The fan-beam gamma camera

Keyes, W. I.

doi:10.1088/0031-9155/20/3/013

Cited by 29 publications

(7 citation statements)

References 4 publications

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“…A similar design has been published by Entine (Entine et al 1979) about 20 years ago, combining a CdTe detector with a parallel plate collimator. Before this, the design of a linear detector has been proposed independently by Keyes (Keyes 1975) and Tosswill (Tosswill 1977). Traditional rectangular SPECT detectors have been studied in combination with rotating slat collimators by Webb, who found an increased sensitivity of about a factor of 40 for the rotating slat concept (Webb et al 1992).…”

Section: Introductionmentioning

confidence: 99%

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

2011

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Abstract. Parallel and converging hole collimators are most frequently used in nuclear medicine. Less common is the use of rotating slat collimators for Single Photon Emission Computed Tomography (SPECT). The higher photon collection efficiency, inherent to the geometry of rotating slat collimators results in much lower noise in the data. However, plane integrals contain spatial information in only one direction, whereas line integrals provide two-dimensional information. It is not a trivial question whether the initial gain in efficiency will compensate for the lower information content in the plane integrals. Therefore, a comparison of the performance of parallel hole and rotating slat collimation is needed. This study compares SPECT with rotating slat and parallel hole collimation in combination with MLEM reconstruction with accurate system modeling and correction for scatter and attenuation. A contrast-to-noise study revealed an improvement of a factor 2 to 3 for hot lesions and more than a factor of 4 for cold lesion. Furthermore, a clinically relevant case of heart lesion detection is simulated for rotating slat and parallel hole collimators. In this case, rotating slat collimators outperform the traditional parallel hole collimators. We conclude that rotating slat collimators are a valuable alternative for parallel hole collimators.

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Section: Introductionmentioning

confidence: 99%

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

2011

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“…Converging collimation was first proposed in 1968 for thyroid imaging [1]; interest for pediatric, renal and cardiac studies followed soon [2]- [6]. Over the years various types of collimators have been proposed, such as slant-hole collimators [7] or the rotating slat collimator [8]- [10]; some were proposed specifically for cardiac imaging, e.g. the seven-pinhole collimator [11], [12].…”

Section: Introductionmentioning

confidence: 99%

High efficiency high Resolution SPECT tecniques for cardiac imaging

Accorsi¹

2008

Proceedings of Frontiers in Imaging Science: High Performance Nuclear Medicine Imagers for Vascular Disease Imaging (Brain and

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Current standard clinical SPECT techniques provide a resolution of at best 1 cm and sensitivity in the order of 10-4. Performance is largely determined by the collimator. Basic geometry couples resolution and sensitivity; the problem of high-resolution imaging is a formidable one because, to image at constant Signal-to-Noise, resolution improvements must be supported by simultaneous sensitivity improvements that scale with the fourth power of resolution. However, current standard systems are designed to also accommodate whole body studies and, thus, routinely provide large-area detectors. Single-organ imaging does not need the same field of view, which, then, can be better utilized with collimation schemes that magnify or cast more copies (i.e. acquire several views) simultaneously on the detector. As demonstrated by the recent experience of small animal imaging, these collimation techniques can be readily coupled to existing detectors to offer better performance than standard parallel-hole collimation. Similar approaches have been explored for a number of years for cardiac imaging. The same ideas also apply to other single-organ studies (e.g. brain and breast) as well as to pediatric imaging.

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“…A similar design was published by Entine (1979) about 20 years ago combining a CdTe detector with a parallel plate collimator. Before this the design of a linear detector was proposed independently by Keyes (1975) and Tosswill (1977).…”

Section: Introductionmentioning

confidence: 99%

System characteristics of SPECT with a slat collimated strip detector

et al. 2006

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In classical SPECT with parallel hole collimation, the sensitivity is constant over the field of view (FOV). This is no longer the case if a rotating slat collimator with planar photon collection is used: there will be a significant variation of the sensitivity within the FOV. Since not compensating for this inhomogeneous sensitivity distribution would result in non-quantitative images, an accurate knowledge of the sensitivity is mandatory to account for it during reconstruction. On the other hand, the spatial resolution versus distance dependency remains unaltered compared to parallel hole collimation. For deriving the sensitivity, different factors have to be taken into account: a first factor concerns the intrinsic detector properties and will be incorporated into the calculations as a detection efficiency term depending on the incident angle. The calculations are based on a second and more pronounced factor: the collimator and detector geometry. Several assumptions will be made for the calculation of the sensitivity formulae and it will be proven that these calculations deliver a valid prediction of the sensitivity at points far enough from the collimator. To derive a close field model which also accounts for points close to the collimator surface, a modified calculation method is used. After calculating the sensitivity in one plane it is easy to obtain the tomographic sensitivity. This is done by rotating the sensitivity maps for spin and camera rotation. The results derived from the calculations are then compared to simulation results and both show good agreement after including the aforementioned detection efficiency term. The validity of the calculations is also proven by measuring the sensitivity in the FOV of a prototype rotating slat gamma camera. An expression for the resolution of these planar collimation systems is obtained. It is shown that for equal collimator dimensions the same resolution-distance relationship is obtained as for parallel hole collimators. Although, a better spatial resolution can be obtained with our prototype camera due to the smaller pitch of the slats. This can be achieved without a major drop in system sensitivity due to the fact that the slats consist of less collimator material compared to a parallel hole collimator. The accuracy of the calculated resolution is proven by comparison with Monte Carlo simulation and measurement resolution values.

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The fan-beam gamma camera

Cited by 29 publications

References 4 publications

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

Tomographic image quality of rotating slat versus parallel hole-collimated SPECT

High efficiency high Resolution SPECT tecniques for cardiac imaging

System characteristics of SPECT with a slat collimated strip detector

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