Preliminary study of ring artifact detection in SPECT imaging using Jaszczak phantom

Inspection of imaging SPECT system performance was controlled by Quality Control (QC) regularly. Tomographic imaging parameters in QC, i.e. homogeneity, contrast, and spatial resolution should be tested. These results make it reliable whether the SPECT system will be used. The modular Jaszczak phantom was used for that purpose, as it offers the investigation to all three parameters with a single measurement. Compared to the contrast and spatial resolution, an objective identification of possible ring artifact in the homogeneity is challenging. Artifact simulation of SPECT images which have been generated by disturbance of 4 × 4 cm² copper sheet located on surface LEHR collimator have been conducted to study the detectability of ring artifact. Uniformity section of Jaszczak phantom which filled with ^99mTc was used for acquisition. The confirmed ring artifact was analyzed by Edge Detection and Circle Hough Transform provided by imageJ, and students t-test statistically. From the evaluation by edge detection and circle Hough transform, the present of ring artifact only detected in artifact SPECT images using 1.00, 0.75, and 0.50 mm copper sheet thickness, while in t-test method all copper sheet thickness (including 0.25 mm) detect ring artifact in images.