MicroDicom is free for non-commercial use. If you are a medical student, you can use it for free. When you run it for the first time, it will ask you to register MicroDicom. Select the desired option.
I swear by FastStone Image Viewer instead. You might mistake it for a relic from the Windows XP era, but the old-school ...
Here is a list of some free multipage TIFF viewer software and online tools added in this post: BitRecover Tiff Viewer Windows Photo Viewer Universal Viewer Online Document Viewer TIF, TIFF Viewer ...