Surveillance (epidemiology)

Surveillance in epidemiology refers to the active systematic collection and analysis of data related to diseases or conditions in a population to inform public health actions.

In epidemiology, surveillance may be either active or passive:

• passive surveillance: collection of data from established reporting systems
• active surveillance: proactive search for cases of a disease

Surveillance need not involve directly diagnostic data. Over the last few decades, methods, sometimes based on machine learning, have appeared that use digital data created by a population such as internet searches or even Twitter tweets .

In some countries, radiologists are directly involved in disease surveillance programs e.g. hepatocellular carcinoma surveillance.

NB: The term surveillance is often, but not always, used differently in radiology reports to imply the follow up of a pathological finding.