Does it support DICOM as input files?

I was provided MRI DICOM files a month ago via the radiology office's used SaaS platform, Sectra PatientPortal.

After the MRI session I was given a login code. Back home, I could use that code on the Sectra PatientPortal.

It provides a very basic DICOM image web viewer (contrast/dynamic range modification and slice scrolling, four windows), albeit 2D only, and download of the DICOM files as well as PNG exports.

I am looking for a web-based or Linux-based FLOSS DICOM viewer, but couldn't find any professional program so far.