Special consideration is brought up for women regarding safety issue of radiation exposure to the breasts with coronary CT angiography (CTA). The purpose of this study was to measure the surface radiation dose received by the adult female breast during coronary CTA and to evaluate the effectiveness of lower tube voltage and cranial breast displacement to reduce breast radiation exposure.

The subjects were 276 women (mean age, 57.8 ± 10.2 years) who underwent coronary CTA between March 2014 and June 2015. Patients were divided into four different protocol groups by tube voltages of 120 or 100 kVp and use of cranial breast displacement; group A with no cranial displacement at 120 kVp (n=69), group B with no cranial displacement at 100 kVp (n=69), group C with cranial displacement at 120 kVp (n=69), group D with cranial displacement at 100 kVp (n=69). Direct measurement of breast...

The breast surface dose was significantly lower in groups B and D (p<0.001; group A, 35.9 ± 16.6 mGy; group B, 22.1 ± 10.0 mGy; group C, 39.2 ± 17.3 mGy, group D, 23.1 ± 8.3 mGy). The greatest dose reduction was observed in the right upper inner quadrant (43.0%) followed by in the left upper inner quadrant (42.6%). No significant difference in the breast surface dose was seen with same tube voltages but different use of cranial breast displacement (p=0.262, group A vs group...

Lower tube voltage was effective to reduce breast surface dose during coronary CTA. Significant reduction of the fibroglandular tissue of the breasts within the scan range of coronary CTA was obtained using cranial breast displacement with no significant change in breast surface dose. Both lower tube voltage and cranial displacement of the breasts can be applied during coronary CTA that may have the most benefit from this technique to avoid radiation risk in the radiosensitive female breasts.