Avaliação dosimétrica de erros de posicionamento para implementação da técnica de neuroeixo com arcoterapia volumétrica modulada (VMAT)

Authors

  • Henrique Carvalhinho Büll Beneficencia Portuguesa São Paulo
  • Mario Ribeiro Neto
  • Carlos Eduardo Bravin Maistro
  • Hélio Yoriyaz
  • Caroline Castilhano Sampaio

DOI:

https://doi.org/10.29384/rbfm.2023.v17.19849001649

Keywords:

física médica, radioterapia, irradiação de neuroeixo, arcoterapia, VMAT, intensidade modulada

Abstract

Retrospectively evaluated corrections of planar images of patients already submitted to craniospinal irradiation (CSI) treatments, in order to quantify setup errors magnitude and simulate them in different volumetric modulated arc therapy (VMAT) plans to define the one with the lowest dosimetric impact for implementation in clinical practice.

219 planar images of 15 patients previously treated were selected for statistical evaluation of positional errors. For VMAT plans, four pediatric patients who completed treatment with 3D conformational technique were selected and five VMAT plans were optimized in two different techniques: "overlap" with 3 cm, 6 cm and 9 cm of junction and "gradient" with 6 cm and 9 cm. The plans were evaluated by V100%, V95%, D98%, D2%, conformity number (CN) and heterogeneity index (HI). In each, setup errors with the magnitude found from the retrospective analysis were used to shift the isocenter in the longitudinal direction, in order to assess the dosimetric impact the errors, as well as to evaluated the difference in dose distribution when considering the treatment couch.

The analysis of the images showed average displacements between 1 and 5 mm and in some cases reaching a maximum of 15 mm. Regarding the quality of the plans, all obtained consistent results based on the metrics without significant differences between them. However, the smooth gradient technique (9 cm of junction) obtained a lower dosimetric impact when compared to others when subjected to positional errors. Finally, when considering the treatment couch in the planning, a reduction of 10% was found in the V100%.

The implementation of the VMAT for CSI, it’s recommended daily positioning image to minimize setup errors with magnitudes greater than the average of 3 mm, as these have a significant impact on the dose distribution in the modulated plans.

Downloads

Download data is not yet available.

References

Van Dyk J, Jenkin RD, Leung PM, et al. Medulloblastoma: Treatment technique and radiation dosimetry. Int J Radiat Oncol Biol Phys. 1977;2:993–1005.

Liu AK, Thornton D, Backus J, Dzingle W, Stoehr S, Newman F. Supine Craniospinal Irradiation Setup with Two Spine Fields. Medical Dosimetry. 2009;34(3):214–6.

Parker WA, Freeman CR. A simple technique for craniospinal radiotherapy in the supine position. Radiotherapy and Oncology. 2006;78(2):217–22.

Neelakandan V, Christy Ss, Mukherji A, Reddy Ks. Craniospinal irradiation by rapid Arc ® technique in supine position: A dosimetric and clinical analysis. J Curr Oncol. 2018;1(1):16.

Studenski MT, Shen X, Yu Y, Xiao Y, Shi W, Biswas T, et al. Intensity-modulated radiation therapy and volumetric-modulated arc therapy for adult craniospinal irradiation—A comparison with traditional techniques. Medical Dosimetry. 2013;38(1):48–54.

Strojnik A, Méndez I, Peterlin P. Reducing the dosimetric impact of positional errors in field junctions for craniospinal irradiation using VMAT. Reports of Practical Oncology & Radiotherapy. 2016;21(3):232–9.

Myers P, Stathakis S, Mavroidis P, Esquivel C, Papanikolaou N. Evaluation of localization errors for craniospinal axis irradiation delivery using volume modulated arc therapy and proposal of a technique to minimize such errors. Radiotherapy and Oncology. 2013;108(1):107–13.

Traneus E, Bizzocchi N, Fellin F, Rombi B, Farace P. Universal field matching in craniospinal irradiation by a background-dose gradient-optimized method. J Appl Clin Med Phys. 2018;19(1):46–9

Wang K, Meng H, Chen J, Zhang W, Feng Y. Plan quality and robustness in field junction region for craniospinal irradiation with VMAT. Physica Medica 2018;48:21–6.

Chen J, Chen C, Atwood TF, Gibbs IC, Soltys SG, Fasola C, et al. Volumetric modulated arc therapy planning method for supine craniospinal irradiation. J Radiat Oncol. 2012;(3):291–7.

Zhou Y, Ai Y, Han C, Zheng X, Yi J, Xie C, et al. Impact of setup errors on multi-isocenter volumetric modulated arc therapy for craniospinal irradiation. Journal of Applied Clinical Medical Physics. 2020;21(11):115–23.

Introduction of Image Guided Radiotherapy into Clinical Practice [Internet]. IAEA; 2019 [cited 2021 Feb 20]. Available from: https://www.iaea.org/publications/12264/introduction-of-image-guided-radiotherapy-into-clinical-practice

Feuvret L, Noel G, Mazeron JJ, Bey P. Conformity index: a review. Int J Radiat Oncol Biol Phys 2006;64:333–42.

ICRU Report 83, Prescribing, Recording, and Reporting Intensity-Modulated Photon-Beam Therapy (IMRT). International Commission on Radiation Units and Measurements (ICRU) 2022.

Li H, Lee AK, Johnson JL, Zhu RX, Kudchadker RJ. Characterization of dose impact on IMRT and VMAT from couch attenuation for two Varian couches. J Appl Clin Med Phys. 2011 Mar 2;12(3):3471. doi: 10.1120/jacmp.v12i3.3471. PMID: 21844859; PMCID: PMC5718645.

Zhang R, Gao Y, Bai W. Quantification and comparison the dosimetric impact of two treatment couch model in VMAT. J Appl Clin Med Phys. 2018 Jan;19(1):10-16. doi: 10.1002/acm2.12206. Epub 2017 Nov 2. PMID: 29094802; PMCID: PMC5768035.

Published

2023-04-03

How to Cite

Carvalhinho Büll, H., Ribeiro Neto, M., Bravin Maistro, C. E., Yoriyaz, H., & Castilhano Sampaio, C. (2023). Avaliação dosimétrica de erros de posicionamento para implementação da técnica de neuroeixo com arcoterapia volumétrica modulada (VMAT). Brazilian Journal of Medical Physics, 17, 649. https://doi.org/10.29384/rbfm.2023.v17.19849001649

Issue

Section

Artigo Original

Most read articles by the same author(s)

1 2 > >>