Introduction: The purpose of this study was the development of a quality assurance(QA)tool that enabled us to measure the dose distribution of an electron beam with a plastic scintillator.We compared the brightness distribution of the scintillator for electron beams with the percentage depth dose(PDD)and the off-center ratio(OCR).Methods: A plastic scintillator plate placed in a water tank parallel to the beam axis was irradiated with a high-energy electron beam of 6,9,12,and 15 MeV.The scintillation light by the irradiation was recorded with a CCD camera.We analyzed the brightness distributions and compared these with PDD and OCR,as measured with a diode detector.We subtracted Cherenkov light images,captured by irradiating water without the scintillator,from the scintillation images to suppress the background.Results/Discussion: The brightness of the scintillation light was proportional to the dose of the electron beam(2-200 cGy)and was independent of the dosage rate(200-800 MU/min).The differences between depth brightness distributions and the PDD were a maximum of 5%in the build-up region for the electron beam.However,subtraction of the Cherenkov light from the scintillation images improved these underestimations.The depth brightness distributions after the subtraction were in agreement with the PDD within ±2%for the 6,9,and 12 MeV beams and within ±3%for the 15 MeV beam.The lateral brightness distributions at the depth of the 90%,70%,and 50%dose were in agreement with the OCR within(夕)5%.The full width at half maximum(FWHM)measured with the scintillator agreed within ±2 mm with those obtained with the diode for the electron beams.Conclusion: We showed the potential of the QA tool with the scintillator to measure PDD and OCR accurately from the brightness distribution of the scintillator.