Wireless transmission/Confidential Info

We currently are an AS/400 based network. Switching to a PC(NT) network. We deal with patients whose information is protected by Federal Confidentiality laws similar to Medical and Psychological information. The company installing the new system is suggesting some wireless technology and possibly ALL wireless. Not knowing enough about this stuff, I am concerned about your private(assuming you were my patient) being in any danger of being intercepted. Is protection for wireless networking good enough to make you feel safe about your personal life being transmitted thru the sky?