Reviews and News on Ultrasound Machines

Imaging is not the only medical application for ultrasound. There is a new application that is growing in importance the medical science. Imaging ultrasounds are fairly high intensity, but the changes in that intensity are stable over time.

But if you take the same ultrasound waves, lower the overall intensity, while rapidly changing the intensity from one setting to another over time, you get an entirely different effect. These waves are called High Intensity Focused Ultrasound or HIFU. This heats and destroys pathogenic tissue rapidly. It is a very precise technique. Its precision is due to the ability of the sound waves to be focused to small widths and diameters. It can be directed by several means, but the overall modality remains the same.

Sound waves carry energy. As a sound wave passes through tissue, it generates heat. In a diagnostic ultrasound, this heat is not the goal and great pains are taken to minimize it. In HIFU, the rapid changes between frequencies make much more heat, not unlike the heat generated when you bend a piece of wire back and forth to break it. Once hot enough, the tissue becomes thermally coagulated, rendering it inactive.

It is interesting to note that if this heating is pushed too far, bubbles will be produced. This is called cavitation. These bubbles will grow larger and ultimately implode. This would increase the cell death, but it is an unpredictable process and is not desirable. There is some investigation to see if this can be harnessed, especially with the need to destroy relatively large masses of tissue, but that lies in the future.

The temperatures within the targeted tissue can rise to between sixty-five and eighty-five degrees centigrade, destroying the tissue. This can easily be combined with other treatment modalities for better long term outcomes. Overall, this treatment is valuable because it is noninvasive, generally painless, and highly controlled. It is a valuable new tool in the medical arsenal.