Ultrasound Machines – Understanding Jargon Like Frequency, Pulsation, Head size, MHz
So, you want to buy an ultrasound therapy machine. You check the internet (of course) and you see a nice picture so you click on it. This is the product description that you find:
Well… that’s about as clear as mud. It might be easy to understand all this medical jargon if you actually are a medical professional of some kind – someone who uses an ultrasound machine on a daily basis; but what about the rest of us? I would like to explain a couple of technical details about ultrasound therapy machines that could really make the difference if you are looking to have a machine at home.
What does frequency have to do with ultrasound machines? Ultrasound machines use ultrasonic waves to treat deep tissue pain and to improve the healing process. The frequency refers to the speed that the sound waves move through your tissues. Frequency is measured in hertz (Hz), which are units that symbolize 1 cycle of a wave (1 compression and 1 rarefaction in this case). In the product description above, the machine offers both 1 MHz (megahertz= 1 million Hz) and 3.3 MHz.
Why do we want to know the frequency? If there is a higher frequency, then there is lower tissue penetration. If there is lower frequency, then there is higher tissue penetration. The machine in the example above offers both a low and high frequency, making the unit more versatile. You might want to use a lower frequency if you are treating a thick section of tissue such as the thighs or the lower back. You would use a higher frequency on joints or near bones because you don’t have to penetrate nearly as deep in those areas.
The second bullet on the product above says “10%, 20%, 50% and continuous duty cycle selections with head warming.” This refers to the pulsing of the ultrasound machine. During an ultrasound treatment, you can have ultrasonic waves permeating your tissue throughout the treatment or in specific time intervals. The continuous option is just what it sounds like- a constant stream of ultrasound waves being emitted from the machine. This is an excellent option for easing muscle spasms or chronic pain. The percentages (10%, 20%, and 50%) refer to the ratio of ultrasonic waves to“down time.” Pulsing is a good option if you are trying to increase blood flow or speed up the healing process. It keeps the tissue from overheating while still easing the pain.
Here’s a chart that shows some other common ratios for pulsed ultrasound treatments:
Something else to consider when looking at ultrasound therapy machines is the head size of the applicator. You may not have thought about it, but the size of the sound head is really important when picking an ultrasound therapy machine! Ultrasound waves move much faster and are much more effective if they move through a material. Therefore, ultrasound therapy machines are designed to work only when the sound head is against skin or a similar medium. If you end up with a big sound head and you are trying to do and ultrasound therapy treatment on your knuckles, it won’t work. The sound head is much too big for the area in which you are trying to apply the therapy! The entire metal head needs to be in contact with skin in order to function. A smaller head size would work well for small joints like these. On the flip side, doing ultrasound therapy on your lower back with a small sound head would take much more time than necessary. The therapy would still work, it would just take forever. If you are treating a large area, then it is important to have a larger sound head that fits the area you are treating.
When looking to buy an ultrasound therapy machine, it’s also important to browse the market and see what’s out there. This article gives the very basics of the machine functions, but there is always more to learn! I encourage you to do more research before you buy an ultrasound machine for home use. Understanding the science behind the treatment can help you use your ultrasound machine effectively and safely. Good luck!