| Home | E-Submission | Sitemap | Contact Us |  
top_img
J. Radiat. Prot. Res > Volume 47(4); 2022 > Article
Lee, Kim, Kye, Lee, Jo, Lee, Kim, and Kang: Development of Self-Questionnaire for Internal Dose Assessment by Food Ingestion

Abstract

Background

The accident at the Fukushima Daiichi nuclear power plant increased the level of anxiety related to the radioactive contamination of various foods sourced in Japan. Particularly, after the accident, the detection of artificial radionuclides in locally produced foods raised food safety concerns. In this study, the radioactivity concentrations and annual ingestions of 40K and 137Cs in food products commonly and frequently consumed by the general public were investigated, and the annual effective dose of each was evaluated.

Materials and Methods

The 2016–2018 data from the Radiation Safety Management Report released by the Korea Nuclear Safety Technology Center was referenced for the evaluation of the amounts of 40K and 137Cs contained in food. Using the food-ingestion survey mentioned above as a reference, we selected 62 foods to include in our radioactivity concentration and dose assessment. We also developed a questionnaire and evaluated the responses from the subjects who answered the questionnaire.

Results and Discussion

The radioactivity concentration of 137Cs was found to be close to or below the level of minimum detectable activity. Additionally, the annual ingestion of 62 foods was 294.77 kg/yr, the effective doses from 40K and 137Cs were 136.4 and 0.163 μSv/yr, respectively.

Conclusion

Thus, the findings confirmed that the effective dose from 40K and 137Cs in food tends to be lower than the effective dose limit of 1 mSv/yr suggested by the International Commission on Radiological Protection (ICRP) Publication 60. The questionnaire developed in this study is expected to be useful for estimating the annual effective dose status of Korean adults who consume foods containing 40K and 137Cs.

Introduction

Before the Fukushima Daiichi nuclear accident, the domestic provisional permissible standard for radioactivity concentration in foods was zero for radioactive iodine (131I), 100 Bq/kg for baby foods, dairy products, and processed dairy products, and 300 Bq/kg for other foods. Additionally, radioactive cesium (i.e., 134Cs and 137Cs) was regulated to a maximum of 370 Bq/kg for all foods. However, after the Fukushima accident, the domestic maximum acceptable concentration of radioactive cesium (134Cs and 137Cs) was changed to 100 Bq/kg for all Japan-sourced foods [1]. The effective dose limit for general artificial radiation, according to the International Commission on Radiological Protection (ICRP) Publication 60, is 1 mSv/yr. This value is the acceptable limit for the total internal and external radiation exposure from foods. Most of this internal and external radiation exposure is known to be attributable to the 40K content within food products [2]. Potassium-40 is a natural radionuclide and an essential element for the human body. In contrast, 137Cs emits gamma rays that are present in the environment in the form of radioactive fallout from nuclear experiments and accidents at nuclear power plants; thus, the evaluation of 137Cs is critical in internal exposure assessments. Human exposure to radionuclides via the ingestion pathway is typically associated with the radionuclide content in the soil, uptake/absorption of nutrients and minerals by plants, chemical properties of the soil, and consumption rates of a particular foodstuff [3, 4]. Considering the various influences, it is important to analyze the presence of radioactive materials in foodstuffs, especially in staple foods, thus gaining insights into their potential effects on humans. Moreover, such analysis provides data on natural radioactivity in crops, providing a reliable basis for dose estimation [5]. Direct measurement of body radioactivity using a whole-body counter is the most reliable method for monitoring the internal exposure of workers and members of the public [6]. However, research on the evaluation of commonly ingested foods is lacking. It is also important to note that differences in the radioactivity concentrations of 40K in the human body may be related to eating habits, and an assessment of food intake is also required for the accurate interpretation and analysis of 40K measurements. A food-based food intake frequency questionnaire has been developed; however, it is mainly for nutrients and foods related to specific diseases or medical conditions such as hypertension and cancer. Therefore, the questionnaire is not suitable for internal exposure evaluation [7, 8]. Considering the two types of radiation safety management reports published by the Korea Institute of Nuclear Safety (KINS) and the Korea National Health and Nutrition Examination Survey (KNHANES), we conducted a food radioactivity and intake frequency survey for the purpose of calculating national statistical data and procuring evidence for policy formulation and evaluation [911]. Only the types of foods and radioactive substances consumed by the public are investigated, and the annual effective dose from food intake was no evaluated. Furthermore, although it is a standard practice to measure the radioactivity concentrations of foods, the domestic approach to investigating the relationship between the internal radiation dose and food intake is inadequate compared to that of developed countries.
Thus, in this study, we investigated the radioactivity concentrations of 40K and 137Cs in foods consumed in South Korea from the perspective of annual intake and evaluated the internal radiation dose. We also developed a self-questionnaire that can be used to facilitate the evaluation of the extent to which daily food intake contributes to the internal radiation dose. We propose the use of our self-questionnaire for the purpose of evaluating the food intake-related internal radiation dose assessment for whole-body counter testers.

Materials and Methods

1. Internal Exposure Evaluation Method

Internal exposure refers to the exposure of body tissues to radioactive substances via inhalation, ingestion, skin absorption, etc. ICRP Publication 60 requires that the consequences of internal exposure, as well as the extent of external exposure, be measured and inclusively evaluated [12]. The internal radiation dose evaluation method has been classified into direct and indirect bioassay methods. The direct bioassay method entails the use of an external measurement system (e.g., a whole-body counter or a lung counter) to directly measure the radioactivity of radionuclides existing in the human body. As previously mentioned, according to ICRP Publication 60, the effective dose limit for artificial radiation is 1 mSv/yr, which is the sum of the internal and external exposure values from foods [12]. The annual effective dose is used to assess body exposure from food intake. The sensitivity of human body to radiation depends on the type of radioactive nuclide in the food and the exposed tissue. The radioactivity concentrations of 40K and 137Cs in food and the annual food ingestion of Korean adults from 2016 to 2018 are excluded from the data on sensitivity of human tissues according to the conversion factor presented by the ICRP Publication 119 (2012); the values are 6.2×10−9 Sv/Bq and 1.3×10−8 Sv/Bq, respectively [12]. Then, the internal exposure dose is calculated using the following formula:
D=f×C×U
where D is the internal exposure dose (Sv/yr), f is the nuclide dose conversion coefficient (Sv/Bq), C is the nuclide radioactivity (Bq/kg), and U is the annual intake (kg/yr). For the radioactivity of 40K and 137Cs in food, data from 2016 to 2018 procured by KINS (“Marine Environmental Radioactivity Survey” and “Environmental Radioactivity Survey data in Korea”) and the Korea Institute of Health and Environment were taken as references [911, 13, 14]. The KINS report is a collection of materials that are compiled and published according to food radioactivity values obtained directly from 15 local radioactivity measuring stations across the country. The Disease Control Agency conducts a national health and nutrition survey every year and provides statistical data on food and nutrient intakes of people. For the annual food intake, the materials for consumption food intake from the 7th period (2016 to 2018) data of the National Health and Nutrition Examination Survey were applied.

2. Development of Self-Questionnaire

The items on the self-questionnaire were classified into two categories. The first category consisted of physical condition and basic health check items (e.g., disease history, smoking status, and physical activity level); the second category consisted of food-intake frequency questions for common foods. Current methods employed to evaluate food intake include diet recording methods, 24-hour recall methods, and food frequency questionnaire methods; each of these types of surveys serves a different research purpose [15]. Food-intake frequency survey methods are useful for investigating the relationship between food consumption and diseases that affect the relevant population, as they provide the information about long-term eating habits; however, the level of accuracy of the evaluation is not high [16]. Researchers in many foreign countries, including the United States, have developed and used many food-intake frequency surveys for the primary purpose of studying nutrients that are closely related to health and chronic illness [17]. Because food-intake frequency surveys evaluate a subject’s intake of a limited variety of foods, the list must reflect the dietary characteristics of the subject. There is no separate food intake frequency questionnaire for the current internal dose evaluation. We used a list of commonly consumed foods procured via the food intake survey data of 24,629 subjects in the 7th KNHANES (2016–2018), which were the latest data available at the time of the study. Based on the KINS Radiation Safety Management Report, we used a list of highly radioactive and consumable foods. To determine the standard average intake per person, we referred to the data obtained from the food-intake frequency survey of the 7th KNHANES (2016–2018). For each food, the subjects were given nine self-declaration options for the average frequency of food intake over the previous month: rarely, once a month, 2–3 times a month, once a week, 2–4 times a week, 5–6 times a week, once a day, twice a day, or three times a day. The self-questionnaire was used with whole-body counter examinations.

Results and Discussion

As mentioned, the results of the 7th KNHANES on the radioactivity and annual intake of commonly-consumption foods that was developed and administered by KINS were used to evaluate and quantify the contributions of 62 foods to the internal radiation dose in humans. Specifically, we developed a self-questionnaire that included a food-intake frequency survey.

1. Internal Exposure Evaluation

Table 1 shows the average radioactivity concentrations of 40K and 137Cs in the 62 foods analyzed in the 2016–2018 data. Among the 62 food data, the radioactivity concentration range of 40K was from 24.0 to 1,310 Bq/kg-fresh, and that of 137Cs from MDA (minimum detectable concentration) to a maximum of 781 mBq/kg-fresh. Regarding the radioactivity concentrations according to food, the 40K content was the highest in kelp and coffee, relatively high in seaweeds (Gracilaria sp., Hijikia fusiforme, and sea lettuce), and lowest in rice cake and rice. The 137Cs content was highest in coffee and A. bisporus, and relatively high in root plants (lettuce, beans, carrots). Among the 62 foods, rice, milk, and kimchi were associated with the highest annual intake, whereas Gracilaria species and mackerel were associated with the lowest annual intake. Table 2 shows the 40K and 137Cs internal radiation dose results according to the food type. The foods with a 40K high internal radiation dose were coffee, kimchi, and green tea, whereas the foods with low internal radiation doses were pen shell clams and horse mackerel. In the case of 137Cs, the internal radiation dose was the highest for coffee and radish, whereas it was lowest for the pen shell and Gracilaria sp. For some foods, such as kimchi and sesame leaves, the concentration of 137Cs was extremely low; therefore, the internal radiation dose could not be evaluated. The total intake of all of 62 foods was 294.77 kg/yr; additionally, the total internal radiation dose from 40K was 136.4 μSv/yr. The total internal radiation dose from 137Cs was 0.163 μSv/yr, which is extremely low compared to the annual 40K dose. Thus, we confirmed that the annual internal radiation dose from 137Cs was lower than the effective dose limit of 1 mSv/yr recommended by ICRP Publication 60. The total annual effective dose from 40K in foods mainly consumed in Korea, as determined in this study, was lower than that reported for Iran (5,240 μSv/yr) [18] and similar to that for Japan (130–217 μSv/yr) [19]. The total annual effective dose from 137Cs in foods mainly consumed in Korea, as reported in this study, was lower than that reported in Iran (2,490 μSv/yr) [18] as well as Japan (49–378 μSv/yr) [19].

2. Self-Questionnaire

Based on the evaluation results of the 40K and 137Cs radioactivity concentrations in foods (Table 1) and the internal radiation dose due to food intake (Table 2), commonly consumed foods in South Korea were classified into food groups. We developed a self-questionnaire to evaluate the internal radiation dose directly resulting from the ingestion of food. Appendix 1 presents the self-questionnaire. The areas of focus of the self-questionnaire include the physical condition of the subject, disease history, smoking status, and level of physical activity, all of which are covered in a basic health examination. For the food-intake frequency survey, the foods are presented in food groups (i.e., grains, beans, tubers, and nuts; vegetables; fruits and mushrooms; meat; seafood and seaweed; and coffee, tea, dairy products, and other foods). Some subjects were offered the option to list and provide information regarding foods that they frequently consume but are not listed in the survey. This information can be used to evaluate the annual internal radiation dose attributable to the non-listed food(s) through the analysis of the radioactivity concentration(s) in future investigations. To help the subjects visualize a single serving, a picture of a paper cup was added to the food-intake survey sheet. The survey sheet states that the capacity of the paper cup corresponds to 100 g of each food product. Because there may be inter-individual differences in the amount of food consumed in one meal, we chose to classify and present three or four amount options in the food-intake frequency survey. Specifically, after the 100-g serving size was defined, depending on the food, the survey options were grouped as either 1/2, 1, 1½, and 2 or 1/8, 1/4, and 1/2.

Conclusion

In this study, we investigated the radioactivity concentrations of 40K and 137Cs, as well as their annual internal dose via intake of frequently and commonly consumed foods. The annual intake and annual effective dose from 40K were much higher than those from 137Cs. Because the chemical and metabolic characteristics of K and Cs are similar, the distributions of 40K and 137Cs in the most frequently consumed foodstuffs in Korea show similar trends. The annual intake and radioactivity concentrations were evaluated by referring to the materials of the 7th KNHANES (2016–2018) on food intake and the 2016–2018 Radiation Safety Management Report released by KINS. Using the food-intake survey mentioned above as a reference, we selected 62 foods to include in our radioactivity concentration and internal radiation dose evaluations. We also developed an internal exposure self-questionnaire, which includes a food-intake frequency questionnaire, for the purpose of internal radiation dose evaluation. The questionnaire consists of 26 items, including basic health check-up items. In the food-intake frequency questionnaire, the subjects were offered the following options regarding the frequency of food eaten over the period of the previous month: rarely, once a month, 2–3 times a month, once a week, 2–4 times a week, 5–6 times a week, once a day, twice a day, and three times a day. However, more extensive studies are necessary to elucidate the effects of 40K and 137Cs in the human body after their ingestion via foods, as the radioactivity concentration in food may affect the concentration in the body. Statistical analysis should be conducted to derive the relationship between food ingestion and radioactivity concentration in the body. In addition, it is expected that the dose assessment questionnaire developed in this study can be used for epidemiological studies that are purposed to better understand the daily food ingestion of Korean adults and to evaluate the annual effective dose of consumed foods.

Acknowledgements

This work was supported by a Dongnam Institute of Radiological & Medical Sciences (DIRAMS) grant funded by the Korean government (MSIT) (No. 50492-2022).

NOTES

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Author Contribution

Conceptualization: Kang YR, Kim JK, Lee CG, Lee JE. Data Curation: Kim HJ, Kye YU, Lee DY, Kang YR. Writing of the original draft: Kang YR, Kim JK, Lee CG, Lee JE. All the authors have proofread the final version.

References

1. Korea Ministry of Food and Drug Safety. Information of food radioactivity safety management [Internet]. Cheongju, Korea, Ministry of Food and Drug Safety. c2021;[cited 2022 Jun 1]. Available from: http://www.foodsafetykorea.go.kr/foodcode .

2. International Commission on Radiological Protection. 1990 Recommendations of the International Commission on Radiological Protection (ICRP Publication 60). Ann ICRP. 1991;21(1–3):1-201.

3. Hassan YM, Zaid HM, Guan BH, Khandaker MU, Bradley DA, Sulieman A, et al. Radioactivity in staple foodstuffs and concomitant dose to the population of Jigawa state, Nigeria. Radiat Phys Chem. 2021;178:108945.
crossref
4. Lee JS, Jo YI, Kang YR, Kye YU, Il P, Lee DY. Filament material evaluation for breast phantom fabrication using three-dimensional printing. Nucl Technol Radiat Prot. 2020;35(4):372-379.
crossref
5. United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation (Annex B: Exposures from natural radiation sources) [Internet]. New York, NY, United Nations Scientific Committee on the Effects of Atomic Radiation. 2000.

6. Ramzaev V, Ishikawa T, Hill P, Rahola T, Kaidanovsky G, Yonehara H, et al. Intercomparison of whole-body counters by using a subject who had incorporated 137Cs into the body. Radiat Prot Dosimetry. 2002;98(2):179-189.
crossref pmid
7. Kim MK, Yun YM, Kim YO. Developing dish-based food frequency questionnaire for the epidemiology study of hypertension among Korean. Korean J Community Nutr. 2008;13(5):701-712.

8. Park MK, Kim DW, Kim J, Park S, Joung H, Song WO, et al. Development of a dish-based, semi-quantitative FFQ for the Korean diet and cancer research using a database approach. Br J Nutr. 2011;105(7):1065-1072.
crossref pmid
9. Korea Institute of Nuclear Safety. 2016–2018 Marine environmental radioactivity survey (KINS/ER-092). Daejeon, Korea, Korea Institute of Nuclear Safety. 2012.

10. Korea Institute of Nuclear Safety. 2016–2018 Environmental radioactivity survey data in Korea (KINS/ER-028). Daejeon, Korea, Korea Institute of Nuclear Safety. 2020.

11. Korea Centers for Disease Control and Prevention. Korea National Health and Nutrition Examination Survey (KNHANES VII-1-3) 2016-2018 [Internet]. Cheongju, Korea, Korea Health Industry Development Institute. 2019;[cited 2022 Jun 1]. Available from: https://www.khidi.or.kr/kps/dhraStat/result1?year=7%EA%B8%B0&menuId=MENU01649 .

12. ICRP; Eckerman K, Harrison J, Menzel HG, Clement CH. ICRP Publication 119: Compendium of dose coefficients based on ICRP Publication 60. Ann ICRP. 2012;41:Suppl 1. 1-130.
crossref pmid
13. Cho HG, Kim JE, Lee SN, Moon SK, Park YB, Yoon MH. Monitoring of artificial radionuclides in edible mushrooms in Korea. J Food Hyg Saf. 2018;33(6):488-494.
crossref
14. Lee SH, Oh JS, Lee KB, Lee JM, Hwang SH, Lee MK, et al. Evaluation of abundance of artificial radionuclides in food products in South Korea and sources. J Environ Radioact. 2018;184–185:46-52.
crossref pmid
15. Willett WC. Nutritional epidemiology. 2nd ed. New York, NY, Oxford University Press. 1998.

16. Kim S, Lee JS, Hong KH, Yeom HS, Nam YS, Kim JY, et al. Development and relative validity of semi-quantitative food frequency questionnaire for Korean adults. J Nutr Health. 2018;51(1):103-119.
crossref
17. Lee RD, Nieman DC. Nutritional assessment. 4th ed. Boston, MA, McGraw-Hill. 2007.

18. Changizi V, Jafarpour Z, Naseri M. Measurement of 226Ra, 228Ra, 137Cs and 40K in edible parts of two types of leafy vegetables cultivated in Tehran province-Iran and resultant annual ingestion radiation dose. Iran J Radiat Res. 2010;8(2):103-110.

19. Sugiyama H, Terada H, Takahashi M, Iijima I, Isomura K. Contents and daily intakes of gamma-ray emitting nuclides, 90Sr, and 238U using market-basket studies in Japan. J Health Sci. 2007;53(1):107-118.
crossref

APPENDICES

Appendix 1

Internal exposure self-questionnaire

Table 1
Radioactivity concentrations of 40K and 137Cs in foods (unit: Bq/kg-fresh)
Food 40K 137Cs
Persimmon 48.0±0.5 <30.7
Potato 133.2±1.3 <38.6
Egg 38.8±1.2 <22.3
Sweet potato 128.6±1.28 <39.5
Gastropods 56.6±0.63 <43.5
Mackerel 67.5±0.67 48.0±3.5
Chili 86.7±1.54 <108.3
Oyster 26.9±0.4 <38.5
Kimchi 85.0±16 -
Perilla leaf 133±16 -
Gracilaria sp. 419.5±4 <94.8
Hairtail 86.1±0.96 66.2±5
Green tea 465±125 185±84
Oyster mushroom 101.3 -
Kelp 1310.0 <32.0
Chicken 82.3±1.6 <28.3
Carrot 95.5±1.74 <186.1
Pig 73.3±1.3 <33.2
Tofu 43.0±0.52 <25.3
Rice cake 24.0±23 21.0±13
Ramen 60.0±13 -
Anchovy 41.6±0.6 <26.7
Radish 79.9±1.6 <170.4
Radish dried 107.7±1.9 <189.7
Seaweed 187.6±2 <74.5
Banana 141.0 -
Yellowtail 91.9±0.95 141.4±5.8
Pear 42.6±0.49 <17.9
Chinese cabbage 76.5±0.8 <29.7
Baekhab 39.6±0.5 <52.7
Bread 33.0±9 26.0
Apple 37.9±1.4 <15.9
Spanish mackerel 102.2±0.95 116.2±4.9
Lettuce 125.1±2.2 <200.6
Beef 66.7±1.2 <33.3
Conch 52.6±0.7 <49.0
Watermelon 39.6±0.4 <14.2
Gray mullet 70.0±0.78 64.1±4.8
Rice 24.4±0.3 <17.5
Mugwort 239.2±2.3 <85.2
Green pumpkin 70.8±1.42 <165.1
Agaricus bisporus 132.3 761.5
Onion 44.7±0.86 <16.8
Orange 25.6 -
Cucumber 56.8±0.98 <93.9
Squid 71.4 <24.0
Yogurt 42.0±19 15.0±7
Milk 45±3 <18.7
Horse mackerel 66.7±0.73 66.7±4.6
Gizzard 66.2±0.75 35.5±4.7
Coffee 1,077.0±216 781.0±274
Bean 528.9±2.1 <192.5
Pen shell 42.4±0.5 <27.3
Tomato 70.3±0.76 <23.3
Hijikia fusiforme 311.3±3.6 <83.6
Green onion 63.9±1.1 <105.3
Sea lettuce 285.3 -
Enoki mushroom 132.1±24 53.0±33
Grape 60.9±0.7 <22.4
Ark clams 40.7±0.47 <33.7
Skate 50.8±0.51 63.9±3.9
Mussel 29.5±0.35 <23.5
Total 8,478.1 4,968.8
Table 2
Annual effective dose from 40K and 137Cs due to food intake
Food Intake (kg/yr) Annual effective dose (μSv/yr)
40K 137Cs
Persimmon 4.909 1.460 0.00196
Potato 6.731 5.559 0.00337
Egg 10.373 2.492 0.00301
Sweet potato 4.676 3.728 0.00240
Gastropods 0.015 0.005 0.00001
Mackerel 1.110 0.464 0.00069
Chili 1.555 0.836 0.00219
Oyster 0.372 0.062 0.00019
Kimchi 23.528 12.399 -
Perilla leaf 0.920 0.758 -
Gracilaria sp. 0.004 0.009 -
Hairtail 0.515 0.275 0.00044
Green tea 3.570 10.291 0.00859
Oyster mushroom 0.445 0.280 -
Kelp 0.307 2.490 0.00013
Chicken 11.165 5.696 0.00410
Carrot 2.705 1.601 0.00654
Pig 17.670 8.035 0.00762
Tofu 6.866 1.830 0.00226
Rice cake 5.933 0.883 0.00162
Ramen 4.931 1.834 -
Anchovy 1.248 0.322 0.00043
Radish 9.348 4.629 0.02071
Radish dried 1.205 0.804 0.00297
Seaweed 0.296 0.344 0.00029
Banana 4.172 3.647 -
Yellowtail 0.073 0.042 0.00013
Pear 3.376 0.891 0.00079
Chinese cabbage 2.628 1.246 0.00101
Baekhab 0.022 0.005 0.00002
Bread 7.366 1.507 0.00249
Apple 17.648 4.142 0.00365
Spanish mackerel 0.153 0.097 0.00023
Lettuce 2.422 1.894 0.00637
Beef 8.161 3.377 0.00353
Conch 0.051 0.017 0.00003
Watermelon 4.712 1.156 0.00087
Gray mullet 0.044 0.019 0.00004
Rice 52.206 7.903 0.01187
Mugwort 0.055 0.081 0.00006
Green pumpkin 3.165 1.390 0.00679
Agaricus bisporus 0.175 0.144 0.00173
Onion 10.516 2.916 0.00230
Orange 2.300 0.365 -
Cucumber 5.460 1.921 0.00666
Squid 1.694 0.750 0.00053
Yogurt 5.413 1.410 0.00106
Milk 25.470 7.221 0.00620
Horse mackerel 0.007 0.003 0.00001
Gizzard 0.066 0.027 0.00003
Coffee 2.730 18.231 0.02772
Bean 0.982 3.219 0.00246
Pen shell 0.011 0.003 -
Tomato 5.256 2.291 0.00159
Hijikia fusiforme 0.029 0.056 0.00003
Green onion 3.946 1.563 0.00540
Sea lettuce 0.153 0.271 -
Enoki mushroom 0.310 0.254 0.00021
Grape 3.037 1.147 0.00088
Ark clams 0.102 0.026 0.00004
Skate 0.029 0.009 0.00002
Mussel 0.416 0.076 0.00013
Total 294.77 136.4 0.163
Editorial Office
319, HIT, 22-2, Majo-ro, Seongdong-gu, Seoul 133-791, Korea
Tel: +82-2-2297-9775   Fax: +82-2-2297-9776
Email: jrpr.gkim@gmail.com, jrpr.editorial@gmail.com
About |  Browse Articles |  Current Issue |  For Authors and Reviewers
Copyright © by Korean Association for Radiation Protection. Developed in M2PI