Can Sound Waves Kill Cancer Cells? (Post #20)

Welcome back to the blog! Today we will be discussing another potential cancer therapy, ultrasound!

When I think of the word ultrasound, I usually correlate it to pregnancy appointments. Doctors use ultrasounds to obtain sonograms, which are like scans of a person's internal body structure. They can be taken on most soft tissues and fluid-filled organs. In pregnant women, they show an image of the developing fetus. This helps doctors track the baby's development.

For reference, here's an example image of a sonogram:

Before understanding how sonograms may help treat cancer, let's first look at how sonograms work: (you'll need to remember a few physics basics for this!)

• ultrasound technology uses sound waves

• when a physician places an ultrasound probe (transducer probe) on skin and turns it on, electric current starts

• this electric current hits crystals inside the transducer probe

  • the crystals vibrate after being hit and create high-frequency sound waves

  • due to their high frequency, these sound waves cannot be heard by humans

• the sound waves travel through skin into the patient's body

• after they hit tissue in the body, some of them bounce back

• the bounced waves come back to the probe

  • the probe detects these reflected waves as an echo

• the echoes again hit the crystals inside the trasducer probe

• these vibrations in the crystal convert the sound into an electrical signal

• the attached computer measures the time taken for echoes to return and compares speed to create a live image of the internal tissue of a patient

  • fast echoes: shallow tissues

  • slow echoes: deep tissues

  • strength of signal inidicates how dense the tissue is (tissue is denser than fluid)

But how does this imaging technology have any effect on cancer cells and tumors?

Well, in July of this year (2026), research at the Indian Institute of Science found that low-frequency ultrasound has the ability to damage oral cancer cells. Not only that, but they found that these ultrasound waves were selectively damaging, meaning they harmed only cancer cells, leaving healthy cells unharmed.

While this idea is still in the research stage, it raises an interesting question: can sound waves be used as treatment for cancer?

Let's take a closer look at how ultrasound affects cancer cells. We learned that scientists can use reflected sound waves to create an image, but what we didn't know is that they can also use these waves to produce physical forces inside the body.

When these sound waves enter the body, they are not simply reflected. A fraction of these waves is also absorbed by tissue, creating a physical force on tissue. This force, if strong enough, can exert enough pressure on cancer cells to 'break' them. Through research, scientists found that the force is best exerted upon cells by low-frequency ultrasound waves. These waves apply the best mechanical pressure on cells, causing damage to the cell membrane and eventually cell death.

But then why are healthy cells not affected? Well, that's because healthy cells have different physical properties than cancer cells. One of those differences in property is how they respond to mechanical pressure. When force is applied to cancerous cells, they stretch more than healthy cells. This stretching causes an extra influx of calcium ions (Ca 2+). The influx weakens the mitochondria, which we know produce energy (ATP) for the cells (Look at Post #18 for background information). Eventually, the cancer cell does not have enough energy to function and dies. So, cancer cells are more susceptible to ultrasound waves than healthy cells.

While this technology has great potential, it is still in the early stages of being researched. It is not yet strong enough to completely replace surgery as a treatment. Researchers are also investigating whether combining ultrasound therapy with other therapies like radiation/immunotherapy may be effective.

Thanks for reading this week's post! I hope you learned something new. See you again for the next post!

Information Citations:

“Indian Institute of Science.” Iisc.Ac.In, 2025, https://www.iisc.ac.in/events/using-ultrasound-to-attack-oral-cancer-cells/.

ecancer. “Scientists Use Ultrasound to Soften and Treat Cancer Tumors Without Damaging Healthy Tissue.” Ecancer.Org, ecancer, 16 Dec. 2025, https://ecancer.org/en/news/27504-scientists-use-ultrasound-to-soften-and-treat-cancer-tumors-without-damaging-healthy-tissue.

Image Citations:

UT Southwestern Medical Center. Ultrasounds Tell Doctors about Your Baby’s Health, but Some Terms on the Images Can Be Alarming without Context. https://utswmed.org/medblog/pregnancy-ultrasound-scary/. Accessed 2 Aug. 2026.