2020 年 9 巻 1 号 p. 1-6
In this paper, 2 types of particle beam cancer therapy were focused and a comparative analysis of the legitimation strategy of each diffusion process based on the theory of Social Shaping of Technology (SST) was conducted. As a result of analysis, an interdependent process of technology development - evaluation system - popularization, as defined in SST, the proton particle beam technology which is inferior to heavy particle beam technology in both efficacy and cost-effectiveness of the treatment acquired the validity almost equivalent to the heavy particle beam technology and spread in Japan. The heavy particle beam technology has diffused to foreign countries with the legitimacy to acquire foreign currencies by the policy of different agents, that is government cabinet. Both technologies can be regarded as similar technologies, but their diffusion processes have been different. In general, new medical technologies gain legitimacy and diffuse under established evaluation systems, and competing technologies are eliminated. This paper shows that it is not necessarily eliminated from the market only by the technical effectiveness superiority of object presence, and that both technologies diffused to the market by multifunctional interaction with various legitimations.