CPB Ljubljana 2018 course book

Equivalent active length

(To have the same dose distribution)

Active length

5 cm

Equivalent active length

EAL= n (sources) x s

5 cm

For 11 activated sources (5 cm activation):

5,5 cm

EAL = 11 x 0.5 = 5.5 cm

Treated length for 5,5 cm EAL  5.5 x 0,7 = 3,85

3,85 / 5 (AL) ≈ 0,8