More than you probably want to know about MICS.
Established in 1999, the MICS rules apply to transmitters that support the diagnostic and/or therapeutic functions associated with implantedmedical devices to enable individuals and medical practitioners to utilize potential life-saving medical technology without causing interference to other users in the spectrum - that's the official text from the original Order.
The Commission set aside the 402-405 MHz bandbecause the signal propagation characteristics in the band are particularly well suited for implantable applications due to signal propagation characteristics in the human body, the relative dearth of other users in the band, and the ability to stake out the band internationally. The MICS use of this band is secondary to the primary users of this spectrum - Meteorological Aids Service (Medaids), the Meteorological Satellite Services, and the Earth Satellite Service.
Technical rules were established to minimize interference and ensure safe coexistence of multiple MICS devices. The MICS band is broken into 300 kHz wide channels. The rules specify that devices must "listen" for other devices before transmitting, called Listen Before Talk (LBT). If interference is encountered, the radio switches channels and listens again - known as "frequency agility." The rules also allow MICS devices to transmit without prior frequency monitoring in response to a non-radio frequency actuation signal generated by a device external to the body (i.e., manual activation), or in response to a medical implant event (i.e., alert or alarm condition).
You can read more about MICS here (FCC Deals with MICS - Vendors Help and Hinder), here (FCC Announces Regulatory Changes for Wireless Medical Devices) and here (Medtronics Brags on New Wireless ICD).