Nuclear perfusionist question?

Hi i was wondering what a Nuclear perfusion ist is? My brother was telling me about it and i tryed to research it on google but everything came up as "Cardiac Perfusionist". Is that another name for it? Well my question is is how much do they get paid and how do you become one and how long do you have to go to school to be one? Another question is can you tell me that daily job of them?? Thankyou!