An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes
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Date
2011-12-07
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IOP Publishing Ltd
Abstract
Multiple pinholes are advantageous for maximizing the use of the available
field of view (FOV) of compact small animal single photon emission computed
tomography (SPECT) detectors. However, when the pinholes are aligned
axially to optimize imaging of extended objects, such as rodents, multiplexing
of the pinhole projections can give rise to inconsistent datawhich leads to ‘ghost
point’ artefacts in the reconstructed volume. A novel four pinhole collimator
with a baffle was designed and implemented to eliminate these inconsistent
projections. Simulation and physical phantom studies were performed to
investigate artefacts from axially aligned pinholes and the efficacy of the
baffle in removing inconsistent data and, thus, reducing reconstruction artefacts.
SPECT was performed using a Defrise phantom to investigate the impact of
collimator design on FOV utilization and axial blurring effects. Multiple
pinhole SPECT acquired with a baffle had fewer artefacts and improved
quantitative accuracy when compared to SPECT acquired without a baffle.
The use of four pinholes positioned in a square maximized the available
FOV, increased acquisition sensitivity and reduced axial blurring effects.
These findings support the use of a baffle to eliminate inconsistent projection
data arising from axially aligned pinholes and improve small animal SPECT
reconstructions. © 2011 IOP Publishing LTD
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Keywords
Phantoms, Single photon emission computed tomography, Animals, Rats, Data, Collimators
Citation
Kench, P. L., Lin, J., Grégoire, M. C., & Meikle, S. R. (2011). An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes. Physics in Medicine and Biology, 56(23), 7487-7503. doi:10.1088/0031-9155/56/23/010