What is a CT colonography? (Also known as CT colonoscopy, virtual colonography or virtual colonoscopy). A computed tomography colonography (CTC),…Read more
This is the most simple, cost-effective and readily accessible imaging technique available. It provides excellent imaging details of bones, joints and areas of the body where there is substantial soft tissue differences in X-ray absorption; for example, in the thorax where there is marked X-ray differences between bone, lungs and soft tissues.
The most common indications for X-rays are:
A signed request from a referring clinician with appropriate and relevant clinical details.
None. A plain X-ray is a low-dose examination that is cheap and readily available. The small risk must be weighed up against the benefit (see Adverse effects below).
Pregnancy or weight of patient (X-ray tables have weight limits).
No short-term effects. Generally speaking, the benefit of the X-ray procedure is far more important than the small estimated risk (see InsideRadiology: Radiation risk of medical imaging for adults and children). At the dose levels that are utilised in diagnostic radiography, there is little or no evidence of health effects (ARPANSA 2008).
According to ARPANSA (2008) “There is good epidemiological evidence – especially from studies of the survivors of the atomic bombings – that, for several types of cancer, the risk increases roughly linearly with dose”. At low-dose levels (like that in diagnostic radiography), the risk is cancer or heritable mutations, and no such risk has yet been demonstrated in Japanese bomb survivors who received radiation doses comparable to those delivered by plain X-rays or radiographs. There have been no large-scale longitudinal studies of people exposed to diagnostic X-rays that would allow an accurate assessment of risk to be made.
For most plain radiographs/X-rays, the radiation dose is no more than the ionising radiation from the normal environmental background over a period of 1 year. The dose is considerably higher for some CT scans, angiography and some fluoroscopy procedures. However, the minimal risk of exposure to any type of medical ionising radiation needs to be weighed against the potential gain from the diagnostic information provided by the X-ray.
(For further information see InsideRadiology: Radiation risk of medical imaging for adults and children).
Ultrasound and MRI do not utilise radiation, and therefore might be considered as alternatives if diagnostically appropriate. Radiologists have expert knowledge of which imaging test is best suited to answer a clinical question. If you are unsure which is the most appropriate test, then please contact your local radiologist. For example, an ultrasound might be a better test than an X-ray to locate a non-metallic foreign body in the foot.
A radiologist should be consulted for more information.
Page last modified on 31/8/2017.
RANZCR® is not aware that any person intends to act or rely upon the opinions, advices or information contained in this publication or of the manner in which it might be possible to do so. It issues no invitation to any person to act or rely upon such opinions, advices or information or any of them and it accepts no responsibility for any of them.
RANZCR® intends by this statement to exclude liability for any such opinions, advices or information. The content of this publication is not intended as a substitute for medical advice. It is designed to support, not replace, the relationship that exists between a patient and his/her doctor. Some of the tests and procedures included in this publication may not be available at all radiology providers.
RANZCR® recommends that any specific questions regarding any procedure be discussed with a person's family doctor or medical specialist. Whilst every effort is made to ensure the accuracy of the information contained in this publication, RANZCR®, its Board, officers and employees assume no responsibility for its content, use, or interpretation. Each person should rely on their own inquires before making decisions that touch their own interests.