Characterization of a novel plastic scintillation detector for in vivo electron dosimetry

Abstract

Introduction: Real-time dosimetry of surface doses in electron beams has not been widely established yet. Plastic scintillation detectors (PSD) promise high spatial resolution and real-time dosimetry with minimum perturbation of the radiation field. This study characterizes a novel PSD in an electron beam to determine its suitability for in vivo dosimetry. Methods: Dual-channel Cherenkov radiation correction and dosimetric characterization of the PSD were investigated using reference ionization chambers. Percentage depth-dose curves, lateral profiles, and output factors were compared with reference ionization chamber measurements. Surface doses were measured on solid water and on an anthropomorphic phantom and were compared to ionization chamber and radiochromic film measurements. Results: The investigated PSD demonstrated clinically acceptable linearity, dose rate independence, isotropy and reproducibility (total variation <2%). Dosimetric deviation in R50 and R80 were below 1.0 mm and lateral profiles agreed with a mean absolute error below 1.5%. Small field measurements were within 2% of the reference ionization chamber results. Surface dose measurements had mean relative deviations of 1.3% from ionization chamber measurements and 2.1% from radiochromic film measurements. Conclusion: The PSD investigated in this study is suitable for clinically acceptable electron beam dosimetry and provides accurate dosimetric results for surface dose measurements. It has the potential to be used for real-time in vivo dosimetry.