Cancer from radiation is always chance/risk minimisation thing. In this case, the risks are so low as to be practically non-existent. Think walking outside and getting hit by a flying car, sent flying by an exploding petrol station that got hit by lightening multiple times.
I’d go LCD personally. It’s generally going to be nicer to have higher resolutions when you’re doing studies. Just don’t play a ton of dps characters where you study, and you should be more or less fine.
No matter what you pick it will be worse than your home computer, so just focus on what works best for studies, not for gaming.