Clearance check devices, systems, and methods that can be used to indicate whether a proposed treatment plan will cause a collision between a patient/couch and a medical device, such as a linac, are described herein. Some devices and/or systems include an adjustable clearance member to account for the rotation of the medical device and a rotatable frame segment to account for the rotation of the patient or couch. Others include a frame segment that has an inner surface defining an arc that has a radius that is substantially equal to or less than an orbital radius of a centermost portion of a medical equipment component. Still others are disclosed.
