A Monte Carlo study of the quality dependence factors of common TLD materials in photon and electron beams

Mobit, Paul N; Nahum, Alan E.; Mayles, Philip

doi:10.1088/0031-9155/43/8/002

Cited by 53 publications

(35 citation statements)

References 28 publications

(47 reference statements)

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“…In dosimetry it is frequently assumed that the quality dependence of thermonuminescence LiF:Mg,Ti detectors such as TLD-100, follows the ratio of the energy absorption coefficient for the LiF and water. It has been shown by Mobit et al (1998), that the quality dependence factor for LiF-TLD in kilovoltage x-rays relative to 60 C 0 gamma-rays ranges from 1.36 for 50 kV x-rays to 1.03 for 300 kV which are comparable with our results [10]. Kearfott et al (1990) observed an quality dependence factor of LiF TL ribbon from 1.045 (50 keV) to 1.353 (100 keV) [12].…”

Section: Discussionsupporting

confidence: 91%

See 1 more Smart Citation

Monte Carlo Simulation of TLD Response Function: Scatterd Radiation Application

Mahdavi¹,

Shirazi²,

Khodadadee³

et al. 2011

Applications of Monte Carlo Methods in Biology, Medicine and Other Fields of Science

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Section: Discussionsupporting

confidence: 91%

“…Monte Carlo calculation did not show any difference in behaviour of pure LiF and TLD-100 in kilovoltage or megavoltage x-ray ranges. This is expected since the concentration of Ti and Mg by weight is negligible in TLD-100 [10]. The TLD chips were represented by 3.1 mm ×3.1 mm×1 mm.…”

Section: Monte Carlo Simulationmentioning

confidence: 96%

Monte Carlo Simulation of TLD Response Function: Scatterd Radiation Application

Mahdavi¹,

Shirazi²,

Khodadadee³

et al. 2011

Applications of Monte Carlo Methods in Biology, Medicine and Other Fields of Science

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“…The generation of a separate calibration factor (RCF) for each beam quality improved the overall result compared to a single calibration factor. No correction factors derived from published models 26 were applied in this work. The TLDs were also given a known absorbed dose in the 300 kV p therapy beam and then read using the RCF of the 180 kV p therapy beam.…”

Section: Tld Calibration Results At the Simulatormentioning

confidence: 99%

“…In some cases, the use of monoenergetic photon beams along with mathematical models have been employed to predict the energy dependence of TLD response 23,24 . Correction factors for different beam qualities have also been generated to compensate for this effect 26 . According to Kron et al 23 , variation in TLD response could be due to the assumption that the response at low energies reduces exponentially whereas at medium energies, it varies according to the energy dependence from the photoelectric effect.…”

Section: Tld Calibration Results At the Simulatormentioning

confidence: 99%

Thermoluminescent dosimetry in clinical kilovoltage beams

et al. 2013

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Aim: This study aimed at calibrating a new set of GR-200A thermoluminescent dosimeters (TLDs) in low and medium kilovoltage energy photon therapy beams and in a diagnostic beam of known beam quality, in order to determine their response and to establish if the same set of TLDs could be used across both environments for in-vivo dosimetry purposes. Methods and Materials:A set of 20 TLDs was used for this study. An Oven type PCL 3 was used to anneal the TLDs. The response of the TLDs was read using the Reader type LTM manufactured by Harshaw Bicron, United State of America. Vacuum tweezers were used to transfer the TLDs at the time of measurements and calibration. TLDs were kept in a subdued ultra-violet environment between the annealing and irradiation process.TLDs were placed on a 30 x 30 x 17.6 cm³ Polymethylmethacrylate (PMMA) phantom during irradiation. A calibrated Orthovoltage machine was used to deliver a known absorbed dose to the TLDs. A cylindrical ionization chamber (PTW 30001) and an electrometer (PTW 10008) were used to confirm the absorbed dose delivery of the orthovoltage machine at the time of measurement. Likewise, a calibrated LX40 radiotherapy Simulator was used to deliver a known diagnostic absorbed dose to the TLDs. A TM77334 ionization chamber was used similarly to confirm the absorbed dose.The TLDs were also irradiated on the PMMA phantom. The accepted variation in raw response of the individual TLDs from the average of the batch was compared and a deviation of less than ± 20 % was considered within tolerance. A 10 % tolerance was subsequently considered suitable for the measurement of absorbed dose. 16 of the 17 TLDs were within ± 10 % dose tolerance at 95 kV p whereas all the TLDs that were within the accepted response level at the 180 kV p and 300 kV p , were within the iii ± 10 % dose tolerance. 12 of the 15 TLDs at the diagnostic beam energy were within the ± 10 % dose tolerance. Three of the TLDs were therefore rejected at all energies. Conclusion

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“…Mobit et al [11] performed Monte Carlo study of the quality dependence of LiF TLD in kilovoltage photon beams for radiotherapy dosimetry studies. Kearfott et al [12] observed an energy response of LiF TL ribbon for low energy x-rays.…”

Section: Introductionmentioning

confidence: 99%

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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A Monte Carlo study of the quality dependence factors of common TLD materials in photon and electron beams

Cited by 53 publications

References 28 publications

Monte Carlo Simulation of TLD Response Function: Scatterd Radiation Application

Monte Carlo Simulation of TLD Response Function: Scatterd Radiation Application

Thermoluminescent dosimetry in clinical kilovoltage beams

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

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