DocumentCode :
410257
Title :
Effect of periodic shifting of relative phase in second-harmonic superimposition on inducing cavitation in vitro and in vivo
Author :
Kawabata, Ken-ichi ; Sugita, Nami ; Sasaki, Kazuaki ; Umemura, Shin-ichiro
Author_Institution :
Central Res. Lab., Hitachi Ltd., Kokubunji, Japan
Volume :
1
fYear :
2003
fDate :
5-8 Oct. 2003
Firstpage :
740
Abstract :
We reported that ultrasound exposure with second-harmonic superimposition (SHS) efficiently induced cavitational effects both in vitro and in vivo. This time we investigated the effect of periodical shifting of the relative phase on the cavitation induction by using SHS. In an aqueous solution, subharmonic emission intensity, a measure of cavitation intensity, obtained by using SH phase shifting with a shift pitch not larger than 1/2 π and a shift interval time not shorter than 30 ms was as much as that obtained with the optimum fixed SH phase. When exposed to tumor tissues subcutaneously implanted in mice, SH phase shifting with a shifting period larger than 10 ms was effective to suppress tumor growth, which roughly agree with in vitro results. This result may be important for the application of SHS to in vivo treatment in which it is difficult to maintain the relative phase in a target tissue constant because of movements and biophysical changes.
Keywords :
biological effects of fields; cavitation; cellular biophysics; cellular effects of radiation; tumours; ultrasonic effects; 10 ms; 30 ms; biophysical changes; cavitation induction; cavitation intensity; cavitational effects; periodic shifting; phase shifting; second harmonic superimposition; shift interval time; shift pitch; subharmonic emission intensity; tumor growth; tumor tissues; ultrasound exposure; vivo treatment; In vitro; In vivo; Laboratories; Mice; Neoplasms; Phase measurement; Signal generators; Time measurement; Ultrasonic imaging; Ultrasonic variables measurement;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Ultrasonics, 2003 IEEE Symposium on
Print_ISBN :
0-7803-7922-5
Type :
conf
DOI :
10.1109/ULTSYM.2003.1293507
Filename :
1293507
Link To Document :
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