TEMPERATURE MEASUREMENTS OF LOCALIZED PATHOLOGICAL PROCESSES *

As infrared scanners are becoming more efficient due to their shorter scan time, increased temperature sensitivity, better optical resolution and general reliability, new calorimetric problems are conling into focus. It is an old saying that in medical o r any other kind of research, the solution of one problem leads to 20 new ones. Some of these new ones are dismaying in their complexity, while others are rather straightforward. Infrared medical investigations have lacked impetus until recently, due to the high expense and lack of interest by research sponsoring organizations. I t has been impossible to evaluate many promising applications of this technology because of the poor quality and inconsistency of the images. However current enthusiasm by medical electronic groups stimulated by the promise of wide practical uses is now making practical a new look at this important medical frontier. New tools are becoming available, suitable for studying previously unapproachable aspects of human physiology, biochemistry and pharmacology. In fact these sciences are now subdivided into the specialized branches of thermophysiology, thermobiochemistry and thermopharmacology, disciplines which deal with the study of body heat transfer and endo and exothermic chemical reactions. In addition, fresh explorations have become feasible concsning the thermodynamics of blood gas exchange. Human life is possible only within an extremely narrow temperature range and for its protection the body possesses many physiological thermorepiilatory mechanisms. I t is interesting that some of these mechanisms are much less efficient in the very young and also in the older age groups. For practical purposes, all body heat comes from exothermic biochemical conibusiion at the cellular level. Body heat represents the energy difference between endo and exothermic metabolism. This heat is internally distributed by conduction, effected by the arterial, venous and lymph circulations. External losses by radiation, convection and conduction are sensitively controlled by environmental conditions. ' Temperature governs the rate of all chemical reactions. In exothermic reactions the amount of heat produced depends on the speed and quantity of reaction. I t should be obvious that temperature measurements are the most important of any biological observation that it is possible to make. Heat is the common denominator of all energy. But this energy is extremely unstable. It is constantly being transferred and incorporated into other forms of energy or matter. I t is this basic process of energy turnover that makes all forms of life possiblc. Hence the study of thermal situations should rate a higher priority in experimental work than it has so far received. This is particularly true now that improved measuring techniques are available. We have appreciated for some time that metabolic rates are a local phenomenon and differ in different parts of the body, no doubt due to different types of chemical reactions and varying speeds of reactions. This activity may be reflected by local temperatures. For instance, the renal vein is hotter than the renal