The experimental evaluation of a prototype rotating slat collimator for planar gamma camera imaging

Martin Lodge, D. M. Binnie, M. A. Flower, S. Webb

Research output: Contribution to journalArticle

Abstract

A collimator consisting of a series of parallel slats has been constructed and used in conjunction with a conventional gamma camera to collect one-dimensional projections of the radioisotope distribution being imaged. With the camera remaining stationary, the collimator was made to rotate continuously over the face of the detector and the projections acquired were used to reconstruct a planar image by the theory of computed tomography. The propagation of noise on image reconstruction was largely offset by the increased geometric efficiency that resulted from the enlarged solid angle of acceptance afforded by the slat collimator. For a uniform disc of activity the signal to noise ratio (SNR) at a point in an image reconstructed by convolution and backprojection is shown to be given by SNR=(total events detected)1/2 / beta (number of pixels)3/4 where beta = square root 2 pi -1/2 integral - infinity+ infinity mod Q1( xi ) mod 2d xi and Q1( xi ) is the one-dimensional filter function in Fourier space. Improved noise behaviour was observed for images acquired with the slat collimator compared to those acquired with a low-energy high-resolution (LEHR) collimator for small distributions of activity. Spatial resolution with the slat collimator was approximately equal to that obtained with an LEHR collimator and improved contrast was observed in images of small hot regions.

Original languageEnglish (US)
Article number007
Pages (from-to)427-448
Number of pages22
JournalPhysics in Medicine and Biology
Volume40
Issue number3
DOIs
StatePublished - 1995
Externally publishedYes

Fingerprint

Signal-To-Noise Ratio
collimators
Radionuclide Imaging
Noise
Signal to noise ratio
Cameras
cameras
prototypes
Imaging techniques
Gamma Cameras
Computer-Assisted Image Processing
evaluation
Image reconstruction
Convolution
Radioisotopes
Tomography
Pixels
Detectors
infinity
signal to noise ratios

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Physics and Astronomy (miscellaneous)
  • Biomedical Engineering

Cite this

The experimental evaluation of a prototype rotating slat collimator for planar gamma camera imaging. / Lodge, Martin; Binnie, D. M.; Flower, M. A.; Webb, S.

In: Physics in Medicine and Biology, Vol. 40, No. 3, 007, 1995, p. 427-448.

Research output: Contribution to journalArticle

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