Method and apparatus for radiation effects detection

• US 7,935,936 B2
• Filed: 01/29/2009
• Issued: 05/03/2011
• Est. Priority Date: 01/30/2008
• Status: Expired due to Fees

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Stubbs, Scott R., Stahmann, Jeffrey E., Maile, Keith R., Linder, William J.
• Primary Examiner(s): Porta; David P.
• Assistant Examiner(s): Gaworecki; Mark R
• Application Number:
  US12/361,935
• Publication Number:
  US 20090189082A1
• Time in Patent Office: 824 Days
• Field of Search: 250/370.01, 250/370.07, 250/394, 250/395
• US Class Current: 250/394
• CPC Class Codes: A61N 1/37 Monitoring; Protecting
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents

Abstract

This document discusses, among other things, an implantable apparatus comprising a plurality of solid state electronic circuits disposed at a plurality of different locations in the apparatus, a plurality of ionizing radiation exposure sensors disposed at the different locations and configured to generate an indication of a non-single-event-upset (non-SEU) effect to the solid state electronic circuit from an exposure to ionizing radiation, wherein the ionizing radiation exposure sensors respectively monitor at least two different types of operating parameters of respectively correspondingly located solid state circuits, and a controller circuit communicatively coupled to the ionizing radiation exposure sensors, wherein the controller circuit is configured to quantify the effect to the solid state electronic circuits using the different monitored operating parameters.

Claims

1. An implantable medical apparatus comprising:

a plurality of solid state electronic circuits disposed at a plurality of different locations in the apparatus;

a plurality of ionizing radiation exposure sensors disposed at the different locations and configured to generate an indication of a non-single-event-upset (non-SEU) effect to the correspondingly located solid state electronic circuit from an exposure to ionizing radiation, wherein an ionizing radiation exposure sensor includes at least one circuit structure to detect the exposure to ionizing radiation by monitoring at least one operating parameter of the solid state circuit, and wherein the ionizing radiation exposure sensors respectively monitor at least two different types of operating parameters of respectively correspondingly located solid state circuits; and

a controller circuit communicatively coupled to the ionizing radiation exposure sensors, wherein the controller circuit is configured to quantify the effect to the solid state electronic circuits using the different monitored operating parameters.

2. The apparatus of claim 1, wherein the controller circuit is configured to alter operation of the apparatus according to the indication of the non-SEU effect.

3. The apparatus of claim 1, including:

a plurality of solid state electronic circuits configured to perform different functions at a plurality of different locations in the apparatus; and

wherein the controller circuit is configured to inhibit or deactivate a function of the apparatus when an ionizing radiation exposure sensor indicates a permanent non-SEU effect to the solid state electronic circuit at a location corresponding to the function.

4. The apparatus of claim 1, including a comparison circuit communicatively coupled to an ionizing radiation exposure sensor and the controller circuit, wherein the ionizing radiation exposure sensor includes a test transistor, and wherein the controller circuit is configured to alter operation of the apparatus if the comparison circuit indicates a shift in an operating curve of the test transistor after exposure to radiation.

5. The apparatus of claim 4, wherein the test transistor includes a test field effect transistor (FET), and wherein the comparison circuit is configured to indicate a shift in drain-source current for a specified gate-source voltage applied to the test FET.

6. The apparatus of claim 1, including a comparison circuit communicatively coupled to an ionizing radiation exposure sensor and the controller circuit, wherein the ionizing radiation exposure sensor includes a test junction diode, and wherein the controller circuit is configured to alter operation of the apparatus if the comparison circuit indicates a shift in an operating curve of the test junction diode after exposure to radiation.

7. The apparatus of claim 6, wherein the ionizing radiation exposure sensor includes a test amplifier circuit that includes a bipolar junction transistor, and wherein the comparison circuit is configured to indicate a shift in signal gain of the test amplifier circuit for a specified input signal applied to the amplifier circuit.

8. The apparatus of claim 1, wherein the radiation exposure sensors include at least one of:

a PN junction diode test circuit;

a schottky junction diode test circuit;

an N-channel FET test circuit;

a P-channel FET test circuit;

an NPN bipolar junction transistor test circuit; and

a PNP bipolar junction transistor test circuit.

9. The apparatus of claim 1, wherein an ionizing radiation exposure sensor comprises an accumulated ionizing radiation exposure sensor and is configured to generate the indication of a non-SEU effect to the solid state electronic circuit from the solid state electronic circuit'"'"'s accumulated exposure to ionizing radiation.

10. The apparatus of claim 9, wherein the apparatus includes an ionizing radiation dose rate sensor communicatively coupled to the controller circuit, and wherein the controller circuit is configured to blank the indication from the accumulated ionizing radiation exposure sensor when the radiation dose rate sensor indicates that flux ionizing radiation exceeds a flux ionizing radiation threshold.

11. The apparatus of claim 1, wherein an ionizing radiation exposure sensor is an ionizing radiation dose rate sensor configured to generate the indication of a non-SEU effect to the solid state electronic circuit from the solid state electronic circuit'"'"'s exposure to flux ionizing radiation that exceeds a flux ionizing radiation threshold.

12. The apparatus of claim 11, wherein the apparatus comprises a cardiac function management (CFM) device, and wherein the controller circuit is configured to blank any sensing features of the CFM device when the ionizing radiation dose rate sensor detects high flux ionizing radiation.

13. The apparatus of claim 11, wherein the ionizing radiation dose rate sensor includes at least one of a junction diode or a bipolar junction transistor.

14. The apparatus of claim 1, wherein the apparatus is a CFM device, wherein the controller circuit is configured to, according to the indication of the non-SEU effect, transition the CFM device to a mode that provides pacing therapy to a ventricle when a V-V interval exceeds a specified ventricular interval without timing the pacing of the ventricle from an atrial cardiac event, and that provides pacing therapy without regard to any intrinsic cardiac depolarization event occurring in the ventricle.

15. The apparatus of claim 1, including a read only memory (ROM) communicatively coupled to the controller circuit, and wherein the controller circuit is configured to, according to the indication of the non-SEU effect, transition the apparatus to a mode where the controller circuit only performs program instructions that are included in the ROM.

16. The apparatus of claim 1, including a reset circuit communicatively coupled to the controller circuit, and wherein the controller circuit is configured to initiate a reset to the apparatus according to the indication of the non-SEU effect.

17. The apparatus of claim 1,

wherein a solid state electronic circuit comprises an integrated circuit (IC),

wherein an ionizing radiation exposure sensor is configured to indicate a shift in a first operating parameter of the IC, and

wherein the controller circuit is configured to modify a second operating parameter of the IC to accommodate the shift in the first operating parameter.

18. The apparatus of claim 1, including a plurality of integrated circuits (ICs), each IC including including at least one of the plurality of ionizing radiation exposure sensors communicatively coupled to the controller circuit, and wherein the ICs are fabricated using different IC processes.

19. The apparatus of claim 1, including:

a memory communicatively coupled to the controller circuit and configured to store an indication of the non-SEU effect; and

a communication circuit communicatively coupled to the controller circuit and configured to communicate with an external unit, and wherein the controller circuit is configured to communicate the indication of the non-SEU effect to the external unit.

20. The apparatus of claim 1, wherein the ionizing radiation exposure sensors are disposed with varying orientations to detect exposure to varying orientations of ionizing radiation.

21. The apparatus of claim 1, wherein the implantable medical apparatus is included in at least one of a CFM device, a neural stimulation device, a drug delivery device, or a diagnostic device.

22. The apparatus of claim 1, including a memory communicatively coupled to the controller circuit and configured to store an operating curve value for at least one ionizing radiation exposure sensor circuit, and wherein the controller circuit is configured to quantify the effect of ionizing radiation to a correspondingly located solid state electronic circuit using a comparison of a monitored operating curve value to the stored operating curve value.

23. A method comprising:

detecting exposure of a plurality of solid state electronic circuits disposed at different locations of an implantable medical device to ionizing radiation by respectively monitoring at least two different types of operating parameters of respectively located solid state circuits;

quantifying the effect to the solid state electronic circuits to the ionizing radiation using the different monitored operating parameters; and

generating an indication of a non-single-event-upset (non-SEU) effect to the solid state electronic circuits from the exposure to ionizing radiation.

24. The method of claim 23, wherein detecting exposure to ionizing radiation includes detecting exposure using an accumulated ionizing radiation exposure sensor that generates the indication of a non-SEU effect to the solid state electronic circuit from the solid state electronic circuit'"'"'s accumulated exposure to ionizing radiation.

25. The method of claim 23, wherein detecting exposure to ionizing radiation includes detecting exposure using an ionizing radiation dose rate sensor that generates the indication of a non-SEU effect to the solid state electronic circuit when the solid state electronic circuit is exposed to flux ionizing radiation that exceeds a flux ionizing radiation threshold.

26. The method of claim 23, including communicating historical data regarding a non-SEU effect to an external device.

27. The method of claim 23, including altering operation of the IMD according to the indication of the non-SEU effect to the solid state electronic circuit.