Radiation dose estimates in dual-source computed tomography coronary angiography

Area of Science:

• Medical Imaging
• Radiology
• Cardiovascular Imaging

Background:

• Dual-source CT coronary angiography (DSCTCA) is a key diagnostic tool.
• Optimizing radiation dose in DSCTCA is crucial for patient safety.
• ECG-gated pulsing protocols aim to reduce radiation exposure.

Purpose of the Study:

• To quantify and compare radiation dose parameters of DSCTCA using two different ECG-pulsing algorithms.
• To evaluate the impact of varying tube current reduction levels on radiation dose.
• To assess the relationship between heart rate and radiation dose in DSCTCA.

Main Methods:

• Eighty patients underwent contrast-enhanced, retrospectively ECG-gated DSCTCA.
• Two groups (40 patients each) received different tube current reduction protocols: 20% (A(min1)) and 4% (A(min2)) of normal tube current (A(max)).
• Radiation dose parameters, including CTDIvol and estimated effective dose, were measured and analyzed.

Main Results:

• The 4% tube current reduction group (A(min2)) showed significantly lower mean CTDIvol (39.1 mGy) compared to the 20% group (A(min1)) (45.1 mGy) (P < 0.001).
• Radiation dose in the A(min1) group significantly decreased with increasing heart rate (r = -0.82), while no correlation was found in the A(min2) group (r = -0.066).
• Estimated mean effective doses were 8.8 mSv (A(min1)) and 7.8 mSv (A(min2)).

Conclusions:

• A 4% tube current reduction protocol in DSCTCA significantly lowers radiation dose compared to a 20% reduction.
• The 4% protocol provides a radiation dose independent of heart rate, offering consistent dose reduction.
• Optimized ECG-pulsing protocols in DSCTCA are effective in minimizing radiation exposure.