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Proton computed tomography (CT) is an imaging technique using a high-energy proton beam penetrating the human body and shows promise for improving the quality of cancer therapy with high-energy particle beams because more accurate electron density distribution measurements and in-situ positioning can be achieved with proton CT. The deterioration of the spatial resolution owing to multiple Coulomb scattering is saved by reconstructing the proton trajectory. We have developed a prototype system for proton CT and demonstrate a precise measurement of electron density and an improvement in spatial resolution. In order to control of the radiation dose and reduce the exposure time for imaging, the precise position detector should work with very high rate (a few MHz). We have developed high speed tracker with large area silicon strip detector, Amplifier-Shaper-Discriminator LSI, which was developed for drift chamber readout at high energy physics experiment, and FPGA. We report the performance of the tracker evaluated with very high intensity proton beam for the cancer therapy.

After the cataclysmic explosion in the Fukushima Daiichi Nuclear Power Station triggered by the Great East Japan Earthquake of March 2011, more than 100,000 citizens living within 20km of the nuclear power station were evacuated. These residents were not allowed to return home for more than a year, until April 2012, when the Japanese government began to lift the evacuation order for some areas. As local governments contemplate strategies to revive these communities, a lingering question remains: how safe is it to live here? Answering this question is difficult for a number of reasons. Our project aims to provide data to allow individuals and communities to make their own assessments. The Radioisotope Center (RC) in Niigata University has built a vehicle-mounted radiation monitoring system consisting of a real-time GPS receiver, a dosimeter, and a laptop. This tool allows government officials in the affected municipalities to continuously measure airborne radiation levels. RC has partnered with the Institute for Digital Research and Education (IDRE) from the University of California, Los Angeles (UCLA) to develop a public web-based interface to this data to inform citizens about radiation levels in their communities. Both of these tools enable gathering and making data available to the general public more easily, and allow the public to make informed decisions about the safety of the decontaminated zones in the absence of widely-accepted standards.