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Comparison of acquisition and reconstruction parameters in a normal cardiac phantom using SPECT/CT

¹ Nuklearmedizinische Klinik, TU Muenchen, Muenchen, Germany

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Objectives: Myocardial perfusion imaging is a well established procedure. However, due to photon attenuation, its specificity can be limited. Implementations of attenuation correction (AC) showed in the past variable success but appear to have improved with the integration of CT systems. We assessed uptake homogeneity in different settings to delineate the baseline variability.

Methods: Two different sized torso phantoms were imaged in a Siemens Symbia T6 SPECT/CT using 99mTc solutions in the heart and as a reference in an HR+ PET and a Biograph16 PET/CT using FDG. One phantom did not contain a lung insert and was completely filled with water thus creating maximal absorption and the other one had a lung model with a physiological density thus maximizing tissue inhomogeneity. SPECT image reconstruction involved filtered back projection and iterative reconstruction with scatter correction and resolution recovery. Phantoms were filled and imaged twice to exclude inhomogeneous mixture. Using polar map analysis, tracer distribution was extracted and mean, standard deviation and the anterior/inferior ratio (A/I) was determined.

Results: NonAC SPECT showed an A/I of 72% and 68% for the two phantoms almost independently of the imaging parameters. The tracer distribution was 75±14% and 73±16%. With all corrections, the A/I reached 98% and 97% which did statistically not differ from the PET. Without scatter corrections, however, A/I was reduced to 85% and 83%. Comparing the uptake homogeneity, the AC-SPECT showed 88±9% and 86±10% which is moderately worse than the PET values (92±5%).

Conclusions: In a normal phantom, CT-AC results for a wide range of acquisition and reconstruction parameters in an uptake homogeneity which reach almost the quality of PET scans without showing an over correction of the inferior wall.

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Henke, N. Articles by Nekolla, S. PubMed Articles by Henke, N. Articles by Nekolla, S.