Non-destructive testing (NDT) refers to the process of inspecting objects without making them unfit for the purpose they are designed for; hence non-destructive. In contrast, “destructive” processes, also referred to as lot-sampling, destroy the sample when testing it. Hence, NDT is usually integrated within production processes and aims at testing large percentages of production units to ensure product integrity and reliability, control manufacturing processes, lower production costs and to maintain a uniform quality level.

Scanning and imaging for medical and security applications have similar requirements of not harming the person examined or destroying the object tested. However, NDT comes in different application spaces and hence classified differently.