Diagnostic Range Ionizing Radiation and Reactive Oxygen Species Production: an Initial Experience

Life Sciences-Radiology for better medical diagnosis

Abstract

Radiation is a common  occurrence in our daily lives that comes from both natural and man-made sources.  Ionizing Radiation (IR) causes damage either directly or indirectly through  the generation of reactive oxygen species (ROS). Oxidative damage to  DNA, lipids, proteins, and many metabolites occurs  through  a complex series of processes  that  are  enhanced  by endogenous  signalling which is activated by free radicals. Though literature is abundant on ROS and antioxidants at high doses, no  study to  the  best  of our  knowledge has assessed  the  ROS levels after Multi Detector Computed Tomography  (MDCT) examination (i.e.  in  diagnostic range  radiation). The  aim  of the  present   study  was to  assess  the  production of ROS after diagnostic level radiation by MDCT examination and at 24 hour follow up. The study involved fifty patients posted  for clinically indicated MDCT which were recruited.  The average radiation dose was 2-9 mGy. Three  blood samples were drawn, one prior to CT (control sample), within half an hour of CT (post CT) and 24 hrs after CT. 3 ml venous blood was withdrawn in aseptic conditions  and  immediately  serum  was  isolated  for  ROS  assessment.  The  blood  examination  results  were  compared   in immediate  and  post  24  hour  after  MDCT  and  both  were  compared   with  control  values  and  correlated  with  radiation parameters. Our  results  have shown a significant increase in ROS level in immediate post  CT samples compared  to prior CT scan samples (control) (p value <0.0001). The ROS levels reduced  at 24 hours compared  to immediate post CT, however  they were  still higher than  control values.  Our  findings  reflect that  there  is a rapid  increase in free radicals production in the mitochondria after diagnostic level radiation. Detection of higher ROS levels at 24 hours  suggests incomplete repair with the presence  of some residual oxidative species at 24 hours.