 One of the things that was learned is that if you use special fluorescence or discrete or a special light, you can see on the tumor what it does fluoresce, correct? And then you can come and cut. So we have all that safety. So people start saying, well, what it was if we use photons, what if we use light, correct? And then people start using light to activate ALA to eventually have protoporphine produced by our OSS. That has been done for a long time too, and there is evidence. If you put a light into a GBM patient that have received ALA, and you put the lasers inside the brain and the people that have done that, you see an activity. You see an activation of the 5-ALA, the whole process, and destruction of the tumor. And we have some of that data. But the beauty of our founder, correct, who has been working on photodynamic therapy for over 20 years, is that he says, you know what? You can create light using sound. So the same principle, then using ultrasound waves can activate this micromoment of light with the frequency of the ultrasound externally. So you don't have to put a laser through your brain or anywhere that you want to test this. You just put the ultrasound and get the same effect. That's the beauty. So photodynamic therapy eventually becomes sonodynamic therapy. So instead of using a source of light, we use sound to activate the effect on the 5-ALA and the cells.