The request · Having a scan
The referral
No imaging examination starts with the person having it. It starts with a written request from a clinician, and in the UK that request has a legal weight.
An imaging request in the United Kingdom is not an informal note passed between clinicians. It is a regulated act, defined by IR(ME)R 2017, the Ionising Radiation (Medical Exposure) Regulations that set out who may request an examination, who may accept it and who may carry it out. This page follows the administrative and legal chain of a referral, from the moment a request is written to the moment the result returns to the person who asked for it.
Who is allowed to request an examination?
Under the definition given in regulation 2 of IR(ME)R 2017, legislation published on legislation.gov.uk, a referrer is a registered health care professional who is entitled in accordance with the employer's procedures to refer individuals for exposure to a practitioner. Two conditions therefore apply at once: professional registration, and entitlement granted locally. The employer must hold a written procedure identifying the individuals entitled to act as referrer, practitioner or operator within a specified scope of practice, a requirement set out in Schedule 2, paragraph 1(b). In other words, the question of who can request which examination is fixed in writing by each employer, within the framework of the Regulations. A page such as who does what helps map how these roles sit alongside each other in a typical imaging department.
What must the referral letter contain?
Regulation 10(5) is precise about the content of a request. The referrer must supply the practitioner with sufficient medical data, such as previous diagnostic information or medical records, relevant to the exposure requested, to enable the practitioner to decide whether there is a sufficient net benefit as required by regulation 11(1)(b). The letter is therefore not a bare test name. It carries the clinical material on which the justification decision will rest.
Why a referral is not an automatic order
Regulation 10(2) states that the practitioner is responsible for the justification of an exposure. A request that arrives in the department is weighed, not executed blindly. Under regulation 11, the practitioner must take account of any data supplied by the referrer pursuant to regulation 10(5) and must consider such data in order to avoid unnecessary exposure. The stated aim is the avoidance of the redundant examination, an imaging study that repeats information already available. If the request is justified, the practical side moves to the operator, who under regulation 10(1) is responsible for each practical aspect carried out, as well as for any authorisation given under regulation 11(5). Both the practitioner and the operator must comply with the employer's procedures, under regulation 10(4).
What happens during and after the exposure?
The operator handles the practical aspects of the examination, which may include the administration of contrast agents where the protocol calls for them. Before the exposure, Schedule 2, paragraph 1(i) requires an employer's procedure providing that, wherever practicable, the individual to be exposed or their representative is given adequate information relating to the benefits and risks associated with the radiation dose from the exposure.
Afterwards, the report is itself a regulatory obligation. Schedule 2, paragraph 1(j) requires a procedure for the carrying out and recording of an evaluation for each exposure, including, where appropriate, factors relevant to patient dose. The radiologist's report is the usual form this recorded evaluation takes. The Royal College of Radiologists describes clinical radiologists as specialist doctors trained to read and interpret medical images, using a wide range of imaging techniques including X-ray, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and molecular imaging. Finally, the result travels back to the person who requested it. For ultrasound, the NHS page updated on 25 February 2025 states that the doctor who referred the patient receives the findings, and that a follow-up appointment may be needed to discuss them.
When the chain breaks: what the regulator records
The Care Quality Commission publishes an annual report on incidents notified under IR(ME)R. For the period from 1 April 2020 to 31 March 2021, in a page updated on 10 August 2022, the CQC states that referrer errors overall accounted for the highest origin of incidents reported, and that the highest number of notifications came from computed tomography (CT). The most frequent error in diagnostic imaging remained an examination intended for another patient: over the period, the CQC received notifications concerning 85 patients referred in error for an imaging examination, and 33 cases where the operator did not correctly identify the patient. Where an incident does occur, Schedule 2, paragraph 1(l) requires a procedure ensuring that the referrer, the practitioner and the individual exposed or their representative are informed of the occurrence of any relevant clinically significant unintended or accidental exposure, and of the outcome of the analysis of this exposure.
| Stage | Responsible role | Regulatory basis |
|---|---|---|
| Request for an examination | Referrer, a registered health care professional entitled by the employer's written procedures | Regulation 2 and Schedule 2, para 1(b) |
| Supply of sufficient medical data | Referrer | Regulation 10(5) |
| Justification of the exposure | Practitioner | Regulations 10(2) and 11 |
| Practical aspects and authorisation | Operator | Regulation 10(1) and 11(5) |
| Recorded clinical evaluation | Employer's procedure, usually delivered as the radiologist's report | Schedule 2, para 1(j) |
When national guidance frames the choice of examination
The choice of examination can also be shaped by national recommendations rather than local preference alone. NICE guidance NG232, Head injury: assessment and early management, published on 18 May 2023, states that the current primary investigation of choice for detecting an acute clinically important traumatic brain injury is CT imaging of the head, and that MRI scanning is not used as the primary investigation for safety, logistic and resource reasons. The same guidance says that plain X-rays of the skull are not used to diagnose important traumatic brain injury before a discussion with a neuroscience unit. For patients aged 16 and over, recommendation 1.5.8 sets a clinical timeframe, with a CT head scan within 1 hour of the identification of certain risk factors, including a GCS of 12 or less at admission, a GCS below 15 at 2 hours, suspected open or depressed skull fracture, signs of basal skull fracture, post-traumatic seizure, focal neurological deficit or more than one episode of vomiting. Recommendation 1.5.7 recalls the dose principle: every effort is made to minimise radiation dose during imaging of the head and cervical spine while ensuring image quality and coverage are sufficient for an adequate diagnostic study.
Checked against the source
- A referrer must be a registered health care professional entitled under the employer's written procedures to refer individuals for exposure to a practitioner (IR(ME)R 2017, regulation 2, legislation.gov.uk).
- Over 1 April 2020 to 31 March 2021, the CQC received notifications concerning 85 patients referred in error for an imaging examination and 33 cases of incorrect patient identification by the operator (CQC IR(ME)R annual report 2020/21, page updated 10 August 2022).
- NICE NG232, published 18 May 2023, names CT imaging of the head as the primary investigation of choice for acute clinically important traumatic brain injury (NICE, recommendation 1.5.1).
- The employer must hold a procedure for the carrying out and recording of an evaluation for each exposure, including factors relevant to patient dose where appropriate (IR(ME)R 2017, Schedule 2, para 1(j)).
The line between the two
The referral and the justification are two distinct steps. The referral is the written request, containing sufficient medical data under regulation 10(5). Justification is the separate decision, taken by the practitioner under regulations 10(2) and 11, that the exposure carries a sufficient net benefit. A request that satisfies every formal requirement can still be declined at the justification stage if the data point to an unnecessary or redundant exposure.
The practitioner and the operator are also distinct roles. The practitioner is responsible for justifying the exposure; the operator is responsible for each practical aspect carried out, and for any authorisation given under regulation 11(5), under regulation 10(1). In some departments the same individual holds both roles, but the responsibilities remain separate in law, and both must comply with the employer's procedures under regulation 10(4).