The lesions generated by high intensity ultrasound were studied in transparent tissue phantoms premixed with and without ultrasound contrast agents (UCA) at 1.1- and 3.5-MHz acoustic waves. Generation of small bubbles was observed at the very beginning of exposure, whereas cigar-shaped thermal lesions began to form at the focus after a delay. After further heating, boiling occurred and changed the lesion to tadpole-shape, with advancement toward the transducer. Broadband noise was detected in phantoms with UCA initially. UCA also lowered the pressure threshold and enlarged the lesion. Although thermal and cavitation effects are believed to be both important in lesion formation, tadpole-shaped transformation results from boiling activity.

1.
Bailey
,
M. R.
,
Couret
,
L. N.
,
Sapozhnikov
,
O. A.
,
Khokhlova
,
V. A.
,
ter Harr
,
G.
,
Vaezy
,
S.
,
Shi
,
X.
,
Martin
,
R.
, and
Crum
,
L. A.
(
2001
). “
Use of overpressure to assess the role of bubbles in focused ultrasound lesion shape in vitro
,”
Ultrasound Med. Biol.
27
,
695
708
.
2.
Chapelon
,
J. Y.
,
Ribault
,
M.
,
Vernier
,
F.
,
Souchon
,
R.
, and
Gelet
,
A.
(
1999
). “
Treatment of localized prostate cancer with transrectal high intensity focused ultrasound
,”
Eur. J. Ultrasound
9
,
31
38
.
3.
Chavier
,
F.
,
Chapelon
,
J. Y.
,
Gelet
,
A.
, and
Cathignol
,
D.
(
2000
). “
Modeling of high-intensity focused ultrasound-induced lesions in the presence of cavitation bubbles
,”
J. Acoust. Soc. Am.
108
,
432
440
.
4.
Clarke
,
R. L.
, and
ter Haar
,
G. R.
(
1997
). “
Temperature rise recorded during lesion formation by high-intensity focused ultrasound
,”
Ultrasound Med. Biol.
23
,
299
306
.
5.
Daum
,
D. R.
,
Smith
,
N. B.
,
King
,
R.
, and
Hynynen
,
K.
(
1999
). “
In vivo demonstration of noninvasive thermal surgery of the liver and kidney using an ultrasonic phased array
,”
Ultrasound Med. Biol.
25
,
1087
1098
.
6.
Fry
,
F. J.
,
Sanghvi
,
N. T.
,
Foster
,
R. S.
,
Bihrle
,
R.
, and
Hennige
,
C.
(
1995
). “
Ultrasound and microbubbles: their generation, detection and potential utilization in tissue and organ therapy—experimental
,”
Ultrasound Med. Biol.
21
,
1227
1237
.
7.
He, S. X., Xiong, L. L., Yao, S. S., Yu, J. S., Lan, J. M. X., He, C. J., Shan, S. S., Zeng, J. Q., Zang, Y., and Du, R. U. (2001). “Early clinical study of high intensive focused ultrasound in the treatment of 160 patients with advanced abdominal and pelvic malignant tumors and hypertrophy,” Chin. Med. J. (Engl) 114, http://www.cmj.org/heshengxu2.htm.
8.
Holt
,
R. G.
, and
Roy
,
R. A.
(
2001
). “
Measurements of bubble-enhanced heating from focused, MHz-frequency ultrasound in a tissue-mimicking material
,”
Ultrasound Med. Biol.
27
,
1399
1412
.
9.
Lafon, C., Vaezy, S., Nobel, M., Kaczkowski, P. J., Martin, R., and Crum, L. A. (2002). “A new synthetic tissue-mimicking phantom for high intensity focused ultrasound,” 2001 Proc. IEEE Ultrason. Symp. 2, 1295–1298.
10.
Meaney
,
P. M.
,
Cahill
,
M. D.
, and
ter Haar
,
G. R.
(
2000
). “
The intensity dependence of lesion position shift during focused ultrasound surgery
,”
Ultrasound Med. Biol.
26
,
441
450
.
11.
Sanghvi
,
N. T.
,
Foster
,
R. S.
,
Bihrle
,
R.
,
Casey
,
R.
,
Uchida
,
T.
,
Phillips
,
M. H.
,
Syrus
,
J.
,
Zaitsev
,
A. V.
,
Marich
,
K. W.
, and
Fry
,
F. J.
(
1999
). “
Noninvasive surgery of prostate tissue by high intensity focused ultrasound: An updated report
,”
Eur. J. Ultrasound
9
,
19
29
.
12.
ter Haar
,
G. R.
(
2001
). “
High intensity focused ultrasound for the treatment of tumors
,”
Echocardiography
18
,
317
322
.
13.
Tran, B. C., Seo, J., Fowlkes, J. B., and Cain, C. A. (2002). “Microbubble enhanced threshold reductions for tissue damage using high intensity ultrasound,” 2001 Proc. IEEE Ultrason. Symp. 2, 1389–1392.
14.
Vaezy
,
S.
,
Shi
,
X.
,
Martin
,
R. W.
,
Chi
,
E.
,
Nelson
,
P. I.
,
Bailey
,
M. R.
, and
Crum
,
L. A.
(
2001
). “
Real-time visualization of high-intensity focused ultrasound treatment using ultrasound imaging
,”
Ultrasound Med. Biol.
27
,
33
42
.
15.
Watkin
,
N. A.
,
ter Haar
,
G. R.
, and
Rivens
,
I.
(
1996
). “
The intensity dependence of the site of maximal energy deposition in focused ultrasound surgery
,”
Ultrasound Med. Biol.
22
,
483
491
.
16.
Wu
,
F.
,
Chen
,
W. Z.
,
Bai
,
J.
,
Zou
,
J. Z.
,
Wang
,
Z. L.
,
Zhu
,
H.
, and
Wang
,
Z. B.
(
2001
). “
Pathological changes in human malignant carcinoma treated with high-intensity focused ultrasound
,”
Ultrasound Med. Biol.
27
,
1099
1106
.
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