Hypodermic Thermocouple Tissue Cryometers

摘要

The investigation was performed first to determine the effects of thermal 'pipelining' along the needle shaft and secondly to develop a test method for measuring the accuracy of the cryometer units. The pipelining effect arise from the fact that stainless steel hypodermic needles are better thermal conductors than the surrounding tissue into which they are inserted. These effects include potentially inaccurate indications of tissue temperature when the thermocouple is cooled as heat is drawn from the hypodermic shaft rather than the surrounding tissue. Secondly, there is some concern that the thermocouple may adversely perturb the thermal field in the tissue. Both effects were demonstrated in the lab. However, it appears that in general careful attention to technique in using hypodermic thermocouples can greatly alleviate these problems.