Apparatus for medical instrument placement verification

Abstract

An apparatus for verifying the proper placement of a medical instrument, such as a needle, with respect to an implantable medical device, such as a drug dispensing port or pump. The apparatus includes an internal circuit which is implantable within the body tissue, and an external circuit for communicating with the internal circuit. The internal circuit includes an electrically conductive plate for sensing proper contact between the medical instrument and the medical device. A resonant circuit is coupled between the plate and the body tissue, and has a predetermined resonance frequency, such that an electrical path is established through the resonant circuit, the plate, the body tissue and the medical instrument when the medical instrument is in proper contact with the medical device. The external circuit includes a transmitter circuit for sending signals either pulsed or continuous to the resonant circuit. The transmitted signals have a frequency equal to the resonance frequency, for causing the resonance circuit to resonate when the medical instrument is not properly placed with the respect to the implantable medical device. A receiver circuit detects the resonance signals generated by the resonant circuit, and an alarm circuit responds to the receiver circuit for generating an appropriate alarm signal.

Dependencies are inferred from the claim text.