Characterization of a lead breast shielding for dose reduction in computed tomography.
OBJECTIVE
Several studies have been published regarding the use of bismuth shielding to protect the breast in computed tomography (CT) scans and, up to the writing of this article, only one publication about barium shielding was found. The present study was aimed at characterizing, for the first time, a lead breast shielding.


METHODS
The percentage dose reduction and the influence of the shielding on quantitative imaging parameters were evaluated. Dose measurements were made on a CT equipment with the aid of specific phantoms and radiation detectors. A processing software assisted in the qualitative analysis evaluating variations in average CT number and noise on images.


RESULTS
The authors observed a reduction in entrance dose by 30% and in CTDIvol by 17%. In all measurements, in agreement with studies in the literature, the utilization of cotton fiber as spacer object reduced significantly the presence of artifacts on the images. All the measurements demonstrated increase in the average CT number and noise on the images with the presence of the shielding.


CONCLUSIONS
As expected, the data observed with the use of lead shielding were of the same order as those found in the literature about bismuth shielding.
Bachelor degree, Fellow Master degree in Medicine - Area of Investigation in Medical Practice - Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Ribeirão Preto, SP, Brazil.
Paula Duarte
PD
Correia
Bachelor degree, Student of the Program for Mastership and Doctorate in Physics Applied to Medicine and Biology (FAMB), Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto da Universidade de São Paulo (FFCLRP-USP), Ribeirão Preto, SP, Brazil.
Cristiano Roberto Fabri
CR
Granzotti
Undergraduate student of Medical Physics, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto da Universidade de São Paulo (FFCLRP-USP), Ribeirão Preto, SP, Brazil.
Yago da Silva
Yda S
Santos
Master, Medical Physicist Responsible for Radiodiagnosis Quality Control, Unit of Medical Physics and Radioprotection, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brazil.
Marco Aurelio Corte
MA
Brochi
Private Docent, Associate Professor III at Centro de Ciências da Imagem e Física Médica (CCIFM), Coordinator and Supervisor of the Service of Medical Physics and Radioprotection, Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (HCFMRP-USP), Ribeirão Preto, SP, Brazil.
Paulo Mazzoncini
PM
de Azevedo-Marques
Bismuth; Computed tomography; Dose reduction; Lead; Shielding