What term describes the relationship between collimation and the table movement per gantry rotation?

The term that describes the relationship between collimation and the table movement per gantry rotation is pitch. Pitch is a key concept in computed tomography that reflects the ratio of the distance the table moves in one gantry rotation to the width of the x-ray beam collimation.

When the pitch value is calculated, it helps determine how much of the anatomy is covered per rotation of the gantry and thus influences image quality, radiation dose, and scan time. A higher pitch means the table moves a greater distance relative to the collimation width, leading to quicker scans but potentially less detailed images due to gaps in coverage. Conversely, a lower pitch results in more overlap in the scanned areas, improving the image quality but increasing the radiation dose and scan time.

Understanding pitch is critical for optimizing scan parameters to balance image quality, patient safety, and overall efficiency in CT imaging.