SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) for low dose x-ray imaging: spatial resolution.

abstract：:The purpose of the present study is to characterize electron contamination in photon beams in different clinical situations. Variations with field size, beam modifier (tray, shaping block) and source-surface distance (SSD) were studied. Percentage depth dose measurements with and without a purging magnet and replacing...

journal_title：Medical physics

authors： Lopez Medina A,Teijeiro A,Garcia J,Esperon J,Terron JA,Ruiz DP,Carrion MC

更新日期：2005-05-01 00:00:00

abstract：:Volumetric modulated arc therapy (VMAT) has recently been used to improve the dose distribution and efficiency of treatment delivery over the standard intensity-modulated radiotherapy (IMRT) technique. This study compares the dosimetry between RapidArc plan and standard IMRT plan for head and neck cancer. Three head a...

journal_title：Medical physics

authors： Jiang R,Fleck A,Schaly B,Charland P,Zhan L,Alliet K,Rachakonda R,Osei E

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:High-Z material in computed tomography (CT) yields metal artifacts that degrade image quality and may cause substantial errors in dose calculation. This study couples a metal artifact reduction (MAR) algorithm with enhanced 16-bit depth (vs standard 12-bit) to quantify potential gains in image quality and dosim...

journal_title：Medical physics

authors： Glide-Hurst C,Chen D,Zhong H,Chetty IJ

更新日期：2013-06-01 00:00:00

abstract：:The concept of equivalent uniform dose (EUD) has been suggested as a means to quantitatively consider heterogeneous dose distributions within targets. Tumor cell density/function is typically assumed to be uniform. We herein propose to use 18F-labeled 2-deoxyglucose (FDG) positron emission tomography (PET) tumor imagi...

journal_title：Medical physics

authors： Zhou SM,Wong TZ,Marks LB

更新日期：2004-09-01 00:00:00

abstract：PURPOSE:Several treatment response metrics, such as RECIST and PERCIST, have been established for assessing individual solid tumors. However, metastatic prostate cancer poses a unique challenge to these metrics because bone lesions are often numerous and non-measureable. This study investigated the impact of using diff...

journal_title：Medical physics

authors： Morrison C,Liu G,Jeraj R

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To study and compare the dose response curves of the new GafChromic EBT3 film for megavoltage and kilovoltage x-ray beams, with different spatial resolution. METHODS:Two sets of EBT3 films (lot#A101711-02) were exposed to each x-ray beam (6MV, 15MV and 50kV) at 8 dose values (50-3200cGy). The megavoltage beams...

journal_title：Medical physics

authors： Chiu-Tsao S,Massillon-Jl G,Domingo-Muñoz I,Chan M

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:One of the promising options for motion management in radiation therapy (RT) is the use of LINAC-compatible robotic-arm-mounted ultrasound imaging system due to its high soft tissue contrast, real-time capability, absence of ionizing radiation, and low cost. The purpose of this work is to develop a novel deep l...

journal_title：Medical physics

authors： Huang P,Yu G,Lu H,Liu D,Xing L,Yin Y,Kovalchuk N,Xing L,Li D

更新日期：2019-05-01 00:00:00

abstract：PURPOSE:It is important to enhance image quality for low-dose CT acquisitions to push the ALARA boundary. Current state-of-the-art block-matching three-dimensional (BM3D) denoising scheme assumes white Gaussian noise (WGN) model. This study proposes a novel filtering module to be incorporated into the BM3D framework fo...

journal_title：Medical physics

authors： Zhao T,Hoffman J,McNitt-Gray M,Ruan D

更新日期：2019-01-01 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：:Recent absorbed-dose-based protocols allow for two methods of calibrating electron beams using plane-parallel chambers, one using the N(Co)D,w for a plane-parallel chamber, and the other relying on cross-calibration of the plane-parallel chamber in a high-energy electron beam against a cylindrical chamber which has an...

journal_title：Medical physics

authors： Stewart KJ,Seuntjens JP

更新日期：2002-03-01 00:00:00

abstract：PURPOSE:For the purpose of size-specific dose estimation, information regarding patient attenuation is required. The purpose of this work is to describe a method for measuring patient attenuation and expressing the results in terms of a water cylinder, with cross sectional area A(w), which would absorb the same average...

journal_title：Medical physics

authors： Wang J,Duan X,Christner JA,Leng S,Yu L,McCollough CH

更新日期：2012-11-01 00:00:00

abstract：:Intensity modulated radiation therapy (IMRT) with a dynamic multileaf collimator (DMLC) requires synchronization of DMLC leaf motion with dose delivery. A delay in DMLC communication is known to cause leaf lag and lead to dosimetric errors. The errors may be exacerbated by gated operation. The purpose of this study wa...

journal_title：Medical physics

authors： Duan J,Shen S,Fiveash JB,Brezovich IA,Popple RA,Pareek PN

更新日期：2003-08-01 00:00:00

abstract：PURPOSE:Volumetric x-ray microcomputed tomography (CT) can be employed in a variety of quantitative research applications such as image-guided interventions or characterization of medical devices. To ensure the highest geometric fidelity of images for these applications, a phantom and image processing algorithm have be...

journal_title：Medical physics

authors： Waring CS,Bax JS,Samarabandu A,Holdsworth DW,Fenster A,Lacefield JC

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:To evaluate the treatment planning system (TPS) performance of the ZAP-X stereotactic radiosurgery (SRS) system through nondosimetric, dosimetric, and end-to-end (E2E) tests. METHODS:A comprehensive set of TPS commissioning and validation tests were developed using published guidelines. Nondosimetric validatio...

journal_title：Medical physics

authors： Srivastava SP,Jani SS,Pinnaduwage DS,Yan X,Rogers L,Barranco FD,Barani IJ,Sorensen S

更新日期：2021-01-28 00:00:00

abstract：PURPOSE:This paper describes the low-kV spectral optimization of dual-energy CT (DECT) equipped with high-kV tin filtration for the quantitative acquisition of electron density information, which is essential for treatment planning in radiotherapy. In addition, an analytical DECT image simulation was preliminarily perf...

journal_title：Medical physics

authors： Saito M

更新日期：2011-06-01 00:00:00

abstract：PURPOSE:The authors investigated the performance of a recently introduced 160-mm/256-row CT system for low dose quantitative myocardial perfusion (MP) imaging of the whole heart. This platform is equipped with a gantry capable of rotating at 280 ms per full cycle, a second generation of adaptive statistical iterative r...

journal_title：Medical physics

authors： So A,Imai Y,Nett B,Jackson J,Nett L,Hsieh J,Wisenberg G,Teefy P,Yadegari A,Islam A,Lee TY

更新日期：2016-08-01 00:00:00

abstract：PURPOSE:The Acuros XB (AXB) Advanced Dose algorithm (Varian Medical Systems) represents a dramatic shift in clinical photon dose calculation methodology from pencil-beam superposition/convolution methods. Early studies evaluating the accuracy of the algorithm in lung have found good agreement with both measurement and ...

journal_title：Medical physics

authors： Bush K,Wang L,Mok E

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The authors discuss measurement methods and instrumentation useful for the characterization of the gray tracking performance of medical color monitors for diagnostic applications. The authors define gray tracking as the variability in the chromaticity of the gray levels in a color monitor. METHODS:The authors ...

journal_title：Medical physics

authors： Badano A,Wang J,Boynton P,Le Callet P,Cheng WC,Deroo D,Flynn MJ,Matsui T,Penczek J,Revie C,Samei E,Steven PM,Swiderski S,Van Hoey G,Yamaguchi M,Hasegawa M,Nagy BV

更新日期：2016-07-01 00:00:00

abstract：PURPOSE:Target localization accuracy of cone-beam CT (CBCT) images used in radiation treatment of respiratory disease sites is affected by motion artifacts (blurring and streaking). The authors have previously reported on a method of respiratory motion correction in thoracic CBCT at end expiration (EE). The previous re...

journal_title：Medical physics

authors： Dzyubak O,Kincaid R,Hertanto A,Hu YC,Pham H,Rimner A,Yorke E,Zhang Q,Mageras GS

更新日期：2014-10-01 00:00:00

abstract：:Vessel size measurement is perhaps the most often performed quantitative analysis in diagnostic and interventional angiography. Although automated vessel sizing techniques are generally considered to have good accuracy and precision, we have observed that clinicians rarely use these techniques in standard clinical pra...

journal_title：Medical physics

authors： Hoffmann KR,Dmochowski J,Nazareth DP,Miskolczi L,Nemes B,Gopal A,Wang Z,Rudin S,Bednarek DR

更新日期：2003-04-01 00:00:00

abstract：PURPOSE:To compare and evaluate intensity-based registration methods for computation of serial x-ray mammogram correspondence. METHODS:X-ray mammograms were simulated from MRIs of 20 women using finite element methods for modeling breast compressions and employing a MRI/x-ray appearance change model. The parameter con...

journal_title：Medical physics

authors： Pinto Pereira SM,Hipwell JH,McCormack VA,Tanner C,Moss SM,Wilkinson LS,Khoo LA,Pagliari C,Skippage PL,Kliger CJ,Hawkes DJ,Silva IM

更新日期：2010-09-01 00:00:00

abstract：:The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Rese...

journal_title：Medical physics

authors： McCaffrey JP,Shen H,Downton B,Mainegra-Hing E

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:In this abstract, we discuss a biomechanical head and neck model that will be able to represent patient setup variations as well as physiologic changes and subsequently enable dose calculations on the deformed anatomy. METHODS:We selected Multi Pose MRI as the imaging modality to aid in model development and v...

journal_title：Medical physics

authors： Santhanam A,Ennis D,Low D,Kupelian P

更新日期：2012-06-01 00:00:00

abstract：:The large variation of x-ray fluence at the detector in cone-beam CT (CBCT) poses a significant challenge to detectors' limited dynamic range, resulting in the loss of skinline as well as reduction of CT number accuracy, contrast-to-noise ratio, and image uniformity. The authors investigate the performance of a bowtie...

journal_title：Medical physics

authors： Mail N,Moseley DJ,Siewerdsen JH,Jaffray DA

更新日期：2009-01-01 00:00:00

abstract：:Our purpose in this work was to assess the reliability of the calibration coefficient for magnetic resonance water proton chemical shift temperature mapping. Over a six month period, the calibration coefficient was measured 15 times in several different phantoms. A highly linear relationship between water proton chemi...

journal_title：Medical physics

authors： Wu T,Kendell KR,Felmlee JP,Lewis BD,Ehman RL

更新日期：2000-01-01 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 determine the accuracy and reproducibility of the automatic- setup procedure of a 3D water scanner (3D SCANNER, Sun Nuclear Corp). The procedure automatically aligns the scanner's coordinate system to the Linac coordinate system. A unique off-center detector holder extends the scan range to 630 mm, eliminati...

journal_title：Medical physics

authors： Li J,Lu B,Yan G,Huang Y,Liu C

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a novel three-dimensional (3D) hybrid-encoding framework using compressed sensing (CS) and Toeplitz encoding with variable phase-scrambled radio-frequency (RF) excitation, which has the following advantages: low power deposition of RF pulses, reduction of the signal dynamic range, no additional hardw...

journal_title：Medical physics

authors： Wang H,Liang D,Su S,King KF,Chang Y,Liu X,Zheng H,Ying L

更新日期：2020-04-01 00:00:00

abstract：PURPOSE:High-spatial-resolution x-ray imaging in the few-ten-keV range is becoming increasingly important in several applications, such as small-animal imaging and phase-contrast imaging. The detector properties critically influence the quality of such imaging. Here the authors present a quantitative comparison of scin...

journal_title：Medical physics

authors： Larsson JC,Lundström U,Hertz HM

更新日期：2016-06-01 00:00:00

abstract：:In this article, we report on the development of a simple and accurate method for quality assurance of electron beam output and energy. Aluminum disks of thicknesses d(max) or d50 of the particular electron energy are positioned sequentially over a parallel-plate ion chamber and the ratio of the two signals is compare...

journal_title：Medical physics

authors： Woo MK,Videla NG

更新日期：2004-05-01 00:00:00