title: Assessment of breast absorbed doses during thoracic computed tomography scan to evaluate the effectiveness of bismuth shielding.
abstract: During a lung computed tomography (CT) examination, breast and nearby radiosensitive organs are unnecessarily irradiated because they are in the path of the primary beam. The purpose of this paper is to determine the absorbed dose in breast and nearby organs for unshielded and shielded exposures with bismuth. The experiment was done with a female anthropomorphic phantom undergoing a typical thoracic CT scan, with TLD-100 thermoluminescent detectors insert at breast, lung and thyroid positions. Results showed that dose reduction due to bismuth shielding was approximately 30% and 50% for breast and thyroid, respectively; however, the influence of the bismuth on the image quality needs to be considered.
authors.affiliation: Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, Belo Horizonte, Brazil; Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Brazil. Electronic address: alonso@cdtn.br.
authors.forename: Thessa C
authors.initials: TC
authors.lastname: Alonso
authors.affiliation: Centro Federal de Educação Tecnológica de Minas Gerais, CEFET, Belo Horizonte, Brazil.
authors.forename: Arnaldo P
authors.initials: AP
authors.lastname: Mourão
authors.affiliation: Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Brazil.
authors.forename: Priscila C
authors.initials: PC
authors.lastname: Santana
authors.affiliation: Centro de Desenvolvimento da Tecnologia Nuclear, CDTN, Belo Horizonte, Brazil; Universidade Federal de Minas Gerais, UFMG, Belo Horizonte, Brazil.
authors.forename: Teógenes A
authors.initials: TA
authors.lastname: da Silva
mesh_terms: D065638:Absorption, Radiation / Q000502:physiology*; D001729:Bismuth / Q000737:chemistry*; D001940:Breast / Q000502:physiology* / Q000528:radiation effects; D004867:Equipment Design; D005260:Female; D006801:Humans; D058958:Organs at Risk / Q000528:radiation effects; D019047:Phantoms, Imaging; D011829:Radiation Dosage; D000069079:Radiation Exposure / Q000032:analysis*; D011835:Radiation Protection / Q000295:instrumentation* / Q000379:methods; D013902:Radiography, Thoracic / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D001729:Bismuth
keywords: Bismuth shielding; Breast and nearby organ absorbed dose in CT; Thoracic CT scan