Advanced search
Start date
Betweenand
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Normalized glandular dose (DgN) coefficients from experimental mammographic x-ray spectra

Full text
Author(s):
Santos, Josilene C. [1] ; Tomal, Alessandra [2] ; de Barros, Nestor [3] ; Costa, Paulo R. [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Fis, BR-05508090 Sao Paulo, SP - Brazil
[2] IFGW UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil
[3] Univ Sao Paulo, Fac Med, BR-05403900 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Physics in Medicine and Biology; v. 64, n. 10 MAY 2019.
Web of Science Citations: 0
Abstract

Mean glandular dose is the quantity used for dosimetry in mammography and depends on breast-related characteristics, such as thickness and density, and on the x-ray spectrum used for breast imaging. This work aims to present an experimentally-based method to derive polyenergetic normalized glandular dose coefficients (DgN(p)) from the spectral difference between x-ray spectra incident and transmitted through breast phantoms with glandular/adipose proportions of 30/70 and 50/50 and thicknesses up to 4.5 cm. The spectra were produced by a Mammomat 3000 Nova system using radiographic techniques commonly applied for imaging compressed breast thickness lower than 6 cm (Mo/Mo, Mo/Rh and W/Rh spectra at 26 and 28 kVp). DgN(p) coefficients were compared with values estimated using Boones' method and data from breast images (DICOM Organ Dose and VolparaDose calculations). The DgN(p) were also evaluated in layers into the phantoms (depth-DgN(p)) using both x-ray spectra and thermoluminescent dosimeters (TLD-100). Maximum differences between DgN(p) from the method presented in this study and results using Boone's method was 11%, with larger differences for Mo/Rh spectra in relation to the Mo/Mo. The DgN(p) maximum differences to the coefficients obtained using patient images were 8.0%, for the DgN calculated using Volpara and 6.4% for the DgN from DICOM Organ Dose, for a 4.5 cm breast phantom with 30% glandularity. The DgN(p) estimated from the depth-DgN(p) distributions differ up to 5.2% to the coefficients obtained using the pair incident-transmitted spectra to calculate the DgN(p) directly in the whole phantom. The depth-DgN(p) distributions estimated with TLDs were consistent with the results observed using the experimental spectra, with maximum difference of 3.9%. In conclusion, polyenergetic x-ray spectrometry proved to be an applicable tool for research in dosimetry in mammography allowing spectral characterization. This approach can also be useful for investigation of the influence of x-ray spectra on glandular dose. (AU)

FAPESP's process: 13/07117-0 - EXPERIMENTAL DETERMINATION OF THE MEAN GLANDULAR DOSE DISTRIBUTION IN DIFFERENT MAMMOGRAPHIC BEAM QUALITIES
Grantee:Josilene Cerqueira Santos
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 10/12237-7 - Experimento evaluation of the relation between air-Kerma and ambient equivalent dose for shielding calculation in adult and pediatric X-ray rooms
Grantee:Paulo Roberto Costa
Support Opportunities: Regular Research Grants
FAPESP's process: 15/21873-8 - Establishment and application of methodologies for optimizing imaging techniques in digital radiology
Grantee:Alessandra Tomal
Support Opportunities: Regular Research Grants