Numerical signal treatment for optimized alanine/ESR dosimetry in the therapy-level dose range.
Electron spin resonance (ESR) spectra of alanine detectors irradiated to absorbed doses below 5 Gy are affected by a varying non-linear background which mainly influences the lower limit of detection in alanine/ESR dosimetry. A mathematical method based on fast Fourier transform is described capable of filtering simultaneously background and noise in the frequency domain of ESR spectra. It provides clearer alanine/ESR signals down to 50 mGy. Even in non-irradiated but long-term stored alanine detectors an ESR signal could be observed similar to irradiated alanine (pre-signal). A linear ESR signal vs absorbed dose relationship was found above 200 mGy, after correction for background and pre-signal. The number of repeated ESR read-out cycles and hence the time required for a precise and reliable low-dose evaluation have significantly been reduced. The method has been worked out for the therapy-level dosimetry range and tested on a Bruker ESP 300 and for comparison Bruker EMS 104 ESR spectrometer.
Ruckerbauer
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F
GSF-Forschungszentrum für Umwelt und Gesundheit, Institut für Strahlenschutz, Oberschleissheim, Germany.
Sprunck
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M
Regulla
D F
DF
D000409:Alanine / Q000737:chemistry / Q000528:radiation effects*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods* / Q000706:statistics & numerical data; D005583:Fourier Analysis; D005609:Free Radicals / Q000032:analysis; D006801:Humans; D011874:Radiometry / Q000379:methods* / Q000706:statistics & numerical data; D011879:Radiotherapy Dosage; D012815:Signal Processing, Computer-Assisted; D012984:Software
D005609:Free Radicals; D000409:Alanine