File last viewed by? Can I tell?

I am not sure if this is possible or not. My boss creates files on a monthly basis for other dept. heads to view/change. She isn’t sure if these dept. heads are even viewing these files. Is it possible to see who has viewed a particular file? I know who has ACCESS to it but how do I see if they are even viewing it? This file is stored on our server. Can I set something up to show if anyone has viewed the file?