Title of article :
An in-vivo study on the energy dependence of X-ray biological effectiveness
Author/Authors :
Fadel, M.A Department of Biophysics - Faculty of Science - Cairo University, Giza, Egypt , Bakr, R.H Ionizing Radiation Metrology Lab - National Institute for Standards, Tersa St. El-Haram, Giza, Egypt , El-Sersy, A.R Ionizing Radiation Metrology Lab - National Institute for Standards, Tersa St. El-Haram, Giza, Egypt
Abstract :
Background: The International Commission on Radiological Protection (ICRP) has
attributed the same relative risk for X and gamma radiations of all energies. Several
studies have proven that the biological effect of low energy photon is more than
that of higher ones. The assessment of risks is important due to the wide use of low
energy X-rays for mammography screening and other diagnostic applications.
Materials and Methods: Five X-ray beam qualities characteristics according to ISO
-4037 and consultative committee of ionizing radiation (CCRI) were studied in
details. In pilot study made to investigate the minimum dose that cause measurable
biological effects, one hundred male albino rats were equally divided into five
groups namely A, B, C, D and E. Group A was used as control while animals of other
groups were whole body exposed to different radiation doses from 137Cs γ-rays.
For studying the biological effect energy dependency, eighty male albino rats were
equally divided into 8 groups namely F, G, H, I, J, K, L and M. Group F was used as
control and was not exposed to any type of radiation while animals of other groups
were whole body exposed to the same dose of radiation but at different dose rates
and different energies. Blood samples were collected and serum samples were
separated for further biochemical investigations. Biochemical investigations for
blood sera included alanine aminotransferase (SGPT), aspartate aminotransferase
(SGOT), blood urea nitrogen (BUN), creatinine (CREA), calcium (Ca++) and Creatine
phosphokinase (CPK) level. Results: The results showed remarkable variation of
the measured biochemical parameters levels with different photon energies
that reflect the energy dependency of the investigated parameters.
Conclusion: It’s clear from the data that the same absorbed dose delivered
to the exposed animals induces different effect according to the used photon
energy. Low energy X-rays were found to be more biologically effective than
higher ones.
Keywords :
Energy dependent , Biological effect , X-ray beam qualities
