TY - JOUR
T1 - Organic scintillators with long luminescent lifetimes for radiotherapy dosimetry
AU - Beierholm, Anders Ravnsborg
AU - Lindvold, Lars René
AU - Andersen, Claus Erik
PY - 2011
Y1 - 2011
N2 - Organic scintillators with long luminescent lifetimes can theoretically be used to temporally filter out radiation-induced luminescence and Cerenkov light (the so-called stem signal) when used as fibre-coupled radiotherapy dosimeters. Since the medical linear accelerators (linacs1) used for radiotherapy treatments deliver pulsed beams, the stem signal can be suppressed using dosimeter materials with luminescent lifetimes much longer than that of the stem signal. However, producing organic scintillators with long luminescent lifetimes has proven difficult in practice. We report on the results of experiments performed using two organic scintillators, one commercially available and one custom made. The luminescent lifetimes of the scintillators have been measured using i) optical excitation by pulsed UV light, and ii) irradiative excitation using high-energy X-rays from a linac. A luminescent lifetime component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long enough for practical applications in radiotherapy dosimetry, this study supports that the stem signal can be greatly reduced by applying a temporal gating.
AB - Organic scintillators with long luminescent lifetimes can theoretically be used to temporally filter out radiation-induced luminescence and Cerenkov light (the so-called stem signal) when used as fibre-coupled radiotherapy dosimeters. Since the medical linear accelerators (linacs1) used for radiotherapy treatments deliver pulsed beams, the stem signal can be suppressed using dosimeter materials with luminescent lifetimes much longer than that of the stem signal. However, producing organic scintillators with long luminescent lifetimes has proven difficult in practice. We report on the results of experiments performed using two organic scintillators, one commercially available and one custom made. The luminescent lifetimes of the scintillators have been measured using i) optical excitation by pulsed UV light, and ii) irradiative excitation using high-energy X-rays from a linac. A luminescent lifetime component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long enough for practical applications in radiotherapy dosimetry, this study supports that the stem signal can be greatly reduced by applying a temporal gating.
KW - Radiation physics
KW - Strålingsfysik
U2 - 10.1016/j.radmeas.2011.04.016
DO - 10.1016/j.radmeas.2011.04.016
M3 - Journal article
SN - 1350-4487
VL - 46
SP - 1982
EP - 1984
JO - Radiation Measurements
JF - Radiation Measurements
IS - 12
ER -