Triphasic Dose-Response of Hematological Parameters in Healthcare Workers Exposed to Ionizing Radiations

Abstract

Objectives: To investigate the impact of chronic and low-dose ionizing radiation (IR) exposure on the workers’ hematopoietic system. Methods: Hematological parameters in IR exposed healthcare workers (n. 180) were compared to those determined in unexposed controls (n. 180). The relationship with the 5-year cumulative doses: 1.28 mSv, was assessed. Results: Red blood cells (RBCs), hemoglobin (HB) and hematocrit (HCT) showed significant differences compared to controls. A non-linear relationship was determined with respect to the cumulative doses. RBCs showed a significant decrease at the first 1.28 mSv highest one. Conclusions: IR exposure affected the hematopoietic system according to an hormetic phenomenon, intended as a biphasic dose-response with a low-dose stimulation and a high-dose inhibition, and, potentially, through a triphasic dose-response. These results deserve attention to define/implement suitable IR occupational risk assessment and management strategies.