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Research paper (original)
Published online: 2024-01-04
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Comparison of EPID portal dosimetry verification and RadCalc dose verification for VMAT treatment plans

Adam Gądek1, Dominika Plaza1, Łukasz Sroka1, Marta Reudelsdorf-Ullmann1, Krzysztof Ślosarek1
Affiliations
  1. Radiotherapy Planning Department, Maria Sklodowska-Curie National Research Institute, Gliwice Branch, Gliwice, Poland

open access

Ahead of print
Original articles – Radiotherapy
Published online: 2024-01-04

Abstract

Introduction. Dosimetry verification is required before starting each treatment. The legal regulations does not clearly define one method of plan verification. Therefore it is allowed to perform measurements (electronic portal imaging device [EPID]) or calculations using an independent system. Portal dosimetry using EPID matrices was compared with the RadCalcTM system v. 7.1.4.1, performing independent dose distribution calculations.

Materials and methods. Treatment plans were made for 150 patients treated with the photon 6MV VMAT technique. Three groups of patients were studied: those treated for breast cancer, those treated for prostate cancer and those irradiated to the prostate area with nodes. Then, the dosimetry verification was carried out on the accelerator using the EPID portal and compared with the independent RadCalc software calculation results.

Results. Comparison of tumor proportion score (TPS) vs. EPID and vs. RC calculations for breast, prostate, and prostate with nodes showed no significant statistical differences. Regardless of the size (volume) of the clinical target volume (CTV) area, no significant difference was observed, although there was a greater agreement for large CTVs compared to small ones. Similarly, there was no significant difference in the compared methods based on depth, but there was a better agreement for small depths than large ones.

Conclusions. Verification methods in the study groups showed compliance of the measured (EPID) and calculated (RadCalc) doses with the values planned in the TPS. This confirms that verification for patients treated with radiotherapy can be performed with any of these methods. However, for radiosurgical techniques, it is better to use the EPID method because the RadCalc method may give false negative results.

Abstract

Introduction. Dosimetry verification is required before starting each treatment. The legal regulations does not clearly define one method of plan verification. Therefore it is allowed to perform measurements (electronic portal imaging device [EPID]) or calculations using an independent system. Portal dosimetry using EPID matrices was compared with the RadCalcTM system v. 7.1.4.1, performing independent dose distribution calculations.

Materials and methods. Treatment plans were made for 150 patients treated with the photon 6MV VMAT technique. Three groups of patients were studied: those treated for breast cancer, those treated for prostate cancer and those irradiated to the prostate area with nodes. Then, the dosimetry verification was carried out on the accelerator using the EPID portal and compared with the independent RadCalc software calculation results.

Results. Comparison of tumor proportion score (TPS) vs. EPID and vs. RC calculations for breast, prostate, and prostate with nodes showed no significant statistical differences. Regardless of the size (volume) of the clinical target volume (CTV) area, no significant difference was observed, although there was a greater agreement for large CTVs compared to small ones. Similarly, there was no significant difference in the compared methods based on depth, but there was a better agreement for small depths than large ones.

Conclusions. Verification methods in the study groups showed compliance of the measured (EPID) and calculated (RadCalc) doses with the values planned in the TPS. This confirms that verification for patients treated with radiotherapy can be performed with any of these methods. However, for radiosurgical techniques, it is better to use the EPID method because the RadCalc method may give false negative results.

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Keywords

verification; electronic portal imaging device; RadCalc

About this article
Title

Comparison of EPID portal dosimetry verification and RadCalc dose verification for VMAT treatment plans

Journal

Nowotwory. Journal of Oncology

Issue

Ahead of print

Article type

Research paper (original)

Published online

2024-01-04

Page views

69

Article views/downloads

44

DOI

10.5603/njo.97697

Keywords

verification
electronic portal imaging device
RadCalc

Authors

Adam Gądek
Dominika Plaza
Łukasz Sroka
Marta Reudelsdorf-Ullmann
Krzysztof Ślosarek

References (13)
  1. Ślosarek K, Gądek A, Reudelsdorf-Ullmann M, et al. The prototype of EPID-based in vivo dose verification for VMAT treatments in patients with prostate cancer. NOWOTWORY Journal of Oncology. 2023; 73(1): 10–17.
  2. Radwan M, Grządziel A, Hawrylewicz L, et al. Wpływ energii wiązek fotonowych na rozkład dawek dla planów IMRT i VMAT. Nowotwory. Journal of Oncology. 2014; 64(3): 230–236.
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  8. Kung JH, Chen GT, Kuchnir FK. A monitor unit verification calculation in intensity modulated radiotherapy as a dosimetry quality assurance. Med Phys. 2000; 27(10): 2226–2230.
  9. Klimas A, Grządziel A, Plaza D, et al. EPID – a useful interfraction QC tool. Polish Journal of Medical Physics and Engineering. 2019; 25(4): 221–228.
  10. Ślosarek K. Weryfikacja realizacji technik dynamicznych w radioterapii. Inżynier i Fizyk Medyczny. 2013; 2(5).
  11. Malicki J, Ślosarek K. Planowanie leczenia i dozymetria w radioterapii. Via Medica, Gdańsk 2016.
  12. Manual, “RadCalc User Manual Version 7.1 Rev. D”, LifeLine Software Inc.
  13. Manual, “Eclipse Photon and Electron Algorithms Reference Guide”, Varian Medical Systems.

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