This is an important question but has not been properly studied clinically (to my knowledge). When my research group first developed the Q-switched ruby laser treatment of tattoos in Canniesburn Hospital, Glasgow, in the early 1980s they established that a minimum four-week period was the optimum time between repeat laser sessions. This became the standard… Continue reading How long should you leave between laser tattoo removal treatments?
Laser-IPL Penetration Depth – a more useful definition
The ‘standard’ definition of penetration depth in skin only considers the incident wavelength and optical properties of the skin. While this may be useful from a physics perspective, it is not particularly useful when considering clinical treatments. A more useful definition must include wavelength, anisotropy, spot diameter and incident fluence. All of these have an… Continue reading Laser-IPL Penetration Depth – a more useful definition
Tattoo removed in just 4 sessions using a QS Nd:YAG at 1064nm
The following is an experiment I carried out to test a theory. A number of experiences had made me think that the time between laser sessions is more important than first thought. My clinical group first developed scar-free laser tattoo removal back in the 1980s in Canniesburn Hospital, Glasgow, Scotland. Back then, we were using… Continue reading Tattoo removed in just 4 sessions using a QS Nd:YAG at 1064nm
Calibrating an IPL device
How do you know what fluence or energy is coming out of your IPL unit? Some devices will have an on-board meter, but many don’t. In that case, you really should get it properly calibrated. You can only do this with an appropriate meter which should be able to measure both the fluence and the… Continue reading Calibrating an IPL device
Laser spot size – how it changes with distance from the target…
Most laser systems have a lens to focus the laser energy down to a sale spot diameter (see figure 1 below). However, in many systems, the focal point (where the spot diameter is the smallest) is outside the handpiece assembly. This has a potentially hazardous effect if not properly understood! The problem with this design… Continue reading Laser spot size – how it changes with distance from the target…
IPL filters
IPL systems typically use a Xenon flash lamp to generate light across a wide range of wavelengths, usually 400 to 1200 nm. To select a ‘useful’ range a filter is applied. These are generally ‘cut off’ filters which stop all wavelengths below a given value, from transmitting through. Hence, a 650 nm will stop all… Continue reading IPL filters
Carbon Facial treatment with a QS Nd:YAG laser
Recently I tried the new ‘carbon facial’ treatment using the 1064nm wavelength of the Q-switched Nd:YAG laser. My wife was keen to try it! I painted a little black carbon ink solution (which I made myself) onto my wife’s face. After about 20 minutes, or so, to allow it to dry, I applied the laser… Continue reading Carbon Facial treatment with a QS Nd:YAG laser
What is ‘energy density’ or ‘fluence’?
Many laser operators are not sure what is meant by energy density or fluence. They should know this as it is fundamental to generating good clinical outcomes. Here’s a video I made explaining how to calculate ED/fluence… You can download a pdf copy of the above here. Hope this clears this topic… Continue reading What is ‘energy density’ or ‘fluence’?
Experiments with India ink and a Q-switched Nd:YAG laser
What happens when India ink absorbs laser energy? I irradiated some dry India ink trapped between two glass slides here (the ink was allowed to dry overnight). I used 5 J/cm^2 with a 1064 nm wavelength. As you can see, the laser energy ‘vapourises’ the ink and leaves voids behind. But, very little ink leaves… Continue reading Experiments with India ink and a Q-switched Nd:YAG laser
Spreading the coronavirus through simple speech…
We spit when we speak! Gross!!!! But we do. We can’t help it. It’s perfectly natural but we cannot see those tiny droplets of saliva in the air – usually. But, if you have a nice, big, powerful, visible laser, then you can see the spit, in flight! Some scientists did exactly this. The video… Continue reading Spreading the coronavirus through simple speech…
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