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Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
Technology fundamentals
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Technology fundamentals

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  1. CONTENTS 6 Building the body area network 17 Industry alliance tackles technical, policy challenges 29 22 European project helps manage broken hearts at home 27 Medical imaging makeover 24 29 Data acquisition systems allow stop-action cardiac imaging in one scan 33 Managing digital imaging’s mountains of data 27 38 Mixed-signal, embedded open doors for digital imaging 43 Automated blood test is a breeze “This digital edition was designed to play on most browsers using Adobe Flash 8.0 or 47 Camera in a pill surveys GI tract higher. Should you encounter any difficulties in viewing the edition, we suggest that you click on the logos below to install the most recent 52 Body fat meter is thinly priced versions of Adobe Flash and Shockwave players.” 60 Inside the art of pulse oximetry 2 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  2. Opinion Technology fundamental to reform By George Leopold or for blocking “fundamental reform” of a O nce the political posturing, demagoguery and horse trad- system that accounts from anywhere be- ing cease, it’s far from clear tween one-fifth to one-sixth of the U.S. whether Americans will actu- economy, depending on which Senate floor ally achieve health care re- speech you choose to believe. form. The guess here is that, in This is indeed a sad state of affairs, but time-honored Washington fashion, all sides not wholly unexpected, given the political in this noisy, high-stakes debate will claim and economic stakes for the health care political victory while condemning the other industrial complex. side either for effecting a “government Assuming Congress approves health takeover” of the U.S. health care system care legislation this year and President3 EE Times |The diagnosis for medical electronics | December 7, 2009
  3. Opinion Barack Obama signs it into law, a key question in implementing re- forms is what role tech- nology can play in reducing skyrocketing medical bills. Up to now, many diag- nostic technologies have greatly improved U.S. health care while saving countless lives. Those technologies re- main expensive, how- ever, making it awfully tempting for a medical specialist to order another high-ticket test—which may or may not be needed— Music: Cross Douglas Road by Patrick O’Rourke, www.patrickorourke.com4 EE Times |The diagnosis for medical electronics | December 7, 2009
  4. Opinion as a way to pay off the huge up- forms. One office worker left to take care system, but it is a critical tool front investment in the latest med- a job at Starbucks, where she could in the fight to put patients ahead of ical equipment. get the medical benefits the doctor profits and politics. p If we are to reduce medical costs, could not afford to provide. such practices must stop. It is physicians like this one who About the Author George Leopold is news director for Part of the problem with soaring desperately need technology’s help EE Times. health care costs is that medical to survive and, perhaps one day, email: gleopold@techinsights.com school graduates confront huge thrive. For technology companies that tuition bills that drive them into have created the senior position of lucrative specialty medicine and chief medical officer, a huge opportu- away from general practice. nity exists to customize existing tech- One of the best stories we’ve nologies to serve these medical seen during the health care debate professionals and not just the spe- focused on a general practitioner cialists whose offices are already who was struggling to meet the filled with the latest diagnostic tools. needs of her community and keep None of us is getting any younger, her practice afloat amid a ceaseless and some of us are facing life-and- tide of health insurance paperwork. death medical decisions about our The MD could barely afford to em- aging parents. Technology alone ploy file clerks to handle the flood of won’t heal what ails the U.S. health5 EE Times |The diagnosis for medical electronics | December 7, 2009
  5. Body area nets Building the body area network By Rick Merritt neering at the University of Washington, N etworked medical devices hold the promise of more-effective notes that much of that spending was for and lower-cost health care, as costly hospital care, often delivered long services traditionally delivered after the onset of chronic problems that in clinical settings become could have been better managed early on. accessible in the home. The rationale be- A critical component of the solution “is hind the shift is sound, but the business, in embedded or wearable devices linked to regulatory and technical hurdles are many. therapy,” said Joseph Smith, vice president The problem is clear: The United States of emerging technologies at Johnson & last year spent an estimated $2.5 trillion— Wearable devices and implants could 18 percent of its GDP—on health care. Yong-Min Kim, a professor of electrical engi- help cure what ails health care6 EE Times |The diagnosis for medical electronics | December 7, 2009
  6. Health care, American style High costs are due in part to late-stage treatments, administered with expensive equipment in hospital settings $2.5 trillion Johnson Services Inc. (New Amount spent domestically each year on health care Brunswick, N.J.), which oversees 18% dozens of medical businesses. Portion of U.S. GDP spent on health care “We don’t yet have the treatment 45% paradigms for continuous care for U.S. share of world health care spending in dollars chronic diseases, but I think we will 45-50 million get there,” Smith said in September Number of uninsured Americans at the IEEE Engineering in Medicine 66% and Biology Society’s annual confer- Percentage of Americans who are overweight ence (EMBC). 65 million “We all have a responsibility to Number of Americans with chronic heart problems be involved in health care reform,” 20 million: Rebecca Bergman, a vice president Number of Americans with diabetes of new therapies at Medtronic (Min- 100,000 neapolis), said at EMBC. “Tech is Number of people who die in the U.S. each year from preventable treatment errors not at the core of this issue, but we One hour should make tech part of the solu- Amount of time spent on paperwork for each hour of health care delivered in the U.S. tion and not part of the problem.” 50% A group from Australia reported Amount of U.S. health care dollars typically spent in the last six months of a patient’s life Sources: Yong-Min Kim, University of Washington; Joseph Smith, vice president of emerging technologies at at the conference on a program Johnson & Johnson Services Inc.; EE Times7 EE Times |The diagnosis for medical electronics | December 7, 2009
  7. Body area nets that remotely monitored former car- Mir Imran, who in the mid-1980s de- Business hurdles diac patients participating in an ex- veloped one of the first implantable It’s easy to think of ways to extend ercise program. The program, cardiac defibrillators. “I’m thinking today’s wealth of consumer and developed in conjunction with Nokia, about clinical problems and optimiz- computer technologies to medical helped reduce the number of pa- ing solutions for them, and leverag- applications. What’s harder is mak- tients readmitted to hospitals from ing electronics heavily—whether for ing such concepts reliable enough the typical 28 percent to 8 percent. drug delivery or new kinds of im- to earn the trust of the doctors who Such efforts are fueling interest in plants, or putting sensors where they would use them, the regulators who a rising tide of networked medical have never been, for example in a devices and services. “I’m in the hip or knee replacement.” thick of it,” said serial entrepreneur In one project, Imran is working with Texas Instruments to equip R R The body electric Julien Penders, a cardiac stents with an RFID tag, a microelectromechanical system (MEMS) flow sensor and a tiny radio to report on the flow of blood program manager for body area network through the passage. The goal is an technologies at IMEC (Leuven, Belgium), early warning system for the nearly offers a primer on 7 percent of stents that become BANs and wearable devices. blocked over time. Click image to launch video8 EE Times |The diagnosis for medical electronics | December 7, 2009
  8. Body area nets would approve them and the insurers geared for their special needs. But “if Analyst Stephan Ohr, who co- who would pay for them. a couple of [medical electronics] ven- authored a recent Gartner report on Jonathan Collins, principal analyst dors solidify around a particular wire- telemedicine, noted that “today, a at ABI Research, predicts the use of less spec, it won’t need to be a nurse comes to your home, takes wearable consumer fitness devices [standard on the scale of] Bluetooth,” your blood pressure and transmits will grow rapidly over the next few Collins noted. the reading to a remote doctor using years as the devices adopt standards EEG Body Area Network for health like Bluetooth. By contrast, devices & comfort monitoring Vision Hearing for professional clinical use in hospi- tals and homes will take longer to Positioning adopt proprietary technologies ECG Glucose Blood pressure R R POTS Heart and home Network DNA protein Philips describes how Cellular Toxins a variety of home sensors could work with cell phones and TVs to allow remote WLAN monitoring of patients’ cardiac conditions. Implants Source: IMEC Click image to launch video9 EE Times |The diagnosis for medical electronics | December 7,
  9. Body area nets an Internet connection, but more- care systems and services. By the ance providers. Despite the many automated patient monitoring using end of 2008, as many as 600,000 experiments, “the business models wireless is still 10 years out. The of the estimated 2.5 million im- in place today just do not get it biggest reason is that doctors don’t planted devices in use were linked to done,” LaLonde said. “I contend we trust [the new devices]—they really home systems that transmitted data are in a race to the bottom, in don’t know what to do with the automatically to clinics for remote which investment drives up expec- data—and insurance companies monitoring. But none of the compa- tations and more investment with- won’t pay for them.” nies providing those remote services out capturing value.” Indeed, the biggest challenge may is being adequately compensated be getting someone to pay for home for them, said John LaLonde, vice president of R&D for Boston Scien- R R Not just a Band-Aid Bandages one day could integrate tific’s pacemaker group, which has 150,000 implant users on its re- mote monitoring service. Some companies sell the remote active components services bundled into the cost of the that stimulate implants, LaLonde said; others the skin to speed healing, then lease the home devices and sell the let you know when services outright, and a few have se- they are ready to be Click image to launch video removed. cured reimbursement from insur-10 EE Times |The diagnosis for medical electronics | December 7, 2009
  10. Body area nets R R Dialysis untethered By 2014, startup Nanodialysis Global shipment forecasts for wireless body sensors: 2009 vs. 2014 Units (millions) Segment 2009 2014 CAGR (Eindhoven, (’09 –’14) Netherlands) hopes to field a wearable Sports and fitness 10.42 180.55 76.91% system for patients with kidney failure, In-home health eliminating regular trips to the hospital. management 0.35 59.41 179.31% Click image to launch video There are technical issues, too. For Hospital/clinic-based 0.88 180.48 189.95% monitors example, making sure that digital health records can be read by any Total 11.65 420.44 104.87% system in a way that’s both secure Source: ABI research and bandwidth-stingy is “a monumen- skin, but few users will fuss with the “That’s the big problem, and so far tal task involving many disciplines, gels. So researchers are working on researchers are just scratching the and it’s going to take 10 years to re- a class of dry sensors that could be surface of it,” said Lindsay Brown, a solve,” said entrepreneur Imran. worn in clothing, reliably detecting body area networking specialist at As for hardware, today’s monitor- microvolt-level biosignals while filter- IMEC (Leuven, Belgium). ing devices often require conductive ing out the noise that comes from Engineers at Analog Devices Inc. gels to make good contact with the brushing against skin and cloth. are combining capacitive converters11 EE Times |The diagnosis for medical electronics | December 7, 2009
  11. Body area nets R R Watch your step Sensors that clip on to shoes could A low-energy Bluetooth variant de- will be ratified in December. Compa- nies including CSR, Nordic Semi- ical Implant Communications Service signed to work on button-cell devices (MICS) band, a 402- to 405-MHz snip- pet of spectrum approved in the mid- 1990s for communications with monitor the gait of conductor and Texas Instruments external programmers and gateways. people who have difficulty walking, are testing chips for it. An IEEE The FCC approved 1-MHz sidebands helping to prevent 802.15.6 standard for BANs, mean- for MICS in March that developers debilitating falls. Click image to launch video while, is in an early stage of defini- such as Saurin Shah of Medtronic will tion. The FCC could rule before the support in next-generation chip sets and a ring of electrodes in a design end of the year on a request from GE for various uses, including one-way that could enable better sensors as Healthcare to allow a Wi-Fi variant for links between external devices. well as touch-sensitive surfaces. ADI BANs in the 2,360- to 2,400-MHz “The jury is still out on [which is also working on ways to inject a band. ZigBee is yet another player wireless approach will be] the win- signal into the body to measure im- with its own health care profile. ner,” said Karthik Vasanth, product pedance, for gauging fat content or The Continua Health Alliance, an line manager for the medical busi- even for modeling the dynamics of ad hoc industry group promoting ness unit at Texas Instruments. the skin, said Paul Errico, a strategic home care systems and services, Multiple wireless links will proba- marketing manager with ADI’s con- has blessed both Bluetooth and bly coexist in tomorrow’s BANs, sumer health segment. ZigBee to date. and all of them will likely have to be Another issue is which wireless Implants are already using the Med- tooled or retooled to meet medical technologies BANs should ride.12 EE Times |The diagnosis for medical electronics | December 7, 2009
  12. Body area nets R R Night patrol A wireless monitor Tapping into the brain Neural stimulators open new directions for implants beyond the heart worn at home can check for sleep apnea Now that implants are a well- this tipping point,” said company acquired in 2005 by with as much accuracy established therapy for a Christopher Chavez, who St. Jude Medical. That group as the more-complex handful of heart conditions, heads a neuromodulation will see its business in neural and more-expensive medical electronics compa- Click image to launch video systems now used only in clinics. applications’ unique requirements. At EMBC, a Shenzhen, China, re- nies are working on a host of new devices and uses for them. Many of the efforts are R Videos R search institute showed a modified focused on the brain. 802.15.4 media access controller A growing body of research using simplified protocols to en- suggests that well-targeted hance sensor node battery life. And electrical stimulation of Qualcomm showed a compressed nerves can generate positive Tim Denison, a senior engineering Mir Imran gives a tour of his design manager at Medtronic in Minneapolis, for the first implanted cardiac defibril- sensing algorithm that reduces the results across a broad range shows a prototype for an implant that lator, approved by the FDA in 1985 amount of data acquired and sent of conditions, from addiction listens to brain waves and stimulates and now used by thousands. Now a neurons to test for a variety of ailments. serial entrepreneur, Imran is helping on a BAN using any radio. Thus far, to epilepsy, Parkinson’s See the full story at: to establish a foundry for implants. the company has applied it to blood disease and depression. “I www.eetimes.com/showArticle.jhtml;? articleID=219500873" pressure and heart rate sensors. p think we are on the verge of13 EE Times |The diagnosis for medical electronics
  13. Body area nets implants rise from $24 mil- eight uses for neural stimula- declining number of smokers some kinds of pain and de- lion in 2000 to an estimated tors thus far. “We believe and rising use of stents to generative diseases,” said $320 million this year, each one is less than 10 per- lessen need for heart im- Richard Kuntz, chief science Chavez said. Industrywide, cent penetrated in its target plants. By contrast, more than officer at Medtronic. neural implants represent application, and 10 new uses a third of global health issues Earlier this year, Medtronic about a $2 billion business are still waiting to be ap- are neurological in nature, a said it had begun animal tri- today, growing at double-digit proved,” Chavez said. percentage that is expected to als of a closed-loop system rates to about $3.9 billion in The shift comes at a good expand as people live longer. to listen and respond to brain 2014, he estimated. time for implant makers, Pacemaker giant Medtronic waves automatically. The U.S. Food and Drug which are expecting the already has devices for ail- Neural stimulators have Administration has approved ments like Parkinson’s and been shown to be effective in Neural stimulators are “has a pipeline [of neural im- tests, though much of the un- plants in development for] derlying brain science remains effective in tests, but OCD [obsessive-compulsive a mystery. For example, de- much of the underlying disorder, depression, epilepsy, pressed patients who did not science is a mystery migraine, fecal incontinence, respond to shock therapy can14 EE Times |The diagnosis for medical electronics | December 7, 2009
  14. Body area nets be shown smiling in videos when with tissues taught to beat on their stimulated by a neural implant. own,” said Joseph Smith, vice pres- “It’s a little eerie,” said Kuntz. The future ident of emerging technologies at “We really don’t know how it works, belongs to Johnson & Johnson Services Inc. because we are talking about genetic (New Brunswick, N.J.). some of the most complicated But a more immediate task for therapies, physiology of the body.” companies such as Medtronic lies Jonathan Sackner-Bernstein, an some in shrinking the size of today’s associate center director at the researchers 10-cc cardiac implants, eliminating FDA, took a contrarian position in argue the electronic leads that are the one of several forums on deep cause of most failures. brain stimulation at an IEEE bio- “We believe it is possible to get engineering conference in Septem- tions in genetic therapies. this device down to 1 cc in size ber. “You still have to have brain Indeed, the long-term future be- without a lead, so the device itself surgery [to have an implant in- longs to biological treatments, is in the heart,” said Rebecca stalled], and I am not sure many many researchers believe. For ex- Bergman, a vice president of new people would want to have a scar ample, “we need to think different therapies at Medtronic. “We hope across their skull,” he said, calling and make a cell a genetically con- [to have such prototypes] in instead for more radical innova- trolled, programmable pacemaker, animals to define those issues15 EE Times |The diagnosis for medical electronics | December 7, 2009
  15. Body area nets in the near future.” designed by an expanding set of Others see further directions ‘The next sometimes small companies and for implants. revolution startups. Today most implants are “The next big revolution will be will be made by large, vertically integrated implantable, closed-loop drug companies, such as Medtronic and closed- delivery systems,” said Mir Imran, St. Jude Medical, that control most who developed one of the first loop aspects of the design. implantable cardiac defibrillators. drug “If you develop an implant today, “There are therapeutic proteins delivery you have to go to a dozen manufac- and peptides available, but they turers to put it all together,” Imran systems’ have to be delivered directly into said. “You end up spending three the brain because the stomach as an artificial pancreas for dia- times as long and 10 times as chews them up.” betes, Imran said. much money to get the result you Such devices will eliminate side Imran is working on as many as should.” — Rick Merritt effects when drugs are delivered to five different implant concepts the entire body. Closed-loop sys- today. He also acquired Modulus About the Author tems that can sense the need for a (San Jose), an implant maker, to Rick Merritt is editor at large of EE Times. drug and deliver a proper dosage bolster its role as a foundry for will be key to breakthroughs such devices that he believes will be email: rmerritt@techinsights.com16 EE Times |The diagnosis for medical electronics | December 7, 2009
  16. Telehealth Industry alliance tackles technical, policy challenges By Dylan McGrath to transmit their vital signs seam- I nformation technology is already used today to exchange health- lessly to the health care profes- related information, but proponents sionals monitoring their status. of the nascent telehealth concept Such technology, they argue, would see an opportunity to do far more. improve the quality of care while They envision a world in which elderly requiring fewer face-to-face doctor patients and others with chronic health visits, thereby increasing the effi- problems use connected medical devices ciency of health care delivery and17 EE Times |The diagnosis for medical electronics | December 7, 2009
  17. Telehealth containing its cost. a sea change in how they conduct adoption of telehealth solutions is Before that vision can be realized business. the lack of open, standards-based on a grand scale, however, there are According to Rick Cnossen, direc- architectures. technical, regulatory and cultural tor of personal health enabling for Cnossen, who is also president hurdles to clear, including getting Intel’s Digital Health Group, an and chairman of the Continua health care professionals to accept immediate obstacle to widespread Health Alliance, believes telehealth The making of an implant Although the market for internal medical devices is expanding rapidly, the process for making implants still relies heavily on painstaking manual labor Welcome to the foundry Small hybrids Ties that bond Mir Imran, developer of one of the first Imran describes the unique (hybrid, dense Wire bonding is one of the methods used to implantable defibrillators, opened the doors and flexible) printed-circuit boards used deliver dense boards for implants. of his Silicon Valley company Modulus to in implants. show how implants are made. Click images to launch video18 EE Times |The diagnosis for medical electronics | December 7, 2009
  18. Telehealth will not achieve its potential unless terfaces and revolutionized the way than 200 member companies, span- devices are based on nonproprietary computers communicate with pe- ning the gamut from tech heavy- protocols and are interoperable. ripheral devices. weights like IBM, Intel and Samsung “We’ve seen this [interoperability The Continua Health Alliance is Electronics to powerful health insur- scenario] play out time and time a nonprofit industry coalition dedi- ance firms such as Aetna Inc. and again,” said Cnossen. He pointed to cated to establishing a system of Kaiser Permanente Inc. the standardization effort around interoperable, connected personal Continua includes technical work- the Universal Serial Bus, which dis- health products. The organization, ing groups that evaluate existing placed a plethora of proprietary in- established in 2006, now has more Some assembly required In the can Technicians attach a battery and lead The pc board is then folded and inserted wires to each implant by hand. into a titanium container. Click images to launch video19 EE Times |The diagnosis for medical electronics | December 7, 2009
  19. Telehealth standards and work with standards have achieved certification. bodies such as the IEEE and ISO to Cnossen said he expects the bridge gaps on the road to interop- pace of certifications to pick up a erable telehealth solutions. Con- bit “now that we’ve got the ball tinua’s policy working groups lobby rolling.” The alliance is currently Laser welding governments with an eye toward working on version two of its influencing legislation. guidelines. In one of the few automated processes in the final assembly stage, a laser welder Taking a page from the playbook Continua’s initial thrust has heav- seals the titanium can. of the Wi-Fi Alliance, Continua has ily focused on the technical as- also established a rigorous test pects of creating interoperability and certification program to ensure between devices, Cnossen said, that products bearing the Continua but lately there has been a shift logo are fully interoperable. toward more focus on the organiza- In February, Continua announced tion’s policy activities. it had completed the first version In the United States, that effort A plastic hat of its design guidelines, developed consists primarily of pushing for A plastic header is fitted onto the can, forming a seal that also shields the lead for device manufacturers that in- more reimbursement for telehealth wires that attach to the body. tend to put their products through services from Medicare and Medic- the Continua certification process. aid. Similar lobbying efforts are Click images to launch video Since then, a total of eight products under way in other regions, notably20 EE Times |The diagnosis for medical electronics | December 7, 2009
  20. Telehealth Europe and Japan, Cnossen said. Another hurdle that telehealth technology, Cnossen said. “They Telehealth is taking off, Cnossen must clear, however, is getting doc- know this is happening. They want said, but it would grow more quickly tors to buy in. With demands on their to work with the industry.” p if government programs reimbursed time rising for training and other ac- providers for more services. “Gov- tivities, physicians are wary of how About the Author Dylan McGrath is West Coast online ernments can be a little slow to much effort might be required to editor at EE Times. change,” he said. “They like to see a accumulate and monitor the poten- email: dmcgrath@techinsights.com lot of data.” tially voluminous data generated by But with the debate currently connected healthcare devices. raging in Washington over U.S. Software that manages the flow of health care reform, and with a new information and provides high-level political party in power in Japan for analysis is therefore required, the first time in decades, this is a Cnossen said. time when Continua’s policy efforts Regulatory bodies that approve could have an impact, according medical equipment for disease to Cnossen. monitoring, such as the U.S. Food “In the U.S., we have a great op- and Drug Administration are also portunity over the next six months cautious, he said. that could be very positive for tele- Continua has had preliminary dis- health legislation,” he said. cussions with the FDA about the21 EE Times |The diagnosis for medical electronics | December 7, 2009
  21. HeartCycle European project helps manage broken hearts at home By Peter Clarke mix of hardware and software built A HeartCycle aims to create a closed-loop into everyday items such as cloth- feedback system to help cardiac patients ing and bedding could let cardiac monitor their conditions without numerous patients manage their health at visits to their physicians. The system home under the European Union’s would report automatically to clinicians so HeartCycle project. The four-year collabora- that if changes needed to be made in the tive research effort is part of a wider push treatment protocol or in the patient’s to find innovative ways to deliver health lifestyle, that information could be con- care more effectively—and at lower cost— veyed over a computer network. as Europe’s population grays. While face-to-face consultations are22 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  22. HeartCycle more personal, the monitoring en- Measurements, detection, prediction abled by systems such as Heart- Cycle could alert patients and clini- Important cians quickly to small changes in a decision point! patient’s condition that might not otherwise be spotted until they be- Telemedicine Analysis, decisions came serious problems. Such sys- tems would complement face- platform (e.g. MOTIVA) to-face visits, though ideally the lat- “At home”/Patient ter would be required less often— platform “At home” Medical and would less often take place Patient (e.g. MyHeart) healthcare professionals under dire circumstances. The HeartCycle project launched on March 1, 2008, and has a budget Value is created of 22 million euros (about $33 mil- by closing the loop! lion), with the EU providing about 14 million euros (about $21 million). The work is led by Philips Research (Aachen, Germany) and involves 17 other academic and industry groups, Therapy, feedback including Clothing Plus Oy (Kankaan- paa, Finland), Koninklijke Philips The HeartCycle closed-loop management approach comprises two loops. Electronics NV (Amsterdam, Nether- lands) and Medtronics Iberica SA23 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  23. HeartCycle (Madrid, Spain). Developing “the next generation of telemonitoring systems requires a multidisciplinary approach” that in- volves more than just bridging exist- ing islands of automation and networking, said HeartCycle project coordinator Harald Reiter, who is based at Philips Research. “Defi- nitely, the project is based on inno- vation,” Reiter said. “If you just try Bio-impedence monitor. to use the existing technology, it is not enough.” To that end, the project targets the “domestication” of a number of sen- Matsense sensor sor types and equipment. Some of the technology is in use now in hos- foil for the Smartbed pitals but is being customized for system. home use; other work involves novel sensors. One technology is a bio-impe- dence monitor (BIM), used to meas- ure the presence of fluid in the tissues. BIM systems can be used24 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  24. HeartCycle to predict decompensation, or the is the MatSense foil, a bed-sized inability of the heart to maintain ad- pressure sensor on which the pa- A vest with equate circulation. tient sleeps. Composed of an array Frequent home bio-impedence of capacitive sensors, it can provide textile measurement can open up the pre- both ballistocardiogram and move- electrodes diction window for decompensation ment signals. is one from only one or two days (via sim- Specific algorithms are being element of ple blood-pressure measurement) to developed to calculate heartbeat the in-home two weeks, according to Heartcycle intervals, respiration cycle and bio-impedance documentation. “This allows treating movement. The technology can be monitor. the patient at home, and the hospi- used to monitor sleep quality, tal is avoided,” said Reiter. as a change in sleep patterns could The challenge is to remake bulky hospital equipment so that patients The goal is a daily measurement procedure can manage the gear in a home set- ting. Toward that end, electronic tex- that takes only 15 minutes. Use of the vest tile developer Clothing Plus is ensures that electrodes are positioned the working on a measurement vest that same way on the body each time the test would let patients easily position is run. The measurement is started via an electrodes in the correct place for interfacing PDA and runs automatically. testing and might have to be worn for only 10 minutes a day. Another sensor within the program25 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  25. HeartCycle presage the need for an in-person Thus far, the EU project has under- The Clothing exam or a change in medication. taken extensive consultation to Plus-designed vest The flow of data and intelligence develop the usage cases and the should need to be across networks and around the requirements for equipment and worn for only a few system is a key aspect of the Heart- software. Preparatory work has also minutes a day. Cycle project. For example, auto- begun for a program of clinical trials. mated systems are needed to All of the equipment must be CE monitor the data, extract useful in- certified for medical device use, and formation and alert professionals at that requires planning. appropriate times. A longer-term goal is to include “There are not enough nurses to data from implanted devices such be looking at the data all the time,” as pacemakers, although that work said Reiter. “This is our main focus. is still in the conceptual stage, “While the networks for communi- Reiter said. cation will be ZigBee, Bluetooth, Clinical trials of HeartCycle tech- USB and so on, the algorithms to nology are due to start in March alert the nurses [must be devel- 2011 and could take six months to oped]; this is our major work.” one year to complete. Successful completion “would The Smartbed, based on the MatSense foil, About the Author mark the end of the project, but captures a person’s vital signs—including heart Peter Clarke is European news before that we will have pretrials to rate, breathing rate and sleep quality—during the director for EE Times. test and justify certain elements, night in an unobtrusive way, without the need to email: pclarke@techinsights.com including sensors and electronics,” glue electrodes to the skin. said Reiter. p26 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  26. Digital imagi ng Medical imaging makeover By Nicolas Mokhoff igital medical imaging is an en- D standards had to be established. The abler for the anticipated adop- Medical Imaging & Technology Alliance, tion of electronic medical a division of the National Electrical Manu- records by health care providers facturers Association, is the collective industrywide, replacing analog voice of medical imaging equipment devel- films—which must be carried by hand from opers and manufacturers. One of the one health care provider to the next—with group’s goals is expanded global accept- digital bits that are acquired, processed, ance of the Digital Imaging and Communi- seamlessly streamed to multiple locations cation in Medicine standard. DICOM allows via wired and wireless transmission, and digital imaging technologies to interact archived electronically for ready retrieval. Films carried by hand are giving way For it all to work as envisioned, to bits seamlessly streamed27 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  27. Digital imagi ng seamlessly, so imaging results can Analog Devices’ Scott Pavlik de- sheer volume. Samplify’s answer is a be shared among all the parties re- tails what he calls the most cutting- solution whose signal compression sponsible for a patient’s care, with edge technology for heart imaging in ratios provide reductions in data ac- an eye toward effecting the best the emergency room: CT scanners quisition rates from 2:1 up to 3:1. course of treatment. with data acquisition systems that Allowing the raw data to be readily Radiology began as a medical sub- can enable stop-action imaging of a repurposed avoids the need to repeat specialty in the first decade of the beating heart in one scan. The costly medical imaging procedures. 1900s, after the discovery of X-rays. equipment produces a complete Texas Instruments’ Suribhotla For the first 50 years of radiology, image in just one rotation around (Raja) Rajasekhar addresses the the primary examination involved the body, completing the scan so trends and challenges affecting the creating an image by focusing X-rays quickly that the heart does not move electronics for various imaging through the body part of interest appreciably during the procedure. In modalities, including digital X-ray, and directly onto a single piece this way, the scan does not need to ultrasound, CT scan and MRI. Digital of film inside a special cassette. be synchronized with the period be- imaging in the 21st century, Ra- Digital imaging techniques emerged tween heartbeats. jasekhar notes, promises superior in the 1970s with the first clinical Samplify’s Allan Evans and Al diagnostic capability, image archiv- use and acceptance of the com- Wegener observe that the sharing of ing and on-demand image retrieval puted tomography (CT) scanner. medical imaging data among health anytime, anywhere. p In the three contributed articles care providers requires portability that follow, authors from Analog De- not only of the reconstructed images About the Author vices, Samplify and Texas Instru- but also of the raw data used to re- Nicolas Mokhoff is research editor of EE Times. ments touch upon the main issues construct the images. The challenge that make digital medical images in archiving such data in the context email: nmokhoff@techinsights.com such powerful diagnostic tools. of electronic medical records is its28 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  28. Signal acqui s i t i on Data acquisition systems allow stop-action cardiac imaging in one scan By Scott Pavlik he most cutting-edge technology T during the procedure; therefore, the proce- for heart imaging in the emer- dure does not need to be synchronized gency room is a computed to- with the period between heartbeats. mography (CT) scanner that can If this can be achieved, the patient does provide a high-quality image of a not need to go through the extensive prep patient’s heart with one scan and very little of having an ECG (electrocardiogram) at- prep time. Two factors are key to achieving tached and monitored to pinpoint the exact this: The CT scanner can do the entire time between beats when the heart is still. image in one rotational scan around the The resultant time savings enables a quick body, and the scanner is fast enough so diagnosis and saves costs. that the heart does not move appreciably To get a complete, accurate image in one29 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  29. Signal acqui s i t i on revolution, a 256-slice scan must be Those specs lead to a system that diode. The photodiode current (I) is done, for a sufficient horizontal reso- needs 256,000 channels of fast, converted to voltage (V) through a lution of about 0.5 mm. To achieve accurate data acquisition. Each low noise I-V amplifier/integrator. sufficient radial resolution, about channel includes a crystal scintilla- The I-V channels are then multiplexed 1,000 scanning channels are used. tor that converts X-ray energy into through a 24-bit, 128-channel A/D light, which is detected by a photo- converter, and the digital outputs are fed to the signal processor to pro- Single slice vs. Multi slice vide the decoded CT image. Analog Devices Inc.’s ADAS1128 24-bit, 128-channel A/D converter packs this capability into a 10 x Detector array CrystalScintillators convert X-rays to light, followed by photo diodes that generate current proportional to light and Linear pixel vs. Grid area pixel X-ray intensity, which is detector array detector array measured by Current-to-digital (1 pixel by Y pixels) (X pixel by Y pixels) converters Data Acquisition Systems (ADCs) 1,000 AFE signal chains per slice30 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  30. Signal acqui s i t i on 10-mm mini-BGA using 4.5 Ultrasonic the moving particles can be used Frequency and/or mW/channel. The total power Transducer phase of reflected to calculate the particle, or flow, sound changes with for the data acquisition section velocity. With a finely focused ul- speed/direction is then just over 1 kW for a of blood flow trasound beam, the velocity can 256-slice system, enabling a be plotted across the width of better than 50 percent power the blood vessel to determine reduction over typical equip- uniformity of blood flow. If the ve- ment of comparable complexity. locity plot is the classic parabola, Overall power is further re- then there is smooth, laminar duced by the improved speed. flow; a distorted pattern would Applications include dynamic reveal obstructions or structural imaging, to observe the heart problems in the vessel. or other organs in motion. The use of a pulse ultrasound waveform provides additional in- Finding blood flow anomalies formation by measuring transit The blood delivery system has A CW signal or pulse is sent into the blood time to provide a map of a given two major components: the stream and reflected back from the cells. vessel. While the technique can heart and the vascular system be valuable for diagnosing and of arteries, veins and capillaries. uous wave (CW) signal, usually a locating vascular disease, it will also Doppler ultrasound imaging systems sine wave, or pulse into the blood become increasingly useful for diag- can be used to determine blood flow stream which is reflected back from nosing traumatic injury and stroke. rates as well as identify blockages, the blood cells. As in all Doppler sys- The pulse ultrasound image can be restrictions or leaks. tems, the change in frequency result- used to find stoppage or leakage in Doppler ultrasound sends a contin- ing from the wave’s interaction with the flow pattern.31 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  31. Signal acqui s i t i on Ultrasound signal acquisition is at- Doppler ultrasound enables fast point-of-care diagnosis tenuated by the square-of-the-dis- of vascular anomalies that can lead to disease tance law, both in transmission and in reflection, leading to the need to Stroke •Progressive blockage of brain arteries (ischemic) handle a dynamic signal range ap- •Rupture or aneurysm (hemorrhagic) proaching 160 dB. One development Carotid artery blockage •Progressive blockage of arteries to brain that provided ultrasound systems •Most common cause of paralyzing strokes with the accuracy and discrimination Heart disease •No. 1 cause of death in the U.S. needed to provide clear images was a combined low-noise amplifier and Abdominal aortic aneurysm (AAA) •Tenth leading cause of death in men 50+ I&Q demodulator or phase shifter •700,000 undiagnosed in U.S. developed by Analog Devices. The concepts have been expanded to yield the AD9276/77. Ultrasound designers can now de- velop smaller systems for use in point-of-care applications. p Peripheral artery disease •Poor circulation in the legs About the Author •Can cause serious disability •Can lead to amputation Scott Pavlik is worldwide strategic •20% of people 70+ have PAD marketing manager for Analog Devices’ Healthcare Group. He holds a BSEE from Clarkson University. email: scott.pavlik@analog.com32 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  32. Data Compres s i on Managing digital imaging’s mountains of data By Allan Evans and Al Wegener t no time has digital imaging been A only for archiving of final images created more important to medical imag- by medical imaging technologies, but also ing applications than in today’s cli- for storage of the raw data from which mate of health care reform. those images are formed. In an environ- Indeed, the current U.S. economic ment where medical records are trans- stimulus program calls for $19 billion in ferrable from one health care provider funding to facilitate health care providers’ to another, portability of the raw data en- adoption of electronic medical records. ables that data to be repurposed for dif- Such a move will drive up demand not ferent end uses and thereby avoids the33 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  33. Data Compres s i on need to repeat costly medical imag- data from a single CT scan can be Among the imaging modalities, ing procedures. reused to form volumetric images CT scans could benefit the most Among the imaging modalities, that can support multiple end uses. from raw-data portability computed tomography may stand to For example, when the X-ray data benefit the most from raw-data from the scan is first captured, gen- portability to support multiple end erally an image is reconstructed to ogist may retrospectively recon- uses. First, CT scans are expensive, support an initial diagnosis by the struct new volumetric images using running in excess of $1,000 per attending radiologist. If a second different back-projection algorithms scan, second only to MRI. Second, opinion is required, a second radiol- to highlight certain anatomical Click either image for correct answer34 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  34. Data Compres s i on Click either image for correct answer features. If the diagnosis requires CT image data captured in digital CT image data captured in surgical intervention, the surgeon form becomes portable across digital form becomes portable may utilize the CT data to plan a health care providers, enabling the across health care providers laparoscopic or endoscopic proce- patient to seek the provider who can dure. Finally, the CT data might be provide the greatest probability of a used a fourth time, as registration successful outcome, without having bility of medical imaging data among of the anatomical features to to pay each provider to repeat the health care providers requires not guide the surgeon during the surgi- costly scans. just portability of the reconstructed cal procedure. As we have just illustrated, porta- images, but also portability of the35 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  35. Data Compres s i on X-ray or sonogram data used to re- Signal compression holds the authors challenge the readers to construct the images. The challenge promise for enabling portability pick which image was formed from for archiving this data in the context raw data and which one from com- of medical imaging data of electronic medical records is its pressed data. sheer volume. Samplify has performed similar A modern CT machine captures greatly exceeds the time to repeat studies with ultrasound OEMs, using X-ray data at a rate of 1 Gbyte/ the scan. images formed from pre- and post- second, resulting in 30 Gbytes for a Signal compression represents a beamformed data at compression 30-second scan. Ultrasound can promising solution to the problem of ratios of up to 3:1. Another image generate similar volumes of data, portability of medical imaging data. with each frame composed of hun- In a paper presented at the SPIE dreds of scan lines that themselves Medical Imaging Conference in Feb- are composed of thousands of sam- ruary, Samplify Systems, GE Health- ples. At 30 frames per second, ultra- care and Stanford University sound data acquisition can exceed demonstrated the efficacy of signal 20 Mbytes/s and result in data sets compression, in both lossless and on the order of 10 Gbytes for scans near-lossless modes, to achieve lasting a few minutes. compression ratios that provide The size of these data sets can be compelling reductions in data acqui- a limitation to their portability if they sition rates, from 2:1 up to 3:11. A cannot be easily provided on a stor- set of images accompanying this ar- age medium to the patient, or if the ticle (page 34) presents one of the time to transmit them from one image pairs used in the survey that health care provider to another was highlighted in the SPIE paper;36 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  36. Data Compres s i on set accompanying this article (page promise of reducing health care bedded in the data acquisition 35) repeats the image comparison, costs by increasing the portability silicon without added cost relative to but with ultrasound images. Again, of medical imaging data and there- that of existing A/D converters built the authors challenge the readers by reducing the need for duplicate on legacy processes. p to find any differences—and this scans. References time we have even made it easier Moreover, signal compression can 1Wegener A., Chandra N., Ling Y., Senzig R., Herfkens R. 2009. Real-time compression of raw by showing wire phantoms. provide this benefit while actually computed tomography data: Technology, architec- By providing a 75 percent reduc- decreasing the cost of medical ture and benefits. Proceedings of the SPIE Medical Imaging Conference, Vol. 7258 (March). tion in the storage or transmission imaging equipment, by reducing data http://tiny.cc/6Nemt requirements for medical imaging acquisition times. data, signal compression makes the In CT machines, faster data ac- data portable by enabling the data quisition rates result in lower costs sets to be provided to the patient on for mechanical rotary joints or slip low-cost dual-layer DVDs or by reduc- rings as well as for the RAID drives ing the transmission time for send- used to buffer the data prior to ing the data sets from one provider image reconstruction. to another. Similarly, signal compression in Signal compression provides the ultrasound machines reduces I/O bottlenecks between the analog About the Authors front end and the digital signal Allan Evans is vice president of marketing processing elements. at Samplify Systems Inc. Signal compression can be em- Al Wegener is Samplify founder and CTO. email: AEvans@samplify.com; AWegener@samplify.com37 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  37. M ixed-signa l apps Mixed-signal, embedded open doors for digital imaging By Suribhotla (Raja) Rajasekhar igital imaging in the 21st cen- D ties in imaging systems, leading to tremen- tury comes with the promise of dous advancements in medical imaging. At superior diagnostic capability, the same time, embedded processors image archiving and on-demand have dramatically increased the capabili- retrieval anytime, anywhere. ties for medical image processing and real- Since the advent of digital techniques for time image display for faster and more medical imaging in the early 1970s, digital accurate diagnosis. imaging has grown significantly in impor- The convergence of these technolo- tance. Recent advances in design capabili- gies, coupled with emerging standards for ties for mixed-signal semiconductors offer electronic health records, is providing the unprecedented electronics packing densi- impetus for better patient care.38 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  38. M ixed-signa l apps Digital X-ray systems Conventional X-ray sys- tems use a film/screen setup to detect the X- rays transmitted through the body. By contrast, the digital X-ray’s signal chain in the detector system comprises a photode- tector array that con- verts radiation to an electric charge. Charge integrator circuits and analog-to-digital con- verter circuits then digi- tize the inputs. A block diagram of a typical digital X-ray system is shown at left. Digital X-ray system X-ray: Medical/Dental solution performance is closely Source: Texas Instruments related to the noise performance of the39 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  39. M ixed-signa l apps integrator and ADC blocks. The level of Bringing ultrasound electronic integration required to support to the patient: Victims a large number of signal channels in a of war (l.) and natural system for higher image quality at low power consumption sets the bar for inno- disaster (below) can vation. The high-performance analog com- be quickly assessed ponents that make up the detector on site. system, as well as the embedded proces- Photos courtesy of SonoSite sors that perform advanced image pro- cessing, offer advantages over conventional X-ray systems, supporting a wide dynamic range that potentially re- sults in better image contrast and lower levels of X-ray exposure, while generating digital images for electronic storage and transmission. low-pass filter and high-speed, high-res- olution ADC. These elements are fol- Ultrasound systems lowed by digital beamforming, image The receive channel signal chain of an ul- and Doppler processing, and additional trasound system includes a low-noise am- signal processing software. plifier (LNA), variable-gain amplifier, The noise and bandwidth characteris-40 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  40. M ixed-signa l apps tics of the signal chain components define the system’s overall perform- ance ceiling. There is a thrust to inte- grate more high-performance channels in smaller areas, while dis- sipating lower system power. Typical handheld ultrasound systems would have about 16 to 32 channels, whereas high-end systems might have well over 128 channels for en- hanced image quality. To reduce the printed-circuit board footprint for the full array of these channels, the focus is to integrate as many channels as possible in the analog front-end IC. Power consump- tion in the overall system is another important performance metric for handheld systems. Another area of innovation is to in- tegrate the receive-side electronics This child’s grainy “first . . . This toddler’s in utero directly into the probe. This could baby photo” was closeup was captured just help reduce the distance from the recorded in 2003 . . . three years later. low-voltage analog signal sources in41 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  41. M ixed-signa l apps the probe to the LNAs and, hence, bits minimum) and how to realize packaging and compliance with more could reduce signal losses. Integra- very high total dynamic range (of stringent power dissipation and area tion could further increase the num- about 150 dB/Hz minimum) for the constraints may be required. A suc- ber of probe elements, thereby overall system. Achieving high SNR cessful implementation could pro- enhancing 3-D imaging. demands a high-performance pre- vide advantages such as reducing Apart from the analog signal chain amp with an ultralow noise figure. input signal attenuation to provide considerations, the high-performance The high-dynamic range requirement higher-quality medical images. and low-power embedded processors is realized via such schemes as dy- Digital imaging is one of the most can perform beamforming and image namic gain adjustment or analog active areas of technological devel- processing faster and more efficiently input compression. opment in medicine, driven by ad- than was previously attainable in a In general, the number of coils em- vancements in analog/mixed-signal portable-form-factor device. ployed in an MRI system is expected capabilities and embedded process- to increase, yielding better image ing. The available technologies MRI coverage and faster image scans. boost the performance of imaging A full-body MRI system could have a That increase may require further op- systems and ultimately enhance the coil matrix with as many as 76 ele- timization in the signal communica- quality of medical care. p ments or channels. Additionally, the tions between the coils and low-voltage analog inputs travel preamps, and with the main system About the Author down long coax cables from the ex- when using high-speed digital or opti- Suribhotla (Raja) Rajasekhar is a design engineer at Texas Instruments. He holds tremity coil to the analog signal cal links. Additionally, high levels of an MS from Johns Hopkins University, chain preamp. Two key challenges integration could lead to changes in a BTech from the Indian Institute of Technology in Chennai and an MBA from stand out for the MRI receive signal system partitioning, perhaps by mov- the University of Texas at Austin. chain: how to achieve high signal-to- ing the electronics closer to the email: ti_raja@list.ti.com noise-ratio (of about 84 dB or 14 coils. As a result, nonmagnetic IC42 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  42. Automated blood test is a Breeze By David Carey ersonal blood glucose monitors Built-in code for sample analysis P have evolved to become afford- able and highly portable electronic devices. The BGMs in use today are little electrochemistry labs. The Ascensia Breeze, made by Bayer AG, is one of several major brands of BGMs. All rely on the same basic techniques for takes some of the sting out of a still-invasive process Ascensia brings a level of convenience to monitoring by use of a disk containing the chemistry needed for measurements. The individual test strips of many other meters measurement: A small sample of blood are replaced in the Breeze by an inserted from a skin prick is collected and supplied cartridge disk system that holds 10 sam- into a chemical reaction by way of a test ple strips. strip or sample collector, which interfaces Whereas traditional meters require the to system electronics for electrochemical user to manually enter the coding data analysis. stamped on the sample strip box to adjust43 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  43. Glucose met er Catalyst Semi #CAT25C32V1 Serial E2PROM memory—4 kbytes Custom ASIC #36000025H Analog ASIC/Coulometer NEC #uPD78F0338GC 8-bit microcontroller with memory and peripherals for variable reactivity, with the As- error-free calibration data is auto- a 10-test disk and cycles the pull censia Breeze the coding informa- matically known. As with consumer bar at the Breeze’s lower end to ex- tion is built in. By eliminating the electronics of all stripes, ease of pose a test strip. Once a blood sam- human dimension of data entry cod- use applies: To perform a test, the ple is applied, a reading is ready to ing, the smart disk ensures that user simply opens the meter, inserts be taken.44 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  44. Glucose met er I didn’t buy a disk, so I can’t fingers. Signals are then routed to Starting with the business end of speak to the particulars inside that the door hinge, where a zebra strip the design, a custom ASIC consumable element of the design. connector routes the connections to (3600025H) is responsible for the But the presence of a polymer-thick- the circuit board assembly in the en- electronics side of the electrochem- film flex circuit in the Breeze sug- closure portion of the Breeze’s istry used in the glucose monitor. gests an electrical readout of clamshell design. (Back to that point Given the proprietary nature of the calibration information from the in a moment.) chip, details are sketchy; but to a disk, perhaps stored in a small, in- A fairly complex mechanical appa- first order, the part must be support- expensive serial memory chip or ratus in the main clamshell housing ing the coulometry used as the even through something as simple contains the indexing apparatus as a laser-trimmed resistor. The con- both to present a test strip from the necting flex circuit—located on the disk and to index to new test strip flip door used to house the disk— sites when the test is complete. A makes contact by spring-loaded pin rotating ratchet mechanism spins the disk a notch after The presence of a every use by translating polymer-thick-film the reciprocating motion used to expose the strip flex circuit suggests into a rotary motion electrical readout of simultaneously. calibration data The Breeze’s single rigid circuit board is home to three chips, all of which are powered by a single lithium coin cell battery.45 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  45. Glucose met er basic glucose measurement tech- electrochemical test measurement host PC. To hold reading data for re- nique. Constant current (ampero- and is calibrated for coded reactive view or download, the unit employs static) or constant voltage (potentio- variations, the output is sent to an 4-kbyte E2PROM from Catalyst. static) coulometry essentially counts NEC µPD78F0338GC microcon- Consumables are about $6 to $9 the number of electrons needed to troller. No A/D converter from the per disk. The Breeze meter likely complete the reaction of the test ASIC is obvious at the die level, so it has manufacturing costs in the $10 strip chemistry and the blood sam- seems plausible that signal conver- to $15 range-—a fraction of its $70 ple. Glucose levels are presumed to sion takes place in the NEC part’s to $80 price. correspond to differing coulometric internal A/D, where it can be manip- Noninvasive BGM solutions are on readings acquired in the mostly ana- ulated to a displayed glucose level the drawing board, but none has log ASIC, and the disk’s calibration on the Breeze’s segment LCD. reached commercial consumer cost data is also connected to the chip The LCD is driven directly by the targets with the accuracy of direct by way of the previously mentioned microcontroller, which also handles measurement. flex circuit connector. the button input. Similarly, the NEC Until that is achieved, the coulom- Once the ASIC has completed its device is used to interface to the etry and supporting electronics of product’s headphone-style connec- the invasive BGM have been en- The meter likely costs between tor, which implements a data port to hanced with automated sample pro- $10 and $15 to manufacture— allow the unit’s 100-reading memory cessing to take some of the sting a fraction of its $70 to $80 price to be downloaded for analysis on a out of a tough task. p46 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  46. Camera in a pill surveys GI tract By David Carey t’s not quite at the level of Harry The body’s motility provides the I Kleiner’s 1966 movie classic “Fantas- tic Voyage,” but Given Imaging Ltd.’s PillCam is an intriguing step forward. Able to provide physicians with an in- ternal view of a patient’s digestive path, the PillCam is an ingestible diagnostic tool that provides images of the small intestine PillCam locomotion; advanced electronics make the rest possible packaging to devise an endoscopy ap- proach that goes down a little easier: The patient swallows the camera pill, the capsule progresses via natural processes without invasive surgery or probes. through the digestive tract, and image data The traditional endoscopic process relies is relayed to an external receiver belt for on a tethered apparatus. Given Imaging eventual download and diagnostic review (Yoqneam, Israel) used ultra-efficient by a doctor. CMOS design (to keep power consumption The PillCam is about the size of a to a minimum) and dense optoelectronic megavitamin, at 26.4 mm (almost exactly47 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  47. C amera in a p i l l Transmitter layer Side 2 Coil antenna Lens/Illumination layer Imager layer Switch layer Transmitter layer Side 1 TEW GIT (foundry unknown) 27-MHz crystal Plastic lens #20481 (custom) Transmitter/controller Photobit (Now Micron) Reed switch (2) Eveready White LED #GILO_P (custom) #399 256 x 256-pixel color CMOS 1.55-V/55-mA-hr silver image sensor oxide watch battery 1 inch) long and 11.3 mm (0.45 transmission and control circuits to the lower shell to provide a view- inch) wide—not teeny, but ingestible within a two-piece biocompatible through window for the camera lens by most patients. It weighs a mere plastic capsule. An opaque lower located inside. 4 grams and contains all image- shell surrounds most of the elec- The clear dome also allows a capture, illumination, activation, tronics, while a clear dome is fused set of six miniature white LEDs48 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  48. C amera in a p i l l surrounding the lens to illuminate current-limit resistors. 165 mW-hr of total available energy. the gastrointestinal (GI) tract as the Below the lens level is the imager Since the device runs for up to pill moves through it. layer, home to a 256 x 256-pixel eight hours, a time-averaged power CMOS color image sensor. Markings draw of approximately 20 mW is Playing doctor on the chip indicate it is a custom Now it’s our turn to have a look in- device from Photobit, a company ac- The camera offers a 140° side the pill. quired by Micron Technology in 2001 viewing angle and 0.1-mm After an incision at the seam of and spun out as Aptina in 2008. feature resolution the two case halves (I’m already Combined with the plastic feeling a little medical here), the lens, the camera offers a capsule can be popped open and claimed 140° viewing angle the stack of electronic components and 0.1-mm feature resolu- removed. Five distinct strata form tion within the GI tract being the capsule internals, with various imaged. forms of interconnect between the layers of circuits. Power management Starting at the top level-—that is, Behind the imager layer is a the level closest to the transparent pair of Eveready No. 399 sil- portion of the capsule-—we find the ver oxide watch batteries, lens/illumination layer. An annular wired in series to create the printed-circuit board surrounds the sole 3-volt supply for the Pill- single plastic molded lens, support- Cam. The two button cells ing the LEDs and their associated provide 3 V at 55 mA-hr, or49 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  49. C amera in a p i l l implied. lowing, the reed switch closes, and RF emission guidelines The switch layer located behind power to the PillCam begins to flow. Per FCC filings, the transmitter oper- the batteries provides the means The final strata of the PillCam— ates at either 432.13 or 433.94 to preserve precious battery energy the transmitter layer—is home to MHz, with minimum-shift-keying mod- before the PillCam is ingested by the only other integrated circuit in ulation. MSK has the general bene- the patient. A reed switch mounted the unit: a custom ASIC developed fits of providing constant-envelope on the switch layer circuit board is by Given Imaging and of unmarked modulation, transmitter simplicity held open by a magnet in the Pill- foundry origin. The chip must pro- and good spectral efficiency. A sim- Cam’s shipping holster, interrupting vide system control along with radio ple air coil is the radiating antenna the battery connection. When the transmission. A 27-MHz crystal lo- package is opened and the capsule cated on the reverse side of the is removed from its holster for swal- transmitter layer is consistent with both functions. The 3.2 x 3.5-mm flip-chip appli- cation-specific IC contains a small block of logic, a very small memory array and a variety of mixed-signal circuits. Since the output from the image sensor is presumed to be preconverted to digital form, the radio and LED drive circuits are the The PillCam measures about likely functions included in the ana- an inch long—not teeny, but log portion of the ASIC. ingestible by most patients50 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  50. C amera in a p i l l element, tucked into the rounded the batteries, and a pair of gold- capsule end opposite the camera. plated coil springs distributes power Transmit power is held low to man- from the imager layer to the lens/il- age power consumption, as the re- lumination layer through holes in the ceiver antennas are in proximity to lens barrel. the waist-worn monitor. The eight-hour PillCam lifetime Nevertheless, FCC filings indicate provides up to 57,000 images at a the PillCam stays within emitted RF rate of two frames per second, with guidelines only when the pill is in- the LEDs flashing only during image side the body. The minute or so that capture. Given the limited available it takes the pill to go from acti- energy, the combination of low- vated/depackaged form to ingestion power CMOS imagers, spartan is apparently given a waiver as part logic, efficient radio design and of the PillCam’s regulatory approval. pulsed white LEDs for illumination is critical. Single board Bringing all these pieces together The image capture, switch and to create an ingestible camera-bot is transmitter layers are all fabricated an amazing benchmark in technical on a single rigid-flex printed-circuit progress. The body’s motility pro- board. Delayering the board among vides the PillCam locomotion, but the three islands of functionality advanced electronics make the rest creates flex circuits to interconnect possible. those regions. It certainly brings new meaning to The assembly is folded up around the phrase “internal medicine.” p51 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  51. Body fat meter is thinly priced By David Carey here always seems to be some T The HBF-306 resembles a handheld medical widget at my local Wal- game controller, with two handles gripped green’s that gets the wheels of cu- by the subject during the measurement riosity turning. This time it was process and a center “pod” containing Omron’s $50 (or less) HBF-306 per- measurement electronics. The handles sonal body fat meter. It’s not ordinarily the contain two electrodes each, formed by pre- kind of device people pick up for fun; but sprung metal encircling the plastic enclo- along with my technical curiosity about how sures. Test subjects wrap their hands it worked, I thought it might help me check around the grips, making contact with the my progress in keeping off the pounds. As electrodes. AAA batteries power the device, it turns out, the device functions on a sur- prisingly simple premise with correspond- The HBF-306 functions on a simple ingly spartan—and mostly analog— premise, with spartan electronics electronics used for implementation. that go heavy on the analog52 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  52. Body fat me t e r further evidence of the elegantly bines the results with user input and age. From what I could determine, simple electronics within. correlated lab-gathered data to esti- Omron accumulated a database of With a retail price as low as $30, mate body fat percentages. fat percentages with a large and pre- there’s little budget for fancy med- The human body’s conduction has sumably varied group of test sub- ical-grade monitoring. Traditionally, both a resistive and reactive compo- jects using the traditionally accurate accurate body composition measure- nent, with the resistance being means mentioned previously. By ment relies on dual X-ray absorp- driven by water-bearing tissue and knowing lab-grade numbers for each tiometry or hydrostatic weighing, the capacitive reactance stemming person and measuring the imped- which records the apparent weight from the insulating membranes ance corresponding to each case, of a subject underwater with the around each cell. Lean tissues are Omron developers created the data- lungs emptied of air. Measurements characterized by a relatively low re- base. The assumption is that any of body folds and other physical sistance, with fat and bone being given result with the HBF-306 can be characteristics are also common. poor conductors, given their low re- assigned a percentage of body fat The Omron unit clearly lacks X-rays, tention of fluids and electrolytes. corresponding to more rigorously ac- a test pool or a set of calipers, so Determining a precise RC model to quired lab data (once corrected ac- something else is going on. mimic the human body has been a cording to the user-specific inputs). With a bit of poking around on subject of debate, but to a first The method isn’t perfect and is Omron’s Web site and through the order, the impedance can seemingly subject to other variables. The hand patent literature, it becomes clear be modeled as a parallel RC circuit. contact during measurement must that the HBF-306 relies on bioelec- Measurements begin by having the be steady, and Omron’s patents indi- trical impedance analysis. BIA meas- subject enter sex, height, weight and cate a narrow range of time-lapsed ures the subject’s body impedance, age. The device adjusts for variables readings within which impedance recorded under carefully controlled that affect impedance and its ulti- must be seen, or the test will abort. measurement conditions, and com- mate correlation to body fat percent- The instructions also indicate that53 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  53. Body fat me t e r the user must have both arms ex- cause electrical shunts, which might circumstances under which reliable tended to 90° angles in a standing poison the measurement and corre- readings may be achieved. Adjust- position and with feet spread lation. Finally, because the body’s ments for musculature and nominal slightly apart. These requirements impedance varies over the course of subject conditioning (“athlete all speak to the need for a pre- the day with fluid intake and activity, mode”) are also possible. dictable body geometry that doesn’t Omron outlines specific times and The Omron device essentially Texas Instruments Renesas #SN74LV4066A Texas Instruments #M38223M4H Quad bidirectional #SN74LV4052A 8-bit microcomputer with analog switch Dual four-channel analog 2-kbyte mask ROM multiplexer/demultiplexer ST #TS924 Quad op amp Seiko Instruments #S-93C46 Serial E2PROM memory—128 bytes54 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  54. Body fat me t e r comprises a simple impedance mux/demux chips and a single TI lation data or measurement results. meter and a little database. Be- SN74LV4066 quad bidirectional ana- A CEM circuit board provides a cause complex impedance is to be log switch create what might be an low-cost substrate on which to measured, an ac signal must be analog signal fabric, suggestive of a mount the ICs and 80-odd discrete used; here, Omron implements a reversing circuit to make measure- and passive components. The board constant-current 500-µA, 50-kHz sig- ments in two directions. That bit is a uses cost-saving, silver-paste-filled nal applied across two of the four little unclear. via holes with a sealing overprint. electrodes—one for the left hand, The biggest IC is a Renesas All told, a few bucks for chips and the other for the right. The two re- M38223M4H 8-bit microcontroller support components and less than maining electrodes serve as the with 16-kbyte ROM and 512-byte $10 for display and casing add up to pickups to sense the impedance by RAM-—nothing new, given a die-level a roughly $15 parts cost that, com- measurement of the voltage rise 1986 copyright date. The microcon- bined with clever software, offers an and phase shift caused by the equiv- troller has A/D circuit peripherals for inexpensive way for folks to estimate alent RC circuit of the body. digitizing demodulator and amplifier their body composition. (I did OK on Electronics for the analog-meter outputs, along with the digital smarts my own test, but I didn’t knock it out front end are limited to an STMicro- to do measurement lookup and cor- of the park. See you at the gym.) p electronics TS924 quad op amp, relation of body fat percentage. likely used partly for the oscillator, The user interface of front-panel About the Author partly for the detected voltage ampli- switches and the direct-drive mono- David Carey is president of Portelli- fier to determine resistive values chrome LCD are also in the line of gent (Austin, Texas), which produces teardown reports and related industry and partly for implementation of a duty for the Renesas part. A 1-kbit research on wireless, mobile and per- demodulator, which serves for phase Seiko Instruments serial E2PROM sonal electronics. detection. Two Texas Instruments supplements the controller’s on-chip email: dcarey@portintelligent.com SN74LV4052 four-channel analog memory, perhaps storing code, corre-55 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  55. Track your blood pressure for $60 By David Carey ortable instruments have assumed P likely the top maker of blood pressure a high-profile role in personal monitors for personal use, and the group’s health monitoring. Here we exam- focus is firmly rooted in health-monitoring ine the Omron Intelli-Sense HEM- products for both consumers and medical 711AC blood pressure monitor, professionals. which accomplishes some sophisticated The HEM-711AC comes with the familiar metrology for a surprisingly low price, in a arm cuff and a base unit roughly the size package that’s usable at home or on the of a small paperback. While not tiny go. With a retail price of around $60, the enough to fit in a pocket, the device is cer- product clearly relies on low-cost design, tainly portable, and a push of a button is but the need for accuracy also required some clever engineering. With clever engineering, Omron’s Omron Healthcare Inc., a division of the portable monitor turns capacitance diversified Kyoto, Japan-based Omron, is changes into useful data on the cheap56 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  56. Blood pressu r e m e t e r all it takes to make the system inflate the arm cuff to the appropri- ate pressure. Electronics then auto- In Brief matically take measurements for The Omron HEM-711AC blood pressure monitor tracks an systolic and diastolic pressure, important health issue with reasonable accuracy and af- along with heart rate, and display fordability. Rather than lean on leading-edge technology, the data on a 2.5-inch liquid-crystal the product uses simple transducers and clever circuit de- display. The unit is powered by four sign to deliver an end system for about $60 retail. The AA alkaline cells or a supplied ac HEM-711ACs cost is driven as much by pneumatics and adapter. mechanics as by its electronics, which amount to little The HEM-711AC—along with most more than a capacitive sensor, quad-logic gate and MPU. other personal blood pressure mon- The design shows that clever engineering can hold its own itors sold—uses the “oscillometric” against brute-force technology alternatives. For those who technique for measurement. Oscil- appreciate simple elegance, its worth a look. lometric monitoring relies on the tracking of pressure oscillation pat- seems to be that it is good enough The rubber tube from the cuff en- terns in the cuff during its stepwise for general trend monitoring. ters the base unit and is plugged deflation. Proprietary algorithms Internally, the HEM-711AC con- into a pressure sensor mounted di- then translate observed fluctua- tains a motor-pump combination, an rectly on the circuit board. The same tions into systolic and diastolic electronically operated air pressure rubber hose is connected to the pressure values. release solenoid valve, the 2.5-inch pump and release valve, which han- While there has been much LCD, a single circuit board and air dle the pneumatics. debate about the technique’s useful- tubing to connect the pressurized The pressure sensor in this case ness to doctors, the consensus components. is a mechanical diaphragm that is57 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  57. Blood pressu r e m e t e r depressed in proportion to applied pressure. The deflected “drumhead” of the diaphragm forms one of two plates of what is effectively an air-di- electric capacitor, with a fixed plate Capacitive pressure sensor in the pressure sensor parallel to the movable plate. Pressure changes in the system correspond to shifts in the variable capacitor. The clever part is turning capaci- tance changes into useful data on the cheap. The precise details of im- plementation get a little fuzzy at this point, but trace-out of the circuit suggests that the variable capacitor (pressure sensor) is used to modify the frequency of a ring oscillator formed from the four gates in the Toshiba 74VHC02 quad NOR gate. microcontroller from Toshiba. either is used to drive the internal Wiggles in pressure correspond to Exactly what happens next in the algorithms, which determine a corre- wiggles in the ring-oscillator fre- microcontroller is also a little un- sponding systolic or diastolic pres- quency. The output is connected to clear, but some form of frequency sure value for display on the LCD. the monitor’s electronic workhorse: counter or frequency-to-voltage con- The Toshiba microcontroller drives the CK29U-3B53 a proprietary 8-bit version is presumed. The output of the LCD directly. It also controls the58 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  58. Blood pressu r e m e t e r user buttons, pump motor and air pressure release solenoid. A Seiko Instruments E2PROM, the S-29221, holds the limited amount of boot code needed. Toshiba #TC74VHC02F Detailed analysis of the product Quad 2-input pegs the manufacturing cost-of- NOR gate goods-sold at below $20, with a Ricoh roughly even split between electron- #RH5RL38A 3.8-V voltage ics and system mechanicals. regulator The simple elegance of the trans- (SOT-89 package) ducer/ring oscillator solution at the Toshiba heart of the HEM-711AC is critical to #CK29U-3B53 the low observed COGS. By the addi- 8-bit microcontroller + ROM tion of simple, inexpensive electron- ics around the sensing method, an important health-monitoring tool can be delivered to a mass consumer Seiko Instruments base at a nice profit. p #S-29221 2-kbit E2PROM59 E E T i m e s |The diagnosis for medical electronics | D e c e m b e r 7 , 2 0 0 9
  59. Inside the art of pulse oximetry By Patrick Mannion ew disciplines can turn the cold F science of metrology into pure art as quickly as medical diagnostics can. Its practitioners transcend the confines of biology, chemistry and physics, borrowing from each disci- pline—and stretching the limits of technol- ogy—first to divine what to measure, then to make the measurements and extract the desired information from the data. Masimo’s Radical-7 takes Transformation of the raw values into valu- blood analysis out of the lab able metrics requires the development and and into the field implementation of special signal-processing algorithms. By melding what is already60 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  60. P ulse oxime t r y known with carefully thought-out as- through its in vivo, noninvasive noninvasive analysis would allow sumptions that are based on years methodology would consider that a large numbers of people to be of research and experiential data, steal. The system can extract an ac- tested on site for carbon monoxide such algorithms often form the intel- curate signal even when the subject (CO) poisoning. lectual property heart of advanced di- is moving, and it is undaunted by “There’s no way to do it without a agnostic equipment. variations in bone density and skin device like ours,” said Sampath. Certainly, that holds true for pigmentation. “You’d literally have to take them to Masimo’s Radical-7 Signal Extrac- “It’s a no-brainer to take a vial a hospital and draw blood, and it tion Pulse-CO Oximeter. At the cross- of blood, put it in a test tube or would take hours [to get results]. roads of science cuvette, put that in a spectropho- Meanwhile the damage is done.” and art , the Radical-7 combines tometer and get [the desired] infor- Now, he said, “it’s something a patented signal-extraction algo- mation,” said Anand Sampath, guy in an ambulance can do.” rithms and advanced spectrographic Masimo’s executive vice president Sampath pointed to the ability of and signal-acquisition technology in of engineering. “Physicists and Masimo’s systems to monitor a mov- an efficient and intuitive design that chemists know how to do this on ing subject, compensating for the ar- takes blood analysis out of the lab the bench.” It’s another matter, tifacts that such movement and into the field, accelerating the Sampath said, “to do it in vivo, introduces. Invented by Masimo in time to diagnosis (and thus to treat- where the blood is actually pulsating 1996 (and covered in U.S. Patent ment). and you have all kinds of artifacts Nos. 6,263,222, 6,770,028, The Radical-7 weighs in at around and tissues.” 6,658,276, 6,157,850, 6,002,952 $6,000 in its baseline configuration, But there are times when in vivo 5,769,785 and 5,758,644, among rising to approximately $15,000 for testing is the best, and perhaps the others), this capability applies all the bells and whistles, but those only, option. In an office tower fire, across all situations but is particu- whose lives it has helped save for example, portable equipment for larly helpful in the case of prema-61 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  61. P ulse oximet r y ture babies, whose blood oxygen lev- els need constant monitoring but who are unlikely to remain still for the procedure. Until the advent of effective in vivo testing, such infants were sometimes given too much oxygen, causing retinopathy of pre- maturity (ROP); severe cases often resulted in blindness, according to Sampath. The company’s previous-genera- tion Radical pulse oximeter, based on Masimo SET (signal extraction technology) two-LED technology, could extract basic information such as arterial oxygen saturation, pulse rate and perfusion (pulse strength). The Radical-7 uses the company’s Rainbow SET seven-LED technology to enable the extraction of more advanced parameters, such as carboxyhemoglobin (to test for carbon monoxide poisoning), methemoglobin (to check for overdoses of painkillers such as62 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  62. P ulse oximet r y benzocaine and for poisoning from While the use of LEDs in such ap- saturation and pulse rate. Because chemicals such as nitrates) and plications is not new, Masimo has it is not bound by a conventional total hemoglobin, as well as oxygen advanced the technology with its “red over infrared” ratio approach, content and arterial oxygen satura- own design. the Masimo SET system greatly miti- tion. It also charts the pleth wave- The real innovation, however, is gates the problems of motion arti- form (heartbeat) and provides a the company’s signal extraction facts, low peripheral perfusion and pleth variability index. technology. most low signal-to-noise situations, The basic measurements and raw At the time of its introduction, SET allowing it to be used in low-signal, data are generated using well-trod- was a new and fundamentally dis- high-motion applications. den spectrographic principles of ab- tinct method of acquiring, process- How does one derive such a refer- sorption at different wavelengths, in ing and reporting arterial oxygen ence where none is present? “This this case using LEDs as the light saturation and pulse rate data. It is the fundamental problem we source. “We won’t discuss the spe- uses adaptive filters (widely de- solve with an algorithm called the cific wavelengths,” said Sampath, ployed in communications systems) Discrete Saturation Transform en- “but the two-LED [Masimo SET] sys- to accurately establish a “noise ref- gine, or DST engine,” said Sampath. tem has a visible LED and a near-IR erence” in the detected physiologi- All algorithms are based on as- [infrared] LED, whereas the Rainbow cal signal sent back from the sumptions. The higher the number [SET] has several visible LEDs and sensor. The reference allows the di- of assumptions, the weaker the al- several near-IR LEDs.” rect calculation of arterial oxygen gorithm. The DST engine makes only63 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  63. P ulse oximet r y one assumption, that arterial blood issue was finally put to rest in Janu- tion,” Sampath said. has higher oxygenation than venous ary 2006 when, after Masimo won Given the parameters of the de- blood does. the patent suit in both district and sign, with so much dependent upon Working from that single assump- appellate courts, the companies ar- accurate sensing of low-level signals tion, the DST engine allows the rived at a settlement agreement. and their back-end processing, the Masimo system to separate and con- Winning patent battles is one designers of the Radical-7 had their sequently calculate the optical den- thing, but the proof of a good algo- work cut out for them. They had to sity ratios that correspond to the rithm is in its efficacy—in this case, make wise design and component arterial oxygen saturation and esti- how accurate it is relative to estab- choices with respect to signal acqui- mated venous oxygen saturation. lished techniques. sition, conditioning, amplification, Those optical densities are not According to Sampath, in carboxy- conversion and, ultimately, a signal- known beforehand but are required to hemoglobin measurements, the processing platform. obtain the appropriate reference sig- Masimo system achieves accuracy nals for adaptive noise cancellation. of +/–3 percent, vs. +/–2 percent From theory to design The signal processing at the heart in the lab. For methemoglobin meas- Removing the top cover with its at- of Masimo SET proved so powerful urements, the window narrows to tached display and keypad exposes under patient motion conditions that +/–1 percent, “the same as with in- three boards, with the smallest, the it became central to a patent-in- vasive techniques,” he said. MX-1, on top. As always, size can fringement dispute between Masimo For hemoglobin measurement ac- be deceiving: It turns out the MX-1 and longtime competitor Nellcor. The curacy, the figure for the Radical-7 is contains almost all of the system’s 1 gram per deciliter (g/dL), vs. 0.5 secret sauce—everything from ana- The MX-1 contains almost all of g/dL in the lab. log inputs from the sensors to the the secret sauce, from analog “All of these are for 1 standard de- main signal processing. inputs to signal processing viation, or 67 percent of the popula- “These are very small physiological64 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  64. P ulse oximet r y signals—very sensitive to noise and ple on the planet, literally, simply be- The AD90801 is fed by an artifacts—so all the electronics, cause of the amount of attention AKM5355VT low-voltage, 16-bit from the sensor all the way through we’ve given to this topic,” he said. analog-to-digital converter and is to the signal processing, is all fun- At the heart of the MX-1 is the supported by Silicon Storage Tech- damentally new and proprietary,” signal-processing IC: the AD90801 nology’s SST34HF1621C Combo- said Sampath. custom ROM product from Analog Memory, which integrates 16 Mbits The signals being captured are Devices Inc. Sampath acknowl- of flash with 2 Mbits of SRAM. 10x to 100x smaller than those en- edged the device was based on a The AKM5355VT is a delta-sigma countered at the input of an RF Sharc-family processor from ADI converter originally intended for radio system, Sampath said, empha- but would not specify which one. sizing the importance of board lay- An online search of SEC and other out and good design practices in data, however, points to a digital maintaining signal integrity by ensur- signal processor from the ADSP- ing proper signal handling. 2136x line. But there’s more to it than that, Masimo’s designers chose that he added, noting that many compa- DSP because for their application, nies deal with signals in this range. “the most important function was For Masimo, it has more to do with performance, especially floating- having the technology necessary to point performance for the precision accommodate patients with varying that we needed,” said Sampath. At degrees of skin pigmentation, bone the time of the initial design, circa density, tissue scattering and so on. 2004-2005, the part in question “Because of our signal integrity, we was the best choice for the tasks at are able to work with the most peo- hand, he said.65 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  65. P ulse oximet r y audio applications, so it comes with ‘Because of our signal integrity, current-output DACs from ADI. an input gain amplifier, making it we are able to work with the most Also on the back are three ideal for the MX-1’s low-input signal SN74LVC573A octal transparent people on the planet, literally’ levels. The analog signal input of D-type latches from TI that feature the AK5355 is single-ended, elimi- tending below the negative rail. That three-state outputs designed specifi- nating the need for external filters. range lets the device accommodate cally for driving highly capacitive or That not only saves space and cost input signals below ground in the sin- relatively low-impedance loads. but also improves overall signal in- gle-supply mode, another prerequisite The output of the DSP is fed via a tegrity by narrowing the opportuni- for meeting the MX-1’s needs. 10-pin connector on the back of the ties for signal loss and interference. On the digital-to-analog conver- MX-1 to the main instrument board, The part is housed in a space-saving sion side, the main IC is ADI’s which performs the core operational 16-pin TSSOP . DAC8043AF, a high-accuracy 12-bit functions of a patient monitor, such Further down the signal chain, at multiplying DAC featuring serial as computation and display of the connector where the signals input, double buffering and 5-V measurement results, as well as from the sensor first enter the operation at less than 10 µA with a user-interface and other control board, is another critical IC: ADI’s 1-microsecond settling time. functions. Another Sharc shows AD820, a precision, low-power FET Control, housekeeping and other up here: the ADSP-21062L, a high- input op amp that amplifies the low- processing functions are performed performance signal processor origi- level signals from the sensor. The by Texas Instruments’ ultralow-power nally intended for communications, part can operate from a single sup- MSP430F169 16-bit microcontroller. graphics and imaging applications. ply of 5 V to 36 V, or from dual sup- The back of the MX-1 is mainly de- Having a high-end DSP on a board plies of +/–2.5 V to +/–18 V. It voted to driving the LEDs, in this that’s essentially geared for low-end features true single-supply capabil- case using a bank of eight control and minor processing func- ity, with an input voltage range ex- AD5449YRU 12-bit, dual-channel tions seems like overkill. Sampath66 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  66. P ulse oximet r y acknowledged that the choice here mitter (DUART) from NXP . HC32 quad two-input OR gate and didn’t have to be a Sharc and could Other logic on the top side of the an HC541 octal line driver. NXP con- have been any embedded-type board includes an Epson RTC72423 tributes its HEF4013BT dual D-type processor, but he added that since 4-bit real-time clock module with flip-flop. Masimo was already using the ADI built-in crystal, an NXP 7555CD gen- The third board on the Radical-7’s tools, “using it [the 21062L] on the eral-purpose CMOS timer, a Fairchild handset is the main display board, main board was more an artifact of Semiconductor LCX245 low-voltage driven by an Epson convenience.” bidirectional transceiver and a TI S1D13A04F00A1 LCD controller. Newer Masimo systems do, in HC163 4-bit synchronous binary fact, use a generic IC with an ARM counter. The HC163 features an in- Intelligent docking station core, but Sampath would not identify ternal carry look-ahead for high- The clean design of the docking sta- the device or its maker. speed counting. tion that charges the Radical-7 The DSP is supported by 16 Mbits The back of the control board in- handset seems straightforward at of single-die MirrorBit flash from cludes four TI HC595 8-bit shift reg- first blush, but Sampath pointed to Spansion (S29AL016D90TF102) isters with three-state output two key features. and 4 Mbits of low-power SRAM registers; two HC165 8-bit parallel- The first is the “flipping” screen, from Alliance (AS6C4008). load shift registers; one HC138 which switches to horizontal mode Next to those devices sits the three-line to eight-line decoder/mul- when the handset is attached to the SC28L92A1B, a 3.3/5.0-V dual uni- tiplexer; one TI HC163 4-bit binary docking station. This was initially ac- versal asynchronous receiver/trans- counter; and, from Fairchild, an complished using a gravity-detect67 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9
  67. P ulse oximet r y switch, but newer versions incorpo- of boot-sector flash from AMIC Tech- rate an accelerometer. nology (A29L008AUV) and 2 Mbits About the Author The second feature lets the Radi- of SRAM from Alliance Memory Patrick Mannion is editorial director of TechOnline. cal-7 connect to third-party monitors (AS6C2008). and regenerate the physiological sig- email: pmannion@techinsights.com nal. “Existing operating rooms al- FDA approvals ready have patient-monitor devices; As a medical system, the Radical-7 all they need is our technology,” said had to square with IEC as well as Sampath. Using a feature called FDA regulations. “When we intro- SatShare, the station can display duced this in 2005, we had to pass the captured measurements on all the leakage current, EMC and iso- third-party monitors, which in turn lation standards as part of IEC [certi- can be integrated into a hospital’s fication],” said Sampath. Masimo information management system. accomplished that by “sticking to This also allows patients’ physiologi- fundamentals” with respect to lay- cal measurements to go directly into out, ensuring that clocks had ade- their electronic medical records. quate ground plane protection and To do this, the docking station that trace paths for high-power sig- relies on yet another Sharc pro- nals were appropriately managed. cessor. This time it’s the lower-cost Despite Masimo’s system-design ADSP-21065L, a general-purpose, prowess, it’s worth noting that the programmable 32-bit DSP with fixed- company commonly licenses its or floating-point capability. The MX-1 technology to other medical 21065L is supported by 8 Mbits system manufacturers. p68 E E T i m e s |The future of medical electronics | D e c e m b e r 7 , 2 0 0 9

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