Estimation of radioactivity in single photon emission computed tomography for sentinel lymph node biopsy in a torso phantom study

Objectives: Number of lymph nodes to be removed are determined from residual counts. Estimating residual radioactivity in lymphatic nodes before a biopsy in advance is useful for reducing surgical operation time. The purpose of this study was to estimate total radioactivity of a small hot spot in single-photon emission computed tomography (SPECT) of a torso phantom. Methods: Cross-calibration study was performed to convert counts in SPECT images to radioactivity. A simulation study was performed to estimate the size of volume of interest (VOI) covering a hot spot corrupted with full width at half maximum (FWHM) between 8 and 16 mm. The estimation of total radioactivity was validated in a torso phantom study using small sources. Results: True radioactivity was approximately equal to integrated values of hot spots using the VOI with a diameter of 40 mm in our simulation study. The difference was less than18% in cases of more than 9.4 kBq. Conclusions: The total radioactivity in small sources simulating a typical sentinel node was estimated from SPECT images using a VOI of 40 mm in a torso phantom study. Because the difference from actual values were less than 10% on average when radioactivities were more than 9.4 kBq, the total radioactivity of a lymph node can be estimated in a clinical examination

The right place to grow rice for the Japanese market: comparative analysis of greenhouse gas emissions of rice cultivation in Japan and the United States

One consequence of increasing agricultural trade is a shift of geographic location of agricultural activity to more economically productive countries. Whether or not the economic efficiency translates to environmental efficiency for agricultural goods is an open question. To examine environmental implications of shifting agricultural location, we analysed the life-cycle greenhouse gas (GHG) emissions of rice production in Japan and the US for the Japanese market in a comparative manner. This paper presents the life-cycle assessment of brown japonica rice. Our computation of GHG emissions of rice production in Japan and the US were 3.54 and 2.99 kgCO2-eq kg-rice−1, respectively. With respect to harvested area, the emissions were 18.4 in Japan and 27.8 tCO2-eq ha−1 in the US. For Japan to be environmentally competitive with the US production, fundamental restructuration of field size is necessary to increase yield. In conclusion, economic efficiency does not translate to environmental efficiency with the case of rice production. Importing rice is both economically and environmentally viable option for the Japanese market

Mortality Sensitivity of Cardiovascular, Cerebrovascular, and Respiratory Diseases to Warm Season Climate in Japanese Cities

We investigated decadal (2010–2019) cardiovascular, cerebrovascular, and respiratory mortality sensitivity to annual warm temperatures in major Japanese cities: Sapporo, Tokyo (23 wards), and Osaka. The summer mortalities (June–August) increased with the monthly mean temperature for acute myocardial infarction, other acute ischemic heart diseases, cerebral infarction, and pneumonia in the three cities. Monthly mean temperatures were an indicator of these disease mortalities in Japan. However, similar responses were not found for cardiac arrhythmia and heart failure (excluding Sapporo), subarachnoid hemorrhage, and intracerebral hemorrhage. The decadal sensitivities and risk ratios between the maximum and minimum monthly mean temperatures were calculated using a linear regression model. In Sapporo, Tokyo, and Osaka, for example, the analyses of acute myocardial infarction showed summer positive responses of 0.19–0.25, 0.13–0.18, and 0.12–0.30, respectively, as the mortality rate (per 100,000 population) per 1 °C of monthly mean temperature, which estimated increased risks (between the coolest and hottest months) of 37–65% in Sapporo, 31–42% in Tokyo, and 35–39% in Osaka

Simulation-Based Evaluation of the Effect of Green Roofs in Office Building Districts on Mitigating the Urban Heat Island Effect and Reducing CO₂ Emissions

This study focused on the effects of green roofs in office building districts. The purpose of this study was to evaluate the effectiveness of green roofs in the reduction of the urban heat island (UHI) effect and CO2 emissions. These effects consider decreased energy consumption for space cooling, and the amount of water needed for evapotranspiration on the green roofs. A coupled urban canopy/building energy model (CM-BEM) was utilized to simulate the effectiveness of green roofs. The amount of water needed for evapotranspiration was calculated by using latent heat flux, which was derived from the results of roof surface heat balance calculations. The effect of green roofs on CO2 emissions was determined based on their effectiveness to reduce the energy demand for space cooling, calculated by air-conditioning load simulation. We calculated the CO2 emissions from powering the pumps and the use of tap water, when the necessary amount of water was supplied by watering. Finally, the relationships between amount of water, UHI mitigation, and CO2 emissions were determined

Estimation of Direct and Indirect Household CO2 Emissions in 49 Japanese Cities with Consideration of Regional Conditions

We conducted a detailed estimation of direct and indirect CO2 emissions related to multi-person households in 49 Japanese cities. Direct energy consumption was decomposed into energy use in order to consider the relationship with regional conditions. The results showed that CO2 emissions from direct energy consumption were almost as large as indirect CO2 emissions induced by consuming products and services, suggesting that lifestyle improvements are important for both energy savings and reducing CO2 emissions relating to product and service consumption. In addition, CO2 emissions from direct energy consumption varied widely between cities, making them susceptible to regional conditions. We also calculated CO2 emissions from direct energy consumption and examined the regional conditions for individual forms of energy use. CO2 emissions were higher in cold regions and lower in larger cities. In Japan, large cities are often located in relatively warm areas, so we conducted an analysis to distinguish the effects of climatic conditions from those of urbanization. This analysis allowed us to clarify the effects of regional conditions on factors such as heating/cooling and the ratio of detached houses to apartments