Efficacy of flattening filter-free beams with the acuros XB algorithm in thoracic spine stereotactic body radiation therapy

Islam Tarek; Abdelrahman Hafez; Mohamed M Fathy; Heba M Fahmy; Dina M Abdelaziz

doi:10.1016/j.meddos.2024.01.005

Efficacy of flattening filter-free beams with the acuros XB algorithm in thoracic spine stereotactic body radiation therapy

Med Dosim. 2024 Feb 8:S0958-3947(24)00005-0. doi: 10.1016/j.meddos.2024.01.005. Online ahead of print.

Authors

Islam Tarek¹, Abdelrahman Hafez², Mohamed M Fathy³, Heba M Fahmy⁴, Dina M Abdelaziz⁵

Affiliations

¹ Department of Biophysics, Faculty of Science, Cairo University, Cairo, Egypt; Department of Radiotherapy, Baheya center for early detection and treatment of breast cancer, Giza, Egypt. Electronic address: islam.tm26@gmail.com.
² Department of Radiotherapy, Baheya center for early detection and treatment of breast cancer, Giza, Egypt.
³ Department of Biophysics, Faculty of Science, Cairo University, Cairo, Egypt. Electronic address: mfathy@sci.cu.edu.eg.
⁴ Department of Biophysics, Faculty of Science, Cairo University, Cairo, Egypt.
⁵ Department of Radiotherapy, Baheya center for early detection and treatment of breast cancer, Giza, Egypt; Department of Radiotherapy, National cancer institute, Cairo University, Cairo, Egypt.

PMID: 38336567
DOI: 10.1016/j.meddos.2024.01.005

Abstract

This study aimed to determine the dosimetric value of flattening filter-free (FFF) beams compared to flattening filter (FF) beams using different algorithms in the treatment planning of thoracic spine stereotactic body radiation therapy (SBRT). A total of 120 plans were created for 15 patients using the Anisotropic Analytical Algorithm (AAA) and the Acuros External Beam (AXB) algorithm with FF and FFF beams at 6 MV and 10 MV energies. Various dosimetric parameters were evaluated, including target coverage, dose spillage, and organs-at-risk sparing of the spinal cord and esophagus. Treatment delivery parameters, such as the monitor units (MUs), modulation factors (MFs), beam-on time (BOT), and dose calculation time (DCT), were also collected. Significant differences were observed in the dosimetric parameters when AXB was used for all energies (P < 0.05). 6 XFFF energy was the best option for target coverage, dose spillage, and organs-at-risk sparing. In contrast, dosimetric parameters had no significant difference when using the AAA. The AAA and AXB calculations showed that the 6 XFFF beam had the shortest DCT. The treatment delivery parameters indicated that 10 XFF beam required the fewest MUs and MFs. In addition, the 10 XFFF beam demonstrated the shortest BOT. For effective treatment of the thoracic spine using SBRT, it is recommended to use the 10 XFFF beam because of the short BOT. Moreover, the AXB algorithm should be used because of its accurate dose calculation in regions with tissue heterogeneity.

Keywords: Acuros external beam; Anisotropic analytical algorithm; Flattening filter free beams; Stereotactic body radiotherapy; Thoracic spine tumors.