today there are cat scans and mri s. i worry about them. i worry about the cat scans beatcause there s a tremendous amount odf radiation. i don t know if i ve told you before, but a cat scan of the lung has as much radiation as something like 300 or 400 chest x-rays. now, they may become necessary. i had one don we on a patient o mine who was aot smoker, totall asymptomatic. i did a routine one and we picked up a cancer of the lung. and saved his life by removing it. so these things are very important. but they should only be done when necessary. now, with regard to the m.r.i. which is magnetic resonanceag imaging. in order to see the picture, they have to inject a chemal. it s a chemical that has it s potentially dangerous if you have any kind of kidney problem and sometimes liver problem.