• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.231-236
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• 2005

Dosimeters are manufactured from same process in the manufacturer but the deviation of TL raw counts exists among the dosimeters. TL raw counts are also gradually degrade due to multiple readings and physical abuse. ECF (Element Correction Factor) correct the degradation and deviation of TL raw counts to the average TL raw counts of reference dosimeters. Procedures for producing ECF of thermoluminescent dosimeters were described In detail. ECFs of 319 reference, control and field dosimeters were measured three times and average of three ECF values was calculated. Also, % CV(Coefficient of Variation) of three ECF values was calculated to verify ECF. ECF & % CV distributions for the field and control dosimeters are presented. TL raw counts of field dosimeters, being used about 6 times for the past 3 years, were almost unchanged, but those of control dosimeters being used more frequently, were degraded about 4.7 %.

• Journal of Radiation Protection and Research
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• v.15 no.2
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• pp.57-65
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• 1990

Newly developed LiF(Mg, Cu, Na, Si) thermoluminescence phosphors sealed in a plastic capsules (32mm dia., 0.9mm wall thickness) were used for in-phantom dosimetry of $^{60}Co$ $\gamma$-irradiation. The absorbed doses in water were determined by applying the general cavity theory to the absorbed dose in TLD cavity, which was computed from exposure. The absorbed doses at various sites in the water-phantom were measured by LiF(Mg, Cu, Na, Si) TLD and compared with doses obtained by the ionization method. Both results were consistent within the experimental fluctuation$({\pm}3%)$ Central axis percentage depth doses and phantom-air ratios measured by LiF(Mg. Cu, Na, Si) TLD showed good agreement with the published values[Br. J. Radiology, Suppl. 17(1983)].

• Journal of Radiation Protection and Research
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• v.1 no.1
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• pp.10-14
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• 1976

Influence of the cavity size on the response of LiF TLD was theoretically investigated for a presumed system of spherical TLD cavity imbedded in a medium of polyethylene. Calculation of the response for different radii of the spherical cavity was carried out as a function of incident photon energy, applying recent cavity theory. The range of the radii covers 1.578 to 6.528 mm, while that of the incident photon energies extends from 0.02 to 3.0 MeV. As a results, the response of the LiF TLD imbedded in a medium as a cavity was found to be functions of its own size as wall as the incident photon energy.

• 대한방사선치료학회:학술대회논문집
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• 2003.03a
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• pp.7-8
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• 2003

• The Journal of Korean Society for Radiation Therapy
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• v.17 no.1
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• pp.57-71
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• 2005

Purpose : To evaluate radiation dose and accuracy with TLD and diode detector when treat total skin with electron beam. Materials and Methods : Using Stanford Technique, we treated patient with Mycosis Fungoides. 6 MeV electron beam of LINAC was used and the SSD was 300 cm. Also, acrylic speller(0.8 cm) was used. The patient position was 6 types and the gantry angle was 64, 90 and $116^{\circ}$. The patient's skin dose and the output were detected 5 to 6 times with TLD and diode. Result : The deviations of dose detected with TLD from tumor dose were CA $+\;6\%$, thigh $+\;8\%$, umbilicus $+\;4\%$, calf $-\;8\%$, vertex $-\;74.4\%$, deep axillae $-\;10.2\%$, anus and testis $-\;87\%$, sole $-\;86\%$ and nails shielded with 4mm lead $+4\%$. The deviations of dose detected with diode were $-4.5\%{\sim}+5\%$ at the patient center and $-1.1\%{\sim}+1\%$ at the speller. Conclusion : The deviation of total skin dose was $+\;8\%{\sim}-\;8\%$ and that deviation was within the acceptable range(${\pm}\;10\%$). The boost dose was irradiated for the low dose areas(vertex, anus, sole). The electron beam output detected at the sootier was stable. It is thought that the deviation of dose at patient center detected with diode was induced by detection point and patient position.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.419-426
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• 2016

The research is done to analyze the change of personal dosimeter according to the elapsed times(24 hours, 1 week, 2 weeks, 3 weeks, 4 weeks) and magnetic field and find out the effective exposure treatment for radiation workers. At first, research the heat treatment and radiation of grouped TLD and keep them in different environments-exposed separately to observe the consequences of glow curve and the level of radiation exposure. As a result, we could find that 24 hours passing TLD group showed the difference in glow curve and the level of radiation. This can be considered as the change caused by magnetic exposure. Also the average radiation exposure level of TLD group, unexposed to the magnetic field, was 15.41 mSv. And the average radiation exposure level of TLD group, exposed to the magnetic field, was 14.83 mSv which decreased the biggest amount(3.80%) among the other groups. If a radiation worker, who works in PET-MRI room, uses TLD as a personal dosimeter, the level of real radiation exposure caused by exposure to the magnetic field won't change significantly as recorded at a regular record cycle but with not regular record but interim record, the lower exposure dose will be appeared than the real level of radiation.

• Journal of Radiation Protection and Research
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• v.24 no.3
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• pp.143-154
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• 1999

Panasonic UD-809P type albedo neutron TL dosimeters mounted on a water phantom were used to measure neutron personal dose equivalent in a Korean nuclear power plant. From the measured TL readings, personal dose equivalents from thermal, epithermal and fast neutrons were evaluated by using a method adopted in a neutron dose calculation algorithm for Panasonic UD-809P type albedo neutron TL dosimeters, which was suggested in a Panasonic TLD System User's Manual. The results showed that personal dose equivalent from fast neutrons could not be adequately evaluated in a field with high thermal neutron fraction to be encountered in a nuclear power plant. This seems to be related to the incomplete incidence of albedo thermal neutrons to the TL dosimeters. In order to evaluate appropriately the personal dose equivalent from fast neutrons in the field condition, new method fer the neutron dose calculation algorithm was suggested. In this new method, neutrons are grouped into thermal neutrons and fast neutrons. For each neutron component, equations for TL response, sensitivity factor, calibration factor and personal dose equivalent were derived.

• Progress in Medical Physics
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• v.20 no.4
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• pp.308-316
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• 2009

To achieve the accurate evaluation of given absorbed dose from output dose of linear accelerator photon beam through investigate the characteristics of LiF:Mg,Cu,P TLD powder. This experimental TL phosphor is performed with a commercial LiF:Mg,Cu,P powder (Supplied by PTW) and TL reader (LTM, France). The TLD was exposed to 6 MV X rays of linear accelerator photon beam with range 15 to 800 cGy in blind dose at two hospitals. The dose evaluation of TLD was through the experimental algorithms which were dose dependency, dose rate dependency, fading and powder weight dependency. The glow curve has shown the three peaks which are 110, 183 and 232 degrees of heating temperature and the main dosimetric peak showed highest TL response at 232 high temperature. In this experiments, the LiF:Mg,Cu,P phosphor has shown the 2.5 eV of electron trap energy with a second order. This experiments guided the dose evaluation accuracy is within 1% +2.58% of discrepancy. The TLD powder of LiF:Mg,Cu,P was analyzed to dosimetric characterists of electron captured energy and order by glow shape, and dose-TL response curve guided the accuracy within 1.0+2.58% of output dose discrepancy.

• Journal of Radiation Protection and Research
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• v.37 no.2
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• pp.96-102
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• 2012

International Commission on Radiological Protection (ICRP) has revised its recommendations concerning the tissue reaction to ionizing radiation in accordance with consideration of the detriment arising from non-cancer effects of radiation on health based on recent epidemiological basis. Particularly, for the lens of the eye, the threshold in absorbed dose revised to be 0.5 Gy, for occupational exposure in planned exposure situation the commission recommended "An equivalent dose limit for the lens of the eye of 20 mSv in a year, averaged over defined periods of 5 years, with no single year exceeding 50 mSv." To monitor the radiation exposure of radiation worker, TLD is typically provided and the lens of eye dose can be assessed by run of dose calculation algorithm with TL element response data. This study is to assess equivalent dose of the lens of eye using the Harshaw TLD system and its two different dose calculation algorithms. The result provides the Harshaw TLD system showed the assessment of the lens of eye dose with 48.84% error range.

• Progress in Medical Physics
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• v.17 no.4
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• pp.187-191
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• 2006

The purpose of this study was to measure the dose distribution from the moving phantom for the respiratory motion. The phantom for TLD measurement was designed and built for this study based on the multiple plates for placing TLD and film. The TLDs may be inserted at 3 mm intervals in each TLD plate. For the measurements, TLD plate was inserted into the phantom at 1.5 cm ($d_{max}$) depth, and phantom was allowed to move in SI directions in the range of 1 to 2 cm with 0.5 cm interval for 6 MV X-ray beams. Penumbra and FWHM were measured at both moving state and compared stationary. It was found that penumbra increased 0.71 cm at stationary and 2.10 cm at moving state in 2 cm movement, and that FWHM are 7.52 cm for stationary state and 7.02 cm for moving state (2 cm movement). In this study, film was used to compared with TLD results of measurements and simitar results were observed. Therefore, it is expected that TLD moving phantom may be useful for the treatment of tumors that move due to the respiratory motion.