Biomedical Instruments


#1

“Biomedical instruments” refer to a very broad class of devices and systems. A biomedical instrument is an ECG machine to many people. To others, it’s a chemical biosensor, and to some it’s a medical imaging system. Current estimates place the worldwide market for biomedical instruments at over $200 billion.

Biomedical instruments are ubiquitous; they are significant to the broader technology and biotechnology sectors; and, finally, they are vital to many medical and scientific fields.

Even though there is a wide variety of instruments, almost all of them can be modeled using the simple diagram below.

Biomedical%20Instruments

All biomedical instruments must interface with biological materials (by definition). The interface can by direct contact or by indirect contact (e.g., induced fields).

1. Basic Sensors and Principles – including biopotential electrodes

2. Electronic Interfacing: including system noise figure, system bandwidth, pre-amplifiers, postamps, instrumentation amps, A/D and D/A converters, aliasing, triggering and signal averaging

3. Computation: including data capture and signal processing

4. Systems: complete system response using specific examples (electromyogram, pressure sensors and blood pressure measurements, flow sensors and blood flow measurements, and chemical biosensors)

Detailed Explanation -

Sensors and Actuators

A sensor must:

• detect biochemical, bioelectrical, or biophysical parameters
• reproduce the physiologic time response of these parameters
• provide a safe interface with biological materials

An actuator must:

• deliver external agents via direct or indirect contact
• control biochemical, bioelectrical, or biophysical parameters
• provide a safe interface with biologic materials

Electronics Interface

The electronics interface must:

• match the electrical characteristics of the sensor/actuator with the computation unit
• preserve signal-to-noise ratio (SNR) of sensor
• preserve efficiency of actuator
• preserve bandwidth (i.e., time response) of sensor/actuator
• provide a safe interface with the sensor/actuator
• provide a safe interface with the computation unit
• provide secondary signal processing functions for the system

Computation Unit

The computation unit must:

• provide primary user interface
• provide primary control for the overall system
• provide data storage for the system
• provide primary signal processing functions for the system
• maintain safe operation of the overall system