Increased Radiation Exposure After a CT Software Upgrade: A Qualitative Instrumental Case Study (Preprint)

BACKGROUND Software upgrades in medical imaging systems are routinely implemented to improve functionality and performance, but they may also introduce unintended changes in system behaviour that affect patient safety. Evidence on how such incidents manifest within imaging workflows remains limited. OBJECTIVE This study aimed to analyze a software upgrade–related incident in computed tomography (CT) that resulted in unintended increases in radiation dose, using established patient safety and health information technology (HIT) frameworks. METHODS A de-identified incident report from a national incident reporting repository was analyzed using a combined deductive and inductive qualitative approach. Deductive analysis applied the International Classification for Patient Safety (ICPS), the Health Information Technology Classification System (HIT-CS), and the 18-step medical imaging process workflow. Inductive thematic analysis was conducted to identify contextual factors within the incident narrative. RESULTS The incident was classified as a technical HIT issue related to software functionality, with incorrect machine output resulting in increased radiation dose despite unchanged examination protocols. Under ICPS, the event was categorized as a medical device/system incident with communication and technology design as contributing factors. Workflow analysis identified image acquisition as the primary step where the incident manifested, with detection occurring during retrospective review. Thematic analysis highlighted limited visibility of software-induced changes and reliance on retrospective monitoring, informing the development of preventive and corrective strategies. CONCLUSIONS This study demonstrates that software upgrade–related HIT incidents in CT imaging can lead to unintended increases in radiation dose during routine clinical use.