302lect_diagtherapinstr

8/12/2019 302Lect_DiagTherapInstr

1/44

e ca nstrumentat on

11/19/2010


2/44

Medical instrumentation

Definition: instrument for sensing, diagnostics,

therapeutics or surgery of human being.

2


3/44

Medical instrumentation

Definition: instrument for sensing, diagnostics,

therapeutics or surgery of human being. Fundamental purpose: to enhance the capabilities

of human beings to help themselves and each

o er.

3


4/44

Medical instrumentation classification

Diagnostic instrumentation

Therapeutic instrumentation Clinical laboratory instrumentation

4


5/44

Medical instrumentation classification

Diagnostic instrumentation

Therapeutic instrumentation Clinical laboratory instrumentation

Diagnosis Therapy

5


6/44

Dia nostic instrumentation

Definition: a device that gathers information

leading to the identification of a disease or

disorder.

Stethoscope

(invented in 1819)

CT

(X-ray computed tomography )

6


7/44

Dia nostic instrumentation

Definition: a device that gathers information

leading to the identification of a disease or

disorder.

Stethoscope

(invented in 1819)

CT

(X-ray computed tomography )

7


8/44

Generalized com osition of

diagnostic instrument

Measurand Sensor Signal

processing

Outputdisplay

8


9/44




processing

Outputdisplay

Measurand: physical quantity, property, or

condition that the system measures.

9


10/44

Measurand

Examples:

Blood oxygen saturation Electrical activity of the heart

Tumor

10


11/44

Measurand

Examples:


Tumor

Normal ECG

(Electrocardiography)

Abnormal ECG

11


12/44

Measurand

Examples:


Tumor

LiverTumor

Ultrasound ima e of tumor in liver

12


13/44

Measurand

Constrains:

Accessibility Vary with time and among patients

Safety

13


14/44

Measurand

Constrains:


Safety

14


15/44

Measurand

Constrains:


15


16/44

Measurand

Constrains:


Safety:

m a on o ex erna app e s gna s

Electrical safety

16


17/44




processing

Outputdisplay

Sensor: a device that converts the measurand

into a signal carrying information.

17


18/44

Sensor

Classification: according to the quantities to be

measured Thermal quantities

Mechanical uantities

Chemical quantities Radiation intensit

18


19/44

Sensor

Classification: according to the quantities to be




19


20/44

Sensor

Classification: according to the quantity to be




20


21/44

Sensor





Blood glucose meter

21


22/44

Sensor





22


23/44

Sensor

Static characteristics: the relationship between the

output signal and the measurand. Limit of detection: the lowest value of measurand

that can be detected by the sensor.

Sensitivity: the smallest change it can detect inthe quantity that it is measuring.

Repeatability: ability of a sensor to reproduce

output readings under the same input.

23


24/44

Sensor

Requirements:

Sensitive to the measured property Accurate

Stable and reliable

24


25/44




processing

Outputdisplay

Signal processing: amplifies, filters, or in any

other way changes the output of the sensor to

prepare signals suitable for display.

25


26/44

Si nal Processin

Biological signal magnitudes are low

ny measuremen nc u es no se

Parameter Range

ECG 0.5 4 mV

26


27/44

Si nal Processin

Biological signal magnitudes are low

ny measuremen nc u es no se

27


28/44

Si nal Processin

External: power lines, radio broadcast, cell phone

n erna : musc e no se, mo on ar ac

28


29/44

Si nal Processin

Signal filtering: separate noise from the desired

. . .

high frequency noise from low frequency signal.

Opposing inputs: if noise is known, it can be

v y u

from the signal.

29


30/44




processing

Outputdisplay

Output display: convey the information obtained

by the measurement in a meaningful way

(visual, audible)

30


31/44

uestion?

31


32/44

Thera eutic instrumentation

e n on: a ev ce a s use o rea a

disease or disorder. xamp e:

Ultrasound devices in therapy


33/44

Ultrasound

Ultrasound: sound wave with a frequency beyond the

upper limit of human hearing (>20 KHz).

33


34/44

Ultrasound

Ultrasound: sound wave with a frequency beyond the

upper limit of human hearing (>20 KHz).

34


35/44

Ultrasound in cancer treatment

-

to heat and destroy tumors.

35


36/44

Cancer treatment instrument

36


37/44

Clinical devices


38/44

Clinical a lications

Prostate cancer

Liver cancer Breast cancer

38


39/44

Ultrasound in sto bleedin

= 80% of early mortality in civilian injuries

= 50% of all battlefield mortality.

39


40/44


or a e ev ce a cou e use near e

site of trauma to reduce mortality from severe

oo oss.

40


41/44

Portable HIFU device

DisplayPower Supply and

Control Module

TherapyArray

Footswitch Imaging

ProbeDr. Myntti carrying a portable

image-guided HIFU System


42/44


1 cm

S


43/44

Summary

Diagnostic

Therapeutic

43

Hi i l P i 20th C


44/44

Historical Pers ective: 20th Centur

1903 ECG heart 1957 Ultrasound Imaging

diagnostic

1924 EEG brain waves

(anatomical imaging)

1970 CT Scanner 1928 ESU cauterizing

scalpel

(anatomical imaging)

1975 Inter aortic balloon

1928 Iron Lung

respiration assist

pump

1982 MRI (anatomical

uc ear e c ne

1956 Defibrillation 1984 Artificial Heart

1957 Pacemaker (1960

implantable)

-isotopes (physiological

44

302lect_diagtherapinstr

Documents