The major two areas of concern for medical device EMC are: (1) device emissions and the effects of these on other devices and (2) the immunity from (or, conversely, the susceptibility to) the EM energy that is expected in the environment where medical devices are used. The key to EMC is to minimize the emissions and to maximize the immunity. In most cases, these two areas interplay. By minimizing the emissions with proper design and shielding, the susceptibility is also changed, and immunity to EMI is improved. The key point to remember is that both emissions and immunity are important parts of the drive toward medical device EMC. The AAMI TIR 18-1997 “Guidance on Electromagnetic compatibility of Medical Devices for Clinical/Biomedical Engineers-Part 1: Radiated Radio Frequency electromagnetic Energy” contains an excellent overview of medical device EMI concerns and ways to address these concerns for the biomedical/clinical engineer (AAMI, 1997). The JCAHO Environment of Care Series: EC/PTSM Series No. 2 contains several articles in this area. Also, see Geddes (1998) for examples of medical device EMI and Kimmel and Gerke (1995) for a good overview of medical device EMI/EMC and how to design, build, and test equipment for immunity to most common EM energy