Dose Accuracy Improvement on Head and Neck VMAT Treatments by Using the Acuros Algorithm and Accurate FFF Beam Calibration

Overview

Journal Rep Pract Oncol Radiother

Specialty Oncology

Date 2021 May 5

PMID 33948305

Citations 1

Authors

Guadalupe Martin-Martin

Stefan Walter

Eduardo Guibelalde

Affiliations

Soon will be listed here.

Abstract

Background: The purpose of this study was to assess dose accuracy improvement and dosimetric impact of switching from the anisotropic analytical algorithm (AA) to the Acuros XB algorithm (AXB) when performing an accurate beam calibration in head and neck (H&N) FFF-VMAT treatments.

Materials And Methods: Twenty H&N cancer patients treated with FFF-VMAT techniques were included. Calculations were performed with the AA and AXB algorithm (dose-to-water - AXB- and dose-to-medium - AXB-). An accurate beam calibration was used for AXB calculations. Dose prescription to the tumour (PTV70) and at-risk-nodal region (PTV58.1) were 70 Gy and 58.1 Gy, respectively. A PTV70 including bony structures in PTV70 was contoured. Dose-volume parameters were compared between the algorithms. Statistical tests were used to analyze the differences in mean values and the correlation between compliance with the D95 > 95% requirement and occurrence of local recurrence.

Results: AA systematically overestimated the dose compared to AXB algorithm with mean dose differences within 1.3 Gy/2%, except for the PTV70 (2.2 Gy/3.2%). Dose differences were significantly higher for AXB calculations when including accurate beam calibration (maximum dose differences up to 2.8 Gy/4.1% and 4.2 Gy/6.3% for PTV70 and PTV70, respectively). 80% of AA-calculated plans did not meet the D95 > 95% requirement after recalculation with AXB and accurate beam calibration. The reduction in D95 coverage in the tumour was not clinically relevant.

Conclusions: Using the AXB algorithm and carefully reviewing the beam calibration procedure in H&N FFF-VMAT treatments ensures (1) dose accuracy increase by approximately 3%; (2) a consequent dose increase in targets; and (3) a dose reporting mode that is consistent with the trend of current algorithms.

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References

Munoz-Montplet C, Marruecos J, Buxo M, Jurado-Bruggeman D, Romera-Martinez I, Bueno M . Dosimetric impact of Acuros XB dose-to-water and dose-to-medium reporting modes on VMAT planning for head and neck cancer. Phys Med. 2018; 55:107-115. DOI: 10.1016/j.ejmp.2018.10.024. View

Kan M, Leung L, So R, Yu P . Experimental verification of the Acuros XB and AAA dose calculation adjacent to heterogeneous media for IMRT and RapidArc of nasopharygeal carcinoma. Med Phys. 2013; 40(3):031714. DOI: 10.1118/1.4792308. View

Hirata K, Nakamura M, Yoshimura M, Mukumoto N, Nakata M, Ito H . Dosimetric evaluation of the Acuros XB algorithm for a 4 MV photon beam in head and neck intensity-modulated radiation therapy. J Appl Clin Med Phys. 2015; 16(4):52–64. PMC: 5690026. DOI: 10.1120/jacmp.v16i4.5222. View

Vargas Castrillon S, Cutanda Henriquez F . Choice of a Suitable Dosimeter for Photon Percentage Depth Dose Measurements in Flattening Filter-Free Beams. J Med Phys. 2017; 42(3):140-143. PMC: 5618460. DOI: 10.4103/jmp.JMP_11_17. View

Kathirvel M, Subramanian S, Clivio A, Arun G, Fogliata A, Nicolini G . Critical appraisal of the accuracy of Acuros-XB and Anisotropic Analytical Algorithm compared to measurement and calculations with the compass system in the delivery of RapidArc clinical plans. Radiat Oncol. 2013; 8:140. PMC: 3702450. DOI: 10.1186/1748-717X-8-140. View

OBRIEN P, Gillies B, Schwartz M, Young C, Davey P . Radiosurgery with unflattened 6-MV photon beams. Med Phys. 1991; 18(3):519-21. DOI: 10.1118/1.596656. View

Fogliata A, Vanetti E, Albers D, Brink C, Clivio A, Knoos T . On the dosimetric behaviour of photon dose calculation algorithms in the presence of simple geometric heterogeneities: comparison with Monte Carlo calculations. Phys Med Biol. 2007; 52(5):1363-85. DOI: 10.1088/0031-9155/52/5/011. View

Han T, Mikell J, Salehpour M, Mourtada F . Dosimetric comparison of Acuros XB deterministic radiation transport method with Monte Carlo and model-based convolution methods in heterogeneous media. Med Phys. 2011; 38(5):2651-64. PMC: 3107831. DOI: 10.1118/1.3582690. View

Hyun M, Miller J, Micka J, DeWerd L . Ion recombination and polarity corrections for small-volume ionization chambers in high-dose-rate, flattening-filter-free pulsed photon beams. Med Phys. 2016; 44(2):618-627. DOI: 10.1002/mp.12053. View

10.

Bush K, Gagne I, Zavgorodni S, Ansbacher W, Beckham W . Dosimetric validation of Acuros XB with Monte Carlo methods for photon dose calculations. Med Phys. 2011; 38(4):2208-21. DOI: 10.1118/1.3567146. View

11.

Cashmore J . The characterization of unflattened photon beams from a 6 MV linear accelerator. Phys Med Biol. 2008; 53(7):1933-46. DOI: 10.1088/0031-9155/53/7/009. View

12.

Chetty I, Curran B, Cygler J, DeMarco J, Ezzell G, Faddegon B . Report of the AAPM Task Group No. 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning. Med Phys. 2008; 34(12):4818-53. DOI: 10.1118/1.2795842. View

13.

Kry S, Feygelman V, Balter P, Knoos T, Ma C, Snyder M . AAPM Task Group 329: Reference dose specification for dose calculations: Dose-to-water or dose-to-muscle?. Med Phys. 2019; 47(3):e52-e64. DOI: 10.1002/mp.13995. View

14.

Han T, Mourtada F, Kisling K, Mikell J, Followill D, Howell R . Experimental validation of deterministic Acuros XB algorithm for IMRT and VMAT dose calculations with the Radiological Physics Center's head and neck phantom. Med Phys. 2012; 39(4):2193-202. PMC: 3337663. DOI: 10.1118/1.3692180. View

15.

Kry S, Popple R, Molineu A, Followill D . Ion recombination correction factors (P(ion)) for Varian TrueBeam high-dose-rate therapy beams. J Appl Clin Med Phys. 2012; 13(6):3803. PMC: 5718527. DOI: 10.1120/jacmp.v13i6.3803. View

16.

Kan M, Leung L, Yu P . Dosimetric impact of using the Acuros XB algorithm for intensity modulated radiation therapy and RapidArc planning in nasopharyngeal carcinomas. Int J Radiat Oncol Biol Phys. 2012; 85(1):e73-80. DOI: 10.1016/j.ijrobp.2012.08.031. View

17.

Vassiliev O, Wareing T, McGhee J, Failla G, Salehpour M, Mourtada F . Validation of a new grid-based Boltzmann equation solver for dose calculation in radiotherapy with photon beams. Phys Med Biol. 2010; 55(3):581-98. DOI: 10.1088/0031-9155/55/3/002. View

18.

Ojala J, Kapanen M, Hyodynmaa S, Wigren T, Pitkanen M . Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo-based dose distributions. J Appl Clin Med Phys. 2014; 15(2):4662. PMC: 5875463. DOI: 10.1120/jacmp.v15i2.4662. View

19.

Corns R, Huang V, Thomas S . Pion effects in flattening filter-free radiation beams. J Appl Clin Med Phys. 2015; 16(6):376–385. PMC: 5691018. DOI: 10.1120/jacmp.v16i6.5869. View

20.

Muralidhar K, Pangam S, Srinivas P, Ali M, Priya V, Komanduri K . A phantom study on the behavior of Acuros XB algorithm in flattening filter free photon beams. J Med Phys. 2015; 40(3):144-9. PMC: 4594383. DOI: 10.4103/0971-6203.165076. View