Mike Murphy's Blog

Many laser and IPL treatments require a significant temperature rise in the target cells, to effectively kill them. We use light energy to induce this temperature rise. But, calculations show that, in some cases, less than 1% of the light energy is actually doing the job we want.

That means that more than 99% of the light energy is essentially ‘wasted’. It generates heat in the epidermis and dermis, but this heat will damage other tissues, rather than the intended targets.

So, COOLING IS KING!

We must cool the skin effectively to minimise any unwanted tissue damage. Many systems have cooling devices built into their handpieces, particularly IPLs. Some of these tips can be very cold, even down at zero degrees Celsius. We can use this to our advantage.

Below is a video I made of my preferred cooling technique….

It is a three stage process:

1. Put some water-based gel onto the skin surface. Apply the cold handpiece tip to the skin to ‘pre-cool’ the upper skin layers, especially the basal layer where many melanosomes live. By cooling these tissues for a second or two, we reduce the chances of them becoming too hot. Use longer pre-cooling times for higher fluences.
2. Apply the light energy.
3. Keep the handpiece tip on the skin surface. The tip is usually very cold so it will suck the excess heat energy out of the skin much more rapidly than the air. I usually keep the tip on the skin for about two to three seconds after the treatment.

By applying this pre- and post-cooling technique we will reduce the risk of unwanted thermal damage in the skin. This method slows down the whole treatment process, but your clients will much prefer it.

Once an area has been treated, apply ice-packs for around ten minutes. This will draw out any residual heat energy.

A major advantage of this technique is that it allows us to use higher fluences – which translates into higher temperatures in the skin. We know that higher fluences result in better treatment outcomes, but only if the adjacent skin is properly protected.

I routinely use 40 J/cm² on the skin for hair and blood vessels, but with 2 to 3 second pre-cooling times. This makes the treatment comfortable. Without the pre-cooling, it would be painful (I know this, from experience!!)

As I said above, we are deliberately trying to induce cellular damage using heat.  But most of the heat is flowing around the dermis, which will damage other cells. The above cooling technique will help to reduce that damage significantly.

Summary

Photo-thermal treatments can generate excellent results, regardless of the technology – but only if the correct energy (fluence) is applied over the correct timescale (pulsewidth). However, this inevitably generates too much heat in the skin, which is not good. Proper cooling techniques will help to minimise tissue damage, while allowing good results to be achievable.

I suggest you try the above technique on yourself. Do three or four shots with zero, 1, 2 and 3 second pre-cooling times. You will feel a big difference between them.

Hope this helps,

Mike.