Location tracking of a metallic object in a living body

Abstract

A method and apparatus are provided for determining and tracking location of a metallic object in a living body, and then directing a second modality such as ultrasound waves to the determined location. The metal detector may be a radar detector adapted to operate on a living body. The adaption may include disposing a transfer material having electromagnetic properties similar to the body between the radar detector and the living body, ECG gating the radar detector, and/or employing an optimal estimator with a model of expected stent movement in a living body. Applications include determination of extent of in-stent restenosis, performing therapeutic thrombolysis, or determining operational features of a metallic implant.

1 - 51 . (canceled) 
     
     
         52 . A radio-frequency (RF) based monitoring and/or diagnostic apparatus, comprising:
 a transmitting RF antenna configured to transmit RF waves into the body of a patient;   an RF detector configured to receive scattered RF waves in response to the transmitted RF waves from the body of the patient;   a patch comprising at least one of the transmitting RF antenna and the RF detector, the patch configured to couple to and conform with skin of the patient; and   processing circuitry for determining information related to a target feature of the body of the patient by analyzing a characteristic of the received scattered RF waves.   
     
     
         53 . The apparatus of  claim 52 , further comprising an interface configured to facilitate the coupling of the patch to the skin of the patient. 
     
     
         54 . The apparatus of  claim 53 , wherein the interface comprises an apparel to be worn by the patient. 
     
     
         55 . The apparatus of  claim 53 , wherein the interface comprises a transfer material configured to reduce reflection of the transmitted RF waves at the skin of the patient. 
     
     
         56 . The apparatus of  claim 55 , wherein the transfer material comprises one or more of a gel, a liquid, an adhesive and a solution of ethylene glycol and water. 
     
     
         57 . The apparatus of  claim 53 , further comprising a container for enclosing the interface, the container configured to allow the coupling of the patch to the skin of the patient. 
     
     
         58 . The apparatus of  claim 52 , wherein the RF detector is configured to operate in a bandwidth of several GHz in a range of about 1 GHz to about 10 GHz. 
     
     
         59 . The apparatus of  claim 52 , wherein the antenna is a multi-element antenna. 
     
     
         60 . The apparatus of  claim 59 , further comprising a switching matrix configured to switch elements of the multi-element antenna into one or more receivers to receive the scattered RF waves. 
     
     
         61 . The apparatus of  claim 52 , further comprising a modulating matrix configured to modulate the received scattered RF waves. 
     
     
         62 . The apparatus of  claim 52 , further comprising a tracking element configured to provide a location of the patch. 
     
     
         63 . The apparatus of  claim 52 , wherein the information related to the target feature includes target location and target orientation. 
     
     
         64 . The apparatus of  claim 52 , wherein the characteristic of the received scattered waves includes spectral characteristics, temporal characteristics, amplitude information and/or Doppler velocity of the received scattered waves. 
     
     
         65 . The apparatus of  claim 64 , wherein the characteristic of the received scattered waves includes amplitude information, and analyzing the characteristics includes evaluating amplitude ratios to determine target location. 
     
     
         66 . The apparatus of  claim 64 , wherein the characteristic of the received scattered waves includes temporal characteristics, and analyzing the characteristics includes evaluating arrival time differences of the received scattered waves to determine target location. 
     
     
         67 . A radio-frequency (RF) based monitoring and/or diagnostic apparatus, comprising:
 a transmitting RF antenna configured to transmit RF waves into the body of a patient;   an RF detector configured to receive scattered RF waves in response to the transmitted RF waves from the body of the patient;   an electrocardiogram (ECG) device configured to monitor an activity of the heart of the patient; and   processing circuitry for managing a duty cycle of the transmitting RF antenna and/or the RF detector based on the monitored activity of the heart.   
     
     
         68 . The apparatus of  claim 67 , wherein the processing circuitry determines information related to a target feature of the body of the patient by analyzing a characteristic of a duty-cycled received scattered RF waves. 
     
     
         69 . The apparatus of  claim 68 , further comprising a sensor for measuring a breathing motion of the patient, and wherein the processing circuitry uses breathing motion information from the sensor to monitor a location of the target feature. 
     
     
         70 . A radio-frequency (RF) based monitoring and/or diagnostic apparatus, comprising:
 a transmitting RF antenna configured to transmit RF waves into the body of a patient;   an RF detector configured to receive scattered RF waves in response to the transmitted RF waves from the body of the patient;   an electrocardiogram (ECG) device configured to monitor an activity of the heart of the patient;   a patch comprising at least one of the transmitting RF antenna, the RF detector and the ECG device, the patch configured to couple to and conform with skin of the patient;   a transfer material configured to surround and/or enfold the antenna so as to reduce reflection of RF waves at the skin of the patient; and   processing circuitry for managing a duty cycle of the transmitting RF antenna and/or the RF detector based on the monitored activity of the heart, and determining information related to a target feature of the body of the patient by analyzing a characteristic of a duty-cycled received scattered RF waves.   
     
     
         71 . The apparatus of  claim 70 , wherein the transfer material has electromagnetic properties similar to the body of the patient.