A technique for combining microwave hyperthermia with intraluminal brachytherapy of the oesophagus

Abstract

A technique for combining microwave hyperthermia with ¹⁹²Ir brachytherapy for the treatment of oesophageal carcinoma is described. This approach uses an intraluminal afterloading applicator and up to six microwave antennae to deliver both hyperthermia and brachytherapy, with minimal modification of the existing procedure for brachytherapy alone. Each microwave antenna includes a built-in thermistor to control temperature and balance power. Longitudinal temperature distributions were measured in situ from within the applicator, and at the applicator-tissue interface in vivo. Two-dimensional SAR and steady-state temperature distributions measured in muscle-equivalent phantom are presented and discussed. The technique appears to be capable of elevating tissue temperature to greater than 42°C in a radially symmetric volume of length greater than 5 cm, with radial penetration of 0 5 cm. The clinical technique is relatively simple and well tolerated.

Key Words:

• hyperthermia
• oesophagus
• microwave
• intraluminal
• brachytherapy.