Investigation of changes in CT-number in the prostate after radiotherapy.

From October 1980 until September 1982, 60 patients with a prostatic carcinoma were studied with computed tomography (CT). Evaluation of the CT numbers was one of the purposes. Patients were scanned before, directly after, 3 months after and 6 months after radiotherapy. Complete data were available for 41 patients. The mean CT number in the prostate from the first 32 patients without reference measurements showed no systematic changes. For the last 9 patients, reference measurements were carried out to eliminate a possible effect of machine fluctuations. For all patients the conclusion remained the same: no significant changes occur in the mean CT number in the prostate before and after radiation of the pelvis.