Basic research for development of compact wireless capsule type dosimeter

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09063
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Medical Physics and Radiological Technology
• Research Institution: Nagoya University
• Principal Investigator: Koyama Shuji 名古屋大学, 脳とこころの研究センター, 准教授 (20242878)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 半導体検出器 / 無線 / 線量計 / フォトダイオード / 電流電圧変換 / 太陽電池

Outline of Final Research Achievements

A small-sized X-ray dosimeter needs a detector element whose sensitivity has the smallest directional dependence of sensitivity. In this study, the spherical solar cell element and the detector in which the photodiode element was adhered back to back and the periphery was polished were compared, and the latter was found to be suitable. The linearity of the output of this detector, the dose rate dependence of the sensitivity, and the energy dependence of the sensitivity were investigated, and good characteristics were obtained. A dosimeter unit was constructed by connecting this detector to a small wireless analog/digital converter via a small current/voltage conversion circuit. When using this unit, X-rays were incident on the dosimeter unit itself, but this effect was extremely small. It was thought that the electronic circuit could be further miniaturized and encapsulated.

Free Research Field

放射線計測工学

Academic Significance and Societal Importance of the Research Achievements

医療被ばくの評価においては，実際に測定できない人体の代わりに人体の形を模したファントムと呼ばれるものに，線量計素子を埋め込んで測定したりする．現在，使用されている小型線量計素子は，Ｘ線照射の後，何らかの読取り装置を用いて積算された線量値を得るものが一般的である．本研究で開発した線量計により，被ばくの様子をリアルタイムで計測することが可能となり，より詳細な解析が可能となる．また，さらに小型化できれば，カプセル内視鏡のように，実際の人体内での測定も可能となると考えられる．