title: Determination of backscatter factors in breast tomosynthesis using MCNPX simulations and measurements.
abstract: The perspective of adding digital breast tomosynthesis (DBT) to standard mammography in screening raises concerns regarding the dose absorbed by the fibroglandular breast tissue. Thus, it is important to estimate accurately the mean glandular dose (MGD), although there are no standard protocols for dosimetry, concerning DBT. This study aims at introducing backscatter factors (BSF) to calculate the entrance surface air kerma (ESAK), directly on patients or phantoms, in order to be introduced in the formalism proposed by Dance et al. MCNPX simulations were performed, to mimic a DBT acquisition, for a wide range of X-ray spectra. A homogeneous breast phantom with 50 % of glandular tissue was considered and several thicknesses were evaluated. Dose measurements were performed, to validate and support the simulation results. The BSF may indicate a real MGD estimation in vivo for DBT examinations and contribute for the improvement of the current guidelines used in these applications.
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066, Portugal marianabaptista@ctn.ist.utl.pt.
authors.forename: M
authors.initials: M
authors.lastname: Baptista
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066, Portugal.
authors.forename: S
authors.initials: S
authors.lastname: Di Maria
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066, Portugal.
authors.forename: C
authors.initials: C
authors.lastname: Figueira
authors.affiliation: Serviço de Imagiologia, Hospital da Luz, Avenida Lusíada, 100, Lisboa 1500-650, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Orvalho
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, km 139,7, Bobadela LRS 2695-066, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Vaz
mesh_terms: D000388:Air; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D003198:Computer Simulation; D004867:Equipment Design; D005260:Female; D006801:Humans; D008327:Mammography / Q000379:methods*; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D011874:Radiometry; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D014965:X-Rays