Future trends in heating technology of deep-seated tumors

Hyperthermia techniques and equipment have developed into a level of sophistication requiring special training and operator skills. Recent advances electromagnetic and ultrasound heating techniques are multi-applicator arrays, both external and invasive. These arrays are most effective when individual channel power control can be utilized to improve the heating pattern control during treatment. A preview of future capabilities shows that more selective tumor heating is possible with the advanced equipment. The role of computer pretreatment planning is a valuable aid in operator training as well as optimization of parameters. The current development of regional heating is in the deep focal heating by external focused arrays. The SIGMA 60 cylindrical dipole array deep steerable focal zone is described and test data presented showing the selective focusing obtained. A small invasive targeting E-field sensor is used to optimize phase and amplitude of the array to improve the selective heating in the target zone. These patented techniques and devices are expected to reduce systemic toxicity and increase tumor temperatures with lower power input. Future equipment development is predicted to include many types of hyperthermia devices and techniques. This trend suggests that systems must be designed to simplify the operator's tasks and improve the heating pattern controls. The computer power and control will become much more important in these future systems.