Thyroid 123I imaging systems using an imaging plate (IP) and collimators were devised.Three collimators for highsensitive, standard, and high resolution IP systems were handcrafted.The overall spatial resolutions of the IP systemsand gamma camera were 8.2, 4.8, 2.8, and 4.8 mm, respectively.The lower detection limits of the high sensitive, standard and high resolution IP systems and gamma camera were 10, 190, 750 and 525 kBq, respectively.Thesensitivities of these IP systems were 52.5, 2.8, and 0.7 times as high as that of the gamma camera.The administeredactivity can be reduced to about 2% for the gamma camera by using the high sensitive IP system which is optimal forinfant examinations.The standard IP system is suitable for routine examinations.The high resolution system isadequate for detailed examinations of thyroid glands.Thyroid imaging can be conducted wherever and wheneverneeded due to the portable advantages.
Gene expression profile of yeast in response to extremely low frequency electromagnetic fields (ELF-MF) wasinvestigated by means of DNA microarray.Sixty-seven ORFs were up-regulated and 122 ORFs were down-regulated.The UBC4 gene was up-regulated.Ubc4p participates in the degradation of denatured proteins.This suggests thatdenaturation or premature of proteins may occur as a result of ELF-MF exposure.Interestingly, RAD50, which isinvolved in DNA damage repair, is also induced by ELF-MF exposure.Moreover, DPB11, SLD3 and PES4, which areinvolved in DNA replication by DNA polymerase ε, were down-regulated by ELF-MF exposure.
A method for identifying 14C from 35S having very near maximum energies was devised by using a GM counterand thin absorbers.Differentiation was conducted by using attenuation rates of 14C and 35S in a low energy regionwithout determining their maximum ranges.35S can be discriminated from 14C by measuring twice.
The computer program TriStat was applied to estimate the dose to a representative Japanese due to a stationaryrelease of tritium as HTO and/or HT to the atmosphere from nuclear facilities.In TriStat, the air tritiumconcentration is estimated by a Gaussian dispersion model.The tritium deposition to the soil was assumed to occurboth by dry and wet deposition processes of atmospheric tritium. The primary process of tritium transfer to humanbody is assumed to take place through a local food-chain in the contaminated area. Tritium concentrations in soil, vegetables and forage were estimated as the tritium concentration per waterequivalent.The food chain was modeled by assuming a vegetable compartment and an animal-food compartment. By using TriStat the annual dose to the representative Japanese was evaluated for stationary release of tritium asa function of the distance from a release point.The dose contribution from drinking water was neglected, since thedrinking water is generally supplied as tap water or as commercial bottled water.In the case of HT release, thecommitted dose due to tritium intake through breathing and skin absorption was found to be of minor importance.