Effective doses to patients undergoing thoracic computed tomography examinations

Area of Science:

• Radiology
• Medical Physics
• Diagnostic Imaging

Background:

• Computed tomography (CT) is a vital diagnostic tool.
• Radiation dose in CT examinations is a significant concern for patient safety.
• Optimizing CT protocols is crucial for minimizing radiation exposure.

Purpose of the Study:

• To investigate the relationship between patient size and X-ray technique factors in chest CT.
• To determine how effective radiation doses vary with patient weight.
• To assess the impact of current CT protocols on patient radiation exposure.

Main Methods:

• Collected technique factors (kVp, mAs, etc.) and patient data (weight, dimensions) for 44 chest CT scans.
• Modeled irradiated patient mass as a water cylinder to compute energy imparted.
• Calculated effective doses considering patient weight and energy imparted.

Main Results:

• Chest CT protocols did not correlate tube current (mAs) with patient weight (r²=0.06).
• Energy imparted increased with patient weight (e.g., 85 mJ for 10 kg vs. 310 mJ for 70 kg).
• Effective dose showed an inverse correlation with patient weight (e.g., 9.6 mSv for 10 kg vs. 5.4 mSv for 70 kg).

Conclusions:

• Current chest CT technique factors result in disproportionately high radiation doses for smaller patients.
• Adjusting CT technique factors based on patient size can significantly reduce radiation exposure.
• Personalized CT protocols are recommended for optimizing patient safety and diagnostic efficacy.