Not for emergencies. Call 911 or go to the nearest ER immediately for chest pain, severe shortness of breath, stroke symptoms, or any urgent symptom. DOD is not an emergency service.
Chest X-Ray Education Guide
A chest X-ray (chest radiograph) is one of the most common diagnostic imaging studies performed in medicine. It uses a low dose of ionizing radiation to create a 2D image of the structures inside the chest, including the lungs, heart, ribs, and major blood vessels.
Educational content only. This page does not constitute medical advice. Clinical appropriateness is determined by a licensed provider. DOD does not perform or interpret X-rays.
Quick Answer
A chest X-ray uses a brief, low-dose X-ray beam to create a 2D image of the chest. It is commonly used to evaluate the lungs, heart size and shape, bones of the chest wall, and major vessels. A provider order is typically required at outpatient imaging facilities before scheduling. DOD can review chest X-ray order requests for eligible patients in supported states, but DOD does not perform X-rays or interpret results.
How a Chest X-Ray Works
A chest X-ray machine directs a controlled beam of ionizing radiation through the body. Different tissues absorb X-rays at different rates — dense structures like bone appear white on the image, air-filled lungs appear darker, and soft tissues like the heart appear in varying shades of gray. A radiographer (X-ray technologist) positions the patient (typically standing, facing the detector) to obtain the necessary views.
The most common views are the PA (posteroanterior — taken from the back) and the lateral (side) view. Together, these two projections allow the radiologist to evaluate chest structures from two perpendicular angles, improving diagnostic accuracy compared to a single view.
According to RadiologyInfo.org, the radiation dose from a standard PA chest X-ray is among the lowest of any imaging study — approximately 0.1 millisieverts (mSv), comparable to about 10 days of natural background radiation.
What a Chest X-Ray May Be Used to Evaluate
A licensed provider determines whether a chest X-ray is appropriate. A provider may consider a chest X-ray for evaluation of:
Lungs
Pneumonia, pleural effusion, pneumothorax, lung masses, hyperinflation (emphysema), nodules
Heart
Cardiac size and silhouette, signs of heart failure (pulmonary edema, enlarged cardiac shadow)
Chest Wall and Ribs
Rib fractures, bone lesions, soft tissue abnormalities
Mediastinum
Widened mediastinum, mediastinal masses, lymphadenopathy
Major Vessels
Aortic contour, vascular engorgement
Devices and Lines
Pacemaker leads, central lines, endotracheal tubes (in clinical settings)
Educational only. Clinical appropriateness is determined by a licensed provider.
What a Chest X-Ray Cannot Show
Chest X-rays have important limitations. A normal chest X-ray does not rule out all pulmonary or cardiac disease. Chest X-rays may not detect:
Chest X-Ray vs. Chest CT: What Is the Difference?
| Feature | Chest X-Ray | Chest CT |
|---|---|---|
| Technology | Single X-ray projection | Multiple X-ray angles + computer reconstruction |
| Image type | 2D overview | Cross-sectional slices + 3D reconstruction |
| Radiation dose | Very low (~0.1 mSv) | Higher (~7 mSv for standard chest CT) |
| Detail level | Overview — good for gross pathology | High detail — sensitive for small nodules, emboli, parenchymal disease |
| Speed | Very fast — seconds | Fast — 5–15 minutes |
| Contrast | Not used | May use IV iodinated contrast |
| Cost (typical) | Lower | Higher |
A provider determines whether a chest X-ray or CT is more appropriate based on symptoms, clinical history, and the diagnostic question.
Provider Order Requirement
Most outpatient imaging facilities require a valid provider order before scheduling a chest X-ray. A chest X-ray order typically includes the exam type (e.g., "PA and Lateral Chest X-Ray"), clinical indication, ordering provider information and NPI, and results destination. DOD can review chest X-ray order requests for eligible patients in supported states.
Frequently Asked Questions — Chest X-Ray
Sources and Further Reading
- Chest X-Ray — Patient Information — RadiologyInfo.org (ACR / RSNA)
- Chest X-Ray Overview — MedlinePlus (NIH)
- Lung Cancer Screening — Recommendations — U.S. Preventive Services Task Force (USPSTF)
- ACR Appropriateness Criteria — Chest — American College of Radiology (ACR)
Related Education and Order Pages
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Educational content only. DOD is not an imaging center, laboratory, radiology facility, or emergency service. DOD does not perform or interpret X-rays. All clinical decisions should be made by qualified licensed healthcare providers.