Technical Review

Wasif M Khawaja – ECE 4884 Section L05/Dr Koblasz Group Name Care Takers

Radio-Frequency Identification (RFID) Systems Introduction Radio-Frequency Identification (RFID) has become a valuable business and technology tool replacing existing tracking technologies like the bar code reader. RFID is an automatic identification method, relying on storing and remotely retrieving data using transponders. A transponder is a device that receives, amplifies, and retransmits the signals. Recent advances in Radio Frequency (RF) and microwave systems have allowed RFID technology to be used in many applications worldwide. This paper focuses on RFID tags used to track hospital’s infusion pump inventory and monitor patient’s movements in and out of their rooms. Commercial Applications of RFID The use for RFID tracking and identification system has become mainstream in healthcare industry. The use of RFID technology has served humanity by providing efficient means of surveillance, authentication, access control, patient care, industrial automation, and supply chain integration. Healthcare is the largest and fastest-growing industry worldwide, with a value estimated at over $6 trillion in 2005, and growing at a healthy rate [1]. Seeing this current rate of growth, Emory Healthcare, Georgia's largest health-care system, is using General Electric’s (GE) IntelliMotion RFID asset-tracking system to improve management and utilization of infusion pumps and other high-value equipment. IntelliMotion, which has been approved by ISO 24730 standards [2], uses 2.45 GHz of active RFID tags to monitor patients movements in the hospital.. Introducing RFID in a healthcare system has been a great success because, by reducing human intervention, mistakes can be avoided, which in turn can improve healthcare systems. To pioneer the research in RFID, Georgia Institute of Technology opened a research institute in Ireland with research and collaboration valued at $24 million. The focus of this research lab in Ireland is going to be usage of RFID to track hospital equipment and monitor patient’s movement [3].

Underlying Technology behind RFID System A RFID system consists of a reader and a tag communicating over large distance on a certain frequency, just like radio communication. An RFID reader, also known as interrogator, captures and processes data from a RFID tag in close proximity. RFID tags and readers must be

Technical Review

Wasif M Khawaja – ECE 4884 Section L05/Dr Koblasz Group Name Care Takers

tuned into the same frequency to enable communication [4]. Depending on applications some RFID readers interfaces with a computer to store logs of data to track a patient’s movement. Two types of RFID tags are used in the healthcare system: active and passive. Passive RFID tags have no internal power supply and they only communicate when they are close to RFID readers. An active RFID tag has its own battery to communicate over distances greater than five feet. The communication distance of passive RFID depends on the size of the antenna in the tag, whereas in active RFID tags, communication distance is dependent on the size of the battery it uses. Active tags are mostly used in areas of high interference such as hospitals where different radio wave communications are taking place. Battery-operated RFID systems used in most hospitals (at 850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer transmission ranges of more than 100 feet, with wavelengths in the 2.4 GHz range [5]. The antenna inside an RFID tag is nothing more than a coil of wire connected to an integrated circuit (IC) chip. When the tag is brought in close proximity to an RFID reader, the electromagnetic field produced by the reader induces a current in the coil of the RFID reader due to principle known as Ampere’s Law [5]. The integrated circuit chip receives this current and sends out a signal at a particular frequency giving away IC chip information, which can be detected and recorded by the active RFID reader. A patient’s movement in the hospital can be tracked and logged into the system using passive RFID detection method. Building blocks of RFID systems in Healthcare The smallest RFID chip, developed by Hitachi Corporation, measures 0.15x0.15mm and is 7.5 micrometer thin. Hitachi's current model on the market measures 0.4x0.4mm and is being used in biomedical applications on a millimeter scale. The new RFID chips have a 128-bit ROM for storing a unique 38 digit number. Hitachi uses semiconductor miniaturization technology and electron beams to write data on the chip substrates to achieve the new, smaller size [6]. Philips Research developed world's first 13.56 MHz RFID tag based on plastic electronics. These tags are used in most hospitals for monitoring a patient’s movement [7]. Plastic RFID tags can be temporarily grafted into a patient’s skin for the time they are in hospital to monitor them remotely through the Wi-Fi network. One application of RFID tracking in patient care is to notify the nurse when patients leave their room. This notification can be implemented by tagging the patient with an RFID tag and installing a small reader next to the

Technical Review

Wasif M Khawaja – ECE 4884 Section L05/Dr Koblasz Group Name Care Takers

door. Patients with RFID tags can be prevented from falling off their beds by monitoring the RFID tag distance from the tag reader. If the distance between the tag and the reader remains close for more than a minute, an alarm can be programmed to sound to notify the hospital management. Two French companies, Coronis Systems and Data Health System S.A. (DHS), have combined their technologies to create a wireless system that can alert healthcare workers when a patient falls [8]. Phidget sells inexpensive RFID readers that cost approximately $60 and multidirectional RFID tags for $2 that operate at a relatively low frequency range of 125 to 140 KHz and has a range of 3” [9].

Technical Review

Wasif M Khawaja – ECE 4884 Section L05/Dr Koblasz Group Name Care Takers

References

[1]

A. Lewcock, “RFID set for explosive growth”,’ [Website], 2007 July 26, [ cited 2008 Jan 23], Available HTTP: http://www.in-pharmatechnologist.com/news/ng.asp?id=78551rfid-healthcare-industry-supply-chain-management-counterfeiting

[2]

M. Catherine O'Connor, “Emory Healthcare Tracks Its Pumps,” RFID Journal, [Online Journal], 2007 May 15, [cited 2008 Jan 23], Available HTTP: http://www.rfidjournal.com/article/view/3311/

[3]

Research Institute, “Georgia Tech Opens Research Institute in Ireland,” [Organization Website], [cited 2008 Jan 22], Available HTTP: http://www.gatech.edu/news-room/release.php?id=1021

[4]

B. Manish, RFID Field Guide: Deploying Radio Frequency Identification Systems. Prentice Hall PTR, 2005

[5]

V. ‘Aurora’ Beal, “All About RFID,” [Website], 2005 March 18, [cited 2008 Jan 23], Available HTTP: http://www.webopedia.com/DidYouKnow//Computer_Science /2005/rfid.asp

[6]

Hitachi, “World’s smallest and thinnest 0.15 x 0.15 mm, 7.5um thick RFID IC chip,” [Company Website], 2006 Feb 6, [cited 2008 Jan 23], Available HTTP: http://www.hitachi.com/New/cnews/060206.html.

[7]

L. Lugmayr, “Philips Develops Plastic RFID Tag,” [Website], 2006 Feb 07, [cited 2008 Jan 23], Available HTTP: http://www.i4u.com/article5055.html

[8]

B. Bacheldor, “New System Reports Patient Falls,” RFID Journal, [Online Journal], 2007 May 15, [cited 2008 Jan 23], Available HTTP: http://www.rfidjournal.com/article/view/2462/1/1

Technical Review

[9]

Wasif M Khawaja – ECE 4884 Section L05/Dr Koblasz Group Name Care Takers

Phidget, “Phidget RFID,” [Online data sheet], 2007 Aug 8, [cited 2008 Jan 23], Available HTTP: http://phidgets.com/documentation/Phidgets/1023.pdf.