The X-rays produced in the head exit from the tube via an opening in the casing - this forms the primary beam which is directed at the area of interest in the patient. X-rays which are oriented away from this opening are absorbed by the lead casing which surrounds the tube. | The X-rays produced in the head exit from the tube via an opening in the casing - this forms the primary beam which is directed at the area of interest in the patient. X-rays which are oriented away from this opening are absorbed by the lead casing which surrounds the tube. |