Radiation dosimetry of an accidental overexposure using EPR spectrometry and imaging of human bone

On 11 December 1991 a radiation accident occurred at an industrial accelerator facility. A description of the facility and details of the accident are reported in Schauer et al., 1993a). In brief, during maintenance on the lower window pressure plate of a 3 MV potential drop accelerator, an operator placed his hands, head, and feet in the radiation beam. The filament voltage of the electron source was turned ‘off’, but the full accelerating potential was on the high voltage terminal. The operatorʹs body, especially his extremities and head, were exposed to electron dark current. At approx. 3 months post-irradiation, the four digits of the victimʹs right hand and most of the four digits of his left hand were amputated. Electron paramagnetic resonance (EPR) spectrometry was used to estimate the radiation dose to the victimʹs extremities. Extremity dose estimates ranged from 55.0 Gy (± 4.7 Gy) to 108 Gy (± 24.1 Gy).