Collimator design for single photon emission tomography

Moore, Stephen; Kouris, Kypros; Cullum, Ian

doi:10.1007/bf00184130

Cited by 83 publications

(44 citation statements)

References 43 publications

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“…All the aforementioned types of collimation however suffer from the same trade-off between sensitivity, spatial resolution and FOV. For a discussion on the most common SPECT collimators with respect to these three criteria, the reader is referred to the excellent overview papers by Wieczorek (Wieczorek and Goedicke 2006), Accorsi (Accorsi 2006) and Moore (Moore et al 1992). Rotating slat (RS) collimators (figure 1), which are the subject of this paper, break with the traditional collimators described above.…”

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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“…In a parallel-hole collimator system, the efficiency ε -hole and resolution R-hole of the collimator were defined as follows [2,8]:…”

Section: Pinhole and Three Parallel-hole Collimatorsmentioning

confidence: 99%

“…In SPECT, the collimator is an essential component of the system, because the imaging performance (including sensitivity and spatial resolution) depends mainly on the collimator [8]. Collimators types are generally classified as parallel-hole, pinhole, converging, and diverging.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study of Different Types of Collimators for a High-Resolution Preclinical CdTe Pixelated Semiconductor SPECT System

Jeong

Kim

Bae

et al. 2016

Journal of the Optical Society of Korea

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In single-photon-emission computed tomography (SPECT) with a pixelated semiconductor detector (PSD), not only pinhole collimators but also parallel-hole collimators are often used in preclinical nuclear-medicine imaging systems. The purpose of this study was to evaluate and compare pinhole and parallel-hole collimators in a PSD. For that purpose, we paired a PID 350 (Ajat Oy Ltd., Finland) CdTe PSD with each of the four collimators most frequently used in preclinical nuclear medicine: (1) a pinhole collimator, and (2) low-energy high-resolution (LEHR), (3) low-energy general-purpose (LEGP), and (4) low-energy high-sensitivity (LEHS) parallel-hole collimators. The sensitivity and spatial resolution of each collimator was evaluated using a point source and a hot-rod phantom. The highest sensitivity was achieved using LEHS, followed by LEGP, LEHR, and pinhole. Also, at a source-to-collimator distance of 2 cm, the spatial resolution was 1.63, 2.05, 2.79, and 3.45 mm using pinhole, LEHR, LEGP, and LEHS, respectively. The reconstructed hot-rod phantom images showed that the pinhole collimator and the LEHR parallel-hole collimator give a fine spatial resolution for preclinical SPECT with PSD. In conclusion, we successfully compared different types of collimators for a preclinical pixelated semiconductor SPECT system.

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“…In this case, the collection efficiency is minimal due to the fact that the system sensitivity and system spatial resolution operate as opposing magnitudes. 2,[6][7][8] The spatial resolution also depends on the source-collimator distance. As this distance increases, the spatial resolution severely worsens.…”

Section: Introductionmentioning

confidence: 99%

Stereoscopic full aperture imaging in nuclear medicine

Strocovsky

Otero

2011

AIP Advances

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Images of planar scintigraphy and single photon emission computerized tomography (SPECT) used in nuclear medicine are often low quality. They usually appear to be blurred and noisy. This problem is due to the low spatial resolution and poor sensitivity of the acquisition technique with the gamma camera (GC). Other techniques, such as coded aperture imaging (CAI) reach higher spatial resolutions than GC. However, CAI is not frequently used for imaging in nuclear medicine, due to the decoding complexity of some images and the difficulty in controlling the noise magnitude. Summing up, the images obtained through GC are low quality and it is still difficult to implement CAI technique. A novel technique, full aperture Imaging (FAI), also uses gamma ray-encoding to obtain images, but the coding system and the method of images reconstruction are simpler than those used in CAI. In addition, FAI also reaches higher spatial resolution than GC. In this work, the principles of FAI technique and the method of images reconstruction are explained in detail. The FAI technique is tested by means of Monte Carlo simulations with filiform and spherical sources. Spatial resolution tests of GC versus FAI were performed using two different sourcedetector distances. First, simulations were made without interposing any material between the sources and the detector. Then, other more realistic simulations were made. In these, the sources were placed in the centre of a rectangular prismatic region, filled with water. A rigorous comparison was made between GC and FAI images of the linear filiform sources, by means of two methods: mean fluence profile graphs and correlation tests. Finally, three-dimensional capacity of FAI was tested with two spherical sources. The results show that FAI technique has greater sensitivity (>100 times) and greater spatial resolution (>2.6 times) than that of GC with LEHR collimator, in both cases, with and without attenuating material and long and shortdistance configurations. The FAI decoding algorithm reconstructs simultaneously four different projections which are located in separate image fields on the detector plane, while GC produces only one projection per acquisition. Simulations have allowed comparison of both techniques under ideal identical conditions. Our results show it is possible to apply an extremely simple encoded imaging technique, and get three-dimensional radioactivity information for simplistic geometry sources. The results are promising enough to evaluate the possibility of future research with more complex sources typical of nuclear medicine imaging.

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Collimator design for single photon emission tomography

Cited by 83 publications

References 43 publications

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

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

A Numerical Study of Different Types of Collimators for a High-Resolution Preclinical CdTe Pixelated Semiconductor SPECT System

Stereoscopic full aperture imaging in nuclear medicine

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