Transient noise characterization and filtration in CCD cameras exposed to stray radiation from a medical linear accelerator.

abstract：:The validity of conclusions drawn from multi-institutional radiotherapy studies is dependent upon the degree to which participating hospitals adhere to study requirements. A major effort undertaken by the Quality Assurance Review Center (QARC) assesses whether or not patient data which are deemed evaluable actually co...

journal_title：Medical physics

authors： Reinstein LE,McShan D,Glicksman AS

更新日期：1982-03-01 00:00:00

abstract：:Linac calibration is done in water, but patients are comprised primarily of soft tissue. Conceptually, and specified in NRG/RTOG trials, dose should be reported as dose-to-muscle to describe the dose to the patient. Historically, the dose-to-water of the linac calibration was often converted to dose-to-muscle for pati...

journal_title：Medical physics

authors： Kry SF,Feygelman V,Balter P,Knöös T,Charlie Ma CM,Snyder M,Tonner B,Vassiliev ON

更新日期：2020-03-01 00:00:00

abstract：PURPOSE:Because the small-radius photon beams shaped by cones in stereotactic radiosurgery (SRS) lack lateral electronic equilibrium and a detector's finite cross section, direct experimental measurement of dosimetric data for these beams can be subject to large uncertainties. As the dose calculation accuracy of a trea...

journal_title：Medical physics

authors： Yang JN,Ding X,Du W,Pino R

更新日期：2010-10-01 00:00:00

abstract：:A method to correct for geometric image distortion in the x-ray imaging chain, so-called dewarping, has been developed. A global two-dimensional polynomial model of which the degree is optimized is used. The performance of the method has been tested in a number of experiments using images of a plate with a 1 cm spaced...

journal_title：Medical physics

authors： Gronenschild E

更新日期：1997-12-01 00:00:00

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:Incorporating training into image segmentation is a good approach to achieve additional robustness. This work aims to develop an effective strategy to utilize shape prior knowledge, so that the segmentation label evolution can be driven toward the desired global optimum. METHODS:In the variational image segmen...

journal_title：Medical physics

authors： Zhao T,Ruan D

更新日期：2016-05-01 00:00:00

abstract：PURPOSE:To provide results of water calorimetry and ion chamber measurements in high-energy electron beams carried out at the National Research Council Canada (NRC). There are three main aspects to this work: (a) investigation of the behavior of ionization chambers in electron beams of different energies with focus on ...

journal_title：Medical physics

authors： Muir BR,Cojocaru CD,McEwen MR,Ross CK

更新日期：2017-10-01 00:00:00

abstract：PURPOSE:A series of examples are presented in which potential errors in the delivery of radiation therapy were prevented through use of incident learning. These examples underscore the value of reporting near miss incidents. METHODS:Using a departmental incident learning system, eight incidents were noted over a two-y...

journal_title：Medical physics

authors： Ford EC,Smith K,Harris K,Terezakis S

更新日期：2012-11-01 00:00:00

abstract：:In this paper, we present a unified framework to reconstruct images for both fan beam and cone beam projections. The important feature of our theoretical framework is that it does not depend on the classical concept of the Radon transform at all. This property allows us to directly generalize the ideas and techniques ...

journal_title：Medical physics

authors： Chen GH

更新日期：2003-06-01 00:00:00

abstract：PURPOSE:This study introduces a new hybrid ZTE/Dixon MR-based attenuation correction (MRAC) method including bone density estimation for PET/MRI and quantifies the effects of bone attenuation on metastatic lesion uptake in the pelvis. METHODS:Six patients with pelvic lesions were scanned using fluorodeoxyglucose (18F-...

journal_title：Medical physics

authors： Leynes AP,Yang J,Shanbhag DD,Kaushik SS,Seo Y,Hope TA,Wiesinger F,Larson PE

更新日期：2017-03-01 00:00:00

abstract：:Using high-energy photon and electron beams, the response of two solid water parallel-plate chambers is evaluated against a PTW (Physicallsch-Technische Werkstatten) Farmer-type chamber. These two chambers are (1) a Memorial "Holt" chamber which was further modified by this author to take advantage of electrically con...

journal_title：Medical physics

authors： Kubo H

更新日期：1993-03-01 00:00:00

abstract：PURPOSE:To quantify the inter fraction variation of spatial location of high dose regions of OARs in MR-image based cervix brachytherapy using rigid registration algorithm. METHODS:Retrospective analysis of 27 previously treated patients under EMBRACE multi-centric trial was evaluated. Each patient had two application...

journal_title：Medical physics

authors： Swamidas J,Mahantshetty U,Deshpande D,Shrivastava S

更新日期：2012-06-01 00:00:00

abstract：PURPOSE:The purpose of this work was to examine the suitability of VIPARnd polymer gel-9.4 T magnetic resonance microimaging system for high spatial resolution dose distribution measurements. METHODS:The VIPARnd samples (3 cm in outside diameter and 12 cm in height) were exposed to ionizing radiation by using a linear...

journal_title：Medical physics

authors： Skorupa A,Woźnica A,Ciszek M,Staniszewski M,Kijonka M,Kozicki M,Woźniak B,Orlef A,Polański A,Boguszewicz Ł,Sokół M

更新日期：2020-08-01 00:00:00

abstract：PURPOSE:To investigate how using different sets of decision criteria impacts the quality of intensity modulated radiation therapy (IMRT) plans obtained by multiobjective optimization. METHODS:A multiobjective optimization evolutionary algorithm (MOEA) was used to produce sets of IMRT plans. The MOEA consisted of two i...

journal_title：Medical physics

authors： Holdsworth C,Stewart RD,Kim M,Liao J,Phillips MH

更新日期：2011-06-01 00:00:00

abstract：:A Monte Carlo study of dosimetry for eye plaque brachytherapy is performed. BrachyDose, an EGSnrc user code which makes use of Yegin's multi-geometry package, is used to fully model I125 (model 6711) and Pd103 (model 200) brachytherapy seeds and the standardized plaques of the Collaborative Ocular Melanoma Study (COMS...

journal_title：Medical physics

authors： Thomson RM,Taylor REP,Rogers DWO

更新日期：2008-12-01 00:00:00

abstract：PURPOSE:It is estimated that 7% of women in the western world will develop palpable breast cysts in their lifetime. Even though cysts have been correlated with risk of developing breast cancer, many of them are benign and do not require follow-up. We develop a method to discriminate benign solitary cysts from malignant...

journal_title：Medical physics

authors： Kooi T,van Ginneken B,Karssemeijer N,den Heeten A

更新日期：2017-03-01 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：:Wireless capsule endoscopy (WCE) is a powerful tool for medical screening and diagnosis, where a small capsule is swallowed and moved by means of natural peristalsis and gravity through the human gastrointestinal (GI) tract. The camera-integrated capsule allows for visualization of the small intestine, a region which ...

journal_title：Medical physics

authors： Shamsudhin N,Zverev VI,Keller H,Pane S,Egolf PW,Nelson BJ,Tishin AM

更新日期：2017-08-01 00:00:00

abstract：PURPOSE:We report on the development of the open-source cross-platform radiation treatment planning toolkit matRad and its comparison against validated treatment planning systems. The toolkit enables three-dimensional intensity-modulated radiation therapy treatment planning for photons, scanned protons and scanned carb...

journal_title：Medical physics

authors： Wieser HP,Cisternas E,Wahl N,Ulrich S,Stadler A,Mescher H,Müller LR,Klinge T,Gabrys H,Burigo L,Mairani A,Ecker S,Ackermann B,Ellerbrock M,Parodi K,Jäkel O,Bangert M

更新日期：2017-06-01 00:00:00

abstract：PURPOSE:Theoretical reasoning suggests that direct conversion digital x-ray detectors based upon photoconductive amorphous-selenium (a-Se) could attain very high values of the MTF (modulation transfer function) at spatial frequencies well beyond 20 cycles mm(-1). One of the fundamental factors affecting resolution loss...

journal_title：Medical physics

authors： Hunter DM,Belev G,Kasap S,Yaffe MJ

更新日期：2012-02-01 00:00:00

abstract：BACKGROUND AND PURPOSE:The purpose of this study is to develop a deep learning-based approach to simultaneously segment five pelvic organs including prostate, bladder, rectum, left and right femoral heads on cone-beam CT (CBCT), as required elements for prostate adaptive radiotherapy planning. MATERIALS AND METHODS:We...

journal_title：Medical physics

authors： Fu Y,Lei Y,Wang T,Tian S,Patel P,Jani AB,Curran WJ,Liu T,Yang X

更新日期：2020-08-01 00:00:00

abstract：:In the present investigation, the necessary tests for implementing a quality assurance program for a commercial treatment planning system (TPS), recently installed at Sao Paulo University School of Medicine Clinicas Hospital-Brazil, was established and performed in accordance with the new IAEA publication TRS 430, and...

journal_title：Medical physics

authors： Camargo PR,Rodrigues LN,Furnari L,Rubo RA

更新日期：2007-07-01 00:00:00

abstract：PURPOSE:Two-dimensional ultrasound (2D US) imaging is commonly used for diagnostic and intraoperative guidance of interventional liver procedures; however, 2D US lacks volumetric information that may benefit interventional procedures. Over the past decade, three-dimensional ultrasound (3D US) has been developed to prov...

journal_title：Medical physics

authors： Neshat H,Cool DW,Barker K,Gardi L,Kakani N,Fenster A

更新日期：2013-11-01 00:00:00

abstract：:The purpose of this paper is to develop a method that reduces the number of segments for intensity modulated arc therapy (IMAT) and intensity modulated radiotherapy (IMRT) for concave target volumes (TV). The aim was to utilize no more than two intensity levels per organ at risk (OAR) and to derive both optimal segmen...

journal_title：Medical physics

authors： Bratengeier K

更新日期：2005-03-01 00:00:00

abstract：PURPOSE:Quantitative SPECT imaging is limited by many factors, including penetration of high energy photons through the collimator. Even small peaks of high energy yield extensive contamination in the photopeak energy window. Rotating slat collimators typically offer a 40- to 50-fold increase in geometric detection eff...

journal_title：Medical physics

authors： Van Holen R,Staelens S,Vandenberghe S

更新日期：2009-09-01 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：PURPOSE:In this report, the authors introduce the general concept of the completeness map, as a means to evaluate the completeness of data acquired by a given CT system design (architecture and scan mode). They illustrate the utility of completeness map by applying the completeness map concept to a number of candidate ...

journal_title：Medical physics

authors： Liu B,Bennett J,Wang G,De Man B,Zeng K,Yin Z,Fitzgerald P,Yu H

更新日期：2012-05-01 00:00:00

abstract：PURPOSE:Removal of the linear accelerator (linac) flattening filter enables a high rate of dose deposition with reduced treatment time. When used for megavoltage imaging, an unflat beam has reduced primary beam scatter resulting in sharper images. In fluoroscopic imaging mode, the unflat beam has higher photon count pe...

journal_title：Medical physics

authors： Christensen JD,Kirichenko A,Gayou O

更新日期：2013-08-01 00:00:00

abstract：PURPOSE:The feasibility of magnetic resonance image (MRI)-based proton therapy is based, among several other factors, on the implementation of appropriate extensions on current dose calculation methods. This work aims to develop a pencil beam algorithm (PBA) for dose calculation of proton beams within magnetic field re...

journal_title：Medical physics

authors： Padilla-Cabal F,Georg D,Fuchs H

更新日期：2018-05-01 00:00:00

abstract：PURPOSE:We investigated the feasibility of using simpler methods than manual whole-organ volume-of-interest (VOI) definition to estimate the organ activity concentration in single photon emission computed tomography (SPECT) in cases where the activity in the organ can be assumed to be uniformly distributed on the scale...

journal_title：Medical physics

authors： Vicente EM,Lodge MA,Rowe SP,Wahl RL,Frey EC

更新日期：2017-05-01 00:00:00