Non-invasive measurements

A large number of non-invasive measurement techniques have been developed and some have reached high levels of sophistication particularly in the medical field. The author reviews these techniques with a brief explanation of basic principles followed by examples from a broad spectrum of applications. The methods covered include ultrasonic, thermal, optical, radiation and nuclear methods, nuclear magnetic resonance and various imaging techniques based on them. The latter include computer-aided tomography, NMR imaging and positron emission tomography.