Recent Blog Articles
New advice on melatonin use in children
How to choose period products
Vaccines against the flu and COVID-19: What you need to know
Treatments for rheumatoid arthritis may lower dementia risk
Scoring highly on Alternative Healthy Eating Index lowers risk for many illnesses
Can self-employment promote better cardiovascular health for women?
Why is it so challenging to find a primary care physician?
Harvard Health Ad Watch: A new injection treatment for eczema
3 simple swaps for better heart health
I’m too young to have Alzheimer’s disease or dementia, right?
What is the test?
Doctors have used x-rays for over a century to see inside the body in order to diagnose a variety of problems, including cancer, fractures, and pneumonia. During this test, you usually stand in front of a photographic plate while a machine sends x-rays, a type of radiation, through your body. Originally, a photograph of internal structures was produced on film; nowadays, the image created by the x-rays goes directly into a computer. Dense structures, such as bone, appear white on the x-ray films because they absorb many of the x-ray beams and block them from reaching the plate. Hollow body parts, such as lungs, appear dark because x-rays pass through them.
Back x-rays and chest x-rays are among the most common conventional x-ray tests. You should not have an x-ray if you're pregnant unless the risk is considered and special precautions are taken, because radiation can be harmful to a developing fetus.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
I'd like to receive access to Harvard Health Online for only $4.99 a month.Sign Me Up
Already a member? Login ».
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Free Healthbeat Signup
Get the latest in health news delivered to your inbox!