| Texto completo | |
| Autor(es): |
Santos, Josilene C.
;
Tomal, Alessandra
;
Furquim, Tania A.
;
Fausto, Agnes M. F.
;
Nogueira, Maria S.
;
Costa, Paulo R.
Número total de Autores: 6
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Medical Physics; v. 44, n. 7, p. 3504-3511, JUL 2017. |
| Citações Web of Science: | 5 |
| Resumo | |
Purpose: To introduce and evaluate a method developed for the direct measurement of mammographic x-ray spectra using a CdTe spectrometer. The assembly of a positioning system and the design of a simple and customized alignment device for this application is described. Methods: A positioning system was developed to easily and accurately locate the CdTe detector in the x-ray beam. Additionally, an alignment device to line up the detector with the central axis of the radiation beam was designed. Direct x-ray spectra measurements were performed in two different clinical mammography units and the measured x-ray spectra were compared with computer-generated spectra. In addition, the spectrometer misalignment effect was evaluated by comparing the measured spectra when this device is aligned relatively to when it is misaligned. Results: The positioning and alignment of the spectrometer have allowed the measurements of direct mammographic x-ray spectra in agreement with computer-generated spectra. The most accurate x-ray spectral shape, related with the minimal HVL value, and high photon fluence for measured spectra was found with the spectrometer aligned according to the proposed method. The HVL values derived from both simulated and measured x-ray spectra differ at most 1.3 and 4.5% for two mammography devices evaluated in this study. Conclusion: The experimental method developed in this work allows simple positioning and alignment of a spectrometer for x-ray spectra measurements given the geometrical constraints and maintenance of the original configurations of mammography machines. (C) 2017 American Association of Physicists in Medicine (AU) | |
| Processo FAPESP: | 10/12237-7 - Estudo experimental das relações entre Kerma no ar e equivalente de dose ambiente para o cálculo de barreiras primárias em salas radiológicas |
| Beneficiário: | Paulo Roberto Costa |
| Linha de fomento: | Auxílio à Pesquisa - Regular |
| Processo FAPESP: | 13/07117-0 - Determinação experimental da distribuição da dose glandular média em diferentes qualidades de feixes mamográficos |
| Beneficiário: | Josilene Cerqueira Santos |
| Linha de fomento: | Bolsas no Brasil - Doutorado |
| Processo FAPESP: | 15/21873-8 - Desenvolvimento e implementação de metodologias para otimização de técnicas de imagens em radiologia digital |
| Beneficiário: | Alessandra Tomal |
| Linha de fomento: | Auxílio à Pesquisa - Regular |