Chest X-rays are the most commonly taken X-ray images administered in hospitals and clinics today.
Chest X-rays are taken when a patient is suspected of having problems with the lungs, heart, or other chest structures.
Even when there's no sign of illness, chest X-rays are commonly administered during annual physical checkups, prior to employment, prior to getting insurance, prior to surgery, and even for immigration.
In the course of this procedure, radiation is momentarily applied to the chest. The image that is produced results from the X-rays passing through the chest and reaching the film. Structures like bone, which are dense and have a high atomic number, absorb a lot of X-rays, and fewer X-rays reach the film, thus appearing white. Structures like the lungs, which are full of air and have a low atomic number and density, appear black because most X-rays pass through without being absorbed. Heart, muscle, fat, tumor, pneumonia, and fluid absorb fewer X-rays than bone, but absorb more than air, so they appear gray on film.
In the case of lung cancer, tumors absorb more X-ray than the lungs, making them appear as a white mass in the middle of black lungs. With emphysema (or chronic obstructive pulmonary disease) from long-time smoking, the lungs have more air from over-expansion and appear even darker on chest radiography.
Chest radiography can be done to evaluate chest symptoms, such as coughing, coughing up sputum or blood, chest pain, and shortness of breath.
Even when there are no chest symptoms, a chest X-ray might be useful in cases involving injury to the chest, or to evaluate the source of fever, or to ascertain cancer spread.
If abnormalities are found, a serial chest X-ray may be given to observe changes over time.
- Lung cancer
- Chronic obstructive pulmonary disease
- Pulmonary edema
- Pulmonary embolism
- Pleural effusion
- Idiopathic pulmonary fibrosis
- Interstitial pneumonitis
- Inhalation of foreign body
- Metastasis to lungs
In the great vessels and mediastinum:
- Congestive heart failure
- Pericardial effusion
In the chest wall:
- Aortic aneurysm
- Aortic dissection
- Anomalies of great vessels
- Mediastinal tumor, cyst
- Fractures of ribs
How this procedure is performed
Two views are usually taken:
Before the procedure, remove all clothing and accessories and change into a hospital gown.
When taking a PA view of the chest, the chest is placed against the photographic plate while standing, chin raised, with both hands on the hips, palms out, and the elbows and shoulders in a forward position.
When taking a lateral view of the chest, both hands are raised above the head while standing and the left shoulder is lightly placed against the photographic plate.
For the picture to be clear without blurring, take a deep breath and hold it while the picture is being taken.
Exposed film is developed, washed, and dried. Then a radiologist (a physician specialist experienced in X-ray and other radiology examinations) places the X-ray film over an illumination box and interprets it. When necessary, it is interpreted in comparison to past film.
- PA (posterior-anterior) view. X-rays from an X-ray tube behind the patient's back pass through the body and create an image when they reach the film in front of the chest.
- Lateral view. One of the patient's sides (usually the right) is irradiated with X-ray, and the image is produced on film on the other side.
No special preparation is needed.
Remove all clothing and jewelry and change into an X-ray gown.
When the X-ray is being taken, be still. Breathe in and hold your breath.
Women who are pregnant or suspect pregnancy should inform their doctors or X-ray technologists.
A radiologist (a physician specialist trained to interpret X-ray images or other radiology exams, such as CAT scans, MRI, mammography, etc.) reviews the chest X-ray and reports the results to your personal doctor.
The doctor's office informs patients when their results are in, and what they mean. The office uses the results as a reference in evaluating and treating patients.
Chest radiography uses X-ray, which is a type of ionizing radiation that can potentially change chemical and genetic structures in the human body.
Patients are exposed to far less radiation now than they were in the past because X-rays are collimated so that there is almost no X-ray exposure outside the area of examination, X-rays pass through a filter before being irradiated on the body, and high-speed film is used.
For the safety of patients, radiology technologists and radiologists conduct X-ray exams under guidelines set by national and international radiology protection councils.
To minimize radiation exposure to the reproductive organs, a lead apron/shield can be placed over the testicles (for women, over the pelvic region).
A patient is exposed to 20 miliroentgens of radiation during a typical abdominal X-ray procedure. But considering that one is exposed to 100 miliroentgens a year from ultraviolet rays and small traces of uranium in the soil, radiation exposure from such examinations is really very little, and far outweighs the potential risk.
Women should inform their doctor or X-ray technologist if they are pregnant or suspect pregnancy. Special care will be taken during X-ray exams; otherwise, alternative exams such as ultrasonography can be done instead of X-rays.
Chest radiographs are not always conclusive. For example, in the early stage of lung cancer, when the mass is very small and does not cause airway obstruction or pneumonia, chest X-rays may appear normal.
Chest X-rays can be normal with asthma.
Patients with ischemic heart disease or valvular heart disease can have normal chest radiographs as long as the heart is not enlarged and lungs are free of fluid (a condition called pulmonary edema).
Chest radiography must always be interpreted with reference to physical examinations, the patient's current condition, and the patient's past disease history. For example, if a patient takes a chest X-ray as part of an annual check-up, and there are no symptoms and the chest radiography is normal, that means that in all likelihood the patient's lungs, heart, and chest structure are normal. But, if a middle-aged patient with persistent coughing and sputum who has been smoking for decades has a normal chest radiography, that only means that the patient doesn't have pneumonia or permanent lung damage from COPD (chronic obstructive pulmonary disease.) It doesn't mean that the patient is normal and healthy. In this case, the patient's condition can be further evaluated with a pulmonary function test or CAT scan.
If one's chest X-rays are normal but there are symptoms, or if the chest X-rays are not enough to make a diagnosis, additional examinations may be needed. Radiological exams (such as oblique chest X-ray, chest tomography, CAT scan, MRI, and angiography) and nuclear imaging procedures (such as radioisotope scan, SPECT, and PET scan) can be done as or when needed. Spirometer, arterial blood gas analysis and other pulmonary function tests, bronchoscopy (a procedure in which a thin flexible hose called a bronchoscope passes through the wind pipe for visual inspection of the tracheobronchial tree), bronchoscopic biopsy, transbronchial lung biopsy, percutaneous lung biopsy, and mediastinoscopy can be done for confirmative diagnosis.