The present invention relates to a device for simultaneously treating a tumor or cancerous growth with both hyperthermia and X-ray radiation using brachytherapy. The device includes a needle-like introducer serving as a microwave antenna. Microwaves are emitted from the introducer to increase the temperature of cancerous body tissue. The introducer is an inner conductor of a coaxial cable. The introducer contains a hollow core which houses an X-ray emitter. The X-ray emitter is connected to a high voltage miniature cable which extends from the X-ray emitter to a high voltage power source. The X-ray emitter emits ionizing radiation to irradiate cancerous tissue. A cooling system is included to control the temperature of the introducer. Temperature sensors placed around the periphery of the tumor monitor the temperature of the treated tissue.