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Supplementary explanatory material 1. Outline and history The Japan Atomic Energy Agency (hereinafter referred to as JAEA) has been striving to develop a tool (see Figure 1) to be used with the cooling pipes attached to major structures inside the International Thermonuclear Experimental Reactor (ITER). This tool can access the cooling pipes (internal diameter: 100 mm) from the inner side, follow bends, and weld, cut, and inspect branch pipes (internal diameter: 50 mm). For these welding and cutting tools to access inside the pipe and carry out inspection and repair at any desired location, power for such processing must be transferred to the target site. Confirmation work before and after welding and cutting as well as during processing is also necessary. Since the process of welding and cutting is done on the inner surface of the pipes, however, visually inspecting the work is extremely difficult. Thus, to observe the status of the welding and cutting processes, as well as before and after processing inside the pipe, which is a small, limited space, the JAEA has developed the composite-type optical fiber system shown in Figure 2. This system makes possible the process of welding, cutting, and observation using a multi-functional optical fiber and lens optics system, while enabling parallel transmission of the observation images and a 1 kW YAG laser beam. This composite-type optical fiber was thought to be applicable to processes other than remote maintenance of ITER, and application in diverse fields is being studied. At present, a project is currently under way, in collaboration with multiple companies and universities, using the patent of this composite-type optical fiber, to develop minimally-invasive-type laser measuring and treatment equipment in the field of life sciences.   2. Current result To apply the developed composite-type optical fiber in the field of life sciences, the JAEA cooperated with the National Center for Child Health and Development in the development of a laser clamp-type endoscope for use in fetal surgical treatment, as shown in Figure 3. Known as a Tainai-LaMiel, the device may be used with fetuses and placentas with hereditary abnormalities. In developing this device, we bundled illumination lights around the composite-type optical fibers to minimize the size of the lens at the tip of the optical fiber (outer diameter: approximately Ø1 mm). It was also confirmed that the lens could be used without being damaged, even at a laser output of 40 W.  In the case of twin-to-twin transfusion syndrome (TTTS) such as that shown in Figure 4, treatment is relatively easy if the placenta is attached on the back side of the mother's body. However, treatment is sometimes difficult if the placenta is attached on the abdominal side. Use of the newly-developed Tainai-LaMiel shown in Figure 5 allows the laser to be irradiated with ease even if the placenta is attached on the abdominal side. Moreover, if laser light is to be irradiated using a Tainai-LaMiel, as shown in Figure 6, the laser irradiation can reach the target site accurately and without fail because laser irradiation is integrated with visual observation. Because of this, even better therapeutic effects can be expected.    A variety of functions will now be added, including the expansion of the range of visual field through measurement of blood flow in targeted blood vessels and image processing. Animal experiments are also planned to be performed first at the National Center for Child Health and Development, and the device's clinical application will subsequently be studied. |
