Huang Chih-Chung, Ameri Hossein, Deboer Charles, Rowley Adrian P, Xu Xiaochen, Sun Lei, Wang Shyh-Hau, Humayun Mark S, Shung K Kirk
NIH Resource on Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, California, Los Angeles, CA 90089-1111, USA
Ultrasound Med Biol. 2007 Oct;33(10):1609-16. doi: 10.1016/j.ultrasmedbio.2007.05.002. Epub 2007 Jul 6.
Ultrasonic parameters of sound velocity and frequency-dependent attenuation ranging from 25 to 45 MHz were measured for the purpose of evaluating the hardness of lenses in cataract surgery (phacoemulsification). Measurements were performed with a 35-MHz ultrasonic transducer on porcine lenses in which artificially cataracts were induced. The hardness of the cataractous lens was also evaluated by mechanical measurement of its elastic properties. The results indicated that the ultrasonic attenuation coefficients in normal porcine lenses were approximately 4.49 +/- 0.05 (mean +/- SD) and 6.32 +/- 0.04 dB/mm at 30 and 40 MHz, respectively. The development progression of the cataracts resulted in the attenuation coefficient increasing linearly to 7.36 +/- 0.25 and 11.1 +/- 0.92 dB/mm, respectively, corresponding to an increase of Young's modulus from 2.6 to 101.2 kPa. The sound velocity concomitantly increased from 1639.8 +/- 4.2 to 1735.6 +/- 10.4 m/s. Evaluation of the relationship between the phacoemulsification energy level and ultrasonic parameters in vitro by surgeons revealed that both the attenuation coefficient and sound velocity were linearly correlated with the phacoemulsification energy (r = 0.941 and 0.915, respectively). These results showed that measuring high-frequency ultrasonic parameters provides surgeons with good capability and reproducibility for selecting the optimal energy level for phacoemulsification.
为了评估白内障手术（超声乳化）中晶状体的硬度，测量了25至45MHz范围内的声速和频率依赖性衰减等超声参数。使用35MHz超声换能器对诱发了人工白内障的猪晶状体进行测量。还通过对白内障晶状体弹性特性的机械测量来评估其硬度。结果表明，正常猪晶状体在30和40MHz时的超声衰减系数分别约为4.49±0.05（均值±标准差）和6.32±0.04dB/mm。白内障的发展进程导致衰减系数分别线性增加至7.36±0.25和11.1±0.92dB/mm，对应杨氏模量从2.6kPa增加到101.2kPa。声速随之从1639.8±4.2m/s增加到1735.6±10.4m/s。外科医生在体外评估超声乳化能量水平与超声参数之间的关系发现，衰减系数和声速均与超声乳化能量呈线性相关（r分别为0.941和0.915）。这些结果表明，测量高频超声参数为外科医生选择超声乳化的最佳能量水平提供了良好的能力和可重复性。
