Experimental photon energy response of different dosimetric materials for a dual detector system combining thermoluminescence and optically stimulated luminescence

Malthez, Anna Luiza Metidieri Cruz; Freitas, Marcos Rabelo de; Yoshimura, Elisabeth Mateus; Button, Vera L. S. N.

doi:10.1016/j.radmeas.2014.07.018

Cited by 13 publications

(5 citation statements)

References 18 publications

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“…To compare the results of this study with those obtained by the aforementioned authors, data of their work, provided by them, were normalized to the results of this study for a common energy, so that results could be comparable in the same graphic (Figure 4.2). The energy-dependent response observed in the results is consistent with the expected, based on the Al2O3:C mass energy absorption coefficient and effective number (Gasparian et al, 2012;Malthez et al, 2014) as it was previously explained (Section 2.7). This energy dependence in diagnostic energy range can be corrected with proper calibration (Gasparian, 2009).…”

Section: Energy Responsesupporting

confidence: 91%

“…The OSL signal for each quality was evaluated by calculating the average of the three responses, and the uncertainties were obtained as the standard deviation of the mean response (k = 1). Responses of the dosimeters for the RQT 8, 9, and 10 beam qualities showed an approximately linear behavior, whereas those for the RQR 2, 4, 5, 6, and 8 followed a non-uniform energy dependence, similar to those found in the literature (Al-Senan & Hatab, 2011;Gasparian et al, 2012;Malthez et al, 2014).…”

Section: Energy Responsesupporting

confidence: 80%

“…Dosimeters presented an energy-dependent response (Figure 4.2). Results obtained in this study were compared to the ones obtained by Gasparian et al (2012) and by Malthez et al (2014). These authors performed a similar analysis with the same kind of OSLD.…”

Section: Energy Responsementioning

confidence: 71%

“…Data from the present study were compared with data obtained by Gasparian et al (2012) and by Malthez et al (2014). Gasparian et al investigated the responses of two types of OSLDs: Al2O3:C single crystals of 5 mm in diameter and 0.9 mm in thickness and Al2O3:C…”

Section: Energy Responsementioning

confidence: 96%

“…Similarly, effective energy was determined for all the x-ray beam qualities. Results were normalized to the RQT 9 x-ray beam quality and then compared to the results provided by other authors (Gasparian, Vanhavere, & Yukihara, 2012;Malthez, Freitas, Yoshimura, & Button, 2014). Table 3.1 summarizes tube voltage (kV), external filtering, HVL and Eeff for each x-ray beam quality.…”

Section: Batch Homogeneitymentioning

confidence: 99%

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Avaliação de doses em órgãos em procedimentos de tomografia computadorizada utilizando dosímetros TL e OSL

Martins¹

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Since the development of the first Computed Tomography (CT) equipment in the early 1970s, this diagnostic imaging modality has gone through several improvements. Exclusively digital and high quality images production without superposition of anatomical structures, examinations as fast as five seconds, and the capability of diagnosing important pathologies with no need of exploratory surgeries are some of the great advantages when using this technique. As a consequence, the role of this diagnostic procedure has been widely increasing worldwide. In the US, for instance, 2.2 million CT exams were performed in 1980, only 10 years after its implementation. This number increased to 78.7 million in 2015. As a result, absorbed dose by patients due to this technique has become a concern among radiologists, researchers and manufacturers, leading to the development of different methodologies to evaluate it. Ionization chambers, thermoluminescence (TL) and, more recently, optically stimulated luminescence (OSL) dosimetry, for instance, have been widely applied in order to estimate in vivo organ doses, in post-mortem subjects and in phantoms. Another approach that has been extensively used are the Monte Carlo simulations, which can be applied in comparison with experimental results. An experimental approach to evaluate organ doses in pediatric and adult anthropomorphic phantoms by using TLDs and OSLDs was employed in the present study. Several analyses were performed in order to stablish the best way to achieve the main results in this investigation and the methodology proved to be efficient. The characteristics of the OSLDs were analyzed to verify their applicability for evaluating doses from CT procedures. The characterization included homogeneity, linearity with the incident air kerma, reproducibility, reusability and an energy-dependent response to distinct effective energies evaluation. These dosimeters were applied along with TLDs in an adult and a pediatric anthropomorphic phantoms to evaluate organ doses due to clinical CT protocols. These protocols were selected after an analysis of patient data collected from the

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Section: Energy Responsesupporting

confidence: 91%

Section: Energy Responsesupporting

confidence: 80%