bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytology, Automated
Authors: Tyrer Harry W.
Published: April 2006

The goal of automated cytology is to identify and classify cells. This requires a multidisciplined approach in which engineers, physicist, and computerists interact with biomedical scientist and clinicians. Currently a cell can be described in terms of its function (what it does) and its appearance under the microscope (morphology). Automated cytology begins by measuring features to determine a cell’s morphology or function. By far this is done with either absorption or fluorescent materials that attach to cellular compounds. Other detection strategies include current flow through cells, optical polarization from cellular molecules, acoustic energy absorption, and other electromagnetic and spectroscopic means. These detection systems have been placed into two main types of instrumentation that can be easily classified as low resolution (high cell throughput) and high resolution (low cell throughput) systems. The low resolution systems suspend cells in medium, which then flow past a detector’s field of view. A few features are collected on large numbers of cells, providing substantial statistics on the population of cells under consideration. An interesting set of variations includes sorting of specific subpopulations and even sorting of individual cells. These systems support data analysis of cells, which includes forming histograms, cluster analysis, modeling of specific types of histograms, and so on. High resolution systems consist of a microscope connected to a computer. Typically a light detector reads light intensities obtained by scanning the cell, and operations take place on the scanned cell. Data analysis can be used to identify important features of cells. Currently, there are a number of applications for these systems including medical diagnosis, basic immunology research, hematology and oncology, to name a few areas. The future for automated cytology is open since these systems provide objective data on the cells, are useful in diagnosis and treatment evaluation, save time, and provide new information.
Drug Infusion Systems
Authors: Ozcelik Selahattin
Published: April 2006

Drug infusion systems are being extensively used in hospitals as well as in home therapies. Device‐based drug delivery systems are used in a wide range of pharmacological therapy and can be classified as injection–infusion systems, transdermal patch‐based systems, and inhalation systems. These devices range in complexity from simple manual gravity drippers to fully automated sophisticated complete infusion systems. Contributions of engineering, basic sciences, and technological advancements have significantly improved drug administration in patients and have significantly eliminated medication errors due to users. This article focuses on the injection–infusion systems, reviews basic types and operational principles of these systems, and presents recent developments and advancements.
NeurologicalEEGMonitors: A Review
Authors: Gharieb R. R. , Thakor N. V.
Published: April 2006

This article presents a brief review of neurological monitors. Neurological monitors mainly utilize brain wave activity, namely, the electroencephalogram (EEG). The constituent components of the neurological monitor are the electrodes, amplifiers, analog‐to‐digital converter (ADC), and the monitoring display. Moreover, the monitor should provide digital storage and a readout of the ongoing EEG. Neurological diagnostic monitoring is accomplished using quantitative EEG analysis for assessment of the ongoing brain activity. The software of the monitor is designed to acquire and filter the raw EEG signal, remove artifacts, process the artifact‐free EEG signal, and utilize quantitative analysis of EEG to interpret neurological status of the brain. As such, the EEG monitors can be classified into two main categories based on their use in data monitoring and display and their use in providing quantitative EEG measures derived for assessment and tracking of the brain electrical activity in disease and brain injury. Several quantitative EEG (qEEG) analysis methods used in the more advanced diagnostic devices are reviewed. The article conclude by describing the most common specifications of an optimized monitor.
Electrocardiography, Computers in
Authors: Nazeran Homer
Published: April 2006

This article starts off with an attempt to present a distilled overview of the origin of bioelectric signals in general, and the electorcardiographic signal in particular. This overview sets the basis to briefly describe the cardiac vector and its projection along specific directions (leads) providing the surface ECG recordings and review the basic instrumentation necessary to record these signals. A detailed description of a high end computer‐based 12 lead clinical ECG acquisition and analysis system provides an example to appreciate the role of computers in diagnostic electrocardiography. An overview of the role of computers in high resolution electrocardiography (body surface potential mapping) and other ECG‐based diagnostic devices then follows. A brief introduction to computer‐based ECG monitoring systems and a block diagram description of a QRS detection algorithm illustrate how computer programming serves as a basis to detect cardiac arrhythmias. The article ends with a web‐based ECG telemonitoring system as an example.
Electroencephalography
Authors: Sherman David , Walterspacher Dirk
Published: April 2006

The following section will give an overview of the electroencephalogram (EEG), its origin, and its validity for diagnosis in clinical use. Since Berger demonstrated in 1929 that the activity of the brain can be measured using external electrodes placed directly on the intact skull, the EEG has been used to study functional states of the brain. Although the EEG signal is the most common indicator for brain injuries and functional brain disturbances, the complicated underlying process, creating the signal, is still not well understood.

The section is organized as follows. The biophysical basis of the origin of the EEG signal is described first, followed by EEG recordings and classification. Afterward, the validity and scientific basis for using the EEG signal as a tool for studying brain function and dysfunction is presented. Finally, logistical and technical considerations as they have to be made in measuring and analyzing biomedical signals are mentioned.
Electroneurography
Authors: Sinkjær Thomas , Yoshida Ken , Jensen Winnie , Schnabel Veit
Published: April 2006

An essential part in the success of recording peripheral nerve signals is the neural interface. This article gives the theoretical basis of how the action potential in a nerve is generated, and how this, in turn, results in a change in the electric field in the extracellular space. These potentials can be detected using neural interfaces (electrodes) in mono‐ to multipolar recording configurations to maximize the neural signal detected and minimize the noise pickup. These configurations are discussed along with a characterization of the recorded electroneurogram (ENG). Whether the ENG signals are recorded from extrafascicular or intrafascicular neural interfaces, it can be seen that ENGs are low amplitude signals and require amplification of between 1000X and 100,000X to bring the amplitude into the ∼ 1 V range. Electrode impedance models are derived to illustrate how the common mode rejection ratio (CMRR) of an ENG amplifier is influenced by frequency depended impedances.

Peripheral neural electrodes can be grouped according to the way that they interface with the peripheral neural tissue. The three main groups are regenerating, intraneural, and extraneural electrodes. Common for all electrode interfaces presented here are that they record the extracellular potential from one or many peripheral nerve axons simultaneously.

This article concludes with a section on recent studies performed with chronically implanted nerve cuffs in animal models and disabled human subjects. Exmples are presented of the potential value of peripheral nerve recordings to furnish sensory information for feedback control in fully implantable neuroprostehsis systems.
Electrophoresis
Authors: Brewer John M.
Published: April 2006

Electrophoresis involves application of an electric field to solutions of ions, causing them to move. The aim is to separate charged molecules, particularly proteins and polynucleotides. Better separation may result from use of electrophoretic characteristics of different small ions (mobilities), from use of materials employed to prevent convective disturbances (support media), or higher voltages. Successive electrophoresis in two directions under different conditions on sheets of support media can resolve thousands of proteins. Electrophoresis in the presence of an ionic detergent is used to obtain protein subunit molecular weights. Electrophoretic separation of polynucleotides varying in length by one nucleotide is the basis of DNA sequencing. Clinical use of electrophoresis is for diagnostic purposes.
Electroretinography
Authors: Holder Graham E.
Published: April 2006

Electroretinography (ERG) objectively evaluates the function of the photoreceptor and inner nuclear layers of the retina by measuring the small electrical signals generated in response to controlled flashes of light. The stimuli are delivered via a Ganzfeld bowl, an integrating sphere, and are recorded using small electrodes in contact with the surface of the eye.

Manipulation of the adaptive state of the eye and variation in stimulus parameters enables separation of the function of different cell types and layers. In general, responses obtained under dark adaptation (scotopic) are rod‐dominated and those under light adapted conditions (photopic) are cone dominated. The function of the macula, the cone‐rich central area of the retina, can be quantified with the pattern electroretinogram (PERG, the response of the retina to a black and white reversing checkerboard or grating), which also, in relation to its inner retinal origins, enables retinal ganglion cell function directly to be ascertained. Assessment of central retinal cones can also be performed with multi‐focal ERG, which additionally provides spatial information.

The basics of recording electroretinographic signals are discussed, and the importance of performing all tests to published international standards is noted. An overview is presented of the value of the tests to the diagnosis and management of the patient.
Environmental Control
Authors: Anson Denis
Published: April 2006

Electronic aids to daily living (EADLs) are devices that can be used to control electrical devices in the client's environment. Before 1998, these devices were generally known by the shorter term, “Environmental Control Unit” (ECU). Technically, this term should be reserved for furnace thermostats and similar controls. The more generic EADL applies to control of lighting and temperature, but also applies to control of radios, televisions, telephones, and other electrical and electronic devices in the environment of the client.

These systems all contain some method for the user to provide input to the EADL, some means of determining the current state of the device to be controlled (although this is often visual inspection of the device itself, since EADLs are generally thought of as being applied to the immediate environment), and a means of exerting control over the targeted device. The degree and generalization of control differs among various EADL systems. These systems may provide a means of switching power to the target device, of controlling the features of an external device, or may subsume an external device to provide enhanced control internally.
Equipment Acquisition
Authors: Stiefel Robert
Published: April 2006

The scope of this article is limited to the justification, selection, and implementation of new medical technology and equipment (Table

). It is not intended to provide cookbook methods to be followed exactly, but instead to explain principles that can be applied to different hospitals and their differing needs. This seems to be particularly appropriate because needs vary not only between hospitals, but also with time.
Equipment Maintenance, Biomedical
Authors: Subhan Arif
Published: April 2006

This article reviews the history and background of equipment maintenance in medical applications and discusses the preventive maintenance process surrounding biomedical equipment.
Esophageal Manometry
Authors: Velanovich Vic
Published: April 2006

Esophageal manometry measures pressures of the intraesophageal space. These pressures are reflective of the function of the esophageal musculature. The structures primarily assessed are the upper esophageal sphincter, the esophageal body, and the lower esophageal sphincter. The device measures pressures through either a water‐perfused or solid‐state catheter connected to a pressure reading instrument. The device measures lower esophageal sphincter pressure, length, and relaxation; esophageal body contractions, coordination, peristalsis, and peristaltic pressure amplitudes; and upper esophageal pressure and relaxation. Esophageal manometry is useful in the assessment of dysphagia, gastroesophageal reflux disease, generalized diseases with esophageal manifestations, and the exclude esophageal disease in patients with anorexia nervosa.
Fetal Monitoring
Authors: Neuman Michael R.
Published: April 2006

Fetal monitoring is a special type of electronic patient monitoring aimed at obtaining a record of vital physiologic functions during pregnancy and birth. Such monitoring is applied in assessing the progress of pregnancy and labor, and it can identify conditions that concern the clinician caring for the patient. These nonreassuring recordings can lead to special considerations in caring for the pregnant patient and in managing her labor. Although these recordings are no longer considered to be definitive in identifying most forms of fetal distress, they can help to reassure patient and clinician that the fetus is able to withstand the physiologic stress of labor and delivery. The technology is also useful in assessing high‐risk pregnancies, which in most cases, is only reassuring as opposed to giving a definitive diagnosis. Although this technology is now recognized to have diagnostic limitations, it is still frequently used in the hospital and clinics as an adjunct to other diagnostic evaluations.
Fiber Optics in Medicine
Authors: Modell Mark D. , Perelman Lev T.
Published: April 2006

The goal of this article is to give the reader basic tools necessary to understand principles of biomedical fiber optics and its applications. In addition to diagnostic, imaging, and therapeutic applications that are described in this article, optical fibers have been employed in a number of biomedical applications, for example, laser surgery and fiber‐based transducers for monitoring physiologically important parameters (temperature, pressure, oxygen saturation, blood flow). All those subjects have been covered in detail in the dedicated articles of this encyclopedia.

The structure of this article is the following. The first section provides general physical and engineering principles of fiber optics needed to understand the rest of the article. It discusses the physics of total internal reflection and throughput, fiber propagation modes, optical fiber construction, and types of fibers. The next section provides the reader with the review of illumination applications of fibers in medicine. The third section discusses the diagnostic applications of the biomedical fibers, including imaging and spectroscopy. The last section reviews therapeutic applications of fibers.
Cardiac Output, Fick Technique for
Authors: Faddy Steven C.
Published: April 2006

Cardiac output (CO) is an important measurement in many medical investigations. It is the amount of blood pumped by the ventricles of the heart and can be defined as the product of stroke volume (SV) and heart rate (HR), where stroke volume is the amount of blood expelled by the ventricle with each contraction and the HR is the number of contractions per minute.

Cardiac output gives an indication of ventricular function and is also used in the calculation of a number of flow‐dependent parameters, such as cardiac index, systemic vascular resistance, pulmonary vascular resistance, valve areas, and intracardiac shunt ratios.

The Fick technique is the gold standard in CO measurement. It relies on direct measurement of oxygen consumption and expenditure to derive the rate of blood flow throughout the individual.
Flowmeters, Electromagnetic
Authors: Fontaine Arnold A. , Deutsch Steven , Manning Keefe B.
Published: April 2006

Fluid flow occurs throughout biomedical engineering ranging from air flow in the lungs to diffusion of nutrients through membranes and involvesin vivoandin vitromeasurements. Flows involve fluid media in the form of gas, liquid, or multiphase flows of both liquids and gas together or in combination with solid matter. They can involve relatively benign flows like that of saline through an intravenous tube to a biochemically active flow of a nonNewtonian fluid such as blood. Many biomedical or bioengineering processes require the quantification of some flow field that may be directly or indirectly related to the process. Such quantification can involve the measurement of volume or mass flow, the static and dynamic pressures, the local velocity of the fluid, the motion (speed and direction) of particles such as cells, the flow‐related shear, or the diffusion of a chemical species.
Fluorescence Measurements
Authors: Klebe Robert J. , Zardeneta Gustavo , Horowitz Paul M.
Published: April 2006

Fluorescence measurements can be used to detect a large number of compounds with a sensitivity rivaling that of radioisotopic methods. In addition to sensitivity, fluorescence analysis provides a means to identify compounds, and determine the concentration of a given compound in a complex mixture. Such analyses can be carried out under nondestructive conditions. This article presents an overview of the theoretical basis of fluorescence spectroscopy as well as a discussion of technical considerations involved in several practical applications of this analytical method.
Bladder Dysfunction, Neurostimulation of
Authors: Hassouna Magdy , Elmayergi Nader , AbdelHady Mazen
Published: April 2006

This article discusses how the stimulation of the bladder, the pelvic floor and nerve, the detrusor, the spinal cord, and the sacral root affect bladder dysfunction. New systems for treatment and future directions are also discussed.
Heart Valve Prostheses
Authors: Chandran K. B.
Published: April 2006

Heart valve prostheses have been successfully implanted in humans with diseased native heart valves for >40 years. Patients with implanted prostheses lead a relatively normal life. The currently available prostheses can be broadly classified into mechanical and biological heart valve prostheses. Mechanical valve prostheses are made entirely out of blood compatible nonbiological material, and hence are highly durable. However, thrombo‐embolic complications are still the major problem with these valves, and hence the patient has to be under long‐term anticoagulant therapy. Biological valves with leaflets made of biological tissue generally do not require long‐term anticoagulant therapy. However, they lack in durability with replacements becoming necessary at 10–12 years after implantation on the average. It is clear that further improvements are needed in the valve designs in order to improve the quality of life for patients implanted with valve prostheses. This article discusses the history of development of valve prostheses, mechanical and bioprosthetic valves currently available for implantation, and efforts in our understanding of the relationship between the dynamics of valve function and the problems existing with the current valve prostheses.
Hyperbaric Oxygenation
Authors: Whelan Harry T. , Niezgoda Jeffrey A. , Lewis Matthew C. , Kindwall Eric P. , Cabigas Bernadette
Published: April 2006

Hyperbaric oxygen (HBO) is simply the delivery of molecular oxygen in very high dosage. Even though experience has shown HBO to be very useful in a number of conditions, the exact mechanism of action at the molecular level is not fully understood. This article reviews the various studies and results of HBO since its inception.
Hyperthermia, Interstitial
Authors: Sherar Michael D. , Chin Lee , Kumaradas J. Carl
Published: April 2006

Interstitial hyperthermia or thermal therapy is a minimally invasive method for the treatment of cancer. Radio frequency (RF), microwave, laser light, or ultrasound energy is delivered through one or more thin needle devices inserted directly into the tumor.
Hyperthermia, Ultrasonic
Authors: Patel Dimpi , Lakkireddy Dhanunjaya , Natale Andrea
Published: April 2006

This article compares and contrasts electromagnetic waves to ultrasonic waves as a heating modality, explains the physics behind ultrasound generation, and explores the thermal and mechanical biophysics involved with ultrasound delivery to tissue. Then, the medical fields that are currently benefitting from conventional ultrasound hyperthermia and HIFU are considered, and finally some of the many applicators involved with thermal ultrasound delivery are evaluated.
Impedance Plethysmography
Authors: Hutten Helmut
Published: April 2006

The term impedance plethysmography is commonly used in medicine to denote the estimation of a volume by measuring certain passive electrical properties of biological tissues. Since the first research work about these electrical properties about one century ago, both the technologies and the methodologies have expanded in a large number of different directions. Most of the diagnostic applications in medicine are patient‐near with the device directly connected to the patient. However, the number of applications in the field of laboratory medicine is steadily increasing. Although not all described bioimpedance‐based plethysmographic methodologies have actually found broad application in clinical routine, there is still the challenge to improve and to further evaluate technologies and methodologies, and to identify new fields of application.
Incubators, Infant
Authors: White Robert
Published: April 2006

Infant incubators were first developed to keep ill or preterm infants warm. Because the human infant is more complex than, say a chicken egg, and because much more intervention occurs with an ill infant than with the egg, incubators have become very sophisticated devices. In addition, the incubator is now often used as a delivery device for oxygen and humidity, as the platform for a number of other devices to support the ill newborn, and as a mechanism to control sensory stimuli to the developing brain. As these functional demands have increased, so has the mechanical complexity of the infant incubator. This article reviews the historical and scientific foundations of incubator design, and then describe some of the mechanical strategies used to respond to these functional demands of the present generation of infant incubators.
Intrauterine Surgical Techniques
Authors: Bruner Joseph P. , Wilson R. Douglas , Adzick N. Scott , Wilkins‐Haug Louise , Marshall Audrey C. , Quintero Ruben A. , Yamamoto M. , Ville Y. , Johnson Anthony , Moldenhauer Julie S.
Published: April 2006

Intrauterine surgery of the fetus or fetal adnexae is spreading rapidly throughout the world. In a broad sense, intrauterine surgery includes any procedure in which a medical device is purposely placed within the uterine cavity. For most physicians, however, the concept of intrauterine surgery excludes such commonly performed procedures as amniocentesis and chorionic villous sampling. Rather, the term usually refers to techniques requiring specialized knowledge, experience, and most especially, instrumentation. Procedures most commonly mentioned in discourses on intrauterine surgery include those specifically developed for the treatment of such serious anatomic defects as congenital cystic adenomatoid malformation (CCAM), sacrococcygeal teratoma (SCT), lower urinary tract obstruction (LUTO), myelomeningocele, aortic or pulmonic stenosis, gastroschisis, iatrogenic amniorhexis, twin‐to‐twin transfusion syndrome (TTTS), and twins discordant for severe anomalies. As no one person in the world is an expert in every one of these procedures, the remainder of this chapter is divided into individual sections, each authored by someone widely recognized as a leader in the treatment of that particular anomaly.
Joints, Biomechanics of
Authors: Papaioannou George , Yeni Yener N.
Published: April 2006

Bones in the skeleton join to form segments or links that provide for the attachment of muscles, ligaments, tendons, and so on. Altogether, these systems of bones and soft tissues, called joints, produce movement for the organism. Joint biomechanics traditionally is a division of biomechanics that studies the effect of forces on the joints of living organisms. Like all other organs, joints are subject to trauma and disease. Development of treatments, devices and exercise regimes for healthy joints, as well as learning from the great variety of naturally existing joints for the purpose of nature‐inspired technology, requires a fundamental understanding of the mechanics of joints and joint tissues, and their interaction with the underlying biological mechanisms. At the current state of the art, the definition of joint biomechanics can be broadened to encompass these complex interactions and the relevant technology. It is the purpose of this article to introduce a current understanding of joint biomechanics with an emphasis on the structure, kinematics, kinetics, modeling and joint stability of human joints. A detailed consideration of the mechanics of artifical joints and that of the tissues forming a joint is left for other articles.
Laryngeal Prosthetic Devices
Authors: Belforte Guido , Carello Massimiliana , Bongioannini Guido , Magnano Mauro
Published: April 2006

Larynx is a complicated organ strategically located at the division of the upper aerodigestive tract into the gastrointestinal tract and the airway. Alteration of its function can have a significant impact on vocal, digestive and respiratory physiology. Laryngeal cancer changes the anatomy and the patient is deprived on the vibrating source and he cannot speak. Different methods to recover phonation after total laryngectomies have been developed to produce a new voice from the 1860 to today, electrical or pneumatic types. Actually the most used technique are: the oesophageal speech, the electrolarynx and the phonatory prosthesis.
Lenses, Intraocular
Authors: Hamam Habib
Published: April 2006

The IOLs are microlenses placed inside the human eye to correct cataracts, nearsightedness, farsightedness, astigmatism, or presbyopia. There are two types of IOLs: anterior chamber lenses, which are placed in the anterior chamber of the eye between the iris and the cornea, and posterior chamber IOLs, which are placed in the posterior chamber behind the iris and rest against the capsular bag.
Linear Variable Differential Transformers
Authors: Kesavan Sunil , Reddy Narender
Published: April 2006

Linear variable differential transformers (LVDTs) are electromechanical transducers that generate an electrical output that is proportional to the displacement of their movable cores. The LVDTs offer excellent resolution and have static and dynamic characteristics that are highly suited for medical applications. This article presents the theory, fabrication, advantages, and disadvantages of these versatile transducers. In addition, the excitation, amplification and demodulation instrumentation that are used with LVDTs are discussed. The sections on selection criteria and medical applications of LVDTs could help readers develop applications for these versatile and cost‐effective transducers.
Lithotripsy
Authors: Weizer Alon Z. , Preminger Glenn M.
Published: April 2006

Shock wave lithotripsy (SWL) is a noninvasive method for the treatment of stones within the urinary tract. Since its clinical introduction over 25 years ago, SWL has revolutionized the way in which renal and ureteral stones are managed. Despite the wide array of currently available lithotripters, all rely on the same fundamentals of acoustic physics. Shock waves (i.e., high pressure sound waves) consisting of a sharp peak in positive pressure followed by a trailing negative wave are generated extracorporeally and passed through the body to fragment stones. Ultrasound or fluoroscopy are used to focus the shock wave on the stone inside the patients’ body. When the shock wave encounters the kidney stone, the force generated in the plane of the shock wave places stress on the imperfections within the stone resulting in compression‐induced tensile cracking. In addition, shock waves can cause microbubble formation on the surface of the stone. As the shock wave passes, these bubbles collapse releasing secondary shock waves or microjets impinging against the stone that result in stone destruction. While these mechanisms result in stone fragmentation, they may also be responsible for kidney injury, by primarily damaging small blood vessels within the kidney. Modifications to the design of the original lithotripter (Dornier HM3, Dornier MedTech America, Inc., Kennesaw, GA) resulted in improved patient comfort, but inferior stone fragmentation. Better understanding of the mechanisms of stone fragmentation and tissue injury caused by SWL have resulted in modifications to lithotripters that make the current machines safer and more effective.
Liver Transplantation
Authors: Gaglio Paul J.
Published: April 2006

Liver transplantation is the treatment of choice for appropriately selected patients with end‐stage liver disease. Over the last several decades, significant advances in surgical technique and immunosuppression, selection of appropriate donors, grafts, and recipients, as well as improved therapies to prevent and treat postoperative complications have greatly improved posttransplantation outcomes. Enhanced posttransplantation survival has led to the emergence of complications associated with patient longevity, including nonhepatic disease, complications of immunosuppression, infections, neoplasia, and recurrence of the primary disease for which the liver transplantation was indicated. This article will outline the history of and indications for liver transplantation, delineate short‐ and long‐term complications associated with the procedure, and discuss the role of immunosuppressive therapy, intrinsic to the long‐term success of the procedure.
Lung Sounds
Authors: Loudon Robert G. , Murphy Raymond L. H.
Published: April 2006

In this article, the medical devices and instruments that have been applied to the study of lung sounds, including the traditional acoustic stethoscope are reviewed. This survey will include sound transducers and their placement, methods, and equipment used for the recording and analysis of lung sounds, results obtained by the use of these techniques, and their clinical meaning.
Medical Education, Computers in
Authors: Hasman Arie
Published: April 2006

Computers are used in medical education in several ways. They can support life‐long learning by providing access to the literature; they can be used for simulating patients; for managing the learning process, etc. Since computers are used in medical practice students should also learn the benefits and limitations of using these information systems. These latter subjects concerns the field of medical informatics that is introduced to. Finally the possibilities of electronic patients and the use of Internet are discussed
Medical Engineering Societies and Organizations
Authors: Johnson Arthur T , Horner Patricia I
Published: April 2006

Medical engineering societies and organizations trace their roots to events early in the twentieth century, but they grew greatly in the second half. Today, opportunities in medical and biological engineering are burgeoning, and the number, as well as the interest areas, of these organizations, are expanding greatly. This article relates historical events, definitions, and contact information for many of these organizations.
Medical Records, Computers in
Authors: Srinivasan Yeshwanth , Nutter Brian
Published: April 2006

In this article, we explain the reasons for this anomaly, and we present methods to circumvent the problems associated with computer‐based medical records and to allow medical practitioners to achieve the real potential of computer‐based systems.
Microbial Detection Systems
Authors: Dolan Patricia L. , Harper Jason C. , Brozik Susan M.
Published: April 2006

Infectious diseases accounted for 25–33% of the estimated 54 million deaths worldwide in 1988, of which more than half are attributed to tuberculosis, malaria, chronic hepatitis B, diarrheal diseases, and human immunodeficiency virus/Acquired Immune Deficiency Syndrome (HIV/AIDS). Additionally, the first known cases of human influenza caused by the avian influenza virus, N5N1, were identified in Hong Kong in 1997. To address rising national and worldwide public health needs, it is desirable that a sensitive, specific, fast, and simple‐to‐operate device be employed to detect infectious agents. Microbial detection systems that attempt to meet this need have been commercially available from the late 1970s and have progressed significantly with the molecular biotechnology revolution. Contemporary microbial detection systems or biosensors typically consist of a selective biorecognition molecule connected to a transducer that converts a biochemical interaction into a measurable signal. In the near future, biomedical science can realize the integration of all laboratory equipment used in molecular biology on a chip‐based platform arrayed to detect large numbers of pathogens in a high throughput, portable device.
Monitoring in Anesthesia
Authors: Lipping Tarmo , Jäntti Ville , Yli‐Hankala Arvi
Published: April 2006

The past decade has seen an explosive increase of interest in neurophysiological monitoring during surgical anesthesia, in the Intensive Care Unit, and in the Emergency Department. A significant number of methods for the assessment of anesthetic depth have been developed. This article gives an overview of the algorithms applied in commercially available depth‐of‐anesthesia monitors and to provide some background for understanding anesthesia. In addition, several new parameters, proposed recently for the assessment of adequacy of anesthesia, are mentioned.
Monoclonal Antibodies
Authors: Laster Brenda H. , Gopas Jacob
Published: April 2006

From the time that Kohler and Milstein first published their technique of using a hybridoma to produce monoclonal antibodies (Mabs), a major and rapid progression occurred in the field of medicine, specifically immunology. Mabs began to be used as tools for diagnosing and treating disease and have proven to be valuable agents in the research laboratory. When tagged with fluorescent dyes, radioactive or heavy atoms (gold), enzymes or toxins, they help identify molecules of biological and medical importance. They can be used with microscopic techniques to identify structures or molecules within a cell. Mabs are being tested experimentally to inhibit transplant rejection, to alleviate and suppress autoimmune disease, and to detect and treat cancer. For example, Mabs can be used to remove undesirable lymphocytes from donor bone marrow cells prior to transplantation to avoid Graft versus Host disease. However, the use of Mabs produced by the mouse hybridoma can interfere with the effectiveness of the antibodies or cause allergic reactions in humans. Thus, new strategies are being explored for the construction of Mabs that can better penetrate the target tissue and are not recognized as foreign by the human immune system. Among these approaches is the cloning of human antibodies, or the placing of human antibody genes into the genome of mice that have been bred without an antibody‐producing mechanism of their own. Mabs are being used in both the diagnosis and treatment of cancer because many of the same cancer types present in different patients were shown to have similar cell surface molecules. Mabs, tagged with chemotherapeutic agents or radioactive atoms, when targeted to these tumor antigens, have the potential to destroy tumor cells. Studies are being conducted to evaluate the effectiveness of Mabs to block growth factors or receptors on tumor cells; to target specific tissue components of the tumor or its blood vessels; to interfere with cell signals; or with apoptosis (programmed cell death). When labeled with radioactive isotopes, Mabs can also be used in the diagnosis of disease in nuclear medicine procedures. They are being used in the food industry to identify either contaminating molecules, or the presence of harmful bacteria. They are also being used to create strategic reserves of vaccines and antibodies for infectious agents that could be used in biowarfare.
Neonatal Monitoring
Authors: Neuman Michael R.
Published: April 2006

This article looks more closely at electronic monitoring systems for neonatal intensive care and emphasize those aspects of these monitoring systems that differ from similar monitors for adult patients. The reader is encouraged to supplement information contained in the following paragraphs with other articles from this encyclopedia dealing with the sensors and instrumentation for similar monitoring in adults.
Nuclear Magnetic Resonance Spectroscopy
Authors: Sobol Wlad T.
Published: April 2006

This article discusses the background and theory of nuclear magnetic resonance spectroscopy as well as the equipment and experiments it employs and its applications today.
Nuclear Medicine, Computers in
Authors: Bruyant Philippe P. , King Michael A.
Published: April 2006

Nuclear medicine (NM) is a medical specialty where radioactive agents are used to obtain medical images for diagnostic purposes, and to a lesser extent treat diseases (e.g., cancer). Since imaging is where computers find their most significant application in NM, imaging will be the focus of this article.
Ocular Motility Recording and Nystagmus
Authors: Dell’Osso Louis F. , Abel L. A.
Published: April 2006

The accurate recording of eye movements for the study of ocular motor mechanisms (normal or abnormal) or for the diagnosis and treatment of ocular motor disorders requires a reliable, easy‐to‐use recording system; proper monocular calibration and linearization paradigms; and, in subjects with nystagmus or other ocular motor oscillations, knowledge of the foveation portions of the eye‐movement waveforms. In this chapter, the different types of eye movements generated by the ocular motor system, the advantages and disadvantages of commonly used recording systems, the requirements for accurate calibration of those systems, and the use of eye‐movement recordings in basic research, including clinical settings, are described.

This work was supported in part by the Office of Research and Development, Medical Research Service, Department of Veterans Affairs.
Orthopedic Devices, Materials and Design for
Authors: Bandyopadhyay Amit , Bose Susmita
Published: April 2006

Musculoskeletal disorders are recognized as among the most significant human health problems that exist today, costing society an estimated $254 billion every year, and afflicting one out of seven Americans. It is expected that the number of individuals with musculoskeletal disorders will increase over the coming years, as our population ages. Among the various options to treat musculoskeletal disorders, use of orthopedic devices is becoming a routine, where the number of annual procedures approaching five million in the United States alone. This article reviews materials and design issues of orthopedic devices. It describes how technological advancements in computer aided design and flexible manufacturing like rapid prototyping are reshaping current and future needs in orthopedic devices.
Oxygen Analyzers
Authors: McGrath Susan , Wendelken Suzanne
Published: April 2006

This article gives an overview of the analyzers used to measure gaseous oxygen in medicine, physiology, and biology. Measurement of dissolved or bound oxygen is also important in medicine and is discussed in detail elsewhere in this Encyclopedia.
Pacemakers
Authors: Murray Alan
Published: April 2006

The primary function of a cardiac pacemaker is for the treatment of bradyarrhythmias, when the heartbeat stops or responds too slowly. The clinical condition can be intermittent or permanent. If permanent, the pacemaker will control the heart continuously. If temporary, the pacemaker will respond only when necessary, avoiding competition with the heart’s own natural response. As these devices are battery powered, allowing the pacemaker to pace only when necessary conserves pacemaker energy, extending its lifetime and reducing the frequency of replacement surgery.

Over half a million new patients worldwide receive a pacemaker each year.

A pacemaker refers to all components necessary for a complete clinical pacing device. There will always be at least two components. They are the pulse generator and the lead. There may be more than one lead, such as for dual‐chamber pacing, in both the atria and the ventricle.

When pulse generators were first used in the early 1960s, they were simple devices with a battery power supply, and a circuit to produce a regular pulse rate with a defined pulse voltage and pulse‐width output. Modern pulse generators are much more complex, with sensing and output control. Special electronic circuitry has been developed, often with sophisticated microprocessor control. Battery technology has also developed significantly.

The lead has four main features. It needs a connector to connect it to the pulse generator, a long flexible wire, a biocompatible sheath over the wire, and at least one electrode to make contact with the heart.

Pacing will continue as an essential therapeutic technique, saving lives and bringing some normalit to patients with abnormal physiological heart rate control.
Transcutaneous Electrical Nerve Stimulation (TENS)
Authors: Madnani Anju , Madnani Sanjay , Cark Randall , Wells Jason
Published: April 2006

This article provides a review of pain, its definition, types, and physiology. It provides background information and theories surrounding the mechanism of analgesic action of TENS and the development of electroanalgesia. It discusses the usage, design, applications, and warnings surrounding TENS.
Peripheral Vascular Noninvasive Measurements
Authors: Schmitz Christoph H. , Graber Harry L. , Barbour Randall L.
Published: April 2006

Assessment of physiological and pathological parameters of the peripheral vasculature is important for the diagnosis and monitoring of vascular diseases, many of which can evolve into severe or even life‐threatening conditions. There is great desire for noninvasive measurement methods as alternatives or adjuncts to available invasive techniques, which often are limited in their use because of patient risk, operating complexity, or cost. The first part of the article gives a broad overview of existing noninvasive techniques for the evaluation of vascular parameters such as pressure, flow, and compliance. For each method, a general introduction is given followed by the theoretical framework of signal generation and device implementation. This is complemented by descriptions of signal analysis and clinical applications. The second part of the article briefly reviews of how available imaging‐based methods relate to the evaluation of the vasculature, including a number of advanced techniques that are presently in development or are undergoing clinical or preclinical trials.
Pharmacokinetics and Pharmacodynamics
Authors: Vicini Paolo
Published: April 2006

This article discusses the difference between pharmacokinetics and pharmacodynamics. It also reviews disease progression, population variation, and roles for modeling.
Photography, Medical
Authors: Chan Jackie K. , Fung Edward K.
Published: April 2006

Medical photography involves taking pictures for the documentation and treatment of diseases. Traditional and digital photography techniques are used in many areas of medicine for clinical and research purposes. In ophthalmology, fundus cameras take photographs of the posterior segment of the eye. The retinal images are examined for the detection of pathologies. Some camera operations, image acquisition, and enhancement techniques, as well as image analysis will be illustrated and discussed. The system of telemedicine, brought about by digital photography, bridges the gap between patients and specialized care‐givers. Photomicrography in biomedicine is the creation of images of tissues or culture samples at magnification.
Pneumotachometers
Authors: Macia Narciso F.
Published: April 2006

This article presents an overview the various types of pneumotachometers, the device used for measuring respiratory flow. It also presents their underlying principles, their strengths and weaknesses, their calibration procedures, and the methodology used to evaluate their dynamic characteristics.
Porous Materials for Biological Applications
Authors: Park Grace E. , Webster Thomas J.
Published: April 2006

Porous materials have received much attention in the scientific community because of their ability to interact with biological ions and molecules not only at their surfaces, but also throughout their bulk. Because of this intrigue, traditional applications of porous materials have involved catalysis, bioseparations, adsorption of select species, and ion exchange. As the tissue engineering field has emerged due to the continuous need for better implantable materials, porous materials have also found their niche in regenerative medicine. Specifically, porous materials have been employed as implants for various parts of the body (e.g., bone, cartilage, vasculature, central and peripheral nervous systems, bladder, and skin) either as stand‐article alone regenerative devices or as drug delivery vehicles to promote tissue growth. This article will discuss such applications of porous biomaterials focusing on events at their surfaces that can promote cell functions leading to tissue regeneration. This article will also emphasize one particularly promising research direction to improve the role of porous biomaterials in tissue engineering involving nanotechnology (or the creation of nanoscale surface features on porous materials).
Positron Emission Tomography
Authors: Kontaxakis George
Published: April 2006

Positron emission tomography (PET) is a powerful diagnostic imaging modality that depicts the biological basis of function in the organs and systems in a living body, in a unique manner that cannot be obtained by other methods. This article reviews in brief the physical principles of the technique, presents a short historical review from its first appearance until the latest developments of the technology, lists the major areas of clinical applications of PET, and refers to the current status and future prospects of the technologies related to PET, including the current PET/CT hybrid multimodality cameras and special‐purpose systems, like high‐resolution PET scanners for imaging of laboratory animals.