A New System for Three-dimensional Clinostat Synchronized X-irradiation with a High-speed Shutter for Space Radiation Research

Abstract

Considering further human activity in space, it is necessary to study the biological effects of combined microgravity and space radiation; however, many aspects of these combined effects remain unclear. In the field of space biology, it is difficult to investigate relative biological effectiveness (RBE) and combined effects because the ability to conduct and replicate space experiments is restricted. Therefore, a new three-dimensional (3D) clinostat synchronized X-irradiation system with a high-speed shutter was fabricated following the development of a heavy-ion irradiation system. This study showed that the system could simultaneously irradiate rotating samples using the 3D clinostat, with the samples in a horizontal position. The samples were completely irradiated because of the flatness and symmetry of the irradiation fields. Doses were virtually identical under both standing and rotation conditions, with the difference being <1% under the assumption of X-irradiation at a dose of 1 Gy. Our new device could accurately synchronize X-irradiation and simulated microgravity at the ground level. The device is expected to greatly contribute to space radiation research as a valuable platform for studies concerning RBE and the combined effects of radiation under microgravity. ©2016 Jpn. Soc. Biol. Sci.

Simultaneous Exposure of Cultured Human Lymphoblastic Cells to Simulated Microgravity and Radiation Increases Chromosome Aberrations

“…The X:Y ratios of clinorotation were set at 11:13 rpm and = 66°/s:78°/s, to accurately synchronize irradiation when the samples were in a horizontal position. For the control, cells in the chamber were mounted on a stationary clinostat to achieve static condition (1 G ), with the same pulse irradiation [ 17 , 18 , 29 , 30 ]. The dose rate was approximately 0.03 Gy/min for both X-ray and C-ion irradiation under the simulated μ G or 1 G conditions.…”

“…However, for the experiments of this type, it was often necessary to stop clinostat rotation in order to irradiate cells. Recently, we have developed a ground-based system for irradiating cells while they are under simulated μ G using a three-dimensional (3D) clinostat [ 17 , 18 ] as a new system for ground-based space environment studies. This system allows the irradiating of cells without stopping the rotation of the clinostat, hence it is truly simultaneous exposure.…”

Space Radiation Biology for “Living in Space”

“…However, there are two major limitations associated with this approach: (i) it is necessary to stop rotation during irradiation as the sample was exposed to radiation outside the incubator after or before rotation with a RWV [183][184][185][186][187][188] and (ii) nonuniformity of dose flatness in the irradiation area occurs because of chronical irradiation of a rotating sample with a RPM [189,190]. To address these problems, we have developed a system of simultaneous irradiation in simulated-μG (SSS) using 3D clinostat [191,192]. Our SSS is based on technologies related to X-ray irradiation with a high-speed shutter [191] and Cion radiotherapy such as accelerator systems and respiratory gating systems [192].…”

“…To address these problems, we have developed a system of simultaneous irradiation in simulated-μG (SSS) using 3D clinostat [191,192]. Our SSS is based on technologies related to X-ray irradiation with a high-speed shutter [191] and Cion radiotherapy such as accelerator systems and respiratory gating systems [192].…”

Role of High-Linear Energy Transfer Radiobiology in Space Radiation Exposure Risks

“…To allow the assessment and management of human health risks in space, it is necessary to obtain more basic data on the combined effects of radiation under microgravity [30,65]. To address these serious problems, we developed 3-dimensional clinostat-synchronized heavy-ion and x-ray irradiation systems [66,67], which are expected to provide significant contributions to space radiation research, as a valuable platform for studies on the relative biological effectiveness and the combined effects of radiation under microgravity.…”