Prediction of treatment temperatures in clinical hyperthermia of locally advanced breast carcinoma: the use of contrast enhanced computed tomography.

ABSTRACT

PURPOSE: Nineteen patients with locally advanced breast carcinoma were subjected to computed tomography examinations prior to thermoradiotherapy. Pre- and postcontrast computed tomography images were obtained, and tumor contrast enhancement was studied in relation to tissue perfusion, PERF, and steady state temperature, TS, in an attempt to develop an assay for prediction of treatment temperatures in clinical hyperthermia of breast carcinoma. METHODS AND MATERIALS PERF and TS were calculated from temperature data achieved during the first fraction of the heat treatment regimen. The computed tomography images were subjected to image analysis, and two parameters representing tumor contrast enhancement were calculated from the computed tomography numbers; the absolute increase in mean attenuation, delta N, and the fraction of the postcontrast attenuation values that was higher than the mean precontrast attenuation value, F+C. RESULTS: delta N and F+C were clearly correlated to each other. The two parameters differed considerably among the patients, showing that the accumulation of contrast medium was higher in some tumors than in others. Tumor contrast enhancement increased with increasing PERF, suggesting that the accumulation of contrast medium in the tumors was determined mainly by the effective tissue perfusion. There was also a clear correlation between tumor contrast enhancement and TS. The tumors showing a high accumulation of contrast medium were more difficult to heat than those showing a low accumulation. CONCLUSION: The results indicate that contrast enhanced computed tomography images may give information about the treatment temperatures that can be achieved in clinical hyperthermia of breast carcinoma. The computed tomography images may possibly be used to predict those tumors that can be heated to therapeutic temperatures.