Evaluation and Comparison of AAA and AXB Dose Calculation Algorithms for Lung SBRT on TrueBeam STx with Eclipse 13.6

Pham Hong Lam1,2, Phan Tien Dung3, Vu Phuong Quy4, Pham Quang Trung5,6
1 Military Hospital 103
2 Graduate University of Science and Technology, Viet Nam Academy of Science and Technology (VAST)
3 Institute of Material Sciences, Viet Nam Academy of Science and Technology (VAST)
4 School of Engineering Physics, Ha Noi University of Sciences and Technology
5 108 Military Central Hospital
6 Radiation Oncology and Radiosurgery Department

Main Article Content


This study aims to comprehensively evaluate and compare lung Stereotactic Body Radiation Therapy (SBRT) dose distribution using the Eclipse v13.6 treatment planning system and TrueBeam STx linac data, employing two dose calculation algorithms: Analytical Anisotropic Algorithm (AAA) and Acuros External Beam (AXB). Utilizing thirty-five 4DCT lung SBRT datasets, dose calculations were performed with both algorithms, maintaining consistent setup conditions except for the varied calculation algorithm. Evaluation criteria included tumor dose distribution Conformity Index (CI), Homogeneity Index (HI), Gradient Index (GI), D2cm, V105%, Dmax and organs-at-risk (OAR) doses, assessed via Dose Volume Histogram (DVH) analysis. Additionally, linac parameters such as Monitor Unit (MU) and Beam on Time (BoT) were analyzed. Both algorithms met dose criteria for tumors and OAR tolerance. Minor differences were observed in tumor distribution indices, with AXB's Gradient Index showing proximity to ideal values. Although AXB exhibited slightly higher OAR doses, differences were statistically insignificant. AXB also demonstrated reduced average MUs and BoT. This comparative analysis underscores the efficacy of both AAA and AXB algorithms in ensuring dose conformity and OAR tolerance in lung SBRT planning, with AXB potentially offering improvements in efficiency and patient safety.

Article Details


[1]. GLOBOCAN. https://gco.iarc.who.int/. 2022.
[2]. Benedict, S.H., et al., Stereotactic body radiation therapy: the report of AAPM Task Group 101. Medical physics, 2010. 37(8): p. 4078-4101.
[3]. Gao, J. and X. Liu, Winston-Lutz-Gao test on the true beam STx linear accelerator. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 2019. 8(1): p. 9-20.
[4]. Mani, K.R., et al., Open beam dosimetric characteristics of True Beam medical linear accelerator with flattening filter (WFF) and flattening filter free (FFF) beam. Polish Journal of Medical Physics and Engineering, 2018. 24(2): p. 79-89.
[5]. Sarin, B., et al., Dosimetric accuracy of Acuros® XB and AAA algorithms for stereotactic body radiotherapy (SBRT) lung treatments: evaluation with PRIMO Monte Carlo code. Journal of Radiotherapy in Practice, 2023. 22: p. e65.
[6]. Tsuruta, Y., et al., Dosimetric comparison of Acuros XB, AAA, and XVMC in stereotactic body radiotherapy for lung cancer. Medical physics, 2014. 41(8Part1): p. 081715.
[7]. Huang, B., et al., Dose calculation of Acuros XB and Anisotropic Analytical Algorithm in lung stereotactic body radiotherapy treatment with flattening filter free beams and the potential role of calculation grid size. Radiation oncology, 2015. 10: p. 1-8.
[8]. Sievinen, J., W. Ulmer, and W. Kaissl, AAA photon dose calculation model in Eclipse. Palo Alto (CA): Varian Medical Systems, 2005. 118: p. 2894.
[9]. Chen, W.-Z., Y. Xiao, and J. Li, Impact of dose calculation algorithm on radiation therapy. World journal of radiology, 2014. 6(11): p. 874.
[10]. Failla, G.A., et al., Acuros XB advanced dose calculation for the Eclipse treatment planning system. Palo Alto, CA: Varian Medical Systems, 2010. 20: p. 18.
[11]. Fogliata, A. and L. Cozzi, Dose calculation algorithm accuracy for small fields in non-homogeneous media: The lung SBRT case. Physica Medica, 2017. 44: p. 157-162.
[12]. Videtic, G.M., et al., Long-term follow-up on NRG oncology RTOG 0915 (NCCTG N0927): a randomized phase 2 study comparing 2 stereotactic body radiation therapy schedules for medically inoperable patients with stage I peripheral non-small cell lung cancer. International Journal of Radiation Oncology* Biology* Physics, 2019. 103(5): p. 1077-1084.
[13]. Bezjak, A., et al., Safety and efficacy of a five-fraction stereotactic body radiotherapy schedule for centrally located non–small-cell lung cancer: NRG oncology/RTOG 0813 trial. Journal of Clinical Oncology, 2019. 37(15): p. 1316.
[14]. Shaw, E., et al., Radiation Therapy Oncology Group: radiosurgery quality assurance guidelines. International Journal of Radiation Oncology* Biology* Physics, 1993. 27(5): p. 1231-1239.
[15]. Davis, J.N., et al., Stereotactic body radiotherapy for early-stage non-small cell lung cancer: clinical outcomes from a National Patient Registry. Journal of Radiation Oncology, 2015. 4: p. 55-63.
[16]. Paddick, I. and B. Lippitz, A simple dose gradient measurement tool to complement the conformity index. Journal of neurosurgery, 2006. 105(Supplement): p. 194-201.
[17]. Wu, Q. and R. Mohan, Algorithms and functionality of an intensity modulated radiotherapy optimization system. Medical physics, 2000. 27(4): p. 701-711.
[18]. Hoffman, D., et al., Lung Stereotactic Body Radiation Therapy (SBRT) dose gradient and PTV volume: a retrospective multi-center analysis. Radiation Oncology, 2019. 14: p. 1-7.