Research by the National Institutes for Quantum and Radiological Science and Technology, Tohoku University, Japan Atomic Energy Agency, etc. has made it possible to visualize the movement of cesium in living animals.
Since the accident at TEPCO's Fukushima Daiichi Nuclear Power Station, much research has been done on the biodynamic model until the radioactive cesium released into the environment is absorbed and discharged into the body.If the movement of radioactive cesium taken into the body can be tracked, it will be useful for understanding the effects of internal exposure and elucidating the mechanism of cesium excretion from the living body.
Therefore, in this study, we worked on the production of a positron-releasing nuclide cesium (Cs-127) tracer for tracing the movement of cesium taken into the body. Cs-127 is one of the isotopes of cesium, and it behaves in the same way as Cs-134 and Cs-137 generated by nuclear fission in a nuclear reactor, and it is also used for cancer screening based on the released positron (positron). It can be imaged by the positron tomography (PET) used.
First, Cs-127 was generated by irradiating sodium iodine with a helium ion beam accelerated at high speed by a cyclotron.However, the amount of Cs-127 produced here is very small, and it is necessary to remove 2 million times the amount of sodium ions and the like existing in the vicinity in order to use it as a tracer.For this purpose, we succeeded in separating and purifying the Cs-127 tracer using a graft polymerizing material that selectively collects cesium.
When the obtained Cs-127 tracer was administered to a living rat and imaged by PET, the taken-up cesium accumulated in organs such as the kidney and small intestine through the bloodstream, and then gradually moved out of each organ. rice field.In this way, visualization of the movement of cesium in living animals was realized for the first time in the world.
Using the technology developed this time, the amount of cesium in each organ can be observed in real time after ingestion, which is expected to be useful for evaluation research of internal exposure dose.In addition, it is expected to contribute to the development of radioactive cesium reduction technology for agricultural products by applying it to plant research.
Paper information:[Scientific Reports] Non-invasive imaging of radiocesium dynamics in a living animal using a positron-emitting 127Cs tracer
