Background: The photon dose calculation model anisotropic analytical algorithm (AAA) available with eclipse integrated treatment planning system (TPS) (Varian) supports telecobalt dose calculation from Version 13. 6 onward. Formerly. pencil beam convolution (PBC) was used for modeling telecobalt machines. https://www.roneverhart.com/HP-Notebook-15-da0008ca-HD-LED-15-6-Touchscreen-Intel-Core-i5-8250U-1-6-GHz-8-GB-RAM-1-TB-SSD-HDMI-USB-Multi-format-S/