Abstract:
PURPOSE:Cone beam computed tomography (CBCT) suffers from a large amount of scatter, resulting in severe scatter artifacts in the reconstructions. Recently, a new scatter correction approach, called improved primary modulator scatter estimation (iPMSE), was introduced. That approach utilizes a primary modulator that is inserted between the X-ray source and the object. This modulation enables estimation of the scatter in the projection domain by optimizing an objective function with respect to the scatter estimate. Up to now the approach has not been implemented on a clinical angiography C-arm CT system. METHODS:In our work, the iPMSE method is transferred to a clinical C-arm CBCT. Additional processing steps are added in order to compensate for the C-arm scanner motion and the automatic X-ray tube current modulation. These challenges were overcome by establishing a reference modulator database and a block-matching algorithm. Experiments with phantom and experimental in vivo data were performed to evaluate the method. RESULTS:We show that scatter correction using primary modulation is possible on a clinical C-arm CBCT. Scatter artifacts in the reconstructions are reduced with the newly extended method. Compared to a scan with a narrow collimation, our approach showed superior results with an improvement of the contrast and the contrast-to-noise ratio for the phantom experiments. In vivo data are evaluated by comparing the results with a scan with a narrow collimation and with a constant scatter correction approach. CONCLUSIONS:Scatter correction using primary modulation is possible on a clinical CBCT by compensating for the scanner motion and the tube current modulation. Scatter artifacts could be reduced in the reconstructions of phantom scans and in experimental in vivo data.
journal_name
Med Physjournal_title
Medical physicsauthors
Bier B,Berger M,Maier A,Kachelrieß M,Ritschl L,Müller K,Choi JH,Fahrig Rdoi
10.1002/mp.12094subject
Has Abstractpub_date
2017-09-01 00:00:00pages
e125-e137issue
9eissn
0094-2405issn
2473-4209journal_volume
44pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract::The use of electronic portal imaging devices (EPIDs) is a promising method for the dosimetric verification of external beam, megavoltage radiation therapy-both pretreatment and in vivo. In this study, a previously developed EPID back-projection algorithm was modified for IMRT techniques and applied to an amorphous sil...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2147744
更新日期:2006-02-01 00:00:00
abstract::Cardiac arrhythmias are a major health burden, associated with reduced quality of life and substantial morbidity and mortality. Current therapy includes moderately effective medication and catheter-based ablation of arrhythmogenic substrates in the heart. Catheter interventions frequently have to be repeated due to re...
journal_title:Medical physics
pub_type: 杂志文章,评审
doi:10.1002/mp.12595
更新日期:2018-11-01 00:00:00
abstract::The dissemination of scientific advances has changed little since the first peer-reviewed journal was published in 1665 - that is, until this past decade. The print journal, delivered by mail and stored on office shelves and in library reading rooms around the world, has been transformed by immediate, on-demand access...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4736173
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:To develop an automated technique for evaluating lung stereotactic body radiotherapy (SBRT) plan quality and predicting achievable lung dose constraints. METHODS:We examined the workflow scripting capabilities of a radiation oncology software package (MIM Software Inc) for automatically generating mean dose gr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735279
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:To investigate whether functionally-weighted dose-volume histogram (DVH) parameters are more predictive of radiation-induced pneumonitis (RP) than standard parameters such as V20 and mean lung dose (MLD). MATERIALS AND METHODS:A retrospective chart review identified 26 patients who received curative-intent rad...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4740190
更新日期:2012-07-01 00:00:00
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
更新日期:2006-08-01 00:00:00
abstract::In a recent paper of Miller et al. (Med. Phys. 43(5), 2141-2152 (2016), the voltage dependence polarity effect of microionization chambers was studied. It was identified that polarity effect arises from the difference in electric potential between the collecting electrode and the guard electrode, which in turn deforms...
journal_title:Medical physics
pub_type: 信件
doi:10.1002/mp.12019
更新日期:2017-03-01 00:00:00
abstract::In external beam radiotherapy, electronic portal imaging becomes more and more an indispensable tool for the verification of the patient setup. For the safe clinical introduction of high dose conformal radiotherapy like intensity modulated radiation therapy, on-line patient setup verification is a prerequisite to ensu...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1668391
更新日期:2004-04-01 00:00:00
abstract::The geometric accuracy and precision of an image-guided treatment system were assessed. Image guidance is performed using an x-ray volume imaging (XVI) system integrated with a linear accelerator and treatment planning system. Using an amorphous silicon detector and x-ray tube, volumetric computed tomography images ar...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2143141
更新日期:2006-01-01 00:00:00
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
更新日期:1999-11-01 00:00:00
abstract:PURPOSE:To develop a pencil beam dose calculation algorithm for scanned proton beams that improves modeling of scatter events. METHODS:Our pencil beam algorithm (PBA) was developed for calculating dose from monoenergetic, parallel proton beams in homogeneous media. Fermi-Eyges theory was implemented for pencil beam tr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735624
更新日期:2012-06-01 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
pub_type: 杂志文章
doi:10.1118/1.3002412
更新日期:2008-12-01 00:00:00
abstract::A Monte Carlo computer study of the total dose distribution from neutrons and prompt gamma emissions (but excluding the contribution from conversion and Auger electrons) for gadolinium neutron capture therapy of brain tumors has been carried out in order to test the theoretic feasibility of this modality using commerc...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.596761
更新日期:1992-09-01 00:00:00
abstract::A simple modification is presented for two commercially available hyperthermia applicators which dramatically improves the regulation and dynamic control of the temperature at the bolus/tissue interface. This alteration requires the addition of a variable speed pump, bubble trap, simple heat exchanger, and a few minor...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597196
更新日期:1994-09-01 00:00:00
abstract::Respiratory motion can introduce significant errors in radiotherapy. Conventional CT scans as commonly used for treatment planning can include severe motion artifacts that result from interplay effects between the advancing scan plane and object motion. To explicitly include organ/target motion in treatment planning a...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1869852
更新日期:2005-04-01 00:00:00
abstract::The American Association of Physicists in Medicine recommends that the reference dose-rate distribution, used for treatment planning for low-energy photon brachytherapy sources in routine clinical use, must be based on at least two independent determinations: one using experimentally measured dose rates and one using ...
journal_title:Medical physics
pub_type: 指南,杂志文章
doi:10.1118/1.1690712
更新日期:2004-05-01 00:00:00
abstract:PURPOSE:Partial scan reconstruction (PSR) artifacts are present in myocardial perfusion imaging using dynamic multidetector computed tomography (MDCT). PSR artifacts appear as temporal CT number variations due to inconsistencies in the angular data range used to reconstruct images and compromise the quantitative value ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3665767
更新日期:2012-01-01 00:00:00
abstract::A method is proposed for realistic simulation of the breast ductal network as part of a computer three-dimensional (3-D) breast phantom. The ductal network is simulated using tree models. Synthetic trees are generated based upon a description of ductal branching by ramification matrices (R matrices), whose elements re...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1586453
更新日期:2003-07-01 00:00:00
abstract:PURPOSE:To validate GPUMCD, a new package for fast Monte Carlo dose calculations based on the GPU (graphics processing unit), as a tool for low-energy single seed brachytherapy dosimetry for specific seed models. As the currently accepted method of dose calculation in low-energy brachytherapy computations relies on sev...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3598441
更新日期:2011-07-01 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
pub_type: 杂志文章
doi:10.1118/1.4937780
更新日期:2016-01-01 00:00:00
abstract:BACKGROUND:X-ray dark-field radiography could enhance mammography by providing more information on imaged tissue and microcalcifications. The dark field signal is a measure of small angle scattering and can thus provide additional information on the imaged materials. This information can be useful for material distinct...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14043
更新日期:2020-04-01 00:00:00
abstract::Based on direction from AAM Board of Directors, JMPLSC has redefined its scope and name. On November 4, 2011 the subcommittee renamed itself the Medical Physics Licensure and Regulatory Recognition Subcommittee. Its newly defined charge is to promote the protection of the public through the recognition of the professi...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735947
更新日期:2012-06-01 00:00:00
abstract::Current generation electronic portal imaging devices (EPID) contain a 1.0 mm copper conversion plate to increase detection efficiency of a therapeutic megavoltage spectrum. When using these EPIDs for low-Z target imaging, the conversion plate largely attenuates the large populations of diagnostic energy photons, there...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4740105
更新日期:2012-07-01 00:00:00
abstract:PURPOSE:Transrectal ultrasound (TRUS)-guided needle biopsy is the current gold standard for prostate cancer diagnosis. However, up to 40% of prostate cancer lesions appears isoechoic on TRUS. Hence, TRUS-guided biopsy has a high false negative rate for prostate cancer diagnosis. Magnetic resonance imaging (MRI) is bett...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4905104
更新日期:2015-03-01 00:00:00
abstract::The calibration (in rad/nC) of an air-filled tissue-equivalent ionization chamber for neutrons of 15-MeV average energy was determined by measuring absolute fluences and calculating the kerma per unit fluence. The neutron calibration determined from the gamma-ray calibration and application of the Bragg-Gray relation ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594310
更新日期:1977-03-01 00:00:00
abstract::Inherent in the line-spread function approach in modulation transfer function (MTF) determinations is the use of a microdensitometer to scan the density pattern resulting from the line exposure. In such a procedure, loss of fidelity in the distribution being scanned is expected. This loss is due in part to the use of ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594187
更新日期:1975-09-01 00:00:00
abstract::Computer algorithms for rotational therapy beams, in most cases, perform dose calculations by summing stored fixed beam data at finite angular steps. Such an algorithm, based on the Bentley beam model, was evaluated by comparing calculations with measured data for an 18-MV x-ray beam. Measurements were made in a speci...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595985
更新日期:1987-11-01 00:00:00
abstract::Because of complex dose distributions and dose gradients that are created in three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), photon- and electron-energy spectra might change significantly with spatial locations and doses. This study examined variations in photon- and...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2710550
更新日期:2007-04-01 00:00:00
abstract:PURPOSE:To reduce image noise and radiation dose in Digital Breast Tomosynthesis (DBT) reconstructions. METHODS:A retrospective study was performed on clinical data sets acquired at a normal dose with Hologic Selenia Dimensions DBT systems. The Prior Image Constrained Compressed Sensing (PICCS) algorithm was used to r...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4735982
更新日期:2012-06-01 00:00:00
abstract::We have developed an analytic solution for spatially resolved diffuse reflectance within the deltaP1 approximation to the radiative transport equation for a semi-infinite homogeneous turbid medium. We evaluate the performance of this solution by comparing its predictions with those provided by Monte Carlo simulations ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2828184
更新日期:2008-02-01 00:00:00