Temperature and blood flow measurements in and around 7,12-dimethylbenz(a)anthracene-induced tumor and Walker 256 carcinosarcomas in rats.

By means of an implanted transmitter, a circadian rhythm of temperature was found both in 7,12-dimethylbenz(a)anthracene-induced tumors and in Walker 256 carcinosarcomas. There was no significant difference in the temperatures of the two tumors. The temperature was lowest in periods of rest, and the temperature difference between light and dark periods was about 1 degree. Both tumors were found to have a higher temperature than that of s.c. tissue. External temperature measurements of the skin covering the 7,12-dimethylbenz(a)anthracene-induced tumor by thermistor probe and by thermography showed a temperature 1-2 degrees below the temperature of surrounding skin areas. In the 7,12-dimethylbenz(a)anthracene-induced tumors the blood flow was low, which should correspond to a relatively small heat production, although the temperature was relatively high. Blood flow in skin overlying tumor was high, presumably a perifocal hyperemic reaction, although the temperature was relatively low in this area. Thus tissue temperatures was not indicative of blood flow.