Estimation of organ doses from kilovoltage cone-beam CT imaging used during radiotherapy patient position verification.

abstract：:The computed tomography (CT) radiation dose to pediatric patients has received considerable attention recently. Moreover, it is important to be able to determine CT radiation doses for various patient sizes ranging from infants to large adults. The current AAPM protocol only measures CT radiation dose using a 16 cm ac...

journal_title：Medical physics

authors： Nickoloff EL,Dutta AK,Lu ZF

更新日期：2003-03-01 00:00:00

abstract：PURPOSE:To investigate the feasibility of using the high Zeff storage phosphor material BaFBrI:Eu2+ in conjunction with the low Zeff storage phosphor material KCl:Eu2+ for simultaneous proton dose and linear energy transfer (LET) measurements by 1) measuring the fundamental optical and dosimetric properties of BaFBrI:E...

journal_title：Medical physics

authors： Setianegara J,Mazur TR,Yang D,Li HH

更新日期：2021-02-01 00:00:00

abstract：OBJECTIVE:Carbon ion particle therapy delivers sharp Bragg's peaks, and hence can produce dose delivery of very high precision and conformality. To complement this characteristic, particle therapy centers implement a number of technologies unique to these centers, and are not commonly known to the medical physics commu...

journal_title：Medical physics

authors： Cernica G,Mun S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:For the past two decades, high-Z nanoparticles have been of high interest to improve the therapeutic outcomes of radiation therapy, especially for low-energy X-rays. Monte Carlo (MC) simulations have been used to evaluate the boost of dose deposition induced by Auger electrons near the nanoparticle surface, by ...

journal_title：Medical physics

authors： Poignant F,Monini C,Testa É,Beuve M

更新日期：2020-11-04 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:The purpose of this study was to detect and analyze anomalies between a large number of computed tomography (CT) scanners, tracked over time, utilized to collect human pulmonary CT data for a national multicenter study: chronic obstructive pulmonary disease genetic epidemiology study (COPDGene). METHODS:A cust...

journal_title：Medical physics

authors： Sieren JP,Newell JD,Judy PF,Lynch DA,Chan KS,Guo J,Hoffman EA

更新日期：2012-09-01 00:00:00

abstract：PURPOSE:Compton camera imaging (CCI) systems are currently under investigation for radiotherapy dose reconstruction and verification. The ability of such a system to provide real-time images during dose delivery will be limited by the computational speed of the image reconstruction algorithm. In this work, the authors ...

journal_title：Medical physics

authors： Mundy DW,Herman MG

更新日期：2011-01-01 00:00:00

abstract：PURPOSE:Melanoma is the most lethal of the three primary skin cancers, including also basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), which are less lethal. The accepted diagnosis process involves manually observing a suspicious lesion through a Dermascope (i.e., a magnifying glass), followed by a biopsy....

journal_title：Medical physics

authors： Basov S,Dankner Y,Weinstein M,Katzir A,Platkov M

更新日期：2020-11-01 00:00:00

abstract：PURPOSE:In CT-guided liver tumor ablation interventions, registration of a preoperative contrast-enhanced CT image to the intraoperative CT image is hypothesized to improve guidance. This is a highly challenging registration task due to differences in patient poses and large deformations, and therefore high registratio...

journal_title：Medical physics

authors： Gunay G,Luu MH,Moelker A,van Walsum T,Klein S

更新日期：2017-07-01 00:00:00

abstract：:A spread-out Bragg peak (SOBP) is used in proton beam therapy to create a longitudinal conformality of the required dose to the target. In order to create this effect in a passive beam scattering system, a variety of components must operate in conjunction to produce the desired beam parameters. We will describe how th...

journal_title：Medical physics

authors： Lu HM,Brett R,Engelsman M,Slopsema R,Kooy H,Flanz J

更新日期：2007-10-01 00:00:00

abstract：PURPOSE:Radiation treatments are trending toward delivering higher doses per fraction under stereotactic radiosurgery and hypofractionated treatment regimens. There is a need for accurate 3D in vivo patient dose verification using electronic portal imaging device (EPID) measurements. This work presents a model-based te...

journal_title：Medical physics

authors： Van Uytven E,Van Beek T,McCowan PM,Chytyk-Praznik K,Greer PB,McCurdy BM

更新日期：2015-12-01 00:00:00

abstract：PURPOSE:Dynamic 18 F-FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least-squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model p...

journal_title：Medical physics

authors： Ben Bouallègue F,Vauchot F,Mariano-Goulart D

更新日期：2019-03-01 00:00:00

abstract：:CEA TVS film is a therapy verification film that has been recently introduced in the North American market. This film features linear characteristic curves for photon energies from 137Cs to 18 MV as reported by Cheng and Das [Med. Phys. 23, 1225 (1996)]. In Saskatoon, TVS film was investigated for its application in t...

journal_title：Medical physics

authors： Cadman P

更新日期：1998-08-01 00:00:00

abstract：:The dose distribution for an ovoid with a new tungsten shielding design was determined using Monte Carlo simulation. Standard Cesium-137 tube sources, tungsten shielding, and aluminum ovoid applicator were each modeled as a collection of solid objects. Dose was calculated in planes above, below, in front of, and on th...

journal_title：Medical physics

authors： Weeks KJ

更新日期：1998-12-01 00:00:00

abstract：:The data from Meisberger et al. [Radiology 90, 953-957 (1968)] are often used as a basis for dose calculations in brachytherapy. In order to describe the absorbed dose in water around a brachytherapy point source, Meisberger provided a polynomial fit for different isotopes taking into account the effect of attenuation...

journal_title：Medical physics

authors： Tiourina TB,Dries WJ,van der Linden PM

更新日期：1995-05-01 00:00:00

abstract：PURPOSE:To investigate the inconsistency of recent literature on the effect of magnetic field on the response of radiochromic films, we studied the influence of 0.35 T magnetic field on dosimetric response of EBT3 and EBT-XD GafchromicTM films. METHODS:Two different models of radiochromic films, EBT3 and EBT-XD, were ...

journal_title：Medical physics

authors： Darafsheh A,Hao Y,Maraghechi B,Cammin J,Reynoso FJ,Khan R

更新日期：2020-09-01 00:00:00

abstract：PURPOSE:The image quality of dedicated cone beam breast CT (CBBCT) is limited by substantial scatter contamination, resulting in cupping artifacts and contrast-loss in reconstructed images. Such effects obscure the visibility of soft-tissue lesions and calcifications, which hinders breast cancer detection and diagnosis...

journal_title：Medical physics

authors： Shi L,Vedantham S,Karellas A,Zhu L

更新日期：2016-08-01 00:00:00

abstract：:Consensus has been developing over the past few decades on a number of measurements required for the laboratory assessment of medical imaging modalities. Nevertheless, understanding of the connection between these measurements and human observer performance in a broad range of tasks remains far from complete. Focusing...

journal_title：Medical physics

authors： Metz CE,Wagner RF,Doi K,Brown DG,Nishikawa RM,Myers KJ

更新日期：1995-07-01 00:00:00

abstract：PURPOSE:Automated segmentation could improve the efficiency of modeling-based pelvic organ prolapse (POP) evaluations. However, segmentation performance is limited by the blurry soft tissue boundaries. In this study, we aimed to present a hybrid solution for uterus, rectum, bladder, and levator ani muscle segmentation ...

journal_title：Medical physics

authors： Feng F,Ashton-Miller JA,DeLancey JOL,Luo J

更新日期：2020-09-01 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：PURPOSE:The performance of a newly developed, high resolution, microangiographic fluoroscope (MAF) (35 μm pixel pitch and 300 μm thick CsI phosphor) was evaluated using a generalized linear system analysis and compared with that of a standard amorphous Si thin film transistor flat panel detector (FPD) (194 μm pixel pit...

journal_title：Medical physics

authors： Jain A,Bednarek DR,Rudin S

更新日期：2013-03-01 00:00:00

abstract：:Total scalp irradiation is a treatment technique used for a variety of superficial malignancies. Helical tomotherapy is an effective technique used for total scalp irradiation. Recent published work has shown the TomoTherapy planning system to overestimate the superficial dose. In this study, the superficial doses for...

journal_title：Medical physics

authors： Hardcastle N,Soisson E,Metcalfe P,Rosenfeld AB,Tome WA

更新日期：2008-11-01 00:00:00

abstract：:Empirical functions that describe primary beam profiles for radiotherapy treatment planning systems generally account for finite source size only on beams unmodified by blocks, wedges, or compensating filters. To incorporate the effects of extended sources on such modified beams and to treat the effect of an extended ...

journal_title：Medical physics

authors： Starkschall G

更新日期：1988-09-01 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：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:The authors had previously published measurements of the detectability of disk-shaped contrast objects in images obtained from a C-arm CT system. A simple approach based on Rose's criterion was used to scale the date, assuming the threshold for the smallest diameter detected should be inversely proportional to ...

journal_title：Medical physics

authors： Ganguly A,Yoon S,Fahrig R

更新日期：2010-05-01 00:00:00

abstract：:In Monte Carlo simulations of light transport in tissues, a grid system is set up to score physical quantities. This study of cylindrically symmetrical problems found that the optimized radial and angular positions for the averaged physical quantities in each grid element are off-center. The error of the extrapolated ...

journal_title：Medical physics

authors： Wang L,Jacques SL

更新日期：1994-07-01 00:00:00

abstract：PURPOSE:Flattening filter free (FFF) beams generated by medical linear accelerators have recently started to be used in radiotherapy clinical practice. Such beams present fundamental differences with respect to the standard filter flattened (FF) beams, making the generally used dosimetric parameters and definitions not...

journal_title：Medical physics

authors： Fogliata A,Garcia R,Knoos T,Nicolini G,Clivio A,Vanetti E,Khamphan C,Cozzi L

更新日期：2012-10-01 00:00:00

abstract：:Reconstruction of electron spectra of medical accelerators from measured depth dose distributions is an attractive tool for commissioning of a Monte Carlo treatment planning system. However, the reconstruction method is an inverse radiation transport problem which is poorly conditioned, in the sense it may become unst...

journal_title：Medical physics

authors： Chvetsov AV,Sandison GA

更新日期：2002-04-01 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