Hyperthermia quality assurance results.

The Hyperthermia Physics Center (HPC), under contract with the National Cancer Institute (NCI), has conducted review-type quality assurance (QA) measurements at the five Hyperthermia Equipment Evaluation Centers involved in evaluating the clinical efficacy of a variety of devices for delivering heat treatments to deep-seated human tumours. A summary of the QA protocol, results, testing procedures, standards, criteria, conclusions and recommendations are presented in this paper. The QA review measurements indicate (a) that 81.5 per cent of temperatures surveyed were within the 0.2 degrees C HPC criterion (91 per cent were within 0.4 degrees C), (b) that only 66 per cent of power indications were within the 10 per cent criterion, (c) that the heat patterns in a phantom produced by the BSD Annular Phased Array (AA) had significant variability, (d) that each treatment facility had at least a few potentially occupiable locations where the maximum permissible American National Standards Institute standards of electromagnetic leakage were exceeded, and (e) that these levels of accuracy and safety were achieved only after stringent inhouse QA efforts. From the combined data, it is concluded that the temperature accuracy in this cooperative trial was sufficient to justify a common analysis of clinical data as presented in this series. Also, stringent quality control of every parameter must continue to be stressed in all future hyperthermia trials.