In today's episode of Lasers In Skin, your favourite laser-loving duo, Lisa and Mike, tackle some of the most burning (but not literally!) questions from listeners about laser technology. From dialling in the perfect calibration to decoding the mysteries of fluence and spot size, they break it all down with their signature mix of wit and wisdom. You'll also hear about the best wavelengths for zapping melanin and targeting haemoglobin like a pro. KEY TAKEAWAYS The numbers displayed on laser machines, such as millijoules, often do not accurately represent the actual energy output. Proper calibration using a meter is essential to determine the true energy and fluence delivered to the skin. Changing the spot size of a laser significantly affects the fluence (energy density) delivered to the skin. A larger spot size decreases fluence, which can impact treatment effectiveness, especially for hair removal and vascular treatments. When comparing laser machines, it's crucial to consider power density (power delivered per unit area) rather than just the total power output. Two machines with the same power density can deliver similar treatment results, regardless of their total wattage. Different wavelengths are used to target specific chromophores in the skin. For hair removal, red and infrared wavelengths are preferred due to their deeper penetration, while green and yellow wavelengths are effective for treating blood vessels. Higher fluence levels generally lead to fewer treatment sessions required for effective results. However, the choice of wavelength also affects the necessary fluence, as lower wavelengths can deliver more energy to the target without damaging surrounding tissues. BEST MOMENTS "The reality is that those numbers on a lot of these machines are just what I call scale numbers. They don't refer to the actual energy or power or anything that's coming out of the machine." "If you're using like a 1064 nanometers, because that particular wavelength is the most benign wavelength in the skin. Right. It doesn't do an awful lot of damage." "If you go from say, say that with a lens the spot size is say five millimetres, right, and you swap over, you put on a glass tip and it's now 10 millimetres. That's doubling the diameter, right?" "If you're treating hair, the target that absorbs the light is the melanin. The targets we're trying to kill are the stem cells. But the stem cells don't have a chromophore that we can target." "If you're using huge big spots like 24mm, that's pretty massive, right? Then I would imagine that the maximum fluence you'll get in that spot is fairly low." ABOUT THE HOSTS Mike began his career in medical lasers in 1986 with a physics degree and a post-grad in bioengineering. He helped develop the scar-free removal of tattoos using a Q-Switched Ruby Laser in Glasgow, and the world's first IPL system. Known well in the industry for his hard truths, no BS attitude and logical answers. As the author of three books, articles for medical journals, a well read blog, a Laser Protection Advisor and contributor to the BMLA, Mike is the Laser Guru. Lisa's claim to laser fame is being Mike's daughter. Growing up with lasers and never avoiding a physics lesson from her Dad, it was natural to enter the industry. Leaving a corporate career with a baby to jump into self employed life came with challenges. Despite that Lisa has been well recognised for her teaching style, practical tips, bringing the compassion to the science, and laser mentoring. Instagram: @dermalase_lasertraining https://mikemurphyblog.com https://www.dermalasetraining.com This Podcast has been brought to you by Disruptive Media. https://disruptivemedia.co.uk/