Point Spread-Function, Line Spread-Function, and Modulation Transfer Function

Rossmann, Kurt

doi:10.1148/93.2.257

Cited by 241 publications

(197 citation statements)

References 8 publications

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“…The diameter of each bead is 0.18 mm, and beads are spaced vertically at 0.25 mm. The size of the bead is small enough that it essentially constitutes a Point Source for current DBT resolution (reconstructed slices) and as necessary, the size of the bead can be deconvolved from the bead data, as DBT resolution might improve 5. The illustration in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The same bead ramps provide a series of point sources (beads)5, 9, 10 These beads with their small diameter (18 mm) can be considered small enough to constitute “points” sources to determine the point spread function (PSF) and resulting MTF2, 5 for current levels of DBT resolution (typically 100 microns or better in DBT mode), particularly when one deconvolves the effective size of the small bead 11. It can be noted, that strictly speaking, the term MTF should be approached with caution for DBT, because the formal conditions for MTF are not met in systems that may be nonlinear and non‐Isoplanatic 5.…”

Section: Resultsmentioning

confidence: 99%

“…In particular, the study of the slice sensitivity profile by use of the angled bead ramps in the Tomophan vs. the stepped plates of the EUREF phantom, and the use of the small beads as Point Sources (for the Point Spread Function – PSF) as a method to determine the Modulation Transfer Function (MTF),5 as opposed to use of line sources in other (FDA poster) design.…”

Section: Introductionmentioning

confidence: 99%

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Design and development of a phantom for tomosynthesis with potential for automated analysis via the cloud

Goodenough

Levy

Ólafsdóttir

et al. 2018

J Applied Clin Med Phys

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This paper describes Development of a Phantom for Tomosynthesis with Potential for Automated Analysis via the Cloud. Several studies are underway to investigate the effectiveness of Tomosynthesis Mammographic Image Screening, including the large TMIST project as funded by the National Cancer Institute https://www.cancer.gov/about-cancer/treatment/clinical-trials/nci-supported/tmist. The development of the phantom described in this paper follows initiatives from the FDA, the AAPM TG245 task group, and European Reference Organization (EUREF) for Quality Assured Breast Screening and Diagnostic Services Committee report noting, that no formal endorsement nor recommendation for use has been sought, or granted by any of these groups. This paper reports on the possibility of using this newly developed Tomosynthesis Phantom for Quality Assurance, field testing of image performance, including remote monitoring of DBT system performance, e.g., via transmission over the cloud. The phantom includes tests for: phantom positioning and alignment (important for remote analysis), scan geometry (x and y), chest wall offset, scan slice width and Slice Sensitivity Profile (SSP(z)) slice geometry (slice width), scan slice incrementation (z), z axis geometry bead, low contrast detectability using low contrast spheres, spatial resolution via Point Spread Function (PSF), Image uniformity, Signal to Noise Ratio (SNR), and Contrast to Noise Ratio (CNR) via readings over an Aluminum square. The phantom is designed for use with automated analysis via transmission of images over the cloud and the analysis package includes test of positioning accuracy (roll, pitch, and yaw). Data are shown from several commercial Tomosynthesis Scanners including Fuji, GE, Hologic, IMS‐Giotti, and Siemens; however, the focus of this paper is on phantom design, and not in general aimed at direct commercial comparisons, and wherever possible the identity of the data is anonymized. Results of automated analysis of the phantom are shown, and it is demonstrated that reliable analysis of such a phantom can be achieved remotely, including transmission of data through the cloud.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and development of a phantom for tomosynthesis with potential for automated analysis via the cloud

Goodenough

Levy

Ólafsdóttir

et al. 2018

J Applied Clin Med Phys

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“…6(a) of the 2D resolution gauge vs. the 3D Wave Pattern gauge, and as mentioned in the previous theoretical section, the waveform profiles taken across an image of a tomographic slice may be mathematically analyzed to evaluate spatial performance of the imaging device. For example, a Fourier Transform (FT) is a decomposition of a signal into component frequencies, as utilized for instance in the previously mentioned Fourier Series of infinite square wave pattern, or for example when using a Modulation Transfer Function (MTF) (10) . In imaging systems, the mathematical properties of Eq.…”

Section: Results and Analysismentioning

confidence: 99%

“…As mentioned previously, the two major reasons are (i) the influence of finite z‐slice thickness and (ii) in‐plane (x‐y) point‐spread function (psf), or blur resolution limitations in the x‐y plane of the imaging device 10 , 11 …”

Section: Methodsmentioning

confidence: 99%

Method and phantom to study combined effects of in‐plane (x,y) and z‐axis resolution for 3D CT imaging

Goodenough

Levy²,

Kristinsson

et al. 2016

J Applied Clin Med Phys

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Increasingly, the advent of multislice CT scanners, volume CT scanners, and total body spiral acquisition modes has led to the use of Multi Planar Reconstruction and 3D datasets. In considering 3D resolution properties of a CT system it is important to note that both the in‐plane (x,y) and z‐axis (slice thickness) influence the visualization and detection of objects within the scanned volume. This study investigates ways to consider both the in‐plane resolution and the z‐axis resolution in a single phantom wherein analytic or visualized analysis can yield information on these combined effects. A new phantom called the “Wave Phantom” is developed that can be used to sample the 3D resolution properties of a CT image, including in–plane (x,y) and z‐axis information. The key development in this Wave Phantom is the incorporation of a z‐axis aspect of a more traditional step (bar) resolution gauge phantom. The phantom can be examined visually wherein a cutoff level may be seen; and/or the analytic analysis of the various characteristics of the waveform profile by including amplitude, frequency, and slope (rate of climb) of the peaks, can be extracted from the Wave Pattern using mathematical analysis such as the Fourier transform. The combined effect of changes in in‐plane resolution and z‐axis (thickness), are shown, as well as the effect of changes in either in‐plane resolution, or z‐axis thickness. Examples of visual images of the Wave pattern as well as the analytic characteristics of the various harmonics of a periodic Wave pattern resulting from changes in resolution filter and/or slice thickness, and position in the field of view are shown. The Wave Phantom offers a promising way to investigate 3D resolution results from combined effect of in‐plane (x‐y) and z‐axis resolution as contrasted to the use of simple 2D resolution gauges that need to be used with separate measures of z‐axis dependency, such as angled ramps. It offers both a visual pattern as well as a pattern amenable to analytic analysis using Fourier Transform methods, and is believed to offer an image quality test closer to the diagnostic task where the 2D image has the hidden third (z) axis effects.PACS number(s): 87.57.Q‐

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