A Monte-Carlo-based and GPU-accelerated 4D-dose calculator for a pencil beam scanning proton therapy system.

abstract：:We have made a comparative investigation of the estimated spectra obtained by the Laplace transform analysis of the transmitted exposure data measured in an absorption study of a 4-MV x-ray beam. Four transform pair models currently used with this method have been evaluated. It has been determined that the Archer-Wagn...

journal_title：Medical physics

authors： Ahuja SD,Steward PG,Roy TS,Slessinger ED

更新日期：1986-05-01 00:00:00

abstract：:An automated technique for the alignment of right and left breast images has been developed for use in the computerized analysis of bilateral breast images. In this technique, the breast region is first identified in each digital mammogram by use of histogram analysis and morphological filtering operations. The anteri...

journal_title：Medical physics

authors： Yin FF,Giger ML,Doi K,Vyborny CJ,Schmidt RA

更新日期：1994-03-01 00:00:00

abstract：:This paper examines the distributions of the SAR (specific absorption rate) ratio and temperature elevation when an ultrasound beam propagates through the interface of muscle and bone. This interface is regarded as a flat boundary to partition the energy of the ultrasound beam, and the analytical solution of temperatu...

journal_title：Medical physics

authors： Lin WL,Liauh CT,Chen YY,Liu HC,Shieh MJ

更新日期：2000-05-01 00:00:00

abstract：:Absorbed doses from main charged-particle beams and charged-particle fragments have been measured with high accuracy for particle therapy, but there are few reports for doses from neutron components produced as fragments. This study describes the measurements on neutron doses produced by carbon beams; microdosimetric ...

journal_title：Medical physics

authors： Endo S,Tanaka K,Takada M,Onizuka Y,Miyahara N,Sato T,Ishikawa M,Maeda N,Hayabuchi N,Shizuma K,Hoshi M

更新日期：2007-09-01 00:00:00

abstract：:A new energy selective detector for dual energy computed radiography has been developed that combines many of the advantages of x-ray tube voltage switching and single exposure double screen detectors. The new active detector utilizes electro-optical modulation of the response of the storage phosphor screens to allow ...

journal_title：Medical physics

authors： Alvarez RE

更新日期：1996-10-01 00:00:00

abstract：PURPOSE:The authors are developing a system for calibrated breast density measurements using full field digital mammography (FFDM). Breast tissue equivalent (BTE) phantom images are used to establish baseline (BL) calibration curves at time zero. For a given FFDM unit, the full BL dataset is comprised of approximately ...

journal_title：Medical physics

authors： Lu B,Smallwood AM,Sellers TA,Drukteinis JS,Heine JJ,Fowler EE

更新日期：2015-02-01 00:00:00

abstract：:The computational aspects of the design of an optical distance indicator (ODI) for use with a radiation therapy accelerator are discussed. The specifics of the optical and mechanical design of an ODI for use with a superconducting cyclotron used for fast neutron therapy are presented. ...

journal_title：Medical physics

authors： Maughan RL

更新日期：1999-02-01 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：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:Primary goal of this study is to select optimal registration schemes in the framework of interstitial lung disease (ILD) follow-up analysis in CT. METHODS:A set of 128 multiresolution schemes composed of multiresolution nonrigid and combinations of rigid and nonrigid registration schemes are evaluated, utilizi...

journal_title：Medical physics

authors： Vlachopoulos G,Korfiatis P,Skiadopoulos S,Kazantzi A,Kalogeropoulou C,Pratikakis I,Costaridou L

更新日期：2015-08-01 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:Anatomical variations occur during head and neck (H&N) radiotherapy treatment. kV cone-beam computed tomography (CBCT) images can be used for daily dose monitoring to assess dose variations owing to anatomic changes. Deep learning methods (DLMs) have recently been proposed to generate pseudo-CT (pCT) from CBCT ...

journal_title：Medical physics

authors： Barateau A,De Crevoisier R,Largent A,Mylona E,Perichon N,Castelli J,Chajon E,Acosta O,Simon A,Nunes JC,Lafond C

更新日期：2020-10-01 00:00:00

abstract：PURPOSE:To evaluate a simple, semi-automated lung mass estimation method on CT scans from a variety of acquisition techniques for mass correction of MIRD dose estimates. METHODS:CT scans from ten patients undergoing stereotactic body radiation therapy treatment planning on a GE DST PET/CT scanner were analyzed retrosp...

journal_title：Medical physics

authors： Busse N,Erwin W,Pan T

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:High-dose-rate brachytherapy (HDR-BT) is a treatment option for malignant skin diseases compared to external beam radiation therapy, HDR-BT provides improved target coverage, better organ sparing, and has comparable treatment times. This is especially true for large clinical targets with complex topologies. To ...

journal_title：Medical physics

authors： Guthier CV,Devlin PM,Harris TC,O'Farrell DA,Cormack RA,Buzurovic I

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:To develop and evaluate a tool for accurate, reproducible, and programmable motion control of imaging phantoms for use in motion sensitive magnetic resonance imaging (MRI) appli cations. METHODS:In this paper, the authors introduce a compact linear motion stage that is made of nonmagnetic material and is actua...

journal_title：Medical physics

authors： Tavallaei MA,Johnson PM,Liu J,Drangova M

更新日期：2016-01-01 00:00:00

abstract：:The use of Kumakhov capillary optics will significantly enhance the performance of near-monochromatic, Compton backscattered x-ray programs. The Vanderbilt University Medical Free-Electron Laser Center is developing the capability to create these tunable x rays for medical imaging. The present transport has only refle...

journal_title：Medical physics

authors： Tompkins PA,Abreu CC,Carroll FE,Xiao QF,MacDonald CA

更新日期：1994-11-01 00:00:00

abstract：:The photon energy spectrum emanating from a Leksell Gamma Knife, Model 23004B, was measured between 0.250 and 3.5 MeV with the sources exposed. Measurements were made using a 2x2 inch NaI detector enclosed in a lead-shielded apparatus having a 1/4 inch diameter measurement aperture, which reduced the amount of radiati...

journal_title：Medical physics

authors： Drzymala RE,Sohn JW,Guo C,Sobotka LG,Purdy JA

更新日期：2001-04-01 00:00:00

abstract：:Cone beam computed tomography (CBCT) is a relatively new patient imaging technique that has proved invaluable for treatment target verification and patient positioning during image-guided radiotherapy (IGRT). It has been shown that CBCT results in additional dose to bone that may amount to 10% of the prescribed dose. ...

journal_title：Medical physics

authors： Walters BR,Ding GX,Kramer R,Kawrakow I

更新日期：2009-07-01 00:00:00

abstract：:Quantification of transit time of a remote after-loading high dose rate (HDR) brachytherapy source is important both for accurate treatment planning and for quality assurance checks. In this investigation, an HDR-1000 well ionization chamber and a precision electrometer are used to measure the transit time of the Ir-1...

journal_title：Medical physics

authors： Sahoo N

更新日期：2001-08-01 00:00:00

abstract：:Knowledge of the relative intensity distribution at the patient's surface is essential for pencil beam calculations of three-dimensional dose distributions for arbitrarily shaped electron beams. To calculate the relative intensity distribution, the spatial spread resulting from angular spread is convolved with a two-d...

journal_title：Medical physics

authors： Mohan R,Chui CS,Fontenla D,Han K,Ballon D

更新日期：1988-03-01 00:00:00

abstract：:Neutron cross sections for nonelastic and elastic reactions on a range of elements have been evaluated for incident energies up to 150 MeV. These cross sections agree well with experimental cross section data for charged-particle production as well as neutron and photon production. Therefore they can be used to determ...

journal_title：Medical physics

authors： Chadwick MB,Barschall HH,Caswell RS,DeLuca PM,Hale GM,Jones DT,MacFarlane RE,Meulders JP,Schuhmacher H,Schrewe UJ,Wambersie A,Young PG

更新日期：1999-06-01 00:00:00

abstract：:Stereo x-ray radiography attracts increasing attention in major clinical applications. The purpose of this paper is to analyze the 3D localization error for breast biopsy procedures and provide guidelines for improving its accuracy. Our prototype is a CCD based digital stereo x-ray imaging system. The mathematical mod...

journal_title：Medical physics

authors： Jiang H,Liu H,Wang G,Chen W,Fajardo LL

更新日期：2000-05-01 00:00:00

abstract：PURPOSE:Two-dimensional antiscatter grids (2DASG) for cone beam computed tomography (CBCT) is a new area of research to reduce scatter intensity, and consequently improve CBCT image quality. One of the challenges in implementation of 2DASGs is their septa shadows that are impinged on the projections. If these artifacts...

journal_title：Medical physics

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

更新日期：2019-05-01 00:00:00

abstract：:Reported MOSFET measurements concern mostly external radiotherapy and in vivo dosimetry. In this paper, we apply the technique for absolute dosimetry in the context of HDR brachytherapy using an 192Ir source. Measured radial dose rate distributions in water for different planes perpendicular to the source axis are pre...

journal_title：Medical physics

authors： Zilio VO,Joneja OP,Popowski Y,Rosenfeld A,Chawla R

更新日期：2006-06-01 00:00:00

abstract：:An anthropomorphic 1H MRS head phantom has been developed which mimics the in vivo structure, metabolite concentrations, and relaxation times (for both water and metabolites) of human brain tissue. Different brain regions and two tumor types, fluid-containing ventricles, and air-filled sinus, and subcutaneous fat are ...

journal_title：Medical physics

authors： Rice JR,Milbrandt RH,Madsen EL,Frank GR,Boote EJ,Blechinger JC

更新日期：1998-07-01 00:00:00

abstract：:Dose to the total body from induced radiation resulting from primary exposure to radiotherapeutic beams is not detailed in routine treatment planning though this information is potentially important for better estimates of health risks including secondary cancers. This information can also allow better management of p...

journal_title：Medical physics

authors： Difilippo F,Papiez L,Moskvin V,Peplow D,DesRosiers C,Johnson J,Timmerman R,Randall M,Lillie R

更新日期：2003-10-01 00:00:00

abstract：PURPOSE:The local depth dose gradient and the displacement correction factor for Farmer-type ionization chambers are quantified for reference dosimetry at shallow depth in single-layer scanned proton fields. METHOD:Integrated radial profiles as a function of depth (IRPDs) measured at three proton therapy centers were ...

journal_title：Medical physics

authors： Palmans H,Medin J,Trnková P,Vatnitsky S

更新日期：2020-12-01 00:00:00

abstract：PURPOSE:High-intensity focused ultrasound (HIFU) has been investigated for ablative therapy and drug enhancement for gene therapy and chemotherapy. The aim of this work is to explore the feasibility of pulsed focused ultrasound (pFUS) for cancer therapy using an in vivo animal model. METHODS:A clinical HIFU system (In...

journal_title：Medical physics

authors： Ma CM,Chen X,Cvetkovic D,Chen L

更新日期：2014-12-01 00:00:00

abstract：PURPOSE:Formation of new blood vessels (angiogenesis) in response to hypoxia is a fundamental event in the process of tumor growth and metastatic dissemination. However, abnormalities in tumor neovasculature often induce increased interstitial pressure (IP) and further reduce oxygenation (pO2) of tumor cells. In radiot...

journal_title：Medical physics

authors： Lagerlöf JH,Kindblom J,Bernhardt P

更新日期：2011-08-01 00:00:00

abstract：PURPOSE:The purpose of this study was to evaluate the effect of various computed tomography (CT) thresholds on trapping volumetric measurements by multidetector CT in chronic obstructive pulmonary disease (COPD). METHODS:Twenty-three COPD patients were scanned with a 64-slice CT scanner in both the inspiratory and exp...

journal_title：Medical physics

authors： Wang X,Duan J,Du Y,Shen N,He B,Yuan H

更新日期：2013-08-01 00:00:00