abstract：PURPOSE:To assess and compare the dosimetric impact of dynamic multileaf collimator (DMLC) tracking and gating as motion correction strategies to account for intrafraction motion during conventionally fractionated prostate radiotherapy. METHODS:A dose reconstruction method was used to retrospectively assess the dose d...

journal_title：Medical physics

authors： Colvill E,Poulsen PR,Booth JT,O'Brien RT,Ng JA,Keall PJ

更新日期：2014-09-01 00:00:00

abstract：PURPOSE:Treatments like radiotherapy and focused ultrasound in the abdomen require accurate motion tracking, in order to optimize dosage delivery to the target and minimize damage to critical structures and healthy tissues around the target. 4D ultrasound is a promising modality for motion tracking during such treatmen...

journal_title：Medical physics

authors： Vijayan S,Klein S,Hofstad EF,Lindseth F,Ystgaard B,Langø T

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:Hybrid radiotherapy-MRI devices promise real time tracking of moving tumors to focus the radiation portals to the tumor during irradiation. This approach will benefit from the increased temporal resolution of MRI's data acquisition and reconstruction. In this work, the authors propose a novel spatial-temporal c...

journal_title：Medical physics

authors： Yip E,Yun J,Wachowicz K,Heikal AA,Gabos Z,Rathee S,Fallone BG

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:With increased use of handheld and tablet display devices for viewing medical images, methods for consistently measuring reflectivity of the devices are needed. In this note, the authors report on the characterization of diffuse reflections for handheld display devices including mobile phones and tablets using ...

journal_title：Medical physics

authors： Liu P,Badano A

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:To evaluate the accuracy of skin dose determination for composite multibeam 3D conformal radiation therapy (3DCRT) and intensity modulated radiation therapy (IMRT) treatments using optically stimulated luminescent dosimeters (OSLDs) and Eclipse treatment planning system. METHODS:Surface doses measured by OSLDs...

journal_title：Medical physics

authors： Zhuang AH,Olch AJ

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:The aim of this study was to evaluate the suitability of several detectors for the determination of absorbed dose in bone. METHODS:Three types of ultrathin LiF-based thermoluminescent dosimeters (TLDs)-two LiF:Mg,Cu,P-based (MCP-Ns and TLD-2000F) and a (7)Li-enriched LiF:Mg,Ti-based (MTS-7s)-as well as EBT2 Ga...

journal_title：Medical physics

authors： Bueno M,Carrasco P,Jornet N,Muñoz-Montplet C,Duch MA

更新日期：2014-08-01 00:00:00

abstract：PURPOSE:To measure patient-specific maximum skin dose (MSD) associated with CT fluoroscopy (CTF) lung biopsies and to compare measured MSD with the MSD estimated from phantom measurements, as well as with the CTDIvol of patient examinations. METHODS:Data from 50 patients with lung lesions who underwent a CT fluoroscop...

journal_title：Medical physics

authors： Zanca F,Jacobs A,Crijns W,De Wever W

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:An original radionuclide calibrator method for activity determination is presented. The method could be used for intercomparison surveys for short half-life radioactive sources used in Nuclear Medicine, such as(99m)Tc or most positron emission tomography radiopharmaceuticals. METHODS:By evaluation of the resul...

journal_title：Medical physics

authors： Oliveira PA,Santos JA

更新日期：2014-07-01 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:Efficacy of tuberculosis (TB) treatment is often monitored using chest radiography. Monitoring size of cavities in pulmonary tuberculosis is important as the size predicts severity of the disease and its persistence under therapy predicts relapse. The authors present a method for automatic cavity segmentation i...

journal_title：Medical physics

authors： Maduskar P,Hogeweg L,de Jong PA,Peters-Bax L,Dawson R,Ayles H,Sánchez CI,van Ginneken B

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:Cone beam computed tomography (CBCT) image quality suffers from contamination from scattered photons in the projection images. Monte Carlo simulations are a powerful tool to investigate the properties of scattered photons.egs_cbct, a recent EGSnrc user code, provides the ability of performing fast scatter calcu...

journal_title：Medical physics

authors： Thing RS,Mainegra-Hing E

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:For accurate tissue inhomogeneity correction in radiotherapy treatment planning, the authors had previously proposed a novel conversion of the energy-subtracted CT number to an electron density (ΔHU-ρe conversion), which provides a single linear relationship between ΔHU and ρe over a wide ρe range. The purpose ...

journal_title：Medical physics

authors： Saito M,Tsukihara M

更新日期：2014-07-01 00:00:00

abstract：PURPOSE:The objectives are: (i) assess the development of the impedance of some arteries during the first decades of life; (ii) determine the influence of pulse rate in arterial impedance; (iii) compare the structure of some arterial segments with optimized structures with respect to blood flow; and (iv) explain the el...

journal_title：Medical physics

authors： Silva C,Reis AH

更新日期：2014-06-01 00:00:00

abstract：PURPOSE:Results about the feasibility of a method for quasi real time in vivo dosimetry (IVD) at the isocenter point for volumetric modulated arc therapy (VMAT) are here reported. The method is based on correlations between the EPID signal and the dose on the beam central axis. Moreover, the γ-analysis of EPID images w...

journal_title：Medical physics

authors： Fidanzio A,Porcelli A,Azario L,Greco F,Cilla S,Grusio M,Balducci M,Valentini V,Piermattei A

更新日期：2014-06-01 00:00:00

abstract：PURPOSE:To investigate the effect of the number of projection views on image noise in cone-beam CT (CBCT) with a flat-panel detector. METHODS:This fairly fundamental consideration in CBCT system design and operation was addressed experimentally (using a phantom presenting a uniform medium as well as statistically moti...

journal_title：Medical physics

authors： Zhao Z,Gang GJ,Siewerdsen JH

更新日期：2014-06-01 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:Adequate evaluation of the results from multi-institutional trials involving light ion beam treatments requires consideration of the planning margins applied to both targets and organs at risk. A major uncertainty that affects the size of these margins is the conversion of x ray computed tomography numbers (XCT...

journal_title：Medical physics

authors： Moyers MF

更新日期：2014-06-01 00:00:00

abstract：PURPOSE:Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measure...

journal_title：Medical physics

authors： Kotasidis FA,Angelis GI,Anton-Rodriguez J,Matthews JC,Reader AJ,Zaidi H

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:The absolute dose rate of the Imaging and Medical Beamline (IMBL) on the Australian Synchrotron was measured with a graphite calorimeter. The calorimetry results were compared to measurements from the existing free-air chamber, to provide a robust determination of the absolute dose in the synchrotron beam and p...

journal_title：Medical physics

authors： Harty PD,Lye JE,Ramanathan G,Butler DJ,Hall CJ,Stevenson AW,Johnston PN

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:To evaluate a three-equation three-unknown dual-energy quantitative CT (DEQCT) technique for determining region specific variations in bone spongiosa composition for improved red marrow dose estimation in radionuclide therapy. METHODS:The DEQCT method was applied to 80/140 kVp images of patient-simulating lumb...

journal_title：Medical physics

authors： Goodsitt MM,Shenoy A,Shen J,Howard D,Schipper MJ,Wilderman S,Christodoulou E,Chun SY,Dewaraja YK

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:The purpose of the study is to investigate the characteristics of a two-dimensional (2D) liquid-filled ion chamber detector array, which is used for the verification of radiotherapy treatment plans that use small field sizes of up to 10 × 10 cm. METHODS:The device used in this study was Octavius 1000 SRS model...

journal_title：Medical physics

authors： Markovic M,Stathakis S,Mavroidis P,Jurkovic IA,Papanikolaou N

更新日期：2014-05-01 00:00:00

abstract：PURPOSE:Cone-beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate three-dimensional (3D) models for the diagnosis and treatmen...

journal_title：Medical physics

authors： Wang L,Chen KC,Gao Y,Shi F,Liao S,Li G,Shen SG,Yan J,Lee PK,Chow B,Liu NX,Xia JJ,Shen D

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:Effective dose (ED) is a widely used metric for comparing ionizing radiation burden between different imaging modalities, scanners, and scan protocols. In computed tomography (CT), ED can be estimated by performing scans on an anthropomorphic phantom in which metal-oxide-semiconductor field-effect transistor (M...

journal_title：Medical physics

authors： Trattner S,Cheng B,Pieniazek RL,Hoffmann U,Douglas PS,Einstein AJ

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:To improve the efficiency of atlas-based segmentation without compromising accuracy, and to demonstrate the validity of the proposed method on MRI-based prostate segmentation application. METHODS:Accurate and efficient automatic structure segmentation is an important task in medical image processing. Atlas-bas...

journal_title：Medical physics

authors： Xie Q,Ruan D

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:To provide specific experience-based guidance and recommendations for centers wishing to develop, validate, and implement an accurate and efficient process for directly using positron emission tomography-computed tomography (PET-CT) for the radiotherapy planning of head and neck cancer patients. METHODS:A PET-...

journal_title：Medical physics

authors： Thomas CM,Pike LC,Hartill CE,Baker S,Woods E,Convery DJ,Greener AG

更新日期：2014-04-01 00:00:00

abstract：:An addendum to the AAPM's TG-51 protocol for the determination of absorbed dose to water in megavoltage photon beams is presented. This addendum continues the procedure laid out in TG-51 but new kQ data for photon beams, based on Monte Carlo simulations, are presented and recommendations are given to improve the accur...

journal_title：Medical physics

authors： McEwen M,DeWerd L,Ibbott G,Followill D,Rogers DW,Seltzer S,Seuntjens J

更新日期：2014-04-01 00:00:00

abstract：PURPOSE:Transcranial magnetic resonance-guided focused ultrasound surgery is a noninvasive technique for causing selective tissue necrosis. Variations in density, thickness, and shape of the skull cause aberrations in the location and shape of the focal zone. In this paper, the authors propose a hybrid simulation-MR-AR...

journal_title：Medical physics

authors： Vyas U,Kaye E,Pauly KB

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:To develop and evaluate the impact on lesion conspicuity of a software-based x-ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x-ray scatter maps is incorporated. METHODS:A previously developed model of compressed breast shapes undergoing mamm...

journal_title：Medical physics

authors： Feng SS,D'Orsi CJ,Newell MS,Seidel RL,Patel B,Sechopoulos I

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:X-ray fluorescence (XRF) is a promising technique with sufficient specificity and sensitivity for identifying and quantifying features in small samples containing high atomic number (Z) materials such as iodine, gadolinium, and gold. In this study, the feasibility of applying XRF to early breast cancer diagnosi...

journal_title：Medical physics

authors： Ren L,Wu D,Li Y,Wang G,Wu X,Liu H

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:To investigate dosimetry for ocular brachytherapy for a range of eye plaque models containing(103)Pd, (125)I, or (131)Cs seeds with model-based dose calculations. METHODS:Five representative plaque models are developed based on a literature review and are compared to the standardized COMS plaque, including pla...

journal_title：Medical physics

authors： Lesperance M,Martinov M,Thomson RM

更新日期：2014-03-01 00:00:00

abstract：PURPOSE:The study aims to investigate whether Nakagami parameters--estimated from the statistical distribution of the backscattered ultrasound radio-frequency (RF) signals--could provide a means for quantitative characterization of parotid-gland injury resulting from head-and-neck radiotherapy. METHODS:A preliminary c...

journal_title：Medical physics

authors： Yang X,Tridandapani S,Beitler JJ,Yu DS,Wu N,Wang Y,Bruner DW,Curran WJ,Liu T

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:To evaluate the performance and efficacy for intensity inhomogeneity correction of various sequences of the human brain in 7T MRI using the extended version of the unified segmentation algorithm. MATERIALS:Ten healthy volunteers were scanned with four different sequences (2D spin echo [SE], 3D fast SE, 2D fast...

journal_title：Medical physics

authors： Uwano I,Kudo K,Yamashita F,Goodwin J,Higuchi S,Ito K,Harada T,Ogawa A,Sasaki M

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:In cardiac ablation therapy, accurate anatomic guidance is necessary to create effective tissue lesions for elimination of left atrial fibrillation. While fluoroscopy, ultrasound, and electroanatomic maps are important guidance tools, they lack information regarding detailed patient anatomy which can be obtaine...

journal_title：Medical physics

authors： Rettmann ME,Holmes DR 3rd,Kwartowitz DM,Gunawan M,Johnson SB,Camp JJ,Cameron BM,Dalegrave C,Kolasa MW,Packer DL,Robb RA

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:New technology has been developed to treat age-related macular degeneration (AMD) using 100 kVp pencil-beams that enter the patient through the radio-resistant sclera with a depth of interest between 1.6 and 2.6 cm. Measurement of reference and relative dose in a kilovoltage x-ray beam with a 0.42 cm diameter f...

journal_title：Medical physics

authors： Hanlon J,Chell E,Firpo M,Koruga I

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:The focus of this work was the demonstration and validation of VirtuaLinac with clinical photon beams and to investigate the implementation of low-Z targets in a TrueBeam linear accelerator (Linac) using Monte Carlo modeling. METHODS:VirtuaLinac, a cloud based web application utilizing Geant4 Monte Carlo code,...

journal_title：Medical physics

authors： Parsons D,Robar JL,Sawkey D

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:To describe a method for combining sliding window plans [intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT)] for use in treatment plan averaging, which is needed for Pareto surface navigation based multicriteria treatment planning. METHODS:The authors show that by taking an...

journal_title：Medical physics

authors： Craft D,Papp D,Unkelbach J

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:Currently, no 3D or 4D volumetric x-ray imaging techniques are available for intrafraction verification of target position during actual treatment delivery or in-between treatment beams, which is critical for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT) treatments. This study a...

journal_title：Medical physics

authors： Ren L,Zhang Y,Yin FF

更新日期：2014-02-01 00:00:00

abstract：PURPOSE:Tumor grading is an important part of breast cancer diagnosis and currently requires biopsy as its standard. Here, the authors investigate quantitative ultrasound parameters in locally advanced breast cancers that can potentially separate tumors from normal breast tissue and differentiate tumor grades. METHODS...

journal_title：Medical physics

authors： Tadayyon H,Sadeghi-Naini A,Wirtzfeld L,Wright FC,Czarnota G

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:External beam radiation therapy (EBRT) usually uses heterogeneous dose distributions in a given volume. Designing detectors for quality control of these treatments is still a developing subject. The size of the detectors should be small to enhance spatial resolution and ensure low perturbation of the beam. A hi...

journal_title：Medical physics

authors： Barbés B,Azcona JD,Burguete J,Martí-Climent JM

更新日期：2014-01-01 00:00:00

abstract：PURPOSE:The availability of accurate and simple models for the estimation of x-ray spectra is of great importance for system simulation, optimization, or inclusion of photon energy information into data processing. There is a variety of publicly available tools for estimation of x-ray spectra in radiology and mammograp...

journal_title：Medical physics

authors： Sisniega A,Desco M,Vaquero JJ

更新日期：2014-01-01 00:00:00