清水 哲也¹, 田中 邦雄^{1, 2}

Tetsuya SHIMIZU¹, Kunio TANAKA^{1, 2}

¹旭川医科大学医学部産科婦人科学教室, ²旭川医科大学附属実験実習機器センター

¹Department of Obstetrics and Gynecology, Asahikawa Medical College, ²Central Research Laboratory of Medical Education and Experiment Asahikawa Medical College

キーワード : pulsed ultrasound, safety, hamster, fetus

Ultrasound diagnostic instruments have been widely applied in obstetrics. The chance of the exposure to ultrasound at the early stage of gestation has been increased recently. Therefore, the effect of ultrasound, especially pulsed ultrasound, on fetuses must be clarified quantitatively.
In this paper, the Chinese hamster (closed colony) maintained at Asahikawa Medical College was used to investigate the teratologic effect of pulsed ultrasound. On day 8, 9 and 10 of gestation, pregnant animals were exposed to pulsed ultrasound with the frequency of 2 MHz, the pulse width of 3 μs and the repetition of 500 Hz. Furthermore, X-ray with the intensity of 200 rad was exposed to pregnant Chinese hamster (on day 8 - 12 of gestation) to clear the difference of the sensitivity in the species of animals to the external physical energy.
From these experiments, external malformations were not observed in sonicated groups of the peak intensity of 10 W/cm² and 62.7 W/cm². However, it was clear that the sensitivity to x-ray exposure on the Chinese hamster used in this experiment differed from mice or rats. These results show that further investigations on the difference in the species of experimental animals are necessary to clarify the teratologic effect of pulsed ultrasound.