 This would usually be the dentist in a dental practice.IRMER18 defines a practitioner as a registered medical, dental or other healthcare practitioner who is entitled according to the legal person’s procedures to take responsibility for an individual medical exposure i.e responsible to provide the justification for the X-ray.IRMER18 defines an operator as a registered medical, dental or other healthcare practitioner who is entitled according to the legal person’s procedures to carry out the practical aspects associated with radiographic examination, from patient identification, the X-ray process, to clinical evaluation of the radiographs.