A chest X-ray is also more accurately known as a chest radiograph or a chest film. Your doctor will likely just write the letters CXR on the request form.
What is a chest X-ray?
A chest X-ray is the most frequently performed radiological examination. Images are created of the heart, lungs, bones and vessels of the chest. As with all other X-ray examinations, a beam of ionising radiation is projected through the body in order to capture an image on special radiographic film placed on the opposite side of the patient. Newer digital X-ray machines have done away with film and the image is captured on electronic "flat panel detectors".
What are the common uses of a chest X-ray
A chest X-ray is an extremely common examination and there are innumerable indications. It is most frequently used in the investigation of respiratory symptoms such as shortness of breath, wheezing and coughing or after injuries to the chest. Chest X-rays are often part of medical screening procedures and may be requested without any symptoms being present. Common diseases that are detected and followed up using a chest X-ray are: pneumonia, emphysema, lung cancer, aortic aneurysms and heart failure.
How should I prepare?
No special preparation is required. You will usually be given a hospital gown to wear and be asked to remove any clothing and jewellery that may interfere with the X-ray beam.
How is the procedure performed?
Standard chest X-rays involve taking two views while standing, one from the back and from the side. The chest is held against the film holder and the beam is projected from behind or from the side depending on the view. The radiographer will ask you to place your hands on your hips and hold a deep breath while the X-ray is taken. It is a completely painless procedure and you will not be at all aware of the film being taken apart from the beep from the X-ray machine.
The film is then developed which should not take longer than 10 to 15 minutes. Digital images are available immediately and just need to be printed. Patients that are too ill to be moved can have the X-ray taken while lying in bed. In this case the beam is from the front with the film placed underneath the patient.
What are the risks of a chest X-ray
It is important to be aware that all X-ray examinations use ionising radiation with its associated risks. A chest X-ray however results in an extremely low radiation exposure and the benefit of an appropriately requested chest X-ray greatly outweighs the risks. X-ray examinations should be avoided in pregnancy unless absolutely indicated due to the increased risk of birth defects caused by radiation. Your doctor should discuss the pros and cons or possible other options were you to be pregnant. The foetus can also be shielded from the radiation if a chest X-ray should be absolutely necessary.
What are the limitations of a chest X-ray?
A chest X-ray is a very useful investigation in the hands of a skilled clinician or radiologist and is more than adequate in the vast majority of patients. Despite this, it gives poor detail of the soft tissues and vessels in the chest and further investigations may be necessary depending on the information required. CT scans provide very high quality images of all structures in the chest at the expense of high radiation doses and higher cost. Echocardiography and MRI is sometimes used to further investigate the heart. Although ionising radiation is not used in these modalities they are time consuming and in the case of MRI very expensive.