Department of Electrical and Computer Engineering, Ryerson University, 350 Victoria Street, Toronto, Ontario M5B 2K3, Canada.
J Acoust Soc Am. 2010 Aug;128(2):894-902. doi: 10.1121/1.3455795.
The measurement of the ultrasound backscatter from individual micron-sized objects such as cells is required for various applications such as tissue characterization. However, performing such a measurement remains a challenge. For example, the presence of air bubbles in a suspension of cells during the measurements may lead to the incorrect interpretation of the acoustic signals. This work introduces a technique for measuring the ultrasound backscatter from individual micron-sized objects by combining a microinjection system with a co-registered optical microscope and an ultrasound imaging device. This allowed the measurement of the ultrasound backscatter response from a single object under optical microscope guidance. The optical and ultrasonic data were used to determine the size of the object and to deduce its backscatter responses, respectively. In order to calibrate the system, the backscatter frequency responses from polystyrene microspheres were measured and compared to theoretical predictions. A very good agreement was found between the measured backscatter responses of individual microspheres and theoretical predictions of an elastic sphere. The backscatter responses from single OCI-AML-5 cells were also investigated. It was found that the backscatter responses from AML cells are best modeled using the fluid sphere model. The advantages, limitations, and future applications of the developed technique are discussed.
需要对单个微米大小的物体（如细胞）的超声背向散射进行测量，这在组织特征化等各种应用中是必要的。然而，进行这样的测量仍然是一个挑战。例如，在测量过程中细胞悬浮液中存在气泡可能导致对声信号的不正确解释。本工作介绍了一种通过将微注射系统与共配准的光学显微镜和超声成像设备相结合来测量单个微米大小的物体的超声背向散射的技术。这使得可以在光学显微镜引导下测量单个物体的超声背向散射响应。光学和超声数据分别用于确定物体的大小和推断其背向散射响应。为了校准系统，测量了聚苯乙烯微球的背向散射频率响应，并与理论预测进行了比较。在单个微球的测量背向散射响应与弹性球体的理论预测之间发现了非常好的一致性。还研究了单个 OCI-AML-5 细胞的背向散射响应。结果发现，AML 细胞的背向散射响应最好使用流体球体模型进行建模。讨论了所开发技术的优点、限制和未来应用。
