What type of artifact can occur when CT scans are reconstructed with a smaller bore diameter for PET/CT-AC?

Truncation artifacts occur when the data collected by the CT scan is insufficient to fully represent the object being imaged, particularly in cases where the bore diameter is smaller. In PET/CT imaging, when the CT scans are reconstructed from data acquired in a smaller bore, areas of the anatomy at the edges of the field of view may not be captured completely. This results in discontinuities or gaps in the reconstructed image, leading to noticeable artifacts in the final output.

These artifacts are most pronounced when parts of the structure being scanned extend beyond the limited field of view of the CT, which is often the case with larger patients or certain imaging protocols. This incomplete representation of the anatomy affects the accuracy and reliability of the attenuation correction process used in PET imaging, potentially compromising the quality of the subsequent PET images.

Understanding truncation artifacts is crucial for interpreting PET/CT scans because they can mimic pathology or obscure the actual distribution of radiopharmaceuticals within the body. Therefore, it’s vital to approach the imaging protocol with considerations for bore size and field of view to minimize the impact of such artifacts.