Final answer:
Helical Scanning is the acquisition mode where the patient table is in constant motion. In contrast, MRI scanners produce images in the frontal plane by aligning with the front and back, and in the sagittal plane by aligning with the left and right sides, using magnetic fields and radio waves.
Step-by-step explanation:
The mode of acquisition in which the patient table is in constant motion is known as Helical Scanning. In helical or spiral scanning, the patient table moves continuously through the rotating x-ray beam, which allows for the collection of data in a helix manner rather than taking individual axial slices. This technique is distinct from axial scanning, where the table moves incrementally, stopping to take each slice before moving on, and volume scanning, where multiple detectors are used to capture large volumes at once without the need for table movement.
For MRI scanners, to produce sequential images of the body in the frontal plane (coronal plane), the scanner would move in the direction that aligns with the patient's front and back sides. Conversely, to produce sequential images in the sagittal plane, the scanner would move in the direction that aligns with the patient's left and right sides. The direction and plane of imaging rely on the orientation of the magnetic fields and radio waves used to create MRI images, which is different from the mechanical movement of the CT scanner table in helical scanning.