Low-Dose Screening CT Scan
What is a Low-Dose Screening CT Scan?
Lung cancer screening is done with annual low-dose CT scans, using a special technique with an extremely small amount of radiation. Screening CT scans are done to look for lung nodules that may represent lung cancer.
Lung nodules are small areas of lung that are denser than the surrounding normal lung. The vast majority (at least 98 percent) of these nodules are benign, or not cancer. However, in people at a high risk for lung cancer such as heavy smokers, cancers may be found when they are small and potentially curable. People at a low risk for lung cancer should not enroll in a lung cancer screening program. Your physician will help you determine whether you are eligible.
Low-dose screening CT for lung cancer has been proven to reduce mortality from lung cancer based on randomized clinical trials. For people at high risk for lung cancer, the benefits of receiving such a screening dramatically outweigh the risks of not having the screening, especially if lung cancer is detected. Early detection may provide opportunity for cure if lung cancer is found. Enrollment in this program is a commitment to at least two years of screening studies for at least a total of three low-dose CT scans.
Patients who meet the following criteria are eligible for an annual low-dose CT scan (LDCT) to screen for lung cancer:
- Age 55 to 79 years old
- A 30 "pack year" or greater history of smoking (a "pack year" is calculated from multiplying the number of packs of cigarettes smoked per day by the number of years a person has smoked − a pack is 20 cigarettes)
- Either currently smoke or have quit in the past 15 years
- No symptoms of lung cancer such as cough, shortness of breath, or chest pain
- Able and willing to tolerate treatment if lung cancer is discovered
What should I expect before the exam?
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.
What will I experience during the exam?
- Scanning: A CT technologist will bring you into the CT scan room and will give instructions on how long you need to hold your breath. You should cough vigorously just before the scan to clear any mucus from your breathing tubes (bronchi). 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 the exam and how will I learn my results?
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 arrange for follow-up as needed. You may receive additional letters from the radiology department about results and about booking followup imaging.
How do I arrange a lung cancer screening CT?
Lung cancer screening CTs require an order from a physician. Please contact your physician to arrange an appointment.
Radiologyinfo.org for Patients
The radiology information resource for patients. RadiologyInfo.org tells you how various X-ray, CT, MRI, ultrasound, radiation therapy and other procedures are performed. It also addresses what you may experience and how to prepare for the exams. The website contains over 200 procedure, exam and disease descriptions covering diagnostic and interventional radiology, nuclear medicine, radiation therapy and radiation safety and is updated frequently with new information. All material on the RadiologyInfo.org website is reviewed and approved by experts in the field of radiology from the ACR and RSNA, as well as other professional radiology organizations.