SPECT scatter correction in non-homogeneous media

Meikle, Steven R.; Hutton, BF; Bailey, Dale L.; Fulton, Roger; Schindhelm, Klaus

doi:10.1007/bfb0033740

Cited by 24 publications

(16 citation statements)

References 3 publications

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“…It has been s hown, though, that the best value for k depends on the energy of the emitted photons, the object geometry, the widt h and location of the scatter energy window, and the type of attenuating material [43, Some effort has also b e n made to correct for the difference in the spatial distribut ions of the scatter and photopeak window data. The approach taken by Meikle et al [63] was to correct for differences in the spatial distribution of scatter by using a convolution function to convert the spatial distribution of scatter in the Lower energy window into that of the higher energy window. The convolution function is determined empirically using water phantoms and is assumed to be spatially invariant.…”

Section: Reconstruction Filtersmentioning

confidence: 99%

Analytical calculation of photon distributions in SPECT projections

Wells

Celler

Harrop

1998

IEEE Trans. Nucl. Sci.

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In this work is presented a method for analytically cdculating the distribution of photons detected in SPECT projections. The technique is appLicabIe to sources in homogeneous and non-homogeneous media. The photon distribution (primary, first and second order Compton scatter, and first order Rayleigh scatter) is computed using precdculated camera-dependent lookup tables in conjunction with an attenuation map of the scattering object aad a map of the activity distribution.The resdts of the technique are in excellent agreement with those of Monte Carlo simulation and experimental phantom studies. It has b e n validated with respect to sources in both homogeneous and noa-homogeneous media.Compared with a similar andyticd technique, it offers a factor of 40-60 decrease in the cdculation time for higher order Compton scatter distributions. For small sources, it improves on computation tirne required by Monte Carlo simulators by a factor of 20-150.Finally, this method has been applied to the problem of correcting for cross-taik in 1231-99mT~ dual-isotope SPECT studies. It has demonstrated the ability to accurately reproduce the shape of the cross-talk distribution and to reproduce the absolute activity of the sources to within 7%, dowing accurate removai of cross-talk contamination. Abstract. . 11

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Section: Reconstruction Filtersmentioning

confidence: 99%

Analytical calculation of photon distributions in SPECT projections

Wells

Celler

Harrop

1998

IEEE Trans. Nucl. Sci.

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“…[12–13] Therefore, f t and k t in the transmission window are approximately equivalent to those from a source at the center of the object irrespective of the depth. The μd can be replaced by μT/2 , ( f t = a’ + b’ * μT/2 ) in the linear equation and buildup equation (1) can be rewritten as:…”

Section: Methodsmentioning

confidence: 99%

A new method to correct the attenuation map in simultaneous transmission/emission tomography using ¹⁵³Gd/ ⁶⁷Ga radioisotopes

Kheruka¹,

Hutton²,

Naithani³

et al. 2012

J Med Phys

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Reconstruction of the tomographic images without attenuation correction can cause erroneously high count densities and reduced image contrast in low attenuation regions. In order to solve the problem of photon attenuation, one needs to know the attenuation coefficient for the individual patient being studied. Therefore, we made an attempt to correct the attenuation map in simultaneous transmission/emission tomography with 153Gd/67Ga using maximum likelihood method using the expectation maximization (ML-EM) algorithm to correct the transmission window for both the spillover and downscatter. Spillover fraction, scatter fraction and parameters for the scatter function (A, b and c) were determined experimentally and optimized using the optimization program written in IDL based on simplex theory. All measurements were performed on a Vertex gamma camera using the anthropomorphic thorax phantom for validation of data obtained by the proposed method. It was observed that without spillover and downscatter correction, the mean counts were 19.29 in liver and 26.90 in lung, whereas after after applying the corrections, the mean counts were reduced to 3.80 and 15.10 in liver and lung, respectively, which were close to true mean counts (liver 2.15 and lung 14.89). In this proposed method, we introduced the set of Ft(spillover) and Kt(downscatter) to account for the variations in projection pixels (ft and kt) with the density and thickness. The Ft and Kt were determined using the transmission data by an iterative process. The quantitative error was reduced by 98.0% for lung and 90.0% for liver when the corrected transmission images were obtained after the subtraction of spillover and downscatter fraction.

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“…In the scatter model, we model the relationship between down-scatter projection and corresponding self-scatter projection. Generally, the down-scatter projection is a blurred version of the self-scatter projection and this blurring can be described as the combination of a δ function and a monoexponential kernel 11,22 as follows:…”

Section: B3 Scatter Model: Relationship Between Down-scatter and mentioning

confidence: 99%

Scatter and crosstalk corrections for ^99mTc/¹²³I dual‐radionuclide imaging using a CZT SPECT system with pinhole collimators

et al. 2015

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SPECT scatter correction in non-homogeneous media

Cited by 24 publications

References 3 publications

Analytical calculation of photon distributions in SPECT projections

Analytical calculation of photon distributions in SPECT projections

A new method to correct the attenuation map in simultaneous transmission/emission tomography using ¹⁵³Gd/ ⁶⁷Ga radioisotopes

Scatter and crosstalk corrections for ^99mTc/¹²³I dual‐radionuclide imaging using a CZT SPECT system with pinhole collimators

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SPECT scatter correction in non-homogeneous media

Cited by 24 publications

References 3 publications

Analytical calculation of photon distributions in SPECT projections

Analytical calculation of photon distributions in SPECT projections

A new method to correct the attenuation map in simultaneous transmission/emission tomography using 153Gd/ 67Ga radioisotopes

Scatter and crosstalk corrections for 99mTc/123I dual‐radionuclide imaging using a CZT SPECT system with pinhole collimators

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A new method to correct the attenuation map in simultaneous transmission/emission tomography using ¹⁵³Gd/ ⁶⁷Ga radioisotopes

Scatter and crosstalk corrections for ^99mTc/¹²³I dual‐radionuclide imaging using a CZT SPECT system with pinhole collimators