title: Optimal photon energy comparison between digital breast tomosynthesis and mammography: a case study.
abstract: A comparison, in terms of the optimal energy that maximizes the image quality between digital breast tomosynthesis (DBT) and digital mammography (DM) was performed in a MAMMOMAT Inspiration system (Siemens) based on amorphous selenium flat panel detector. In this paper we measured the image quality by the signal difference-to-noise ratio (SDNR), and the patient risk by the mean glandular dose (MGD). Using these quantities we compared the optimal voltage that maximizes the image quality both in breast tomosynthesis and standard mammography acquisition mode. The comparison for the two acquisition modes was performed for a W/Rh anode filter combinations by using a 4.5 cm tissue equivalent mammography phantom. Moreover, in order to check if the used equipment was quantum noise limited, the relation of the relative noise with respect to the detector dose was evaluated. Results showed that in the tomosynthesis acquisition mode the optimal voltage is 28 kV, whereas in standard mammography the optimal voltage is 30 kV. The automatic exposure control (AEC) of the system selects 28 kV as optimal voltage both for DBT and DM. Monte Carlo simulations showed a qualitative agreement with the AEC selection system, since an optimal monochromatic energy of 20 keV was found both for DBT and DM. Moreover, the check about the noise showed that the system is not completely quantum noise limited, and this issue could explain the experimental slight difference in terms of optimal voltage between DBT and DM. According to these results, the use of higher voltage settings is not justified for the improvement of the image quality during a DBT examination.
authors.affiliation: Centro de Ciência e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, Km 139,7, 2695-066 Bobadela, Portugal. Electronic address: salvatore@ctn.ist.utl.pt.
authors.forename: S
authors.initials: S
authors.lastname: Di Maria
authors.affiliation: Centro de Ciência e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, Km 139,7, 2695-066 Bobadela, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Baptista
authors.affiliation: Centro de Ciência e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, Km 139,7, 2695-066 Bobadela, Portugal.
authors.forename: M
authors.initials: M
authors.lastname: Felix
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Instituto de Biofísica e Engenharia Biomédica, Campo Grande, 1749-016 Lisboa, Portugal.
authors.forename: N
authors.initials: N
authors.lastname: Oliveira
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências, Instituto de Biofísica e Engenharia Biomédica, Campo Grande, 1749-016 Lisboa, Portugal.
authors.forename: N
authors.initials: N
authors.lastname: Matela
authors.affiliation: Escola Superior de Saúde da Cruz Vermelha Portuguesa, Avenida de Ceuta, 1, Edifício Urbiceuta, 1300-125 Lisboa, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Janeiro
authors.affiliation: Centro de Ciência e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, Km 139,7, 2695-066 Bobadela, Portugal.
authors.forename: P
authors.initials: P
authors.lastname: Vaz
authors.affiliation: Serviço de Imagiologia, Hospital da Luz, Avenida Lusíada, 100, 1500-650 Lisboa, Portugal.
authors.forename: L
authors.initials: L
authors.lastname: Orvalho
authors.affiliation: Serviço de Imagiologia, Hospital da Luz, Avenida Lusíada, 100, 1500-650 Lisboa, Portugal.
authors.forename: A
authors.initials: A
authors.lastname: Silva
mesh_terms: D001940:Breast; D004583:Electrons; D007091:Image Processing, Computer-Assisted; D008327:Mammography / Q000295:instrumentation / Q000379:methods*; D009010:Monte Carlo Method; D019047:Phantoms, Imaging; D017785:Photons; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods*; D059629:Signal-To-Noise Ratio
keywords: Digital breast tomosynthesis; Digital mammography; Image quality; Mean glandular dose; Monte Carlo simulations