Verification of linear energy transfer optimized carbon-ion radiotherapy.

Linear energy transfer (LET) verification was conducted using a silicon-on-insulator (SOI) microdosimeter during the commissioning of LET-optimized carbon-ion radiotherapy (CIRT). This advanced treatment technique is expected to improve local control rates, especially in hypoxic tumors.An SOI microdosimeter with a cylindrical sensitive volume of 30m diameter and 5m thickness was used.

Development of an externally controllable sealed isotope generator.

An externally controllable sealed isotope generator has been proposed for radiation education activities. Column (Ge-Ga and Cs-Ba) and solvent extraction (Ge-Ga)-based isotope generators were applied as radioactive sources. These generators showed high milking efficiencies and low breakthrough after repeated uses, and are expected to promote the use of isotope generators without radioactive contamination or the emission of radioactive waste.