• The Journal of Korean Society for Radiation Therapy
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• v.19 no.1
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• pp.7-17
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• 2007

Purpose: As increasing complexity of modern radiotherapy technique, more developing dosimetry is required. Polymer gel dosimeters offer a wide range of potential applications with high resolution and assured quality in the thee-dimensional verification of complex dose distribution such as intensity-modulated radiotherapy (IMRT). The purpose of this study is to find the most sensitive and suitable gel as a dosimeter by varying its composition ratio and its condition such as temperature during manufacturing. Materials and Methods: Each polymer gel with various ratio of composition was irradiated with the same amount of photon beam accordingly. Various polymer gels were analyzed and compared using a dedicated software written in visual C++ which converts TE images to R2 map images. Their sensitivities to the photon beam depending on their composition ratio were investigated. Results: There is no dependence on beam energy nor dose rate, and calibration curve is linear. Conclusion: The polymer gel dosimeter developed by using anti-oxidant in this study proved to be suitable for dosimetry.

• Journal of radiological science and technology
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• v.34 no.2
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• pp.157-163
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• 2011

Recently a variety of high technologies for radiation therapy (IMRT, SRS,. 3D-RT, etc.) has been developed. For the cervical and rectal cancer, 3field or 4field radiotherapy have been applied to the patients. In the case of two-dimensional treatment, one of the most typical side-effects is skin burn due to the radiation irradiation. In general the skin dose is evaluated by only a single measurement during the whole treatment period. In this study, however, skin dose was measured in each radiation treatment and the total skin dose was accumulated in a glass dosimeter through all the cases. After simulating the skin dose from treatment planning system, the results were compared with the actual skin doses. The results showed a good agreement between two data sets. Even though there are certain amount of errors caused by the patient movement along the treatment, the difference between actual dose and simulated dose was within the accepted range of error.

• Journal of the Korean Society of Radiology
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• v.16 no.4
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• pp.471-476
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• 2022

The purpose of this study was to study the probability of cancer occurrence due to photoneutron dose exposure of the colon and thyroid gland, which are normal organs, in 3D CRT, IMRT 5 portals, and IMRT 9 portals, which are radiotherapy methods for prostate cancer. The total prescribed dose for prostate cancer was 6600 cGy, 220 cGy per dose, and 30 divided irradiations were applied for the total number of times. After setting up the Rando phantom on the treatment table (couch) of the medical linear accelerator used in the experiment, an optically stimulated luminescence albedo neutron dosimeter was placed on the corresponding area of the large intestine and thyroid gland of the phantom for measurement. During 3D CRT of prostate cancer, the probability of secondary cancer due to photoneutron dose to the colon and thyroid gland, which are normal organs, was 1.8 per 10,000 people. And IMRT 5 portals were 8.7 per 10,000 people, which was about 5 times larger than 3D CRT. IMRT 9 portals derived the result that there is a probability that 1.2 people per 1,000 people will develop cancer. Based on this study, the risk of secondary radiation exposure due to the dose of photoneutrons generated during radiation therapy is studied, and it is thought that it will be used as useful data for radiation protection in relation to the stochastic effect of radiation in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.739-744
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• 2013

The aim of this study is to evaluate the noise level from the machines used for tunnel construction and to analyze the noise exposure level of workers engaged in tunneling works. The sound level meter and noise dosimeters was used for the monitoring of noise in the tunneling work sites. The average noise from jumbo drill was 113.0 dE(A), the noise from pay loader was 92.4 dB(A), the noise from backhoe was 99.9 dB(A) and the noise from shotcrete machine was 94.3 dE(A). The tunneling workers were exposed to 66.9~94.9 dB(A) of noise and other workers exposed to less than 90 dB(A) of noise. Jumbo drill operators were exposed to to 82.5~84.2 dB(A) of noise, backhoe operators were exposed to 70.2~94.9 dB(A) of noise, shotcrete machine operators were exposed to 68.2~74.7 dB(A) of noise and pay loader operators were exposed to 59.2~81.3 dE(A) of noise.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.909-916
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• 2019

Radiation therapy of oral and head and neck cancers often involves skin in the therapeutic range, and the use of bolus is frequently used. Dose irregularities provide dose uncertainty in patient application. In this study, the physical properties of patients with gel bolus, poly lactic acid (PLA), and silicon using 3D printing were fabricated. Dose uncertainties arising from the actual radiation dose delivery were measured. As a result, PLA bolus was stable in the Common irregularities. Silicon bolus may be useful for patients with severe irregularities or frequent changes in patient's body shape.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.39-41
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• 2004

This paper demonstrates the in-house development of the subsystem C&DH in a D-SAT satellite project of Astronautic Technology (M) Sdn. Bhd. (ATSB). D-SAT is a non-imaging satellite. It will carry a dosimeter as the payload for scientific objectives. Since one of the D-SAT project establishment intended objectives is to demonstrate the research and development skill of the ATSB engineers on the satellite system building, most of the subsystems of the D-SAT are developed in-house including the C&DH subsystem. C&DH subsystem plays an important role for managing data handling tasks and general operation of the satellite system. The C&DH development includes the research and study on the hardware and software design, the design of both the hardware and software, the development of the software system, the integration between the software and the hardware system and the implementation of the subsystem into the satellite system. This program allows ATSB to accomplish the engineers with expertise not only in the C&DH subsystem but other subsystems too besides developing knowledge in the management of a space project that covers not only on the technical issues but issues relating to the economic, political and legal issues.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.391-397
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• 2016

Stereotactic body radiotherapy is effective technic in radiotherapy for low stage lung cancer. But lung cancer is affected by respiratory so accurately concentrate high dose to the target is very difficult. In this study, evaluated the target volume according to how to take the image. And evaluated the dose by photoluminescence glass dosimeter according to how to contour the volume and respiratory range. As a result, evaluated the 4D CT volume was 10.4 cm3 which was closest value of real size target. And in dose case is internal target volume dose was 10.82, 16.88, 21.90 Gy when prescribed dose was 10, 15, 20 Gy and it was the highest dose. Respiratory gated radiotherapy dose was more higher than internal target volume. But it made little difference by respiratory range. Therefore, when moving cancer treatment, acquiring image by 4D CT, contouring internal target volume and respiratory gated radiotherapy technic would be the best way.

• Journal of the Korean Society of Radiology
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• v.6 no.6
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• pp.465-471
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• 2012

In this study, three dimensional X-ray dose distribution from dental X-ray generator system was measured by ALOKA PDM-117 dosimeter. The X-ray dose distribution will be change with XCP-DS FIT in oral shot, because the distance between X-ray generator and the dosimeter. The X-ray dose change affects on patient exposure and radiograph image quality. Therefore, it is important to obtain relation between the X-ray dose and the distance. The X-ray dose at the central position was decreased with increasing the distance. Furthermore, the dose at the edge of the X-ray flux was increased with increasing the distance. The increased dose affects on the patient radiation exposure. The present results will provide for good dental radiograph image and reducing radiation over-exposure on patient.

• Journal of radiological science and technology
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• v.45 no.4
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• pp.313-320
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• 2022

Both angiography and interventional procedures accompanied by angiography provide many diagnostic and therapeutic benefits to patients and are rapidly increasing. However, unlike general radiography or computed tomography using the same X-ray, the amount of radiation is quite high, but the dose range can vary considerably for each patient and operator. The high sensitivity of the lens to radiation during cerebral angiography and neurointervention is already well known, and although there are many related studies, it is insufficient to easily reduce radiation in diagnosis and treatment. In this situation, in particular, by adding three-dimensional rotational angiography (3D-RA) to the existing two-dimensional (2D) angiography, it is now possible to make an accurate diagnosis. However, since this 3D-RA acquires images through projection of more radiation than before, the exposure dose of the lens may be higher. Therefore, we tried to analyze whether the radiation dose of the lens can be reduced by moving the lens out of the field range by adjusting the table height and magnification ratio during the examination using 3D-RA. The surface dose was measured using a rando phantom and a radiophotoluminescent glass dosimeter (PLD) and the radiation dose was compared by adjusting the table height and magnification ratio based on the central point. As a result, it was found that the radiation dose of the lens decreased as the table height increased from the central point, that is, as the lens was out of the field of view. In conclusion, in 3D-RA, moving the table position of about 2 cm in height will make a significant contribution to the dose reduction of the lens, and it was confirmed that adjusting the magnification ratio can also reduce the surface dose of the lens.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.9
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• pp.831-840
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• 2013

The noise levels of workers in tunnel sites are likely to be high because tunneling work places are confined space. However, research on the noise exposure levels of tunneling workers have not been performed intensively due to restricted accessibility to tunnel construction sites. The aim of this study is to evaluate the noise exposure levels for workers engaged in tunneling work sites. Noise dosimeters were used for monitoring workers' noise exposure level in 5 tunneling work sites in accordance with the Notification of the Ministry of Labor. Among 5 tunneling work sites, 4 of them used NATM tunneling method and 1 work site used shield TBM tunneling method. The average noise exposure levels of NATM tunneling workers was 81.1 dB(A) and 15.4 % of the workers' noise level were exposed more than 90 dB(A) which is the exposure limit value. In Shield TBM tunneling method, 4.3 % of the workers were exposed more than 90 dB(A) of noise level, the average noise exposure levels of TBM tunneling workers was 84.1 dB(A).