• Journal of radiological science and technology
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• v.32 no.2
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• pp.205-212
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• 2009

The response correction factor ( h) is a factor to convert the response of the chamber in solid phantom to the response in water. In RW3 solid phantom, the dependency of beam quality and depth for high energy X-rays are known characteristics, however the dependency of field size, SSD, and chamber type are unknown. In this work we have studied the unknown characteristics on the dependency of response correction factor. The farmer type chamber (FC65G) and small chamber (CC13) were used and two beam qualities of 6 and 15 MV were evaluated. The measured response correction factors at the depth of 5 cm and 10 cm were h = 1.015 and 1.021 for 6 MV X-rays, and h = 1.024 and 1.029 for 15 MV X-rays. In conclusion the response correction factor did not depend on the field size and SSD while depending on the beam quality and depth. In the chambers, there are small differences between the two chambers used in this study but we think additional study for more chambers should be required. The results in this study can be used for analyzing the measured values from ionization chamber dosimetry in RW3.

• Journal of the Korean Society of Radiology
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• v.8 no.4
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• pp.181-187
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• 2014

The purpose of this study were to analyze the characteristic of the glow curves in order to the glow temperature of the thermoluminescent dosimeters (TLDs) for the absorbed dose measurement of the radiation therapy. In this study, we was used the TLDs of the LiF:Mg${\cdot}$Ti, LiF:Mg${\cdot}$Cu${\cdot}$P, $CaF_2$:Dy, $CaF_2$:Mn (Thermo Fisher Scientific Inc., USA). The source-to-solid dry phantom (RW3 slab, IBA Dosmetry, Germany) surface distance was set at 100 cm, and the exposure dose of 100 MU (monitor unit) was used 6- and 15-MV X-rays, and 6- and 12-MeV electron beams in the reference depth, respectively. After the radiations exposure, we were to analyze the glow curves by using the TL reader (Hashaw 3500, Thermo Fisher Scientific Inc., USA) at the fixed heating rate of $15^{\circ}C/sec$ from $50^{\circ}C$ to $260^{\circ}C$. The glow peaks, the trapping level in the captured electrons and holes combined with the emitted light, were discovered the two or three peak. When the definite increasing the temperature of the TLDs, the maximum glow peak representing the glow temperature was follow as; $LiF:Mg{\cdot}Ti$: $185.5{\pm}1.3^{\circ}C$, $LiF:Mg{\cdot}Ti$: $135.0{\pm}5.1^{\circ}C$, $CaF_2$:Dy: $144.0{\pm}1.6^{\circ}C$, $CaF_2$:Mn: $294.3{\pm}3.8^{\circ}C$, respectively. Because the glow emission probability of the captured electrons depend on the heating temperature after the exposure radiation, TLDs by applying the fixed heating rate, the accuracy of measurement will be able to improve within the absorbed dose measurement of the radiation therapy.