20MHz HFU possess important value in dia gnosis of diseases of small and ductus, such as dilation of duct of breast, dila tion of deferent duct, dilation of duct of steno, penile induration and dermopa thy.

• 对小的病灶及细小管状结构的检查如乳腺导管扩张、输精管扩张、腮腺管扩张、阴茎硬结以及皮肤弥漫性或结节性病灶等检查具有重要价值