Gamma camera MTFs from edge response function measurements

Logan, K.W.; Hickey, Keith A.; Bull, S.R.

doi:10.1118/1.595283

Cited by 9 publications

(4 citation statements)

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“…Such measurements have been widely investigated in other areas of medical imaging. Examples of this work can be found in CT (12), planar γ-camera imaging (13), and MRI (14). Thomas et al (15) have reported a related approach involving a phantom with multiple compartments and computer segmentation of SPECT/CT images.…”

Section: Discussionmentioning

confidence: 99%

A Practical, Automated Quality Assurance Method for Measuring Spatial Resolution in PET

Lodge¹,

Rahmim²,

Wahl³

2009

J Nucl Med

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The use of different scanners, acquisition protocols, and reconstruction algorithms has been identified as a problem that limits the use of PET in multicenter trials. The aim of this project was to aid standardization of data collection by developing a quality assurance method for measuring the spatial resolution achieved with clinical imaging protocols. Methods A commercially available 68Ge cylinder phantom (diameter, 20 cm) with a uniform activity concentration was positioned in the center of the PET field of view, and an image was acquired using typical clinical parameters. Spatial resolution was measured by artificially generating an object function (O) with uniform activity within a 20-cm-diameter cylinder, assuming no noise and perfect spatial resolution, centered on the original image (I); dividing F[I] by F[O], where F indicates a 2-dimensional Fourier transform, to produce a modulation transfer function; and taking the inverse Fourier transform of the modulation transfer function to produce a point-spread function in image space. The method was validated using data acquired on 4 different commercial PET systems. Results Spatial resolution on the Discovery LS was measured at 5.75 ±0.58 mm, compared with 5.54 ±0.19 mm from separate point source measurements. Variability of the resolution measurements differed between scanners and protocols, but the typical SD was approximately 0.15 mm when iterative reconstruction was used. The potential for predicting resolution recovery coefficients for small objects was also demonstrated. Conclusion The proposed method does not require elaborate phantom preparation and is practical to perform, and data analysis is fully automated. This approach is useful for evaluating clinical reconstruction protocols across varying scanners and reconstruction algorithms and should greatly aid standardization of data collection between centers.

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Section: Discussionmentioning

confidence: 99%

A Practical, Automated Quality Assurance Method for Measuring Spatial Resolution in PET

Lodge¹,

Rahmim²,

Wahl³

2009

J Nucl Med

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“…The M T F in the x-scan line direction is determined from the Fourier transform of the line response function, the derivative of the ERF, according to Logan & Hickey (1983):…”

Section: Theory and Methods For M T F Estimationmentioning

confidence: 99%

Optical sectioning with a fluorescence confocal SLM: procedures for determination of the 2‐D digital modulation transfer function and for 3‐D reconstruction by tessellation

Schormann

Jovin

1990

Journal of Microscopy

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We have determined the operational parameters of a confocal scanning laser microscope (CSLM) used for fluorescence imaging. The system performance was characterized by the modulation transfer function (MTF), calculated from an edge response function (ERF) corresponding to a standard test pattern overlaying fluorescence solutions on a microscopic slide. Signal truncation error was avoided by making the ERF continuous at its limits through superposition of a suitable linear curve. We determined an appropriate scanning step density by defining a compromise between the requirements of the sampling theorem with respect to aliasing and the need for minimal suppression of higher spatial frequencies. These procedures for choosing the sampling density of the total digital CSLM permit a systematic optimization of the image acquisition parameters.A reproducible digital image was obtained, an important prerequisite for subsequent 3-D image reconstruction. The latter was accomplished by first developing and applying a maximally automated algorithm for finding closed and distinct contours (corresponding to objects in the 2-D optical sections). The missing information between contour loops was then interpolated by tessellation (triangulation) using a minimal polygon edge length criterion capable of describing closed surfaces even for adjacent contours with highly dissimilar geometries. In this procedure, we define an average shift length which compensates for the inherent disadvantage of run length encoding algorithms applied to different starting points in successive planes. The surface segments were used to calculate 3-D representations by applying a shading model, in the present applications specifically to chromosome I and the nucleolus of polytenized Chironomus thummi salivary gland nuclei.

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“…The use of modulation transfer function (MTF) in evaluating the spatial resolution of gamma camera systems was reported in previous studies [4][5][6][7][8]. The noise analysis of scintillation camera images for stochastic and non-stochastic effects was first reported by Grossman [9], and the normalized noise power spectrum (NNPS) of gamma camera system with some assumption for simplification was recently reported by Starck [8].…”

Section: Introductionmentioning

confidence: 96%

Performance evaluation for pinhole collimators of small gamma camera by MTF and NNPS analysis: Monte Carlo simulation study

Jeon

Kim

Kyung

et al. 2009

Nuclear Instruments and Methods in Physics Research Section A:

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Gamma camera MTFs from edge response function measurements

Cited by 9 publications

References 0 publications

A Practical, Automated Quality Assurance Method for Measuring Spatial Resolution in PET

A Practical, Automated Quality Assurance Method for Measuring Spatial Resolution in PET

Optical sectioning with a fluorescence confocal SLM: procedures for determination of the 2‐D digital modulation transfer function and for 3‐D reconstruction by tessellation

Performance evaluation for pinhole collimators of small gamma camera by MTF and NNPS analysis: Monte Carlo simulation study

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