Abstract
Radiotherapy is useful in the palliative treatment of many large incurable tumours. This study evaluates the effectiveness of computed tomography (CT) as an adjunct in the radiotherapy planning of these patients. Forty‐five patients had their treatment fields simulated using findings from physical examination, x‐rays etc. The patients were then scanned under conditions simulating the radiotherapy and the dosimetry was recalculated. CT scanning was found to be valuable in the radiotherapy planning in 56% of the treatment series (field geometry: 27% dosimetry: 46%).