Liquid nitrogen and BCCs
Liquid nitrogen - now that’s really cold stuff!!! I’ve written a post on dry ice, which is frozen carbon dioxide. It sublimes from solid straight to gas at -78.5 °C. That’s pretty cold, and is why you don’t touch it for more than a second or two (because extreme cold burns you). Nitrogen gas, on the other hand, doesn’t deposit straight to solid (deposition is the opposite of sublimation - these are the two processes of changing between solid and gas without bothering to go through liquid phase). Instead, it exists quite happily as a liquid, provided the temperature is cold enough. What would be cold enough? Try -195.8 °C!!! Yep, that’s the boiling temperature of liquid nitrogen. Keep the temperature lower than this and liquid nitrogen stays, well, liquid.
But what good is it? Oh, all sorts of good. From freezing and transport of food products, to cryopreservation of biological samples, to coolant for superconductors, to fun science experiments like making liquid nitrogen ice cream or freezing flowers and then watching them shatter when tapped onto a hard surface.
It’s also good for burning off things like BCCs, basal cell carcinomas. These are non-melanoma skin cancers, and account for about 75 % of all skin cancers. Sun exposure is by far the most important factor in the development of BCCs. This excessive sun exposure could have actually occurred many years before the BCC develops. Those who are at a greater risk of developing a BCC include people with fair skin, people with a strong family history of BCC and those with a Celtic background.
Well that’s me, not me, and a little bit me. So I guess I have a 50 % chance of developing BCCs? Hmm, I already have (sigh). On Monday I was at the doctor getting five BCCs burnt off with liquid nitrogen. Basically, because it is so cold, the ‘burn’ is due to extreme frostbite. A blister results, turns into a scab, and after a couple of weeks falls away, taking the previous BCC with it. After this is all said and done a scar may result, or a loss of pigmentation. But these are nothing compared to having skin cancer, right???
A biopsy of particularly bad-looking BCCs may be taken, just to confirm its nature and ensure it is a BCC and not a melanoma. Yep, I had a chunk carved out of my forehead to send off to the lab to be analysed. I expect it to come back as BCC. So does my doctor, but it’s always best to be sure. [Update, it was.]
So, moral of the story? A) Use sunscreen!!! It’s been a good lesson for my munchkins, to drill home the importance of sunscreen. And B) If you develop a skin spot that is flaky, sometimes bleeds, and doesn’t heal, go and get it checked out. BCCs are skin cancers, but they’re the least dangerous of skin cancers and quite easily taken care of.