Biomedical Intro

8/10/2019 Biomedical Intro

1/31

BIOMEDICALINSTRUMENTATION

By: Asst.Prof. Harshul Thakur


2/31

BIOMEDICALENGINEERING

Biomedical engineering(BME) is the application of

engineering.

This field seeks to close the gap

between engineeringand medicine.

It combines the design and problem solving skills of

engineering with medical and biological sciences to

advance healthcare treatment,

including diagnosis, monitoring, and therapy.


3/31

BIOINSTRUMENTATION

Bio- of course, denotes something related with life.

Bio instrumentation implies measurement of biological

variables.

Bioinstrumentation is the use of bio-electronic instruments for

the recording or transmission of physiological information.

Biomedical Instrumentation involves devices designed and

connected together in a scientifically appropriate manner to

sense (or capture) signals (e.g: electromagnetic, mechanical,

thermal, acoustic) and process them for human display and/orfurther processing for control, therapy etc. like Digital

Thermometer senses the temp. using electronic sensor then

filter, amplify and convert into analog quantity and display.


4/31

KEYROLLS

BioMedical Engineer A person working in research or development in the

interface area of medicine and engineering.

(Develop instruments and measurement devices)

Clinical Engineer

A practitioner working with physicians and patient.

( Proper use of instruments during patient care)

Bio Medical Equipment Technician(BMET) A person having knowledge about the theory of

operation and biomedical equipments.

(Capabilities like installation, calibration andmaintenance..)


5/31

MAJORPROBLEM

Communication gap between engineers and

medical professionals.

Development and use of biomedical instruments

must be a joint effort of engineers or technicians

and the physician or nurse, every effort must

consider to avoid or overcome this

Communication.


6/31

BIOMETRICS

The branch of science that includes the measurement

of physiological variables and parameters is known as

biometrics. Bio medical instrumentation provides the

tools by which these measurements can be achieved.

In the design and specification of medical

instrumentation system, each of the following factors

should be considered:

Range, Sensitivity, Linearity, Hysteresis, Frequency

Response, Accuracy, S/N ratio, Stability, Isolation and

Simplicity.


7/31

RANGE

The range of an instrument is generally considered to

include all the levels of input amplitude & frequency

over which the device is expected to operate.

The objective is to provide an instrument that will give

a usable reading from the smallest expected value

of the variable or parameter being measured to the

largest.


8/31

SENSITIVITY

The sensitivity of an instrument determines how

small a variation of a variable or parameter can be

really reliably measured.


9/31

LINEARITY

The degree to which variations in the output of an

instrument follow input variations is referred to as

the linearity of the device.


10/31

HYSTERESIS

It is a characteristic of some instruments where by

a given value of the measured variable results in a

different reading when reached in an ascending

direction from that obtained when it is reached in a

descending direction .

(Mechanical friction in a meter)


11/31

FREQUENCYRESPONSE

The frequency response of an instrument in its

variation in sensitivity over the frequency range of

the measurement. It is important to display a wave

shape that is a faithful reproduction of the original

physiological signal.

An instrument system should be able to respond

rapidly enough to reproduce all frequency

components of the waveform with equal sensitivity.


12/31

ACCURACY

1. Accuracy

Closeness to the true value of measurand.


13/31

ACCURACY

It is a measure of systemic error. Errors can occur in a multitude ofways. Although not always present simultaneously, the followingerrors should be considered.

1. Errors due to tolerances of electronic components.2. Mechanical errors in meter movements.3. Component errors due to drift or temperature variations.4. Errors due to poor frequency response.5. Errors due to change in atmospheric pressure or temperature.6. Reading errors due to parallel inadequate illuminations or

excessively wide ink traces on a pen recording.

Two additional sources of Errors are

Correct instrument zeroing or making correct baseline. The effect of the instrument on the parameter to be measured &

vice versa. ( Specially in measurements in living organism )


14/31

SIGNALTONOISERATIO

It is important that the signal to noise ratio be high

as possible.(Noise due to hospital environment, inferencedue electromagnetic, electrostatic or may be due to poor

grounding )

STABILITY

In control engineering, Stability is the ability of a

system to resume a steady state conditionsfollowing a disturbance at the input rather than be

driven into uncontrollable oscillation.


15/31

ISOLATION

Instrument does not produce a direct electrical

contact between subject and ground.

Electrical Isolation is to be made for avoidinginterference between different instruments used

simultaneously. It can be achieved by using

magnetic or optional coupling technique or using

radio telemetry.

Telemetry is also used where movement of the

person or animal to be measured.


16/31

SIMPLICITY

All systems & instruments should be as simple as

possible to eliminate the chance of component or

human error.


17/31

PRECISION

A measure of the degree of agreement within a groupof measurements repeatability of a system-(however no guarantee of accuracy)

Results have Low scatter excellent precision


18/31

ADDITIONALFACTORSTHATADDDIFFICULTYOF

OBTAININGVALIDMEASUREMENT

1. Safety Considerations.

2.The environment of the hospital in which these

measurements are performed.

3. The medical person usually involved inmeasurements.


19/31

THEBASICOBJECTIVESOFANYINSTRUMENTATION

SYSTEMGENERALLYFALLINTOONEOFTHE

FOLLOWINGCATEGORIES:

Information Gathering System. To measure natural phenomena.

Diagnosis System. Measurements are made to detect and correction of some

malfunction of the system. Classified as Troubleshooting

equipment. Evaluation System.

To determine the ability of a system to meet its functionalrequirements. These could classified as proof ofperformance and quality control tests.

Monitoring System.

To monitor some process or operation, to obtain continuousinformation about the state.

Control System. Automatically control of operation of a system based on

changes in one or more of the internal parameters or in theoutput of the system.


20/31

BIOMEDICALINSTRUMENTATIONCANGENERALLY

BECLASSIFIEDINTOTWOMAJORTYPES:

1. Clinical Instrumentation .

2.Research Instrumentation.


21/31

CLINICALINSTRUMENTATION

Basically devoted to the area of

Diagnosis

Patient care

Treatment of Patients ( Therapeutic use )


22/31

RESEARCHINSTRUMENTATION

It is used primarily in the search for new knowledge

related to various systems that compose the human

organism.

Some instruments can be used in both areas.


23/31

MEASUREMENTS

Biomedical instrumental measurements aredivided in to two categories.1.In Vivo2.In Vitro

1. IN VIVO MEASURMENTS In vivo measurementsare made on or within the living organism itself.

e.g. A device inserted into the blood stream tomeasure the PH of the blood directly.

2. IN VITRO MEASURMENTS In vitro

measurements are made outside the body , eventhough it relates to the functions of the body. e.g. Measurements of PH of sample of blood,

that has been drawn from patients body.

MAN INSTRUMENTATION SYSTEM


24/31

24

MANINSTRUMENTATIONSYSTEM

A Measuring systemis required to compare a quantity with astandard or to provide an output that can be related to the quantitybeing measured.

Components of the Man Instrument System

Subject: The human being or whom measurements are made.

Stimulus: That evokes a specific functional reaction in an organ.

Display

Recorder

Signal

conditioner

Measurand

Sensor

Input Output

DEFINITIONS


25/31

DEFINITIONS

Sensor:is a device that detects a change in a physical stimulusand turns it into a signal which can be measured orrecorded

A Transducer is a device that transfers power from one system to

another in the same or in a different form.

Signal conditioning:Amplifying, wave shaping, filtering, rectifying,

Display Equipment : The electrical output of a signal

conditioning equipment must be converted in to form thatcan understand and perceived easily.

Recorder: To store the measured information andprocess it any time.

WHY DO WE NEED INSTUMENTATION IN MEDICAL


26/31

WHY DO WE NEED INSTUMENTATION IN MEDICAL

FIELD

Diagnosis and therapy depend heavily on the use of medical

instrumentation. Like

ENG(electronystagmography),ECG(electrocardiography),EMG

(electromyography),ERG(electroratinography

EEG(electroencephalography),MEG(magnetoencephalography

), MRI(magnetic resonance imaging),Analysis of data, its storage and Transmission can be done

Collection of data qualitative and/or quantitative

Intelligent control is possible

Decision making and Treatment planning based on the

decision

Wide Operating range and Applications are flexible


27/31

PHYSIOLOGICALSYSTEMSOFTHEBODY

To obtain the valid measurements from a living

human being, it is necessary to have some

understanding of the subject on which the

measurements are being made.

With in the human body can found different types of

signals each of which communicates with the

external environment and internally with the other

systems of the body.

T


28/31

TYPESOFSIGNALSTOBEMEASUREDBYBIOMEDICAL

INSTRUMENTS

Biomedical signal are those which convey information

regarding Human body and biomedical instruments detectsand measure those signals. Types of signals are as follows

Bio-Electric signals :- generated by the cell membrane

potential .

Bio- Acoustic Signals :- e.g. blood flow in heart, air flow inlungs generate acoustic signals

Bio-Mechanical signals :- it includes all types of motion,

movement, pressure and flow signals. e.g. chest walls

movement during breathing


29/31

CONTD.

Bio- Chemical Signals:- generates from the chemical analysis

e.g.CO2and O2 pressure. Bio-Magnetic Signals:- very weak signals from heart, brain,

lungs measured by Magneto-encephalograph.

Bio-Optical Signals:- Blood oxygenation is obtained by

measuring the light scattering from tissue at differentwavelength

Bio-Impedance Signal:- injecting current in a tissue and

measuring the voltage drop gives us skin resistance, blood

vol., blood distribution etc.


30/31

SOURCE OF BIOMEDICAL SIGNALS


31/31

Date post:	02-Jun-2018
Category:	Documents
Upload:	jaswanth-nani
View:	221 times
Download:	0 times

Biomedical Intro

Documents