Harrison G H, Balcer-Kubiczek E K
Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore 21201.
Ultrasound Med Biol. 1991;17(6):627-32. doi: 10.1016/0301-5629(91)90033-s.
C3H/10T1/2 mouse embryo fibroblast cells grown as 1.2 cm diameter monolayers were assayed for cytotoxicity and neoplastic transformation following 30 min insonations with three types of pulsed ultrasound (US). Two of the US beams, with a repetition frequency of 1 kHz, center frequencies of 2.5 and 3.5 MHz and time-averaged intensities (ITA) of 31 and 6.7 mW/cm2, respectively, simulated biomedical pulse-echo imaging. The third US beam, with a repetition frequency of 5 kHz, center frequency of 2.5 MHz and ITA of 885 mW/cm2, simulated pulsed biomedical Doppler insonation. All three US beams exhibited negative pressure amplitudes in the range of 1 MPa over the cellular preparation. In order to provide uniform insonation for all exposed cells, all beams were unfocused; pressure amplitude variations did not exceed +/- 15% within a beam diameter of at least 1.5 cm, within which test samples of attached cells were confined. Ultrasound was delivered alone or in combination with x-rays (2 Gy, 240 kVp at 3.5 Gy/min given within 5 min before US) as a costressor. Under all treatment conditions, there was no significant affect of US on clonogenic survival or neoplastic transformation (cumulative probabilities ranging from 0.13 to 0.92).
将直径为1.2厘米的单层生长的C3H/10T1/2小鼠胚胎成纤维细胞，在用三种类型的脉冲超声（US）进行30分钟超声处理后，测定其细胞毒性和肿瘤转化情况。其中两种超声束，重复频率为1千赫兹，中心频率分别为2.5和3.5兆赫兹，时间平均强度（ITA）分别为31和6.7毫瓦/平方厘米，模拟生物医学脉冲回波成像。第三种超声束，重复频率为5千赫兹，中心频率为2.5兆赫兹，ITA为885毫瓦/平方厘米，模拟脉冲生物医学多普勒超声检查。所有三种超声束在细胞制剂上的负压幅度均在1兆帕范围内。为了给所有暴露的细胞提供均匀的超声照射，所有波束均未聚焦；在至少1.5厘米的波束直径内，压力幅度变化不超过±15%，附着细胞的测试样品被限制在该范围内。超声单独或与X射线联合（2戈瑞，240千伏峰值，在超声处理前5分钟内以3.5戈瑞/分钟的速度给予）作为共刺激因素。在所有治疗条件下，超声对克隆形成存活率或肿瘤转化均无显著影响（累积概率范围为0.13至0.92）。
