Introduction to Sonodynamic Therapy (SDT)

Dr Ghassan Hamad
Sep 18
3 min read

Updated: Oct 3

The cellular effects of Sonodynamic Therapy

Sonodynamic Therapy (SDT) is a non-invasive technique that combines the use of low-intensity ultrasound with special naturally occurring compounds called sonosensitizers. When activated by sound waves, these compounds can produce useful biological effects at a targeted site.

SDT draws inspiration from Photodynamic Therapy (PDT) – a technique where light activates compounds at the skin surface. Unlike light, ultrasound waves penetrate much deeper, allowing SDT to be used for tissues below the surface. SDT is still considered an emerging, experimental therapy, with ongoing research in Europe and Japan exploring its potential benefits.

What Conditions Can Respond to SDT?

There is a lot of preclinical research and human case studies about the use of STD in cancer supportive care. This is one of the real-life case studies presented in a conference: https://www.saisei-mirai.or.jp/gan/pdf/20131207-presentation-case-report-breast-cancer-patient-gcmaf-sonodynamic-therapy.pdf
There is also some clinical work done on resistant infections such as Lym, mycobacteria and biofilms resistant to conventional therapy. This article gives more details about the use of SDT in resistant bacterial infections: https://pmc.ncbi.nlm.nih.gov/articles/PMC10542942/#:~:text=Abstract,tool%20for%20combating%20bacterial%20infection.

How SDT Works

A sonosensitizer (such as a porphyrin-based compound) is taken orally or intravenously, allowing it to circulate through the body.
Over time, it accumulates in the target tissue.
Low-intensity ultrasound (typically 1 MHz or less) is then applied externally.
The combined effect triggers reactions inside the targeted cells — thought to include the release of reactive oxygen species and trigger dendritis cells and macrophages (reference).

Individually, the sonosensitizer and ultrasound are safe and largely inactive, but together they can enhance cellular responses and influence the tissue microenvironment.

Potential Benefits of SDT

Non-invasive – SDT is delivered via externally applied ultrasound and oral compounds.
Deeper Reach – Ultrasound penetrates further into tissue compared to light, making it suitable for areas not accessible to photodynamic therapy.
Selective Action – Sonosensitizers tend to accumulate in target tissues more than in surrounding healthy cells.
Potentially Fewer Side Effects – Because the sensitizer is mostly inactive until ultrasound is applied, it may minimise widespread effects.

Current Limitations and Considerations

Selectivity of Sonosensitizers – Although they accumulate more in target tissue, perfect selectivity has not yet been achieved.
Photosensitivity – Many sonosensitizers can also react to light; patients may need to avoid direct sunlight or use sun protection for 48 hours after administration.
Blood-Brain Barrier – Delivering sonosensitizers to the brain remains difficult; SDT for brain conditions is still largely experimental.

Conditions We Can Support with SDT

At Leicester Ozone Clinic, we can offer SDT only after careful assessment. We focus on areas considered safer for ultrasound activation, such as some superficial or deeper soft-tissue lesions. However we make no medical claims about the effecacy. However we ensure that what we use is completely safe and natural.

Examples of where SDT may be considered (subject to clinical review):

Certain soft-tissue or lymphatic lesions
Localised bone or muscle areas
Areas resistant to standard supportive approaches

We do not claim to diagnose, treat, or cure cancer. SDT is provided strictly as an adjunctive or supportive therapy.

Safety Checklist

Before undergoing SDT, we assess:

Any allergy or sensitivity to 5-ALA, porphyrins, or other sonosensitising agents
Any medication or herbal remedies known to cause light/photosensitivity
Any history of porphyria or reaction to porphyrin-based drugs
Pregnancy or breastfeeding status
Severe chronic lung or other health conditions
Current use of oral antioxidant supplements (vitamins E, N-acetylcysteine, glutathione)

What to Expect During an SDT Session

If SDT is suitable, you’ll be given an oral sonosensitizing agent (for example 5-ALA at 10–20 mg/kg) to take approximately 6-30 hours before your appointment.
On the day, low-intensity ultrasound will be applied to the target area for approximately 5–15 minutes per lesion.
Protective measures will be explained (such as light precautions after treatment).