pulse-echo ultrasound pulsing characteristics and duty factor instrumentation beam former pulse...
TRANSCRIPT
![Page 1: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/1.jpg)
CHAPTER3PULSE-ECHO UL-
TRASOUND IN-STRUMENTATION
윤성수
![Page 2: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/2.jpg)
CONTENTS▣ Pulse-Echo Ultrasound □ Pulsing Characteristics and Duty Factor
▣ Instrumentation □ Beam former □ Pulse Transmitter □ Receiver ▣ Ultrasound scanning
▣ Scanners □ Linear array transducers □ Curvilinear array transducers □ Phased array transducers
▣ Frame rate and scanning speed limitations
![Page 3: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/3.jpg)
PULSE-ECHO ULTRASOUND
□ The Range Equation
□ T : Pulse Echo travel time
□ c : speed of ultrasound in target material
2DT
c
![Page 4: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/4.jpg)
PULSE-ECHO ULTRASOUND
□ Pulse Duration Pulse Duration↓ ⇒ Axial resolution↑ □ Pulse repetition period : Wait for Echo pulse PP↑ ⇒ frame rate ↓
□ Duty Factor
![Page 5: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/5.jpg)
INSTRUMENTATION
![Page 6: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/6.jpg)
BEAM FORMER
![Page 7: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/7.jpg)
BEAM FORMER
□ 구현 방식 ▶ Analog vs Digital
□ Beam steering and focusing (pulse delay sequence) ▶ transmit focusing ▶ dynamic focusing of received echo ▶ controls the beam direction
![Page 8: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/8.jpg)
BEAM FORMER
□ 구현 방식 ▶ Analog ① 반사신호를 한 곳에 모으는
시간이 20~40ns 로 편차가 커 선명한 의료영상 구현 어려움
② 인체 한 부위의 초점 위치를 제외한 나머지 부위에 대해선 수신 focusing 을 구현할 수 없음
![Page 9: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/9.jpg)
BEAM FORMER
□ 구현 방식▶ Digital ① Stable : external factor
(ex. temperature)
② programmability
③ wide range of signal fre-quency
![Page 10: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/10.jpg)
BEAM FORMER
□ Beam steering and focusing (pulse delay sequence) ▶ transmit focusing ▶ dynamic focusing of received echo ▶ controls the beam direction
arraytransmitter
focusing
different time delay
Transmit focusing
![Page 11: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/11.jpg)
BEAM FORMER
□ Beam steering and focusing (pulse delay sequence) ▶ transmit focusing ▶ dynamic focusing of received echo ▶ controls the beam direction
Dynamic focusing of received echo
different time delayarraytrans-ducer
same delayedsignal
focused signal
reflector
![Page 12: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/12.jpg)
BEAM FORMER
□ Beam steering and focusing (pulse delay sequence) ▶ transmit focusing ▶ dynamic focusing of received echo ▶ controls the beam direction
Controls the beam direction
![Page 13: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/13.jpg)
PULSE TRANSMITTER
![Page 14: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/14.jpg)
PULSE TRANSMITTER
□ Pulse transmitter ▶ provide electrical signals for exciting transducer
① Transmit power ↑
② Higher intensity sound wave
③ Higher amplitude echo signal
④ Appear brighter and weaker reflectors In the display But acoustical exposure to the patient↑
![Page 15: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/15.jpg)
PULSE TRANSMITTER
□ Pulse transmitter ▶ provide electrical signals for exciting transducer
Low output power (MI is 0.2) High output power (MI is 0.8)
![Page 16: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/16.jpg)
RECEIVER
![Page 17: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/17.jpg)
RECEIVER
□ Procedure of the receiver
![Page 18: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/18.jpg)
AMPLIFY(RECEIVER)
□ PreamplifierBoosts echo signalsprotect the receiver from high-voltage
□ problem : amplify noise
![Page 19: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/19.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ Overall gain control : Increase amplification at all depths
High gainLow gain
![Page 20: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/20.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ Overall gain control : Increase amplification at all depths
High gainLow gain
![Page 21: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/21.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ Swept gain or TGC(time gain compensation) : Attenuation compensation depending depth
![Page 22: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/22.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ Swept gain or TGC ▶ Slider bar TGC control
![Page 23: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/23.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ 3-Knob TGC control
![Page 24: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/24.jpg)
COMPENSATE(RECEIVER)
□ Gain adjustments ▶ Internal time-varied gain : automatically set swept gain
▶ Lateral gain
![Page 25: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/25.jpg)
COMPENSATE(RECEIVER)
□ Dynamic frequency tuning ▶ Higher frequency sound waves are attenuated more rapidly and penetrate less deeply than lower frequencies.
![Page 26: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/26.jpg)
COMPENSATE(RECEIVER)
□ Dynamic frequency tuning ▶ Higher frequency sound waves are attenuated more rapidly and penetrate less deeply than lower frequencies.
▶ shallow regions higher frequencies deeper regions lower frequencies
![Page 27: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/27.jpg)
DYNAMIC RANGE AND COMPRESSION(RECEIVER)
□ Dynamic range ▶ Limited input signal amplitude range to respond effectively ▶ Threshold < Input signal < Saturation
![Page 28: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/28.jpg)
DYNAMIC RANGE AND COMPRESSION(RECEIVER)
□ Log compression ▶ Receiver : 100~120dB Memory : 40~45dB Monitor(contrast) : 20~30dB
Log Compression
![Page 29: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/29.jpg)
DYNAMIC RANGE AND COMPRESSION(RECEIVER)
□ Log compression
▶ Low dynamic range : High contrast High dynamic range : Low contrast
![Page 30: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/30.jpg)
DEMODULATION(RECEIVER)
□ Demodulation ▶ Convert the amplified echo signal into a single pulse
Input signal → rectification → smoothing
![Page 31: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/31.jpg)
REJECT(RECEIVER)
□ Reject ▶ reject eliminates both low level electronic noise and low level echoes
![Page 32: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/32.jpg)
REJECT(RECEIVER)
□ Reject ▶ Adaptive threshold processing
![Page 33: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/33.jpg)
ULTRASOUND SCANNING
□ A – mode(amplitude mode) ▶ shows echo amplitude versus reflector distance ▶ only presents echo data from a single beam line(limited uses)
![Page 34: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/34.jpg)
ULTRASOUND SCANNING
□ A – mode(amplitude mode) ▶ shows echo amplitude versus reflector distance ▶ only presents echo data from a single beam line(limited uses) ▶ ophthalmological applications
![Page 35: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/35.jpg)
ULTRASOUND SCANNING
□ B – mode(brightness mode) ▶ echo signals are converted to intensity-modulated dots ▶ brightness ∝ echo signal amplitude
![Page 36: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/36.jpg)
ULTRASOUND SCANNING
A - mode
B - mode
![Page 37: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/37.jpg)
ULTRASOUND SCANNING
□ M – mode(motion mode) ▶ by slowly sweeping a B-mode trace across a screen ▶ depth on one axis and time on an orthogonal axis
![Page 38: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/38.jpg)
ULTRASOUND SCANNING
□ M – mode(motion mode) ▶ velocity of a reflector is estimated from
∆t∆d
![Page 39: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/39.jpg)
ULTRASOUND B-MODE SCANNING
□ Image build-up ▶ called 2-D image ▶ echoes are positioned along a line that corresponds to the beam axis
![Page 40: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/40.jpg)
SCANNERS
□ Linear array transducers ▶ small rectangular elements lined up side by side ▶ parallel beam line
![Page 41: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/41.jpg)
SCANNERS
□ Linear array transducers ▶ small rectangular elements lined up side by side
![Page 42: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/42.jpg)
SCANNERS
□ Convex array transducers ▶ same principles as a linear array ▶ beam lines are not parallel, emerge at different angles
![Page 43: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/43.jpg)
SCANNERS
□ Convex array transducers ▶ larger imaged field than linear array
![Page 44: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/44.jpg)
SCANNERS
□ Phased array transducers ▶ electronically steered at various angles ▶ electronic focusing
![Page 45: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/45.jpg)
SCANNERS
□ Phased array transducers ▶ through the intercostal (small entrance window) ▶ cardiac imaging
![Page 46: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/46.jpg)
SCANNERS
□ Mechanical scan ▶ two to four separate transducers positioned in different locations on the rim of rotating wheel
![Page 47: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/47.jpg)
FRAME RATE AND SCANNING SPEED LIMITA-TIONS
□ Maximum frame rate ▶ D : depth C : speed of sound in tissue (1540 m/s) N : the number of lines
213line
DT s D
C
frame lineT N T
max
1 1 77000 /
13 ( )frame
sFR
T s N D N D cm
![Page 48: Pulse-Echo Ultrasound Pulsing Characteristics and Duty Factor Instrumentation Beam former Pulse Transmitter Receiver Ultrasound scanning Scanners Linear](https://reader036.vdocuments.net/reader036/viewer/2022062404/5518a344550346c31f8b4984/html5/thumbnails/48.jpg)
FRAME RATE AND SCANNING SPEED LIMITA-TIONS
□ Maximum frame rate ▶ D : depth C : speed of sound in tissue (1540 m/s) N : the number of lines
D ↑ ⇒ Frame Rate↓
N↑ ⇒ Frame Rate↓
N↑ ⇒ Frame Rate↓Smaller image sizeResolution 유지