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Benefit and risk of X-ray diagnostics

  • X-ray diagnostics is performed by the doctor when other procedures such as laboratory tests, ultrasound or endoscopy would fail to provide a precise diagnosis.
  • For practical radiation protection purposes it is assumed that each X-ray examination is associated with some, albeit low, radiation risk.
  • An X-ray procedure is only justified if the radiation risk is very low compared with the diagnostic or therapeutic benefit.

right lower leg with plate X-ray imageX-ray image

X-ray diagnostics is performed by the doctor when other procedures such as laboratory tests, ultrasound or endoscopy would fail to provide a precise diagnosis. It often is the procedure that permits or confirms diagnosis or can specify findings in the first place.

The following examples illustrate the importance of X-ray diagnostics:

  • Reliable diagnosis of a bone fracture and check for correct reduction of fracture dislocations.
  • Clarification of a head injury following an accident in cases of suspected intracranial bleedings.
  • Timely diagnosis of narrowed blood vessels, for example narrowed coronary vessels, by means of angiography, thus reducing the risk of myocardial infarction by an appropriate intervention, such as dilation of the constricted vessel, under fluoroscopic control.
  • Early detection of breast cancer for women participating in a mammography screening programme.

Radiation risk

In most cases, X-ray examinations involve very low doses. For the low dose range, however, no reliable information on the radiation risk can be verified. For practical radiation protection purposes, it is assumed as a precaution that every X-ray examination involves a certain, albeit low, radiation risk. That is because in radiation protection it is conservatively assumed that there is no threshold dose below which the radiation risk is zero. Also, a proportional relationship between dose and cancer risk is generally presumed (so-called linear non-threshold (LNT) hypothesis).

Radiation risk and age

In radiation risk assessment, it must also be taken into account that the majority of all X-ray examinations are carried out in elderly patients. This is especially true for more dose-intensive procedures, such as computer tomography or angiography. Radiation risk is strongly dependent on age, being – at equal dose – lower for an elderly than for a younger person.

Furthermore, severely ill patients receive an above-average number of X-ray examinations. The life expectancy of these patients is usually limited and therefore shorter than the latency period of a radiation-induced cancer.

A group of doctors having a conversation DoctorsDoctors in conversation: Do the benefits outweigh the risks of an X-ray exam? Source: Robert Kneschke/Stock.adobe.com

How to reduce medical radiation exposure

  • Avoid unnecessary X-ray examinations: An X-ray examination is only useful if the result can prevent or confirm a suspected diagnosis, or if it can affect treatment options.
  • Dose optimization: Most types of X-ray examinations are standardized. Each examination is to be optimized in accordance with the principles of radiation protection. As dose limits could reduce the diagnostic benefit, it is currently internationally recommended that no dose limits are to be set for patients undergoing radiological examinations. Nevertheless, physicians are required to carry out each examination in such a way that the radiation exposure for the patient is as low as possible. As a guideline, the Federal Office for Radiation Protection compiles and publishes Diagnostic Reference Levels which should generally not be exceeded in standard examinations in normal weight patients.
  • Justification: An X-ray examination is justified if the patient benefits considerably from the examination and, compared with this, the radiation risk is low. According to the German X-ray ordinance, a thorough benefit risk assessment is to be performed. This justification must be carried out by a specialized physician.
  • Alternative imaging procedures: Every patient should ask why an X-ray examination is necessary and whether or not alternative diagnostic procedures might be applied, for example an ultrasound examination or a magnetic resonance tomography.
  • X-ray record card: The “Röntgenpass” (X-ray record card) is an important tool to avoid unnecessary duplications of X-ray procedures. It also allows reference to previous X-ray images. The BfS recommends that also nuclear medicine examinations are recorded in the Röntgenpass..
State of 2021.10.12

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