Combined Effects of Ionizing Radiation and Ultrasound on Malformation in ICR Mice at Organogenesis stage

Pregnant ICR mice were treated with 137Cs gamma-ray / ultrasound on day 8 of gestation. In combined treatments, pregnant mice were treated with both 1.5 Gy of radiation and $1.0W/cm^2$ ultrasound at time intervals of -1, 0, 1, 3 and 6 hours. The mortalities and external malformations were investigated on day 18 of gestation. The threshold dose of mortality induced by radiation on day 8 of gestation was between 0.5 and 1.0 Gy, and that which was induced by ultrasound was between 1.0 and $1.5W/cm^2$. The mortalities in the late-stage of gestation induced by combined treatment with radiation and ultrasound increased synergistically. The threshold dose of exencephaly and anophthalmia induced by radiation were between 0.5 and 1.0 Gy and between 1.0 and 1.5 Gy, respectively. Those of exencephaly and anophthalmia induced by ultrasound were between 1.0 and $1.5W/cm^2$ and more than $1.5W/cm^2$, respectively. In combined treatments, the incidence of exencephaly and anophthalmia were found to increase synergistically. In the mice treated with both agents at a time interval of one hour, the incidence of exencephaly and anophthalmia reached maximum levels.

태생 8일째인 임신한 생쥐에 137-Cs 감마선과 초음파를 조사하였다. 복합조사의 경우 임신한 생쥐는 1.5 Gy 방사선과 $1.0W/cm^2$ 초음파로 -1, 0, 1, 3, 6 시간 간격으로 조사하였다. 사망과 외부 기형은 태생 18일에 검진하였다. 방사선에 의한 태생 8일의 사망 임계값은 0.5에서 1.0 Gy사이였으며, 초음파는 1.0에서 $1.5W/cm^2$ 사이였다. 태생 후반기의 사망은 방사선과 초음파의 복합 치료에 의해 상승적으로 증가되었다. 방사선에 의한 뇌탈출기형 및 무안구증의 임계값은 각각 0.5에서 1.0Gy사이와 1.0에서 1.5Gy 사이였다 초음파에 의한 뇌탈출기형과 무안구증의 임계값은 각각 1.0에서 $1.5W/cm^2$ 사이와 $1.5W/cm^2$ 이상이었다. 복합치료의 경우는 뇌 탈출기형과 무안구증의 빈도가 상승적으로 증가하였다. 한 시간 간격으로 두 가지 치료를 받은 생쥐에서 뇌 탈출기형과 무안구증의 빈도가 최고치에 도달하였다.