| Full text | |
| Author(s): |
Santoro-Fernandes, V
[1]
;
Santos, J. C.
[1, 2]
;
Mariano, L.
[1]
;
Vanin, V. R.
[1]
;
Costa, P. R.
[1]
Total Authors: 5
|
| Affiliation: | [1] Univ Sao Paulo, Inst Phys, Sao Paulo - Brazil
[2] Univ Fed Rio de Janeiro, Inst Phys, Rio De Janeiro - Brazil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | BIOMEDICAL PHYSICS & ENGINEERING EXPRESS; v. 6, n. 3 APR 2020. |
| Web of Science Citations: | 0 |
| Abstract | |
Numerical models are an alternative to measurements of x-ray energy spectra when validated by comparative methods that assess the similarity of experimental and calculated spectra. In this work, we compared x-ray energy spectra using several methodologies and determined the methodology with highest statistical power among them. Experiments and Monte Carlo (MC) simulations were used to generate a set of 65 experimental and simulated x-ray mammography spectra pairs typically used in mammography applications. They were generated using Tungsten and Molybdenum targets and Molybdenum and Rhodium filters. The x-ray beams were transmitted through breast tissue equivalent material (bTEM) plates with different glandularities and thicknesses, and the transmitted beam was detected using solid-state x-ray spectrometry with a Cadmium Telluride (CdTe) diode. The MC simulations used the PENELOPE code. Additional uncertainties, beyond that from counting, were propagated using the MC method. Quantitative comparative methods based on the chi(2) statistics, the first and second half-value layers, the mean energy, the effective energy, and the non-parametric u-test were applied and their specificity (true negative rate) was assessed. The polyenergetic normalized glandular dose (DgNp) to a 6 cm breast of 50/50 glandularity was derived from the spectra. In this work, the chi(2) statistics attained the highest score; therefore, it is the most indicated metric for the x-ray energy spectra comparative evaluations. The contribution of the additional uncertainties was important, being responsible for up to 98% of the spectra total uncertainty and shifting the mean of the evaluated chi(2) to 1.2(1), compatible with its expected value. The use of non-parametric test is discouraged by our results, since it failed to distinguish spectra pairs that resulted in up to 72% discrepant DgNp. (AU) | |
| 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: | 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 |