Comparison of dicentric dose response curves of 6MV LINAC X-rays and 60Co γ-rays for biodosimetry application

• Published in: Applied radiation and isotopes 2017-11, Vol.129, p.124-129
• Main Authors: Kumar, A. Arul Anantha, Bakkiam, D., Sonwani, Swetha, Seenisamy, R., Sivasubramanian, K., Venkatraman, B.
• Format: Article
• Language: English
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2017.08.020

In vitro Dicentric (DC) dose response curves of 6MV X-rays (3Gy/min) and 60Co γ-rays (0.63Gy/min) were generated and compared (intra-laboratory) to understand their similarities and differences. Human peripheral blood samples exposed to ten different doses (0, 0.05, 0.1, 0.25, 0.5, 1, 2, 3, 4 and 5Gy) of 6MV X-rays and 60Co γ-rays were subjected to Dicentric Chromosome Assay (DCA) and dicentrics, excess acentric fragments (AF) and chromatid breaks (CB) were scored. Totally about 31,553 metaphase spreads were scored for the purpose. Dose response curves of both radiation qualities were almost same except for a 13.8% higher β value for 6MV X-rays. However, blind tests results revealed that both these curves are biologically equivalent and exhibited good dose prediction accuracy for the entire dose range. This demonstrated the feasibility of interchangeable use of these curves in biodosimetry. Consequently it has been suggested that LINAC facilities worldwide can be roped in for biodosimetry capacity augmentation towards managing nuclear emergency situations involving γ-radiation exposures. •This is the first study on the comparison of dicentric dose response curves of 6MV X-rays (3Gy/min) and 60Co γ-rays (0.63Gy/min) pertaining to biodosimetry application.•Both DC dose response curves were almost similar except for a 13.8% higher β value for 6MV X-rays due to dose rate effect.•Six dose blinded samples exposed to three different doses of 6MV X-rays and 60Co γ-rays were used to validate DC curves.•Demonstrated the feasibility of interchangeable use of 6MV X-rays and 60Co γ-rays DC curves in biodosimetry.