It is important to quantify the uniformity of pixel intensity in myocardial SPECT images at varied tomographic slices. The distribution of pixel densities in SPECT images mirrored the distribution of radionuclide tracer within target organs. Non-uniformity of pixel intensities in SPECT images may lead to an incorrect diagnosis of myocardial infarction. Myocardial phantom positioning is one of the many reasons that affect pixel intensity distribution. In this research work, the Myocardial fabricated phantoms were used to mimic the myocardial wall at end-diastole and end-systole. These phantoms were separately placed at four different positions on the imaging table. The purpose of this study was to quantitatively determine the pixel intensity distribution of the reconstructed myocardial SPECT images and its relation to phantom positioning on the imaging table. Results show non-uniformity of pixel intensity of SPECT short-axis image whether the myocardial phantom was end-diastole or end-systole. The non-uniformity was not significant when reconstructed SPECT images of both stages were compared. This non uniformity became significant (p<0.05, sigma plot) with an increasing position of both myocardial phantom stages. In addition, non-uniformity became in big degree in an inferior segment more than a segment in septal, anterior, and lateral particularly, when the myocardial phantoms were positioned at 15 cm off-center.

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