What function do movable lasers serve in the CT scanner?

Movable lasers in a CT scanner are primarily used for projecting field size and coordinates. This function is crucial because it assists radiologic technologists in accurately positioning the patient within the scanner to ensure that the area of interest is correctly aligned with the imaging system. By projecting precise markings on the patient's body, the lasers help to achieve optimal imaging results, reduce the need for repeat scans, and ensure that the necessary anatomical areas are included while minimizing exposure to unnecessary radiation. Therefore, the correct answer highlights the important role of movable lasers in the proper setup of the CT imaging process.