In hospitals, doctors prescribe examinations for patients. Different types of examinations exist, such as "cardiologic test", "echography", "radiology", "scanner", … Every single examination is of only one type.  Not all possible types of examinations are allowed for all hospitals. For example, some hospitals have no permission for executing NMR scans. A hospital can apply for permission for types of examination.
Suppose the hospital wants to improve & monitor the quality of treatments. In order to do so, per type of problem, a treatment plan is defined. A treatment plan lists the advised types of examinations. When a patient comes with a particular problem, the diagnosis is posed by a doctor affiliated to the hospital visited by the patient. The doctor will define an actual treatment based on an existing treatment plan for the identified problem. The actual treatment of the patient can deviate from the standard treatment plan: it can consist of both advised examinations and freely chosen medical actions. Also, examinations are not necessarily at the same hospital: a doctor can send a patient to another hospital if his/her own hospital doesn't have a permission for the desired examination. By registering all this information, the hospital wants to ensure that examinations are only performed according to permissions, and monitor how much actual treatments diverge from advised treatment plans.