by Jones P
(Low-Dose Computed Tomography; Low-Dose Helical CT Scan)


A low-dose CT scan is a type of x-ray. It can create detailed pictures of the lungs. This scan creates more details than a basic x-ray but uses less radiation than regular CT scan.

Reasons for Procedure

A low-dose scan is used to look for lung cancer in people without symptoms. It can help to see early changes in the lung that may suggest cancer. Lung cancer is a leading cause of cancer deaths. The rate of survival may improve with early diagnosis and treatment.

The test is only recommended for those who have all 3 risk factors for lung cancer listed below

  • History of heavy smoking
  • Current smoker or a former smoker who quit within 15 years
  • Age between 55 and 80 years

The scan itself cannot confirm cancer. If this scan shows an abnormal area, more tests will need to be done to see if there is cancer.

Possible Complications

Problems from the procedure are rare, but all procedures have some risk. Screening tests can lead to unnecessary procedures and stress. This can happen if:

  • The test suggests cancer when there is no cancer. Other tests and surgery will be needed to look for cancer. The tests and process can be stressful.
  • The cancer that is found would have never caused problems. Some very small cancers may never grow enough to cause problems before the natural end of life. It is not always possible to know this about cancers found during screening. This means that treatment of the cancer was not necessary.

A CT scan uses radiation to make the images. Repeated doses of radiation increase the risk of cancer. The risk increases with the number of tests. This scan uses a lower amount of radiation than other CT scans but there is still a risk.

What to Expect

Prior to Procedure

The doctor will talk about the risks and benefits of a low-dose CT scan. It will include your risk of lung cancer based on smoking history. Both the number of cigarettes per day and years smoking will be reviewed.

Before the test, you may need to:

  • Change into a gown
  • Remove all jewelry, hair clips, dentures, and other objects

Description of the Procedure

You will lie on a table with your arms over your head. The table will slide into the center of the scanner. A technician may ask you to hold your breath and stay still for a short time. The scan often takes less than 1 minute.

How Long Will It Take?

The appointment may take about 30 minutes. The test itself is less than 1 minute.

Will It Hurt?

It is a painless procedure.

Post-procedure Care

You can leave as soon as the tests are done.

Your doctor will call about the tests results. A positive test means that an abnormal area was found. Other tests will be needed to see if there is cancer. A negative test means that there were no suspicious areas.

Call Your Doctor

Call your doctor if you have any questions or concerns.

If you think you have an emergency, call for emergency medical services right away.


American Lung Association 

NIH National Cancer Institute 


Canadian Cancer Society 

The Lung Association 


Lung Cancer Screening (PDQ®)–Health Professional Version. NIH National Cancer Institute website. Available at: Updated April 1, 2020. Accessed May 19, 2020.

Who should be screened for lung cancer? Center for Disease Control (CDC) website. Available at: Updated September 18, 2019. Accessed May 19, 2020.

Saved by the Scan. American Lung Association website. Available at: Accessed May 19, 2020.

Lung Cancer Screening. EBSCO Dynamed website. Available at: . Updated February 24, 2020. Accessed May 19, 2020.

Revision Information