| Accident scenario |
| On 5 February 1989, a radiation accident occurred at the DELMED gamma ray facility located in Sam Salvador, El Salvador, in which three men received large exposures to unshielded 60-Co gamma radiation emitted from an source. During routine operations of a gamma ray facility used for sterilising plastic products for medical use, an unshielded 666 T Bq 60-Co (18,000 Ci) source became lodged in the ‘up position’ and did not return to the protective pool of water under it. Three operators at the facility bypassed the safety interlock system, entered the sterilisation unit and attempted to disengage the source and correct the malfunction．At one metre from the stacked wayer 60-Co source the dose rate of the l.2 MeV gamma radiation was subsequently determined to be 0.26 C/kg/min (1000 R/min). Based on preliminary reconstructions of the accident scenario，it was estimated that the men may have been exposed for perhaps three to four minutes at various distances from the source，and that they may have received doses in the range of 3to 10 Gy with the localised exposures in excess of 200 Gy to the feet of Patient A and S. |
| Early clinical findings |
| Initially, the men were evaluated at a local clinic. As their medical conditions worsened, the decision was made in late February 1989 to transfer them to the Hospital Angeles del Pedregal in Mexico City. Upon admission, Patient A was severely ill with haemopoietic and gastrointestinal findings typical of the acute radiation Syndrome. He exhibited extensive radiodermatitis, with radiation burns of his legs and feet and oedema of both hands. He was severely malnourished, having lost 10 kg body weight. Patient B was malnourished and presented findings consistent with haemopoietic and gastrointestinal syndromes. He had incurred severe radiation burns on his legs and feet. Patient C showed less severe burns to his left foot. All three men presented severe pancytopenia and bone marrow aplasia. Recombinant human granulocyte macrophage colony stimulating factor (rHuGM-CSF) (Scheramex, SACV, Mexico DF) was started in two-hour IV infusions in a daily dose of 240 microgram/sq-m until each patient's total neutrophil count had reached 1,500. The time intervals required for neutrophil recovery were 20 d for Patient A, 10 d for Patient B, and 9 d for Patient C after the start of the rHuGM-CSF. At this time there was no recovery in platelet or haemoglobin values that were in fact transfusion dependent. In response to requests for assistance from the International Atomic Energy Agency (IAEA), Vienna, Austria, and the Pan American Health Organization (PAHO), members of the Radiation Emergency Assistance Centerrrraining Site (REACrrS) staff travelled to Mexico City to provide medical consultation and expertise in dosimetry reconstruction. |
| Chromosomal dosimetry |
| On 11 March, 7 June, and 27 June,
1989, (i.e. 35, 123, and 143 days post-exposure) heparinised venous blood
samples were collected from the three men, and the blood was transported
to the REAC/TS Cytogenetics Laboratory in chilled styrofoam containers.
Transit time en route to Oak Ridge was approximately 26 hours, where lymphocyte
cultures were initiated. Qdr method and contaminated-Poisson methods were
applied for dose estimation. |
| References |
| Littlefield LG, Joiner EE, Colyer
SP, Ricks RC, Lushbaugh CC, and Hurtado-Monroy R: The 1989 San Salvador
60-Co radiation accident: Cytogenetic dosimetry and follow-up evaluations
in three accident victims. Radiat. Protect. Dosimet., 35: 115-123, 1991. |
| Chromosome aberration analysis |
