The effect of air cooling on the radial temperature distribution of a single microwave hyperthermia antenna in vivo.

Canine skeletal muscle was heated with a single microwave antenna within a brachytherapy catheter driven at 2000 MHz. The radial, steady-state temperature distribution was measured with and without air cooling of the antenna, as produced by room temperature air flowing in the catheter at 7.5 l/min. The axial temperature distribution was also measured with air cooling. In the antenna junction plane the area heated to a given temperature increased by a factor of four with air cooling when the same antenna temperature was enforced. With the same maximum temperature enforced, the area would increase by a factor of 2.5 with air cooling. The axial temperature distribution was not compromised by air cooling.