Erratum: “Recommendations for clinical electron beam dosimetry: Supplement tothe recommendations of Task Group 25” [Med. Phys. 36, 3239–3279(2009)]

Calculating Req based on either Ē0 or Ep,0 gives very similar values. There is very little difference in the calculated value of Req using either Ē0 or Ep,0, and the difference is between 0.5 and 1.5 mm for the most common clinical electron energies. The use of Ep,0 produces slightly larger values of Req, the minimum radius of a circular field required for lateral scatter equilibrium. We recommend using the original equation from the historical literature based on Ep,0.