• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.220-221
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• 2009

• Journal of Radiation Protection and Research
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• v.18 no.1
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• pp.1-7
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• 1993

In its recent recommendation No. 60(1990), ICRP has newly introduced several terminology which had not existed in its prior recommendation No. 26(1977). Of these, a newly defined quantity 'Equivalent Dose' replacing the 'Dose Equivalent' of the ICRU concept has been recommended to be adopted in the radiation protection programme. However, since the committee still uses the 'Dose Equivalent' and 'Equivalent Dose' in its several publications, it is likely to provoke unnecessary confusions and misuses in applying these two quantities. In this paper were described the definition and difference between these two quantities to help in understanding of these two quantitites among the person involved in the radiation protection activities.

• 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.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.283-289
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• 2015

Recently, high energy photon radiotherapy is a growing trend for increasing therapy results. Commonly, if you use high energy photons above 6~8 MeV nominal accelerator voltage, It lead the photo-nuclear reaction and the generation of photo-neutron are accompanied and these problematic factors are issued in the view of radiation protection. Therefore, in this study analyzed for dose distribution of photo-neutron in radiotherapy room based on MCNPX. As a result, absorbed dose is increased sharply from 10 MV to 12 MV. It was founded that the rapid increasement of photoneutron fluence was related to the absorbed dose at above 10 MV. Also, in case of the recommendation of ICRP 103, the outcome of an exchanged equivalent dose which based on calculated an absorbed dose, showed lower equivalent dose than ICRP 60 by reflecting the contribution of secondary photon for absorbed dose of human body in the low energy band.

• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.41-46
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• 2008

To estimate the finger dose absorbed by $^{99m}Tc$ injection, simulations are carried out to calculate the dose equivalent of each finger per second with radioactivity of 370 MBq, based on the GEANT4 simulator. For the $^{99m}Tc$ source of the volume of 0.4mL and the radioactivity of 370 MBq, we obtained the dose equivalent of the right thumb ($0.29\;{\mu}Sv{\cdot}sec^{-1}$), the right index finger ($1.19\;{\mu}Sv{\cdot}sec^{-1}$), the right middle finger ($1.07\;{\mu}Sv{\cdot}sec^{-1}$), the left thumb ($4.36\;{\mu}Sv{\cdot}sec^{-1}$), and the left index finger ($3.37\;{\mu}Sv{\cdot}sec^{-1}$), respectively. This simulation results may serve as a useful data in the prediction of finger dose absorbed by $^{99m}Tc$ injection.

• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.47-58
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• 1997

The conversion coefficients of effective dose per unit air kerma and equivalent dose per unit fluence were calculated by MCNP4A code for antero-posterior(AP) and postero- anterior(PA) incidence of broad, unidirectional beams of photons into anthropomorphic MIRD phantom. Calculations have been performed for 20 monoenergetic photons of energy ranging from 0.03 to 10 MeV. The conversion coefficients showed a good agreement with the corresponding values given in the draft publication of joint task group of ICRP and ICRU within 10%. The deviations may arise from the differences of geometry in the MIRD phantom and the ADAM/EVE phantoms, and the differences in the codes and cross-section data used. Inclusion of a specific oesophagus model results in effective dose slightly different(5% at most) from the effective doses obtained by adopting the equivalent doses for the thymus or pancreas. Deletion of the ULI from the remainder organ appeared not to be significant for the cases of photon dosimetry covered in this study.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.57-62
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• 2010

Maintenance on the water chamber of steam generator, the change of pressurizer heater, the removal of pressure tube feeder, and so on during outage in nuclear power plants (NPPs) has a likelihood of high radiation exposure to whole body of workers even short time period due to the high radiation exposure rates. In particular, it is expected that hands would receive the highest radiation exposure because of its contact with radiation materials. In this study, field tests on extremity dose assessment of radiation workers for contact works with high radiation exposure were conducted during the maintenance periods in Korean pressurized water reactors (PWRs) and pressurized heavy water reactors (PHWRs). In this field test, radiation workers were required to wear additional TLDs on the back and wrist, and an extremity dosimeter on fingers including a main TLD on the chest, while performing maintenance. As a result, it was found that the equivalent dose for fingers was distributed in the fixed range of deep dose and the equivalent dose for wrists.

• Nuclear Engineering and Technology
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• v.3 no.3
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• pp.155-160
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• 1971

Average and effective energies for 239Pu-Be, 241Am-Li and 241Am-F neutron sources have been calculated from a number of published data for the neutron spectra and for the dose equivalent as a function of neutron energies by a numerical method. Also a calculation of the dose equivalent conversion factors, i. e., the first collision dose equivalent and the surface (or multicollision) dose equivalent that equals the product of surface-absorbed dose and a corresponding quality factor, per unit fluence of neutrons from these sources has been carried out in the same way as before. The results are as follows : 1. for average energies 4.07$\pm$0.33, 0.42 and 1.41 MeV； 2. for effective energies based on the concept of the first collision process in the human body 4.45$\pm$0.344, 0.51 and 1.47 MeV; 3. for effective energies based on the concept of the multi-collision process in the human body 4.50$\pm$0.36, 0.50 and 1.45 MeV； 4. for fluence-first collision dose equivalent conversion factors (2.74$\pm$0.07)10$^{-8}$ , 1.58$\times$ 10$^{-8}$ and 2.34$\times$10$^{-8}$ rems/(n/$\textrm{cm}^2$); and 5. for fluence-surface dose equivalent conversion factors (3.55$\pm$0.09)10$^{-8}$ , 2.19$\times$10$^{-8}$ and 2.82$\times$10$^{-8}$ rems/(n/$\textrm{cm}^2$) : respectively.

• The Journal of Korean Society for Radiation Therapy
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• v.29 no.1
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• pp.93-101
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• 2017

Purpose: In breast cancer radiotherapy, brass mesh bolus has been recently studied to overcome disadvantage of conventional bolus. The purpose of this study is to investigate the stability of first introduced the brass mesh in the country, and evaluate the skin surface dose of that. Materials and Methods: The measurement of skin surface dose was evaluated to verify similar thickness of the Brass mesh bolus that compared conformal tissue equivalent bolus with 5 mm thickness. We used 6 MV photons on an ELEKTA VERSA linear accelerator and optically stimulated luminescent dosimeter (OSLD). In addition, two opposed beam using IMRT phantom was applied to comparative study of brass mesh bolus between tissue equivalent bolus. Results: The results showed that similar thickness of the Brass mesh bolus was 3 mm compared with 5 mm tissue equivalent bolus by measuring the skin surface dose of solid phantom. The surface dose for IMRT thorax phantom using 3 mm brass mesh bolus was about 1.069 times greater than that using tissue equivalent bolus. Conclusion: In this study, we found that the brass mesh bolus improved better reduction of skin sparing effect and dose uniformity than tissue equivalent bolus. However evaluation for various clinic cases should be investigated.

• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.35-42
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• 2003

Methodology for calculating the organ equivalent doses and the effective doses of pediatric and adult patients undergoing medical X-ray examinations were established. The MIRD-type mathematical phantoms of 4 age groups were constructed with addition of the esophagus to the same phantoms. Two typical examination procedures, chest PA and abdomen AP, were simulated for the pediatric patients as well as the adult as illustrative examples. The results confirmed that patients pick up approximate 0.03 mSv of effective dose from a single chest PA examination, and 0.4 to 1.7 mSv from an abdomen AP examination depending on the ages. For dose calculations where irradiation is made with a limited field, the details of the position, size and shape of the organs and the organ depth from the entrance surface considerably affect the resulting doses. Therefore, it is important to optimize radiation protection by control of X-ray properties and beam examination field. The calculation result, provided in this study, can be used to implement optimization for medical radiation protection.