System, method and apparatus for evaluating tissue temperature
Method, system and apparatus for monitoring target tissue temperatures wherein temperature sensors are configured as passive resonant circuits each with a unique resonating signature at monitoring temperatures extending below a select temperature setpoint. The resonant circuits are configured with an inductor component formed of windings about a ferrite core having a Curie temperature characteristic corresponding with a desired temperature setpoint. By selecting inductor winding turns and capacitance values, unique resonant center frequencies are detectable. Temperature monitoring can be carried out with implants at lower threshold and upper limit temperature responses. Additionally, the lower threshold sensors may be combined with auto-regulated heater implants having Curie transitions at upper temperature limits.
1 - 103 . (canceled)
104 . Stent apparatus for positioning within the body of a patient, comprising:
a metal stent structure having a contact surface configured for abutting engagement with tissue of said patient and formed with material responsive to energy non-invasively applied from an extra-body source to elevate in temperature; and
a first passive resonant sensor attached to said stent structure having an electromagnetic response to an extra body applied interrogational electromagnetic field at monitor temperatures.
105 . The stent apparatus of claim 104 further comprising:
a second passive resonant sensor attached to said stent structure having an electromagnetic response to an extra-body applied interrogational electromagnetic field when at monitor temperatures.
106 . The stent apparatus of claim 104 in which:
said first passive resonant sensor is responsive to said interrogational electromagnetic field at a first resonant center frequency when at said monitor temperatures and exhibits a decrease in the intensity of said response at said first resonant center frequency when at temperatures approaching a hyperthermia based first target temperature.
107 . The stent apparatus of claim 104 in which:
said first passive resonant sensor is responsive to said interrogational electromagnetic field at a first resonant center frequency when at said monitor temperatures and exhibits an absence of said response at said first resonant center frequency when at a hyperthermia based first target temperature.
108 . The stent apparatus of claim 104 in which:
said second passive resonant sensor is responsive to said interrogational electromagnetic field at a second resonant center frequency when at said monitor temperatures and exhibits a decrease in the intensity of said response at said second resonant center frequency when at temperatures approaching a hyperthermia based second target temperature.
109 . The stent apparatus of claim 105 in which:
said second passive resonant sensor is responsive to said interrogational electromagnetic field at a second resonant center frequency when at said monitor temperatures and exhibits an absence of said response at said second resonant center frequency when at a hyperthermia based second target temperature.
110 . The stent apparatus of claim 105 in which:
said first passive resonant sensor is attached to said metal stent structure contact surface.
111 . The stent apparatus of claim 110 in which:
said second passive resonant sensor is attached to said stent structure contact surface.
112 . The stent apparatus of claim 106 in which:
said second passive resonant sensor is responsive to said interrogational electromagnetic field at a second resonant center frequency when at said monitor temperatures and exhibits a decrease in the intensity of said response at said second resonant center frequency when at a temperature approaching a hyperthermia based second target temperature.
113 . The stent apparatus of claim 107 in which:
said second passive resonant sensor is responsive to said interrogational electromagnetic field at a second resonant center frequency when at said monitor temperatures and exhibits an absence of said response at said second resonant center frequency when at a hyperthermia based second target temperature.
114 . The stent apparatus of claim 113 in which:
said first passive resonant sensor is configured to exhibit said decrease in the intensity of said response when at temperatures approaching a lower threshold first said target temperature and
said second passive resonant sensor is configured to exhibit said decrease in the intensity of said response when at temperatures approaching an upper limit second said target temperature.
115 . The stent apparatus of claim 113 in which:
said first passive resonant sensor is configured to exhibit said absence of said response at said first resonant center frequency when at a lower threshold first said target temperature; and
said second passive resonant sensor is configured to exhibit said absence of said response at said second resonant center frequency when at an upper limit second said target temperature.
116 . The stent apparatus of claim 110 further comprising:
a flexible securement band agalvanic with respect to said metal stent structure and tensionally surmounting said metal stent structure and said first sensor.
117 . The stent apparatus of claim 111 further comprising:
a flexible securement band agalvanic with respect to said metal stent structure and tensionally surmounting said metal stent structure and said second sensor.
118 . The stent apparatus of claim 104 further comprising:
a thermally activatable release agent coating extending within said metal stent structure, effective to limit restenosis when dispersed at said hyperthermia based temperature level.
119 - 217 . (canceled)