Plan averaging for multicriteria navigation of sliding window IMRT and VMAT.

abstract：:This study compared air exposures during conventional dental and maxillofacial radiography and similar views using free-focus radiography with conventional image receptors. The results show that periapical type surveys on nonscreen film placed extraorally or in the buccal fold may be carried out with an exposure to th...

journal_title：Medical physics

authors： Jensen TW,Randall GJ,Goldberg AJ

更新日期：1980-07-01 00:00:00

abstract：PURPOSE:Several new technologies for single photon emission computed tomography (SPECT) instrumentation with parallel-hole collimation have been proposed to improve detector sensitivity and signal collection efficiency. Benefits from improved signal efficiency include shorter acquisition times and lower dose requiremen...

journal_title：Medical physics

authors： Lee TC,Ellin JR,Huang Q,Shrestha U,Gullberg GT,Seo Y

更新日期：2014-11-01 00:00:00

abstract：PURPOSE:To investigate the effect of energy (kVp) and filters (no filter, half Bowtie, and full Bowtie) on the dose response curves of the Gafchromic XRQA2 film and nanoDot optical stimulated luminescence dosimeters (OSLDs) in CBCT dose fields. To measure surface and internal doses received during x-ray volume imager (...

journal_title：Medical physics

authors： Giaddui T,Cui Y,Galvin J,Yu Y,Xiao Y

更新日期：2013-06-01 00:00:00

abstract：PURPOSE:This study aims to investigate the feasibility of using the images of the treatment fields acquired by an electronic portal imaging device (EPID) for real-time target localization. METHODS:Forty one patients treated with IMRT and RapidArc were recruited in this study including 37 prostate patients and 4 lung p...

journal_title：Medical physics

authors： Xu Q,Lin M,Chen X,Tong X,Fan J,Dong Z,Chen L,Ma C

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:Body composition is known to be associated with many diseases including diabetes, cancers, and cardiovascular diseases. In this paper, we developed a fully automatic body tissue decomposition procedure to segment three major compartments that are related to body composition analysis - subcutaneous adipose tissu...

journal_title：Medical physics

authors： Fu Y,Ippolito JE,Ludwig DR,Nizamuddin R,Li HH,Yang D

更新日期：2020-11-01 00:00:00

abstract：PURPOSE:Automatic breast ultrasound (ABUS) imaging has become an essential tool in breast cancer diagnosis since it provides complementary information to other imaging modalities. Lesion segmentation on ABUS is a prerequisite step of breast cancer computer-aided diagnosis (CAD). This work aims to develop a deep learnin...

journal_title：Medical physics

authors： Lei Y,He X,Yao J,Wang T,Wang L,Li W,Curran WJ,Liu T,Xu D,Yang X

更新日期：2020-10-30 00:00:00

abstract：PURPOSE:The recent introduction of digital tomosynthesis imaging into routine clinical use has enabled the acquisition of volumetric patient data within a standard radiographic examination. Tomosynthesis requires the acquisition of multiple projection views, requiring additional dose compared to a standard projection e...

journal_title：Medical physics

authors： Sabol JM

更新日期：2009-12-01 00:00:00

abstract：:A 4 x 500 mm2 "cloverleaf" low energy germanium detector array has been assembled for the purpose of in vivo bone lead measurement through x-ray fluorescence. Using 109Cd as an exciting source, results are reported from a leg phantom simulating measurement of lead in a human tibia. For high activity (4.0-4.4 GBq) and ...

journal_title：Medical physics

authors： Fleming DE,Mills CE

更新日期：2007-03-01 00:00:00

abstract：PURPOSE:The primary objective of this work is to measure the secondary neutron field produced by an uncollimated proton pencil beam impinging on different tissue-equivalent phantom materials using organic scintillation detectors. Additionally, the Monte Carlo code mcnpx-PoliMi was used to simulate the detector response...

journal_title：Medical physics

authors： Clarke SD,Pryser E,Wieger BM,Pozzi SA,Haelg RA,Bashkirov VA,Schulte RW

更新日期：2016-11-01 00:00:00

abstract：:Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-con...

journal_title：Medical physics

authors： Rong XJ,Shaw CC,Liu X,Lemacks MR,Thompson SK

更新日期：2001-11-01 00:00:00

abstract：PURPOSE:Total and regional body composition are important indicators of health and mortality risk, but their measurement is usually restricted to controlled environments in clinical settings with expensive and specialized equipment. A method that approaches the accuracy of the current gold standard method, dual-energy ...

journal_title：Medical physics

authors： Tian IY,Ng BK,Wong MC,Kennedy S,Hwaung P,Kelly N,Liu E,Garber AK,Curless B,Heymsfield SB,Shepherd JA

更新日期：2020-12-01 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:The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides exce...

journal_title：Medical physics

authors： Yang Y,Wang KK,Eslami S,Iordachita II,Patterson MS,Wong JW

更新日期：2015-04-01 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: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:At our institution, all proton patient plans undergo patient-specific quality assurance (PSQA) prior to treatment delivery. For intensity-modulated proton beam therapy, quality assurance is complex and time consuming, and it may involve multiple measurements per field. We reviewed our PSQA workflow and identifi...

journal_title：Medical physics

authors： Hernandez Morales D,Shan J,Liu W,Augustine KE,Bues M,Davis MJ,Fatyga M,Johnson JE,Mundy DW,Shen J,Younkin JE,Stoker JB

更新日期：2019-01-01 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 investigate narrow, elongated magnetically focused proton beams and compare their properties with passively collimated beams using Monte Carlo simulation. METHODS:We performed Geant4 Monte Carlo simulations involving a single quadrapole focusing magnet, thereby creating a flattened beam with an elongated e...

journal_title：Medical physics

authors： McAuley G,Barnes S,Wroe A,Slater J

更新日期：2012-06-01 00:00:00

abstract：:We are developing a computer program for automated detection of clustered microcalcifications on mammograms. In this study, we investigated the effectiveness of a signal classifier based on a convolution neural network (CNN) approach for improvement of the accuracy of the detection program. Fifty-two mammograms with c...

journal_title：Medical physics

authors： Chan HP,Lo SC,Sahiner B,Lam KL,Helvie MA

更新日期：1995-10-01 00:00:00

abstract：PURPOSE:To develop a novel aperture-based algorithm for volumetric modulated are therapy (VMAT) treatment plan optimization with high quality and high efficiency. METHODS:The VMAT optimization problem is formulated as a large-scale convex programming problem solved by a column generation approach. The authors consider...

journal_title：Medical physics

authors： Men C,Romeijn HE,Jia X,Jiang SB

更新日期：2010-11-01 00:00:00

abstract：:When parallel-plate chambers are used for dosimetry in electron fields, the AAPM dosimetry protocol recommends a value of 1.0 for the replacement correction factor, P(repl),pp,E, until further data become available. Here, P(repl),pp,E for five commercially available parallel-plate chambers was measured as a function o...

journal_title：Medical physics

authors： Reft CS,Kuchnir FT

更新日期：1991-11-01 00:00:00

abstract：:Magnetic resonance images can be compromised by constant frequency (CF) noise, such as radio frequency (RF) noise. We investigate the effects of CF noise in four imaging methods with non-uniform k-space sampling: single-shot echo-planar imaging (EPI) with sinusoidal readout gradients, phase-encoded echo-planar spectro...

journal_title：Medical physics

authors： Du W,Karczmar GS,Pan X

更新日期：2002-08-01 00:00:00

abstract：:Three Monte Carlo photon/electron transport codes (GEPTS, EGSnrc, and MCNP) are bench-marked against dose measurements in homogeneous (both low- and high-Z) media as well as at interfaces. A brief overview on physical models used by each code for photon and electron (positron) transport is given. Absolute calorimetric...

journal_title：Medical physics

authors： Chibani O,Li XA

更新日期：2002-05-01 00:00:00

abstract：:The effects of small cavities on dose in water and the dose in a homogeneous nonunit density medium illustrate that inhomogeneities do not act independently in photon dose perturbation, and serve as two constraints which should be satisfied by approximate methods of computed tomography (CT) pixel-based dose calculatio...

journal_title：Medical physics

authors： Wong JW,Henkelman RM

更新日期：1983-03-01 00:00:00

abstract：:A doorless entry system has been designed for use in high-energy radiation therapy rooms. The doorless entry improves patient access, safety and throughput, increases the physical safety for the radiation therapists, and avoids the significant cost of heavy shielding doors. The design meets concerns relating to radiat...

journal_title：Medical physics

authors： Dawson DJ,Wissing WW,Tonks RE

更新日期：1998-02-01 00:00:00

abstract：PURPOSE:The authors investigate the extent to which Response Evaluation Criteria in Solid Tumors (RECIST) can predict tumor volumes in ideal geometric settings and using clinical data. METHODS:The authors consider a hierarchy of models including uniaxial ellipsoids, general ellipsoids, and composites of ellipsoids, us...

journal_title：Medical physics

authors： Levine ZH,Galloway BR,Peskin AP,Heussel CP,Chen JJ

更新日期：2011-05-01 00:00:00

abstract：PURPOSE:The authors have developed a quantitative calibration method for a multileaf collimator (MLC) which measures individual leaf positions relative to the MLC backup jaw on an Elekta Synergy linear accelerator. METHODS:The method utilizes a commercially available two-axis detector array (Profiler 2; Sun Nuclear Co...

journal_title：Medical physics

authors： Simon TA,Kahler D,Simon WE,Fox C,Li J,Palta J,Liu C

更新日期：2009-10-01 00:00:00

abstract：PURPOSE:The repair rate conventionally assumed to be constant during the entire radiation course. However, increasing evidences from animal studies show that the repair process may slow down with time and the experimental data does not fit an exponential pattern. To address this enigma, we presented a generalized linea...

journal_title：Medical physics

authors： Huang Z,Mayr NA,Lo SS,McLawhorn R,Gao M,Liu T,Yuh W

更新日期：2012-06-01 00:00:00

abstract：:We believe that, for the purpose of evaluation and optimization of treatment plans, quasirandom sampling is superior to grid sampling and should be the method of choice. We believe it to be on average more efficient than grid sampling (i.e., more accurate for any given number of dose estimates) and, even more importan...

journal_title：Medical physics

authors： Niemierko A,Goitein M

更新日期：1993-09-01 00:00:00

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