A radiation-based timer for use in an implantable medical device (IMD) includes a radiation source and a radiation detection circuit. The radiation source emits radiation particles during a process referred to as radioactive decay. The radiation detection circuit detects the radiation particles emitted...http://www.google.de/patents/US7935935?utm_source=gb-gplus-sharePatent US7935935 - Radiation-based timer for implantable medical devices
