On using 3D γ-analysis for IMRT and VMAT pretreatment plan QA.

abstract：:As a quality control procedure, a post-implant seed migration survey has been accomplished on 340 prostate cancer patients since November 2001. Pulmonary seed embolization and intracardiac seed embolization have been detected. A case of thyroid uptake due to leaking iodine-125 (I-125) sources was also seized. In order...

journal_title：Medical physics

authors： Chen QS,Russell JL Jr,Macklis RR,Weinhous MS,Blair HF

更新日期：2006-07-01 00:00:00

abstract：:Imaging parameters associated with a clinical magnetic resonance imaging (MRI) system, evaluated with the use of simple and inexpensive phantoms, are described in evaluation of a clinical MRI system. Images, obtained with a Diasonics 0.35-T MRI system using an elliptical whole-body radio frequency coil, are presented ...

journal_title：Medical physics

authors： Brateman L,Jennings LW,Nunnally RL,Vaughan JT

更新日期：1986-07-01 00:00:00

abstract：:Backscatter factors for kVps and half-value layers typical of mammographic beams have been determined as a function of beam diameter and half-value layer. The method utilized thin TLD-100 chips with the scattering medium alternately present and absent. Results indicate that the field-size dependence of the backscatter...

journal_title：Medical physics

authors： Dubuque GL,Cacak RK,Hendee WR

更新日期：1977-09-01 00:00:00

abstract：PURPOSE:The aim of this study was to develop a dose calculation method which is applicable to the interseed attenuation and the geometry lacking the equilibrium radiation scatter conditions in brachytherapy. METHODS:The dose obtained from measurement with a radiophotoluminescent glass rod dosimeter (GRD) was compared ...

journal_title：Medical physics

authors： Tanaka K,Tateoka K,Asanuma O,Kamo K,Bengua G,Sato K,Ueda T,Takeda H,Takagi M,Hareyama M,Takada J

更新日期：2011-06-01 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：:Cone beam transmission CT (CB-CT) improves SPECT imaging by providing high-quality attenuation maps for attenuation compensation and for correlated SPECT and CT imaging. The present work measures the detection nonuniformity for CB-CT implemented with a gamma camera, and applies nonuniformity corrections to make CB-CT ...

journal_title：Medical physics

authors： Manglos SH,Capone RB,Bassano DA

更新日期：1992-03-01 00:00:00

abstract：:Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure br...

journal_title：Medical physics

authors： Ducote JL,Molloi S

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:To investigate how the setting of optimization parameters, fractional dose and tuning structure in tomotherapy treatment planning affects plan dosimetric quality and treatment efficiency. METHODS:A digital phantom to simulate head and neck radiotherapy was constructed for this study. Tumor was 10cm long C-shap...

journal_title：Medical physics

authors： Lian J,Burkhardt K,Chera B,Chang S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:To develop a new design of an x-ray beam shaper for helical computed tomography (CT) that increases the dose utilization. METHODS:For typical reconstruction algorithms in helical CT, different data are utilized with different weights during back-projection. In particular, data of the outer detector rows, i.e.,...

journal_title：Medical physics

authors： Köhler T,Brendel B,Proksa R

更新日期：2011-07-01 00:00:00

abstract：:A measurement technique previously proposed for determining dose from primary radiation has been tested using 60Co gamma rays. It is shown that the dose from primary radiation is reliably determined for field sizes of 10 X 10 and 20 X 20 cm2 at depths of 0.5, 5, and 10 cm in water. With further development this techni...

journal_title：Medical physics

authors： Nizin PS,Kase KR

更新日期：1990-01-01 00:00:00

abstract：:In patients with lymphoma, identification and quantification of the tumor extent on serial CT examinations is critical for assessing tumor response to therapy. In this paper, we present a computer method to automatically match and segment lymphomas in follow-up CT images. The method requires that target lymph nodes in...

journal_title：Medical physics

authors： Yan J,Zhao B,Curran S,Zelenetz A,Schwartz LH

更新日期：2007-01-01 00:00:00

abstract：:The purpose of this work is to demonstrate a proof of feasibility of the application of a commercial prototype deformable model algorithm to the problem of delineation of anatomic structures on four-dimensional (4D) computed tomography (CT) image data sets. We acquired a 4D CT image data set of a patient's thorax that...

journal_title：Medical physics

authors： Ragan D,Starkschall G,McNutt T,Kaus M,Guerrero T,Stevens CW

更新日期：2005-07-01 00:00:00

abstract：:Both the design considerations and the dosimetric properties of the Siemens Model 5800 linear accelerator are discussed. This unit is of such an energy (3.3 MV) as to imitate Cobalt-60 teletherapy depth doses. A linear relation of dmax to depth dose at low energies was found for various wave guides and targets. The en...

journal_title：Medical physics

authors： Steidley KD,Rosen CW

更新日期：1990-05-01 00:00:00

abstract：PURPOSE:High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly (192)Ir with an air KERMA strength range between 20,000 and 40,000 U, where 1 U = 1 μGy m(2)/h in a...

journal_title：Medical physics

authors： Espinoza A,Beeksma B,Petasecca M,Fuduli I,Porumb C,Cutajar D,Corde S,Jackson M,Lerch ML,Rosenfeld AB

更新日期：2013-11-01 00:00:00

abstract：PURPOSE:This article presents an iterative method for compensation of motion artifacts for slowly rotating computed tomography (CT) systems. Patient's motion introduces inconsistencies among projections and yields severe reconstruction artifacts for free-breathing acquisitions. Streaks and doubling of structures can ap...

journal_title：Medical physics

authors： Schretter C,Rose G,Bertram M

更新日期：2009-11-01 00:00:00

abstract：:A scintillation dosemeter is calibrated for 90Sr/90Y beta rays from an ophthalmic applicator, using an extrapolation ionization chamber as a reference instrument. The calibration factor for the scintillation dosemeter agrees with that given by the manufacturer of the dosemeter within ca. 2%. The estimated overall unce...

journal_title：Medical physics

authors： Hakanen AT,Sipilä PM,Kosunen A

更新日期：2004-05-01 00:00:00

abstract：BACKGROUND:Deep learning methods for radiomics/computer-aided diagnosis (CADx) are often prohibited by small datasets, long computation time, and the need for extensive image preprocessing. AIMS:We aim to develop a breast CADx methodology that addresses the aforementioned issues by exploiting the efficiency of pre-tra...

journal_title：Medical physics

authors： Antropova N,Huynh BQ,Giger ML

更新日期：2017-10-01 00:00:00

abstract：:Human tumors are characterized by an abnormal vascular network that develops because of unregulated angiogenesis. This contributes to abnormalities of the tumor microenvironment like hypoxia, acidosis and high interstitial fluid pressure that influence treatment response and patient survival. There is an important cli...

journal_title：Medical physics

authors： Milosevic M

更新日期：2012-06-01 00:00:00

abstract：:Hyperthermia, as an adjuvant with radiation and chemotherapy, has shown promise in the treatment of cancer. The relevant biological effects of a hyperthermia treatment are both time and temperature-dependent, creating a need for accurate thermometry. We present a novel noninvasive thermometry modality that combines a ...

journal_title：Medical physics

authors： Dreher MR,Elas M,Ichikawa K,Barth ED,Chilkoti A,Rosen GM,Halpern HJ,Dewhirst M

更新日期：2004-10-01 00:00:00

abstract：:An indirect flat-panel imager (FPI) with avalanche gain is being investigated for low-dose x-ray imaging. It is made by optically coupling a structured x-ray scintillator CsI(Tl) to an amorphous selenium (a-Se) avalanche photoconductor called HARP (high-gain avalanche rushing photoconductor). The final electronic imag...

journal_title：Medical physics

authors： Zhao W,Li D,Reznik A,Lui BJ,Hunt DC,Rowlands JA,Ohkawa Y,Tanioka K

更新日期：2005-09-01 00:00:00

abstract：PURPOSE:Micro-CT is widely used for small animal imaging in preclinical studies of cardiopulmonary disease, but further development is needed to improve spatial resolution, temporal resolution, and material contrast. We present a technique for visualizing the changing distribution of iodine in the cardiac cycle with du...

journal_title：Medical physics

authors： Johnston SM,Johnson GA,Badea CT

更新日期：2012-08-01 00:00:00

abstract：PURPOSE:To develop a hypothesis-generating framework for automatic extraction of dose-outcome relationships from an in-house, analytic oncology database. METHODS:Dose-volume histograms (DVH) and clinical outcomes have been routinely stored to the authors' database for 684 head and neck cancer patients treated from 200...

journal_title：Medical physics

authors： Robertson SP,Quon H,Kiess AP,Moore JA,Yang W,Cheng Z,Afonso S,Allen M,Richardson M,Choflet A,Sharabi A,McNutt TR

更新日期：2015-07-01 00:00:00

abstract：PURPOSE:In this work the performance of a compact multiresolution and multicontrast x-ray phase system based on edge illumination is investigated. It has been designed for small animal imaging and with a limited footprint for ease of deployment in laboratories. METHODS:The presented edge illumination system is based o...

journal_title：Medical physics

authors： Massimi L,Meganck JA,Towns R,Olivo A,Endrizzi M

更新日期：2020-10-27 00:00:00

abstract：PURPOSE:To evaluate both the Calypso Systems' (Calypso Medical Technologies, Inc., Seattle, WA) localization accuracy in the presence of wireless metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters of dose verification system (DVS, Sicel Technologies, Inc., Morrisville, NC) and the dosimeters' reading...

journal_title：Medical physics

authors： Su Z,Zhang L,Ramakrishnan V,Hagan M,Anscher M

更新日期：2011-05-01 00:00:00

abstract：PURPOSE:A dynamic bowtie filter can modulate flux along both fan and view angles for reduced patient dose, scatter, and required photon flux, which is especially important for photon counting detectors (PCDs). Among the proposed dynamic bowtie designs, the piecewise-linear attenuator (Hsieh and Pelc, Med Phys. 2013;40:...

journal_title：Medical physics

authors： Shunhavanich P,Hsieh SS,Pelc NJ

更新日期：2019-01-01 00:00:00

abstract：:This investigation contains the results of exposure measurements on two types of clinical I-125 seeds: a model 6702 no-marker seed, and a model 6711 silver wire seed. Measurements were made locally with a parallel-plate mammography chamber, traceable to the National Bureau of Standards (NBS) calibration. The same seed...

journal_title：Medical physics

authors： Kubo H

更新日期：1985-03-01 00:00:00

abstract：OBJECTIVES:To evaluate the performance of RapidArc® (Eclipse 10.0.28) and SmartArc® (Pinnacle 9.0) radiotherapy plans for lung stereotactic body radiation therapy (SBRT) in terms of dosimetric plan quality, delivery efficiency, inhomogeneity corrections and accuracy of dose delivery using a custom-built heterogeneity i...

journal_title：Medical physics

authors： Fakir H,Hoover D,Chen JZ

更新日期：2012-07-01 00:00:00

abstract：PURPOSE:The aim of this study is to understand the characteristics of secondary electrons generated from the interaction of gold nanoparticles (GNPs) with x-rays as a function of nanoparticle size and beam energy and thereby further the understanding of GNP-enhanced radiotherapy. METHODS:The effective range, deflectio...

journal_title：Medical physics

authors： Leung MK,Chow JC,Chithrani BD,Lee MJ,Oms B,Jaffray DA

更新日期：2011-02-01 00:00:00

abstract：:In this study, BrachyDose, a recently developed EGSnrc Monte Carlo code for rapid brachytherapy dose calculations, has been benchmarked by reproducing previously published dosimetry parameters for three brachytherapy seeds with varied internal structure and encapsulation. Calculations are performed for two 125I seeds ...

journal_title：Medical physics

authors： Taylor RE,Yegin G,Rogers DW

更新日期：2007-02-01 00:00:00

abstract：PURPOSE:To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. METHODS:Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was...

journal_title：Medical physics

authors： Hoppe ME,Schmidt TG

更新日期：2012-06-01 00:00:00