From the Guidelines
The radiation dose of a non-contrast computed tomography (CT) scan of the chest is approximately 8 mSv. This estimate is based on a systematic review published in the Journal of the American Medical Association (JAMA) in 2012 1. The study notes that there is substantial variation in actual clinical practice, but 8 mSv is the estimated dose for a diagnostic chest CT. Some key points to consider when interpreting this dose include:
- The effective dose of radiation from low-dose CT (LDCT) is estimated to be 1.5 mSv per examination, but this is not the same as a standard non-contrast CT scan of the chest 1.
- The radiation dose from a CT scan can vary based on factors such as the specific protocol, scanner type, patient size, and institutional settings.
- The potential risks of radiation exposure from CT scans, including the risk of cancer, must be carefully weighed against the potential benefits of the scan, particularly in younger individuals or those with lower risk of developing lung cancer 1. The radiation dose of 8 mSv is a crucial consideration in the context of real-life clinical medicine, where the goal is to minimize harm while maximizing benefit, and a non-contrast CT scan of the chest should only be ordered when the potential benefits outweigh the potential risks.
From the Research
Radiation Dose of Non-Contrast Computed Tomography (CT) Scan of the Chest
- The radiation dose of a non-contrast computed tomography (CT) scan of the chest can vary depending on several factors, including the type of CT scanner, patient size, and scanning protocol 2, 3, 4, 5, 6.
- Studies have reported the following radiation doses for chest CT scans:
- Mean effective dose: 22.4 ± 5.9 mSv per procedure 2
- Mean effective dose: 1.7-5.4 mSv for standard chest CT examinations 3
- Radiation doses: 15.6-21.4 mSv for standard-dose CT and 7.8-10.7 mSv for 50%-reduced-dose CT 4
- Mean CTDIvol and DLP values: 2.1 mGy and 85.1 mGy·cm for low-dose CT, 9.7 mGy and 392.3 mGy·cm for helical CT, and 18.2 mGy and 813.9 mGy·cm for angio CT 5
- Mean volume CT dose index (CTDIvol): 279.39 mGy and 227.14 mGy, mean dose length product (DLP) values: 655.14 mGy·cm and 789.61 mGy·cm, and mean effective dose (ED) values: 9.171 mSv and 11.054 mSv 6
- These studies suggest that the radiation dose of a non-contrast CT scan of the chest can be optimized by using lower dose scanning protocols, such as low-dose CT or iterative reconstruction, without compromising image quality 4, 5, 6.