Heating rate modeling and measurements in phantom and in vivo of the human upper extremity in a defective 2450 MHz microwave oven.

Multiple door interlock switches in commercial microwave ovens are designed to prevent accidental exposure and injury. We report a) heating rate (°C/sec) measurements in a phantom of the human upper extremity in a 2450 MHz microwave oven having interlock switches deliberately bypassed; b) skin temperature measurements on the upper extremity of a human volunteer similarly exposed; c)perception of warmth and pain experienced by the volunteer during exposure; d) the rrno graphic camera recordings of the volunteer’s skin; and e) finite element modeling of specific absorption rate (SAR) in the volunteer’s hand. Moderately severe pain was experienced at the fingertips after 5 sec of exposure, consistent with the modeled SAR, measured heating rates, and published data on the temperature threshold for pain. We estimate that an additional 9 sec of exposure would be required to produce irreversible injury, consisting of focal thermal injury in the fingertips and possibly the thenar and hypothenar eminences.