Highlights
- •Accuracy of treatments can be compromised by temporary tissue expanders.
- •Discrepancies in literature between backscatter and dose reduction measurements.
- •Film measurements taken for different phantoms, and beam setups.
- •An accurately modelled high-density implant in the TPS is required.
Abstract
Purpose
This study investigates the effects of temporary tissue expanders (TTEs) on the dose
distributions in breast cancer radiotherapy treatments under a variety of conditions.
Methods
Using EBT2 radiochromic film, both electron and photon beam dose distribution measurements
were made for different phantoms, and beam geometries. This was done to establish
a more comprehensive understanding of the implant's perturbation effects under a wider
variety of conditions.
Results
The magnetic disk present in a tissue expander causes a dose reduction of approximately
20% in a photon tangent treatment and 56% in electron boost fields immediately downstream
of the implant. The effects of the silicon elastomer are also much more apparent in
an electron beam than a photon beam.
Conclusions
Evidently, each component of the TTE attenuates the radiation beam to different degrees.
This study has demonstrated that the accuracy of photon and electron treatments of
post-mastectomy patients is influenced by the presence of a tissue expander for various
beam orientations. The impact of TTEs on dose distributions establishes the importance
of an accurately modelled high-density implant in the treatment planning system for
post-mastectomy patients.
Keywords
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References
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Article info
Publication history
Published online: February 15, 2015
Accepted:
January 19,
2015
Received in revised form:
January 16,
2015
Received:
June 24,
2014
Identification
Copyright
© 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Inc. All rights reserved.