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  • One non-radiation worker showed deterministic effects
  • Two did not, but did receive some dose
  • Five other workers were tested but did not show any effect


Three workers were carrying out gammagraphy using a 3.33 TBq Ir-192 source on the 22.5 metre high platform of a tower. The pigtail was disengaged (or was never engaged) from the driver, one of the workers unscrewed the guide tube and the source fell on the platform. The workers left and the following day (11 PM), Worker A found the source and tried to identify it. Worker A showed the source to Worker B, who noticed that Worker A had a swollen cheek.

Worker A handed the source to Worker B, who went down the tower with the source in his hand. Both workers decided to hand the source to their supervisor and when they were in his office, the personal dosimeter of a worker from another company started indicating the high radiation field.  The source was identified as a dangerous radioactive source and the workers were advised to put it away. The source was put in a container and the owner company was contacted to recover the source. The time elapsed from direct contact with the source to the recovery was about half an hour.

The three construction workers were sent for medical examination, including a cytogenetics examination, and were interned in the hospital. One worker showed some deterministic effects, the other two do not show any effect. Five workers from the gammagraphy company were sent for cytogenetics examination, none of them showed any deterministic effect.

INES procedure (click the highlighted flowchart items to follow the procedure)

Figure 4, page 145 of the Manual

Figure 5, page 146 of the Manual

Determine rating based on doses to individuals

Check the answer


One non-radiation worker showed deterministic effects.

Level 3 defines that there should be:
"The occurrence or likely occurrence of a non-lethal deterministic effect"

The radiography source that became detached would be rated at Level 3.