Iowa Code § 135B.26: Compensation.

The contract between the hospital and doctor in charge of the laboratory or X ray facilities may contain any provision for compensation of each upon which they mutually agree. The contract may create the relationship of employer and employee between the hospital and the radiologist or pathologist. A percentage arrangement or a relationship of employer and employee between the hospital and the radiologist or pathologist is not unprofessional conduct on the part of the doctor or in violation of the statutes of this state upon the part of the hospital.