Has CT scanning a role to play in radiotherapy planning? Computer dose calculations.

Successful radiotherapy practice depends on the irradiation of tumours such that their destruction follows without unacceptable damage to the surrounding normal tissues. In order to assess the place of computed tomography (CT) in radiotherapy planning, the tumour target volumes were localized both by conventional techniques and with CT scanning under conditions simulating the radiotherapy. One hundred and eighty seven consecutive patients with various malignancies were examined. CT scanning was found to be valuable in the assessment of the radiation dose calculations in 39% of the treatment series (pelvis tumours 31%, chest wall tumours 22%, intrathoracic tumours 58%, palliative treatment group 46%).