System and method for locating an internal device in a closed system

• US 20070027505A1
• Filed: 07/29/2005
• Published: 02/01/2007
• Est. Priority Date: 07/29/2005
• Status: Active Grant

• Current Assignee: Medos International Sarl (Johnson & Johnson)
• Original Assignee: Codman Neuro Sciences Sarl
• Inventors: Ginggen, Alec
• Granted Patent: US 8,186,358 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/062 using magnetic field
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 2209/045 for filling, e.g. for filling reservoirs
• CPC Class Codes: A61M 39/0208 Subcutaneous access sites for injecting or removing fluids transcutaneous access sites A61M39/0247; implantable infusion devices A61M5/14276
• CPC Class Codes: A61M 5/14276 specially adapted for implantation

Abstract

A system and method for locating an internal device separated by a boundary from and in wireless communication with an external device. External device includes an active emitter mechanism wherein a carrier signal is modulated by a location interrogation signal thereby generating an external RF power signal during transmission to the internal device. A secondary antenna of the internal device receives the external RF power signal and induces an RF power signal therein that is converted to a DC induced voltage signal. An indication signal proportional to the intensity of the DC induced voltage signal induced in the secondary antenna is produced by the external device. The process is repeated each time the user moves the external device to a new location proximate the patient'"'"'s body until a maximum DC induced voltage signal measurement is ascertained representative of a specific area in which the internal device is located.

Claims

1. A closed system, comprising:

an external device comprising;

a first processor for generating a location interrogation signal;

a first modulator for modulating a carrier signal by the location interrogation signal;

a first antenna for transmitting the modulated location interrogation signal including a substantially constant external RF power signal;

an internal device in wireless communication with the external device, the internal device comprising;

a secondary antenna for receiving the modulated location interrogation signal including the external RF power signal from the external device and inducing an RF power signal therein;

a converter for transforming the induced RF power signal to a DC induced voltage signal;

a second processor for receiving as input the DC induced voltage signal and generating a location data signal including the DC induced voltage signal;

a second modulator for modulating the location data signal prior to wireless transmission by the secondary antenna from the internal device to the external device; and

the first processor receiving as input the modulated location data signal from the internal device and producing an indicator signal proportional to the intensity of the DC induced voltage signal induced in the secondary antenna of the internal device.

2. The system in accordance with claim 1, wherein the internal device is an implantable medical device.

3. The system in accordance with claim 2, wherein the implantable medical device is an implantable drug infusion pump and the secondary antenna is disposed proximate a bolus port.

4. The system in accordance with claim 2, wherein the implantable medical device is an implantable drug infusion pump and the secondary antenna is disposed proximate a refill port.

5. The system in accordance with claim 4, further comprising a tertiary antenna disposed proximate the bolus port.

6. The system in accordance with claim 1, further comprising a speaker for generating an audible tone based on the indicator signal produced by the first processor.

7. The system in accordance with claim 1, further comprising a display for generating a visual display based on the indicator signal produced by the first processor.

8. The system in accordance with claim 1, wherein the internal device does not include an active emitter.

9. The system in accordance with claim 1, further comprising a sampler for receiving as input the DC voltage signal from the converter and producing a digital DC induced voltage signal.

10. The system in accordance with claim 1, wherein the indicator signal is directly proportional or inversely proportional to the intensity of the DC induced voltage signal induced in the secondary antenna of the internal device

11. A method for locating an internal device in a closed system including an external device in wireless communication with the internal device, the external device having an associated primary antenna and the internal device having an associated secondary antenna, comprising the steps of:

(a) positioning the external device at a first location;

(b) modulating a carrier signal by a location interrogation signal;

(c) transmitting wirelessly from the primary antenna of the external device a modulated location interrogation signal including a substantially constant external RF power signal;

(d) detecting an amount of RF power induced in the secondary antenna of the internal device based on the substantially constant external RF power signal in the modulated location interrogation signal emitted by the primary antenna of the external device;

(e) converting the detected RF induced power to a DC induced voltage signal;

(f) generating a location data signal including the DC induced voltage signal;

(g) modulating the location data signal;

(h) transmitting wirelessly from the internal device to the external device the modulated location data signal;

(i) demodulating at the external device the received location detection signal to recover the DC voltage signal;

(j) generating an indicator signal proportional to the intensity of the DC induced voltage signal in the secondary antenna of the internal device; and

(k) positioning the external device at a new location, repeating the steps (b)-(j).

12. The method in accordance with claim 11, wherein the internal device is an implantable medical device.

13. The method in accordance with claim 12, wherein the implantable medical device is a drug infusion pump and the secondary antenna is disposed proximate a bolus port.

14. The method in accordance with claim 12, wherein the implantable medical device is a drug infusion pump and the secondary antenna is disposed proximate a refill port.

15. The method in accordance with claim 11, wherein prior to the step (d), selecting as the secondary antenna of the internal device from one of a bolus port antenna disposed proximate a bolus port and a refill port antenna disposed proximate the refill port to detect the amount of RF power induced therein.

16. The method in accordance with claim 11, wherein the internal device does not include an active emitter.

17. The method in accordance with claim 11, wherein the first location and the new location are both positioned proximate the patient'"'"'s body.

18. The method in accordance with claim 11, wherein in step (j) the indicator signal is directly proportional or inversely proportional to the intensity of the DC induced voltage signal in the secondary antenna of the internal device.

19. A closed system, comprising:

an external device comprising;

a first processor for generating a location interrogation signal;

a first modulator for modulating a carrier signal by the location interrogation signal;

a first antenna for transmitting the modulated location interrogation signal including a substantially constant external RF power signal;

an internal device in wireless communication with the external device, the internal device comprising;

a secondary antenna for receiving the external RF power signal from the external device and inducing an RF power signal therein;

a converter for transforming the induced RF power signal to a DC induced voltage signal;

a second processor for receiving as input the DC induced voltage signal and generating a location data signal including the DC induced voltage signal;

a second modulator for modulating the location data signal prior to wireless transmission by the secondary antenna; and

the first processor receiving as input the location data signal from the internal device and producing an indicator signal based on the comparison of;

(i) a first DC induced voltage signal representative of an amount of induced power received in the secondary antenna in response to a current interrogation location signal triggered by the external device and (ii) a second DC induced voltage signal corresponding to a previous interrogation location signal generated by the external device.

20. The system in accordance with claim 19, wherein the internal device does not include an active emitter.

21. A method for locating an internal device in a closed system including an external device in wireless communication with the internal device, the external device having an associated primary antenna and the internal device having an associated secondary antenna, comprising the steps of:

(a) positioning the external device at a first location;

(b) modulating a carrier signal by a location interrogation signal;

(c) transmitting wirelessly from the primary antenna of the external device a modulated location interrogation signal including a substantially constant external RF power signal;

(d) detecting an amount of RF power induced in the secondary antenna of the internal device based on the substantially constant external RF power signal in the modulated location interrogation signal emitted by the primary antenna of the external device;

(e) converting the detected RF induced power to a DC induced voltage signal;

(f) generating a location data signal including the DC induced voltage signal;

(g) modulating the location data signal;

(h) transmitting wirelessly from the internal device to the external device the modulated location data signal;

(i) demodulating at the external device the received location detection signal to recover the DC voltage signal;

(j) generating an indicator signal based on the comparison of;

(i) a first DC induced voltage signal representative of an amount of induced power received in the secondary antenna in response to a current interrogation location signal triggered by the external device and (ii) a second DC induced voltage signal corresponding to a previous interrogation location signal generated by the external device; and

(k) positioning the external device at a new location, repeating the steps (b)-(j).

22. The method in accordance with claim 21, wherein the internal device does not include an active emitter.