System and methods for triggering a radiofrequency transceiver in the human body

Abstract

Systems and methods described herein use near field communications to locate a radiating transponder, such as a pill swallowed by a patient. The system can be triggered to turn on and transmit a waveform to a set of antennas attached to, coupled with, or near the patient. The magnetic field emitted by the transponder can be measured by the receiving antennas, for example, using principles of mutual inductance. The differential phase and/or time shifts between the antennas can contain sufficient information to find the location of the transponder and optionally its orientation relative to body coordinates. The system can display the location and/or orientation of the transponder. Further, the pill can include a reservoir to deliver a payload at a particular site of the patient's body based at least in part on the determined location.

1 .- 20 . (canceled) 
     
     
         21 . A method of locating and triggering a patient-swallowed pill transmitter, the method comprising:
 under control of a hardware system comprising a hardware processor, memory, and a display:
 receiving signals from a plurality of antennas disposed about a body of a patient, the signals responsive to a transmitted signal from a pill transmitter swallowed by the patient; 
 identifying phase differences of the received signals based at least partly on mutual inductance between the pill transmitter and at least some of the plurality of antennas; 
 comparing the phase differences with a stored training set, wherein the stored training set comprises measurements of phase measurements of a pill transmitting outside of the patient at various selected locations in a volume surrounded by the plurality of antennas, wherein the plurality of antennas are positioned on a frame to approximately correspond to locations of the plurality of antennas on the body of the patient; and 
 determining an initial estimate of a location of the pill transmitter within the body of the patient based at least in part on of the comparison of the phase differences with the stored training set and the locations of all the plurality of antennas; and 
 refining the initial estimate by applying a nonlinear process to the initial estimate to produce a refined estimate of the location of the pill transmitter. 
   
     
     
         22 . The method of  claim 21 , further comprising determining locations of all of the plurality of antennas disposed about the body of the patient, wherein the locations of all of the plurality of antennas may change as the patient moves. 
     
     
         23 . The method of  claim 21 , further comprising:
 receiving, from a user interface of the display, a user input indicating a first target location in the patient's body to deliver a medication; and   comparing said refined estimate of the location of the pill transmitter with the first target location.   
     
     
         24 . The method of  claim 21 , further comprising wirelessly sending a trigger signal to the pill transmitter based on said comparing, the trigger signal configured to cause the pill to deliver the medication responsive to receiving the trigger signal. 
     
     
         25 . The method of  claim 21 , wherein the initial estimate takes into account an orientation of the pill transmitter with respect to at least some of the plurality of antennas. 
     
     
         26 . The method of  claim 21 , further comprising filtering the nonlinear estimate of the location of the pill transmitter to produce an overall estimate of the location of the pill transmitter based at least in part on a previously estimated location of the pill transmitter within the body of the patient. 
     
     
         27 . The method of  claim 21 , further comprising outputting an indication of the refined estimate of the location of the pill transmitter for presentation to a clinician. 
     
     
         28 . The method of  claim 21 , wherein the pill comprises a reservoir configured to store a quantity of a drug. 
     
     
         29 . The method of  claim 21 , further comprising activating a feature of the pill separate from medication delivery based in part on the trigger signal.