An alternative option to reduce lung dose for electron scar boost irradiation in post-mastectomy breast cancer patients with a thin chest wall

Document Type

Article

Publication Date

1-1-2017

Publication Title

Journal of Radiotherapy in Practice

Volume

16

Issue

1

First page number:

20

Last page number:

28

Abstract

Aim: We evaluated water-equivalent slabs as an alternative to a bolus to reduce radiation dose to the underlying lungs during electron scar boost irradiation in breast cancer patients with a thin chest wall undergoing post-mastectomy radiation therapy. Materials and methods: Percent depth doses (PDDs) and attenuation factors were obtained for 6 MeV (the lowest electron energy in most clinics) with solid water slabs (1-10mm by 1mm increments) placed on top of electron cones. Scatter dose to contralateral breast caused by the solid water slabs was measured on a human-like phantom using two selective scar boost patient setups. Results: The PDD plots showed that the solid water slabs had similar dosimetric effects to the bolus with lower skin dose to ipsilateral breast for the same thickness. Slab attenuation and scatter dose to the contralateral breast were increased by ∼220% and by a factor of 3 with a 5mm slab, respectively. Findings: Our results demonstrate the feasibility of using water-equivalent slabs to reduce lung dose for electron scar boost treatment in mastectomy patients with a thin chest wall. However, the increases in treatment time and scatter dose to the contralateral breast are the disadvantages of this approach. © 2016 Cambridge University Press.

Language

english

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