Before entering into such an arrangement, you should consult legal advice. There are many things to consider in this arrangement. It is important to have a contract that specifies the basis of the reimbursement. Any contract that specifies reimbursement based on either the value or the volume of the referrals could be problematic.
The question indicates that the mobile radiology would be billing for the technical component of the service which means the services would not fall under the in-office ancillary services exception of Stark. Any lease of space must be in writing, for appropriate space only and at fair market value so as not to appear to be an incentive from the lessee to the physician.
You can find a consultant or attorney at FP Assist.