Trends in CT Examinations and Diagnostic Reference Level (DRL)

Medical exposure is increasing year by year. The main reason is an increase in CT examinations. X-ray examination has been shifting from conventional radiography to CT imaging. Although CT examinations account for only 7.9% of the total number of diagnostic medical examinations, the contribution is about 47% of the total collective effective dose due to diagnostic medical radiology in health-care level I countries according to the 1997-2007 survey by UNSCEAR. Dental X-ray examinations have hardly contributed it, but CT examination is indispensable in dentistry. Dentists also should follow the requirements for CT imaging by the ICRP recommendation and review CT imaging protocol based on national diagnostic reference level (DRL)

フクシマ ゲンシリョク ハツデンショ ノ ジコ カラ ミタ ホウシャセイ ドウイ ゲンソ ト ホウシャセン

The words“ radiation and radioactivity” have been become famous after the Fukushima Daiichi nuclear disaster. Alfa, beta, gamma and neutron rays irradiated from radioisotopes are well known to the world. Alfa and beta rays have weak penetration. Alfa and beta rays are stopped by a sheet of paper and a thin aluminum plate, respectively. And those are taken into account at internal exposure because all energy from those rays is absorbed in the surrounding tissues. If DNA strand in the cell is broken by the energy absorbed, some radiation hazard may occur. The units of radiation became also famous. Becquerel (Bq), Sievert (Sv) and Sv/h are addressed under a leaflet for the pubic by public office and citizen has been to monitor the radiation dose contained in food and water. In the early stage 131-I (iodine) having about 8 days half-life period was emitted into the air and many people were exposed. Recently the 131-I at that time was decayed but two types of radioactive cesium 134-Cs and 137-Cs remained. Because 134-Cs and 137-Cs have about 2 years and 30 years halflife period respectively and emit beta and gamma ray, no radiation effect will require hundred years. Therefore I hope that many people will acquire the greater knowledge of radiation

History of Digital Detectors in Intraoral Radiography

The first digital sensor used in intraoral radiography, RadioVisioGraphy was introduced in 1987. It was based on the activity of a charged-Coupled Device (CCD) sensor. Later on, other digital sensors became commercially available, including the Digora featuring an imaging plate coated with photostimulable phosphor (PSP) in 1994 and the complementary metal-oxide semiconductor-based sensor, CDR active pixel sensor, in 1998. These technologies have recently undergone considerable improvement, and several dental clinics have switched from film-based systems to digital imaging. In the early days, digital sensors were considered inferior to film in clinical diagnostics, but according to recent research results, there is no longer any significant difference because of the improvement in performance. However, our latest research using a new evaluation method and a precise phantom model indicated some differences between the performance of CCD and PSP systems and further differences between PSP systems of different function and performance

Influence of Radiation Education on Risk Perception in Japanese Dental Students

Since the Fukushima Dai-ichi Nuclear Power Plant accident in 2011, the Japanese Government has been focusing radiation education in elementary, middle and high schools to improve public understanding about the continuing existence of nuclear plants. The government developed two supplementary texts about radiation, including nuclear power, for elementary school, middle school, and high school students. The authors evaluated the content of these texts by questionnaire research and found them very difficult to understand even for dental students. After that we examined the relationship between radiation education and risk perception. The results of the present study indicate that radiation education might change students’ risk perception with regard to radiation

Current status and history of radiation education : considering the Fukushima Dai-ichi nuclear disaster

福島原発の事故前後で国民の放射線に対する関心が大きく変化した．また大部分の原発は再稼働の目安が立たず，電力政策の変更を余儀なくされた．最終的には国民の判断に委ねられるが，放射線教育は30 年にわたり初等教育で行われなかったため，多くの人々は知識が不十分な状態にある．政府はこの問題解決の一つとして，初等・中等教育用の放射線副読本を作成した．しかし専門家からみて，むずかしい語句が多く問題を感じた．将来X 線を日常的に扱う歯学部学生を対象とし，副読本の理解度を調べた結果，十分に理解できていないことが判明し，初等・中等教育における放射線教育の方法を再考する必要があると結論づけられた．また多くの報告から放射線教育者の育成が早急に望まれることも判明した．本総説の目的は，放射線教育の歴史を振り返り，現在の国民の放射線に対する知識の現状，そして福島原子力発電所の事故と放射線との関係を知ってもらうことである．Since the Fukushima Dai-ichi nuclear disaster in 2011, Japanese people’s interest in radiation has dramatically changed．After the incident, most nuclear power plants were switched off and they have not yet resumed operation．This has forced the Japanese government to alter the electric energy policy．Although the energy policy is dependent on public opinion, the general public has little knowledge of radiation and atomic power, because radiation education has not been taught in elementary or secondary schools for approximately 30 years．Hence, the government has created two supplementary texts on radiation—one for elementary school students, and the other for middle and high school students．As radiation experts, however, we felt that many phrases used in the texts were too difficult, and therefore, we launched a survey to gauge dental students’ understanding of the texts, as dental students will routinely use X-rays as part of their work．The survey revealed that the dental students did not fully understand the phrases in the supplementary text for elementary school students．Thus, the method of radiation education needs to be rethought．Furthermore, reports on the radiation knowledge questionnaire helped us realize that radiation knowledge is scarce among high school and university students．There were previously very few teachers who could teach about radiation in junior-high and high schools, and this skill is highly desired．The purpose of the review is to reconsider the history of Japanese radiation education in elementary and secondary schools, to update the current status of public knowledge of radiation, and to explain the status of radioisotopes in the Fukushima Dai-ichi nuclear disaster

Knowledge and risk perception of radiation for Japanese nursing students after the Fukushima Nuclear Power Plant disaster

Background: The Japanese have had three experiences of radiation disasters: the atomic bombs dropped on Hiroshima and Nagasaki in 1945, and the 2011 Fukushima Nuclear Power Plant disaster. The former two experiences have been covered in compulsory education programs. In light of these incidents, a strong fear of radiation has pervaded people of several generations. In such a situation, the role of nurses is important. When nurses treat residents, their attitudes change depending on how they understand and feel about radiation. The foundations of these attitudes are formed through student education. Hence, it is necessary to explore nursing students' understanding and risk perception of radiation, and the nature of radiation education received. Objectives: To assess the levels of understanding and risk perception of nursing students regarding radiation. Design: Cross-sectional survey. Methods: A questionnaire survey was administered to all students (74 first-year, 79 second-year, 65 third-year, and 69 fourth-year students) in the nursing department of a Japanese national university. The response rate was 84%. Respondents were asked to rate their level of understanding of 50 phrases chosen from two supplementary texts about radiation for elementary school students and for middle and high school students, prepared by the Japanese Ministry. Further, they were asked to rate their risk perception for 30 events, and to answer six questions about radiation. Results: It was found that knowledge about radiation among Japanese nursing students was poor, because sufficient radiation education had not been provided. Hence, they displayed a greater fear of X-rays as compared to American students and members of the League of Woman Voters. However, it was also found that an increase in understanding might decrease risk perception. Conclusions: It was concluded that nursing students require adequate education about radiation, in order to reduce their fear of X-rays and to mitigate their risk perception

Comparison of radiation risk perception and knowledge of radiation between Indonesian and Japanese dental students

The purpose of the study was to obtain basic data to identify problems in radiation education in a situation where confidence in nuclear power has fluctuated over time and fear of nuclear power has increased globally due to nuclear power plant disasters at Chernobyl and Fukushima. We conducted a questionnaire survey on understanding and risk perception of radiation and atomic power, before and after lectures, for 107 Japanese and 137 Indonesian dental students. Thirty-six phrases were extracted from two supplementary texts about radiation created by the Japanese Ministry of Education, Culture, Sports, Science and Technology, and 30 events commonly used in research on risk perception were used. The students were asked to rate their level of understanding of 36 phrases and risk perception of 30 events. Moreover, the students were asked to answer 6 general questions about radiation. For Japanese students, understanding of radiation increased and risk perception for both nuclear power and X-rays decreased after lectures (p<0.05). Concerning nuclear power, the risk-value declined as the level of understanding increased (p<0.01). However, for Indonesian students, who had lectures on only radiation excluding nuclear power in dental radiology, risk perception increased for X-ray after lectures (p<0.05). This indicates that thought and custom, in the absence of knowledge, are influenced by lectures. In general, it is said that increase in knowledge will lower risk perception, but even if radiation education is imparted, risk perception may rise if the lectures are not understood properly. It was concluded that educators need to incorporate sufficient knowledge in their teachings, and correct thinking, to mitigate the risk of future radiation education giving the opposite of the intended effect

Dental students’ levels of understanding panoramic

Background/purpose: In dentistry, panoramic radiography is an important examination technique. The Faculty of Dentistry at Tokushima University educates students about panoramic radiographic anatomical landmarks. The purpose of this study was to investigate differences in the understanding of each panoramic anatomical landmark among students. Materials and methods: This study analyzed the results of 40 fifth- and 79 sixth-year faculty students who had taken a written examination to clarify their knowledge of anatomical landmarks in 28 panoramic radiographic regions. Anatomical landmarks were classified into 3 categories: , , and to compare correct answer rates. Results: The mean overall correct answer rate by the 119 students for the 28 regions was 53%. The rate did not vary between the 2 academic years. On comparison of the 3 categories, significant differences were only observed between and , as the values for the latter were lower. Among the anatomical landmarks, the rates for the condylar head, hyoid bone, panoramic innominate line, styloid process, and nasopalatine line were higher, and those for ghost images of the contralateral nasopalatine line, the cervical vertebrae, mandibular foramen, mastoid air cell, and posterior pharyngeal wall were lower. The values for , such as the dorsum of tongue, middle and inferior nasal conche, and middle and inferior nasal meatuses, were also lower. Conclusion: These results indicate the necessity of improving educational approaches for regions with lower rates of correct answers