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Barbosa da Silveira Gatto L, Braz D, Pacifico L, Travassos PC, Goncalves Magalhaes LA. Comparison of spectra and mean glandular dose (MGD) with tube voltage used in digital mammography for simulated, metrological and clinical cases. Appl Radiat Isot 2021; 176:109862. [PMID: 34385091 DOI: 10.1016/j.apradiso.2021.109862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/02/2021] [Accepted: 07/09/2021] [Indexed: 11/16/2022]
Abstract
Mammography has a crucial role in breast cancer detection. The National Cancer Institute (INCA) estimates that 29.7% of the cancer cases in Brazil are related specifically to the breast. It is necessary to evaluate the mean glandular dose with a new solid-state detector in a digital radiography system, utilizing PMMA phantoms and spacers for different thicknesses. The Selenia Dimensions (Hologic, Bedford) direct radiography (DR) system can perform full-field digital mammographies through digital detectors. This system uses new technologies, such as the digital breast tomosynthesis system (DBT), and employs a sequence of projections acquired over the breast, resulting in images with low contrast. The estimation of breast dose is an important part of mammographic quality control for x-ray mammography. Nevertheless, there are currently no standard protocols for the dosimetry of breast imaging in 3D. Additionally, a x-ray spectra function is crucial to measure a considerable output in x-ray spectrometry. The purpose of this work was to assess the mean glandular dose (MGD) and the spectra in slabs of polymethyl methacrylate (PMMA) and breast equivalent thickness through digital mammography using four experiments: a Hologic Selenia Dimensions mammograph with a solid-state detector; a spectrometer (only for the spectra, in this case); a clinical COMET x-ray tube with a solid-state detector; and the MCNPX code. References recommend that the real environments that work well with digital mammography are in the following tube voltages: 25 kVp; 26 kVp; 28 kVp; 31 kVp and 33 kVp. Taking into account several thicknesses of PMMA, the results of both the MGD in metrological, clinical and simulated cases were in accordance with the references, from 30 mm of PMMA. All the spectra for all cases have indicated good agreement with the references.
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Affiliation(s)
- Leandro Barbosa da Silveira Gatto
- COPPE - Rio de Janeiro Federal University (UFRJ), Av. Horácio Macedo, 2030, Bloco G, Cidade Universitária, Ilha do Fundão, CEP 221941-914, Rio de Janeiro, Brazil
| | - Delson Braz
- COPPE - Rio de Janeiro Federal University (UFRJ), Av. Horácio Macedo, 2030, Bloco G, Cidade Universitária, Ilha do Fundão, CEP 221941-914, Rio de Janeiro, Brazil
| | - Leonardo Pacifico
- Radiological Sciences Laboratory (LCR) - Rio de Janeiro State University (UERJ), Rua São Francisco Xavier, PHLC, 524, s136, CEP 20550-900, Rio de Janeiro, Brazil
| | - Paulo Cesar Travassos
- Radiological Sciences Laboratory (LCR) - Rio de Janeiro State University (UERJ), Rua São Francisco Xavier, PHLC, 524, s136, CEP 20550-900, Rio de Janeiro, Brazil
| | - Luis Alexandre Goncalves Magalhaes
- Radiological Sciences Laboratory (LCR) - Rio de Janeiro State University (UERJ), Rua São Francisco Xavier, PHLC, 524, s136, CEP 20550-900, Rio de Janeiro, Brazil.
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Oliveira BB, de Oliveira MA, Paixão L, Teixeira MHA, Nogueira MDS. Dosimetry and image quality assessment in a direct radiography system. Radiol Bras 2015; 47:361-7. [PMID: 25741119 PMCID: PMC4341379 DOI: 10.1590/0100-3984.2013.1876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 04/10/2014] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE To evaluate the mean glandular dose with a solid state detector and the image quality in a direct radiography system, utilizing phantoms. MATERIALS AND METHODS Irradiations were performed with automatic exposure control and polymethyl methacrylate slabs with different thicknesses to calculate glandular dose values. The image quality was evaluated by means of the structures visualized on the images of the phantoms. RESULTS Considering the uncertainty of the measurements, the mean glandular dose results are in agreement with the values provided by the equipment and with internationally adopted reference levels. Results obtained from images of the phantoms were in agreement with the reference values. CONCLUSION The present study contributes to verify the equipment conformity as regards dose values and image quality.
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Affiliation(s)
- Bruno Beraldo Oliveira
- Masters, Fellow PhD degree, Course of Science and Technology of Radiations, Minerals and Materials - Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/ CNEN), Belo Horizonte, MG, Brazil
| | - Marcio Alves de Oliveira
- Master, Teacher, Department of Anatomy and Imaging, School of Medicine - Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Lucas Paixão
- Masters, Fellow PhD degree, Course of Science and Technology of Radiations, Minerals and Materials - Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/ CNEN), Belo Horizonte, MG, Brazil
| | | | - Maria do Socorro Nogueira
- PhD, Titular Researcher-Professor, Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG, Brazil
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Metzger PB, Novero ER, Rossi FH, Moreira SM, Linhares FA, Almeida BLD, Barbato HA, Izukawa NM, Kambara AM. Evaluation of preoperative computed tomography angiography in association with conventional angiography versus computed tomography angiography only, in the endovascular treatment of aortic diseases. Radiol Bras 2013. [DOI: 10.1590/s0100-39842013000500001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective To evaluate the association of conventional angiography (AG) with computed tomography angiography (CTA) as compared with CTA only, preoperatively, in the treatment of aortic diseases. Materials and Methods Retrospective study involving patients submitted to endovascular treatment of aortic diseases, in the period from January 2009 to July 2010, with use of preoperative CTA + conventional AG or CTA only. The patients were divided into two groups, namely: G1 – thoracic aortic diseases; and G2 – abdominal aortic diseases. G1 was subdivided into 1A (preoperative AG + CTA) and 1B (preoperative CTA). G2 was subdivided into 2C (CTA + AG) and 2D (CTA only). Results The authors evaluated 156 patients. In subgroups 1A and 1B, the rate of technical success was, respectively, 100% and 94.7% (p = 1.0); and the rate of therapeutic success was, respectively, 81% and 58% (p = 0.13). A higher number of complications were observed in subgroup 1B (p = 0.057). The accuracy in the calculation of the prosthesis was higher in subgroup 1A (p = 0.065). In their turn, the rate of technical success in subgroups 2C and 2D was, respectively, 92.3% and 98.6% (p = 0.17). The rate of therapeutic success was 73% and 98.6% (p = 0.79). Conclusion Preoperative conventional AG should be reserved for cases where CTA cannot provide all the information in the planning of a therapeutic intervention.
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Oliveira BB, Mourão AP, Silva TAD. Estimativa dos valores de MSAD em procedimentos de tomografia computadorizada utilizando filmes radiocrômicos. Radiol Bras 2013. [DOI: 10.1590/s0100-39842013000200013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
OBJETIVO: Verificar a viabilidade de filmes radiocrômicos como um dosímetro alternativo para estimativa da dose média em cortes múltiplos a partir dos perfis de kerma. MATERIAIS E MÉTODOS: Os filmes foram distribuídos em cilindros posicionados no centro e nas regiões periféricas de um objeto simulador padrão de abdome utilizado para dosimetria em tomografia computadorizada. RESULTADOS: Os valores de dose média em cortes múltiplos calculados foram 13,6 ± 0,7, 13,5 ± 0,7 e 18,7 ± 1,0 mGy para os valores de passo (pitch) de 0,75, 1,00 e 1,50, respectivamente. CONCLUSÃO: Apesar de os resultados mostrarem valores menores que o nível de referência de radiodiagnóstico de 25 mGy estabelecido pela legislação brasileira para exames de abdome, eles sugerem que há espaço para otimização dos procedimentos e uma revisão do valor para o nível de referência de radiodiagnóstico brasileiro.
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