Advances in Targeted Microbeam Irradiation Methods for Live Caenorhabditis elegans Charged-particle microbeam irradiation devices, which can convert heavy-ion or proton beams into microbeams and irradiate individual animal cells and tissues, have been developed and used for bioirradiation in Japan, the United States, China, and France. Microbeam irradiation technology has been used to analyze the effects of irradiation on mammalian cancer cells, especially bystander effects. In 2006, individual-level microbeam irradiation of the nematode Caenorhabditis elegans was first realized using JAEA-Takasaki's (now QST-TIAQS's) TIARA collimated microbeam irradiation device. As of 2023, microbeam irradiation of C. elegans has been achieved at five sites worldwide (one in Japan, one in the United States, one in China, and two in France). This paper summarizes the global progress in the field of microbeam biology using C. elegans, while focusing on issues unique to microbeam irradiation of live C. elegans, such as the method of immobilizing C. elegans for microbeam experiments.

Simple Summary: The nematode Caenorhabditis elegans, which is only 1 mm long, is used as a model to study the effects of irradiation on tissues (organs) of living organisms. This paper reviews the development of irradiation techniques using charged-particle microbeams in Japan, the U.S., China, and France, in which heavy-ion and proton beams (types of ionizing radiation) are targeted to specific cells or regions of C. elegans, and outlines the progress made over the past 20 years and where we are today. An essential part of irradiating the targeted cell/tissue of microscopic animals is having an immobilization method which does not damage the animals' physiological activity. This article introduces some technical difficulties that differ from those concerning the irradiation of cultured cells, which have been the main target of irradiation in the past. Charged-particle microbeam irradiation devices, which can convert heavy-ion or proton beams into microbeams and irradiate individual animal cells and tissues, have been developed and used for bioirradiation in Japan, the United States, China, and France. Microbeam irradiation technology has been used to analyze the effects of irradiation on mammalian cancer cells, especially bystander effects. In 2006, individual-level microbeam irradiation of the nematode Caenorhabditis elegans was first realized using JAEA-Takasaki's (now QST-TIAQS's) TIARA collimated microbeam irradiation device. As of 2023, microbeam irradiation of C. elegans has been achieved at five sites worldwide (one in Japan, one in the United States, one in China, and two in France). This paper summarizes the global progress in the field of microbeam biology using C. elegans, while focusing on issues unique to microbeam irradiation of live C. elegans, such as the method of immobilizing C. elegans for microbeam experiments. [ABSTRACT FROM AUTHOR]