X-rays and CT Scans

- The X-rays are focused on the tumour using a wide beam.

- This beam is rotated around the patient with the tumour at the centre.

- This minimises the exposure of normal cells to radiation, and so reduces the chances of damaging the rest of the body. 

- The patient is put inside the cylindrical scanner

- An x-ray beam is fired through the body from an x-ray tube and picked up by detectors on the opposite side.

- The x-ray tube and detectors are rotated during the scan.

- A computer interprets the signals from the detectors to form an image of a two-dimensional slice through the body.

- Multiple two-dimensional CT scans can be put together to make a three-dimensional image of the inside of the body.