BIOMEDICAL ENGINEERING

Transcription

1 index INTRODUCTION BIOMEDICAL INSTRUMENTATION SCOPE OF THE LABORATORY: OBJECTIVES PROFILE OF THE COURSE MANUALS AND SOFTWARE POWER SUPPLIES BASE FRAME WITH POWER SUPPLY, INTERFACE TO PC AND VIRTUAL INSTRUMENTATION BASE FRAME WITH POWER SUPPLY AND INTERFACE TO PC DL 3155AL2RM DL 3155AL2 CAI SOFTWARE LABORATORY MANAGEMENT SOFTWARE TRANSDUCERS AMPLIFIERS FILTERS PULSE CONVERSION ECG EEG - EMG PULSE RATE TEMPERATURE AND RESPIRATION GALVANIC SKIN RESISTANCE AUDIOMETER T.E.N.S. MAGNETOTHERAPY ELECTROSTIMULATION LASER THERAPY IONOPHORESIS ULTRASOUND THERAPY BLOOD PRESSURE MONITORING SOFTWARE MODULES DL NAV DL LAB DL 3155BIO1 DL 3155BIO2 DL 3155BIO3 DL 3155BIO4 DL 3155BIO5 DL 3155BIO6 DL 3155BIO7 DL 3155BIO8 DL 3155BIO9 DL 3155BIO10 DL 3155BIO11 DL 3155BIO12 DL 3155BIO13 DL 3155BIO14 DL 3155BIO15 DL 3155BIO16

2 INTRODUCTION The prosperity of a nation is directly proportional to the skills and the education level of its people. In that perspective, De Lorenzo is able to provide a significant contribution in the development and modernization of education and research institutions and to ensure that all client needs are thoroughly analysed by our project development team. Established in 1951, De Lorenzo is the oldest Italian leading manufacturer of educational equipment. Nowadays, with a huge number of products and laboratories installed world-wide, De Lorenzo is continuing its tradition of being fully devoted to solve teaching and learning problems for its customers in technical universities, polytechnics, technical and vocational schools, education centres, teacher training centres, etc. in all of the above areas. With this catalogue, De Lorenzo wants to introduce a new laboratory that has been conceived for the specific purpose of training biomedical engineers and biomedical laboratory technicians. Biomedical Engineering is a new sector of Science and Technology and the objective of the laboratory is to create engineers that are able to operate in the biomedical industrial field, for the design and manufacturing of biomedical equipment, or in the public and private structures, for the maintenance and repair of the same type of products. Once again, here, in De Lorenzo, we are ready to help in developing new knowledge, skills and technologies and to meet the demands for a continuously changing industrial environment. Biomedical INSTRUMENTATION The biomedical engineering forms a new discipline, born from the close co-operation between engineering and medical-biological sciences. A definition of bioengineering, among the many possible and equivalent, is the following: the bioengineering is the discipline that uses the methodologies and the technologies that are typical of the engineering in order to understand, determine and try to solve medical-biological problems, through a close co-operation of the experts of the different sectors, that is, engineers and doctorsbiologists. The main objective of the biomedical engineering is the development of the necessary instrumentation in different application fields of the medical practice, such as diagnosis, therapy and rehabilitation.

3 SCOPE OF THE LABORATORY: OBJECTIVES Within the more general environment of the electronic instrumentation, the biomedical instrumentation is characterized by some peculiar elements, that are correlated to the particular field of application, due to the fact that it has to be interfaced to the human body. This laboratory deals with the design and operating principles of the most common biomedical instrumentation in the field of diagnosis, therapy and rehabilitation. The objective is that of studying in detail different circuits that are commonly used in the clinic practice by means of four propaedeutic modules (DL 3155BIO1 through DL 3155BIO4) and twelve application modules (DL 3155BIO5 through DL 3155BIO16). Each module is complete with both a theoretical manual and an operating manual. In the theoretical manual there are the medical-biological bases of the specific application as well as the operating principles and the circuit aspects of the electronic instrument. The operating manual describes a series of exercises that allow both the in depth study of the theory and the hands-on evaluation of the performances of the instrument. Furthermore, a special attention is paid to the problems related to the electrical safety of the patient. PROFILE OF THE COURSE This laboratory has been designed to train in particular two types of professionals: Biomedical engineers, that take care of the design and of the development of the equipment. Biomedical laboratory technicians, that deal with the operation and the maintenance of the equipment. The course is targeted to provide the following competences: basic knowledge of biological systems and signals; knowledge of the measurement methodologies related to biomedical signals; study of the circuit solutions that are used in the biomedical instruments; acquisition of circuit diagnosis methods for the detection of possible faults and malfunctions. MANUALS AND SOFTWARE Each module is provided with a Theoretical Guide and a Practical Guide, strictly interconnected, to allow students a simple and gradual learning and teachers an efficient tool for planning and performing their courses. The Theoretical Guide is divided in Lessons while the Practical Guide contains several exercises with step-by-step procedures and tests for the students. On request, the modules can be supplied together with a CAI software that allows students performing their learning activities through a Personal Computer, without the need for any other on-line documentation. Moreover, the classroom can be provided with a Laboratory Management software, to allow the realization of fully integrated training systems, where all the educational tasks are managed and controlled by the Teacher, from his own work station.

4 POWER SUPPLIES BASE FRAME WITH POWER SUPPLY AND INTERFACE TO PC AND VIRTUAL INSTRUMENTATION DL 3155AL2RM Power supplies: 0/+15 Vdc, 1 A 0/-15 Vdc, 1 A +15 Vdc, 1 A -15 Vdc, 1 A +5 Vdc, 1 A -5 Vdc, 1 A Vac, 1 A Virtual instrumentation: Multimeter 3 and 3/4 digits dc/ac voltage: 400 mv, 4 V, 40 V, 400 V or Autorange resistance: 400 Ohm, 4 kohm, 40 kohm, 400 kohm, 40 MOhm dc/ac current: 200 ma, 8 A Function Generator sinusoidal, square, triangular, dc frequency: 0.1 Hz khz output: ± 10 V attenuator: 0 db, -10 db, -20 db Digital oscilloscope dual trace oscilloscope input: dc/ac, 1 MOhm meas. ranges: 20/50/100/200/500 mv, 1/2/5 V per division sampling frequency: 100 Hz to 10 MHz Digital Pattern Generator output rate: from 200ms to 10s pattern selection: manual or automatic display: 20 states of the patterns Logic Wave Analyzer display: 20 states of the inputs Features: Interface board for connection to PC. Robust structure and modern design. Voltage regulation and protection against over voltage or short circuit. Complete with a set of connecting cables. BASE FRAME WITH POWER SUPPLY AND INTERFACE TO PC Power supplies: 0/+15 Vdc, 1 A 0/-15 Vdc, 1 A +15 Vdc, 1 A -15 Vdc, 1 A +5 Vdc, 1 A -5 Vdc, 1 A Vac, 1 A Features: Interface board for connection to PC. Robust structure and modern design. Voltage regulation and protection against over voltage or short circuit. Complete with a set of connecting cables. DL 3155AL2

5 SOFTWARE CAI SOFTWARE DL NAV Each board of the system can be supplied complete with a Student Navigator software that allows students to perform their learning activities through a Personal Computer, without the need for any other documentation. Moreover, the Student Navigator is provided with an interface to the Laboratory Management software DL Lab, to allow the realization of fully integrated training systems, where all the educational tasks are managed and controlled by the Teacher, through his own work station. Features: theoretical subjects through PC with hyper textual navigation according to the standard World Wide Web Internet method practical training guided through PC, with test questions and computer control of the answers fault insertion from PC (or from remote teacher station) and troubleshooting operations with computer control of the answers use of the computer as a standalone work station or integrated in the computer network of the laboratory LABORATORY MANAGEMENT SOFTWARE DL LAB This application allows Teachers a complete management of all the activities inside the Laboratory: assignment of the lessons that the students must study monitoring of the activities of each student (in/out from the lessons, right or wrong answers, rating, etc.) direct communication with each student workstation (sending and receiving messages, fault insertion on the student workstations recording of all the students activities in a database (Microsoft Access compatible) on the Teacher s workstation processing of the stored data for the control of the individual or group learning level The DL LAB software offers a simple and effective user interface (similar to Explorer in Windows) that allows teacher to move among students, lessons, faults and results in the same way he is used to explore the computer resources. Features: unlimited number of classes (one database for each class) unlimited number of students per class maximum number of work stations connected at the same time: bit operating systems user interface similar to Windows Explorer control of the Students access through Username and Password assignment of the lessons to study, insertion of the faults, ac- cess control communication with the students and message exchange visualization of every activity performed by the students complete list of all the on-line lessons and faults results of each student in the last performed lesson: details relevant to each question, average rating, time results of class performance export of the results in ASCII format

6 THE MODULES TRANSDUCERS DL 3155BIO1 This block deals with biomedical sensors and transducers. The classification criterion that has been used in this course for the sensors and the transducers is based on their physical operation principle. Resistive, optical or photoelectrical sensors and transducers, used in the temperature data and optical signals acquisition, are studied in this board. The bio-engineering and the biomedical instrumentation Biomedical signals Measurement systems of biomedical signals Characteristics of the transducers The temperature sensors The optical and opto-electronic sensors Temperature sensors C/ F converter U/f transducer Photodiode Phototransistor Optocoupler AMPLIFIERS DL 3155BIO2 The electrical signal, generated by sensors, is usually at a low level of amplitude and power, so that it is necessary to amplify it before its transfer, further analogue or digital processing and visualization. In this course we will study the characteristics of the pre-amplifiers and amplifiers for the processing of biomedical signals. Inverting and non inverting configuration of an OP. AMP. at low and high voltage gain Differential Amplifier: differential gain and frequency function Study of the input and output impedances Pre-amplifiers Differential amplifier for the instrumentation Amplification of biomedical signals The ideal operational amplifiers The real operational amplifiers Preamplifier and main amplifier Evaluation of the CMRR

7 FILTERS DL 3155BIO3 In this course we will study the devices that allow the passage of biomedical signals with given characteristics, while attenuating those that do not comply with the required parameters. This board does not substitute the medical device under study. The results of the experiments have no medical value. They are just for Filtering of the biomedical signals Types and characteristics of the filters Main configurations of the 1st and 2nd order filters Active LP, HP and KHN filters Filters applications in the biomedical instrumentation Notch filter Filters used in the measurement of the EEG and of the EMG Low-Pass Band-Pass High-Pass Notch Band-Stop PULSE CONVERSION DL 3155BIO4 The events monitoring systems such as the frequency of the cardiac pulsations, the breathing frequency, etc., require that an analogue signal be converted to pulses and visualized on a display in order to be measured. In this course students will study some circuits for analogue to pulse conversion, sound indicator and analogue frequency meter. This board does not substitute the medical device under study. The results of the experiments have no medical value. They are just for Role of the analogue-pulsed conversion Different types of pulse generators Description of a conversion block Role of the audio and visual signaling Description of a visual signalling block Description of an audio signaling block Different types of visual and audio indicators Role of the measurement of the frequency Instruments for the measurement of the frequency for biomedical applications Difference between analogue and digital meters Circuit for the conversion of an analogue signal to a pulse signal Measurement of the frequency of a periodical signal Evaluation of the average cardiac frequency

8 ECG EEG - EMG DL 3155BIO5 The bio-electrical potentials are currently recorded as a routine in several specialities of the modern clinical practice. Such potentials are the result of an electrochemical activity of a class of cells, named excitable cells, that form the nervous, muscular and glandular tissues. The measurement of the bioelectrical phenomena is, therefore, used to learn the electrochemical activity of such tissues. The most widely used bioelectrical signals, such as the electrocardiogram, the electroencephalogram and the electromiogram, have a very low amplitude and are generated by sources that have a high internal impedance. In this course we will study first of all the general specifications of the systems for the measurement of bioelectrical signals and subsequently the characteristics of some special systems. This course comprises a further instrument, the ECG SIMULATOR, which is mandatory to provide power supply to the circuit and provides a simulated ECG signal for performing experimental activity. The bio-potentials and their measurement The heart and the measurement of its electrical activity The muscles and the measurement of their electrical activity The brain and the measurement of its electrical activity Electrocardiograph: to record the potentials that are generated on the surface of the body during the process of stimulating the cardiac musculature Electroencephalograph: to record the cerebral electrical activity Electromiograph: to record the electrical activity of the muscles and of the relevant nervous fibres ECG SIMULATOR This is an external block which is provided together with DL 3155BIO5. ECG-SIMULATOR provides the power supply to the ECG-EEG-EMG panel in order to meet the requirements for patient safety. Moreover a simulated ECG signal is generated with amplitude of 4 mv pp. ECG signals are available with two frequency rates, such as 60 or 120 bpm (beats per minute). ECG- SIMULATOR is mandatory when an actual ECG measurement is performed on a patient. In fact the external block provides a multiple switching which permits to select the correct LEAD when electrodes are placed on the patient. A calibration fixed level of 1 mv can be selected to perform ECG calibration.

9 PULSE RATE DL 3155BIO6 At every heartbeat the arterial blood pressure raises (systolic period) and the dimension of the tips of the fingers slightly increases, while the higher oxygenation causes the decrease of the optical density of the skin tissue. During the cardiac relaxation period (diastolic period) the pressure decreases, the density increases and the physical dimension of the tips of the fingers decreases. Since these cyclical variations follow the cardiac rhythm, they can be used to measure the frequency of the peripheral pulsations. Concept of cardiac rhythm and typical values, in different subjects and in different conditions of the subject Measurement of the cardiac frequency The use of optical sensors Comparator with hysteresis for the processing of the signal provided by the optical sensor PLL, frequency dividers, PIC and their role in the measurement and visualization of the cardiac rhythm Recordings of the peripheral pulsations in a finger Effects of breathing and exercising on the frequency of the pulsations Effects of the temperature on the measurement of the frequency of the pulsations TEMPERATURE AND RESPIRATION DL 3155BIO7 The temperature of the body is mainly regulated by the hypothalamus. This region of the brain regulates the homeostatic mechanism that promotes both the production and the loss of heat. In spite of the changes in the environmental conditions, the hypothalamus keeps constant the internal temperature. Moreover, the external temperature of the skin is controlled by both the hypothalamus and the thermal sensors that cause both the afflux of blood to the skin and the perspiration. The breathing system transfers the oxygen to the blood and expels the carbon dioxide in the atmosphere. The breathing frequency can be calculated by measuring the expansion or the contraction of the chest and also by measuring the movement of air that enters and exits from one nostril. Anatomy of the respiratory airways or tracts Measurement of the body temperature Temperature sensors Temperature meter Measurement of the respiratory frequency Variation of the temperatures on the surface of the body Advantages of the use of the electronic instrumentation with respect to the classic mercury thermometers for the measurement of the temperature Main functions of the breathing system Breathing frequency while relaxing and while exercising

10 GALVANIC SKIN RESISTANCE DL 3155BIO8 At the passage of an electrical current, the skin shows a resistance that is normally within the 100 kohm to 1 MOhm range. Such resistance decreases during periods of emotional stress. The changes of the resistance are particularly significant on the palm of the hands and on the plant of the feet. Moreover, the surface of the skin shows an electrical potential, that can reach up to 50mV and that can equally be influenced by emotional states. This board does not substitute the medical device under study. The results of the experiments have no medical value. They are just for Galvanic resistance of the skin The function of the different skin layers The electric characteristic of the skin Behaviour of the human body at the passage of an electric current Different types of measurements Measurement of the resistance and of the potential Visual and audio signaling Variation of the resistance in direct current of the skin with relation to humidity Recording of the changes of the galvanic resistance of the skin due to emotional or physical stimuli Typical circuit that is used in the monitoring of the GSR AUDIOMETER DL 3155BIO9 The audiometer is used in the medical field to measure the threshold of hearing sounds. An audio signal generator generates all the frequencies between 20 Hz and 25 khz. The patient, through a headset, checks the level of sensitivity in his ears. Biophysics of sounds Physiology of the auditory system: perception, transmission and conduction of the sound Diagnosis and evaluation of the acoustic deficit Audiometer Typical circuit of an audiometer Graphical visualization of the hearing sensitivity of a patient in the whole frequency range

11 T.E.N.S. DL 3155BIO10 T.E.N.S., or Transcutaneous Electrical Nerves Stimulation, is a particular low frequency wave form that, once applied through electrodes in the area of the cutaneous projection of the pain (triggers area), allows an almost immediate and longlasting reduction of the painful sensibility. For this reason it is an effective, safe and innocuous therapy for the treatment of all the muscle and skeleton pains, neuralgias, rheumatic pains, articular pains, headaches, lumbar pains, sciatic pains and other affections. T.E.N.S. technology Physical principles The importance of the frequency of the pulses Gate control theory Theory of releasing the endorphins Applications for T.E.N.S. Mechanism through which electrical pulses are able to perform an analgesic effect Typical circuit that is used in the transcutaneous electrical nervous stimulation results of the experiments have no medical value. They are just for MAGNETOTHERAPY DL 3155BIO11 Low frequency and low intensity magnetic fields and high frequency electromagnetic fields, where the magnetic component is almost equal to the electrical component, act on the whole body through an effect of substitution or activation of the missing electrical currents. Consequently, they cause a fast regeneration of the bony and cutaneous tissues and considerably increase the immune defenses of the body. Outline of electromagnetism The electromagnetism in the medical practice The magnetotherapy Equipment for magnetotherapy Main functions of the magneto therapy Typical circuit of a magneto therapy results of the experiments have no medical value. They are just for

12 ELECTROSTIMULATION DL 3155BIO12 The electro stimulation, or the involuntary muscular contraction that is caused by electrical pulses, is a practice used both in rehabilitation and in sport or fitness. It causes selective muscular contractions, more powerful and extended than those that are possible through voluntary efforts; it allows, without physical efforts, amazing results such as the increase of the tone and of the volume of the muscles; it increases the metabolism of the fats with consequent reduction of the adipose zones; it tones up the muscles and it progressively reactivates the functionalities of limbs that need re-education. Biomedical techniques for the electrostimulation The electrostimulation for passive gymnastics The electrostimulator Main therapeutical effects in sport and beauty fields Typical circuit that is used in electro stimulation LASER THERAPY I.R. is a beam of non visible, unidirectional and monochromatic light (since it is emitted in the infrared band) that transfers remarkable amounts of energy represented by photons. This radiation does not produce heat, it does not alter the tissues and it is not felt by the patient that is under therapy. It performs an anti-inflammatory and revitalizing action. Introduction to the Laser Features of the Laser Nd:YAG Laser CO2 Laser Semiconductor Laser Main applications of the laser therapy Typical circuit of an IR laser DL 3155BIO13

13 IONOPHORESIS DL 3155BIO14 The ionophoresis is a technique that allows the substances in ionic form to penetrate from the surface of the skin to the deeper layers through a current. These substances, named active principles, of different dimensions and molecular weights, become extremely effective because they act inside the skin tissues at higher concentrations. Leduc experiment Physical-chemical bases Therapeutic effects Application methods Main therapeutic effects Typical circuit that is used in the ionophoresis ULTRASOUND THERAPY DL 3155BIO15 The penetration power of ultrasounds in the tissues of the human body has revolutionized the field of medical diagnostics. This property is successfully used also in physiotherapy, where ultrasounds have demonstrated a remarkable curative validity in several affections, such as arthritis, lumbagos, articular stiffness and many others. Ultrasound Medical applications of ultrasound Method of application Oscillators Power supply switching Main applications of the ultrasound therapy Typical circuit used in ultrasound therapy

14 BLOOD PRESSURE MONITORING DL 3155BIO16 In blood vessels there must be a certain pressure in order that the blood can properly flow. Each heart beat causes a pressure wave that is transferred to the arteries. The upper value (systole) is the maximum pressure that is recorded in the artery in consequence of the heart beat. The lower value (diastole) corresponds to the pressure that we have in the arteries between two heart beats. Therefore, it is necessary to properly evaluate the pressure and its variability through a pressure and heart beat digital meter. The blood pressure Hypertension Measuring the blood pressure The sensors Measurement of the blood pressure and heart beat Evaluation of the average cardiac rate Typical circuit used in blood pressure monitoring