New technique for mediastinal temperature measurement in hyperthermic cancer treatment: balloon catheter in the azygos vein.

The temperature in the mediastinum during hyperthermia is difficult to determine accurately. We measured the temperature in the azygos vein, using a new technique, and compared the measurements with temperatures in the oesophagus. Eight patients with mediastinal tumours resulting from lung cancer or oesophageal cancer were given hyperthermo-radiotherapy. The temperatures in the azygos vein and in the oesophagus were measured before and during blockage of the blood flow of the azygos vein using an angiographic balloon catheter. None of the patients had complications as a result of these procedures, and hyperthermia by capacitative heating was safely performed. The temperature in the azygos vein increased by a mean of 1.7 degrees C (0.2-2.8 degrees C) after blockage of the blood flow. The temperature in the oesophagus was 0.83 +/- 1.09 degrees C (mean +/- SD) higher than that in the azygos vein. Measurement of the temperature in the azygos vein gives a more accurate estimate of mediastinal temperature than does oesophageal temperature but it is an invasive procedure.