Wilmington, Mass.-based ONI Medical Systems, a developer of new magnetic-resonance imaging systems, raised $12.5 million in a third funding round. Ziegler Meditech Equity Partners led the round, joined by private-equity firms Galen Partners and Ivy Capital Partners.

ONI makes “anatomy-specific” MRI systems designed to scan particular parts of the body, such as the legs or arms. Traditional MRIs are huge hollow tubes that scan the patient’s entire body, an experience that requires the individual to lie perfectly still and which can induce claustrophobia.