Noise in stenosis measurement using digital subtraction angiography.

abstract：:Monte Carlo simulation dosimetry is used to compare 169Yb to 192Ir for breast high dose rate (HDR) brachytherapy applications using multiple catheter implants. Results for bare point sources show that while 169Yb delivers a greater dose rate per unit air kerma strength at the radial distance range of interest to brach...

journal_title：Medical physics

authors： Lymperopoulou G,Papagiannis P,Angelopoulos A,Karaiskos P,Georgiou E,Baltas D

更新日期：2006-12-01 00:00:00

abstract：:Frequent and repeated imaging procedures such as those performed in image-guided radiotherapy (IGRT) programs may add significant dose to radiosensitive organs of radiotherapy patients. It has been shown that kV-CBCT results in doses to bone that are up to a factor of 3-4 higher than those in surrounding soft tissue. ...

journal_title：Medical physics

authors： Ding GX,Pawlowski JM,Coffey CW

更新日期：2008-12-01 00:00:00

abstract：BACKGROUND AND PURPOSE:The purpose of this study is to develop a deep learning-based approach to simultaneously segment five pelvic organs including prostate, bladder, rectum, left and right femoral heads on cone-beam CT (CBCT), as required elements for prostate adaptive radiotherapy planning. MATERIALS AND METHODS:We...

journal_title：Medical physics

authors： Fu Y,Lei Y,Wang T,Tian S,Patel P,Jani AB,Curran WJ,Liu T,Yang X

更新日期：2020-08-01 00:00:00

abstract：PURPOSE:The application of compressed sensing (CS) technology in magnetic resonance imaging (MRI) is to accelerate the MRI scan speed by incoherent undersampling of k-space data and nonlinear iterative reconstruction of MRI images. This paper generalizes the existing rosette trajectories to configure the sampling patte...

journal_title：Medical physics

authors： Li Y,Yang R,Zhang C,Zhang J,Jia S,Zhou Z

更新日期：2015-09-01 00:00:00

abstract：:A direct data link between a CT scanner and a radiation treatment planning system has been developed. The link transmits the data serially over a coaxial cable using the pseudo-paper-tape punch and reader (serial PIO) interfaces. The data transmission rate with error-check is approximately 25,000 8-bit bytes/s. This t...

journal_title：Medical physics

authors： Abel RN,Buhler LA,Chu WT,Slater JM,Neilsen IR,Zimmerman DC

更新日期：1979-09-01 00:00:00

abstract：:Seeds containing radioactive Ytterbium-169 (169Yb) have recently been manufactured for possible application to brachytherapy. Ytterbium-169 emits photons with an average energy of 93 keV (excluding energies less than 10 keV), and decays with a half-life of 32 days. Analytic and Monte Carlo computations have been used ...

journal_title：Medical physics

authors： Mason DL,Battista JJ,Barnett RB,Porter AT

更新日期：1992-05-01 00:00:00

abstract：:A simple method to measure the line spread function of computed tomographic scanners has been developed. The line spread function of the EMI-Scanner was measured and the MTF of the scanner was calculated. The reproducibility of the method indicated this technique could be utilized to compare the spatial resolution of ...

journal_title：Medical physics

authors： Judy PF

更新日期：1976-07-01 00:00:00

abstract：PURPOSE:The authors have recently developed a cine-mode T2*/T1-weighted 4D-MRI technique and a sequential-mode T2-weighted 4D-MRI technique for imaging respiratory motion. This study aims at investigating which 4D-MRI image acquisition mode, cine or sequential, provides more accurate measurement of organ motion during ...

journal_title：Medical physics

authors： Liu Y,Yin FF,Rhee D,Cai J

更新日期：2016-01-01 00:00:00

abstract：PURPOSE:In the practice code of dosimetry, humidity effect is assumed to be constant as far as the measurements are performed in the relative humidity (RH) range of (20-80)%; thus, the humidity effect can be ignored with a dose uncertainty of 0.15%. This assumption is based on the previous experimental results by Niate...

journal_title：Medical physics

authors： Sato Y,Shimizu M,Morishita Y,Sato M,Hoshina M

更新日期：2019-09-01 00:00:00

abstract：PURPOSE:Accurate segmentation of lungs with severe interstitial lung disease (ILD) in thoracic computed tomography (CT) is an important and difficult task in the development of computer-aided diagnosis (CAD) systems. Therefore, we developed in this study a texture analysis-based method for accurate segmentation of lung...

journal_title：Medical physics

authors： Wang J,Li F,Li Q

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:To simplify the often complex and user-dependent manual region of interest (ROI) selection process for head motion monitoring, an automatic ROI selection method was developed. METHODS:The automatic ROI selection algorithm calculated the displacements and velocities of 3D surface points between a temporally cor...

journal_title：Medical physics

authors： Kang HJ,Grelewicz Z,Wiersma RD

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a novel system for patient-specific combined optimization of couch, collimator, and gantry angles for use in volumetric modulated arc therapy (VMAT) treatment planning. The system was designed to produce highly compact dose distributions by extensively sampling the 4π space. Automated fixed couch tra...

journal_title：Medical physics

authors： MacDonald RL,Syme A,Little B,Ward L,Thomas CG

更新日期：2020-02-01 00:00:00

abstract：INTRODUCTION:Ultrasound (US) guidance of the prostate has long been conducted using a transabdominal (TA) approach. More recently, a transperineal (TP) approach has been made available for image guidance. Our aim was to determine if both methods produced similar alignments within the same patients. MATERIALS AND METHO...

journal_title：Medical physics

authors： Szegedi M,Boehm C,Paxton A,Rassiah-Szegedi P,Sarkar V,Zhao H,Su F,Kokeny KE,Lloyd S,Tward J,Salter BJ

更新日期：2020-12-01 00:00:00

abstract：PURPOSE:To compare reconstructed volumes calculated via planimetry and frustum algorithms in the context of stepped transrectal ultrasound (US) imaging, and to estimate the reconstruction error for prostate volumes. METHODS:Prostate contours for 40 permanent implant patients were delineated on magnetic resonance (MR) ...

journal_title：Medical physics

authors： Liu D,Usmani N,Sloboda RS

更新日期：2013-03-01 00:00:00

abstract：:A single-field rotational total skin electron irradiation technique has recently been developed at the McGill University for treatment of skin malignancies. The dose received by a given surface point during rotation in a uniform large electron field depends on the radius of rotation of the surface point, on the local ...

journal_title：Medical physics

authors： Pla C,Heese R,Pla M,Podgorsak EB

更新日期：1984-07-01 00:00:00

abstract：PURPOSE:The ionizing radiation imparted to patients during computed tomography exams is raising concerns. This paper studies the performance of a scheme called dose reduction using prior image constrained compressed sensing (DR-PICCS). The purpose of this study is to characterize the effects of a statistical model of x...

journal_title：Medical physics

authors： Lauzier PT,Chen GH

更新日期：2013-02-01 00:00:00

abstract：PURPOSE:Stationary computed tomography (s-CT) conceptually offers several advantages over existing rotating gantry-based CT. Over the last 40 yr, s-CT has been investigated using different technological approaches. We are developing a s-CT system specifically for head/brain imaging using carbon nanotube (CNT)-based fie...

journal_title：Medical physics

authors： Spronk D,Luo Y,Inscoe CR,Lee YZ,Lu J,Zhou O

更新日期：2020-12-31 00:00:00

abstract：PURPOSE:Helical tomotherapy is a complex delivery technique, integrating CT image guidance and intensity modulated radiotherapy in a single system. The integration of the CT detector ring on the gantry not only allows patient position verification but is also often used to perform various QA procedures. This convenienc...

journal_title：Medical physics

authors： Wong JH,Hardcastle N,Tomé WA,Bayliss A,Tolakanahalli R,Lerch ML,Petasecca M,Carolan M,Metcalfe P,Rosenfeld AB

更新日期：2011-04-01 00:00:00

abstract：:Digital tomosynthesis (DTS) is a fast, low-dose three-dimensional (3D) imaging approach which yields slice images with excellent in-plane resolution, though low plane-to-plane resolution. A stack of DTS slices can be reconstructed from a single limited-angle scan, with typical scan angles ranging from 10 degrees to 40...

journal_title：Medical physics

authors： Godfrey DJ,Ren L,Yan H,Wu Q,Yoo S,Oldham M,Yin FF

更新日期：2007-08-01 00:00:00

abstract：:The purpose of this paper is to determine the correlation between dose-volume histogram (DVH) and dose wall-histogram (DWH) in the evaluation of rectal complications for prostate cancer patients treated with three-dimensional conformal radiotherapy (3D-CRT). A retrospective analysis of DVHs and DWHs of a subset of 25 ...

journal_title：Medical physics

authors： García-Vicente F,Zapatero A,Floriano A,Cruz-Conde A,Perez L,Marín A,Mínguez C,Torres JJ

更新日期：2005-08-01 00:00:00

abstract：PURPOSE:The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil ...

journal_title：Medical physics

authors： Chen CC,Chang C,Moyers MF,Gao M,Mah D

更新日期：2016-02-01 00:00:00

abstract：:A computerized scheme is being developed for the detection of masses in digital mammograms. Based on the deviation from the normal architectural symmetry of the right and left breasts, a bilateral subtraction technique is used to enhance the conspicuity of possible masses. The scheme employs two pairs of conventional ...

journal_title：Medical physics

authors： Yin FF,Giger ML,Doi K,Metz CE,Vyborny CJ,Schmidt RA

更新日期：1991-09-01 00:00:00

abstract：:A water beam imaging system (WBIS) has been developed and used to verify dose distributions for intensity modulated radiotherapy using dynamic multileaf collimator. This system consisted of a water container, a scintillator screen, a charge-coupled device camera, and a portable personal computer. The scintillation ima...

journal_title：Medical physics

authors： Li JS,Boyer AL,Ma CM

更新日期：2001-12-01 00:00:00

abstract：:The wall of an ionization chamber is commonly assumed to have a negligible effect on chamber response in electron beams. For cylindrical chambers with thin walls this assumption is valid. However, parallel-plate chambers commonly possess large mechanical supports which may affect chamber response in a manner not accou...

journal_title：Medical physics

authors： Hunt MA,Kutcher GJ,Buffa A

更新日期：1988-01-01 00:00:00

abstract：PURPOSE:To formulate convex planning objectives of treatment plan multicriteria optimization with explicit relationships to the dose-volume histogram (DVH) statistics used in plan quality evaluation. METHODS:Conventional planning objectives are designed to minimize the violation of DVH statistics thresholds using pena...

journal_title：Medical physics

authors： Engberg L,Forsgren A,Eriksson K,Hårdemark B

更新日期：2017-06-01 00:00:00

abstract：:Depending on the clinical application, it is frequently necessary to tilt the gantry of an x-ray CT system with respect to the patient and couch. For single-slice fan-beam systems, tilting the gantry introduces no errors or artifacts. Most current systems, however, are helical multislice systems with up to 16 slices. ...

journal_title：Medical physics

authors： Hein I,Taguchi K,Silver MD,Kazama M,Mori I

更新日期：2003-12-01 00:00:00

abstract：PURPOSE:To use machine-learning algorithms and blur measure (BM) operators to automatically detect motion blur in mammograms. Motion blur has been reported to reduce lesion detection performance and mask small abnormalities, resulting in failure to detect them until they reach more advanced stages. Automatic detection ...

journal_title：Medical physics

authors： Kamona N,Loew M

更新日期：2020-04-01 00:00:00

abstract：PURPOSE:In breast radiotherapy with intensity modulation, it is a well established practice to extend the dose fluence outside the limit of the body contour to account for small changes in size and position of the target and the rest of the tissues due to respiration or to possible oedema. A simple approach is not appl...

journal_title：Medical physics

authors： Giorgia N,Antonella F,Alessandro C,Eugenio V,Luca C

更新日期：2011-07-01 00:00:00

abstract：:Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray ...

journal_title：Medical physics

authors： Carelsen B,Bakker NH,Strackee SD,Boon SN,Maas M,Sabczynski J,Grimbergen CA,Streekstra GJ

更新日期：2005-09-01 00:00:00

abstract：PURPOSE:By means of Monte Carlo (MC) simulations and indirect measurements, we have evaluated the maximum dose rates achievable with conventional x-ray tubes and related them to FLASH therapy dose rates of >40 Gy/s. METHODS:Monte Carlo models of two 160 kV x-ray tubes, the 3-kW MXR-160/22 and the 6-kW MXR-165, were bu...

journal_title：Medical physics

authors： Bazalova-Carter M,Esplen N

更新日期：2019-12-01 00:00:00