Reject Analysis in Digital Radiography and Computed Tomography: A Belgian Imaging Department Case Study

Area of Science:

• Radiology
• Medical Imaging Quality Assurance
• Radiation Dose Management

Background:

• Reject analysis is crucial for quality assurance in digital radiography (DR).
• Data on computed tomography (CT) reject analysis is limited.
• A standardized method for comparing DR and CT rejects is needed.

Purpose of the Study:

• To establish a straightforward benchmark for reject analysis in both DR and CT.
• To compare reject rates, reasons, and associated radiation doses for DR and CT.

Main Methods:

• Retrospective observational study of 107,277 DR and 20,659 CT acquisitions over 18 months.
• Rejected acquisitions identified using the Dose Archiving and Communication System (DACS).
• Analysis included reject rates, causes, and supplementary radiation dose.

Main Results:

• DR reject rate was 8.3%; CT reject rate was 2.5%.
• Cumulative effective dose (ED) for DR rejects was 377.3 mSv; for CT rejects, it was 1267.4 mSv.
• Incorrect patient positioning was the primary reason for rejection in both DR (61%) and CT (44%).

Conclusions:

• A simple, reproducible method for simultaneous DR and CT reject analysis was developed.
• CT rejects, though less frequent, contribute substantially higher radiation doses, highlighting the need for systematic monitoring.
• Understanding rejection patterns can guide improvements in imaging techniques and technologist training.