YuriyYuriy ZorenkoZorenko*Electronic Department, Ivan Franko National University of

Lviv, Ukraine** Institute of Physics, Jan Dlugosz University in

Czestochowa, Poland

1. Modern Materials Engineering.2. Luminescent Materials in Medicine and Protection of Health

Ultrasound and ultrasound materialUltrasound and ultrasound materialin medicinein medicine

Milestone of electronic materials in medicine and protection ofMilestone of electronic materials in medicine and protection of healthhealth

Sender /receiver

Reflected wave

Object

Original wave

20 Hz-20 KHz

1MHz-18 MHz

UltrasoundUltrasound PhysicsPhysics

Diagnostic Ultrasound X-or γ- rays radiology

wave type longitudinal mechanical waves electromagnetic wavestransmissionrequirements elastic medium no medium

generation stressing the medium accelerating electriccharges

velocity depends on the mediumthrough which it propagates

It is relatively constant: 299,792.456.2 m/s

similar waves seismic, acoustic radio, light

MainMain differencesdifferences betweenbetween UltrasoundUltrasound andand XX--raysrays

Velocity of sound in some Biological Materials

VelocityVelocity ofof soundsound inin somesome BiologicalBiological MaterialsMaterialsMaterial Velocity of Sound (m/s) Impedance (Rayl x 10-6)

Air 330 0.0004Fat 1450 1.38

Water 1480 1.48Average Human

Soft Tissue1540 1.63

Brain 1540 NALiver 1550 1.65

Kidney 1560 1.62Blood 1570 1.61

Muscle 1580 1.7Lens of eye 1620 NASkull Bone 4080 7.8

1.1. FFrequencyrequency (ν> 20 kHz)2. Wavelength (λ ~ 1/ν)

3. 3. VelocityVelocity ofof ssoundound in mediain media c c (m/s)(m/s)4. 4. ImpedanceImpedance Z = pZ = pc (c (ρρ--density of mediadensity of media))

Ultrasound and animals

Bats (nietoperzy) use ultrasounds to move in the darkness. Bats use a varietyof ultrasonic techniques (echolocation) to detect their prey. They can detectfrequencies up to 100 kHz.

Insects

Dogs hear ultrasound in range of 18–22 kHz.

Dolphins have their own natural sonar system

Fish - hear ultrasound in range of 4-180 kHz.

Horses

Cows

Something from history of ultrasound diagnostic in medicine

Vidoson-635, 1968

An ultrasound examinationin East Germany, 1990

1958 – fist application of ultrasound in medicineIanIan DonaldDonald (University of Glasgow, GB)

Novel Sonoline equipmentSonoline-3000, 1982

Equipment for US diagnosticEquipment for US diagnostic

Reflection of sound on the border of two mediaReflection of sound on the border of two media

Ultrasound diagnostic systemPhysical basis

Z – impedance of mediumc- velocity of sound in mediumρ - density of medium

R =1 - total reflection (between the air and tissue)

R = 0.01-1 % - typical for softly plant tissue

R =0 reflection absence

Reflection factor

Ultrasound Basic physics. Reflection. Wave resistence

⇒Air is major absorber

⇒Usege special bodygell (99% water)

Small absorber:BoneEndoprotese Gallstone

Ideal case is the reflection of 1 % part of ulrasound wave ( R=0,01)

is smallAbsence ofreflection

Totalreflection

Is large

Water

Bone

Air

Muscle

Water

UUltrasonographyltrasonography is widely used in medicine. It is possible to perform bothdiagnosis and therapeutictherapeutic proceduresprocedures, using ultrasound to guide interventionalprocedures (for instance biopsies or drainage of fluid collections).

UUltrasonographyltrasonography typically use a hand-held probe (called a transducer(transduktor) that is placed and moved directly on body of the patient.

The choice of frequency is a compromize between spatialspatial resolutionresolution of the imageand imagingimaging depthdepth: lower frequencies produce lessless resolutionresolution butbut imageimage deeperdeeperinto the body.

Typical diagnostic sonographic scanners operate in the of 11--18 18 MhzMhz range.5050--100100 MHzMHz has been used in a technique known as biomicroscopybiomicroscopy in specialregions, e.g. like the anterior chamber of eye.

Sonography is effective for imaging soft tissues of the body. Superficialstructures such as muscles, tendons, testes, breast and the neonatal brain areimaged at a higher frequency of 7-18 MHz, which provides better axial and lateralresolution.

Deeper structures such as liver and kidney are imaged at a lower frequency 1-6 MHz with lower axial and lateral resolution but greater penetration.

Parameters of ultrasound at medical diagnostic

Frequency and Resolution (axial resolution)

This is for linear array transducers with parallel beams

MHz Axial resolution Lateral resolution Resolution %

3.0 1.1 mm 2.8 mm 35.9 %4.0 0.8 mm 1.5 mm 60.9 %5.0 0.6 mm 1.2 mm 77.8 %7.5 0.4 mm 1.0 mm 100 %10.0 0.3 mm 1.0 mm 107.7 %

Modes of sonographySeveral different modes of ultrasound areused in medical imaging:

AA--modemode: A-mode is the simplest type ofultrasound. A single transducer scans a line through the body with the echoesplotted on screen as a function of depth.Used mainly for therapy.

BB--modemode: A linearlinear arrayarray ofof transducerstransducerssimultaneously scans a plane through thebody that can be viewed as a two-dimensional image on screen.

MM--modemode: A rapid sequence of B-modescans whose images follow each other insequence on screen enables to see andmeasure range of motion, as the organboundaries that produce reflections moverelative to the probe.

Ultrasound diagnosticUltrasound diagnosticPhysical basic. Doppler effect

f1 – frequency of fall wavef2 – frequency of reflected waveC- velocity of sound in mediaν – velocity of object

DopplerDoppler modemode: This mode used of the Doppler effect in measuring andvisualizing bloodblood flowflow

ColorColor dopplerdoppler: Velocity information is presented as a color coded overlay on topof a B-mode image

PulsedPulsed wavewave (PW) (PW) dopplerdoppler: Doppler information is sampled from only a smallsample volume (defined in 2D image), and presented on a time

DuplexDuplex:: a common name for the simultaneous presentation of 2D and (usually) PW doppler information.

Doppler_mitral_valve

ModesModes ofof sonographysonography

UltrasoundUltrasound examinationsexaminations can help to diagnose a variety of conditions and toassess organ damage following illness. Ultrasound is used to help evaluate symptoms such as:

• pain (ból )• swelling (guz)• infection (infekcja)

Ultrasound is a useful way of examining of the body's internal organs:

• heart and blood vessels, including the abdominal aorta and its majorbranches• liver (wątroba )• gallbladder (woreczek żółciowy )• spleen (śledziona)• pancreas (trzustka)• kidneys (nerka )• bladder (pęcherz)• uterus(macica ), ovaries (jajniki), and unborn child (fetus (płód) in pregnantpatients• eyes• thyroid and parathyroid glands

Application of ultrasoundApplication of ultrasound

Gallbladder (woreczek żółciowy )

UltrasoundUltrasound imagesimages::

Liver (wątroba )

Kidney (nerka )

Ultrasound is also used to:• scrotum (moszna)• guide procedures such as needle biopsies, in which needles areused to extract sample cells from an abnormal area for laboratorytesting. • image the breasts (pierśi) and to guide biopsy of breast cancer• diagnose a variety of heart conditions and to assess damage aftera heart attack or diagnose for valvular heart disease. Doppler ultrasound images can help the physician to see andevaluate:• blockages to blood flow (such as clots). • narrowing of vessels• tumors (guzy) and congenital malformation.With knowledge about the speed and volume of blood flow gainedfrom a Doppler ultrasound image, the physician can often determinewhether a patient is a good candidate for a procedure likeangioplasty.

Special application of ultrasoundSpecial application of ultrasound

Examples of ultrasound image and applicationsExamples of ultrasound image and applications

A fetus in its mother's womb, viewed in a sonogram (brightness scan)

Geometry of ultrasound image

2D geometry 3D geometry

Construction of Sonder and Receivers

Best linear scanner is complet in form of array of from crystals (~400 St.)

body

scan-line principles of linear array

sound beam

SonderSonder ((TransducersTransducers))Piezoelectric materials are used in electromechanical devices. In the case of amicrophone transducer, sound of a particular frequency results in a strain in thematerial, which in turn induces an electric field. Similarly in speakers, a voltage input into the piezoelectric material can beconverted into a mechanical strain, such as in a speaker transducer.

Construction of Sonder.Dynamics focusing in separate Matrix-Array

Linear Array Transducer

Construction of SonderLayer thickness is the key of scanning system

Ultrasonic testing is a type of nondestructive testing commonly used to find flawsin materials and to measure the thickness of objects. Frequencies of 2 to 10 MHzare common but for special purposes other frequencies are used. Inspection maybe manual or automated and is an essential part of modern manufacturingprocesses. Most metals can be inspected as well as plastics and aerospacecomposites. Lower frequency ultrasound (50–500 kHz) can also be used toinspect less dense materials such as wood, concrete (beton) and cement.

Non-destructive testing

Industrial application of ultrasound

Ultrasonic cleaning

Industrial application of ultrasound

Ultrasonic Ultrasonic cleanerscleaners, sometimes mistakenly called supersonic cleaners, are usedat frequencies from 20 20 toto 40 40 kHzkHz for jewellery, lenses and other optical parts, watches, dental instruments, surgical instruments, diving regulators andindustrial parts. An ultrasonic cleaner works mostly by energy released from thecollapse of millions of microscopic cavitations near the dirty surface. The bubblesmade by cavitation collapse forming tiny jets directed at the surface.

Ultrasound Identification (USID)

Ultrasound Identification (USID) is a Real Time Locating System (RTLS) or IndoorPositioning System (IPS) technology used to automatically track and identify thelocation of objects in real time using simple, inexpensive nodes (badges/tags) attached to or embedded in objects and devices, which then transmit anultrasound signal to communicate their location to microphone sensors

Ultrasound materials

Piezoelectricity – invention in 1880 by brothers Curie.Piezoelectricity is the ability of some materials (crystals and certain ceramics)

to generate an electrical potential in response to applied mechanical sress.

The piezoelectric effect is reversible. The materials exhibiting the directdirectpiezoelectricpiezoelectric effecteffect (the production of electricity when stress is applied) alsoexhibit the converseconverse piezoelectricpiezoelectric effecteffect (the production of stress when anelectric field is applied - electromechanical effectelectromechanical effect).

SiO2 crystals

Ultrasound diagnostic systemPhysical basis. Piezoeffect

-

+

+

-

+

-

-

+

+

-

+

-

+A pushing force: compression A pulling force: tension

+

-

-

+

+

-

+

-

The unit cell of crystal silicon dioxide

Si

O

Polarization

-

+

+

-

+

-

+

-

The Piezoelectric Effect

Crystal

Current Meter= 0

+ - + - + -

+ - + - + -Charges canceleach other, sono current flow

Crystal material at rest: No forces applied, so the current flow is 0

The Piezoelectric Effect

Crystal

Current Meterdeflects in + direction

- - - - -

+ + + + +

Crystal material with forces applied in direction of arrows………..

Due to properties of symmetry,charges are net + on one side & net - on the opposite side: crystal gets thinner and longer

Force

-

+

+

-

+

-

+

-

The Piezoelectric Effect

Crystal

Current Meterdeflects in -direction

+ + + +

- - - - -

…. Changes the direction of current flow, and the crystal getsshorter and fatter.

Changing the direction of theapplied force………..

Force

-

+

+

-

+

-

Electromechanical nature Electromechanical nature of piezoelectric materialof piezoelectric material

• In general, if you deform a piezocrystal by applying a force, you will get charge separation: Think of a simple battery.

• Taking it one step further, what would happen to the crystal if you applied an electrical force that results in the exact same current flow from the proceeding circuit?

The electromechanical effectThe electromechanical effect

Crystal

…. With the switch open, the crystal material is now at rest again:the positive charges cancel the negative charges.

Now, replace the current meter with a power source capableof supplying the same current indicated by the meter….

+ - + - + -

+ - + - + -

switch

power sourcecharges cancel

The electromechanical effect

Crystal

…. and, the crystal should get shorter and fatter.

When the switch is closed, and you apply the exact amount of power to get the same current that resulted when you squeezedthe crystal, the crystal should deform by the same amount!!

power source(battery)

- side

+ side+ + + +

- - - - -

The electromechanical effect

Crystal

…. the crystal should get longer and skinnier.

What will happen if you switched the battery around??

power source(battery)

+ side

- side- - - - -

+ + + + +

Summary of the Summary of the Piezoelectric & Electromechanical EffectPiezoelectric & Electromechanical Effect

• A deformation of the crystal structure (eg: squeezing it) will result in an electrical current.

• Changing the direction of deformation (eg: pulling it) will reverse the direction of the current.

• If the crystal structure is placed into an electrical field, it will deform by an amount proportional to the strength of the field.

• If the same structure is placed into an electrical field with the direction of the field reversed, the deformation will be opposite.

Piezoelectric materialsPiezoelectric materials

dd-- piezoelectricpiezoelectric constantconstant of materials of materials -- inducedinduced strainstrain // unitunit electricelectric fieldfield appliedapplied;;k k -- electromechanicalelectromechanical couplingcoupling factorfactor - mechanical energy converted / electricenergy input

A2+ B4+O3

A = Ba, PbB= Ti, Zr, Sn

Structure of Perovskite

Novel ultrasound materialsNovel ultrasound materials

Piezoelectric materials with a perovskite structure exists in two crystallographicforms. Below the Curie temperature they have a tetragonal structure. In the tetragonalstate, each unit cell has an electric dipole, i.e. there is a small charge differentialbetween each end of the unit cell.

Above the Curie temperature they transform into a cubic structure.

A mechanical deformation (such as a compressive force) can decrease theseparation between the cations and anions which produces an internal field orvoltage.

+ + + +

- - - - + - + -

+ - + -

Ferroelectric. BaTiOFerroelectric. BaTiO33

Ultrasound materials. PbTiOPbTiO33--PbZrOPbZrO3 3 (PZT)(PZT)

TCTemperatureCurie

ferrimagnetic

Antiferri-magnetic

paramagnetic

SiOSiO2 2 elements working at 50 KHzelements working at 50 KHz

Length: 52.0 mm (2.05”)

Width: 10.4 mm (0.41”)

Thickness: 5.2 mm (0.20”)

Electrode W.: 9.0 mm (0.35”)

w

t

l

Elec.

Piezoelectric crystals and ceramics

Literatura

A. Śliwiński, Ultradźwięki i ich zastosowanie, PWT 2001.J. Golanowski, T. Gudra, Podstawy techniki ultradźwięków,

P.Wr. 1990.J. Golanowski, T. Gudra, Pomiarowe urządzenia

ultradźwięków, P.Wr. 1990.A. Nowicki, Podstawy ultrasonografii dopplerowskiej, PWN W-

wa 1995.

Дякую за увагу !

Thank you for attention !

Dziekuje za uwage!