Occupational radiation dose on the hand of assisting medical staff in diagnostic CT scans.

Chronic radiation exposure increases the risk of skin damage of medical personnel engaged in radiology. However, hand dose measurements in computed tomography (CT) for diagnostic purposes have not been evaluated. The occupational radiation dose to the hands of CT assistants was herein investigated to evaluate its compliance with the equivalent dose limit for the hand (500 mSv/year). The occupational doses of nine CT assistants were measured in 89 cases (April 2017-May 2018) by installing radio-photoluminescence glass dosemeters (GD-302 M) (70-µm dose-equivalent conversion coefficient = 0.37) on the dorsal aspect of both hands. The occupational dose to the hand was the highest with head holding (right: 1.14 mSv/CT scan, left: 1.07 mSv/CT scan). Considering the results for annual work, even for head holding, the hand dose of the CT-assisting personnel was insignificant. However, CT assistants should be mindful of the possibility of locally higher doses to hands.

Estimation of inhomogeneous occupational exposure to the lens of the eyes and the extremities of radiation workers in a research accelerator facility.

We performed an experimental investigation on occupational exposure of the eye lens and the extremity of radiation workers engaged in handling of highly activated materials in a small research accelerator facility. Using a simplified physical phantom to simulate the relevant inhomogeneous radiation exposure situations, the personal dose equivalents obtained at the eye lens and the extremities of radiation workers handling heavily radioactive converters were measured together with the dose measured by personal dosemeters worn on their trunk. Results of mockup experiments and the Monte Carlo calculations suggest that the quantitative estimation of the eye lens doses can be estimated from the trunk dose, while the extremity doses vary considerably from the dose readings from the trunk, depending on the use of simple point-source or volume source geometry.

The spread of heated tobacco product (HTP) use across various subgroups during 2015-16 and 2017-18 in Japan.

BACKGROUND: Heated tobacco product (HTP) use has increased substantially between 2016 and 2017 in Japan. This study aims to clarify how HTP use (IQOS, Ploom, and glo) spread across the different combustible cigarette smoking statuses during 2015-16 and 2017-18 in Japan. METHODS: We compared the two periods of (i) 2015 to 2016 (N = 5,366) and (ii) 2017 to 2018 (N = 3,422) from a longitudinal study randomly sampling members from the Japan "Society and New Tobacco" Internet Survey (JASTIS). Multivariable logistic regression models for current HTP use in the previous 30 days by combustible cigarette smoking status in the previous year were used adjusting for socio-demographic factors. RESULTS: HTP use increased by 10 times in the 2017-18 cohort compared with the 2015-16 cohort according to the adjusted odds ratio (95% confidence interval) for current HTP use as 10.2 (7.03-14.8). According to smoking status, significantly higher adjusted ORs (95% CIs) of current HTP use for the after period were observed: 2.60 (1.37-4.94) for never smokers, 7.82 (3.64-16.8) for former smokers, 21.1 (5.73-77.9) for current smokers with intention to quit, and 17.0 (9.58-30.3) for current smokers without intention to quit. CONCLUSION: During 2015 to 2018 in Japan, HTP use dramatically increased in all subgroups except for never smokers.

The Effect of Pre-Operative Verbal Confirmation for Interventional Radiology Physicians on Their Use of Personal Dosimeters and Personal Protective Equipment.

Interventional radiology (IR) physicians must be equipped with personal passive dosimeters and personal protective equipment (PPE); however, they are inconsistently used. Therefore, we aimed to explore practical measures to increase PPE usage and ascertain whether these measures could lead to an actual decrease in exposure doses to IR physicians. Dosimeters and PPE were visually inspected. Then, a pre-operative briefing was conducted as a direct intervention, and the use of dosimeters and PPE was verbally confirmed. Finally, the intervention effect was verified by measuring the use rates and individual exposure doses. Because of the intervention, the use rate markedly improved and was almost 100%. However, both the effective dose rate (effective dose/fluoroscopy time) and the lens equivalent dose rate (lens equivalent dose/fluoroscopy time) showed that the intervention led to a statistically significant increase in exposure (effective dose rate: p = 0.033; lens equivalent dose rate: p = 0.003). In conclusion, the proper use of dosimeters and PPE raised the radiation exposure values for IR physicians immediately after the intervention, which was hypothesized to be due to the inclusion of exposure overlooked to date and the changes in the dosimeter management method from a single- to a double-dosimeter approach.

Association between Fathers' Use of Heated Tobacco Products and Urinary Cotinine Concentrations in Their Spouses and Children.

Heated tobacco products (HTPs) have become increasingly popular among smokers, especially among young adults in Japan in recent years. Assessments of secondhand tobacco smoke (SHS) exposure due to HTPs are scarce. The present study aimed to assess the urinary levels of total nicotine metabolites (TNMs) of non-smoking spouses and their children following SHS exposure due to their fathers' use of HTPs. A total of 41 families including 129 participants were recruited between 2018 and 2021. The number of non-smoking spouses and children of the fathers who smoke combustion cigarettes, the fathers who use HTPs, and the fathers who are non-users or have never smoked was 27, 66, and 36, respectively. The urinary levels of TNMs, including cotinine (Cot) and 3'-hydroxycotinine (3-OHCot), were measured using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The spouses and children of fathers who use HTPs had significantly higher levels of TNMs in their urine compared to those with fathers who were non-smokers or non-users. The current study is the first to assess SHS exposure due to HTP use, and to suggest the importance of strategies to prevent exposure to SHS from HTP use in public places and educational strategies to protect non-smokers from secondhand HTP aerosol exposure in households and other private places.

A multicenter study of radiation doses to the eye lenses of clinical physicians performing radiology procedures in Japan.

PURPOSE: We investigated occupational dose to the lens of the eye for physicians engaged in radiology procedures. We evaluated the potential for compliance with the new-equivalent dose limits to the lens of the eye. Further, a "multiple radiation protection" protocol was proposed according to the basic principles of occupational health, and its effectiveness was estimated. METHODS: Physicians engaged in radiology procedure at medical facilities in Japan were included in this study. The eye lens dose (3-mm dose equivalent: Hp (3)) for each participant was measured using a small radio-photoluminescence glass dosimeter mounted on lead glasses. Physicians were directed to procedure multiple radiation protection measures to evaluate their usefulness. RESULTS: The Hp (3) was reduced by multiple radiation protection in all physicians. In particular, the Hp (3) reduced from 207.7 to 43.2 µSv/procedure and from 21.6 to 10.2 µSv/procedure in cardiovascular internal physician and cerebrovascular physician, respectively, after the implementation of the proposed multiple radiation protection measures. The dose reduction rate of these measures was 53% (range: 37%-79%). CONCLUSIONS: The radiation doses received by the eye lenses of physicians engaged in radiology procedure may exceed the dose limits to the lens of the eye if radio-protective equipment and imaging conditions are not properly controlled. However, based on the lens equivalent dose data, the implementation of "multiple radiation protection" according to the basic principles of occupational health can ensure compliance with the new-equivalent dose limits to the lens of the eye without placing an undue burden on individual physicians or medical facilities.

Development and assessment of an educational application for the proper use of ceiling-suspended radiation shielding screens in angiography rooms using augmented reality technology.

PURPOSE: An augmented reality (AR) application to help medical staff involved in interventional radiology (IR) learn how to properly use ceiling-suspended radiation shielding screens was created, and its utility was tested from the perspective of learner motivation. METHOD: The distribution of scattered radiation in an angiography room was visualized with an AR application in three settings: when a ceiling-suspended radiation shielding screen is not used (incorrect); when there is a gap between the bottom edge of the shielding screen and the patient's torso (incorrect); and when there is no gap between the bottom edge of the shielding screen and the patient's torso (correct). This AR application was used by 33 medical staff, after which an Instructional Materials Motivation Survey (IMMS) based on the John Keller's ARCS (four categories of Attention, Relevance, Confidence, and Satisfaction) Motivation Model, consisting of 36-items with responses on a 5-point (1-5) Likert scale, was conducted. RESULTS: The overall score was a high 4.67 ± 0.30 (mean ± standard deviation). Physician's scores tended to be lower than those of other medical staff in the categories of Attention, Relevance, and Satisfaction (not statistically significant). CONCLUSIONS: The AR application to learn how to properly use ceiling-suspended radiation shielding screens was highly rated from the perspective of learner motivation.

Strategy to Reduce the Collective Equivalent Dose for the Lens of the Physician's Eye Using Short Radiation Protection Curtains to Prevent Cataracts.

A short curtain that improves on the low versatility of existing long curtains was developed as a dedicated radiation protective device for the over-table tube fluorographic imaging units. The effect of this short curtain in preventing cataracts was then examined. First, the physician lens dose reduction rate was obtained at the position of the lens. Next, the reduction rate in the collective equivalent dose for the lens of the physician's eye was estimated. The results showed that lens dose reduction rates with the long curtain and the short curtain were 88.9% (literature-based value) and 17.6%, respectively, higher with the long curtain. In our hospital, the reduction rate in the collective equivalent dose for the lens of the physician's eye was 9.8% and 17.6% with a procedures mixture, using the long curtain where technically possible and no curtain in all other procedures, and the short curtain in all procedures, respectively, higher with the short curtain. Moreover, a best available for curtains raised the reduction rate in the collective equivalent dose for the lens of the physician's eye a maximum of 25.5%. By introducing the short curtain, it can be expected to have an effect in preventing cataracts in medical staff.

Occupational radiation dose to the lens of the eye of medical staff who assist in diagnostic CT scans.

PURPOSE: We investigated occupational dose to the lens of the eye for CT-assisting personnel for diagnostic purposes using a radio-photoluminescent glass dosimeter (RPLD) and evaluate compliance with the new equivalent dose limit for the lens of the eye (20 mSv/year). Further, we proposed the implementation of "multiple protective measures" and estimated its effect. METHOD: An eye lens dosimeter clip was developed specifically to attach RPLDs inside radiation safety glasses in an L-shape. Using a total of six RPLDs attached to the radiation safety glasses, the 3-mm dose-equivalent (Hp(3)) to the lens of the eye for medical staff (n = 11; 6 intensive care physicians, 2 pediatricians, 3 radiological technologists) who assisted patients during CT scan for "diagnostic" purpose (n = 91) was measured. We evaluated the dose reduction efficiencies with radiation safety glasses and bag-valve-mask extension tube. We also estimated the protection efficiency with radiation protection curtain introduced in front of the staff's face via the phantom experiment. RESULTS: Without wearing radiation safety glasses, Hp(3) to the lens of the eye was greatest for intensive care physicians (0.49 mSv/procedure; allowing 40 procedures to be performed annually), followed by pediatricians (0.30 mSv/procedure; 66 procedures annually) and radiological technologists (0.28 mSv/procedure; 71 procedures annually). Use of each type of protective tools: radiation safety glasses (0.07-mm-Pb), bag-valve-mask extension tube (20 cm) and radiation protective curtain (0.25-mm-Pb), reduced Hp(3) to the lens of the eye by 51%, 31% and 61%, respectively. CONCLUSION: Intensive care physicians perform most assisted ventilations with the bag-valve-mask during "diagnostic" CT scans, and may exceed the equivalent dose limit for the lens of the eye if radiation safety glasses are not worn. If "multiple protective measures" are implemented, compliance with the equivalent dose limit for the lens of the eye should be achievable without placing significant burdens on physicians or medical institutions.

Indoor Formaldehyde Concentration, Personal Formaldehyde Exposure and Clinical Symptoms during Anatomy Dissection Sessions, University of Medicine 1, Yangon.

The formaldehyde (FA) embalming method, the world's most common protocol for the fixation of cadavers, has been consistently used in medical universities in Myanmar. This study was designed to examine the indoor FA concentrations in anatomy dissection rooms, an exposed site, and lecture theater, an unexposed control site, and to access personal exposure levels of FA and clinical symptoms of medical students and instructors. In total, 208 second year medical students (1/2019 batch) and 18 instructors from Department of Anatomy, University of Medicine 1, participated. Thirteen dissection sessions were investigated from February 2019 to January 2020. Diffusive sampling devices were used as air samplers and high-performance liquid chromatography was used for measurement of FA. Average indoor FA concentration of four dissection rooms was 0.43 (0.09-1.22) ppm and all dissection rooms showed indoor concentrations above the occupational exposure limits and short-term exposure limit for general population. Personal FA exposure values were higher than indoor FA concentrations and the instructors (0.68, 0.04-2.11 ppm) had higher exposure than the students (0.44, 0.06-1.72 ppm). Unpleasant odor, eye and nose irritations and inability to concentrate were frequently reported FA-related symptoms, and the students were found to have significantly higher risks (p < 0.05) of having these symptoms during the dissection sessions than during lecture.

Smoking and Long-Term Sick Leave in a Japanese Working Population: Findings of the Japan Epidemiology Collaboration on Occupational Health Study.

BACKGROUND: Few studies have investigated the association between tobacco smoking and sick leave (SL) in Japan. METHODS: We followed 70 896 workers aged 20-59 years (60 133 males, 10 763 females) between April 2012 and March 2017. A Cox proportional hazards model was used to investigate the associations between smoking (smoking status and intensity) and long-term SL (ie, SL lasting ≥30 consecutive days). Cause-specific analyses were also conducted. RESULTS: A total of 1777 people took long-term SL during a follow-up of 307 749 person years. Compared with never-smokers, current smokers were at a higher risk of long-term SL (hazard ratio [HR] = 1.32; 95% confidence interval [CI] = 1.19 to 1.48). Cause-specific analyses revealed that current smoking was associated with a higher risk of SL due to all physical disorders (HR = 1.44, 95% CI = 1.22 to 1.69), cancer (HR = 1.49, 95% CI = 1.10 to 2.01), cardiovascular disease (CVD; HR = 2.16, 95% CI = 1.31 to 3.55), and injuries/external causes (HR = 1.83, 95% CI = 1.31 to 2.58). Former smokers were at a higher risk of SL due to cancer at a borderline significance level (HR = 1.38, 95% CI = 0.99 to 1.92). Low-intensity smoking (ie, 1-10 cigarettes smoked per day) was associated with all-cause SL, SL due to CVD, and SL due to injuries/external causes compared with never-smokers. CONCLUSION: In a large cohort of working-age Japanese, smoking was associated with a greater risk of long-term SL. Greater effort is needed to mitigate disease burden associated with smoking at workplace in Japan. IMPLICATIONS: Our study contributes to the literature on the association between smoking and SL in several ways. First, the study was conducted among a Japanese working population. While the association has been extensively studied in Western setting, few attempts have been made elsewhere. Second, cause-specific analyses were undertaken in our study. Third, we paid attention to the effect of low-intensity smoking on SL given that there is growing evidence of an elevated health risk associated with low-intensity smoking.

Optimization of the Maximum Skin Dose Measurement Technique Using Digital Imaging and Communication in Medicine-Radiation Dose Structured Report Data for Patients Undergoing Cerebral Angiography.

Understanding the maximum skin dose is important for avoiding tissue reactions in cerebral angiography. In this study, we devised a method for using digital imaging and communication in medicine-radiation dose structured report (DICOM-RDSR) data to accurately estimate the maximum skin dose from the total air kerma at the patient entrance reference point (Total Ka,r). Using a test data set (n = 50), we defined the mean ratio of the maximum skin dose obtained from measurements with radio-photoluminescence glass dosimeters (RPLGDs) to the Total Ka,r as the conversion factor, CFKa,constant, and compared the accuracy of the estimated maximum skin dose obtained from multiplying Total Ka,r by CFKa,constant (Estimation Model 1) with that of the estimated maximum skin dose obtained from multiplying Total Ka,r by the functional conversion factor CFKa,function (Estimation Model 2). Estimation Model 2, which uses the quadratic function for the ratio of the fluoroscopy Ka,r to the Total Ka,r (Ka,r ratio), provided an estimated maximum skin dose closer to that obtained from direct measurements with RPLGDs than compared with that determined using Estimation Model 1. The same results were obtained for the validation data set (n = 50). It was suggested the quadratic function for the Ka,r ratio provides a more accurate estimate of the maximum skin dose in real time.

[Policy recommendation for the regulation of heated tobacco products based on evidence review of their health effects and influence on tobacco control].

Objective This report aimed to present policy recommendations on the regulation of heated tobacco products based on a review of the literature on the use of heated tobacco products, component analysis of harmful chemical substances, and product characteristics as nicotine delivery device, and on an examination of the influence of the product's increasing usage to the main measures of tobacco control.Methods The literature search was performed using Japan Centra Revuo Medicina and PubMED database. The search yielded 11 articles that examined the use of heated tobacco products, component analysis of harmful chemical substances, and product characteristics as nicotine delivery device. Eight articles were additionally collected from reports of public health research in Japan and public reports in foreign countries. The six main policies advocated by World Health Organization as MPOWER (Monitor, Protect, Offer, Warn, Enforce, Raise) were adopted in considering the expected influence of this product's increasing usage this product epidemic on tobacco control. In addition to the abovementioned 19 articles, 26 documents and materials related to the status of tobacco control were collected and used to examine the influence of the product's increasing usage to the main measures of tobacco control.Results In Japan, heated tobacco products have been available since December 2013, and the spread of use has risen remarkably since 2016. As of October 2016, Japan consumed more than 90% of the heated tobacco products sold internationally. Compared with cigarettes, heated tobacco products can reduce exposure to harmful substances except nicotine. However, their use does not lead to reduced risk of illness. The reduction of exposure to harmful substances cannot be expected when used in combination with cigarettes. Heated tobacco products and cigarettes have similar nicotine exposure levels and pharmacokinetics; thus, use of the former results in nicotine dependence and exacerbates the difficulty in discontinuing tobacco consumption. The popularity of heated tobacco products could adversely affect any of the six main measures of tobacco control.Conclusion Although public health concerns have been identified for the popularity of heated tobacco products, evidence remains insubstantial for the formulation of regulatory implications. Additional research is needed on the health effects to users and bystanders, effects on cigarettes use, and influence on tobacco control policy. From the perspective of the precautionary principle of public health, the same regulation as for cigarettes should be implemented as regards heated tobacco products until their health effects are fully elucidated.

Determination of Thermal Decomposition Products Generated from E-Cigarettes.

An electronic cigarette (e-cigarette) is a product used to smoke aerosol by heating a solution of "e-liquid" that consists of propylene glycol (PG) and glycerol (GLY) containing nicotine and flavors. In this study, thermal decomposition products generated from three brands of e-cigarettes were determined at various electric power levels. When using neat PG or GLY instead of e-liquid, propylene oxide was detected only in the gas phase from PG and not detected from GLY. In contrast, glycidol was detected only from GLY and not from PG. Almost all of the glyoxal and acrolein was detected from GLY, but formaldehyde and methyl glyoxal were detected from both PG and GLY. Using commercially available e-liquids, the same results were obtained. Nearly all chemical compounds generated from e-cigarettes have a carbon number of 3 or less except for nicotine and flavors. We measured chemical compounds generated from e-cigarettes at various electric power levels (1-85 W). At an electric power of 10 W, the generation of chemical compounds was very low; however, when the electric power exceeded 40 W, it increased exponentially. As thermal decomposition products of e-liquid, acetaldehyde, acrolein, and propylene oxide mainly occur as gaseous matter, while glyoxal, methylglyoxal, and glycidol mainly occur as particulate matter. Formaldehyde exits in both gaseous and particulate matter forms. Thermal decomposition products can be divided into three groups: thermal decomposition products originating from PG and GLY, those originating from other sources, and those directly generated. Concentrations of these thermal decomposition products were mostly higher than those in traditional cigarettes. In particular, thermal decomposition products generated from one of the studied e-cigarettes were very high; e.g., formaldehyde reached 4400 µg/15 puffs at 50 W. E-cigarette users must know that hazardous substances are generated even within the recommended electric power limits.

Smoking cessation after long-term sick leave due to cancer in comparison with cardiovascular disease: Japan Epidemiology Collaboration on Occupational Health Study.

In occupational settings, smokers may take quitting smoking seriously if they experienced long-term sick leave due to cancer or cardiovascular disease (CVD). However, no study has elucidated the smoking cessation rate after long-term sick leave. We examined the smoking cessation rate after long-term sick leave due to cancer and CVD in Japan. We followed 23 survivors who experienced long-term sick leave due to cancer and 39 survivors who experienced long-term sick leave due to CVD who reported smoking at the last health exam before the leave. Their smoking habits before and after the leave were self-reported. Logistic regression was used to calculate adjusted smoking cessation rates. Smoking cessation rate after long-term sick leave due to cancer was approximately 70% and that due to CVD exceeded 80%. The adjusted smoking cessation rate was 67.6% (95% confidence interval [CI]: 47.0, 88.2) for cancer and 80.7% (95% CI: 67.7, 93.8) for CVD. Smoking cessation rate after a longer duration of sick leave (≥60 d) tended to increase for both CVD and cancer. Although any definite conclusion cannot be drawn, the data suggest that smoking cessation rate after long-term sick leave due to CVD is slightly higher than that for cancer.

Association between anthropometric indices of obesity and risk of cardiovascular disease in Japanese men.

OBJECTIVES: We aimed to compare the association of body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) with risk of cardiovascular disease (CVD) among middle-aged working Japanese men. METHODS: A nested case-control study was performed among middle-aged male employees who underwent periodic health checkup. A total of 241 CVD cases were identified and matched individually on age, gender, and worksite with 1205 controls. Data on BMI, WC, WHtR, smoking, hypertension, diabetes, and dyslipidemia collected at 4 years before the event/index date were retrieved. Associations between BMI, WC, WHtR, and CVD risk were assessed by using conditional logistic regression models. RESULTS: The strength of the association of BMI, WC, and WHtR with CVD risk was similar. The smoking-adjusted odds ratio (95% confidence interval) for CVD was 1.60 (1.38-1.85), 1.53 (1.33-1.78), and 1.56 (1.35-1.81) for a 1 SD unit increase in BMI, WC, and WHtR respectively. After further adjustment for hypertension, diabetes, and dyslipidemia, these associations were attenuated but remained statistically significant. CONCLUSIONS: Measures of general (BMI) and abdominal (WC and WHtR) obesity were similarly associated with CVD in middle-aged Japanese men.

Changes in oxidative stress levels during two weeks of smoking cessation treatment and their association with nutritional characteristics in Japanese smokers.

Although several experimental studies have reported that oxidative stress levels decrease during smoking cessation, how they change among general smokers has yet to be completely elucidated. In the present study, a total of 23 smokers who underwent smoking cessation treatment were observed for two-week changes in their levels of 8-OHdG and 8-isoprostane. Physical and nutritional characteristics were measured at the initial patient visit, and casual urine samples were collected at the initial visit and at a follow-up visit two weeks later. Oxidative stress was measured by a high performance liquid chromatography electrochemical detector, and the two-week difference in the levels of oxidative stress was assessed according to demographic and nutrient factors. Neither the urinary level of 8-OHdG nor that of 8-isoprostane decreased, although the cotinine level was decreased at two weeks. A Two-way repeated ANOVA revealed a significant interaction for fat intake by time for the change in the 8-OHdG level (P=0.03) and significant interactions for α-tocopherol intake (P=0.03), iron intake, and carbohydrate intake (P=0.03), all of which were time-dependent for the change in the 8-isoprostane level. The 8-OHdG level decreased among smokers with a high fat intake and was increased with a low fat intake. The 8-isoprostane levels were decreased among smokers with a high carbohydrate intake and increased with a low carbohydrate intake, decreased with a low iron intake and increased with a high iron intake and decreased with a low α-tocopherol intake and increased with a high α-tocopherol intake. Although the present study failed to observe a decrease in oxidative stress levels during the two-week smoking cessation period, we hypothesize that the intake levels of specific nutrients when initiating smoking cessation treatment may predict any subsequent changes in the oxidative stress levels.

Epicatechin as a promising agent to countermeasure radiation exposure by mitigating mitochondrial damage in human fibroblasts and mouse hematopoietic cells.

Accidental radiation exposure that is due to a nuclear accident or terrorism using radioactive materials has severe detrimental effects on human health, and it can manifest as acute radiation syndrome depending on the dose and distribution of the radiation. Therefore, the development of radiation countermeasure agents is urgently needed to protect humans against radiation injury. Besides nuclear DNA, the mitochondria are important targets of ionizing radiation (IR) because these organelles generate reactive oxygen species (ROS). Recently, we revealed that mitochondrial ROS-activated cell signaling is associated with IR-induced tumor formation. Here, we investigated the effectiveness of ascorbic acid and epicatechin (EC) in scavenging ROS as radiation countermeasure agents by using human cells and mouse. Preradiation and postradiation treatments with EC mitigate ROS-mediated mitochondrial damage, IR-induced oxidative stress responses including reduction of superoxide dismutase activity, and elevated nuclear factor erythroid 2-related factor 2 expression, and they improve human fibroblast survival. As well as in vitro, EC mitigated ROS-mediated mitochondrial damage after exposure to IR in vivo in mouse platelets. Furthermore, oral administration of EC significantly enhanced the recovery of mouse hematopoietic cells from radiation injury in vivo. In summary, EC is a potentially viable countermeasure agent that is immediately effective against accidental IR exposure by targeting mitochondria-mediated oxidative stress.-Shimura, T., Koyama, M., Aono, D., Kunugita, N. Epicatechin as a promising agent to countermeasure radiation exposure by mitigating mitochondrial damage in human fibroblasts and mouse hematopoietic cells.