Page 81 - ARNM-2-4

Advances in Radiotherapy &

Nuclear Medicine

SHORT COMMUNICATION
Simulated study relating dose-volume

histogram metrics to three-dimensional gamma
analysis results

2
1
Larisse Neumann Bonatto¹, Alexandre Colello Bruno , Oswaldo Baffa * ,
and Juliana Fernandes Pavoni 1,2
1 Department of Radiotherapy, Ribeirão Preto Medical School Hospital and Clinics, University of São
Paulo, Av. Bandeirantes, Monte Alegre, Ribeirão Preto, São Paulo, Brazil
2 Department of Physics, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São
Paulo, Av. Bandeirantes, Monte Alegre, Ribeirão Preto, São Paulo, Brazil

Abstract
This study aims to investigate the relationship between the three-dimensional
gamma index (3DGI) results and its clinical significance, proposing a correlation
between changes in dose values in the dose-volume histogram (DVH) of the
evaluated structures and 3DGI percentages of approval. In this study, we created 30
plans by including 1 mm displacement errors in the lateral, vertical, and longitudinal
axes of each table, and compared them to a simulated, error-free treatment plan
for prostate cancer. The plans were made in a commercial treatment planning
system, using 6MV Varian 120-leaf multileaf collimators (MLC) linear accelerators
*Corresponding author: and intensity modulated radiation therapy sliding window technique. We used a
Oswaldo Baffa calculation algorithm-based MATLAB programming to evaluate the 3DGI analysis of
(baffa@usp.br) fluence maps. The acceptance criteria were 3%/2 mm, 10% dose threshold, and 95%
Citation: Bonatto LN, Bruno AC, gamma passing rate. We compared 3DGI results with differences in structures DVH.
Baffa O, Pavoni JF. Simulated DVH metrics versus 3DGI analysis showed a correlation between the percentage of
study relating dose-volume
histogram metrics to three- point’s approval and planning target volume (PTV) coverage, presenting a degree of
dimensional gamma analysis agreement of 0.85%, 0.96%, and 0.94% in the longitudinal, lateral, and vertical axes,
results. Adv Radiother Nucl Med. respectively. In summary, it was possible to establish a linear relationship between
2024;2(4):4005.
doi: 10.36922/arnm.4005 the percentage of points approved in the 3DGI analysis and the PTV dose. A similar
behavior was also observed in bladder and rectum DVH, but for these structures, the
Received: June 21, 2024
relationship was not the same in the three displaced axes.
Accepted: October 11, 2024
Published Online: November 13, Keywords: 3D gamma index; Radiotherapy; Fluence maps; Intensity-modulated
2024
radiation therapy; Quality assurance
Copyright: © 2024 Author(s).
This is an Open-Access article
distributed under the terms of the
Creative Commons Attribution
License, permitting distribution, 1. Introduction
and reproduction in any medium,
provided the original work is According to the 2022 global incidence of cancer, prostate cancer is projected to be the
properly cited. second most common cancer in men, with approximately 1,467,000 new cases being
Publisher’s Note: AccScience estimated, equivalent to 7.8% of the total new cases, excluding non-melanoma skin
Publishing remains neutral with tumors. Despite the high prevalence, the 5-year survival rate of patients with localized
1
regard to jurisdictional claims in 2
published maps and institutional prostate cancer is 100%. According to the most recent National Comprehensive Cancer
affiliations Network guidelines, external beam radiation therapy should be used in the management

Volume 2 Issue 4 (2024) 1 doi: 10.36922/arnm.4005