Locating an implanted object based on external antenna loading
First Claim
1. A system comprising:
- an external antenna;
an external device coupled to the external antenna that generates a first waveform, drives the external antenna with the first waveform while the external antenna is moved through a three-dimensional region proximate to an implantable object a first time, periodically measures values of an electrical parameter associated with the external antenna while the external antenna is moved through the three-dimensional region the first time and driven with the first waveform, generates a second waveform that has at least one different waveform parameter than the first waveform, drives the external antenna with the second waveform while the external antenna is moved through the three-dimensional region a second time, and periodically measures values of the electrical parameter while the external antenna is moved through the three-dimensional region the second time and driven with the second waveform; and
a processor that determines a first position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the first waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured, determines a second position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the second waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured, and determines first and second equations based on the first and second position/electrical parameter relationships,wherein the first equation defines a first position variable as a function of the electrical parameter and the second equation defines a second position variable as a function of the electrical parameter.
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Abstract
In general, the invention is directed to techniques for locating an implanted object using an external antenna. The implanted object may be, for example, an internal antenna that facilitates recharging of and/or communication with an implantable medical device. An external device coupled to the external antenna drives the antenna with a plurality of waveforms. Asymmetry in the loading profile of the external antenna when it is driven by the plurality of waveforms allows the external device or another device to determine the location of the implanted object relative to the external antenna. The external device or other device may provide information to a user based on the determined location of the implanted object relative to the external antenna, such as information to help a user position the external antenna with respect to an internal antenna in embodiments in which the implanted object is an internal antenna.
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Citations
12 Claims
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1. A system comprising:
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an external antenna; an external device coupled to the external antenna that generates a first waveform, drives the external antenna with the first waveform while the external antenna is moved through a three-dimensional region proximate to an implantable object a first time, periodically measures values of an electrical parameter associated with the external antenna while the external antenna is moved through the three-dimensional region the first time and driven with the first waveform, generates a second waveform that has at least one different waveform parameter than the first waveform, drives the external antenna with the second waveform while the external antenna is moved through the three-dimensional region a second time, and periodically measures values of the electrical parameter while the external antenna is moved through the three-dimensional region the second time and driven with the second waveform; and a processor that determines a first position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the first waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured, determines a second position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the second waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured, and determines first and second equations based on the first and second position/electrical parameter relationships, wherein the first equation defines a first position variable as a function of the electrical parameter and the second equation defines a second position variable as a function of the electrical parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A non-transitory computer-readable medium comprising instructions that cause a programmable processor to:
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control generation of a first waveform in an external device to drive an external antenna while the external antenna is moved through a three-dimensional region proximate to an implantable object a first time; periodically measure values of an electrical parameter associated with the external antenna while the external antenna is moved through the three-dimensional region the first time and driven with the first waveform; determine a first position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the first waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured; control generation of a second waveform in the external device to drive the external antenna while the external antenna is moved through the three-dimensional region a second time, wherein the second waveform has at least one different waveform parameter than the first waveform; periodically measure values of the electrical parameter while the external antenna is moved through the three-dimensional region the second time and driven with the second waveform; determine a second position/electrical parameter relationship based on the electrical parameter values measured while the external antenna was driven with the second waveform and positions within the three-dimensional region at which the external antenna was located when the electrical parameter values were measured; and determine first and second equations based on the first and second position/electrical parameter relationships, wherein the first equation defines a first position variable as a function of the electrical parameter, and the second equation defines a second position variable as a function of the electrical parameter. - View Dependent Claims (10, 11, 12)
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Specification