Article Research and Development of SPICE-NIRS microbeam

Konishi, Teruaki  ,  Kobayashi, Alisa  ,  Oikawa, Masakazu  ,  Furusawa, Yoshiya

Microbeams made it possible to deliver a defined number of charged particles on a single cell with a resolution of a few micrometers, and are most advantageous for the studies of biological response on low dose radiation. Our microbeam irradiation system, the SPICE-NIRS microbeam provides a 3.4 MeV proton microbeam focused with a quadrupole magnetic lens on an upward vertical beam line. In the previous fiscal year, 2014, we made several major advancements in the SPICE operation system. We re-developed our operation system with 64bit OS platform and installed PCI-Express (PCIe) SSD board (RevoDrive3x2 240GB PCI-Express) which has potentials to read and write data with 1000 MB/secs and it is approximately 100 folds faster compared to ordinary HDD. These developments made SPICE capable of targeting cells with 1/5 of time for image capturing and image analysis.In this FY2015, we conducted several developments on the optical configuration of ON and OFF-line microscope system to full fill the advantageous features of high throughput imaging system that were accomplished by the previous year. The optical configuration between the camera and the optical lens was designed to be 40 mm closer than the previous design (Figure 1A). From this modification, due to the light decreased path from the light source to optical lens, and the focused plane, exposure time of the camera was reduced to 1/2 ~ 1/5 depending on the selected fluorescent wavelength.In addition, we redesigned our X-Y axis voice coiled motorized (VCM) stage of OFF-line microscope system (Figure 1B, C). Currently VCM stage installed on the ON-LINE microscope system made possible to irradiate 400 cells per minute, which is still the fastest in Japan. However, the small stroke distance of 8 mm, which limited the number cells to be targeted and it applications in radiobiology. To overcome the limitations, newly designed VCM stage can be controlled with longer distance of 26 mm stroke with 40 nm resolution. In case of irradiation, it was estimated that the stage enables cell irradiation to be 300 cells per minutes, which is slightly slower compared to the currently installed VCM stage of the ON-line microscopic system. It is under optimization for higher speed control and to be installed on ON-LINE microscope. Currently, SPICE can target mammalian cells from single ion with stability and high throughput using an upward vertical beam of below 2-micrometer in diameter [1]. A variety of irradiation modes have been established for radiation-induced bystander effects, cytoplasmic irradiation, etc. Within these several years, we have focused on the radio-induced bystander effects, especially on the aspect on the damaging and protective bystander response and signaling between two different kinds of cells, such as 1) human lung cancer and normal cells, and 2) cancer stem-like cells, CSCs and non stem-like cancer cells, NSCCs in human fibro-sarcoma HT1080 cells. SPICE was successful in contributing in the studies of radiobiology and radio-oncology. [2- 5]Over 90 days of beam time were provided to SPICE microbeam proposals without any cancellations due to the machines. Many researchers from oversea have visited our SPICE-NIRS microbeam and we diligently worked on providing DEMO beam times to researchers with an interest in radiological studies using microbeam techniques.

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