Energy dependence of TLD 100 and MCP-N detectors

Carinou, E.; Boziari, A.; Askounis, Panagiotis; Mikulis, A.; Kamenopoulou, V.

doi:10.1016/j.radmeas.2007.12.042

Cited by 18 publications

(10 citation statements)

References 5 publications

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“…The annealing procedure applied to the TL dosimeters was the very well-established procedure consisting of a pre-irradiation annealing of 400°C for 1 hour, followed by a heating procedure of 100°C for 2 hours, and a post-irradiation annealing of 100°C for 15 minutes. (21)(22)(23)(24) These procedures was carried out in the automatic oven PTW TLDO. Sixty TL dosimeters were used in this work, of which 52 samples were applied in measurements, while the eight remaining dosimeters were used in the stability control of the TL system.…”

Section: Methodsmentioning

confidence: 99%

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

Rosa

Cardoso

Campos

et al. 2010

J Applied Clin Med Phys

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The purpose of this study is to investigate the influence of lung heterogeneity inside a soft tissue phantom on percentage depth dose (PDD). PDD curves were obtained experimentally using LiF:Mg,Ti (TLD‐100) thermoluminescent detectors and applying Eclipse treatment planning system algorithms Batho, modified Batho (M‐Batho or BMod), equivalent TAR (E‐TAR or EQTAR), and anisotropic analytical algorithm (AAA) for a 15 MV photon beam and field sizes of 1×1,.2em2×2,.2em5×5, and 10×10.2emcm2. Monte Carlo simulations were performed using the DOSRZnrc user code of EGSnrc. The experimental results agree with Monte Carlo simulations for all irradiation field sizes. Comparisons with Monte Carlo calculations show that the AAA algorithm provides the best simulations of PDD curves for all field sizes investigated. However, even this algorithm cannot accurately predict PDD values in the lung for field sizes of 1×1 and 2×2.2emcm2. An overdosage in the lung of about 40% and 20% is calculated by the AAA algorithm close to the interface soft tissue/lung for 1×1 and 2×2.2emcm2 field sizes, respectively. It was demonstrated that differences of 100% between Monte Carlo results and the algorithms Batho, modified Batho, and equivalent TAR responses may exist inside the lung region for the 1×1.2emcm2 field.PACS number: 87.55.kd

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Section: Methodsmentioning

confidence: 99%

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

Rosa

Cardoso

Campos

et al. 2010

J Applied Clin Med Phys

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“…It is noted that the difference in calibration factors obtained for the 80 and 120 kVp beams were less than 4%, while the differences in calibration factors obtained for the 120 and the 140 kVp beams is expected to be lower. 14,15 Apart from the overbeaming effect, which is quantified by the x-ray beam geometric efficiency ͑GE b ͒, there are other features in modern MD CT systems that deteriorate radiation dose utilization efficiency. In MDCT systems the detector array is made by a large number of detector elements separated with septa that absorb radiation without producing signal.…”

Section: Beam Collimation ͑Mm͒mentioning

confidence: 99%

The effect of x‐ray beam quality and geometry on radiation utilization efficiency in multidetector CT imaging

2009

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This study has the following objectives: To measure the geometric efficiency (GE) of a multidetector CT (MDCT) system and investigate its dependence on several exposure parameters and to correlate GE with radiation dose burden of patients undergoing MDCT imaging. Dose profiles for all available beam collimations, tube voltage values, focal spot sizes, and modes of operation were determined for a modern MDCT scanner using an array of thermoluminescent chip dosimeters positioned side by side. Dose profiles measured free-in-air and at the center and periphery of the standard polymethyl methacrylate (PMMA) phantoms were used to estimate GE. The standard free-in-air and a new measure of GE determined using the standard PMMA phantoms were correlated with volume computed tomography dose index normalized to the z-axis coverage per rotation which is directly related to patient radiation dose burden. GE was found to be from 30% to 88% as beam collimation was changed from 1.2 to 24 mm, with thin beam collimations corresponding to higher "wasted" dose. For the same tube voltage and beam collimation, the use of small focal spot was associated with higher GE compared to the large focal spot. Besides, beam quality was found to have a much weaker effect on the GE value. In comparison to free-in-air, a weighted GE determined using the standard PMMA phantoms was found to have significantly better correlation with patient radiation burden (p < 0.05). Overbeaming strongly depends on the beam collimation and focal spot size, while the impact of beam quality on GE is less pronounced. Thin beam collimations are associated with a GE of as low as 30%.

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“…However, all the performed studies agreed that TL dosimeters have noticeable photon energy dependence at energies below a few hundred keV [21][22][23].…”

Section: Introductionmentioning

confidence: 90%

Investigation of TLD-700 energy response to low energy x-ray encountered in diagnostic radiology

2016

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Abstract:The aim of this work is to study the energy dependence of thermoluminescent dosimeter (TLD-700) for low energy X-ray beams encountered in conventional diagnostic radiology. In the rst step, we studied some characteristics (reproducibility and linearity) of TLD-700 chips using a Cs source, and selected TLD chips with reproducibility better than 2.5%. Then we determined TLD-700 energy response for diagnostic radiology X-ray qualities, and investigated its in uence on air kerma estimate. A maximum deviation of 60% can be obtained if TLDs are calibrated for Cs radiation source and used in diagnostic radiology elds. However, this deviation became less than 20% if TLDs chips are calibrated for the reference x-ray radiation quality RQR5 (recommended by the IEC 61267 standard). Consequently, we recommend calibrating this kind of TLD detector with RQR5 diagnostic radiology X-ray quality. This method permits to obtain a good accuracy when assessing the entrance dose in diagnostic radiology procedures.

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Energy dependence of TLD 100 and MCP-N detectors

Cited by 18 publications

References 5 publications

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

Percentage depth dose evaluation in heterogeneous media using thermoluminescent dosimetry

The effect of x‐ray beam quality and geometry on radiation utilization efficiency in multidetector CT imaging

Investigation of TLD-700 energy response to low energy x-ray encountered in diagnostic radiology

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