Radiation doses and risks in chest computed tomography examinations

Area of Science:

• Medical Imaging
• Radiology
• Radiation Oncology

Background:

• Chest computed tomography (CT) involves radiation exposure, necessitating accurate dose assessment.
• Understanding radiation risks, such as cancer induction, is crucial for patient safety in medical imaging.

Purpose of the Study:

• To determine effective doses and associated cancer risks for patients undergoing chest CT examinations.
• To evaluate dose reduction strategies, including low-dose protocols for specific patient groups.

Main Methods:

• Calculated patient effective doses using dose-length product (DLP) from 16-slice CT scanners.
• Applied age-dependent conversion coefficients for chest CT examinations.
• Estimated nominal cancer risks using data from the Committee of the Biological Effects of Ionizing Radiation (BEIR) Report VII.

Main Results:

• Standard chest CT effective doses range from 1.7 mSv (newborns) to 5.4 mSv (adults).
• A low-dose protocol for a 5-year-old with cystic fibrosis resulted in an effective dose of 0.55 mSv, a fourfold reduction.
• This low dose corresponds to a nominal excess cancer risk of 1.5 per 10,000 individuals, with half being fatal.

Conclusions:

• Chest CT examinations should be performed only when the clinical benefit outweighs the small radiation risk.
• Low-dose CT protocols can substantially decrease radiation exposure and associated risks, particularly in pediatric patients.
• Accurate dose assessment and risk estimation are vital for informed clinical decision-making in diagnostic imaging.