Result: For the 6MV-WFF beam, differences in values of HI, CQ, CN, and Dmean between AXB and sAXB were within 2.5% 14%, 3.6% 14.9%, - 9.5% - 59.5% and 3.0% 14% by reducing the target volume diameter of the phantom from 4 cm down to 0.5 cm.