1. Field of the Invention
The present invention relates to RFID systems for use with device logistics (such as, but not limited to, medical equipment), and, more particularly, to methods of operating RFID readers used in such systems.
2. Description of the Related Art
Radio frequency identification (RFID) tags are well known throughout industry, and are being increasingly utilized for supply chain management, inventory management, and logistic control. These tags can be written to and read from a handheld transceiver or fixed portal. Small low frequency tags are currently being utilized in surgical tools and implantable devices.
What is needed in the art is a method to determine, using an RFID reader, when a device including an RFID tag is likely located in a desired read zone.
The present invention provides a method to determine, using an RFID reader, when a device including an RFID tag is likely located in a desired read zone.
The invention in one form is directed to a method of operating a Radio Frequency Identification (RFID) reader used in an RFID system for use with a device. The method includes the steps of: providing that the RFID system includes the RFID reader and an RFID tag, the RFID tag being attached to the device; controlling dynamically the RFID reader; monitoring constantly a plurality of outputs of the RFID reader; and determining, dependent on the steps of controlling and monitoring, whether the RFID reader senses the RFID tag in an actual location of the RFID tag.
The invention in another form is directed to a locating system including a device and a Radio Frequency Identification (RFID) system including an RFID reader and an RFID tag. The RFID tag is attached to the device. The RFID reader is configured for providing a plurality of outputs, for being controlled dynamically, for monitoring constantly the plurality of outputs of the RFID reader, and for thereby determining whether the RFID reader senses the RFID tag in an actual location of the RFID tag.
An advantage of the present invention is that it lessens missed reads, such as when RFID tags are so close to a carbon fiber treatment table that the RFID reader may not sense the presence of the RFID tag on the carbon fiber treatment table.
Another advantage of the present invention is that it lessens extra reads, such as when RFID tags which are not on the treatment table (i.e., by way of a medical device which includes the RFID tag) are sometimes sensed by the RFID reader.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring now to the drawings, there is shown schematically a locating system 10 which generally includes a device 12 and a Radio Frequency Identification (RFID) system 14. RFID system 14 includes an RFID reader 16 and an RFID tag 18. RFID tag 18 is attached to device 12.
The description below describes the present invention with reference to a specific environment. However, it is understood that the present invention applies just as well to other environments. Stated another way, the present invention applies to a range of scenarios and is not limited to the RF (radio frequency) suite application. For instance, the description below uses the following terminology: medical device 12; treatment table 20 (such as a carbon fiber treatment table 20); carbon fiber; a radiation oncology device; medical patient; patient; treatment vault; and table. It is understood that this terminology is not to be considered limiting, but is used merely by way of example. Thus, the present invention applies to devices, not only to medical devices 12 or to radiation oncology devices; thus, reference number 12 also applies to devices generally. Further, the present invention applies to a desired read zone (the zone which it is desired that RFID reader 16 reads), not only to a table, or a treatment table 20, or a carbon fiber treatment table 20; thus, reference number 20 also applies to a desired read zone. Further, the present invention applies to an RF-reflecting environment (radio frequency reflecting environment) and also to an RF-absorbing environment (radio frequency absorbing environment), not only to a carbon fiber environment (as with carbon fiber treatment table 20); thus, the reference number 20 can also apply not just to a desired read zone but also to a desired read zone having an RF-reflecting environment or an RF-absorbing environment. Thus, the present invention can also apply to a desired read zone 20 including a ferrous environment or generally a metallic environment (i.e., metallic objects). Further, the present invention applies to persons generally (in a variety of contexts), not only to patients or medical patients. Further, the present invention applies to environments generally (to a variety of environments), not only to treatment vaults.
It has been found that, when reading RFID tags on a radiation oncology device in a treatment vault using conventional RFID readers, the following problems may occur: (1) tags which are too close to the carbon fiber treatment table are sometimes not read; and (2) tags which are not on the treatment table are sometimes read. Traditionally, the reader power and sensitivity are set at medium levels to capture a large number of difficult reads, while not creating so much stray RF (radio frequency) as to read tags not on the table. This static, medium setting is a compromise, which may lead to missed reads and extra reads.
By contrast, in summary, the present invention uses dynamic control of RFID reader 16 and constant monitoring of the output to more successfully determine whether RFID tag 18 is seen in its actual location. Basically, RFID reader 16 power and sensitivity settings oscillate from high to low output and the number of reads are counted. At high power, RFID reader 16 will see everything on the treatment table 20 (such as the carbon fiber treatment table 20 mentioned above), including RFID tags 18 very close to the carbon fiber treatment table 20. Unfortunately, RFID reader 16 will also see items not on table 20. To filter these unwanted reads out of the data set, the power of RFID reader 16 will then be set to medium. At medium power, even RFID tags 18 too close to carbon fiber table 20 will be seen more than items (such as medical device 12 with an RFID tag 18) off carbon fiber treatment table 20. These readings would be added to the data set. At low power, the items (a medical device 12 with an RFID tag 18) not on the table 20 will disappear from the reader 16. It can then be inferred that these items 12, 18 were not on carbon fiber treatment table 20.
RFID reader 16 of the present invention is configured for providing a plurality of outputs, is configured for being controlled dynamically, is configured for monitoring constantly the outputs of RFID reader 16, and is thereby configured for determining whether RFID reader 16 senses RFID tag 18 in an actual location of RFID tag 18. Stated another way, RFID reader 16 of the present invention is configured for determining whether RFID tag 18 (and thus also medical device 12 to which RFID tag 18 is attached) is actually located on carbon fiber treatment table 20 or is not actually located on carbon fiber treatment table 20. In making this determination (whether RFID tag 18 is or is not actually on carbon fiber treatment table 20), RFID reader 16 is configured for oscillating the power setting of RFID reader 16 between high power, medium power, and low power of RFID reader 16. In oscillating between high power, medium power, and low power, RFID reader 16 takes at least three reads. RFID reader 16 is configured for counting and thus tracking a plurality of reads. These plurality of reads include a first read, a second read, and a third read, the first read occurring at high power of RFID reader 16, the second read occurring at medium power of RFID reader 16, and third read occurring at low power of RFID reader 16. Each one of the outputs of RFID reader 16 corresponds to a respective one of the reads. In other words, each read (one occurring at high power, one read occurring at medium power, and one read occurring at low power) produces an output, each output of each read including (a) RFID tag 18 is sensed by RFID reader 16, or (b) RFID tag 18 is not sensed by RFID reader 16. Each of these outputs from the reads is used by RFID reader 16 to determine whether or not RFID tag 18 (and thus also medical device 12 to which RFID tag 18 is attached) is actually located on carbon fiber treatment table 20. Thus, RFID reader 16 is configured for evaluating each of the plurality of outputs from the plurality of reads and thereby for filtering out when medical device 12 along with its RFID tag 18 are not actually located on carbon fiber treatment table 20 so as to determine that medical device 12 along with its RFID tag 18 are likely on carbon fiber treatment table 20 only when medical device 12 along with its RFID tag 18 are actually on carbon fiber treatment table 20. The operation of RFID reader 16 in connection with medical device 12, RFID tag 18, and carbon fiber treatment table 20 is shown in
The present invention further provides a method of operating a RFID reader 16 used in RFID system 14 for use with medical device 12, the method including the steps of: providing that RFID system 14 includes RFID reader 16 and an RFID tag 18, RFID tag 18 being attached to medical device 12; controlling dynamically RFID reader 16; monitoring constantly a plurality of outputs of RFID reader 16; and determining, dependent on the steps of controlling and monitoring, whether RFID reader 16 senses RFID tag 18 in an actual location of RFID tag 18. The step of controlling includes oscillating a power setting of RFID reader 16 between a high power, a medium power, and a low power. The step of controlling includes counting a plurality of reads. The plurality of reads includes a first read, a second read, and a third read, the first read occurring at high power, the second read occurring at medium power, and the third read occurring at low power. Each one of the plurality of outputs corresponds to a respective one of the plurality of reads, each output of each read including (a) RFID tag 18 is sensed by RFID reader 16, or (b) RFID tag 18 is not sensed by RFID reader 16. The step of determining includes evaluating each of the plurality of outputs from the plurality of reads and thereby filtering out when medical device 12 along with its RFID tag 18 are not actually located on carbon fiber treatment table 20 so as to determine that medical device 12 along with its RFID tag 18 are likely on carbon fiber treatment table 20 only when medical device 12 along with its RFID tag 18 are actually on carbon fiber treatment table 20.
Conditions 1-3 of
Conditions 4-6 of
Conditions 7-9 of
In use, a medical patient can be placed on treatment table 20. RFID reader 16 can then be used to sense whether or not an RFID tag 18 (attached to a medical device 12) is present relative to patient. To make this determination, RFID reader 16 takes a plurality of readings at different power settings, as discussed above.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/260,986, entitled “METHOD OF OPERATING AN RFID READER IN AN RFID SYSTEM”, filed Nov. 13, 2009, which is incorporated herein by reference.
Number | Date | Country | |
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61260986 | Nov 2009 | US |