Reflector markers and systems and methods for identifying and locating them

A system for localization of a marker within a target tissue region within a patient's body, comprising:

• a probe comprising one or more antennas for transmitting a radar signal into a patient's body towards a marker and receiving a reflected signal from the marker, and a light source for delivering infrared light pulses into the patient's body to cause the marker to change its reflective properties;
• a signal generator for generating a substantially continuous wave;
• a divider coupled to the signal generator for dividing the wave into first and second signals, the first signal delivered to the one or more antennas to transmit a substantially continuous transmit signal;
• a phase splitter coupled to the divider for receiving the second signal creating a replica signal out of phase with the second signal;
• first and second mixers coupled to the phase splitter for receiving the second signal and the replica signal, respectively, and coupled to the one or more antennas for receiving the reflected signal such that the first mixer mixes the second signal and the reflected signal and the second mixer mixes the replica signal and reflected signal to produce IF signals comprising components associated with modulation of amplitude and phase of the reflected signal caused by the light pulses changing the reflective properties of the marker;
• and
• a processor coupled to the mixers comprising a synchronous modulation detector that processes the IF signals to provide an output indicative of range from the one or more antennas to the marker based at least in part on the modulation of amplitude and phase synchronous with the light pulses delivered by the light source.

A method for localization of a marker within a target tissue region within a patient's body, comprising:

• implanting a marker within a patient's body;
• placing a tip of a probe adjacent the patient's body oriented towards the marker;
• and
• activating the probe to a) transmit a substantially continuous radar signal into the patient's body, b) receive a reflected signal from the patient's body, c) in synchronization with transmitting the radar signal, deliver light pulses into the patient's body such that the marker transforms the light pulses into electrical energy to open and close a switch in the marker to modulate the reflected signal reflected by the marker, and d) process the reflected signal using a synchronous detector to measure amplitude of modulation caused by light pulses and provide an output indicative of range from the tip of the probe to the marker.

A marker sized for introduction into a target tissue region within a patient's body, comprising:

• a ceramic substrate;
• one or more photosensitive diodes configured to convert light pulses received from a light source to generate a voltage;
• a switch coupled to the one or more photosensitive diodes such that the energy pulses generate a voltage to cause the switch to open and close;
• and
• one or more antennas printed on a surface of the substrate and coupled to the switch, the switch configured to open and close to modulate signals reflected by the one or more antennas back to a source of the signals.

A system for detecting and/or locating a plurality of markers implanted within a body, the system comprising:

• one or more antennas for transmitting a radar signal into a patient's body towards a marker and receiving a reflected signal from the marker;
• a light source for delivering infrared light pulses into the patient's body to cause the marker to change its reflective properties;
• and
• one or more processors coupled to the light source for including bit codes in the light pulses to activate individual markers corresponding to the bit codes, the one or more processors further configured to process the reflected signal to provide an output indicative of range from the one or more antennas to the activated markers.