The security options of using an anti virus (but make it an internet security) and Malwarebytes is good.
Also, you can force all your employees to scan the devices before starting any work.
People need things done in an instant. This is a major problem everywhere.
First things first,
The question you posed is running in the minds of people all around the world since the invention of virus family .
Sorry, no offense meant.
Here goes my idea, think whatever you think of it.
Set up a separate system first, With the intent of security purposes.
Have an antivirus (use some good ones and Paid ones, though I would suggest Kaspersky/ Nod32; the choice is yours. But whatever please do not go for Avast/AVG.)
Also, have Malwarebytes (Premium version please, we need real time monitoring which is a premium feature only).
The system should be having internet connection but no one should be using emails/browsing. People can be stupid many a number of times.
Scan the media on this system then move on to your working systems.
Make a mandatory rule for scanning the external media before using.
Why did I suggest an entirely new system for scanning?
The video editing/ Photo editing software use fairly high system resources. Security Software may at times clash with them being the reason.
You can request them to give the data (initial data required) in form of DVD's/CDs.
Also, you can give their final input in the same format. I mean applying a no USB policy.
(Which these days is a very difficult process, believe me, I experienced it myself).