Design and thermometry of an intracavitary microwave applicator suitable for treatment of some vaginal and rectal cancers.

The construction of a modified coaxial cable as an intracavitary microwave applicator suitable for use in some vaginal and rectal cancers is presented. Thermometry was performed for microwave frequencies of 300, 400, 650, and 915 MHz. Temperature profiles in tissue phantoms were obtained with non-perturbing temperature probes and thermography, and the data were compared with those obtained in dogs. The temperature profiles were dependent on the frequency of the microwaves and the insertion depth of the applicator. In addition, an acrylic cylindrical spacer external to the applicator also altered the heating pattern. Therefore, with proper combinations of frequency, insertion depth and spacer, the applicator can be used for heating tumors in some clinical situations.