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 - 22 . (canceled)
23 . An implant system for evaluating a temperature related physical parameter at a target tissue, comprising:
an untethered passive resonant circuit containing sensor with an inductance defining core component having a relative permeability characteristic, exhibiting a drop in relative permeability toward a unity value at a Curie temperature transition occurring within a temperature range ΔT c , said circuit being responsive to a transient applied electromagnetic field to resonate at a predetermined resonant center frequency at temperatures below said temperature range, ΔT c and exhibiting a diminution of the intensity of said response at said resonant center frequency in correspondence with said Curie transition range.
24 . The implant system of claim 23 in which said sensor exhibits an absence of said response at said predetermined resonant center frequency at said Curie temperature.
25 . The implant system of claim 23 in which said sensor has an externally disposed surface coated with a biocompatible conformal layer.
26 . The implant system of claim 23 further comprising at least one tissue engaging implement fixed to and extending outwardly from said sensor and effective to engage tissue in adjacency therewith when implanted.
27 . The implant system of claim 23 in which said implant system further comprises:
a heater component in heat exchange relationship with said sensor and dimensioned with said sensor to effect a minimally invasive implantation at said target tissue.
28 . The implant system of claim 23 further comprising a thermally activatable release agent coating extending over said sensor and effective to dispense said agent at the situs of said target tissue when said target tissue is substantially at said predetermined temperature.
29 . The implant system of claim 27 in which said heater component is separate from said sensor and is configured for implantation within said target tissue in spaced relationship with said sensor.
30 . The implant system of claim 29 in which the surface of said heater component supports a thermally activatable release agent coating effective to disperse at the situs of said target tissue when said heater component is at a temperature generally corresponding with said predetermined temperature.
31 . The implant system of claim 29 in which said heater component is formed of a non-magnetic metal.
32 . The implant system of claim 29 in which said heater component is formed of ultrasound absorptive material.
33 . The implant system of claim 29 in which said heater component further comprises at least one tissue engaging implement fixed to and extending outwardly therefrom and effective to engage tissue in adjacency therewith when implanted.
34 . The implant system of claim 23 in which said sensor further comprises a ferrite inductive core component exhibiting a said Curie transition within said temperature range, an inductive winding with turns wound about said core, and a capacitor coupled to define said resonant circuit with said inductive winding.
35 . The implant system of claim 23 , further comprising:
a non-magnetic stent having a generally cylindrical configuration with an outer surface and central axis, expandable generally diametrically from an insertion diameter to luminally engage a blood vessel and formed of a material heatable from a remote, extra body heating assembly; and
at least one said sensor is coupled in thermal exchange relationship with said stent.
36 . The implant system of claim 35 in which:
a first said sensor exhibits a first said predetermined resonant center frequency at monitor temperatures below a first said temperature range, ΔT c1 ; and
a second said sensor exhibits a second said predetermined resonant center frequency different from said first predetermined resonant center frequency at monitor temperatures below a second said temperature range, ΔT c2 above said first temperature range.
37 . The implant system of claim 35 in which:
said at least one sensor component is fixed to said stent outer surface.
38 . The implant system of claim 37 further comprising:
a non-magnetic flexible band agalvanic with respect to said stent and surmounting said stent outer surface and said sensor, said band being generally diametrically expandable with said stent.
39 . The implant system of claim 37 further comprising:
a thermally activatable release agent layer supported by said stent and effective to disperse when said stent is at a temperature below or generally corresponding with said temperature range, ΔT c .
40 - 65 . (canceled)
66 . An implant system for evaluating a temperature related physical parameter at a target tissue, comprising:
an untethered passive resonant circuit containing sensor with an inductor component and a capacitor component configured as a resonant circuit, said capacitor component and/or said inductor component exhibiting respective capacitance value or values and/or inductance value or values corresponding with a temperature of said target tissue, said circuit being responsive to a transient applied electromagnetic field to resonate at predetermined resonant frequencies corresponding with said temperature or temperatures.
67 . The implant system of claim 66 in which:
said sensor has an externally disposed surface coated with a biocompatible conformal layer.
68 . The implant system of claim 66 further comprising:
at least one tissue engaging implement fixed to and extending outwardly from said sensor and effective to engage tissue in adjacency therewith when implanted.
69 . The implant system of claim 66 in which said implant system further comprises:
a heater component in heat exchange relationship with said sensor and dimensioned with said sensor to effect a minimally invasive implantation at said target tissue.
70 . The implant system of claim 66 further comprising:
a thermally activatable release agent coating extending over said sensor and effective to disperse said agent at the situs of said target tissue.
71 . The implant system of claim 69 in which said heater component is separate from said sensor and is configured for implantation within said target tissue in spaced relationship with said sensor.
72 . The implant system of claim 71 in which the surface of said heater component supports a thermally activatable release agent coating effective to disperse at the situs of said target tissue when said heater component is at a temperature generally corresponding with said predetermined temperature.
73 . The implant system of claim 71 in which said heater component is formed of a non-magnetic metal.
74 . The implant system of claim 71 in which said heater component is formed of ultrasound absorptive material.
75 . The implant system of claim 71 in which said heater component further comprises at least one tissue engaging implement fixed to and extending outwardly therefrom and effective to engage tissue in adjacency therewith when implanted.
76 . The implant system of claim 66 in which said sensor capacitor component exhibits capacitance values varying with temperature to effect a corresponding variation of said resonant frequencies.
77 - 134 . (canceled)
135 . An implant for employment in developing a thermotherapy set point temperature at a target tissue when disposed in thermal exchange therewith, comprising:
an untethered passive resonant circuit with an inductance defining core component formulated with oxides of Fe, Mn and Zn to exhibit a Curie point temperature corresponding with said set point temperature, said circuit being responsive to a transient applied electromagnetic field to resonate at a predetermined resonant center frequency at temperatures below said set point temperature.
136 . The implant of claim 135 in which:
said core component further comprises an oxide of CA in an amount effective to provide a core component resistivity greater than about 100 ohm-cm.
137 . The system of claim 135 in which:
said core component further comprises an oxide of CA in an amount effective to provide a core component resistivity greater than about 500 ohm-cm.
138 . The system of claim 135 in which:
said core component further comprises an oxide of CA in an amount effective to provide a core component resistivity greater than about 700 ohm-cm.
139 - 150 . (canceled)
151 . The system of claim 23 in which:
said physical parameter is the induction of apoptosis of said target tissue.
152 . The system of claim 23 in which:
said physical parameter is the induction of necrosis in said target tissue.
153 . The system of claim 23 in which:
said temperature of said target tissue is within a range from about 39° C. to about 70° C.
154 . The system of claim 23 in which:
said temperature of said target tissue is within a range from about 41° C. to about 50° C.
155 . The system of claim 23 in which:
said temperature of said target tissue is within a range from about 42° C. to about 45° C.
156 . The system of claim 23 in which:
said temperature of said target tissue is within a range from about 4° C. to about 13° C. over normal body temperature.
157 . The system of claim 23 in which:
said temperature of said target tissue is within a range from about 2° C. to about 33° C. over normal body temperature.
158 . The system of claim 23 wherein the target tissue is a neoplasm.
159 . The system of claim 23 wherein the target tissue is a tumor.
160 - 170 . (canceled)
171 . The system of claim 66 in which:
said physical parameter is carrying out an enhancement of apoptosis in said target tissue.
172 . The system of claim 66 in which:
said physical parameter is carrying out an enhancement of necrosis in said target tissue.
173 . The system of claim 66 in which:
said temperature of said target tissue is within a range from about 39° C. to about 70° C.
174 . The system of claim 66 in which:
said temperature of said target tissue is within a range from about 41° C. to about 50° C.
175 . The system of claim 66 in which:
said temperature of said target tissue is within a range from about 42° C. to about 45° C.
176 . The system of claim 66 in which:
said temperature of said target tissue is within a range from about 4° C. to about 13° C. over normal body temperature.
177 . The system of claim 66 in which:
said temperature of said target tissue is within a range from about 2° C. to about 33° C. over normal body temperature.
178 . The system of claim 66 wherein the target tissue is a neoplasm.
179 . The system of claim 66 wherein the target tissue is a tumor.
180 - 217 . (canceled)