Many diodes make light work

Having just posted a feature on Prof. Jan Bjordal and the WALT dosage recommendations (read here), I am thinking about dose and cluster probes.

The advice from them is that the correct energy should be applied, that the whole pathology should be treated and, in some cases, there is a power density limit.

At our training course last weekend, someone asked how our LED cluster probe treatment dosage can be compared with the WALT guidelines which are based on single probe treatments. For example, the guidelines for treating a tennis elbow is one or two points, 4 joules per point, max 100mW/cm2.

With our 69 LED cluster probe, for example, the total power applied seems very high (1390 mW). It delivers 4 joules in less than 3 seconds. But this energy is delivered over a very wide area (28 cm2), not over a single point as in the WALT guidelines.

If we divide the 1390 mW power delivered by the area covered of 28 cm2, we get 50mW/cm2. So each cm2 gets 50mW, in which case 4 Joules is achieved at every square cm in 1min 10 seconds. That seems reasonable at first.

We conducted studies on a pig and on a cadaver and found that at 3 cm and 5 cm deep. our 69 LED cluster has the same power density at depth as our 200mW laser which has a surface power density of 5,000mW/cm2. The study showed that light at 50mW/cm2 from the LEDs on the surface scatters and then accumulates at depth to achieve the same density as our single 200mW laser. A 200mW laser delivers 4 joules in 20 seconds but with its surface power density of 5,000mW/cm2, it is considered too strong for treating a tennis elbow (as it exceeds the recommended power density maximum of 100mW/cm2). However, the LED cluster probe has a lower surface power density (so doesn’t exceed the WALT guidelines) but maintains a suitable power density several cm down, to deeper the target tissues.

I think that cluster probes achieve the best of both worlds, they have a lower surface density light than most lasers and yet the same subcutaneous density at depth and over a larger area too, so the whole pathology gets a more even treatment.

I would love you to leave me some feedback. If you use our LED clusters what is your clinical experience? and if you are a physicist what formulas might explain this?

I’m thinking that many diodes make light work, better.

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