42043 - Biomedical Instrumentation BS

Learning outcomes

The course aims at furnishing the basic knowledge for the design, realization and use of instrumentation devoted to clinical diagnosis and therapy. Concomitantly, the lessons will tackle problems of analysis and application of electronic circuits to biomedical instrumentation.

Course contents

1. Electronic circuits, amplifiers and filters for biomedical instruments - Operational amplifiers: inverting, non-inverting, differential and buffer configuration; common mode rejection ratio (CMRR); input and output impedances; integrator; differentiator; charge amplifier. Instrumentation amplifier: differential gain; CMRR; common mode and differential input impedance. Isolation amplifier: galvanic and optic isolation. Analogic filters: low-pass, band-pass, high-pass (transfer function and Bode diagrams). Voltage comparators. Signal modulation and demodulation. Analog-to-digital and digital-to-analog conversion.

2. Measurement of electroencephalographic potentials - The ultrastructure of the cerebral cortex  e the origin of surface EEG. The rhythms of the brain: normal EEG waves; the abnormal EEG (epilepsy); sleep patterns. Electrodes for EEG and the international 10-20 system electrode placement. Multichannel EEG recording systems: block diagram of the analogical and digital systems; system specifications; design of the conditioning block (amplifier and filters). The evoked potentials.

3. Ultrasound systems for clinical diagnosis - Ultrasound generation (piezoelectric materials). Propagation of ultrasounds in tissues. Echography: functioning principles, resolution, scan modes. Echotomography. Pulse-echo applications: echocardiography; ophtalmology; echoencephalography. Transit-time flowmeters: functioning principles; block scheme; circuits. Phase-shift flowmeters: functioning principles and block scheme. Doppler flowmeters: functioning principles and block scheme. Continuous-wave non-directional Doppler flowmeter. Continuous-wave directional Doppler flowmeter. Pulsed-wave Doppler flowmeters.

4. Plethysmography for measurements of blood volumes and flows - Plethysmography: definition and techniques. Displacement plethysmography (air-displacement, water-displacement, strain-gauge, capacitance). Venous occlusion plethysmography. Photo-plethysmography: light emitting diodes; phototransistors; circuit. Impedance plethysmography: impedance of the tissues; functioning principles; bipolar and tetrapolar circuits; self-balancing method. Impedance cardiography.

5. Measurements of the respiratory system - Gas laws; pulmonary volumes and capacities. Spirometer: system description; functioning principles; test with spirometer for measuring the functional residual capacity. Total-body plethysmography: system description and functioning. Inductance plethysmography. Impedance pneumography. Respiratory flow measurement: turbine flowmeters; ultrasound flowmeters; hot-wire anemometers; pneumotachometers. Measurement of gas concentration: mass spectroscopy; infrared spectroscopy; paramagnetic oxygen sensors.

6. Clinical laboratory instrumentation - Electrochemical sensors. Chemical fibrosensors. Blood analyses: colorimeter; flame photometer; spectrophotometer; fluorometer; autoanalyzer; blood cell counter.

7. Defibrillators and cardioverters – Definition and clinical use. Defibrillator: block scheme and specifications. Defibrillator circuits: RLC defibrillator (damped sine wave); dual-peak defibrillator; trapezoidal-wave defibrillator. Block scheme of a cardioverter. Electrodes for defibrillators. Routine maintenance. Internal defibrillators

8. Pacemakers – Definition, clinical use, classification. Asynchronous pacemaker. Demand-type synchronous pacemaker. Atrial synchronous pacemaker. Rate-responsive pacemaker. Power supply; impulse generator; electrodes and cables.

9. Anaesthesia equipment and ventilators - Anaesthesia machine. Positive-pressure ventilators: block scheme; ventilation modes. Anaesthesia ventilators. Intensive care ventilators.

10. Engineering principles of medical imaging systems - X-ray machines: nature and generation of x-rays; block scheme of a x-ray machine; design of a x-ray tube. Computed tomography. Nuclear medicine systems. Single Photon Emission Computed Tomography (SPECT). Positron Emission Tomography (PET).

Readings/Bibliography

Lecture notes provided by the teacher.

Suggested books:

•  G. Avanzolini, Strumentazione biomedica: progetto e impiego dei sistemi di misura, Patron Editore, Bologna, 1998, 2th edition.
• J.G. Webster, Medical Instrumentation: Application and Design, Wiley and Sons, NY, 1998, 3th edition.
• W. Welkowitz, S. Deutsch, Biomedical Instruments: Teory and Design, Academic Press, NY, 1992, 2th edition.
• J.J. Carr, J.M. Brown, Introduction to Biomedical Equipment Technology, Wiley &Sons, NY, 4th Edition, 2000.

Teaching methods

The course mainly consists of lessons in classroom. The classes aim to furnish the theoretical knowledge on functioning principles and design elements of biomedical instrumentation. The theoretical concepts will be accompanied by exempla and exercises on analysis and design of biomedical systems. Laboratory practice will be performed at the Biomedical Engineering Laboratory.

Assessment methods

Examination consists of an oral test. To be admitted at the oral test, the student has to pass a preliminary written test. The tests aim to evaluate the theoretical knowledge of the student and his/her abilities in facing design problems. Moreover, the analysis and synthesis capacities, correctness of language, clearness of concepts and exposition will be evaluated too.

Teaching tools

Blackboard, notebook, projector, lecture notes, biomedical engineering laboratory

Office hours

See the website of Elisa Magosso