yufeng zhou and xiaobin wilson gao school of mechanical & aerospace engineering nanyang...
TRANSCRIPT
Bubble Dynamics with the Progress of Histotripsy
Yufeng Zhou and Xiaobin Wilson Gao
School of Mechanical & Aerospace Engineering
Nanyang Technological University
IntroductionUltrasound therapy is an emerging
modality in clinics;
High-intensity low-duration ultrasound pulse can be implemented in drug delivery, thrombolysis, etc.
Histotripsy can be used to erode soft tissue noninvasively;
Bubble dynamics plays an important role in such application.
Experiment Setup
Lesion GrowthN = 1 N = 2 N = 5 N = 10
N = 50 N = 100
3.3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W
N = 20 N = 70
Passive Cavitation Detection
Number of pulses
0 10 20 30 40 50 60 70 80 90 100
Pea
k-to
-pea
k P
CD
sig
nal
(V)
0.0
0.1
0.1
0.2
0.2
0.3
0.3
PCD
Lig
ht T
ran
smis
sion
(V
)
0.3
0.4
0.4
0.4
0.5
0.5
0.6
Light transmission
0 2 4 6 8 10 12 14 16 18 200
0.02
0.04
0.06
0.08
0.1
0.12
Time (ms)
PC
D
(V)
0 2 4 6 8 10 12 14 16 18 200
0.02
0.04
0.06
0.08
0.1
0.12
Time (ms)
PC
D
(V)
1st pulse
100th pulse
3.3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W output
Number of pulses
0 10 20 30 40 50 60 70 80 90 100
Pea
k-to
-Pea
k P
CD
sig
nal
(V)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
10ms 20ms 30ms
Effect of Pulse Duration
3.3 MHz, 1 Hz pulse repetition rate, 150 W
Lesion Growth
1.1 MHz, 100 ms burst, 1 Hz pulse repetition rate, 150 W
N = 1 N = 2 N = 5 N = 10
N = 20 N = 50 N = 70 N = 100
Effect of Frequency
Number of pulses
0 10 20 30 40 50 60 70 80 90 100
Pea
k-to
-pea
k P
CD
sig
nal
(V)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
60 ms 80 ms 100 ms 120 ms
1.1 MHz, 1 Hz pulse repetition rate, 150 W
Ex Vivo Results
3.3 MHz, 1 Hz pulse repetition rate, 150 W
Ex Vivo PCD
Number of pulses
0 10 20 30 40 50 60 70 80 90 100
Pea
k-t
o-p
eak
PC
D s
ign
al (
V)
0.0
0.1
0.2
0.3
0.4
20ms 30ms
3.3 MHz, 1 Hz pulse repetition rate, 150 W output
B-Mode Sonography
3.3 MHz, 30 ms burst, 1 Hz pulse repetition rate, 150 W output
N = 1 N = 5
N = 50 N = 100
ConclusionsCharacteristics of bubble dynamics vary
with the progress of the ultrasound therapy;
Ultrasound parameters (i.e., burst duration, frequency, target type) have great influence on the bubble dynamics, thermal effects, and consequent lesion formation;
Appropriate combination of mechanical and thermal effect would broaden the application;
Monitoring bubble dynamics could control the ultrasound therapy effectively and efficiently.
