Noise, resolution, and sensitivity considerations in the design of a single-slice emission-transmission computed tomographic system.

abstract：PURPOSE:This article aims to introduce a novel algorithm for fast beam angle selection in intensity modulated radiotherapy (IMRT). METHODS:The algorithm models the optimization problem as a beam angle ranking problem and chooses suitable beam angles according to their rank. A new parameter called "beam intensity profi...

journal_title：Medical physics

authors： Vaitheeswaran R,Narayanan VK,Bhangle JR,Nirhali A,Kumar N,Basu S,Maiya V

更新日期：2010-12-01 00:00:00

abstract：PURPOSE/OBJECTIVE:Couch and MLC tracking are two novel techniques to mitigate intrafractional tumor motion on a conventional linear accelerator, but both techniques still have residual dosimetric errors. Here, we first propose and experimentally validate a software tool to simulate couch and MLC tracking, and then use ...

journal_title：Medical physics

authors： Toftegaard J,Hansen R,Ravkilde T,Macek K,Poulsen PR

更新日期：2017-03-01 00:00:00

abstract：:Empirical functions that describe primary beam profiles for radiotherapy treatment planning systems generally account for finite source size only on beams unmodified by blocks, wedges, or compensating filters. To incorporate the effects of extended sources on such modified beams and to treat the effect of an extended ...

journal_title：Medical physics

authors： Starkschall G

更新日期：1988-09-01 00:00:00

abstract：:Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal p...

journal_title：Medical physics

authors： Tward DJ,Siewerdsen JH,Daly MJ,Richard S,Moseley DJ,Jaffray DA,Paul NS

更新日期：2007-11-01 00:00:00

abstract：:To more accurately and precisely delineate a tumor in a 3D PET image, we proposed a novel, semi-automatic, two-stage method by utilizing an adaptive region-growing algorithm and a dual-front active contour model. First, a rough region of interest (ROI) is manually drawn by a radiation oncologist that encloses a tumor....

journal_title：Medical physics

authors： Li H,Thorstad WL,Biehl KJ,Laforest R,Su Y,Shoghi KI,Donnelly ED,Low DA,Lu W

更新日期：2008-08-01 00:00:00

abstract：:Stereo x-ray radiography attracts increasing attention in major clinical applications. The purpose of this paper is to analyze the 3D localization error for breast biopsy procedures and provide guidelines for improving its accuracy. Our prototype is a CCD based digital stereo x-ray imaging system. The mathematical mod...

journal_title：Medical physics

authors： Jiang H,Liu H,Wang G,Chen W,Fajardo LL

更新日期：2000-05-01 00:00:00

abstract：:Lag in fluoroscopic systems introduces a frame-averaging effect that reduces measurements of image noise and incorrectly inflates measurements of the detective quantum efficiency (DQE). A correction can be implemented based on measurements of the temporal modulation transfer function (MTF). We introduce a method of me...

journal_title：Medical physics

authors： Friedman SN,Cunningham IA

更新日期：2008-06-01 00:00:00

abstract：PURPOSE:The purpose of this study is to quantify the change in monthly VMAT quality assurance (QA) and determine the tests to maintain consistent delivery with a baseline. METHODS:VMAT monthly QA has been performed for over 14 months on two Elekta Synergy LINACs. A baseline was established at acceptance and the monthl...

journal_title：Medical physics

authors： Stenbeck J,Oves S,Gebreamlak W,Alkhatib H

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a method of (a) calculating the dose rate of voxels within a proton field delivered using pencil beam scanning (PBS), and (b) reporting a representative dose rate for the PBS treatment field that enables correspondence between multiple treatment modalities. This method takes into account the unique s...

journal_title：Medical physics

authors： Folkerts MM,Abel E,Busold S,Perez JR,Krishnamurthi V,Ling CC

更新日期：2020-12-01 00:00:00

abstract：:We describe a unique method that allows the comparison of spatially registered ultrasound (SRUS) images and computed tomography-derived contours (CTDCs) that were acquired with a minimal time lapse. As such, we have a tool that will provide validation of the spatial accuracy of the US system and that will allow compar...

journal_title：Medical physics

authors： Molloy JA,Srivastava S,Schneider BF

更新日期：2004-03-01 00:00:00

abstract：PURPOSE:Radiotherapy, especially with charged particles, is sensitive to executional and preparational uncertainties that propagate to uncertainty in dose and plan quality indicators, for example, dose-volume histograms (DVHs). Current approaches to quantify and mitigate such uncertainties rely on explicitly computed e...

journal_title：Medical physics

authors： Wahl N,Hennig P,Wieser HP,Bangert M

更新日期：2020-10-01 00:00:00

abstract：PURPOSE:Motion is a major confound of image quality in MRI. A method of retrospectively correcting the effects of rotations and translations on the acquired k-space data is presented. METHODS:In two phantom experiments of well-controlled translation and rotation, two MRI-compatible infrared cameras recorded motion dat...

journal_title：Medical physics

authors： Marxen M,Marmurek J,Baker N,Graham SJ

更新日期：2009-12-01 00:00:00

abstract：:Breast density is a strong predictor of the failure of mammography screening to detect breast cancer and is a strong predictor of the risk of developing breast cancer. The many imaging options that are now available for imaging dense breasts show great promise, but there is still the question of determining which wome...

journal_title：Medical physics

authors： Ng KH,Lau S

更新日期：2015-12-01 00:00:00

abstract：:We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD...

journal_title：Medical physics

authors： Goodsitt MM,Chan HP,Lydick JT,Gandra CR,Chen NG,Helvie MA,Bailey JE,Roubidoux MA,Paramagul C,Blane CE,Sahiner B,Petrick NA

更新日期：2004-06-01 00:00:00

abstract：:Part III (oral exam) is the final part of ABR board exam for Diagnostic Medical Physics. In this exam, each of five oral examiners questions the candidate in each of five question categories. Oral exam has unique challenges to the candidate compared with the written exams. The candidate is expected to have not only ad...

journal_title：Medical physics

authors： Leng S,Chen L,Shu Y,McCollough C

更新日期：2012-06-01 00:00:00

abstract：:Fluoroscopy is a low dose imaging technique. As such, a very sensitive detector is required to create images of good quality. Present day flat panel active matrix read out systems introduce an amount of noise that inhibits present direct and indirect methods from producing optimal quality images at fluoroscopic exposu...

journal_title：Medical physics

authors： Hunt DC,Kirby SS,Rowlands JA

更新日期：2002-11-01 00:00:00

abstract：PURPOSE:To develop a new scintillating fiber-based electronic portal imaging device (EPID) with a high quantum efficiency (QE) while preserving an adequate spatial resolution. METHODS:Two prototypes were built: one with a single pixel readout and the other with an active matrix flat-panel imager (AMFPI) for readout. T...

journal_title：Medical physics

authors： Liu J,Xu Y,Teymurazyan A,Papandreou Z,Pang G

更新日期：2020-01-01 00:00:00

abstract：PURPOSE:High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To ...

journal_title：Medical physics

authors： Guthier CV,Devlin PM,Harris TC,O'Farrell DA,Cormack RA,Buzurovic I

更新日期：2020-03-01 00:00:00

abstract：:An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are ...

journal_title：Medical physics

authors： Rice JR,Milbrandt RH,Madsen EL,Frank GR,Boote EJ,Blechinger JC

更新日期：1998-07-01 00:00:00

abstract：:This paper is concerned with the proposed Birmingham accelerator-based epithermal neutron beam for boron neutron capture therapy (BNCT). In particular, the option of producing a therapy beam at an orthogonal direction to the incoming protons is considered. Monte Carlo radiation transport simulations, both with and wit...

journal_title：Medical physics

authors： Allen DA,Beynon TD,Green S

更新日期：1999-01-01 00:00:00

abstract：PURPOSE:Tomosynthesis is a promising modality for breast imaging. The appearance of the tomosynthesis reconstructed image is greatly affected by the choice of acquisition and reconstruction parameters. The purpose of this study was to investigate the limitations of tomosynthesis breast imaging due to scan parameters an...

journal_title：Medical physics

authors： Reiser I,Nishikawa RM

更新日期：2010-04-01 00:00:00

abstract：:Transmission data for 4-MV bremsstrahlung beams have been measured with a combination of lead and aluminum attenuators. From these data, the original energy spectra have been reconstructed using an iterative least-squares technique, previously evaluated by simulation studies. The spectra on the central axis for three ...

journal_title：Medical physics

authors： Huang PH,Kase KR,Bjärngard BE

更新日期：1983-11-01 00:00:00

abstract：:Age-related macular degeneration (AMD) is a leading cause for vision loss for people over the age of 65 in the United States and a major health problem worldwide. Research for new treatments of the wet form of the disease using kilovoltage stereotactic radiosurgery is currently underway at Oraya Therapeutics, Inc. In ...

journal_title：Medical physics

authors： Hanlon J,Lee C,Chell E,Gertner M,Hansen S,Howell RW,Bolch WE

更新日期：2009-08-01 00:00:00

abstract：:Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for...

journal_title：Medical physics

authors： Hardcastle N,Soisson E,Metcalfe P,Rosenfeld AB,Tome WA

更新日期：2008-11-01 00:00:00

abstract：PURPOSE:Mammographic density of glandular breast tissue has a masking effect that can reduce lesion detection accuracy and is also a strong risk factor for breast cancer. Therefore, accurate quantitative estimation of breast density is clinically important. In this study, we investigate experimentally the feasibility o...

journal_title：Medical physics

authors： Ghammraoui B,Badal A,Glick SJ

更新日期：2018-06-03 00:00:00

abstract：PURPOSE:The paper presents a complete computer-aided detection (CAD) system for the detection of lung nodules in computed tomography images. A new mixed feature selection and classification methodology is applied for the first time on a difficult medical image analysis problem. METHODS:The CAD system was trained and t...

journal_title：Medical physics

authors： Tan M,Deklerck R,Jansen B,Bister M,Cornelis J

更新日期：2011-10-01 00:00:00

abstract：PURPOSE:Patient motion is a common problem during dynamic positron emission tomography (PET) scans for quantification of myocardial blood flow (MBF). The purpose of this study was to quantify the prevalence of body motion in a clinical setting and evaluate with realistic phantoms the effects of motion on blood flow qua...

journal_title：Medical physics

authors： Hunter CR,Klein R,Beanlands RS,deKemp RA

更新日期：2016-04-01 00:00:00

abstract：:Projected light fields are used on treatment simulators and teletherapy treatment units to delineate the size and position of the radiation beam. Any discrepancy between these fields will lead to a systematic field placement error, with possibly serious implications with regard to the accuracy of the delivered dose di...

journal_title：Medical physics

authors： Luchka K,Chen D,Shalev S,Gluhchev G,Rajapakshe R

更新日期：1996-07-01 00:00:00

abstract：:The feasibility of using film dosimetry data as the input data for patient treatment planning was evaluated. The central-axis depth dose and the off-axis ratios obtained from film measurements in a solid phantom were compared with those of ion-chamber measurements in water. Two techniques were used to generate isodose...

journal_title：Medical physics

authors： Shiu AS,Otte VA,Hogstrom KR

更新日期：1989-11-01 00:00:00

abstract：:Registration of single slices from FluoroCT, CineMR, or interventional magnetic resonance imaging to three dimensional (3D) volumes is a special aspect of the two-dimensional (2D)/3D registration problem. Rather than digitally rendered radiographs (DRR), single 2D slice images obtained during interventional procedures...

journal_title：Medical physics

authors： Birkfellner W,Figl M,Kettenbach J,Hummel J,Homolka P,Schernthaner R,Nau T,Bergmann H

更新日期：2007-01-01 00:00:00