The deposition densities of radiocesium and the air dose rates in undisturbed fields around the Fukushima Dai-ichi nuclear power plant; their temporal changes for five years after the accident

The deposition densities of radiocesium and the air dose rates were repeatedly measured in a large number of undisturbed fields within the 80 km zone that surrounds the Fukushima Dai-ichi Nuclear Power Plant site between 2011 and 2016, and features of their temporal changes were clarified. The average air dose rate excluding background radiation in this zone decreased to about 20% of the initial value during the period from June 2011 to August 2016, which was essentially a result of the radioactive decay of ¹³⁴Cs with a half-life of 2.06 y. The air dose rate reduction was faster than that expected from the decay of radiocesium by a factor of about two, with most of this reduction being attributed to the penetration of radiocesium into the soil. The average deposition densities of ¹³⁴Cs and ¹³⁷Cs in fields that were not decontaminated were found to have decreased nearly according to their expected radioactive decay, which indicated that the movement of radiocesium in the horizontal direction was relatively small. The effect of decontamination was apparently observed in the measurements of air dose rates and deposition densities. Nominally, the average air dose rates in the measurement locations were reduced by about 20% by decontamination and other human activities, of which accurate quantitative analysis is and continue to be a challenge. In this paper, new original data obtained during 2013-2016 were added to the previously reported data collected up to 2012, and it is discussed throughout.

Transport and Redistribution of Radiocesium in Fukushima Fallout through Rivers

The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released the most significant quantity of radiocesium into the environment since Chernobyl, and detailed measurements over the initial 5 years provide new insights into fluvial redistribution of radiocesium. We found that the high initial activity concentration of ¹³⁷Cs-bearing suspended sediment in rivers was followed by a steep exponential decline (λ₁) which extended to approximately 1 year after the accident, while the rate of initial decline in radiocesium activity concentration in water was an order of magnitude higher than rates measured after Chernobyl. Fluvial transport of ¹³⁷Cs to the ocean from the Abukuma river totaled 12 TBq between June 2011 and August 2015 and almost all this radiocesium (96.5%) was transported in the particulate form. The primary sources of ¹³⁷Cs were paddy fields, farmland, and urban areas [plaque-forming unit (PFU)], discharging 85% of the exported ¹³⁷Cs from 38% of the watershed area. After 1 year, activity concentrations were lower and exhibited a more gradual secondary decline (λ₂) which was associated with reduced radiocesium losses from PFU areas, while forest areas continue to represent more stable contaminant stores.

P5616Risk stratification of cardiovascular events among patients with functionally non-significant coronary stenosis

Introduction

Deferral of percutaneous coronary intervention (PCI) of a functionally non-significant stenosis is associated with a favorable long-term clinical prognosis. However, to date, there has been limited evidence to stratify the risk for the development of cardiovascular (CV) adverse events in patients who were deferred of PCI due to a greater fractional flow reserve (FFR) than 0.80 at the target lesion.

Purpose

We aimed to stratify the risk of CV events in patients with functionally significant and non-significant coronary stenosis.

Methods

This observational study included 458 patients who were proven angiographically intermediate coronary stenoses and were measured FFR, of whom 298 deferred patients with FFR>0.80 and 160 intervened patients with FFR<0.80. The primary endpoint was the incidence of major adverse cardiac and cerebrovascular events (MACCE) including any death, non-fatal myocardial infarction, hospitalization due to heart failure, ischemic stroke and any unplanned revascularization. ROC curve for MACCE indicated the cut-off point of FFR as 0.85 and 0.76 in deferred patients and intervened patients, respectively.

Results

During the observation period, 27 MACCE (9.1%) in the Deferred group, and 33 MACCE (20.6%) in Intervened group were occurred. Kaplan-Meier curves showed a higher MACCE rate in the Intervened group than Deferred group (hazard ratio (HR): 2.19, 95% confidence interval (CI): 1.29–3.71, Figure A). However, even among patients in the Deferred group, the population with “intermediate” FFR (0.81–0.85) had a significantly higher MACCE rate than those with higher FFR (>0.85) (HR 2.55, 95% CI 1.14–5.69, Figure B). This rate was comparable to that of the Intervened group at the remote phase (at 4-year: 32.0% vs. 35.8%). Conversely, in the Intervened group, there was no statistically significant difference in MACCE rate between patients with higher FFR (0.76–0.80) and those with lower FFR (<0.76) (Log-rank: p=0.21, Figure C).

Conclusion

The population with relatively low FFR in patients who were deferred PCI by FFR>0.80 had comparable MACCE rate to patients with FFR<0.80. Close observation after the FFR evaluation should be considered in those population.

P4453Predictors of sustained ventricular arrhythmias during late phase in patients with reduced left ventricular ejection fraction after myocardial infarction

Background

Sustained ventricular arrhythmias (VAs) and death are feared events post myocardial infarction (post-MI). Patients with heart failure post-MI have higher risk of VAs, compared to those without heart failure. Although the risk of sudden cardiac arrest and death post-MI isn't small, previous clinical trials have failed to demonstrate the benefit of early use of implantable cardioverter defibrillators. Moreover, little is known about the relationship between the acute phase and the late phase VAs in patients with heart failure post-MI.

Purpose

The aim of this study was to determine the predictors of the late phase VAs in patients with heart failure post MI.

Methods

We retrospectively analyzed our database of MI patients from January 2012 to September 2016.

Results

A total of consecutive 460 post-MI patients were included in this study (age, 67±12 year-old; male, 336 (73%); STEMI, 281 (61%)). All the patients underwent primary percutaneous coronary intervention. Of those, 90 patients (20%) had depressed left ventricular ejection fraction (LVEF) ≤35%. After a mean follow up period of 30±16 months, 45 patients (50%) had VAs after MI. Among them, 35 patients (78%) had VAs within 48 hours after MI onset, 8 patients (18%) within 7 days 48 hours later, and 21 patients (47%) more than 7 days. Cox-regression analysis showed that VAs within 7 days 48 hours later after MI onset was significantly related to sustained VAs more than 7 days after MI onset (Hazard Ratio, 4.97; 95% Confidence Interval, 1.31–18.9; p=0.019).

Conclusions

VAs in the sub-acute phase after MI predicted sustained VAs in the late phase in this population. Prompt initiation of aggressive antiarrhythmic therapies, including catheter ablation, after MI should be considered to reduce the mortality.

IMPACT ON ABSORBED DOSE RATE IN AIR IN KANTO REGION BY FUKUSHIMA DAIICHI NUCLEAR POWER PLANT ACCIDENT

Absorbed dose rates in air were measured for the whole area of the Kanto region in 2015, 2016 and 2017 (n = 31 147). The mean absorbed dose rates in air for each prefecture measured by car-borne surveys were from 44 to 67 nGy h-1 (13-289 nGy h-1). The absorbed dose rate in air from artificial radionuclides (134Cs + 137Cs) measured by fixed-point observation (n = 507) was from 1 to 14 nGy h-1 (0-105 nGy h-1), and meaning that the contribution ratios of 134Cs and 137Cs were 3-22%. The deposited location of artificial radionuclides was less than 1000 m from ground level and depended on the topography, wind direction and precipitation field.

Spatial properties of soil analyses and airborne measurements for reconnaissance of soil contamination by 137Cs after Fukushima nuclear accident in 2011

Following Fukushima nuclear disaster, several data gathering campaigns surveyed the radionuclide propagation in the environment. However, the acquired datasets do not have the same sampling dimension. For example, the airborne measurements are some sort of averaging over a circular field of view, beneath the sensor; while the soil analyses are much more punctual. The objective of this work is to compare the soil samples and an airborne survey to investigate whether these two datasets reflect the same spatial patterns or not. This is prerequisite for combining the multiresolution data to create and update the contamination map in a post-accidental situation. The analyses were performed on square tiles of 20 km side to study large- and small-dimension variations in ¹³⁷Cs deposition. The former was modelled by fitting a plane (called trend) to the georeferenced data points; and the latter was modelled by computing the difference (called residual) between the trend and the initial data. Dip direction and dip angle of trends as well as minimum spatial correlation distance and anisotropy of residuals were computed for both the soil and airborne datasets and compared. Dip directions are compatible in 73% of the tiles and dip angles are generally close. Anisotropy directions are compatible in 49% of the tiles and minimum spatial correlation distances are significantly more marked for the airborne dataset. The soil samples and airborne measurements are therefore more in agreement in large-dimension (trend) rather than in small-dimension (residual) variations. More generally, both the datasets allow highlighting the main contamination plumes distinguishable because of high concentration values. The airborne dataset yet appears to be more powerful to quantify spatial correlations, which could be linked to the contamination mechanisms.

Abstract P6-17-06: Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload

Background: Several classes of anti-cancer agents including certain immunotherapies, systemic chemotherapies, and targeted therapies including trastuzumab and T-DM1 increase the risk of interstitial lung disease (ILD) and fatal cases have been reported. For DS-8201a, interim efficacy and safety analyses of available data established a final recommended dose of 5.4 mg/kg IV q3wk in advanced HER2-positive breast cancer (BC). Based on preliminary clinical results, ILD was identified as an important risk for DS-8201a. A robust monitoring and management plan was established across all studies and an international, independent ILD adjudication committee (AC) reviews the cases reported as ILD on an ongoing basis.

Methods: All subjects (sbj) who received ≥1 dose of DS-8201a across 7 ongoing studies were included in this analysis. Reported ILD (standardized MedDRA Query terms) included the terms ILD, pneumonitis, and organizing pneumonia. ILD frequencies were calculated based on investigator's assessment and after adjudication. The analysis of potential risk factors associated with ILD is ongoing.

Results: As of 21 June 2018, 448 sbj received ≥1 dose of DS-8201a across multiple tumor types, including BC. Of the 321 sbj with BC, 173 (53.9%) were from Japan, 103 (32.1%) from the US, and 45 (14.0%) from 6 other countries (Spain, South Korea, Taiwan, Belgium, France, and Italy). These sbj received 1 of 7 doses of DS-8201a (0.8 mg/kg: 3 sbjs, 1.6 mg/kg: 1 sbj, 3.2 mg/kg: 3 sbjs, 5.4 mg/kg: 111 sbjs, 6.4 mg/kg: 178 sbj, 7.4 mg/kg: 20 sbj, 8.0 mg/kg: 5 sbj). Overall, 44 cases of potential ILD were reported by the investigators across all tumor types (44/448, 9.8%; Grade ≥3 10/448, 2.2%). In sbj with BC who received 5.4 mg/kg, any grade and Grade ≥3 investigator-reported ILD were 7.2% (8/111) and 0.9% (1/111), respectively. The ILD AC assessed 30 of 44 cases; 22 were considered drug-related ILD, 4 were ILD but not drug-related, and 4 were found not to be ILD. For adjudicated drug-related ILD cases, the median time to onset was 159 (range; 46-591) days from the time of first dose.

  Grade 1 Grade 2 Grade 3 Grade 4 Grade 5 All Grades All tumors, All doses (N=448)      Investigator-reported20 (4.5)14 (3.1)4 (0.9)1 (0.2)5 (1.1)44 (9.8)Cases adjudicated13840530Adjudicated as drug-related ILD9 (2.0)6 (1.3)3 (0.7)04 (0.9)22 (4.9) BC, All doses (N=321)      Investigator-reported17 (5.3)11 (3.4)3 (0.9)1 (0.3)4 (1.2)36 (11.2)Cases adjudicated11830426Adjudicated as drug-related ILD8 (2.5)6 (1.9)3 (0.9)04 (1.2)21 (6.5) BC, 5.4 mg/kg (N=111)      Investigator-reported4 (3.6)3 (2.7)001 (0.9)8 (7.2)Cases adjudicated120014Adjudicated as drug-related ILD00001 (0.9)1 (0.9)n (%), except where noted

Conclusions: These analyses confirm that ILD is an important identified risk for DS-8201a. Further analyses are ongoing to better understand the potential risk factors associated with the incidence of on-treatment ILD. When ILD is suspected, early diagnosis through appropriate imaging, laboratory tests, and pulmonary consultation as well as prompt management with steroids are recommended.

Citation Format: Powell CA, Camidge DR, Gemma A, Kusumoto M, Baba T, Kuwano K, Bankier A, Kiura K, Tamura K, Modi S, Tsurutani J, Doi T, Iwata H, Krop IE, Zhang L, Jasmeet S, Saito K, Shahidi J, Yver A, Takahashi S. Characterization, monitoring and management of interstitial lung disease in patients with metastatic breast cancer: Analysis of data available from multiple studies of DS-8201a, a HER2-targeted antibody drug conjugate with a topoisomerase I inhibitor payload [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-17-06.

Photocuring of 4-arm coumarin-functionalised monomers to form highly photoreversible crosslinked epoxy coatings

Highly photoreversible photocurable crosslinked epoxy coatings that can heal substantial surface damage were formed by the synthesis of unique monomers.

Decreasing trend of ambient dose equivalent rates over a wide area in eastern Japan until 2016 evaluated by car-borne surveys using KURAMA systems

As part of the investigation of the distribution of ambient dose equivalent rates around the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), car-borne surveys using Kyoto University RAdiation MApping (KURAMA) systems have been conducted over a wide area in eastern Japan since 2011. The enormous volume of measurement data collected until 2016, including those until 2012 which were reported in the previous paper, was analyzed, and dependencies of the decreasing trend of the dose rates in regions within 80 km of the FDNPP on land-use categories, evacuation order areas and magnitude of the dose rates were examined. The air dose rates within 80 km of the FDNPP tended to decrease considerably with respect to the physical decay of radiocaesium. The decrease of the dose rate in the "forest" was slower than its decrease in other regions, while that in "urban area" was the fastest. The decrease in the air dose rate from 2011 was the fastest outside the evacuation order area until 2015, and it was the slowest in the "difficult-to-return zone". However, the decreasing trend starting from 2013 showed that the decrease in the "zone in preparation for the lifting of the evacuation order" and in the "residence restriction area" was the fastest. It was found that the air dose rates decreased depending on the magnitude of the dose rates and elapsed time from the FDNPP accident, i.e. the decrease in air dose rates in areas with relatively low dose ranges (such as 0.2-0.5 μSv/h) was the largest during a period relatively early after the accident, and the decreasing rate in the dose rate ranges of 1.9-3.8 and 3.8-9.5 μSv/h were the fastest after 2013. The averaged ratios were analyzed to obtain the ecological half-lives of the fast and slow decay components, and those in whole area within 80 km of FDNPP were estimated to be 0.44 ± 0.05 y and 6.7 ± 1 y, respectively. The ecological half-lives with respect to the land use categories, evacuation order areas and magnitude of the dose rates were also evaluated. The decrease in the dose rates obtained by the car-borne survey was larger than that obtained on flat ground with few disturbances using the NaI(Tl) survey meter during approximately 1.5 y after the FDNPP accident. Thereafter, the difference of decreasing tendencies in the air dose rates between both the measurements was negligibly small, with the ratio of dose rates by the car-borne survey to those by the fixed-point measurement of 0.72-0.77.

Measurement of ambient dose equivalent rates by walk survey around Fukushima Dai-ichi Nuclear Power Plant using KURAMA-II until 2016

Ambient dose equivalent rates in various environments related to human lives were measured by walk surveys using the KURAMA-II systems from 2013 to 2016 within an 80-km radius of the Fukushima Dai-ichi Nuclear Power Plant. The dose rate of the locations where the walk survey was performed decreased to about 38% of its initial value in the 42 months from June 2013 to the December 2016, which was beyond that attributable to the physical decay of radiocaesium. The ecological half-life of the slow decreasing component was evaluated to be 4.1 ± 0.2 y. The air dose rates decreased depending on the level of the evacuation areas, and the decrease in the dose rates was slightly larger in populated areas where humans are active. The dose rates as measured by walk surveys exhibited a good correlation with those by car-borne surveys, suggesting that car-borne survey data are reflecting the air dose rates in living environments surrounding roads. The comparison of walk survey data with car-borne survey data indicated that the air dose rate varies largely even within a 100 m square area, and the variation is enhanced by human activities. The dose rates measured by the walk surveys were estimated to be medial of those along roads and those of undisturbed flat ground, and they were found to be decreasing quickly compared with the air dose rate from the flat ground fixed-point measurements.