A patient is treated on a 6-MV machine at 100 cm SSD.The collimator setting is 15 x 15.There is no blocking used for this treatment.The prescription states that a dose of 3000 cGy is to be delivered to a depth of 3 cm in 10 fractions using a posterior treatment field using the nonisocentric method of calculation.The patient central axis separation is 20 cm.What is the MU setting for the treatment? Reference dose rate (RDR)for a 15 cm equivalent square is 0.993 cGy/MU.

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The equivalent square is 15 cm.The daily dose is 300 cGy/day.The PDD for a 6-MV beam at 3 cm for 15-cm equivalent square is 95.2%.The RDR is 0.993 cGy/MU.
MU setting = --------------------------

A Patient Is Treated on a 6-MV Machine at 100