Nurhadi, I., Ramdani, R., Haryanto, F., Perkasa, Y. and Sanjaya, M. 2019. Analysis of Effect of Change Source to Surface Distance (SSD) and the Field Size to Distribution Dose Using Monte Carlo Method-EGSnrc. Indonesian Journal of Physics. 30, 1 (Jan. 2019), 14 - 17. DOI:https://doi.org/10.5614/itb.ijp.2019.30.1.3.