1.      A patient is treated on the 6-MV linear accelerator…

1.      A patient is treated on the 6-MV linear accelerator at 100 cm SSD. The collimator setting is 13 x 13 cm. The MLC reduces the treated area to a 9 x 9 cm EFS. The prescription states that a dose of 6500 cGy is to be delivered to a depth of 14 cm in 25 fractions using an AP/PA treatment field arrangement. The patient’s central axis separation is 28 cm. The spinal cord lies 5.0 cm beneath the posterior skin surface. Calculate the total Dmax dose and the cord dose.