Выражение встречается в следующем контексте:

Every production batch of "BrachySeed" sources is swipe tested by Quality Control for radioactive contamination.

Заранее спасибо

A procedure in which a swab, e.g., a circle of filter paper, is rubbed on a surface and its radioactivity measured to determine if the surface is contaminated with loose radioactive material.

http://www.susqu.edu/facstaff/r/richard/SU R Safety manual.HTML