Low-Dose CT Scan

Massachusetts General Hospital Imaging offers lung cancer screening by dedicated thoracic radiologists using low-dose CT scans (LDCT).

Lung cancer can be detected using low-dose CT scans (LDCT), which are available on our main campus in Boston and at our locations in Waltham, Chelsea and Danvers.

At Mass General, all images are read by dedicated thoracic radiologists who specialize in the detection and management of lung nodules. They are part of a multidisciplinary team that offers subspecialty expertise in the detection and treatment of lung cancer.

Learn about eligibility for lung screening

Active smokers should enter a smoking cessation program. Screening is not an alternative to smoking cessation.

LDCT Overview

  • Requires a physician's referral
  • Not covered by most insurance plans
    • Follow-up CT scans are typically covered by insurance plans if an abnormality is detected
  • Does not involve the use of contrast
  • Carries a low radiation dose
  • Has a high rate of false positive findings, which may lead to follow-up exams, additional cost, additional radiation exposure and patient anxiety
    • It is important that a health care provider manage follow up care for patients with a positive finding

Read our FAQs to learn more about the risks associated with lung cancer screening, including incidental findings and radiation risk.

CT lung cancer screening

Small nodule discovered by CT in the left lung (A)
enlarged on follow-up CT scan (B) and was found to
be an adenocarcinoma at surgery.

LDCT in Depth

On July 6, 2011, the New England Journal of Medicine published results from the National Lung Cancer Screening Trial (NLST) conducted by the National Cancer Institute (NCI) and the American College of Radiology Imaging Network (ACRIN). This study, the only randomized control trial of lung cancer screening that has been completed, included more than 50,000 patients.

The results demonstrated a mortality benefit of 20% when LDCT is used to screen high-risk patients for early lung cancer. In other words, 20% fewer deaths were reported during the study among a group of patients who received LDCT scanning versus a control group of patients who did not.

In December 2013, the US Preventive Services Task Force (USPSTF) finalized recommendations to screen high-risk patients for lung cancer with LDCT based on findings from the NLST. It is the only screening test for lung cancer recommended by the USPSTF. Read more

What should I expect BEFORE a LDCT?

There is no special preparation for a LDCT. You do not need to fast or get an injection.

  • Medications: Keep to your regular medication schedule prescribed to you by your doctor, and let us know what medications you have taken prior to your test.
  • Food and drink: There are no restrictions on food and drink.
  • When to arrive: Please arrive 15 minutes before your scheduled appointment time.
  • What to wear: Dress in comfortable clothing. You may be asked to change into a hospital gown if your clothing contains metal (e.g., a bra or zipper). You may also be asked to remove jewelry or anything that might interfere with your scan. Although the scan is conducted in a secure environment, it is best to leave valuable items at home.

If you have had a previous chest CT at another hospital, please notify your doctor and authorize Mass General to get a copy before you have a LDCT.

What will I experience DURING a LDCT?

  • Scanning: A CT technologist will bring you into the CT scan room where you will lie on your back on a table with your hands over your head. The technologist will position your body within the large doughnut-shaped scanner ring which holds the X-ray tube and electronic detector. The technologist will leave the room but is in full view and communication with you during the exam.
    • The scanner does not touch you, and you do not feel the X-rays. It makes some noise, and the table may move slightly to adjust for a better view. It is important to lie still and hold your breath (no more than a few seconds) when asked.
    • During the scan, a thin beam of X-ray is focused on a specific part of your body. The X-ray tube moves very rapidly around this area, capturing multiple images from different angles to create a cross-sectional picture. The data goes to the electronic detector and to a computer, which constructs an image for the radiologist to read.
  • Length of scan: Most examinations last approximately 15 minutes, but the actual scanning takes about two minutes. You may leave once it is completed; you do not wait for the results.

What should I expect AFTER a LDCT?

You have no restrictions after having a scan and can go about your normal activities.

A thoracic radiologist will read your scan, using any of your prior scans for comparison, and send your doctor a report. Your doctor will notify you of the results and organize follow-up if needed.

Mass General Imaging introduces CT lung-cancer screening

Research shows a clear benefit for CT lung-cancer screening among individuals who meet strict criteria. Patients and referrers should understand both the benefit and the potential for false positive results.

National experts issue statement on lung cancer screening

The U.S. Preventive Services Task Force recommends low-dose CT scans to screen high-risk patients for lung cancer.

Mass General thoracic imaging expert answers questions about lung cancer screening

Director of Thoracic Imaging and Intervention in the Mass General Department of Radiology, Dr. Jo-Anne Shepard explains what the recent lung cancer screening recommendations mean for patients.

National experts publish final lung cancer screening recommendations

With implications for insurance coverage, the U.S. Preventive Services Task Force recommends annual low-dose CT scans to reduce lung cancer deaths.


Lung Screening at Mass General

Learn about eligibility for lung cancer screening at Mass General.


Schedule an exam at Mass General Imaging

Find scheduling information for patients and referring physicians.


Imaging experts, focused on you

Every scan at Mass General Imaging is read by a radiologist with specialty training in the area of the body being studied.