Iranian Journal of Medical Physics

Iranian Journal of Medical Physics

Implementation of Aperture-Based Complexity Metrics of MLC Opening based on the IMRT Technique for Central Nervous System (CNS) and Breast cases

Document Type : Original Paper

Authors
Meirisa Ambalinggi 1
Aloysius Mario Yudi Putranto 2
Dewa Ngurah Yudhi Prasada 2
Ida Ayu Putu Inten Gayatri 2
Supriyanto Ardjo Pawiro 1
Dwi Seno Kuncoro Sihono 1
1 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia
2 Department of Radiation Oncology, Mochtar Riady Comprehensive Cancer Center (MRCCC) Siloam Hospital Semanggi, Jakarta
10.22038/ijmp.2023.69437.2226
Abstract
Introduction: Complexity metrics have been suggested to characterize treatment plans based on machine parameters such as multileaf collimator (MLC) position. Several complexity metrics have been proposed and related to the Intensity-modulated radiation therapy (IMRT) quality assurance results. This study aims to evaluate aperture-based complexity metrics on MLC openings used in clinicaland establish a correlation between plan complexity and the gamma passing rate (GPR) for the IMRT plans.
Material and Methods: We implemented the aperture-based complexity metric on MLC openings of the IMRT treatment plan for breast  and central nervous system (CNS) cases . The modulation complexity score (MCS), the edge area metric (EAM), the converted area metric (CAM), the circumference/area (CPA), and the ratio monitor unit MU/Gy are evaluated in this study. The complexity score was calculated using Matlab. The MatriXX Evolution was used for dose verification. The dose distribution was  analyzed using the OmniPro-I'mRT program  and the gamma index was assessed using two criteria: 3%/3 mm and 3%/2 mm. The correlation between the calculated complexity score and the GPR  is analyzed using SPSS.
Results: The complexity score calculated by MCS, EAM, CAM, CPA, and MU/Gy shows breast plan is more complex than the CNS plan. The results of the correlation test of the complexity metric and GPR show that only the EAM metric shows a good correlation with GPR for both cases.
Conclusion: EAM strongly correlates with the gamma pass rate. The MCS, CAM, CPA, and MU/Gy have a weak correlation with the GPR.
Keywords
Radiotherapy Intensity
Modulated Central Nervous System Radiotherapy Planning
Subjects

 

 

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Iranian Journal of Medical Physics
Volume 21, Issue 2
March and April 2024
Pages 71-77

  • Receive Date 09 December 2022
  • Revise Date 20 May 2024
  • Accept Date 15 March 2023