The effect of attenuation correction on image quality in single photon emission computed tomography

Objective: Attenuation has a significant influence on data and consequently on image quality. Attenuation correction corrects the weakening of the gamma photons in various depths. Non-diagnostic, low-dosage CT is usually used for attenuation correction when images are taken with a SPECT/CT. The purpose of the study was to determine the influence of attenuation correction in SPECT/CT on image quality in NEMA body phantom analysis in different background/sphere ratios.\r\nMaterial and Methods: The NEMA IEC Body Phantom was filled with isotope technetium-99m (99mTc), with a different ratio between the phantom background and spheres. The images were reconstructed using filtered back projection (FBP), non-corrected iterative reconstruction (IR), and iterative reconstruction using computer tomography for attenuation correction (CT-AC). The average number of counts in the background and in all six spheres was measured. This was followed by a comparison of the contrast in images that were reconstructed using different methods.\r\nResults: The average number of counts in sphere increased as we increased the activity concentration ratio between the background and sphere. Statistical analysis showed that contrast is significantly divergent between different methods of reconstruction.\r\nConclusion: The use of iterative reconstruction with CT-AC improves the contrast and image quality compared to iterative reconstruction and FBP.