Final answer:
The CBCT X-ray beam goes around the head 1.5 times or 450 degrees.
Step-by-step explanation:
The answer is d) 450 degrees. In a CBCT (Cone Beam Computed Tomography) scan, the X-ray beam rotates around the patient's head in a full circle, which is equivalent to 360 degrees. However, in some CBCT systems, an additional half-rotation is performed, making the total rotation 360 degrees + 180 degrees = 540 degrees. However, the question specifically asks for the number of times the beam goes around the head, not the total rotation. Therefore, the correct answer is 540 degrees divided by 360 degrees, which gives us 1.5 times or 450 degrees.