Abstract: Since 9·11, airliner has become a “powerful tool” for terrorists. In this deteriorating security situation, body inspection system has made great progress in last decade, but still a weak link in modern airport security system. This paper explains the concept of body inspection system, discusses the use of three mainstream technologies in recent years through a patented statistical analysis.

Key words: body inspection system, patent analysis, millimeter-wave, THz, backscatter