Clinical hyperthermia by microwaves: Controlling and improving quality through treatment planning

Generally, hyperthermia is applied by electromagnetic energy and requires the use of complex high technological equipment. A strong relation exists between treatment quality and clinical outcome; hence controlled delivery of heat is the Achilles heel of the treatment. Current efforts to further enhance the HT treatment quality are focusing on our ability to improve dosimetry and to prospectively prescribe thermal dose. Non Invasive Thermometry (NIT) by Magnetic Resonance Imaging (MRI) represents the most recent, major technological improvement. Using a hybrid HT system it is possible to perform on-line NIT during high power RF-heating. The results obtained with NIT by MRI-technology are very promising. The tremendous improvements in the available software for 3-D electromagnetic (EM) modeling offer unique possibilities hyperthermia treatment planning (HTP). HTP offers new ways to optimize the quality of HT to a prospectively defined level. This should be regarded as the gateway to a new decade of progress in the controlled application of HT. At the same time such progress would strongly simplify translation of knowledge from experienced to less experienced or new HT centers (education) as well as allowing a more rigid evaluation of the relation between treatment outcome and quality of the HT treatment (dosimetry). We are convinced that these efforts will improve clinical outcome and/or reduce toxicity as well as stimulates a wider use of hyperthermia.