What is the radiation dose of a Computed Tomography (CT) scan of the spine?

From the Guidelines

A typical spine CT scan delivers a radiation dose of approximately 6-10 millisieverts (mSv), though this can vary based on the specific protocol, equipment used, and the area of the spine being examined.

Key Considerations

• Lumbar spine CTs generally have higher doses (6-10 mSv) compared to cervical spine scans (3-6 mSv) 1.
• This radiation exposure is equivalent to about 2-3 years of natural background radiation.
• Modern CT scanners often incorporate dose reduction technologies like iterative reconstruction algorithms and automatic exposure control that can reduce radiation by 30-60% while maintaining diagnostic image quality 1.

Radiation Risk and Diagnostic Benefits

• The radiation risk from a single spine CT is considered relatively low for most adults, with the diagnostic benefits typically outweighing potential risks.
• However, radiation exposure is cumulative over a lifetime, so healthcare providers aim to use the lowest dose necessary for diagnosis.

Patient Considerations

• Patients should inform their doctor about previous radiation exposures and any possibility of pregnancy before undergoing a CT scan, as alternative imaging methods like MRI (which uses no radiation) might be more appropriate in certain situations.

Best Practices

• Obtaining sagittal and coronal spine images from existing chest, abdomen, and pelvis CT data is a recommended practice that is both effective and radiation dose sparing 1.

From the Research

Radiation Dose of CT Scan of the Spine

• The radiation dose of a Computed Tomography (CT) scan of the spine can vary depending on several factors, including the specific protocol used and the patient's body mass index (BMI) 2.
• Studies have shown that the use of automatic exposure control (AEC) and BMI-based protocols can help reduce the radiation dose of CT scans of the lumbar spine without compromising image quality 2.
• One study found that the combined use of BMI and AEC reduced the radiation dose of CT volume scans of the lumbar spine by up to 50% 2.
• Another study compared the image quality of low-dose CT scans of the lumbar spine with radiography and found that low-dose CT had superior image quality and provided more anatomical and diagnostic information 3.
• The effective dose of a low-dose CT scan of the lumbar spine can be as low as 1-1.1 mSv, which is comparable to or even lower than the effective dose of radiography 3.
• In terms of specific dose reduction techniques, one study found that reducing the kV and mAs settings on the CT scanner can reduce the radiation dose by up to 72% without compromising image quality 4.
• Another study found that using a dose-optimized protocol with a lower mAs setting can reduce the radiation dose by up to 51% without compromising image quality 5.

Dose Reduction Techniques

• Reducing the kV and mAs settings on the CT scanner can help reduce the radiation dose 4.
• Using a dose-optimized protocol with a lower mAs setting can help reduce the radiation dose 5.
• Combining the use of BMI and AEC can help reduce the radiation dose of CT scans of the lumbar spine 2.
• Using iterative reconstruction techniques can help reduce the radiation dose while maintaining image quality 6.

Image Quality and Diagnostic Information

• Low-dose CT scans of the lumbar spine can provide superior image quality and more anatomical and diagnostic information compared to radiography 3.
• The use of dose reduction techniques can help maintain image quality while reducing the radiation dose 4, 5, 2.
• The diagnostic information provided by low-dose CT scans of the lumbar spine can be comparable to or even better than that provided by radiography 3.