Ultrasound is most commonly known for diagnostic imaging and image-guided interventions, but there is also the potential to harness its power for therapeutic benefits. The use of ultrasound as a therapy is growing, with more than 1,900 active clinical investigations underway. There are also avenues to get insurance reimbursement for the treatment of certain ailments with ultrasound therapy, including bone metastases, essential tremor, and prostate.
In order to help guide physicians that may become involved in the use of ultrasound therapies, the Bioeffects Committee of the American Institute of Ultrasound in Medicine (AIUM) has issued new and updated statements on the AIUM website. These statements help to identify what to consider when using ultrasound therapies, including what happens to the targeted tissue and safety. Some highlights from these statements include:
- Although safe when used properly for imaging, ultrasound can cause biological effects associated with therapeutic benefits when administered at sufficient exposure levels. Ultrasound therapeutic biological effects occur through two known mechanisms: thermal and mechanical. Thermal effects occur as the result of absorption of ultrasound waves within tissue, resulting in heating. Mechanical effects, such as fluid streaming and radiation force, are initiated by the transfer of energy/momentum from the incident pulse to tissue or nearby biofluids. Indirect mechanical effects can also occur through interaction of the ultrasound pulse with microbubbles such as ultrasound contrast agents. Importantly, thermal and mechanical mechanisms can trigger biological responses that result in desired therapeutic endpoints.
- The type of bioeffects generated by ultrasound depend on many factors, including the ultrasound source, exposure conditions, presence of cavitation nuclei, and tissue type. Different bioeffects will require different amounts of ultrasound, and thermal and mechanical mechanisms can occur simultaneously for some exposure conditions.
- There is the possibility of adverse effects in therapeutic ultrasound for targeted and untargeted tissue. Practitioners using these modalities must be well trained on the safe and effective use of therapeutic devices, knowledgeable about potential adverse events, aware of contraindications, and diligent in performing safe procedures. Image guidance should be used to ensure accurate targeting and dosing to maximize the outcomes for patients.
The statements issued by the AIUM’s Bioeffects Committee are intended as baseline considerations when a new therapy device is being put into practice. As ultrasound therapies continue to be adopted into clinical use, the Bioeffects Committee will continue to monitor outcomes in order to inform and educate the community.
Interested in learning more about the bioeffects of ultrasound? Check out the following Official Statements from the American Institute of Ultrasound in Medicine (AIUM):