J Korean Soc Ther Radiol.  1989 Jun;7(1):85-92.

High Energy Electron Dosimetry by Alanine/ESR Spectroscopy

• Chu SS

Abstract

Dosimetry based on electron spin resonance(ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to l Gy. In a water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies (6~21 MeV) and therapeutic dose levels(1~60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by 2~ 5% than those calculated by nominal energy CE factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator.

Keyword

Electron spin resonance(ESR); Alanine dosimeter; Absorbed dose; Free radical dosimetry(FRD); Electron beam

MeSH Terms

Alanine
Amino Acids
Free Radicals
Particle Accelerators
Spectrum Analysis*
Water
Alanine
Amino Acids
Free Radicals
Water