US 8,264,342 B2 · Method and apparatus to detect transponder tagged objects, for example during medical procedures

Abstract

The presence or absence of objects (e.g., medical implements, medical supplies) tagged with transponders may be determined in an environment in which medical procedures (e.g., surgery) are performed via an interrogation and detection system which includes a controller and a plurality of antennas positioned along a patient support structure. The antennas may, for example, be positioned along an operating table, bed, a mattress or pad or a sheet and may be radiolucent. Respective antennas may successively be activated to transmit interrogation signals. Multiple antennas may be monitored for responses from transponders to the interrogation signals. For example, all antennas other than the antenna that transmitted the most recent interrogation signal may be monitored.

Claims45

Dependent claims

An apparatus to detect transponder tagged objects which are used in performing medical procedures, the apparatus comprising:

a plurality of antennas, at least some of the antennas spaced at intervals along at least a portion of a length of a patient support structure that is sized to support a patient;
and
a control system communicatively coupled to the antennas and configured to successively transmit an interrogation signal via respective ones of at least two of the antennas and to monitor at least the other ones of the antennas for a response to the interrogation signal in a period following the transmission of the interrogation signal and preceding a transmission of another interrogation signal,
wherein the control system is configured to successively transmit an interrogation signal from all of the antennas in the plurality of antennas, one at a time, and to monitor all of the antennas in the plurality of antennas for a response to each of the interrogation signal except the antenna from which a most recent interrogation signal was transmitted.

1 more element

An apparatus to detect transponder tagged objects which are used in performing medical procedures, the apparatus comprising:

a plurality of antennas, at least some of the antennas spaced at intervals along at least a portion of a length of a patient support structure that is sized to support a patient;
and
a control system communicatively coupled to the antennas and configured to successively transmit an interrogation signal via respective one of a least two of the antennas and to monitor at least the other ones of the antennas for a response to the interrogation signal in a period following the transmission of the interrogation signal and presiding a transmission of another interrogation signal,
wherein the control system is configured to perform a cycle of transponder detection and to measure a level of ambient noise detected via a plurality of antennas during a noise detection portion of the cycle, the noise detection portion temporally spaced from any preceding interrogation portions of the cycle such that transponders, if any, are not responding to any electromagnetic interrogation signals transmitted during any preceding interrogation portions of the cycle;
determine a set of noise cancellation factors for each of a number of antenna channels;
determine a sample averaging time for sampling noise based on the measured level of ambient noise;
determine a sample averaging time for sampling responses to interrogation signals based on the measured level of ambient noise;
average noise corrected samples of noise sampled for the determined noise sample averaging time during the noise detection portion of the cycle;
transmit a number of electromagnetic interrogation signals via one of the antennas during an interrogation portion of the cycle that follows the noise detection portion;
average noise corrected samples of responses sampled for the determined signal averaging time during the interrogation portion of the cycle in a period while no electromagnetic interrogation signals are being transmitted by any of the antennas, the period spaced temporally sufficiently closely to the transmission of the electromagnetic interrogation signals that the transponders, if any, are still responding to the electromagnetic interrogation signals;
and compare averaged noise corrected samples of responses to the interrogation signals to at least one transponder detection threshold.

8 more elements

A method to detect transponder tagged objects which are used during medical procedures, the method comprising:

for each of at least three antennas spaced at intervals along at least a portion of a length of a patient support structure,
successively transmitting a number of interrogation signals via respective ones of the antennas;
monitoring at least the other ones of the antennas for a response to the interrogation signals in a period following the transmission of the interrogation signal and before transmitting another number of interrogation signal via a next one of the antennas;
measuring a level of ambient noise detected via a plurality of the antennas during a noise detection portion of a cycle, the noise detection portion temporally spaced from any preceding interrogation portions of the cycle such that transponders, if any, are not responding to any electromagnetic interrogation signals transmitted during any preceding interrogation portions of the cycle;
determining a set of noise cancellation factors for each of a number of antenna channels;
determining a sample averaging time for sampling noise based on the measured level of ambient noise;
determining a sample averaging time for sampling responses to interrogation signals based on the measured level of ambient noise;
averaging noise corrected samples of noise sampled for the determined noise sample averaging time during the noise detection portion of the cycle;
and
wherein successively transmitting a number of interrogation signals via respective ones of the antennas includes transmitting the number of electromagnetic interrogation signals via one of the antennas during an interrogation portion of the cycle that follows the noise detection portion;
and
monitoring at least the other ones of the antennas for a response to the interrogation signals in a period following transmission of the interrogation signal includes averaging noise corrected samples of responses sampled for the determined signal averaging time during the interrogation portion of the cycle in a period while no electromagnetic interrogation signals are being transmitted by any of the antennas, the period spaced temporally sufficiently closely to the transmission of the electromagnetic interrogation signals that the transponders, if any, are still responding to the electromagnetic interrogation signals.

9 more elements

A system comprising:

a transponder tag coupled to a medical supply item, the transponder tag configured to wirelessly receive electromagnetic energy in the form of a number of interrogation signals and to emit a response to the interrogation signal by radiating electromagnetic energy;
an array of antennas located in a medical procedure environment in which medical procedures are performed;
and
a controller communicatively coupled to the array of antennas and configured to perform a transponder detection cycle that includes a number of noise detection portions and a number of interrogation portions temporally spaced from the noise detection portions, during which the controller:
monitors at least two of the antennas of the array of antennas for an ambient noise in the medical procedure environment during the noise detection portions of the transponder detection cycle, the noise detection portions spaced sufficiently from the interrogation portions that the transponder is not emitting a response detectable by the controller to any previous interrogation signals;
emits a number of interrogation signals from each of at least two of the antennas of the array of antennas, successively, during a number of transmission periods of the interrogation portions of the transponder detection cycle;
and
monitors at least two antennas for any responses to the interrogation signals during a number of detection periods of the interrogation portions of the transponder detection cycle, the detection periods following respective ones of the transmission periods sufficiently closely in time that the transponder is still emitting a response to the interrogation signals by all of the antennas in the array except the one that emitted the most recent signal.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus to detect transponder tagged objects, for example during medical procedures

Life of this patent

Method and apparatus to detect transponder tagged objects, for example during medical procedures

Life of this patent

Abstract

Claims45