Naslov
Monte Carlo-based down-scatter correction of SPECT attenuation maps

Autori
Bokulić, Tomislav ; Vastenhouw, Brendan ; de Jong Hugo W. A. M. ; van Dongen, Alice J. ; van Rijk, Peter P. ; Beekman Freek, J.

Izvornik
European Journal of Nuclear Medicine and Molecular Imaging (1619-7070) 31 (2004), 8; 1173-1181

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
quantitative SPECT; attenuation correction; Monte Carlo simulation; scatter correction; cardiac imaging

Sažetak
Combined acquisition of transmission and emission data in single-photon emission computed tomography (SPECT) can be used for correction of non-uniform photon attenuation. However, down-scatter from a higher energy isotope (e.g. 99mTc) contaminates lower energy transmission data (e.g. 153Gd, 100 keV), resulting in underestimation of reconstructed attenuation coefficients. Window-based corrections are often not very accurate and increase noise in attenuation maps. We have developed a new correction scheme. It uses accurate scatter modelling to avoid noise amplification and does not require additional energy windows. The correction works as follows: Initially, an approximate attenuation map is reconstructed using down-scatter contaminated transmission data (step 1). An emission map is reconstructed based on the contaminated attenuation map (step 2). Based on this approximate 99mTc reconstruction and attenuation map, down-scatter in the 153Gd window is simulated using accelerated Monte Carlo simulation (step 3). This down-scatter estimate is used during reconstruction of a corrected attenuation map (step 4). Based on the corrected attenuation map, an improved 99mTc image is reconstructed (step 5). Steps 3– 5 are repeated to incrementally improve the down-scatter estimate. The Monte Carlo simulator provides accurate down-scatter estimation with significantly less noise than down-scatter estimates acquired in an additional window. Errors in the reconstructed attenuation coefficients are reduced from ca. 40% to less than 5%. Furthermore, artefacts in 99mTc emission reconstructions are almost completely removed. These results are better than for window-based correction, both in simulation experiments and in physical phantom experiments. Monte Carlo down-scatter simulation in concert with statistical reconstruction provides accurate down-scatter correction of attenuation maps.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kliničke medicinske znanosti

Napomena
Bokulic T. Vastenhouw B. de Jong HWAM. van Dongen AJ. van Rijk PP. Beekman FJ. Monte Carlo-based down-scatter correction of SPECT attenuation maps (vol 31, pg 1173, 2004). [Correction, Addition] European Journal of Nuclear Medicine & Molecular Imaging. 31(10):1451, 2004 Oct.

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