimetry of kilovoltage x-ray beams in the energy range of 50-280 kVp. Percentage depth doses in water and relative detector response (in Solid Water and in air) were measured for each of the x-ray beams studied using a number...

journal_title：Medical physics

authors： Hill R,Mo Z,Haque M,Baldock C

更新日期：2009-09-01 00:00:00

abstract：:The dose-rate dependence of commercially available diode detectors was measured under both high instantaneous dose-rate (pulsed) and low dose rate (continuous, Co-60) radiation. The dose-rate dependence was measured in an acrylic miniphantom at a 5-cm depth in a 10 x 10 cm2 collimator setting, by varying source-to-det...

journal_title：Medical physics

authors： Saini AS,Zhu TC

更新日期：2004-04-01 00:00:00

abstract：:The physical factors that govern 2D and 3D imaging performance may be understood from quantitative analysis of the spatial-frequency-dependent signal and noise transfer characteristics [e.g., modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta...

journal_title：Medical physics

authors： Tward DJ,Siewerdsen JH

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:For stereotactic radiosurgery (SRS), accurate evaluation of dose-volume metrics for small structures is necessary. The purpose of this study was to compare the DVH metric capabilities of five commercially available SRS DVH analysis tools (Eclipse, Elements, Raystation, MIM, and Velocity). METHODS:DICOM RTdose ...

journal_title：Medical physics

authors： Stanley DN,Covington E,Liu H,Alexandrian A,Cardan R,Bridges D,Thomas EM,Fiveash JB,Popple R

更新日期：2020-12-09 00:00:00

abstract：PURPOSE:In this work, the authors introduce a novel framework, the anatomically constrained registration (AnCoR) scheme and apply it to create a fused anatomic-disease atlas of the prostate which the authors refer to as the prostatome. The prostatome combines a MRI based anatomic and a histology based disease atlas. St...

journal_title：Medical physics

authors： Rusu M,Bloch BN,Jaffe CC,Genega EM,Lenkinski RE,Rofsky NM,Feleppa E,Madabhushi A

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:To investigate how the setting of optimization parameters, fractional dose and tuning structure in tomotherapy treatment planning affects plan dosimetric quality and treatment efficiency. METHODS:A digital phantom to simulate head and neck radiotherapy was constructed for this study. Tumor was 10cm long C-shap...

journal_title：Medical physics

authors： Lian J,Burkhardt K,Chera B,Chang S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Diabetic retinopathy (DR) is one of the most widespread causes of preventable blindness in the world. The most dangerous stage of this condition is proliferative DR (PDR), in which the risk of vision loss is high and treatments are less effective. Fractal features of the retinal vasculature have been previously...

journal_title：Medical physics

authors： Orlando JI,van Keer K,Barbosa Breda J,Manterola HL,Blaschko MB,Clausse A

更新日期：2017-12-01 00:00:00

abstract：:The Gafchromic EBT was recently introduced in film dosimetry for external beam therapy (EBT). The high spatial resolution, weak energy dependence, and near-tissue equivalence of EBT films make them suitable for measurement of dose distributions in radiotherapy, especially intensity-modulated radiation therapy (IMRT). ...

journal_title：Medical physics

authors： Fiandra C,Ricardi U,Ragona R,Anglesio S,Giglioli FR,Calamia E,Lucio F

更新日期：2006-11-01 00:00:00

abstract：PURPOSE:Carpal tunnel syndrome (CTS) is the common entrapment neuropathy that occurs due to compression of the median nerve at the wrist. Ultrasound images have been used to highlight anatomical variants of the median nerve, and CTS is thought to be associated to enlargement of the cross-sectional area (CSA) of the med...

journal_title：Medical physics

authors： Liao YY,Wu CC,Kuo TT,Chen JP,Hsu YW,Yeh CK

更新日期：2012-12-01 00:00:00

abstract：PURPOSE:Quantification of body composition plays an important role in many clinical and research applications. Radiologic imaging techniques such as Dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) imaging make accurate quantification of the body composition possibl...

journal_title：Medical physics

authors： Liu T,Udupa JK,Miao Q,Tong Y,Torigian DA

更新日期：2019-03-01 00:00:00

abstract：PURPOSE:To introduce a pair of accelerated non-Cartesian acquisition principles that when combined, exploit the periodicity of k-space acquisition, and thereby enable acquisition of high-temporal cine Cardiac Magnetic Resonance (CMR). METHODS:The mathematical formulation of a noniterative, undersampled non-Cartesian c...

journal_title：Medical physics

authors： Kawaji K,Patel MB,Cantrell CG,Tanaka A,Marino M,Tamura S,Wang H,Wang Y,Carroll TJ,Ota T,Patel AR

更新日期：2017-07-01 00:00:00

abstract：:The line spread function (LSF) of an imaging system incorporating a pinhole of 0.275 cm radius and a scintillation camera has been measured and its full width at half maximum (FWHM) compared to the values predicted by an expression based on the resolution index of Anger. In most cases, the actual resolution of the sys...

journal_title：Medical physics

authors： Goulet P,Joy ML

更新日期：1980-09-01 00:00:00

abstract：PURPOSE:A novel 3D printing method has been developed, which employs human CT images to construct patient specific phantoms by controlling the filament extrusion rate. METHODS:An in-house software was developed comprising pixel-by-pixel (PbP) reading of the Hounsfield Units (HU) values in the original patient DICOM im...

journal_title：Medical physics

authors： Okkalidis N

更新日期：2018-10-01 00:00:00

abstract：:It is well-known that the edge effect produced by phase contrast imaging results in the edge enhancement of x-ray images and thereby sharpens those images. It has recently been reported that phase contrast imaging using practical x-ray tubes with small focal spots has improved image sharpness as observed in the phase ...

journal_title：Medical physics

authors： Matsuo S,Katafuchi T,Tohyama K,Morishita J,Yamada K,Fujita H

更新日期：2005-08-01 00:00:00

abstract：PURPOSE:We have recently developed a dynamic tumor tracking irradiation system using Vero4DRT (MHI-Tm2 000). It is needed to create a 4D correlation model between a fiducial marker implanted near a tumor and an external surrogate as a function of time by continuously acquiring both fluoroscopy images and external surro...

journal_title：Medical physics

authors： Shiinoki T,Sawada A,Ishihara Y,Miyabe Y,Fujimoto T,Nakai T,Matsuo Y,Mizowaki T,Kokubo M,Hiraoka M

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Modulated electron radiation therapy (MERT) represents an active area of interest that offers the potential to improve healthy tissue sparing in treatment of certain cancer cases. Challenges remain however in accurate beamlet dose calculation, plan optimization, collimation method, and delivery accuracy. In thi...

journal_title：Medical physics

authors： Connell T,Alexander A,Papaconstadopoulos P,Serban M,Devic S,Seuntjens J

更新日期：2014-06-01 00:00:00

abstract：PURPOSE:Accurate deformable image registration is necessary for longitudinal studies. The error associated with commercial systems has been evaluated using computed tomography (CT). Several in-house algorithms have been evaluated for use with magnetic resonance imaging (MRI), but there is still relatively little inform...

journal_title：Medical physics

authors： Ger RB,Yang J,Ding Y,Jacobsen MC,Fuller CD,Howell RM,Li H,Jason Stafford R,Zhou S,Court LE

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:Metal artifact reduction (MAR) is a major problem and a challenging issue in x-ray computed tomography (CT) examinations. Iterative reconstruction from sinograms unaffected by metals shows promising potential in detail recovery. This reconstruction has been the subject of much research in recent years. However,...

journal_title：Medical physics

authors： Zhang H,Wang L,Li L,Cai A,Hu G,Yan B

更新日期：2016-06-01 00:00:00

abstract：PURPOSE:The aim of in vivo skin dosimetry was to measure the absorbed dose to the skin during radiotherapy, when treatment planning calculations cannot be relied on. It is of particularly importance in hypo-fractionated stereotactic modalities, where excessive dose can lead to severe skin toxicity. Currently, commercia...

journal_title：Medical physics

authors： Vicoroski N,Espinoza A,Duncan M,Oborn BM,Carolan M,Metcalfe P,Menichelli D,Perevertaylo VL,Lerch MLF,Rosenfeld AB,Petasecca M

更新日期：2017-10-01 00:00:00

abstract：:Stereotactic Body Radiation Therapy (SBRT) is being increasingly used in the radiation oncology community to treat tumors in extra-cranial sites such as spine, lung, liver, pancreas and prostate. There are well established RTOG protocols (e.g. RTOG 0631 for spine, RTOG 0813 and 0915 for lung and RTOG 0438 for liver) t...

journal_title：Medical physics

authors： Hong L

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Real-time tumor position/shape measurement and dynamic beam tracking techniques allow accurate and continuous irradiation to moving tumor, but there can be a delay of several hundred milliseconds between observation and irradiation. A time-variant seasonal autoregressive (TVSAR) model has been proposed for comp...

journal_title：Medical physics

authors： Ichiji K,Homma N,Sakai M,Narita Y,Takai Y,Yoshizawa M

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Lung cancer is a major cause of cancer deaths, and the 5-year survival rate of stage IV lung cancer patients is only 2%. However, the 5-year survival rate of stage I lung cancer patients significantly increases to 50%. As such, spiral computed tomography (CT) scans are necessary to diagnose high-risk lung cance...

journal_title：Medical physics

authors： Ma J,Zhou Z,Ren Y,Xiong J,Fu L,Wang Q,Zhao J

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:The aim of this study was to demonstrate a new model for implementing a transit dosimetry system as a means of in vivo dose verification with a water equivalent electronic portal imaging device (WE-EPID) and a conventional treatment planning system (TPS). METHOD AND MATERIALS:A standard amorphous silicon (a-Si...

journal_title：Medical physics

authors： Deshpande S,Blake SJ,Xing A,Metcalfe PE,Holloway LC,Vial P

更新日期：2018-03-01 00:00:00

abstract：:Several updated Monte Carlo (MC) codes are available to perform calculations of voxel S values for radionuclide targeted therapy. The aim of this work is to analyze the differences in the calculations obtained by different MC codes and their impact on absorbed dose evaluations performed by voxel dosimetry. Voxel S val...

journal_title：Medical physics

authors： Pacilio M,Lanconelli N,Lo MS,Betti M,Montani L,Torres AL,Coca PM

更新日期：2009-05-01 00:00:00

abstract：PURPOSE:We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale...

journal_title：Medical physics

authors： Vicente EM,Lodge MA,Rowe SP,Wahl RL,Frey EC

更新日期：2017-05-01 00:00:00

abstract：:Dose calculations for treatment planning of photon beam radiotherapy require a model of the beam to drive the dose calculation models. The beam shaping process involves scattering and filtering that yield radiation components which vary with collimator settings. The necessity to model these components has motivated th...

journal_title：Medical physics

authors： Ahnesjö A,Weber L,Murman A,Saxner M,Thorslund I,Traneus E

更新日期：2005-06-01 00:00:00

abstract：PURPOSE:Over the last ten years, there has been an extensive growth in the development of microSPECT imagers. Most of the systems are based on the combination of conventional, relatively large gamma cameras with poor intrinsic spatial resolution and multipinhole collimators working in large magnification mode. Spatial ...

journal_title：Medical physics

authors： Van Holen R,Vandeghinste B,Deprez K,Vandenberghe S

更新日期：2013-11-01 00:00:00

abstract：:The dissemination of scientific advances has changed little since the first peer-reviewed journal was published in 1665 - that is, until this past decade. The print journal, delivered by mail and stored on office shelves and in library reading rooms around the world, has been transformed by immediate, on-demand access...

journal_title：Medical physics

authors： Armato S,Hendee W,Marshall C,Curran B

更新日期：2012-06-01 00:00:00