Methods of External Hyperthermic Heating

The development of equipment capable of producing and monitoring safe, effective and predictable hyperthermia treatments represents a major challenge. The main problem associated with any heating technique is the need to adjust and control the distribution of absorbed power in the tissue during treatment. Power distribution is considered adequate only when tumor tissue can be maintained at the required hyperthermic levels while, at the same time, healthy tissue is not overheated. This problem is particularly crucial when external heating devices are used to produce hyperthermia. Ex ternal hyperthermia refers to those methods which supply heat to tumor tissue in an external, noninvasive manner, as opposed to internal hyperther mia by which heat is supplied to tumor tissue in situ. Until recently, most of the technical developments and clinical trials of ther motherapy for superficial and deep tumors have been based on elec tromagnetic systems. Presently, there is increasing interest in the use of ultra sound to accomplish these goals. Electromagnetic techniques of external thermotherapy include radiative, capacitive, and, to a lesser extent, inductive procedures. Recent designs for radiative applicators have incorporated microstrip structures. These have the advantage of being compact and lightweight compared with dielectrically loaded waveguide applicators.

Texte du rabat

This volume essentially deals with the electromagnetic and acoustic methods of external hyperthermia - a type of thermotherapy by which heat is supplied to tumor tissue in an external, noninvasive manner. As the development of equipment capable of producing and monitoring safe, effective, and predictable hyperthermia treatment represents a major challenge, all biophysical, biological, and technological aspects of the different heating techniques are discussed comprehensively. Particular emphasis is laid upon the problems involved in hyperthermic heating of deep-seated tumors, in particular concerning the control of power deposition pattern, and the technological advances in both radiofrequency and microwave applicators and ultrasound transducers. Methods and standards for the physical evaluation and quality assurance of hyperthermia equipment are described extensively.

Contenu
1 Biophysics and Technology of Electromagnetic Hyperthermia.- 1.1 Electromagnetic Fields and Tissues.- 1.2 Dosimetry in Electromagnetic Hyperthermia.- 1.3 Electromagnetic Techniques for Hyperthermia.- 1.4 Applicators for Local Hyperthermia.- 1.5 Applicators for Regional Hyperthermia.- 1.6 Biological Effects of RF/Microwave Fields and Exposure Standards.- References.- 2 Biophysics and Technology of Ultrasound Hyperthermia.- 2.1 Introduction.- 2.2 Basic Physics of Ultrasound.- 2.3 Acoustic Properties of Tissues.- 2.4 Biological Effects of Ultrasound.- 2.5 Generation and Characterization of Ultrasonic Fields.- 2.6 Ultrasonic Systems for Induction of Hyperthermia.- 2.7 Technical Considerations in Ultrasound Hyperthermia.- 2.8 Future Developments in Ultrasound Hyperthermia.- References.- 3 Physics Evaluation and Quality Control of Hyperthermia Equipment.- 3.1 Common Components of Hyperthermia Equipment.- 3.2 Thermometry Evaluations.- 3.3 Power Evaluations.- 3.4 Applicator Evaluations.- 3.5 Evaluation of Coupling.- 3.6 Evaluation of Skin Cooling Devices.- 3.7 Evaluation of Electromagnetic Hazard.- References.