Background: This study was to investigate the dose variation between anisotropic analytical algorithm (AAA) and Acuros XB (AXB) calculation algorithms in heterogeneous inside planning target volume (PTV) of pituitary carcinoma.Methods: AAA and AXB algorithms were used for dose calculation by Eclipse treatment planning system in Varian TrueBeam linear accelerator machine with 120 MLC. Twelve cases of pituitary carcinoma were planned by intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)techniques. The target overlapped with the air cavity. IMRT plans were done by 9 static fields and VMAT plans were done by 2-3 arc rotation fields. The PTV was prescribed the dose of 50.4 Gy. The dosimetry was analyzed by dose to 95% and 98% of volume of PTV, maximum dose, dose coverage, and conformity index (CI) of PTV. The normal organ was analyzed by mean dose (Dmean) and maximum dose (Dmax). Results:The dose coverage of PTV using AXB calculation was less than using AAA calculation in the air cavity region for both IMRT and VMAT. The dose coverage of PTV was any statistical significantly difference between AAA and AXB algorithms. For the normal organs, the mean and maximum dose agreed well for AAA and AXB algorithms.Conclusions: AXB can calculate the dose more accurate than AAA for dose calculation in inhomogeneous region. AXB algorithms should be selected for dose calculation in clinical.