Thunder Bay Regional Research Institute and Electrical Engineering, Lakehead University, Thunder Bay, Ontario, Canada.
Ultrasound Med Biol. 2011 Aug;37(8):1230-9. doi: 10.1016/j.ultrasmedbio.2011.05.013. Epub 2011 Jun 16.
Recently, an in vivo real-time ultrasound-based monitoring technique that uses localized harmonic motion (LHM) to detect changes in tissues during focused ultrasound surgery (FUS) has been proposed to control the exposure. This technique can potentially be used as well for targeting imaging. In the present study, we evaluated the potential of using LHM to detect changes in stiffness and the feasibility of using it for imaging purposes in phantoms and in vivo tumor detection. A single-element FUS transducer (80 mm focal length, 100 mm diameter, 1.485 MHz) was used for inducing a localized harmonic motion and a separate ultrasound diagnostic transducer excited by a pulser/receiver (5 kHz PRF, 5 MHz) was used to track motion. The motion was estimated using cross-correlation techniques on the acquired radio-frequency (RF) signal. Silicon phantom studies were performed to determine the size of inclusion that was possible to detect using this technique. Inclusions were discerned from the surroundings as a reduction on LHM amplitude and it was possible to depict inclusions as small as 4 mm. The amplitude of the induced LHM was always lower at the inclusions compared with the one obtained at the surroundings. Ten New Zealand rabbits had VX2 tumors implanted on their thighs and LHM was induced and measured at the tumor region. Tumors (as small as 10 mm in length and 4 mm in width) were discerned from the surroundings as a reduction on LHM amplitude.
最近，提出了一种基于体内实时超声的监测技术，该技术利用局部谐波运动（LHM）来检测聚焦超声手术（FUS）过程中组织的变化，以控制辐射暴露。该技术也有可能用于靶向成像。在本研究中，我们评估了使用 LHM 检测刚度变化的潜力，并评估了其在体模和体内肿瘤检测中用于成像目的的可行性。使用单个元件 FUS 换能器（80 毫米焦距，100 毫米直径，1.485 兆赫）来产生局部谐波运动，使用单独的超声诊断换能器（5 kHz PRF，5 MHz）来跟踪运动。运动使用采集到的射频（RF）信号上的互相关技术来估计。硅体模研究用于确定使用该技术可能检测到的包含物的大小。通过降低 LHM 幅度，可以将包含物与周围环境区分开来，并且可以描绘出小至 4 毫米的包含物。与周围环境相比，在包含物处诱导的 LHM 幅度总是较低。在新西兰白兔的大腿上植入了 VX2 肿瘤，在肿瘤区域诱导并测量了 LHM。通过降低 LHM 幅度，可以将肿瘤（长度小至 10 毫米，宽度小至 4 毫米）与周围环境区分开来。
