Where could we find some guidelines/guidance documents on the subject of data archival requirements?

As the Sponsor, we have received notification from the Medical Imaging Service Provider that they have completed the final data transfer for our study. The Medical Imaging Service Provider has contacted us (Sponsor) regarding our needs for data archival. The Medical Imaging Service Provider can either archive the study images, data and materials, or they can send it all to us (Sponsor) for archiving. Is this data considered "source documents" and as the Sponsor can we accept it?