Abstract: A needle is provided that has terminals located at or near its tip. The terminals are connectable to an impedance calculating circuit configured to enable the impedance calculating circuit to apply an alternating current input electrical signal to the terminals. The terminals are further configured to enable the impedance calculating circuit to measure a resultant electrical signal and calculate an impedance of biological tissue surrounding the tip. The needle may further include light transmitting media, that extends along the needle, and that is connectable to a light circuit. The light circuit may include an emitter/detector pair for transmitting light from the emitter, along the media, and emitting the light from the tip. A reflection of the emitted light may be transmitted from the tip to the detector and the light circuit may calculate the light absorption of the tissue.

Abstract: A needle is provided that has terminals located at or near its tip. The terminals are connectable to an impedance calculating circuit configured to enable the impedance calculating circuit to apply an alternating current input electrical signal to the terminals. The terminals are further configured to enable the impedance calculating circuit to measure a resultant electrical signal and calculate an impedance of biological tissue surrounding the tip. The needle may further include light transmitting media, that extends along the needle, and that is connectable to a light circuit. The light circuit may include an emitter/detector pair for transmitting light from the emitter, along the media, and emitting the light from the tip. A reflection of the emitted light may be transmitted from the tip to the detector and the light circuit may calculate the light absorption of the tissue.