Dual-Source CT Angiography: Radiation Dose Optimization Using Phantom Study

This phantom study evaluated radiation dose characteristics of dual-source CT (DSCT) angiography across various acquisition parameters using an anthropomorphic chest phantom, with the goal of identifying protocol combinations that minimize radiation dose while preserving adequate image quality.

Varying tube voltage (80–140 kVp) and tube current (75–700 mAs) systematically in a controlled phantom setting, the study characterized dose-quality trade-offs. High-pitch dual-source acquisition with reduced tube current and voltage produced substantially lower dose than standard acquisition while maintaining image quality within acceptable radiological thresholds. Effective dose estimates ranged from 1.3 to 14.2 mSv depending on protocol.

Phantom studies occupy a methodologically limited position in the evidence hierarchy: they characterize physical measurement properties in an artificial model rather than measuring clinical outcomes or diagnostic accuracy in patients. Their value is in protocol development and radiation safety benchmarking rather than in establishing clinical utility.

The practical context: dual-source CT enables high-pitch (up to 3.4) helical acquisition of the heart during systole in a single 0.25-second acquisition, dramatically reducing radiation compared with standard multi-beat protocols. These phantom data contributed to the protocol development that enabled sub-mSv cardiac CT in appropriately selected patients.

We rate the evidence limited. A phantom study characterizing radiation dose optimization for dual-source cardiac CT — technically valuable for protocol development but methodologically peripheral to clinical cardiovascular outcome questions.