IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
HIGH SENSITIVE RADIATION DETECTOR FOR RADIOLOGY DOSIMETRY
Autor/es:
MAURO VALENTE; FRANCISCO MALANO; WLADIMIR MOLINA
Lugar:
Cusco
Reunión:
Congreso; 14th INTERNATIONAL SYMPOSIUM OF SOLID STATE DOSIMETRY; 2014
Institución organizadora:
Soc. Peruana de Proteccion Radiologica
Resumen:
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Fricke solution has a wide range
of applications as radiation detector and dosimetry. It is
particularly appreciated in terms of relevant comparative advantages,
like tissue-equivalence when prepared in aqueous media like gel
matrix, continuous mapping capability, dose rate recorded and
incident direction independence as well as linear dose response. This
work presents the development and characterization of a novel Fricke
gel system, based on modified chemical compositions making possible
its application in clinical radiology. Properties of standard Fricke
gel dosimeter for high dose levels are used as starting point and
suitable chemical modifications are introduced and carefully
investigated in order to attain high resolution for low dose ranges,
like those corresponding to radiology interventions. The developed
Fricke gel radiation dosimeter system achieves the expected typical
dose-dependency, actually showing linear response in the dose range
from 20 up to 4000 mGy. Systematic investigations including several
chemical compositions are carried out in order to obtain a good
enough dosimeter response for low dose levels. A suitable composition
among those studied is selected as a good candidate for low dose
level radiation dosimetry consisting on a modified Fricke solution
fixed to a gel matrix containing benzoic acid along with sulfuric
acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade
water. Dosimeter samples are prepared in standard vials for its
in-phantom irradiation and further characterization by
spectrophotometry measuring visible light transmission and absorbance
before and after irradiation. Samples are irradiated by typical kV
X-ray tubes and calibrated Farmer type ionization chamber is used as
reference to measure dose rates inside phantoms in at vials
locations. Once sensitive material composition is already optimized,
dose-response curves show significant improvement regarding overall
sensitivity for low dose levels. According to the obtained results,
it is found that the proposed method shows satisfactory reliability
and good enough performance for a promising radiation dosimetric
system.