Basics of particle therapy II: relative biological effectiveness

In the previous review, the physical aspect of heavy particles, with a focus on the carbon beam was introduced. Particle beam therapy has many potential advantages for cancer treatment without increasing severe side effects in normal tissue, these kinds of radiation have different biologic characteristics and have advantages over using conventional photon beam radiation during treatment. The relative biological effectiveness (RBE) is used for many biological, clinical endpoints among different radiation types and is the only convenient way to transfer the clinical experience in radiotherapy with photons to another type of radiation therapy. However, the RBE varies dependent on the energy of the beam, the fractionation, cell types, oxygenation status, and the biological endpoint studied. Thus this review describes the concerns about RBE related to particle beam to increase interests of the Korean radiation oncologists' society.

Basics of particle therapy I: physics

With the advance of modern radiation therapy technique, radiation dose conformation and dose distribution have improved dramatically. However, the progress does not completely fulfill the goal of cancer treatment such as improved local control or survival. The discordances with the clinical results are from the biophysical nature of photon, which is the main source of radiation therapy in current field, with the lower linear energy transfer to the target. As part of a natural progression, there recently has been a resurgence of interest in particle therapy, specifically using heavy charged particles, because these kinds of radiations serve theoretical advantages in both biological and physical aspects. The Korean government is to set up a heavy charged particle facility in Korea Institute of Radiological & Medical Sciences. This review introduces some of the elementary physics of the various particles for the sake of Korean radiation oncologists' interest.

Co-authorship patterns and networks of Korean radiation oncologists

PURPOSE: This research aimed to analyze the patterns of co-authorship network among the Korean radiation oncologists and to identify attributing factors for the formation of networks. MATERIALS AND METHODS: A total of 1,447 articles including contents of 'Radiation Oncology' and 'Therapeutic Radiology' were searched from the KoreaMed database. The co-authorship was assorted by the author's full name, affiliation and specialties. UCINET 6.0 was used to figure out the author's network centrality and the cluster analysis, and KeyPlayer 1.44 program was used to get a result of key player index. Sociogram was analyzed with the Netdraw 2.090. The statistical comparison was performed by a t-test and ANOVA using SPSS 16.0 with p-value < 0.05 as the significant value. RESULTS: The number of articles written by a radiation oncologist as the first author was 1,025 out of 1,447. The pattern of co-authorship was classified into five groups. For articles of which the first author was a radiation oncologist, the number of single-author articles (type-A) was 81; single-institution articles (type-B) was 687; and multiple-author articles (type-C) was 257. For the articles which radiation oncologists participated in as a co-author, the number of single-institution articles (type-D) was 280 while multiple-institution articles (type-E) were 142. There were 8,895 authors from 1,366 co-authored articles, thus the average number of authors per article was 6.51. It was 5.73 for type-B, 6.44 for type-C, 7.90 for type-D, and 7.67 for type-E (p = 0.000) in the average number of authors per article. The number of authors for articles from the hospitals published more than 100 articles was 7.23 while form others was 5.94 (p = 0.005). Its number was 5.94 and 7.16 for the articles published before and after 2001 (p = 0.000). The articles written by a radiation oncologist as the first author had 5.92 authors while others for 7.82 (p = 0.025). Its number was 5.57 and 7.71 for the Journal of the Korean Society for Therapeutic Radiology and Oncology and others (p = 0.000), respectively. Among the analysis, a significant difference in the average number of author per article was indicated. The out-degree centrality of network among authors was 4.26% (2.03.7.09%) while in-degree centrality was 1.31% (0.53.2.84%). The three significant nodes were classified and listed as following: Choi, Eun Kyung for 1991-1995, Kim, Dae Young for 1998-2001, Park, Won and Lee, Sang Wook for 2003-2010. Choi, Eun Kyung and Kim, Dae Young appeared in two cases, and ranked as the highest degree in centrality. In the key player analysis, Choi, Eun Kyung and Lee, Sang Wook appeared in two cases, and ranked as the highest. From the cluster analysis, Sungkyunkwan University, Seoul National University and Yonsei University revealed as the three large clusters when Ulsan University, Chonnam National University, and Korea Institute of Radiological & Medical Science as the medium clusters. CONCLUSION: The Korean radiation oncologist's society shows a closed network with numerous relationships among the particular clusters, and the result indicates it is different from other institutions in the pattern of co-authorship formation of the major hospitals.

The Analysis of Co-authorship and Networks among the Korean Pathologists

BACKGROUND: To evaluate the characteristics of the co-authorship and its network within the Korean Pathologists' Society. METHODS: In the KoreaMed database, 11,420 articles and 72,478 authors from 1991 to 2010 were searched. The patterns of co-authorship of the authors and institutions were analyzed to build a network matrix. The network centrality indices were measured with UCINET 6.0 and sociogram, and were drawn with Netdraw 5.0. KeyPlayer 1.44 was used for key player analysis. RESULTS: The number of articles that pathologist participated in increased; however, the number of articles that the pathologists are the first author did not increase. The centrality degrees from 1991 to 2010 were 4.16% and 0.3% for the institutions and authors network, respectively. From 1991 to 2000, Seoul National University had the highest degree of centrality and was a key player. However, from 2001 to 2010, Ulsan replaced the position. For the authors, Chi, Je Geun was highest centrality author and key player during the 1991 to 2000 time period. From 2001 to 2010, Yoo, Jinyoung had the highest degree of centrality and Kim, Na Rae was a key player. Overall, most of the centrality indices were occupied by only a few institutions and authors. CONCLUSIONS: The network among the pathologist society is a typical small world society.

A Long Term Results of External Beam Radiation Therapy in Hemophilic Arthropathy of the Ankle in Children

Bleeding into joint space is critical to develop hemophilic arthropathy. To reduce the frequency of bleeding in the ankle joint of children with hemophilic arthropathy, low dose external beam irradiation was performed for 37 patients. Among them, 35 patients followed-up for longer than 1 yr (median 87 months) were enrolled for analysis. The average number of bleedings per month was 3.6 during one year prior to radiation therapy. After radiation therapy, it was decreased to 2.1 during the first year, after then it was maintained in the range of 1.0 to 1.5 until the tenth year. The bleeding frequency was reduced to 42% at the first year and it was maintained in the range of 58% to 73% from the second to the tenth year. Especially the patients who had 3 or more bleedings per month, and who had MRI score more than 3 showed significant decreases. During the follow-up period, growth disturbances and secondary malignancies were not found. External beam radiotherapy can be considered for the hemophilic patients with surgical or isotope therapies are not amenable.

The Characteristics of a Research Network for Radiation Oncology in Korea / 대한방사선종양학회지

PURPOSE: To evaluate the structural characteristics of a scientific network of radiation oncology society. MATERIALS AND METHODS: A total of 1,512 articles published from 1986 to April 2010 with the terms 'radiation oncology' or 'therapeutic radiology' were obtained in the KoreaMed database. The co-authors were analyzed according to their affiliation, and their relationship was used to build a matrix. With the matrix, centralization indices and the Key Player index were analyzed. We used UCINET 6.0 for the network analysis, Netdraw for determining a sociogram and Key Player 1.44 for the key player analysis. RESULTS: The centralization of the radiation oncology field decreased from 8.29% for the period from 1986~1990 to 1.84% from 2006~2010. However, when the Korean Journal of Medical Physics was excluded, centralization increased from 2.32% for the period from 2001~2005 to 3.80% from 2006~2010. This suggested that the communication in the clinical research field of radiation oncology is decreasing. In a node centralization analysis, Seoul National University was found to be the highest at 7.9%. Seoul National University showed the highest indices in the Outdegree (6.50%) and Indegree (8.54%), in addition to Betweenness (14.94%) and Eigenvector (135.234%). The Key Player analysis indicated that Inha University had the highest index at 0.491, but when the Korean Journal of Medical Physics was excluded, Yonsei University had the highest Key Player index at 0.584. CONCLUSION: The degree centrality in the network of radiation oncology decreased in the most recent period as more institutions are participating in network. However, the Betweenness centrality is still increasing, suggesting that the communications among research groups (clique) in radiation oncology is warranted.

Analysis of Scientific Publication Networks among Medical Schools in Korea / 대한의료정보학회지

OBJECTIVES: This research was intended to analyze the special characteristics and structure of social networks among Korean medical schools for the purpose of providing knowledge regarding medical field structure, dynamics, and potential paradigm development. METHODS: A collaborative 12-year data set of 35,469 published articles in the SCOPUS(R) database was analyzed. Among ISI subcategories, 61 having more than 20 articles were scrutinized. Following identification of correspondence and co-authorship, centralization indices and Key Player analysis were run for each subcategory. Medical schools were grouped into uniform clusters with convergence of iterated correlation (CONCOR) for structural equivalence. Finally, multidimensional scaling was used to visualize similarities. RESULTS: All centralization indexes analyzed demonstrated a shift in the degree of centralization in the network of medical schools throughout the period examined. Betweenness centrality and eigenvector centrality in particular revealed a dramatic change indicating minimization of the role of a specific "gatekeeper". Key Player analysis confirmed Seoul National University as a constant 'key player' throughout the period evaluated and for the subcategories examined as well. CONCLUSIONS: This study provided insight into the scientific network among the medical schools of Korea. By understanding this network, a strategy to strengthen the basis of research may be developed.

Current Status of Scientific Citation Index Expanded Article Publications and Relationship with the Human Resources of Medical Schools in Korea / 대한의료정보학회지

OBJECTIVE: The purpose of this paper was to quantify both the output and the impact of the relationship between Korean medical schools and their human resource departments and their ability to support the basic data for research goals of Korean medical schools. METHODS: The SCOPUS database was used to identify SCIE (scientific citation index expanded) articles produced by Korean medical schools between 1997 to 2008. The SCIE criteria, impact factors, and citation numbers were classified according to the database of Thomson Scientific Company. The human resources of medical schools were collected, such as the number of professors, graduate students, clinical fellows, residents, interns, and research assistants, through use of the medical deans' association biannual report. RESULTS: There was a significant difference across Korean medical schools in the number of the SCIE articles and citation numbers, resulting in only a few institutions producing most of the impact. Among the variables, the proportion of professors of basic medical science (p<.01) and the number of research faculties per professor (p<.01), were related significantly to the SCIE per professor. The only factor affecting both SCIE number and SCIE per professor was the number of research faculties per professor. The number of graduate students in the medical school had no impact on productivity. CONCLUSION: For the medical schools with restricted resources, the strategic plans for proper management of human resources are needed to promote scientific publication.

A Retrospective Study of the Radiotherapy Care Patterns for Patients with Laryngeal Cancer and Comparison of Different Korean Hospitals Treated from 1998 through 1999 / 대한방사선종양학회지

PURPOSE: To investigate the care patterns for radiation therapy and to determine inter-hospital differences for patients with laryngeal carcinoma in Korea. MATERIALS AND METHODS: A total of 237 cases of laryngeal carcinoma (glottis, 144; supraglottis, 93) assembled from 23 hospitals, who underwent irradiation in the year of 1998 and 1999, were retrospectively analyzed to investigate inter-hospital differences with respect to radiotherapy treatment. We grouped the 23 hospitals based on the number of new patients annually irradiated in 1998; and designated them as group A (> or =900 patients), group B (> or =400 patients and <900 patients), and group C (<400 patients). RESULTS: The median age of the 237 patients was 62 years (range, 25 to 88 years), of which 216 were male and 21 were female. The clinical stages were distributed as follows: for glottis cancer, I; 61.8%, II; 21.5%, III; 4.2%, IVa; 11.1%, IVb; 1.4%, and in supraglottic cancer, I; 4.3%, II; 19.4%, III; 28.0%, IVa; 43.0%, IVb; 5.4%, respectively. Some differences were observed among the 3 groups with respect to the dose calculation method, radiation energy, field arrangement, and use of an immobilization device. No significant difference among 3 hospital groups was observed with respect to treatment modality, irradiation volume, and median total dose delivered to the primary site. CONCLUSION: This study revealed that radiotherapy process and patterns of care are relatively uniform in laryngeal cancer patients in Korean hospitals, and we hope this nationwide data can be used as a basis for the standardization of radiotherapy for the treatment of laryngeal cancer.

Different Expressions of HIF-1alpha, Bcl-2 and Baxin DU145 Prostate Cancer Cells Transplanted in Nude Mouse between X-Ray and Neutron Irradiation / 대한방사선종양학회지

PURPOSE: To investigate the radiobiologic effects of neutron and X-ray irradiation on DU-145 prostate carcinoma cells by identifying the differences of HIF-1alpha expression and apoptosis. MATERIALS AND METHODS: Nude mice were injected with the human prostate cancer cell line, DU-145, and then irradiated with 2 Gy and 10 Gy X-rays, or 0.6 Gy and 3.3 Gy neutrons, respectively. The mice were sacrificed at 24 hours and 120 hours after irradiation. The expression levels of HIF-1alpha, Bcl-2 and Bax were compared with immunohistochemical staining and western blotting. The apoptotic indexes were compared with the Terminal deoxynucleotidyl biotin-dUTP nick and labeling (TUNEL) assay. RESULTS: At day 1, HIF-1alpha and Bcl-2 expression decreased, while Bax expression and the number of TUNEL positive cells increased in neutron irradiated groups for the control and X-ray irradiated groups. The Bcl-2/Bax ratio was significantly lower in the neutron irradiated groups regardless of dose (p=0.001). The same pattern of the differences in the expressions of the HIF-1alpha, Bcl-2, Bax, Bcl-2/Bax ratio, and apoptotic indexes were indentified at day 5. HIF-1alpha expression was related with Bcl-2 (p=0.031), Bax (p=0.037) expressions and the apoptotic indexes (p=0.016) at day 5. CONCLUSION: Neutron irradiation showed a decrease in HIF-1alpha, Bcl-2 expression, and Bcl-2/Bax ratio, but increased Bax expression regardless of dose. This study suggests that the differences radiobiological responses between photon and neutron irradiation may be related to different HIF-1alpha expression and subsequent apoptotic protein expressions.

Prediction of Hospital Charges for the Cancer Patients with Data Mining Techniques / 대한의료정보학회지

OBJECTIVE: Predictions of hospital charges for cancer patients are very important, because they provide a basis for allocating medical resources in the hospital and for establishing national medical policies. But previous studies to predict hospital charges were mainly based on statistical analysis, which has used only a small aspect among huge medical data so that the prediction power was limited. Thus we developed four data mining models, including two artificial neural network (ANN) models and two classification and regression tree (CART) models, to predict both the total amount of hospital charges and the amount paid by the insurance of cancer patients and compared their efficacies. METHODS:The data was generated from400,625 medical records of 1,605 cancer patients who had been hospitalized toKyungHeeUniversityHospital fromMarch 1, 2003 to February 29, 2004. Clementine 8.1 programwas used to build four data mining prediction models, two for the total amount and two for the amount paid by insurance. The variables included all of the data fields of standard medical record form of Korea. The neural network model used feed-forward back propagation method, which had 2 hidden layers. For decision tree model, RELIEFF method was used and the maximum tree depth was set to 30.We divided the dataset into 67%of training dataset and 33%of test dataset, using stratified sampling. Linear correlation coefficient and gain chart were compared. RESULTS: The ANN models showed better linear correlation coefficient than the CART models in predicting both the total amount (0.824 vs. 0.791) and the amount paid by insurance (0.838 vs. 0.699). The estimated accuracy of ANN model was more than 98%to predict both total amount and amount paid by insurance. The CART model for total amount showed that the relative importance of the variables were duration of admission(0.073), number of consultation(0.061), and treatment group 16(0.06). The CART model for the amount paid by insurance showed that the relative importance of the cariables were duration of admission (0.09), number of ICUadmission (0.063), and number of consultations (0.062). The percent gain of ANN model shows better %gain than CART to predict total amount but to predict amount paid by insurance, ANN showed similar pattern to CART CONCLUSION: The ANNmodels showed better prediction accuracy than CART models. However, the CART models, which serve different information from ANN model, can be used to allocate limited medical resources effectively and efficiently. For the purpose of establishing medical policies and strategies, using those models together is warranted.

Statistical Errors in Papers Published in the Journal of the Korean Society for Therapeutic Radiology and Oncology / 대한방사선종양학회지

PURPOSE: To improve the quality of the statistical analysis of papers published in the Journal of the Korean Society for Therapeutic Radiology and Oncology (JKOSTRO) by evaluating commonly encountered errors. MATERIALS AND METHODS: Papers published in the JKOSTRO from January 2006 to December 2007 were reviewed for methodological and statistical validity using a modified version of Ahn's checklist. A statistician reviewed individual papers and evaluated the list items in the checklist for each paper. To avoid the potential assessment error by the statistician who lacks expertise in the field of radiation oncology; the editorial board of the JKOSTRO reviewed each checklist for individual articles. A frequency analysis of the list items was performed using SAS (version 9.0, SAS Institute, NC, USA) software. RESULTS: A total of 73 papers including 5 case reports and 68 original articles were reviewed. Inferential statistics was used in 46 papers. The most commonly adopted statistical methodology was a survival analysis (58.7%). Only 19% of papers were free of statistical errors. Errors of omission were encountered in 34 (50.0%) papers. Errors of commission were encountered in 35 (51.5%) papers. Twenty-one papers (30.9%) had both errors of omission and commission. CONCLUSION: A variety of statistical errors were encountered in papers published in the JKOSTRO. The current study suggests that a more thorough review of the statistical analysis is needed for manuscripts submitted in the JKOSTRO.

Current Status of SCI & SCIE Publications in the Field of Radiation Oncology in Korea / 대한방사선종양학회지

PURPOSE: To investigate current status of SCI (Science Citation Index) and SCI Expanded publications of Korean radiation oncologists. MATERIALS AND METHODS: Published SCI and SCIE articles the conditions of first author's address as "Korea" and "Radiation Oncology" or "Therapeutic Radiology" were searched from Pubmed database. RESULTS: From 1990 to 2006, 146 SCI articles and 32 SCIE articles were published. Most frequently published journal was International Journal of Radiation Oncology Biology Physics, where 56 articles were found. Articles with 30 or more citations were only five and 10 or more citations were 26. Yonsei University, which had 57 published articles, was the top among 19 affiliations which had one or more SCI and SCIE articles. Authors with five or more articles were 9 and Seong J. of Yonsei University was the top with 19 articles. CONCLUSION: The investigations showed disappointing results. The members of Korean Society of Radiation Oncologists must consider a strategy to increase SCI and SCIE publications.

Erratum / 대한방사선종양학회지

No abstract available.

Comparison of Career Choice Motivation and Moral Reasoning Ability between Students in Baccalaureate and Graduate-entry Programs / 한국의학교육

PURPOSE: This study was performed to investigate the differences in career choice motives and moral reasoning ability between students in baccalaureate and graduate-entry medical programs. METHODS: Forty-five students from a baccalaureate program and thirty-eight students from a graduate-entry program participated in this study. The students were required to fill out both the Career Choice Motivation Inventory and Defining Issues Test(DIT). The Career Choice Motivation Inventory is a 20-item questionnaire, which investigates five dimensions: effect of others, job security, interest in science, service and working with people, and working condition. Independent t-test was performed to compare the two groups. Pearson correlation coefficients were calculated to investigate the relationship among variables. RESULTS: There were significant differences in career choice motivations between the two groups. Students in the graduate-entry program were more likely to be motivated by scientific interest and opportunities to care for people. Status and job security were stronger factors in the baccalaureate students. For the students in this program, there were positive associations among their motives- interest in medical science, serving people, and working condition. There was no significant difference in moral reasoning ability between the two groups. CONCLUSION: Students in the graduate-entry medical program seem to have more professional and altruistic motivations for entering medicine. Although there is nostatistical significance, graduate students have numerically higher moral reasoning abilities compared to their counterparts. These results validate that a graduate-entry program provides an important alternative for student selection.

Adaptive Responses Induced by Low Dose Radiation in Dentate Gyrus of Rats

The purpose of this study is to investigate the mechanism of alternative responses to low dose irradiation for neuronal cell proliferation in the dentate gyrus of rats. To determine the effect of a single exposure to radiation, rats were irradiated with a single dose of 0.1, 1, 10 or 20 Gy. To determine the effect of the cumulative dose, the animals were irradiated daily with 0.01 Gy or 0.1 Gy from 1 to 4 days. The neuronal cell proliferation was evaluated using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. Four consecutive daily irradiations with a 0.01 Gy/fraction increased the number of BrdU-positive and Ki-67-positive cells in a dose dependent manner, but this did not affect the number of TUNEL-positive cells. However, there was not a dose dependent relationship for the 0.1 Gy/fraction irradiation with the number of BrdU, Ki-67 and TUNEL positive cells. Our data support the explanation that the adaptive response, induced by low-dose radiation, in the hippocampus of rats is more likely a reflection of the perturbations of cell cycle progression.

Low Dose Radiation Overcomes Diabetes-induced Suppression of Hippocampal Neuronal Cell Proliferation in Rats

We investigated the effect of low dose radiation on diabetes induced suppression of neurogenesis in the hippocampal dentate gyrus of rat. After 0.01 Gy, 0.1 Gy, 1 Gy and 10 Gy radiation was delivered, the dentate gyrus of hippocampus of streptozotocin (STZ)-induced diabetic rats were evaluated using immunohistochemistry for 5-bromo-2-deoxyuridine (BrdU), caspase-3, and terminal deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL) staining. The number of BrdU positive cells in the non-diabetic rats, diabetic rats without radiation, diabetic rats with 0.01 Gy radiation, diabetic rats with 0.1 Gy radiation, diabetic rats with 1 Gy radiation and diabetic rats with 10 Gy radiation were 55.4+/-8.5/mm2, 33.3+/-6.4/mm2, 67.7+/-10.5/mm2, 66.6+/-10.0/mm2, 23.5+/-6.3/mm2 and 14.3+/-7.2/mm2, respectively. The number of caspase-3 positive cells was 132.6+/-37.4/mm2, 378.6+/-99.1/mm2, 15.0+/-2.8/mm2, 57.1+/-16.9/mm2, 191.8+/-44.8/mm2 and 450.4+/-58.3/mm2, respectively. The number of TUNEL-positive cells was 24.5+/-2.0/mm2, 21.7+/-4.0/mm2, 20.4+/-2.0/mm2, 18.96+/-2.1/mm2, 58.3+/-7.9/mm2, and 106.0+/-9.8/mm2, respectively. These results suggest low doses of radiation paradoxically improved diabetes induced neuronal cell suppression in the hippocampal dentate gyrus of rat.

Number of Radiation Oncologists in Korea, Adequate or Surplus? / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The purpose of this research is to discern and address the issues related to the radiation oncology manpower supply and its distribution. MATERIALS AND METHODS: The statistical data of the Annual Report of the Korea Central Cancer Registry (KCCR) from 1997 to 2002 and the Annual Report of the Korean Society of Radiation Oncology (KOSTRO) from 1997 to 2004 were used to predict the status of the human resources in 2015. The estimated demand and supply were calculated with the Microsoft Excel(R) program (Microsoft, Redmond, WA). RESULTS: The demand for radiation oncologists is estimated to be 161 in 2015 and about 4.9 radiation oncologists will be in demand annually. In contrast, an average of 15 new radiation oncologists will be supplied annually so that the accumulated surplus of radiation oncologists until 2015 is estimated to be 74.1. The main reason for the surplus comes from the discrepancy between the increased number of radiation therapy patients and the need for radiation oncologists. When there is an increase of 1,000 radiation therapy patients, the demand for radiation oncologists increases only by 2.4. This phenomenon is especially evident in the top 10 hospitals where the average number of radiation therapy patients per radiation oncologist is 341, which is 58% higher than the average number (215) of other 46 hospitals. CONCLUSION: To prevent a surplus and to maintain the quality of management, the number of radiation therapy patients per radiation oncologist should be limited. Furthermore, coordinate control of the number of residency positions should be seriously considered.

Development of Web-based Dosimetry Calibration Program for High Energy Radiation / 의학물리

Absorbed dose dosimetry protocols of high energy photon and electron beams, which are widely used and based on an air kerma calibration factors, have somewhat complex formalism and limitations for improving dosimetric accuracy due to uncertainty of the physical parameters used. Recently the IAEA and the AAPM published the absorbed dose to water-based dosimetry protocol. In this work web-based dose calibration program for IAEA TRS-398 and AAPM TG-51 protocols were developed. This program developed using the Visual C# language can be used in the internet. User selectable dosimetry protocol on the web allows the absorbed dose to water data of the two protocols at a reference point to be easily compared, and enables to conveniently manage and understand the current status of the dosimetry calibration performed at participating institutions in korea. This program and the resultant database from the web-based calibration can be useful in developing new dosimetry protocols in Korea.

The Effect of Low Dose Radiation on the Neuronal Cell Proliferation in Diabetic Rats / 대한방사선종양학회지

PURPOSE: To investigate the effect of low dose radiation on neuronal cell proliferation in diabetic rats. MATERIALS AND METHODS: A group of rats (first group) were divided into three subgroups (nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy groups) to determine the effect of radiation on normal hippocampal neuronal cell proliferation. A further group of rats (second group) were divided into six subgroups (nondiabetic control, diabetic control, diabetic 0.01 Gy, diabetic 0.1 Gy, diabetic 1 Gy and diabetic 10 Gy groups) to determine the effect of radiation on hippocampal neuronal cell proliferation under diabetic conditions. Using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), the number of neuronal cells in the dentate gyrus of all the groups was counted. RESULTS: The number of BrdU-positive cells in the dentate Gyrus of the nondiabetic control, nondiabetic 0.1 Gy and nondiabetic 10 Gy subgroups of the first group were 45.96+/-3.42, 59.34+/-5.20 and 19.26+/-2.98/mm2, respectively. The number of BrdU-positive cells in the dentate gyrus of the diabetic control, diabetic 0.01 Gy, diabetic 0.1 Gy, diabetic 1 Gy and diabetic 10 Gy subgroups of the second group were 55.44+/-8.57, 33.33+/-6.46, 67.75+/-10.54, 66.63+/-10.05, 23.59+/-6.37 and 14.34+/-7.22/mm2, respectively. CONCLUSION: Low dose radiation enhances cell proliferation in the dentate gyrus of STZ-induced diabetic rats.