An analysis of the changes to radiation dose distributions resulting from the use of simulator computed tomography

The use of a radiotherapy simulator linked to a treatment planning computer to produce computed tomographic (CT) images for radiotherapy planning was described by Redpath and Wright (1985). Experimental results with phantoms have shown this technique to be accurate to±5 mm. Prior to the availability of CT images, the standard method of obtaining body outlines was to use the range finder on the simulator to measure the focus-skin distance at 100 intervals around the patient. A comparison between these two methods of obtaining anatomical information for planning has been carried out on 26 chest patients and 83 pelvic patients. (author)