Using a 27 inch mid 2011 iMac as a monitor for a Windows laptop

Hi

can anyone help out there as I’m getting conflicting messages about whether it can or not?

i have a mid 2011 iMac with a Thunderbolt port and mini display port. I have a Lenovo laptop with a HDMI port and several USB A ports. As my laptop screen is small I was looking to use my Mac as a monitor.

can this be done? If it can is it best to get a thunderbolt to HDMI adaptor or Mini DisplayPort to HDMI adaptor?

any advice?