Establishing the impact of temporary tissue expanders on electron and photon beam dose distributions

• Published in: Physica medica 2015-05, Vol.31 (3), p.281-285
• Main Authors: Asena, A, Kairn, T, Crowe, S.B, Trapp, J.V
• Format: Article
• Language: English
• Subjects: Breast Neoplasms - radiotherapy; Breast Neoplasms - surgery; Dose distribution; Electrons - therapeutic use; High-density; Humans; Magnet; Mastectomy; Photons - therapeutic use; Radiation Dosage; Radiology; Radiotherapy Dosage; Tissue expander; Tissue Expansion Devices
• ISSN: 1120-1797; 1724-191X
• DOI: 10.1016/j.ejmp.2015.01.015

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.