Accurate measurement of characteristic curves of II-TV digital systems by use of aluminum stepwedge technique.

Abstract:

:In order to determine accurately the relative x-ray intensities transmitted through the different steps of an aluminum stepwedge and incident on an image intensifier (II)-TV digital system, we used a 100-mm camera which was attached to the II output. The characteristic curves of an II-TV digital system, which relate the output pixel value to the input relative x-ray intensity, were determined at 65 and 90 kV by the use of the aluminum attenuation curves measured at the two energies. We found that the two curves agreed within the experimental errors; this result indicates that the characteristic curve does not depend on the x-ray beam quality used. Furthermore, for accurate measurement of the characteristic curve, it is necessary to collimate the x-ray beams to a narrow width, approximately 0.6 X 10 cm, so that the effect of veiling glare from the thinner to the thicker parts of the stepwedge is eliminated.

journal_name

Med Phys

journal_title

Medical physics

authors

Fujita H,Doi K

doi

10.1118/1.595819

subject

Has Abstract

pub_date

1986-11-01 00:00:00

pages

922-4

issue

6

eissn

0094-2405

issn

2473-4209

journal_volume

13

pub_type

杂志文章
  • A mouse radiation-induced liver disease model for stereotactic body radiation therapy validated in patients with hepatocellular carcinoma.

    abstract:PURPOSE:Lower radiation tolerance of the whole liver hinders dose escalations of stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) treatment. This study was conducted to define the exact doses that result in radiation-induced liver disease (RILD) as well as to determine dose constraints for t...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4953831

    authors: Wu ZF,Zhang JY,Shen XY,Zhou LY,Gao YB,Hu Y,Zeng ZC

    更新日期:2016-07-01 00:00:00

  • SU-E-T-300: Monte Carlo Simulation of Single-Plane Magnetically Focused Narrow Proton Beams.

    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

    pub_type: 杂志文章

    doi:10.1118/1.4735386

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

    更新日期:2012-06-01 00:00:00

  • Noninvasive eye localization in ocular proton therapy through optical eye tracking: A proof of concept.

    abstract:PURPOSE:Over the last four decades, Ocular Proton Therapy has been successfully used to treat patients affected by intraocular lesions. For this, treatment geometry verification is routinely performed using radiographic images to align a configuration of fiducial radiopaque markers implanted on the sclera outer surface...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.12841

    authors: Via R,Hennings F,Fattori G,Fassi A,Pica A,Lomax A,Weber DC,Baroni G,Hrbacek J

    更新日期:2018-05-01 00:00:00

  • A method for determining multileaf collimator transmission and scatter for dynamic intensity modulated radiotherapy.

    abstract::The main purpose of this work is to demonstrate a practical means of determining the leaf transmission and scatter characteristics of a multileaf collimator (MLC) pertinent to the commissioning of dynamic intensity modulated radiotherapy, especially for the sweeping window technique. The data are necessary for the con...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.1312190

    authors: Arnfield MR,Siebers JV,Kim JO,Wu Q,Keall PJ,Mohan R

    更新日期:2000-10-01 00:00:00

  • Toward a statistically relevant calibration end point for prostate seed implants.

    abstract::Interstitial brachytherapy for carcinoma of the prostate is achieved through the use of a configuration of radioactive seeds placed in a manner that delivers a customized, reasonably uniform dose to the target volume. Accurate dose delivery depends on both precise seed placement and reliable seed strength in the impla...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598877

    authors: Rosenzweig DP,Schell MC,Yu Y

    更新日期:2000-01-01 00:00:00

  • The line spread function and modulation transfer function of a computed tomographic scanner.

    abstract::A simple method to measure the line spread function of computed tomographic scanners has been developed. The line spread function of the EMI-Scanner was measured and the MTF of the scanner was calculated. The reproducibility of the method indicated this technique could be utilized to compare the spatial resolution of ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.594283

    authors: Judy PF

    更新日期:1976-07-01 00:00:00

  • Measurement of energy dependence for XRCT radiochromic film.

    abstract::Gafchromic XRCT, radiochromic film is assessed over a broad energy range, from kilovoltage to megavoltage x rays for variations in reflected optical density to dose response. A large energy dependence was found with reflected optical density output for the same delivered dose varying from 7.8 +/- 0.35 at 25.5 keV (50 ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.2219330

    authors: Butson MJ,Cheung T,Yu PK

    更新日期:2006-08-01 00:00:00

  • An outlook on x-ray CT research and development.

    abstract::Over the past decade, computed tomography (CT) theory, techniques and applications have undergone a rapid development. Since CT is so practical and useful, undoubtedly CT technology will continue advancing biomedical and non-biomedical applications. In this outlook article, we share our opinions on the research and de...

    journal_title:Medical physics

    pub_type: 杂志文章,评审

    doi:10.1118/1.2836950

    authors: Wang G,Yu H,De Man B

    更新日期:2008-03-01 00:00:00

  • Feasibility of MRI-only treatment planning for proton therapy in brain and prostate cancers: Dose calculation accuracy in substitute CT images.

    abstract:PURPOSE:Magnetic resonance imaging (MRI) is increasingly used for radiotherapy target delineation, image guidance, and treatment response monitoring. Recent studies have shown that an entire external x-ray radiotherapy treatment planning (RTP) workflow for brain tumor or prostate cancer patients based only on MRI refer...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4958677

    authors: Koivula L,Wee L,Korhonen J

    更新日期:2016-08-01 00:00:00

  • Evaluation of the local dose enhancement in the combination of proton therapy and nanoparticles.

    abstract:PURPOSE:The outcome of radiotherapy can be further improved by combining irradiation with dose enhancers such as high-Z nanoparticles. Since 2004, spectacular results have been obtained when low-energy x-ray irradiations have been combined with nanoparticles. Recently, the same combination has been explored in hadron t...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4934370

    authors: Martínez-Rovira I,Prezado Y

    更新日期:2015-11-01 00:00:00

  • Experimental test of theoretical models for time-resolved reflectance.

    abstract::Four different expressions, derived from the diffusion theory or the random walk model, were used to fit time-resolved reflectance data for the evaluation of tissue optical properties. The experimental reflectance curves were obtained from phantoms of known optical parameters (absorption and transport scattering coeff...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.597739

    authors: Cubeddu R,Pifferi A,Taroni P,Torricelli A,Valentini G

    更新日期:1996-09-01 00:00:00

  • Computerized radiographic texture measures for characterizing bone strength: a simulated clinical setup using femoral neck specimens.

    abstract::We are investigating computerized methods to ultimately characterize bone trabecular pattern from clinical skeletal radiographs. In this paper, we present a "phantom" for potential use in the development and evaluation of computerized methods for characterizing radiographic trabecular patterns and ultimately bone stre...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.598743

    authors: Chinander MR,Giger ML,Martell JM,Jiang C,Favus MJ

    更新日期:1999-11-01 00:00:00

  • Energy spectrum based calculation of the half and the tenth value layers for brachytherapy sources using a semiempirical parametrized mass attenuation coefficient formulism.

    abstract::As different types of radionuclides (e.g., 131Cs source) are introduced for clinical use in brachytherapy, the question is raised regarding whether a relatively simple method exists for the derivation of values of the half value layer (HVL) or the tenth value layer (TVL). For the radionuclide that has been clinically ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.2905356

    authors: Yue NJ

    更新日期:2008-06-01 00:00:00

  • Assessment of image quality and scatter and leakage radiation of an integrated MR-LINAC system.

    abstract:PURPOSE:To assess the image quality, scatter, and leakage radiation of an integrated magnetic resonance linear accelerator (MR-LINAC or MRL) system. METHODS:A large American College of Radiology (ACR) magnetic resonance imaging (MRI) accreditation phantom was used to evaluate the MRI capabilities of the integrated MRL...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.12767

    authors: Wang J,Yung J,Kadbi M,Hwang K,Ding Y,Ibbott GS

    更新日期:2018-03-01 00:00:00

  • Correcting magnetic resonance k-space data for in-plane motion using an optical position tracking system.

    abstract:PURPOSE:Motion is a major confound of image quality in MRI. A method of retrospectively correcting the effects of rotations and translations on the acquired k-space data is presented. METHODS:In two phantom experiments of well-controlled translation and rotation, two MRI-compatible infrared cameras recorded motion dat...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.3254189

    authors: Marxen M,Marmurek J,Baker N,Graham SJ

    更新日期:2009-12-01 00:00:00

  • Evaluation of carbon nanotube x-ray source array for stationary head computed tomography.

    abstract:PURPOSE:Stationary computed tomography (s-CT) conceptually offers several advantages over existing rotating gantry-based CT. Over the last 40 yr, s-CT has been investigated using different technological approaches. We are developing a s-CT system specifically for head/brain imaging using carbon nanotube (CNT)-based fie...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.14696

    authors: Spronk D,Luo Y,Inscoe CR,Lee YZ,Lu J,Zhou O

    更新日期:2020-12-31 00:00:00

  • An optimization algorithm for 3D real-time lung tumor tracking during arc therapy using kV projection images.

    abstract:PURPOSE:To develop a real-time markerless 3D tumor tracking using kilovoltage (kV) cone-beam CT (CBCT) projection images during volumetric modulated arc therapy (VMAT) treatment of lung tumors. METHODS:The authors have developed a method to identify the position of lung tumors during VMAT treatment, where the current ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4821545

    authors: Zhuang L,Liang J,Yan D,Zhang T,Marina O,Ionascu D

    更新日期:2013-10-01 00:00:00

  • A new data augmentation method based on local image warping for medical image segmentation.

    abstract:PURPOSE:The segmentation accuracy of medical images was improved by increasing the number of training samples using a local image warping technique. The performance of the proposed method was evaluated in the segmentation of breast masses, prostate and brain tumors, and lung nodules. METHODS:We propose a simple data a...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.14651

    authors: Liu H,Cao H,Song E,Ma G,Xu X,Jin R,Liu T,Liu L,Liu D,Hung CC

    更新日期:2020-12-10 00:00:00

  • A sparse representation-based radiomics for outcome prediction of higher grade gliomas.

    abstract:PURPOSE:Accurately predicting outcome (i.e., overall survival (OS) time) for higher grade glioma (HGG) has great clinical value and would provide optimized guidelines for treatment planning. Radiomics focuses on revealing underlying pathophysiological information in biomedical images for disease analysis and demonstrat...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.13288

    authors: Wu G,Shi Z,Chen Y,Wang Y,Yu J,Lv X,Chen L,Ju X,Chen Z

    更新日期:2019-01-01 00:00:00

  • Performance characterization of an integrated cone-beam CT system for dedicated gamma radiosurgery.

    abstract:PURPOSE:This work describes the performance characterization of a cone-beam CT-guided radiosurgery device, the Gamma Knife® Icon™. METHODS:The performance tests have been categorized into: (a) image quality and mechanical integrity; (b) image coregistration fidelity; (c) adaptive treatment delivery quality; (d) high d...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.13073

    authors: Sarfehnia A,Ruschin M,Chugh B,Yeboah C,Becker N,Cho YB,Lee Y

    更新日期:2018-06-29 00:00:00

  • Introducing gel dosimetry in a clinical environment: customization of polymer gel composition and magnetic resonance imaging parameters used for 3D dose verifications in radiosurgery and intensity modulated radiotherapy.

    abstract::Radiation sensitive gels have been used as dosimeters for clinical dose verification of different radiation therapy modalities. However, the use of gels is not widespread, because careful techniques are required to achieve the dose precision and accuracy aimed for in clinical dose verification. Here, the introduction ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.2712042

    authors: Crescenti RA,Scheib SG,Schneider U,Gianolini S

    更新日期:2007-04-01 00:00:00

  • Technical Note: Spot characteristic stability for proton pencil beam scanning.

    abstract:PURPOSE:The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil ...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4939663

    authors: Chen CC,Chang C,Moyers MF,Gao M,Mah D

    更新日期:2016-02-01 00:00:00

  • SU-E-T-453: Optimization of Dose Gradient for Gamma Knife Radiosurgery.

    abstract:PURPOSE:The goals of stereotactic radiosurgery (SRS) are the ablation of target tissue and sparing of critical normal tissue. We develop tools to aid in the selection of collimation and prescription (Rx) isodose line to optimize the dose gradient for single isocenter intracranial stereotactic radiosurgery (SRS) with Ga...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4735542

    authors: Sheth N,Chen Y,Yang J

    更新日期:2012-06-01 00:00:00

  • Measurement of absorbed dose-to-water for an HDR (192)Ir source with ionization chambers in a sandwich setup.

    abstract:PURPOSE:In this study, a dedicated device for ion chamber measurements of absorbed dose-to-water for a Nucletron microSelectron-v2 HDR (192)Ir brachytherapy source is presented. The device uses two ionization chambers in a so-called sandwich assembly. Using this setup and by taking the average reading of the two chambe...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4816673

    authors: Araki F,Kouno T,Ohno T,Kakei K,Yoshiyama F,Kawamura S

    更新日期:2013-09-01 00:00:00

  • Application of the convolution method for calculation of output factors for therapy photon beams.

    abstract::The output factor for a therapy photon beam is defined as the dose per monitor unit relative to the dose per monitor unit in a reference field. Convolution models for photon dose calculations yield the dose in units normalized to the incident energy fluence with phantom scatter intrinsically modeled. Output factors ca...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.596859

    authors: Ahnesjö A,Knöös T,Montelius A

    更新日期:1992-03-01 00:00:00

  • A nonvoxel-based dose convolution/superposition algorithm optimized for scalable GPU architectures.

    abstract:PURPOSE:Real-time adaptive planning and treatment has been infeasible due in part to its high computational complexity. There have been many recent efforts to utilize graphics processing units (GPUs) to accelerate the computational performance and dose accuracy in radiation therapy. Data structure and memory access pat...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4895822

    authors: Neylon J,Sheng K,Yu V,Chen Q,Low DA,Kupelian P,Santhanam A

    更新日期:2014-10-01 00:00:00

  • Normalized dose data for upper gastrointestinal tract contrast studies performed to infants.

    abstract::The aim of the current study was to (a) provide normalized dose data for the estimation of the radiation dose from upper gastrointestinal tract contrast (UGIC) studies carried out to infants and (b) estimate the average patient dose and risks associated with radiation from UGIC examinations performed in our institutio...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.2181297

    authors: Damilakis J,Stratakis J,Raissaki M,Perisinakis K,Kourbetis N,Gourtsoyiannis N

    更新日期:2006-04-01 00:00:00

  • Absolute diameter measurements of coronary arteries based on the first zero crossing of the Fourier spectrum.

    abstract::Current edge detection methods used to determine coronary artery dimensions from digital (DSA) images suffer a strong dependence on the system's modulation transfer function (MTF). The videodensitometric algorithms are less sensitive to MTF blurring, yet still result in an overestimation of the vessel size of 10% to 2...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.596370

    authors: Weber DM

    更新日期:1989-03-01 00:00:00

  • SU-E-T-398: Verification of Gamma Knife EXtend System Based Fractionated Treatment Planning Using EBT2 Film.

    abstract:PURPOSE:To present EBT2 film verification of treatment planning with the eXtend System, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery. METHODS:A human head shaped phantom simulated the verification process for fractionated Gamma Knife (GK) treatment. Phantom preparation for e...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1118/1.4735487

    authors: Gopishankar N,Bisht RK

    更新日期:2012-06-01 00:00:00

  • Motion estimation for cardiac functional analysis using two x-ray computed tomography scans.

    abstract:PURPOSE:This work concerns computed tomography (CT)-based cardiac functional analysis (CFA) with a reduced radiation dose. As CT-CFA requires images over the entire heartbeat, the scans are often performed at 10-20% of the tube current settings that are typically used for coronary CT angiography. A large image noise th...

    journal_title:Medical physics

    pub_type: 杂志文章

    doi:10.1002/mp.12425

    authors: Fung GSK,Ciuffo L,Ashikaga H,Taguchi K

    更新日期:2017-09-01 00:00:00