mphalak,
To restrict rights to only a scan based role is not possible depending on what type of scan you are referring to. For a nodes scan salanting is correct that is part of the Node Management and Admin roles. If you are referring to NCM and IPAM you can select the proper role for those and apply it to a AD you add into SolarWinds. Hope this helps. you can absolutely vote the feature up so they can see more interest.
Hope that helps,
Adam Stephen
Loop 1 Systems
Remote Engineer Level 2
www.loop1systems.com