Due to the unique nature of nuclear energy and radiation, nuclear disasters have radiation-based biological and psychological effects on both the immediate and over time effects. The radiation
effects on human beings can be deterministic, stochastic, and psychological. It is necessary to establish a strategy that can reasonably reduce these effects in nuclear and radiological
emergencies. For effective response, it is important to establish a phased resource utilization plans for radiation emergency medicine at national level. In this study, the definition of emergency
preparedness categories according to the international atomic energy agency publication was used to classify and analyze past nuclear and radiological emergencies. So we assumed scenarios using our classification and analysis results. And also radiation emergency medicine strategies should be arranged based on the roles of medical response institute during nuclear and radiological emergencies occured.

Computed tomographic angiography (CTA) is a widely used noninvasive imaging technique for visualizing and evaluating vascular diseases. For global anatomical evaluation of vascular diseases,
CTA is superior to conventional catheter angiography because of its unlimited angulation in image projection. However, arterial calcification and/or vascular implants such as metallic stents could
hinder the evaluation of lesions inside. Additionally, the spatial resolution of CT is not small enough to evaluate peripheral vascular structures. Recent technical developments in CT allowed several new image processing techniques. The areas of technical developments are image subtraction and/or energy subtraction, which are used to detect fine luminal images. Another area of technical development is ultra-high-resolution CT, which has four times finer in-plane spatial resolution than conventional CT. There are other developments in image quality improvement and/or radiation dose reduction. Thus, new techniques and environments of CT allow finer vascular and structural imaging without invasiveness. In this review, the details of these techniques are described, and future insights are discussed.

The public is constantly exposed to radiation from a variety of sources, both natural and artificial. Natural sources of radiation include cosmic radiation; external radiation from radioactivity in the
earth’s crust; the radioactive gases radon and thoron released from radioactivity in the earth’s crust; and radioactivity transferred to foodstuffs. There are also sources of artificial radioactivity in
the environment. The testing of nuclear weapons, nuclear accidents and authorised releases from nuclear facilities abroad have all resulted in radioactivity reaching Ireland. Radioactivity is also
released in small amounts into the Irish marine environment from hospitals and research facilities located along the Irish coastline. As with sources of natural radioactivity, artificial radioactivity
can give an external radiation exposure and also be transferred through the food chain to give an internal radiation exposure.
This work outlines the methodologies used to evaluate the dose received to members of the Irish public from the exposure pathways outlined above. The average annual effective dose to a
person in Ireland from all sources of radiation is now estimated as 4037 μSv. Natural sources of radioactivity account for 86% of the total effective dose in Ireland with the remainder attributed to
artificial sources and are dominated by radiation in medicine.

The Fukushima Dai-ichi Nuclear Power Plant accident caused a release of radionuclides covering a significant area in Fukushima Prefecture, Japan. In the current work the radio-caesium
concentrations observed in some points of Namie Town between 2018. June. and 2019. September in river water, river sediment and aerosol are being presented. The observed concentrations were up to 205.9 ± 9 mBq/L for ¹³⁷Cs in unfiltered water and less than 4000 μBq/m3 for ¹³⁷Cs in air, while the sediment had a maximum of 4041 ± 2 Bq/kg-dry for ¹³⁷Cs. In many cases the water and aerosol samples had activity concentrations below the detection limit. These values decreased compared to the year 2017 for the same area. The potential yearly committed effective doses were estimated based on the data, with the calculated annual dose rates being well below any regulatory limit.

Mamuju is an area of Indonesia with high radiation exposure compared to the average across the country. It is included in the high background radiation area (HBRA) category. Radium-226
(²²⁶Ra) is one of the natural radionuclides that, if contained in drinking water, can be harmful to human health. Mamuju’s residents generally use well water for their daily needs. Radium-226 is
easily soluble in water and emits alpha particles. Therefore, measurement of ²²⁶Ra in drinking water is necessary to protect the public from radiation. A total of 13 drinking water samples were
obtained from the HBRA in Mamuju. They had a concentration range of 14–238 mBq L^－1. These concentrations are below the World Health Organization recommendation, which is 1 Bq L^－1, with an annual effective dose (mSv y^－1) from the ingestion of ²²⁶Ra in water ranging between 3–49 μSv.

Since the Fukushima Dai-ichi Nuclear Power Plant accident in 2011, background radiation dose monitoring was increased throughout Japan for public assurance. In Shimokita Peninsula of Aomori
Prefecture, several nuclear-related facilities are present. Background radiation monitoring data within nuclear facilities or selected residential areas in larger cities, measured by nuclear facilities or government agencies, is publicly available. To increase public involvement in radiation monitoring and encourage communication during non-emergency periods, a regional radiation monitoring project in places involved in radiation emergency response was launched in 2015. Background dose rate monitoring using personal dosimeter PM1904A POLISMART® II of four healthcare facilities and one municipal city office in Mutsu City and Higashidori Village determined the baseline level of outdoor background radiation from 2015 to 2018, which was an average of 0.0499 ± 0.011 μSv/h. Temperature, humidity, wind speed, accumulated snow and precipitation did not significantly affect dose rates measured with POLISMART. Although background dose rates measured by POLISMART were higher than those measured by monitoring posts and other detectors in similar locations and measurement periods, annual background radiation calculated from POLISMART measurements was lower than Japan’s estimated average of 0.7 mSv/yr. From these results, POLISMART may be additionally used for environmental radiation monitoring and public education.

We evaluated the enrichment factor of tritium for an improved solid polymer electrolyte (SPE) system. In this system, water sample reservoirs were made of double-glazed glass, and cooling
water was circulated in the double glass to cool the sample. As the result, a tritium enrichment factor of 5.00 was obtained and the MDL of tritium measurement with a low-background
liquid scintillation counter coupled to this improved enrichment process was determined to be approximately 0.062 Bq L^-1. Tritium concentration in monthly precipitation at Kumamoto was
measured using this method combining a low-background liquid scintillation counter and this improved SPE system.

Outdoor absorbed dose rates in air were evaluated in the environs of Eastern, Western, and Southern Thailand using the gamma-ray pulse height distribution obtained by in-situ NaI(Tl)
scintillation spectrometer, and by analyses of soil samples for ²²⁶Ra, ²³²Th, and ⁴⁰K activity concentration using an HPGe gamma spectrometry. The geometric mean values of the outdoor
gamma dose rates from the direct measurements and the soil analyses were 45 ± 8 nGy/h and 69 ± 3 nGy/h respectively. The ratio of the average absorbed dose rate in air inferred from the activity concentrations of radionuclides in soil to the average absorbed dose rate in air from the in-situ measurement in this study is 1.5.

The International Commission on Radiological Protection (ICRP) is a community of more than 250 globally-recognised experts in radiological protection science, policy, and practice from more
than 30 countries, and is also a charity. The objective of the system of radiological protection is to provide an appropriate level of protection for people and the environment against the harmful
effects of radiation exposure without unduly limiting the individual or societal benefits of activities involving radiation. This article briefly overviews the history of ICRP, the development of the
system of radiological protection, and the recent trends of its publications, especially from the viewpoint of medicine.