An active polaron scan was a type of polaron scan used by Jem'Hadar starships.
In 2373, a Jem'Hadar patrol ship on a reconnaissance mission used an active polaron scan on a sector of the Alpha Quadrant beyond the Cardassian border. The IKS Rotarran, which was cloaked at the time, remained undetected, and Jadzia Dax hypothesized that they stood less than a three percent chance of being detected by the scan. (DS9: "Soldiers of the Empire")