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Title: SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm

Abstract

Purpose: It is essential to assess the lung dose during TBI to reduce toxicity. Here we characterize the accuracy of the AAA and Acuros algorithms when using cerrobend lung shielding blocks at an extended distance for TBI. Methods: We positioned a 30×30×30 cm3 solid water slab phantom at 400 cm SSD and measured PDDs (Exradin A12 and PTW parallel plate ion chambers). A 2 cm thick, 10×10 cm2 cerrobend block was hung 2 cm in front of the phantom. This geometry was reproduced in the planning system for both AAA and Acuros. In AAA, the mass density of the cerrobend block was forced to 9.38 g/cm3 and in Acuros it was forced to 8.0 g/cm3 (limited to selecting stainless steel). Three different relative electron densities (RED) were tested for each algorithm; 4.97, 6.97, and 8.97. Results: PDDs from both Acuros and AAA underestimated the delivered dose. AAA calculated that depth dose was higher for RED of 4.97 as compared to 6.97 and 8.97 but still lower than measured. There was no change in the percent depth dose with changing relative electron densities for Acuros. Conclusion: Care should be taken before using AAA or Acuros with cerrobend blocks as the planningmore » system underestimates dose. Acuros limits the ability to modify RED when compared to AAA.« less

Authors:
;  [1]
  1. University of Miami, Miami, FL (United States)
Publication Date:
OSTI Identifier:
22649007
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 43; Journal Issue: 6; Other Information: (c) 2016 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; ACCURACY; DEPTH DOSE DISTRIBUTIONS; ELECTRON DENSITY; IONIZATION CHAMBERS; STAINLESS STEELS

Citation Formats

Lamichhane, N, and Studenski, M. SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm. United States: N. p., 2016. Web. doi:10.1118/1.4956598.
Lamichhane, N, & Studenski, M. SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm. United States. doi:10.1118/1.4956598.
Lamichhane, N, and Studenski, M. Wed . "SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm". United States. doi:10.1118/1.4956598.
@article{osti_22649007,
title = {SU-F-T-413: Calculation Accuracy of AAA and Acuros Using Cerrobend Blocks for TBI at 400cm},
author = {Lamichhane, N and Studenski, M},
abstractNote = {Purpose: It is essential to assess the lung dose during TBI to reduce toxicity. Here we characterize the accuracy of the AAA and Acuros algorithms when using cerrobend lung shielding blocks at an extended distance for TBI. Methods: We positioned a 30×30×30 cm3 solid water slab phantom at 400 cm SSD and measured PDDs (Exradin A12 and PTW parallel plate ion chambers). A 2 cm thick, 10×10 cm2 cerrobend block was hung 2 cm in front of the phantom. This geometry was reproduced in the planning system for both AAA and Acuros. In AAA, the mass density of the cerrobend block was forced to 9.38 g/cm3 and in Acuros it was forced to 8.0 g/cm3 (limited to selecting stainless steel). Three different relative electron densities (RED) were tested for each algorithm; 4.97, 6.97, and 8.97. Results: PDDs from both Acuros and AAA underestimated the delivered dose. AAA calculated that depth dose was higher for RED of 4.97 as compared to 6.97 and 8.97 but still lower than measured. There was no change in the percent depth dose with changing relative electron densities for Acuros. Conclusion: Care should be taken before using AAA or Acuros with cerrobend blocks as the planning system underestimates dose. Acuros limits the ability to modify RED when compared to AAA.},
doi = {10.1118/1.4956598},
journal = {Medical Physics},
number = 6,
volume = 43,
place = {United States},
year = {Wed Jun 15 00:00:00 EDT 2016},
month = {Wed Jun 15 00:00:00 EDT 2016}
}