<abstract xmlns="http://www.w3.org/1999/xhtml"><sec id="j_raon-2020-0051_s_006_w2aab3b7c21b1b6b1aab1c16b1Aa"><h3>Introduction</h3><p>Advanced, Monte Carlo (MC) based dose calculation algorithms, determine absorbed dose as dose to medium-in-medium (<italic>D</italic><sub>m,m</sub>) or dose to water-in-medium (<italic>D</italic><sub>w,m</sub>). Some earlier studies identified the differences in the absorbed doses related to the calculation mode, especially in the bone density equivalent (BDE) media. Since the calculation algorithms built in the treatment planning systems (TPS) should be dosimetrically verified before their use, we analyzed dose differences between two calculation modes for the Elekta Monaco TPS. We compared them with experimentally determined values, aiming to define a supplement to the existing TPS verification methodology.</p></sec><sec id="j_raon-2020-0051_s_007_w2aab3b7c21b1b6b1aab1c16b2Aa"><h3>Materials and methods</h3><p>In our study, we used a 6 MV photon beam from a linear accelerator. To evaluate the accuracy of the TPS calculation approaches, measurements with a Farmer type chamber in a semi-anthropomorphic phantom were compared to those obtained by two calculation options. The comparison was made for three parts of the phantom having different densities, with a focus on the BDE part.</p></sec><sec id="j_raon-2020-0051_s_008_w2aab3b7c21b1b6b1aab1c16b3Aa"><h3>Results</h3><p>Measured and calculated doses were in agreement for water and lung equivalent density materials, regardless of the calculation mode. However, in the BDE part of the phantom, mean dose differences between the calculation options ranged from 5.7 to 8.3%, depending on the method used. In the BDE part of the phantom, neither of the two calculation options were consistent with experimentally determined absorbed doses.</p></sec><sec id="j_raon-2020-0051_s_009_w2aab3b7c21b1b6b1aab1c16b4Aa"><h3>Conclusions</h3><p>Based on our findings, we proposed a supplement to the current methodology for the verification of commercial MC based TPS by performing additional measurements in BDE material.</p></sec></abstract>

IntroductionAdvanced, Monte Carlo (MC) based dose calculation algorithms, determine absorbed dose as dose to medium-in-medium (Dm,m) or dose to water-in-medium (Dw,m). Some earlier studies identified the differences in the absorbed doses related to the calculation mode, especially in the bone density equivalent (BDE) media. Since the calculation algorithms built in the treatment planning systems (TPS) should be dosimetrically verified before their use, we analyzed dose differences between two calculation modes for the Elekta Monaco TPS. We compared them with experimentally determined values, aiming to define a supplement to the existing TPS verification methodology.Materials and methodsIn our study, we used a 6 MV photon beam from a linear accelerator. To evaluate the accuracy of the TPS calculation approaches, measurements with a Farmer type chamber in a semi-anthropomorphic phantom were compared to those obtained by two calculation options. The comparison was made for three parts of the phantom having different densities, with a focus on the BDE part.ResultsMeasured and calculated doses were in agreement for water and lung equivalent density materials, regardless of the calculation mode. However, in the BDE part of the phantom, mean dose differences between the calculation options ranged from 5.7 to 8.3%, depending on the method used. In the BDE part of the phantom, neither of the two calculation options were consistent with experimentally determined absorbed doses.ConclusionsBased on our findings, we proposed a supplement to the current methodology for the verification of commercial MC based TPS by performing additional measurements in BDE material.

Experimental validation of Monte Carlo based treatment planning system in bone density equivalent media

Radiology and Oncology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

IntroductionAdvanced, Monte Carlo (MC) based dose calculation algorithms, determine absorbed dose as dose to medium-in-medium (Dm,m) or dose to water-in-medium...

Experimental validation of Monte Carlo based treatment planning system in bone density equivalent media

Article Category: Research Article

Published Online: Sep 16, 2020

Page range: 495 - 504

Received: Jun 10, 2020

Accepted: Jul 09, 2020

DOI: https://doi.org/10.2478/raon-2020-0051

© 2020 Djeni Smilovic Radojcic, Bozidar Casar, David Rajlic, Manda Svabic Kolacio, Ignasi Mendez, Nevena Obajdin, Dea Dundara Debeljuh, Slaven Jurkovic, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.