PROBLEM TO BE SOLVED: To provide a radiation monitor that is miniaturized and less in invasiveness, reduces impacts of radiation induction light generating in an optical fiber, and makes it possible to conduct real-time dosimetry in a body.SOLUTION: A radiation monitor 1 is composed of: a radiation emission unit 10 that generates light of intensity relying upon incident radiation dose; an optical fiber 20 that transmits a photon generated in the radiation emission unit 10; a photoelectric converter 30 that sends out a piece of electric pulse with respect to a piece of the transmitted photo; an irradiation timing detection device 80 that measures light emission from an optical fiber 20 including a radiation induction light, and detects an irradiation timing of radiation; a dose computation device 40 that counts the electric pulse amplified by the photoelectric converter 30, and converts a counting value of the measured electric pulse into a dose of the radiation; and a display device 50 and the like.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2020,JPO&INPIT【課題】小型で侵襲性が小さく、光ファイバ内で発生する放射線誘起光の影響を低減し、体内でのリアルタイムな線量測定を可能とする。【解決手段】放射線モニタ1は、入射した放射線量に依存した強度の光を発生する放射線発光部10、放射線発光部10で発生したフォトンを伝送する光ファイバ20、伝送されたフォトン1個に対して1個の電気パルスを発信する光電変換器30、放射線誘起光を含む光ファイバ20からの発光を計測し放射線の照射タイミングを検知する照射タイミング検知装置80、光電変換器30で増幅された電気パルスを計数し、計測した電気パルスの計数値を放射線の線量に換算する線量演算装置40および表示装置50等から構成される。【選択図】 図1