What is the estimated radiation dose of a computed tomography (CT) scan of the chest, abdomen, and pelvis without contrast?

From the Guidelines

The estimated radiation dose for a CT scan of the chest, abdomen, and pelvis without contrast is approximately 20-30 millisieverts (mSv). This is considered a moderate to high radiation dose compared to other medical imaging procedures. The actual dose can vary depending on the specific CT scanner used, the patient's size, the scan parameters selected by the technologist, and whether dose-reduction techniques are employed.

Key Considerations

• This type of comprehensive CT scan delivers a higher radiation dose because it covers a large portion of the body and is performed without contrast.
• For context, this radiation exposure is roughly equivalent to 7-10 years of natural background radiation that we receive from our environment.
• While this dose presents a small theoretical increase in cancer risk, the immediate diagnostic benefit typically far outweighs this potential long-term risk when the scan is medically necessary, as noted in studies such as 1.

Radiation Exposure

• Modern CT scanners often incorporate dose-reduction technologies to minimize radiation exposure while maintaining diagnostic image quality.
• Strategies to reduce the radiation dose include suspending the automatic exposure control function on the CT scanner and applying a specific tube voltage and current according to patient size, as discussed in 1.
• Using this approach, the overall dose can be significantly reduced, although it will vary depending on the CT scanner and patient size.

Clinical Decision Making

• Decisions about CT technique at individual institutions need to factor in local resources, including the capabilities of available CT scanner(s), availability of support, and experience of the CT technologists and interpreting radiologist(s), as highlighted in 1.
• The most recent and highest quality study, 1, suggests that proactive patient preparation and optimization of CT technique can help minimize radiation exposure while maintaining diagnostic image quality.

From the Research

Estimated Radiation Dose for CT Scan

The estimated radiation dose for a CT CHEST ABDOMEN PELVIS WO CONTRAST scan can be broken down into several key points:

• The mean effective dose per procedure for a chest, abdomen, and pelvis CT scan was found to be 22.4 ± 5.9 mSv 2.
• The volume CT dose index (CTDIvol) was 22.94 ± 5.64 mGy, and the dose-length product was 1493.8 ± 392.1 mGy cm 2.
• Patient size can significantly impact the radiation dose, with larger patients requiring higher doses to achieve adequate image quality 3.
• The average volume CT dose index for a 60-kg patient was approximately 11 mGy, increasing to 22 mGy for an 80-kg patient and 33 mGy for a 100-kg patient 3.
• Organ doses can also vary significantly depending on patient size, with median doses to the colon, stomach, and liver ranging from 25 mGy for 60-kg patients to 34 mGy for 100-kg patients 3.
• Using body size-specific effective dose conversion coefficients can provide more accurate estimates of radiation dose than age-specific factors 4.
• For low-dose chest CT examinations, the estimated effective dose can be as low as 1.4 mSv, with organ doses ranging from 1.6 to 2.4 mSv depending on the tissue-weighting factors used 5.
• Institutional dose reports have shown varying radiation doses for different types of CT examinations, with median effective doses ranging from 1.76 mSv for neck CT to 6.8 mSv for abdominal CT 6.

Key Factors Influencing Radiation Dose

Some key factors that can influence the radiation dose for a CT CHEST ABDOMEN PELVIS WO CONTRAST scan include:

• Patient size and weight
• Type of CT scanner and protocol used
• Volume CT dose index (CTDIvol) and dose-length product
• Organ doses and tissue-weighting factors
• Use of automatic exposure control and other dose-reduction techniques
• Institutional and national diagnostic reference levels (DRLs) 2, 3, 4, 5, 6.