Will Thermometric Tomography Become Practical for Hyperthermia Treatment Monitoring?1

Thermal tomography refers to the acquisition of detailed ther mal information throughout a slice of the subject. Experimental temperature information of this nature to be obtained experimen tally using some form of scanning mechanism is usually implied by the term, noninvasive thermometry. Desirable specifications for such a system are presented, and the degree to which the proposed methods are likely to achieve these are reviewed. Four major issues that must be resolved for any system to be useful clinically are: (a) will the system interfere with coupling the heating source to the patient and will the physician or technologist have access as well; (b) will its noise rejection be sufficient to operate in the presence of strong electromagnetic or ultrasonic heating fields; (c) will the spatial, temporal, and thermal resolution be sufficient to record important variations during treatments; and (d) will the parameter sensed be a function only of temperature or will it change as a consequence of physiological variations or therapeutic effects? It is concluded that noninvasive temperature scanning is unlikely to have a significant effect on thermal therapy for many years. Conversely, invasive thermometry coupled with numerical modeling is well along the way to becoming clinically