System characteristics of SPECT with a slat collimated strip detector

Vandenberghe, Stefaan; Holen, Roel Van; Staelens, Steven; Lemahieu, Ignace

doi:10.1088/0031-9155/51/2/014

Cited by 16 publications

(10 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…23 But in practice, these factors can affect the statistical nature of the projection data as well as the noise propagation in the reconstruction, and should be evaluated in future work. First, the sensitivity of the rotating slat system decreases as the object-to-detector distance increases, 24 while the sensitivity of the parallel-hole system remains constant in the FOV. The rotating-slat system exhibits a 1 / r sensitivity dependence ͑where r is the object-to-detector distance͒ resulting in better performance as the object is put closer to the detector.…”

Section: Discussionmentioning

confidence: 99%

Study of noise propagation and the effects of insufficient numbers of projection angles and detector samplings for iterative reconstruction using planar-integral data

Zhang

Zeng

2006

Med. Phys.

View full text Add to dashboard Cite

A rotating slat collimator can be used to acquire planar-integral data. It achieves higher geometric efficiency than a parallel-hole collimator by accepting more photons, but the planar-integral data contain less tomographic information that may result in larger noise amplification in the reconstruction. Lodge evaluated the rotating slat system and the parallel-hole system based on noise behavior for an FBP reconstruction. Here, we evaluate the noise propagation properties of the two collimation systems for iterative reconstruction. We extend Huesman's noise propagation analysis of the line-integral system to the planar-integral case, and show that approximately 2.0(D/dp) SPECT angles, 2.5(D/dp) self-spinning angles at each detector position, and a 0.5dp detector sampling interval are required in order for the planar-integral data to be efficiently utilized. Here, D is the diameter of the object and dp is the linear dimension of the voxels that subdivide the object. The noise propagation behaviors of the two systems are then compared based on a least-square reconstruction using the ratio of the SNR in the image reconstructed using a planar-integral system to that reconstructed using a line-integral system. The ratio is found to be proportional to the square root of F/D, where F is a geometric efficiency factor. This result has been verified by computer simulations. It confirms that for an iterative reconstruction, the noise tradeoff of the two systems is not only dependent on the increase of the geometric efficiency afforded by the planar projection method, but also dependent on the size of the object. The planar-integral system works better for small objects, while the line-integral system performs better for large ones. This result is consistent with Lodge's results based on the FBP method.

show abstract

Section: Discussionmentioning

confidence: 99%

Study of noise propagation and the effects of insufficient numbers of projection angles and detector samplings for iterative reconstruction using planar-integral data

Zhang

Zeng

2006

Med. Phys.

View full text Add to dashboard Cite

show abstract

“…For the RS collimator, the geometric efficiency E r is shiftvariant. The geometric efficiency of a small detector element dl at location l along the slat for a point source located at (α, γ) in the plane defined by two adjacent slat septa is [4]…”

Section: B Geometric Efficiencymentioning

confidence: 99%

Comparison Between Parallel Hole and Rotating Slat Collimation: Analytical Noise Propagation Models

Zhou

Defrise

Vunckx

2010

IEEE Trans. Med. Imaging

View full text Add to dashboard Cite

We have previously proposed a method to compare tomographic systems. It is assumed that each system acquires a tomographic scan of a certain tracer distribution in the same acquisition time. From this scan, each system is forced to reconstruct an image with a predefined spatial resolution. The system that can perform this task with the "most favorable" noise propagation is considered as the best system. The variance on pixel values or region-of-interest (ROI) values is used to assess the noise in the reconstructed image. In this paper, we extend this idea to compare the performance of parallel hole (PH) and rotating slat (RS) collimations. Two different analytical approaches were used to analyze the variance of the reconstructed pixel/ROI values. The first method is based on the filtered-backprojection (FBP) theory, and was applied to the central point of a uniform symmetrical phantom. It yields analytical expressions for the optimal collimator aperture and the corresponding variance of the reconstructed pixel values, but it can only be applied to highly symmetrical configurations. The second method is based on approximations for the Fisher information matrix. It provides numerical results, and it is more general and can be applied to nonsymmetrical objects and shift-variant tomographic systems. The collimations were compared for both planar imaging and volume imaging. The main results are as follows. 1) For cases where both methods are valid, they are in excellent agreement. 2a) The optimal collimator aperture varies linearly with the target resolution. 2b) For a fixed target resolution, the optimal collimator aperture depends on the collimator type and the imaging mode (planar or volume). 2c) The optimal aperture of PH is a factor of √2 larger than that of RS. 3a) The relative performance of the two collimators is determined by both the object size and the object-to-detector distance. 3b) Pixel variance and variances of ROIs with varying sizes yield very similar relative performance for RS versus PH.

show abstract

“…69 Its system characteristics have been described in Ref. 70. Because the collimation is in only one direction, the sensitivity is much higher than that of a parallelhole collimator.…”

Section: A4 Other Types Of Collimationmentioning

confidence: 99%

Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging

et al. 2015

Self Cite

View full text Add to dashboard Cite

In single photon emission computed tomography, the choice of the collimator has a major impact on the sensitivity and resolution of the system. Traditional parallel-hole and fan-beam collimators used in clinical practice, for example, have a relatively poor sensitivity and subcentimeter spatial resolution, while in small-animal imaging, pinhole collimators are used to obtain submillimeter resolution and multiple pinholes are often combined to increase sensitivity. This paper reviews methods for production, sensitivity maximization, and task-based optimization of collimation for both clinical and preclinical imaging applications. New opportunities for improved collimation are now arising primarily because of (i) new collimator-production techniques and (ii) detectors with improved intrinsic spatial resolution that have recently become available. These new technologies are expected to impact the design of collimators in the future. The authors also discuss concepts like septal penetration, high-resolution applications, multiplexing, sampling completeness, and adaptive systems, and the authors conclude with an example of an optimization study for a parallel-hole, fan-beam, cone-beam, and multiple-pinhole collimator for different applications.

show abstract

System characteristics of SPECT with a slat collimated strip detector

Cited by 16 publications

References 16 publications

Study of noise propagation and the effects of insufficient numbers of projection angles and detector samplings for iterative reconstruction using planar-integral data

Study of noise propagation and the effects of insufficient numbers of projection angles and detector samplings for iterative reconstruction using planar-integral data

Comparison Between Parallel Hole and Rotating Slat Collimation: Analytical Noise Propagation Models

Review of SPECT collimator selection, optimization, and fabrication for clinical and preclinical imaging

Contact Info

Product

Resources

About