You will lie on a bed or treatment couch and have a local anaesthetic to numb the area. Temperature monitors are applied to the area around the tumour. Thin plastic tubes (catheters) are then inserted into the tumour and small thermometers are placed inside the catheters.
To control the skin temperature, a water bag is placed on the area to be treated. The applicator (a small metal box which contains microwave radiators) is placed on the water bag. You will be awake during the procedure and asked to remain fairly still. During the treatment, members of staff are always nearby and will come and make adjustments to the position of the applicator. Each treatment can take up to an hour and a half.
During treatment, the staff will aim to get the temperature in the tumour as high as possible without damaging nearby tissues. The temperature will be measured continually and will be increased as long as you are comfortable. If you feel symptoms such as a burning sensation or a feeling of pressure on the area being treated, it is important you tell a member of staff. It may be that the temperature is too high and needs adjusting.
You might find that your whole body temperature starts to increase during treatment. You will be kept as comfortable as possible with air conditioning, wet towels and extra ventilation.
If you are having treatment for a tumour deep within the body, you will have your blood pressure and heart rate (pulse) monitored regularly and your temperature will also be checked.
You can have a relative or friend with you in the room during the procedure. If your companion has a pacemaker or is pregnant, however, they are not allowed to stay in the treatment room.