Rx = 3000 cGy in 10 fractions, whole brain Rt and Lt laterals, KD Siemens 6x. The collimator is set for 22 X 16 cm2 portal films at 92.5 cm SSD. Calculate the treatment port MU to isocenter. Calibration performed std. SAD; treatment performed SSD (assume SSDs at the calc point = 92.5 cm).