Progressive X-ray tube degradation detected via daily mammography quality control

Abstract

This study evaluated whether routine daily quality control (QC) tests can anticipate X-ray tube degradation in a digital mammography system. Over 30 months, tube loading, contrast-to-noise ratio (CNR), and image quality scores were extracted from daily QC tests and analysed alongside a documented tube failure in September 2024. These results were compared with annual tube output measurements and environmental data. A progressive rise in tube loading was observed prior to tube failure, increasing from 84.45 to 94.58 mAs (12.0%). The Mann-Kendall test confirmed a significant upward trend (τ = 0.461; <i>p</i> &lt; 0.001), with Sen's slope indicating +0.19 mAs/month. Despite this, CNR values remained stable (mean = 14.76 ± 0.20), and image quality showed no degradation. However, tube output declined consistently (from 30.95 ± 3.08 to 28.76 ± 0.36 μGy/mAs), confirming reduced efficiency. Temperature and humidity remained within recommended limits. These findings suggest that gradual increases in tube loading can indicate early tube degradation, even when image quality remains unaffected. Beyond confirming equipment performance, daily QC may serve as a strategic tool to detect early signs of degradation, extend device lifespan, reduce unplanned downtime, and promote patient safety without added costs.