Doped plastic scintillator properties for soft tissue dosimetry

Abstract

In medical dosimetry, the radiation quantity of interest is frequently the dose to tissue. To make direct dosimeters that show the dose absorbed in soft tissue, tissue-equivalent material is preferred. Plastic scintillators (PLS) are made of materials with a density similar to soft tissue and relatively have energy independent response. Non-proportionality must be taken into account when reproducing the light output spectrum for photons below 200 keV, as it reduces light output significantly. In comparison to a standard plastic scintillator, both low and high energy photons’ pulse height distribution spectra as a result of lead doping were measured and calculated. The effect of a 0.5 % lead doping scintillator is sufficient to make up for the loss or difference between soft tissues and plastic scintillators in response to low energy photons, particularly below 200 keV.