Bar phantom image
View main image(mm) in a separate image viewer
Full history/Diagnosis is available below
There are two common causes for Moire patterns. First, when a 4-quadrant bar pattern is used with the collimator in place, Moire patterns will be present due to the interplay between the bars of the test pattern and holes of the collimator. Due to the increased thickness of the septa, medium and high energy collimators are more likely to cause Moire patterns and are rarely used when acquiring a bar phantom image.
A second common cause for the Moire pattern is the use of too small of a matrix size while acquiring the image. Moire patterns can be prevented by the use of 512 x 512 or 1024 x1024 image matrices. The bar pattern shown in this case was obtained with a low energy collimator, but the techologist acquired this digital image with a 128 x 128 matrix. This large pixel size led to the Moire pattern observed.
References and General Discussion of Bone Scintigraphy (Anatomic field:Skeletal System, Category:Normal, Technique, Congenital Anomaly)
Search for similar cases.
Edit this case
Add comments about this case
Read comments about this case
Return to the Teaching File home page.
Copyright by Wash U MO