abstract：:Statistical image reconstruction (SIR) methods have shown potential to substantially improve the image quality of low-dose x-ray computed tomography (CT) as compared to the conventional filtered back-projection (FBP) method. According to the maximum a posteriori (MAP) estimation, the SIR methods are typically formulat...

journal_title：Medical physics

authors： Zhang H,Wang J,Zeng D,Tao X,Ma J

更新日期：2018-10-01 00:00:00

abstract：PURPOSE:The Synchrony respiratory motion tracking of the CyberKnife system purports to provide real-time tumor motion compensation during robotic radiosurgery. Such a complex delivery system requires thorough quality assurance. In this work, RADPOS applicability as a dose and position quality assurance tool for CyberKn...

journal_title：Medical physics

authors： Marants R,Vandervoort E,Cygler JE

更新日期：2018-07-25 00:00:00

abstract：PURPOSE:On-board MRI can provide superb soft tissue contrast for improving liver SBRT localization. However, the availability of on-board MRI in clinics is extremely limited. On the contrary, on-board kV imaging systems are widely available on radiotherapy machines, but its capability to localize tumors in soft tissue ...

journal_title：Medical physics

authors： Harris W,Wang C,Yin FF,Cai J,Ren L

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Given its sensitivity to anatomical variations, proton therapy is expected to benefit greatly from integration with magnetic resonance imaging for online anatomy monitoring during irradiation. Such an integration raises several challenges, as both systems mutually interact. The proton beam will experience quasi...

journal_title：Medical physics

authors： Schellhammer SM,Gantz S,Lühr A,Oborn BM,Bussmann M,Hoffmann AL

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:To demonstrate the feasibility of compressed sensing (CS) to accelerate the acquisition of hyperpolarized (HP) 129 Xe multi-b diffusion MRI for quantitative assessments of lung microstructural morphometry. METHODS:Six healthy subjects and six chronic obstructive pulmonary disease (COPD) subjects underwent HP 1...

journal_title：Medical physics

authors： Zhang H,Xie J,Xiao S,Zhao X,Zhang M,Shi L,Wang K,Wu G,Sun X,Ye C,Zhou X

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Many clinical applications depend critically on the accurate differentiation and classification of different types of materials in patient anatomy. This work introduces a unified framework for accurate nonlinear material decomposition and applies it, for the first time, in the concept of triple-energy CT (TECT)...

journal_title：Medical physics

authors： Zhao W,Vernekohl D,Han F,Han B,Peng H,Yang Y,Xing L,Min JK

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiotherapy by increasing photon energy and applying specialized beam-hard...

journal_title：Medical physics

authors： Shrock Z,Yoon SW,Gunasingha R,Oldham M,Adamson J

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:Although small animal image-guided radiotherapy (SA-IGRT) systems are used increasingly in preclinical research, tools for performing routine quality assurance (QA) have not been optimized and are not readily available. Robust, efficient, and reliable QA tools are needed to ensure the accuracy and reproducibili...

journal_title：Medical physics

authors： Anvari A,Poirier Y,Sawant A

更新日期：2018-07-01 00:00:00

abstract：PURPOSE:This work describes the performance characterization of a cone-beam CT-guided radiosurgery device, the Gamma Knife® Icon™. METHODS:The performance tests have been categorized into: (a) image quality and mechanical integrity; (b) image coregistration fidelity; (c) adaptive treatment delivery quality; (d) high d...

journal_title：Medical physics

authors： Sarfehnia A,Ruschin M,Chugh B,Yeboah C,Becker N,Cho YB,Lee Y

更新日期：2018-06-29 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:Talbot-Lau x-ray interferometry provides information about the scattering and refractive properties of an object - in addition to the object's attenuation features. Until recently, this method was ineligible for imaging human-sized objects as it is challenging to adapt Talbot-Lau interferometers (TLIs) to the r...

journal_title：Medical physics

authors： Hauke C,Bartl P,Leghissa M,Ritschl L,Sutter SM,Weber T,Zeidler J,Freudenberger J,Mertelmeier T,Radicke M,Michel T,Anton G,Meinel FG,Baehr A,Auweter S,Bondesson D,Gaass T,Dinkel J,Reiser M,Hellbach K

更新日期：2018-06-01 00:00:00

abstract：PURPOSE:An optimized air ventilation system design for a treatment room in Heavy-ion Medical Facility is an important issue in the aspects of nuclear safety because the activated air produced in a treatment room can directly affect the medical staff and the general public in the radiation-free area. METHODS:Optimized ...

journal_title：Medical physics

authors： Kum O

更新日期：2018-06-01 00:00:00

abstract：PURPOSE:Using a new linear accelerator with high dose rate (800 MU/min), fast MLC motions (5.0 cm/s), fast gantry rotation (15 s/rotation), and 1 cm wide MLCs, we aimed to quantify the effects of complexity, arc number, and fractionation on interplay for breast and lung treatments under target motion. METHODS:To study...

journal_title：Medical physics

authors： Netherton T,Li Y,Nitsch P,Shaitelman S,Balter P,Gao S,Klopp A,Muruganandham M,Court L

更新日期：2018-06-01 00:00:00

abstract：PURPOSE:X-ray fluorescence computed tomography (XFCT) experiments have typically used pencil beams for data acquisition, which yielded good quality images of gold nanoparticles (AuNP) but prolonged the imaging time. Here we propose three novel collimator geometries for use with faster sheet beam XFCT data acquisition. ...

journal_title：Medical physics

authors： Dunning CAS,Bazalova-Carter M

更新日期：2018-06-01 00:00:00

abstract：PURPOSE:We describe the acceptance testing, commissioning, periodic quality assurance, and workflow procedures developed for the first clinically implemented magnetic resonance imaging-guided radiation therapy (MR-IGRT) system for real-time tracking and beam control. METHODS:The system utilizes real-time cine imaging ...

journal_title：Medical physics

authors： Green OL,Rankine LJ,Cai B,Curcuru A,Kashani R,Rodriguez V,Li HH,Parikh PJ,Robinson CG,Olsen JR,Mutic S,Goddu SM,Santanam L

更新日期：2018-05-28 00:00:00

abstract：PURPOSE:X-ray fluorescence computer tomography (XFCT) is a new molecular imaging modality which uses x-ray excitation to stimulate the emission of fluorescent photons in high atomic number contrast agents. Scatter contamination is one of the main challenges in XFCT imaging which limits the molecular sensitivity. When p...

journal_title：Medical physics

authors： Vernekohl D,Tzoumas S,Zhao W,Xing L

更新日期：2018-05-25 00:00:00

abstract：PURPOSE:To describe Acuros® CTS, a new software tool for rapidly and accurately estimating scatter in x-ray projection images by deterministically solving the linear Boltzmann transport equation (LBTE). METHODS:The LBTE describes the behavior of particles as they interact with an object across spatial, energy, and dir...

journal_title：Medical physics

authors： Maslowski A,Wang A,Sun M,Wareing T,Davis I,Star-Lack J

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:To evaluate dependence of measured dose on size and location of region of interest (ROI) in Gafchromic EBT3 film dosimetry. METHODS:Gafchromic EBT3 films were irradiated perpendicularly using the 6MV beam from a linear accelerator at 10 cm depth (100 cm SSD) of a 30 × 30 × 20 cm3 solid water phantom for a rang...

journal_title：Medical physics

authors： Gholizadeh Sendani N,Karimian A,Ferreira C,Alaei P

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:Over the last four decades, Ocular Proton Therapy has been successfully used to treat patients affected by intraocular lesions. For this, treatment geometry verification is routinely performed using radiographic images to align a configuration of fiducial radiopaque markers implanted on the sclera outer surface...

journal_title：Medical physics

authors： Via R,Hennings F,Fattori G,Fassi A,Pica A,Lomax A,Weber DC,Baroni G,Hrbacek J

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:The Small Animal Radiation Research Platform (SARRP) has been developed for conformal microirradiation with on-board cone beam CT (CBCT) guidance. The graphics processing unit (GPU)-accelerated Superposition-Convolution (SC) method for dose computation has been integrated into the treatment planning system (TPS...

journal_title：Medical physics

authors： Cho N,Tsiamas P,Velarde E,Tryggestad E,Jacques R,Berbeco R,McNutt T,Kazanzides P,Wong J

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...

journal_title：Medical physics

authors： Padilla-Cabal F,Georg D,Fuchs H

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:Different low-signal correction (LSC) methods have been shown to efficiently reduce noise streaks and noise level in CT to provide acceptable images at low-radiation dose levels. These methods usually result in CT images with highly shift-variant and anisotropic spatial resolution and noise, which makes the par...

journal_title：Medical physics

authors： Gomez-Cardona D,Hayes JW,Zhang R,Li K,Cruz-Bastida JP,Chen GH

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:Myocardial infarct (MI) may consist of an infarct core (IC) and a heterogeneous, semi-viable border zone (BZ). Patients with chronic MI in the left ventricular (LV) myocardium are at increased risk of developing ventricular arrhythmias, and may therefore qualify for implantable cardioverter defibrillator (ICD) ...

journal_title：Medical physics

authors： Farrag NA,Ramanan V,Wright GA,Ukwatta E

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Brachytherapy with 106 Ru/106 Rh plaques offers good outcomes for small-to-medium choroidal melanomas and retinoblastomas. The dose measurement of the plaques is challenging, due to the small range of the emitted beta particles and steep dose gradients involved. The scarce publications on film dosimetry of 106 ...

journal_title：Medical physics

authors： Hermida-López M,Brualla L

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Range uncertainties limit the potential of charged particle therapy. In vivo and online range verification techniques could increase the confidence in the dose delivery distribution and lead to more conformal treatments. Prompt gamma imaging and prompt gamma spectroscopy (PGS) have been demonstrated for such a ...

journal_title：Medical physics

authors： Dal Bello R,Magalhaes Martins P,Seco J

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Four-dimensional volumetric modulated arc therapy (4D VMAT) and four-dimensional intensity-modulated radiotherapy (4D IMRT) are developing radiation therapy treatment strategies designed to maximize dose conformality, minimize normal tissue dose, and deliver the treatment as efficiently as possible. The patient...

journal_title：Medical physics

authors： Klawikowski S,Tai A,Ates O,Ahunbay E,Li XA

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Patient-specific IMRT QA measurements are important components of processes designed to identify discrepancies between calculated and delivered radiation doses. Discrepancy tolerance limits are neither well defined nor consistently applied across centers. The AAPM TG-218 report provides a comprehensive review a...

journal_title：Medical physics

authors： Miften M,Olch A,Mihailidis D,Moran J,Pawlicki T,Molineu A,Li H,Wijesooriya K,Shi J,Xia P,Papanikolaou N,Low DA

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Stereotactic ablative body radiotherapy (SABR) for lung patients can be performed with volumetric-modulated arc therapy (VMAT) plans using off-axis target geometry to allow treatment in their CBCT verified position. For patient-specific quality assurance measurements using the PTW Octavius 4D phantom (PTW, Frei...

journal_title：Medical physics

authors： Jeevanandam P,Agnew CE,Irvine DM,McGarry CK

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Accurate calculation of proton stopping power ratio (SPR) relative to water is crucial to proton therapy treatment planning, since SPR affects prediction of beam range. Current standard practice derives SPR using a single CT scan. Recent studies showed that dual-energy CT (DECT) offers advantages to accurately ...

journal_title：Medical physics

authors： Shen C,Li B,Chen L,Yang M,Lou Y,Jia X

更新日期：2018-04-01 00:00:00

abstract：PURPOSE:Many biological objects, including neuronal dendrites, blood vasculature, airways, phylogenetic trees, produce tree structured data. Current methods of analysis either ignore the complex structure of trees or use distance-based methods which limit the scope of multivariate modeling. METHODS:We propose a branch...

journal_title：Medical physics

authors： Roy Choudhury K,Skwerer S

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:To assess the image quality, scatter, and leakage radiation of an integrated magnetic resonance linear accelerator (MR-LINAC or MRL) system. METHODS:A large American College of Radiology (ACR) magnetic resonance imaging (MRI) accreditation phantom was used to evaluate the MRI capabilities of the integrated MRL...

journal_title：Medical physics

authors： Wang J,Yung J,Kadbi M,Hwang K,Ding Y,Ibbott GS

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:Most modern radiotherapy machines are built with a 2D kV imaging system. Combining this imaging system with a 2D-3D inference method would allow for a ready-made option for real-time 3D tumor tracking. This work investigates and compares the accuracy of four existing 2D-3D inference methods using both motion tr...

journal_title：Medical physics

authors： Montanaro T,Nguyen DT,Keall PJ,Booth J,Caillet V,Eade T,Haddad C,Shieh CC

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:Task Group 119 (TG-119) has been adopted for evaluating the adequacy of intensity-modulated radiation therapy (IMRT) commissioning and for establishing patient-specific IMRT quality assurance (QA) passing criteria in clinical practice. TG-119 establishes 95% confidence limits (CLs), which help clinics identify ...

journal_title：Medical physics

authors： Kearney V,Solberg T,Jensen S,Cheung J,Chuang C,Valdes G

更新日期：2018-03-01 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：PURPOSE:To increase diagnostic accuracy of breast MRI by increasing temporal resolution and more accurately sampling the early kinetics of contrast media uptake. We tested the feasibility of accelerating bilateral breast DCE-MRI by reducing the FOV, allowing aliasing, and unfolding the resulting images. METHODS:Previo...

journal_title：Medical physics

authors： Pineda FD,Easley TO,Karczmar GS

更新日期：2018-03-01 00:00:00

abstract：PURPOSE:To demonstrate, via Monte Carlo simulation, that an image obtained from the patient-generated scattered radiation forced to impinge on the detector from a known direction by means of parallel-focused grids, can be used to complement the information conveyed by the primary image, such that accurate stereoscopic ...

journal_title：Medical physics

authors： Garnica-Garza HM

更新日期：2018-02-01 00:00:00

abstract：PURPOSE:To implement the DMAIC (Define-Measure-Analyze-Improve-Control) can be used for customizing the patient-specific QA by designing site-specific range tolerances. METHODS:The DMAIC framework (process flow diagram, cause and effect, Pareto chart, control chart, and capability analysis) were utilized to determine ...

journal_title：Medical physics

authors： Rah JE,Shin D,Manger RP,Kim TH,Oh DH,Kim DY,Kim GY

更新日期：2018-02-01 00:00:00

abstract：PURPOSE:Scattered radiation remains to be a major cause of image quality degradation in Flat Panel Detector (FPD)-based Cone-beam computed tomography (CBCT). We have been investigating a novel two-dimensional antiscatter grid (2D-ASG) concept to reduce scatter intensity, and hence improve CBCT image quality. We present...

journal_title：Medical physics

authors： Alexeev T,Kavanagh B,Miften M,Altunbas C

更新日期：2018-02-01 00:00:00

abstract：PURPOSE:To use EGSnrc Monte Carlo simulations for magnetic field dosimetry to determine optimal measurement orientations, calculate beam quality conversion factors for 32 cylindrical and three parallel-plate (PP) ion chambers, evaluate the beam quality and angular dependence of these factors, and examine the magnetic f...

journal_title：Medical physics

authors： Malkov VN,Rogers DWO

更新日期：2018-02-01 00:00:00

abstract：PURPOSE:Total variation minimization (TVM) is a popular and useful method for accurate CT reconstruction from few-views and limited-angle data. However, the optimization procedure of previous TVM-based algorithms is very time-consuming. The purpose of this paper was to accelerate the high image quality CT reconstructio...

journal_title：Medical physics

authors： Hou X,Teng Y,Kang Y,Qi S

更新日期：2018-02-01 00:00:00