Abstract:
:The purpose of this study is to understand the effect of pitch on raw data interpolation in multislice spiral/helical computed tomography (CT) and provide guidelines for scanner design and protocol optimization. Multislice spiral CT is mainly characterized by the three parameters: the number of detector arrays, the detector collimation, and the table increment per x-ray source rotation. The pitch in multislice spiral CT is defined as the ratio of the table increment over the detector collimation in this study. In parallel to the current framework for studying longitudinal image resolution, the central fan-beam rays of direct and opposite directions are considered, assuming a narrow cone-beam angle. Generally speaking, sampling in the Radon domain by the direct and opposite central rays is nonuniform along the longitudinal axis. Using a recently developed methodology for quantifying the sensitivity of signal reconstruction from nonuniformly sampled finite points, the effect of pitch on raw data interpolation is analyzed in multislice spiral CT. Unlike single-slice spiral CT, in which image quality decreases monotonically as the pitch increases, the sensitivity of raw data interpolation in multislice spiral CT increases in an alternating way as the pitch increases, suggesting that image quality does not decrease monotonically in this case. The most favorable pitch can be found from the sensitivity-pitch plot for any given set of multislice spiral CT parameters. An example for four-slice spiral CT is provided. The study on the effect of pitch using the sensitivity analysis approach reveals the fundamental characteristics of raw data interpolation in multislice spiral CT, and gives insights into interaction between pitch and image quality. These results may be valuable for design of multislice spiral CT scanners and imaging protocol optimization in clinical applications.
journal_name
Med Physjournal_title
Medical physicsauthors
Wang G,Vannier MWdoi
10.1118/1.598804subject
Has Abstractpub_date
1999-12-01 00:00:00pages
2648-53issue
12eissn
0094-2405issn
2473-4209journal_volume
26pub_type
杂志文章相关文献
MEDICAL PHYSICS文献大全abstract:PURPOSE:Task Group 119 (TG-119) has been adopted for evaluating the adequacy of intensity-modulated radiation therapy (IMRT) commissioning and for establishing patient-specific IMRT quality assurance (QA) passing criteria in clinical practice. TG-119 establishes 95% confidence limits (CLs), which help clinics identify ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12759
更新日期:2018-03-01 00:00:00
abstract::Studies suggest that clinical outcomes are improved in repeat trigeminal neuralgia (TN) Gamma Knife radiosurgery if a different part of the nerve from the previous radiosurgery is treated. The MR images taken in the first and repeat radiosurgery need to be coregistered to map the first radiosurgery volume onto the sec...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1944287
更新日期:2005-07-01 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
pub_type: 杂志文章
doi:10.1118/1.4812678
更新日期:2013-08-01 00:00:00
abstract::Soft-tissue detectability in cone-beam computed tomography (CBCT) was evaluated via two-alternative forced-choice (2AFC) tests. Investigations included the dependence of detectability on radiation dose, the influence of the asymmetric three-dimensional (3D) noise-power spectrum (NPS) in axial and sagittal or coronal p...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2790586
更新日期:2007-11-01 00:00:00
abstract:PURPOSE:We have recently developed a dynamic tumor tracking irradiation system using Vero4DRT (MHI-Tm2 000). It is needed to create a 4D correlation model between a fiducial marker implanted near a tumor and an external surrogate as a function of time by continuously acquiring both fluoroscopy images and external surro...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734978
更新日期:2012-06-01 00:00:00
abstract::Angioplasty balloons inflated with a solution of the beta-emitter Re-188 have been used for intravascular brachytherapy to prevent restenosis. Coronary stents are in extensive clinical use for the treatment of de novo atherosclerotic stenoses. In this study, the effect of an interposed stent on the dose distribution h...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1533749
更新日期:2003-02-01 00:00:00
abstract:PURPOSE:To introduce video surface imaging guidance in synchronization with 4D cone-beam CT (CBCT) scans, and in combination with respiration- gated or target-tracked dose delivery to treat mobile tumors, without collaterally damaging nearby critical structures. METHODS:The approach uses the concept that the integral ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4734688
更新日期:2012-06-01 00:00:00
abstract:PURPOSE:State of the art to access radiofrequency (RF) heating near implants is computer modeling of the devices and solving Maxwell's equations for the specific setup. For a set of input parameters, a fixed result is obtained. This work presents a theoretical approach in the alternating current (ac) limit, which can p...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.3637495
更新日期:2011-10-01 00:00:00
abstract::The absorbed dose values determined with the Exradin and PTW-Markus plane-parallel chambers were compared to the values obtained with the ferrous sulphate dosimetry for a number of the Philips SL25 and the Therac 20 electron beams. For the plane-parallel chambers, the cavity-gas calibration factor Ngaspp, was derived ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597800
更新日期:1996-03-01 00:00:00
abstract::A tomographic attachment was designed and developed that attaches to our existing simulator. The film tomograms obtained with the aid of this device exhibit very low geometrical distortion and good contrast and resolution for the objects used in this investigation. In addition, our results to date show that adjacent a...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.594662
更新日期:1980-03-01 00:00:00
abstract:PURPOSE:To evaluate the treatment planning system (TPS) performance of the ZAP-X stereotactic radiosurgery (SRS) system through nondosimetric, dosimetric, and end-to-end (E2E) tests. METHODS:A comprehensive set of TPS commissioning and validation tests were developed using published guidelines. Nondosimetric validatio...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14740
更新日期:2021-01-28 00:00:00
abstract:PURPOSE:This work is to evaluate the effects of Compton current generation in three small-volume ionization chambers on measured beam characteristics for electron fields. METHODS:Beam scans were performed using Exradin A16, A26, and PTW 31014 microchambers. Scans with varying chamber components shielded were performed...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4929555
更新日期:2015-10-01 00:00:00
abstract::The modulation transfer function (MTF) of a screen-film system can be measured by two methods, i.e., a slit method with Fourier transform on the line spread function and a square-wave response function (SWRF) method. However, it is still uncertain whether MTFs obtained by the two methods are identical. In this study, ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.597456
更新日期:1995-02-01 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
pub_type: 杂志文章
doi:10.1118/1.1612947
更新日期:2003-10-01 00:00:00
abstract:PURPOSE:Image guidance is crucial for percutaneous tumor ablations, enabling accurate needle-like applicator placement into target tumors while avoiding tissues that are sensitive to injury and/or correcting needle deflection. Although ultrasound (US) is widely used for image guidance, magnetic resonance (MR) is prefer...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.13958
更新日期:2020-03-01 00:00:00
abstract:PURPOSE:Plastic scintillation detectors are used for dosimetry in small radiation fields with high dose gradients, e.g., provided by β-emitting sources like 106 Ru/106 Rh eye plaques. A drawback is a background signal caused by Cerenkov radiation generated by electrons passing the optical fibers (light guides) of this ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12374
更新日期:2017-09-01 00:00:00
abstract:PURPOSE:X-ray fluorescence computed tomography (XFCT) experiments have typically used pencil beams for data acquisition, which yielded good quality images of gold nanoparticles (AuNP) but prolonged the imaging time. Here we propose three novel collimator geometries for use with faster sheet beam XFCT data acquisition. ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12893
更新日期:2018-06-01 00:00:00
abstract::An indirect flat panel imager (FPI) with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low-dose and high resolution x-ray imaging. It is made by optically coupling a structured x-ray scintillator, e.g., thallium (Tl) doped cesium iodide (CsI), to an amorphous selenium (a-S...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2937652
更新日期:2008-07-01 00:00:00
abstract:PURPOSE:To implement the DMAIC (Define-Measure-Analyze-Improve-Control) can be used for customizing the patient-specific QA by designing site-specific range tolerances. METHODS:The DMAIC framework (process flow diagram, cause and effect, Pareto chart, control chart, and capability analysis) were utilized to determine ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.12721
更新日期:2018-02-01 00:00:00
abstract::Respiratory motion can produce misregistration errors between CT and PET images in cardiac PET/CT imaging. The objective of this study was to determine if manual registration of a single-phase end-expiration CT scan to the PET image would eliminate respiratory-induced artifacts. Listmode data from 71 cardiac PET patie...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.2965988
更新日期:2008-07-01 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
pub_type: 杂志文章
doi:10.1118/1.4813906
更新日期:2013-08-01 00:00:00
abstract::Some limitations of conventional two-dimensional computer programs used to plan radiation therapy are presented. These include: a lack of involvement in defining the clinical problem; deficiencies in the algorithms for computing dose; failure to compute dose throughout the volume of interest; an inability to handle tr...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.595226
更新日期:1982-07-01 00:00:00
abstract:PURPOSE:New technology has been developed to treat age-related macular degeneration (AMD) using 100 kVp pencil-beams that enter the patient through the radio-resistant sclera with a depth of interest between 1.6 and 2.6 cm. Measurement of reference and relative dose in a kilovoltage x-ray beam with a 0.42 cm diameter f...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4863482
更新日期:2014-02-01 00:00:00
abstract::Deformable image registration is an important tool for image-guided radiotherapy. Physics-model-based deformable image registration using finite element analysis is one of the methods currently being investigated. The calculation accuracy of finite element analysis is dependent on given boundary conditions, which are ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1774131
更新日期:2004-09-01 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
pub_type: 杂志文章
doi:10.1002/mp.13995
更新日期:2020-03-01 00:00:00
abstract:PURPOSE:The accuracy and precision of computed tomography (CT) pulmonary ventilation imaging with conventional CT scanners are limited by breathing variations. We propose a method to correct for the effect of breathing variations in CT ventilation imaging based on external respiratory signals acquired throughout a scan...
journal_title:Medical physics
pub_type: 临床试验,杂志文章
doi:10.1002/mp.12634
更新日期:2018-01-01 00:00:00
abstract:PURPOSE:Pulse pileup occurring at high x-ray fluxes can severely degrade the energy resolution provided by a photon counting detector, which can represent a problem in spectroscopic CT when performing quantitative material discrimination tasks. As the effects of pileup can be most easily seen as a degradation of a dete...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4820535
更新日期:2013-10-01 00:00:00
abstract:PURPOSE:The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. METHODS:MD Anderson Cancer Center Institutional Review Board appro...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.4906178
更新日期:2015-02-01 00:00:00
abstract::Cone-beam computed tomography systems have been developed to provide in situ imaging for the purpose of guiding radiation therapy. Clinical systems have been constructed using this approach, a clinical linear accelerator (Elekta Synergy RP) and an iso-centric C-arm. Geometric calibration involves the estimation of a s...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1118/1.1869652
更新日期:2005-04-01 00:00:00
abstract:OBJECTIVE:To develop an anthropomorphic, deformable and multimodal pelvis phantom with positron emission tomography extension for radiotherapy (ADAM PETer). METHODS:The design of ADAM PETer was based on our previous pelvis phantom (ADAM) and extended for compatibility with PET and use in 3T magnetic resonance imaging ...
journal_title:Medical physics
pub_type: 杂志文章
doi:10.1002/mp.14597
更新日期:2020-11-18 00:00:00