| 摘要 |
Ultrasound generating methods and apparatus are disclosed for producing controlled, localized hyperthermia in a selected heating zone of human tissue, utilizing at least one ultrasound transducer, preferably driven by sinusoidal excitation signals in a continuous wave or quasi-continuous wave mode to generate ultrasound. The temperature in the heated zone can be controlled by selecting the power, duration and frequency of the ultrasound. The penetration of the ultrasound, and thus the depth and volume of the target zone, can be controlled by selecting the excitation frequencies so to confine the absorption of the ultrasound beam in the target tissue. The invention is particularly useful in inducing controlled collagen shrinkage in corneal tissue to effective thermokeratoplasty (heat induced modification of the shape of the cornea).
|
