ABSTRACT
PURPOSE
In this paper we present a phantom designed to provide conditions to generate set
of “true” independent reference data as requested by TG-186, and mitigating the scarcity
of experimental studies on brachytherapy validation. It was used to perform accurate
experimental measurements of dose of 125I brachytherapy seeds using LiF dosimeters, with the objective of experimentally validating
Monte Carlo (MC) calculations with model-based dose calculation algorithm (MBDCA).
In addition, this work intends to evaluate a methodology to convert the experimental
values from LiF into dose in the medium.
METHODS AND MATERIALS
The proposed PMMA physical phantom features cavities to insert a LiF dosimeter and
a 125I seed, adjusted in different configurations with variable thickness. Monte Carlo
calculations performed with MCNP6.2 code were used to score the absorbed dose in the
LiF and the dose conversion parameters. A sensitivity analysis was done to verify
the source of possible uncertainties and quantify their impact on the results.
RESULTS
The proposed phantom and experimental procedure developed in this work provided precise
dose data within 5.68% uncertainty (k = 1). The achieved precision made it possible to convert the LiF responses into absorbed
dose to medium and to validate the dose conversion factor methodology.
CONCLUSIONS
The proposed phantom is simple both in design and as in its composition, thus achieving
the demanded precision in dose evaluations due to its easy reproducibility of experimental
setup. The results derived from the phantom measurements support the dose conversion
methodology. The phantom and the experimental procedure developed here can be applied
for other materials and radiation sources.
Keywords
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Article info
Publication history
Published online: November 14, 2022
Accepted:
October 9,
2022
Received in revised form:
September 15,
2022
Received:
June 29,
2022
Footnotes
Disclosure: The authors report no proprietary or commercial interest in any product mentioned or concept discussed in this article.
Identification
Copyright
© 2022 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.
