A Case Report: Cytogenetic Dosimetry after Accidental Radiation Exposure during (192)Ir Industrial Radiography...

Area of Science:

• Medical Physics
• Radiation Biology
• Occupational Health

Background:

• Accidental overexposure of an industrial radiography worker involving an Iridium-192 source.
• Initial dose assessment via thermoluminescent dosimeter indicated 0.078 Sv.
• Absence of clinical symptoms post-incident.

Purpose of the Study:

• To perform biological dosimetry to clarify radiation dose uncertainties for the exposed worker.
• To assess radiation protection aspects following accidental gamma exposure.
• To investigate potential partial-body exposure scenarios.

Main Methods:

• Cytogenetic examination of blood lymphocytes, including dicentric chromosome and micronucleus analysis.
• Comparison of observed frequencies with laboratory control values for unexposed individuals.
• Dose estimation using dicentric analysis and calibration curves for Cobalt-60 gamma radiation.
• Application of the Dolphin method to assess heterogeneous (partial-body) exposure.

Main Results:

• Micronucleus frequency remained within the normal background range.
• Dicentric chromosome frequency (0.003/cell) was significantly elevated compared to the background (0.0007/cell).
• Dicentric analysis estimated a mean dose of 0.066 Gy, with a 95% upper confidence level of 0.181 Gy.
• Overdispersion of dicentric chromosomes suggested heterogeneous exposure, estimated at 2.1 Sv to 21% of body volume via the Dolphin method.

Conclusions:

• A radiation overexposure of the industrial radiography worker is confirmed.
• The findings suggest a potential partial-body exposure scenario.
• Cytogenetic analysis is crucial for validating dose assessments in occupational radiation incidents.