What is the radiation dose of a Computed Tomography (CT) scan measured in milligray (mGy)?

From the Guidelines

The radiation dose of a CT scan can be as low as 0.5 mSv, which is equivalent to 50 milligray (mGy), when using optimized protocols and dose reduction technologies, as recommended in the most recent guidelines 1.

Key Factors Influencing Radiation Dose

• The body part being scanned: chest CT scans averaging 5-7 mSv (500-700 mGy), abdominal CT scans around 8-10 mSv (800-1000 mGy), and head CT scans about 2 mSv (200 mGy) 1
• Patient size and age: larger patients require larger exposures, and children are more sensitive to radiation effects 1
• Scanner protocol selection: variables such as scan length, x-ray beam intensity, tube potential, and tube current can significantly impact patient dose 1

Dose Reduction Strategies

• Using iterative reconstruction and automatic exposure control to minimize radiation exposure while maintaining image quality 1
• Suspending the automatic exposure control function and applying a specific tube voltage and current according to patient size 1
• Using a low radiation dose protocol, approximately one third of that required for the inspiratory film, to detect air trapping on the expiratory film 1

Importance of Minimizing Radiation Exposure

• Healthcare providers aim to follow the ALARA principle (As Low As Reasonably Achievable) to minimize unnecessary radiation exposure, particularly for children and pregnant women who are more sensitive to radiation effects 1
• The average person receives about 3 mSv annually from natural background radiation, and CT scans should be used judiciously to avoid excessive radiation exposure 1

From the Research

Radiation Dose of CT Scan

• The radiation dose of a CT scan is a concern in the medical field, with studies focusing on reducing the dose while maintaining diagnostic image quality 2.
• CT scan parameters such as detector configuration, tube current, tube potential, reconstruction algorithm, patient positioning, scan range, reconstructed slice thickness, and pitch can be manipulated to reduce patient radiation dose 2.
• The use of CT scans has increased over the years, with trends showing a higher imaging rate in 2016 compared to 2000, especially among adults and older adults 3.
• However, the annual growth in imaging rates for CT scans has slowed down over time, with a decline in growth rate from 11.6% to 3.7% among adults and from 9.5% to 5.2% among older adults 3.
• Advances in technology have made it possible to reduce radiation doses in CT scans, with ongoing studies aimed at further optimization 4.
• Other imaging modalities like MRI and ultrasound do not involve radiation, but have their own limitations and advantages 5, 4.
• The trade-off between image quality and patient radiation dose is a significant consideration in CT scans, with the goal of achieving diagnostic image quality while minimizing radiation exposure 2, 5.