Radiation Protection Information

Radiation Protection and Ionising Radiation (Medical Exposure) Regulations 2000

Medical professionals who refer patients for imaging examinations have a key role to play in minimising the radiation dose received by members of the public.

They have duties governed by Radiation Protection Legislation.

The radiation doses for most medical exposures are quite small, when considered in relation to the benefit to the patient from improved diagnosis. Exact doses are difficult to quote since these will vary between patients, depending on patient size, and clinical indications.

The Medical Professional must consider the risk / benefit for every radiation exposure they request and be certain that the examination requested has the potential to alter the patient's clinical management. This will ensure that the radiation dose to the patient will be kept as low as reasonably practicable.

To help put these radiation doses into perspective, the table below relates certain examinations to the equivalent background radiation received.


Procedure Typical Effective Dose (mSv) Equivalent number of chest xrays Approximate equivalent period of background radiation
CT Abdomen 10 500 4.5 years
CT Chest 8 400 3.6 years
Barium Enema 7.2 360 3.2 years
Radioisotope Bone Scan 4 200 1.8 years
Barium Meal 2.6 130 15 months
IVU 2.4 120 14 months
CT Head 2.0 100 10 months
Barium Swallow 1.5 75 8 months
Lung Ventilation 0.3 15 7 weeks
Lumbar Spine 1.0 50 5 months
Abdomen 0.7 38 4 months
Pelvis 0.7 35 4 months
Hip 0.4 20 2 months
Skull 0.06 3 9 days
Chest 0.02 1 3 days
Limbs and Joints <0.01 <0.5 <1.5 days


 The IR(ME) Regulations came into force in January 2001 and outline the legal requirements for all those involved in radiographic examinations.

 Below is a summary of the main points. This is not a complete record and medical and Non Medical referrers must ensure that they are familiar with and comply with the full Regulations.

  • A correctly completed Department of Radiology referral must be submitted prior to investigation for every radiological examination. This must be written or completed electronically by the referrer.
  • The patient must be identifiable from the referral. Name, date of birth and hospital number must be present together with the Consultant. It is the responsibility of the referrer to ensure that the correct patient ID is clear on the referral, and that it is for the correct examination, relevant to the patient's condition.
  • The referrer must be identifiable. When making a paper referral it is important that there is a referrer's signature and name written legibly, together with contact number / bleep.
  • It is helpful if the patient's mode of transport to radiology can be selected, and whether that patient needs oxygen
  • It is important that if the patient is barrier nursed or has any special requirements that this is noted on the referral, to enable the radiology department to prevent cross infection and cater for individual needs.
  • Clinical indications and questions must conform to those in the radiology department protocols. If they do not, or there is insufficient information to justify the examination, then it should not be performed.
  • For all females of reproductive age, where the investigation involves irradiating the abdomen (and all nuclear medicine examinations) the date of the last menstrual period must be stated on the referral.
  • If the referral is incompletely or illegibly completed, legally the examination cannot be performed and will be returned to the referrer.
  • The referrer must supply sufficient medical information to enable the practitioner to justify the examination. It is intended that the departmental protocols will assist the referrer to ensure that the patient only receives an exposure of radiation when the result will affect the management of that patient, thus keeping the overall dose to the population as low as reasonably achievable. These Referral and Justification protocols are based on the Royal College of Radiologists Guidelines.
  • The referrer must discuss the examination with the patient to ensure that they understand and can give verbal consent (simple exams) or written consent (complex exams).
  • It is essential that the radiology department are informed if there is any possibility that the patient could be pregnant.   Whilst the majority of low dose diagnostic imaging examinations present very little risk to the fetus, it is essential that the examination is clinically justified and the dose kept to a minimum, consistent with the diagnostic requirements.  High dose procedures should be avoided in pregnant women; however, if such examinations are considered to be clinically justified, the risk is still very low in absolute terms. 

IRMER (2000)

As outlined in IRMER (2000);

  • The referrer must supply the practitioner with sufficient medical data relevant to the medical exposure to enable the practitioner to decide whether the exposure can be justified. The referrer must supply adequate and relevant clinical information to enable the practitioner to justify the exposure.
  • The referrer has a particular responsibility to ensure the completeness and accuracy of data relating to the patient's condition.
  • The relevance of clinical findings as indicators for a medical exposure is also a requirement. Failure to provide such information may result in an inappropriate exposure being performed or an exposure not being performed because of the lack of relevant information.

Xrays - How safe are they?