Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm Journal Article


Authors: Hong, L.; Ballangrud, A.; McCormick, B.; Mechalakos, J.
Article Title: Electron postmastectomy chest wall plus comprehensive nodal irradiation technique using Electron Monte Carlo dose algorithm
Abstract: For left-sided postmastectomy patients requiring chest wall plus comprehensive nodal irradiation, sometimes traditional techniques such as partial wide tangents or electron/tangents combination are not feasible due to abnormal chest wall contour or heart position or unusually wide excision scar. We developed electron chest wall irradiation technique using Electron Monte Carlo (EMC) dose algorithm that will achieve heart sparing with acceptable ipsilateral lung dose, minimal contralateral lung, and breast dose. Ten left-sided postmastectomy patients with very challenging anatomy were selected for this dosimetry study. The en face electron fields were designed from a single isocenter and gantry angle with different energy beams using different cutouts that matched on the skin. Smaller energy was used in the central thin chest wall part and higher energy in the medial internal mammary nodes (IMN) area, superior part of the thick chest wall, and/or axillary nodal area. The electron fields were matched to the photon supraclavicular field in the superior region. Daily field junctions were used to feather the match lines between all the fields. Electron field dose calculations were done with Monte Carlo. Five patients’ chest wall fields were planned with 6/9MeVcombination, 1 with 6/12 MeV, 2 with 9/12 MeV, 1 with 9/16 MeV, and 1 with 6/9/12 MeV. Institutional criteria of prescription dose of 50 Gy for target volumes and normal tissue dose were met with this technique in spite of the challenging anatomy. Mean heart dose averaged 3.0 Gy ± 0.8 Gy. For ipsilateral lung, V20Gy and V5Gy averaged 33.2% ± 4.5% and 64.6% ± 9.6%, respectively. For contralateral lung, V5Gy averaged 5.1% ± 5.0%. For contralateral breast, V5Gy averaged 3.3% ± 3.1%. The electron chest wall irradiation technique using EMC dose algorithm can provide adequate dose coverage to the chest wall, IMNs, and/or axillary nodes while achieving heart sparing with acceptable ipsilateral lung dose, minimal contralateral lung, and breast dose. © 2017 American Association of Medical Dosimetrists
Keywords: electron monte carlo dose calculations; electron postmastectomy chest wall irradiation; heart sparing
Journal Title: Medical Dosimetry
Volume: 43
Issue: 3
ISSN: 0958-3947
Publisher: Elsevier Science, Inc.  
Date Published: 2018-01-01
Start Page: 230
End Page: 236
Language: English
DOI: 10.1016/j.meddos.2017.08.011
PROVIDER: scopus
PUBMED: 29032865
DOI/URL:
Notes: The publisher's record lists the publication date as Autumn -- Article -- Export Date: 1 August 2018 -- Source: Scopus
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MSK Authors
  1. Linda Xueqi Hong
    47 Hong
  2. Beryl McCormick
    243 McCormick