Abstract:
:The energy dependence of alanine/EPR dosimetry, in terms of absorbed dose-to-water for clinical 6, 10, 25 MV x-rays and 60Co gamma-rays was investigated by measurements and Monte Carlo (MC) calculations. The dose rates were traceable to the NRC primary standard for absorbed dose, a sealed water calorimetry. The electron paramagnetic resonance (EPR) spectra of irradiated pellets were measured using a Bruker EMX 081 EPR spectrometer. The DOSRZnrc Monte Carlo code of the EGSnrc system was used to simulate the experimental conditions with BEAM code calculated input spectra of x-rays and gamma-rays. Within the experimental uncertainty of 0.5%, the alanine EPR response to absorbed dose-to-water for x-rays was not dependent on beam quality from 6 MV to 25 MV, but on average, it was about 0.6% lower than its response to 60Co gamma-rays. Combining experimental data with Monte Carlo calculations, it is found that the alanine/EPR response per unit absorbed dose-to-alanine is the same for clinical x-rays and 60Co gamma-rays within the uncertainty of 0.6%. Monte Carlo simulations showed that neither the presence of PMMA holder nor varying the dosimeter thickness between 1 mm and 5 mm has significant effect of the energy dependence of alanine/EPR dosimetry within the calculation uncertainty of 0.3%.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Zeng GG,McEwen MR,Rogers DW,Klassen NVdoi
10.1088/0031-9155/49/2/006subject
Has Abstractpub_date
2004-01-21 00:00:00pages
257-70issue
2eissn
0031-9155issn
1361-6560journal_volume
49pub_type
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