Fluoroscopic procedures, carries the risk of exposure of cardiac catheterization staff to ionizing radiation. We measured endothelial circulating progenitor cells (CD34, CD133 and KDR) in blood of cardiac catheterization staff and in patients undergoing fluroscopic procedures befor and after rediotherapy. Results showed that in the latter the numbers of circulating progenitor cells had increased and accordingly there was an increased capacity for tissue repair in patients after cardiac catheterization procedures. Aso among cardiac catheterization staff and among Industrial radioraphers there is an increase in circulating progenitor cells compared to controls.This regenerative process is decreased by smoking as evidenced by increased levels of Stromal Derived Growth Factor (SDF-1) and decreased numbers of EPCs among smokers compared to controls. These studies were accompanied by the frquency of micronucleus assay and chromosomal aberrrations
Nerve growth Factor, CD 45, nestin and acidic glial fibrilar acid protein, which are markers of neural regeneration were found to be significantly higher among cardiac catheterization staff and among Industrial radioraphers implying that as ionizing radiation induces an recognized damage at low doses it also initiates regenerative process.
Such progenitor cells generated for repair of damage induced by ionizing radiation can be theselves cause of ionizing radiation induced carcinogenesis