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JANUARY 19, 2000

Avoiding Technical Pitfalls in Medical Device Development

Geetha Rao, Ph.D.

In the race to commercialize and secure critical market share, medical device companies sometimes take the long road by making technical choices that have unexpected consequences. These include unexpected material behavior, component interactions that weren't supposed to happen, and interesting ways in which people use the device. Even initially successful devices can fall prey to the Law of Revealed Hazard Diversity (the more devices you sell, the more strange and amazing hazards will turn up). Using real-life cases, this talk will explore the various do's and don'ts on technical strategy during various stages of the business cycle of a medical device development effort. These are applicable to start-ups as well as large companies.

Dr. Geetha Rao is a Senior Managing Engineer at Exponent, an engineering and scientific consulting firm based in Menlo Park, California. She has over 13 years of experience working on risk and quality management and has helped numerous medical device companies with strategic technical issues. Her focus has been on helping companies find the right balance between thoroughly studying the risks and uncertainties and producing commercial products in a timely and cost-effective manner. She has been actively involved in developing new approaches to risk management and is a member of the AAMI Application of Risk Management to Medical Devices Working Group, which serves on the US Technical Advisory Group on ISO/TC 210, the technical committee on quality management and corresponding general aspects for medical devices. Dr. Rao holds a doctorate in engineering from the Massachusetts Institute of Technology and a master's degree in management from Stanford University's Graduate School of Business.

FEBRUARY 16, 2000

Opal Photoactivator & Visudyne Therapy for the treatment of Age Related Macular Degeneration

Dennis Dowell
Coherent Medical Group

Age Related Macular Degeneration (AMD) is a degenerative condition of the macula, the part of the back of the eye that provides clear, central vision. Central vision is needed every day for activities such as reading and driving. There are two forms of AMD: wet (neovascularization) and dry (atrophic). Dry AMD develops slowly (over a number of years) and usually only causes mild vision loss with the primary symptom being a dimming of vision when reading. The wet form of AMD (neovascular) is caused by the growth of abnormal blood vessels across the macula. These abnormal vessels leak fluid and blood into the tissue at the back of the eye, causing impairment of central vision. While wet AMD accounts for 15% of all cases, it is responsible for 90% of the severe vision loss associated with AMD. The current primary treatment option for wet AMD, laser photocoagulation, is available for only a few and outcomes for the patient are less than positive. Photocoagulation is limited because it destroys healthy retinal tissue along with tissue affected by AMD and patients pay the price of an immediate loss of visual acuity following treatment in return for slower disease progression. In addition, half of patients treated with laser photocoagulation suffer from recurrences.

Visudyne Therapy involves the use of a light-activated compound called verteporfin combined with a non-thermal laser to produce a therapeutic effect. The non-thermal laser used is the new Coherent Opal Photoactivator. Treatment consists of a two-step process beginning with administration of the drug, or "photosensitizer", by intravenous injection. While circulating in the bloodstream, the drug attaches to molecules called lipoproteins. Because neovascular cells require a greater amount of lipoproteins than non-dividing cells, the drug is delivered more quickly and in higher concentrations to these types of cells. It is then activated with a pre-calculated dose of light at 689nm. The activated drug subsequently causes the conversion of normal oxygen found in tissue to a highly energized form called "singlet oxygen". The singlet oxygen, in turn, causes cell death by disrupting normal cellular functions. Neither the drug nor the light exerts any effect until combined. Because the light is shone directly at the targeted tissue and the drug accumulates preferentially in these cells, photodynamic therapy results in a highly selective treatment.

Dennis Dowell, MFA, MS has been working in Ophthalmology since 1983 when he began doing Ophthalmic photographic research at USC Estelle Doheney Eye Foundation. After several conceptual product designs, he moved into product design and management for Nidek Incorporated (Fremont Ca.). He then moved to Humphrey Systems (Dublin Ca.) as Marketing Manager. He is now the the Marketing Manager of the Ophthalmic business unit at Coherent Medical Group.

MARCH 15, 2000

Applications of X-band Technology in Medical Accelerators

S. M. Hanna
Siemens Medical Systems-OCS

Most radiation therapy machines are based on microwave linear accelerators. The majority of medical accelerators use frequencies in the S-band range. Having a compact accelerator allows for a wide range of treatments. The size and weight of the accelerator is substantially reduced if a higher frequency is used. X-band frequencies are suitable for such applications. X-band accelerator technology has been used in high-energy physics experiments as well as industrial applications. In the radiation therapy field, it is already implemented in some machines. The Mobetron, an Intra-Operative Radiation Therapy (IORT) treatment system, is one example. Another example is the Stereotactic Radiosurgery machine, the CyberKnife. The compactness of these machines required the use of an X-band accelerator. The basis for choosing the X-band technology in some of the medical machines will be analyzed. A review of the exiting medical applications will be discussed.

Dr. Samy Hanna obtained his graduate degrees from Caltech and Purdue University. He started his career as an Assistant Professor at Polytechnic University (formerly Brooklyn Polytechnic) in Long Island, N. Y. He was promoted to Associate Professor in 1988. He moved to California in 1994 to join Stanford University- SLAC to work on X-Band accelerators for high-energy physics experiments. He is currently a Principal Engineer at Siemens Medical Systems Inc. (Oncology Care Systems Group) working on medical accelerators.

APRIL 19, 2000

Native Tissue Harmonic Imaging: What it Does and How it Works

Chuck Bradley
Acuson Corporation

One of the oldest and most tenacious imaging artifacts known to users of ultrasound is the clutter that is present in the images obtained during the scanning of what are known as 'technically difficult' patients. This image clutter has long been known to be due to the fact that different tissues have different acoustical properties. Some 20-30% of patients referred to ultrasound imaging belong to this 'technically difficult' category, and in many cases these patient must in turn be referred to another imaging modality, such as MRI, or possibly to an invasive procedure.

Since the recognition of the cause of clutter there have been numerous attempts to make use of adaptive focusing schemes to compensate for the tissue-induced aberration and therefore to reduce image clutter. No such schemes have yet proven to have any practical viability.

On an apparently unrelated front, it has also long been known that high intensity sound becomes progressively more and more distorted as it propagates. This process is known as nonlinear acoustic propagation distortion, and it results in the generation of frequency components that were not present at the source. Among these frequency components is the second harmonic component. It turns out that the field levels used in conventional diagnostic ultrasound are sufficiently high that images may be formed using this second harmonic distortion component instead of the normally-used fundamental. It also turns out that the resultant images exhibit remarkably reduced clutter levels. This is a previously unknown property of nonlinear acoustic propagation distortion: components of the transmitted field exhibit a reduced susceptibility to aberration and reverb.

Ultrasound imaging based on this phenomenon is known as tissue harmonic imaging, and has had a dramatic impact on the day-to-day use of diagnostic ultrasound. It proves to be a remarkably effective, elegant, and straightforward way of making ultrasound a more broadly effective imaging modality.

The talk is intended to be a comprehensive overview of tissue harmonic imaging. Included will be discussions of the fundamental physical mechanisms of nonlinear acoustic propagation distortion, the mechanism by which such distortion results in a reduced susceptibility to aberration, and implementation issues. A video tape showing a number of scanning sessions will also be shown.

Dr. Charles E. Bradley, B.S., M.S., PhD, has been working in the field of nonlinear acoustics for 13 years. He has a number of publications on the topics of nonlinear acoustic Bloch wave propagation, acoustic streaming, and micromachined acoustic flexural plate wave devices. He is currently a fellow at Acuson Labs, a research division of Acuson Corporation, which is a leading manufacturer of diagnostic medical ultrasound systems.

MAY 17, 2000

The Intravascular SONOTHERAPY System for the Prevention of Restenosis within Stents

William Nowlin, Ph.D.
Intuitive Surgical, Inc.

With the recent adoption of minimally invasive techniques, surgeons have been able to dramatically reduce the size of incisions and improve postoperative recovery. However, this transition in technique has required surgeons in a number of specialties to use long, awkward instruments that lack the precision, control, and ease of use of conventional tools. In attempting to extend the use of standard minimally invasive instrumentation into vascular surgery, it is clear that these tools lack the dexterity and precision necessary to be clinically useful.

The use of telemanipulators in surgery offers the ability to return to instinctive control, precision and dexterity to minimally invasive technique by electronic translation of surgeon movement from outside the body to inside the body. Telemanipulation allows the surgeon to use open surgical technique in al minimally invasive format while electronically enhancing his or her movements for greater accuracy.

Development of telemanipulators that provide maximum clinical utility involves the integration of mechanical, electrical and software engineering to translate instinctive surgical hand movements at a console to similar movements at the tip of an instrument driven by servo-motors. Intuitive Surgical Inc., in the past four years, has developed a telesurgical system which attempts to deliver this capability to the mainstream of surgical practice. To date, a seven-degree of freedom master/slave telemanipulator system has been developed, which can very efficiently suture small vascular structures as well as accomplish fine dissection and tissue manipulation. Human clinical experience has been extensive, with procedures performed in cardiac, generalgynecological, urologic and vascular surgery.

Intuitive has shipped more that twenty-five systems worldwide and robotic surgery has become the standard of care in a number of hospitals. Surgical telemanipulation is becoming a powerful new tool in the armamentarium of the surgeon and will have a major impact in enabling minimally invasive technique across surgical specialties.

Dr. William Nowlin joined Intuitive Surgical in 1996, were he helped create the control and performance algorithms and other core technology for the daVinci Surgical System, and more recently has led the group responsible for analyzing overall system performance. He came to Intuitive from SRI International, were he developed applications for linear control design and consulted on the telesurgery work that was spun off to form ISI. Dr. Nowlin received his Ph.D. in Applied Mathematics (tactile sensing for compliant robotic manipulators) from Harvard University in 1991, under the tutelage of Prof. Roger Brockett.

JUNE 14, 2000

Assistive Technology for Persons with Disabilities

David L. Jaffe
VA Rehabilitation Research and Development Center

The Rehabilitation Research and Development Center at the Palo Alto VA Health Care System is dedicated to developing innovative clinical treatments and assistive devices for veterans with physical disabilities to increase their independence and improve their quality of life. The focus of the Center's research is to improve mobility - ambulation and manipulation - in persons with neurologic or orthopaedic impairments. Projects target four conditions that cause significant loss of mobility to veterans as well as non-veterans: stroke, spinal cord injury, arthritis, and osteoporosis. Investigators are involved in the design, development, testing, and clinical assessment of new diagnostic approaches, treatments, functional assessment methods, assistive devices, and therapeutic techniques.

This presentation will focus on the Center's projects, other rehabilitation research, and commercially available products that serve the mobility, communication, and therapeutic needs of people with disabilities. Specific Center projects include a powered wheelchair controlled by head position, a mechanical hand that helps deaf/blind people communicate, a virtual reality training project, a wearable data acquisition system for balance assessment, an instrumented tilting bicycle ergometer, a robotic therapy device, and a reduced gravity treadmill system. Other rehabilitation research topics to be discussed are use of robots in human service applications, artificial eyes, and brain implants. The commercial products to be highlighted are a graphically based communication system, a balancing wheelchair, and alternate means of operating a computer.

David L. Jaffe has been a research biomedical engineer at the VA Rehabilitation R&D Center for the past 20 years. His projects have included communication systems and alternative interfaces for people with disabilities. His expertise includes embedded computer system hardware and software design and development. He has a Bachelors degree in Electrical Engineering from the University of Michigan and a Masters degree in Biomedical Engineering from Northwestern University.

SEPTEMBER 20, 2000

An End to Needles: Pulmonary Delivery of Macromolecules

Dr. Carlos Schuler
Inhale Therapeutic Systems

Millions of Americans who must daily inject a dose of insulin will soon have an option: They may inhale insulin powder. The system developed by Inhale Therapeutic Systems blows a stream of compressed air through a bed of powder, creating a white cloud of tiny insulin particles. In clinical trials, the inhaleable drug has proven as effective as injected insulin. Inhale expects to obtain FDA market approval for its delivery system in the next few years.

Dr. Carlos Schuler, from Inhale Therapeutic Systems, will discuss how Inhale has created a synergy between powder processing, packaging and medical device technologies to develop this new non-invasive medication delivery system. The system offers painless, efficient, reproducible, deep-lung drug delivery of proteins, peptides and other macromolecules.

The talk will focus on these technologies from an engineering perspective. The system Inhale has created through this technology synergy is applicable to a large variety of protein and peptide drugs.

Dr. Carlos Schuler received his B. Sc. (1983) and M. Sc. (1985) degrees in mechanical engineering from Universidad Simon Bolivar in Venezuela, and his Ph.D. (1990) degree in mechanical engineering from the University of California at Berkeley. After graduation, Dr. Schuler held a postdoctoral position there, funded by IBM Almaden Research Center to investigate the aerodynamics of magnetic storage devices, hard disks in particular. In 1991, Dr. Schuler accepted a Scientist position at Aerometrics, Incorporated. At Aerometrics, Dr. Schuler's focus was on the development of electro-optical diagnostics with applications to aerodynamics, atomization, two-phase flow research, and Intelligent Vehicle Highway Systems. In 1997, Dr. Schuler accepted the position of Technology Development Engineer at Inhale. Dr. Schuler is currently Associate Technical Director, responsible for establishing and coordinating Inhale's R&D efforts in the area of next generation device technology.

OCTOBER 18, 2000

Bringing Safe Medical Products to Worldwide Markets

Bryan Blair
Underwriters Laboratories Inc.

Today, most manufacturers of medical devices desire to sell their products in markets all over the world, requiring them to meet a variety of regulatory (legal) and purchaser (buyer) requirements. This presentation will focus on the underlying risk assessment principles behind most regulatory requirements, including the United States (FDA) and Europe (Medical Device Directive). In addition to general principles, protection against the risk of electric shock hazards will be discussed in detail. Specifics will include key terms from ISO 14971 (Application of Risk Management to Medical Equipment), electric shock hazard fundamentals, requirements from IEC 60601-1/UL 2601-1 (Medical Electrical Equipment, Part 1: General Requirements for Safety), leakage current measurements, insulation requirements, and other safety hazards.

Bryan Blair is Engineering Group Leader at the Santa Clara Underwriters Laboratories Inc. (UL) Medical Services Group. He has ten years of experience evaluating medical equipment for UL, and is an instructor for UL's Designing for Compliance to IEC 60601-1/UL 2601-1 technical seminar. He has a BSEE degree and is currently working on an MBA.

NOVEMBER 15, 2000

Hearing Aid Design : Fundamentals and Challenges

Adnan Shennib
InSonus Medical

Hearing aid technology has advanced rapidly over the past two decades both in electronic and cosmetic aspects. Technological advances have resulted in a range of innovative products from miniature canal hearing aids to middle ear implants. Despite these advances, industry reports indicate that market penetration has declined during the same time period. This presentation examines some of the limitations of current technology in consideration of the psychoacoustic characteristics and needs of the hearing impaired. Fundamental issues in hearing aid design will be reviewed as well as paradoxical design constraints facing hearing aid engineers. An audio demonstration of various electroacoustic effects will be presented. New directions in hearing aid developments will also be discussed, time permitting.

Adnan Shennib, President & Founder of InSonus Medical, is an executive with 15 years experience in start-up and technical management of medical device companies. Mr. Shennib developed key technologies and over 25 inventions for local Bay Area firms including ReSound Corp. and Decibel Instruments, Inc. More recently, he founded InSonus Medical, Inc., a venture-backed firm developing the world's smallest hearing aid products weighing less than 1 gram. These totally invisible and minimally invasive products combine implant technology with high fidelity audio to produce ultra-low power hearing aids for extended wear. Mr. Shennib holds a B.S. in Electrical Engineering and M.S. in Biomedical Engineering.

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