ABSTRACT
This chapter focuses on noninvasive (NI) medical measurements. Any measurement system that does not physically breach the skin, or enter the body deeply through an external orifice is truly NI. Thus, the measurement of body temperature with a thermometer in the mouth, rectum, or ear canal is considered NI, as is the use of an otoscope to examine the outer surface of the eardrum. Endoscopy is a technique for visualizing tissues deep within the body yet topologically on the outer surface of the body. Some endoscopes are used invasively, such as laparoscopes, which are inserted into the abdomen through a small incision in the wall of the abdomen, chest, or back. NI medical instruments can be broadly classified between those passive systems that put no energy into the body, and those that input some form of radiation energy, for example, microwaves, visible and UV light, x-rays, γ-rays, sound and ultrasound, and measure what energy is either absorbed, reflected, or transmitted.
