What artifact can occur due to patient movement between CT and PET scans?

The correct answer regarding the artifact that can occur due to patient movement between CT and PET scans is the mushroom artifact. This artifact is a result of the misalignment of data from the two modalities. When a patient's position changes between the CT scan (which provides anatomical information) and the PET scan (which provides functional information), the different datasets can lead to discrepancies in the reconstructed images. This misalignment can cause the appearance of the mushroom artifact, characterized by distorted shapes or unexpected visual representations in the fused images.

Understanding the implications of patient motion is crucial in imaging, as it directly affects diagnostic accuracy. Therefore, it is important to minimize movement during imaging procedures to ensure both the CT and PET datasets align correctly, enhancing the quality of the resulting images.