Which dose metric is commonly included in DR dose tracking?

• A. Kilovolt peak (kVp)
• B. Exposure Index (EI)
• C. Computed Tomography Dose Index (CTDI)
• D. Dose Area Product (DAP)

Answer: (C)

Dose tracking uses standardized quantities that reflect how much radiation a patient receives. In computed tomography, the established metric is the CT dose index, which describes the dose delivered per rotation (per slice) in a reference phantom. This value is reported as CTDIvol to account for the scan geometry and pitch, and it serves as the building block for related measures like the dose-length product, which combines CTDIvol with the scanned length to summarize the entire CT examination.

Including the CT dose index in dose tracking is common because it provides a consistent, modality-specific measure of CT exposure that can be integrated with dose data from other imaging studies to form a complete patient dose history. It’s a universal, CT-wide standard that helps compare protocols, monitor trends, and guide dose reduction efforts across different scanners and facilities.

Other items like kVp are technical settings rather than dose quantities; the Exposure Index relates to detector exposure in DR but isn’t a standardized patient-dose metric across modalities; and dose-area product is more typical for radiography and fluoroscopy. CTDI is the appropriate, CT-specific metric used in dose tracking.