you use the right light wavelength the right light color that penetration is extremely long it's like a meter or so right all right so let's take a step back and ask yourself the question what does it take to get a good image if you we all know how x-ray chest x-ray works right chest x-ray works so well because x-ray does not scatter so much in tissue you get what's called ballistic light ballistic photons in x-ray regime so that's gonna cast a shadow directly for you and you can see that the bones and certain structures if you mimic x-ray