60Co Accident, Shandon Jining, China, 21 October 2004

Accident scenario
     On 21 October 2004, a radiation accident occurred in Shandon Jining, China. While using 60Co to irradiate vegetables for refreshing processing in a irradiation fabrication plant, two workers (A and B) entered the irradiation room misguidedly because of damage to safety interlock indicating lamp of the radiation source, and severely exposed to gamma-rays. The activity of the 60Co source at the time of accident was 1.42×1015 Bq. 
Early clinical symptoms 

     Three min after exposure, worker A felt scorching on his face, stomach-ache and weakness, and developed nausea, vomiting. Ten min after exposure, worker B suffered from headache, stomach-ache and started to vomiting.

     Two hours later, Both workers were sent to local hospital. Worker A had the symptom of lethargy, dysphoria, flash on face and two hands, pressing pain of parotid and abdomen. Temperature was 39.4 oC. Worker B had diarrhea, congested overlowing on his head and neck. Temperature was 38 oC.

     Both workers were transferred to Hospital in Beijing 55 hour after the accident. Absolute number of lymphocyte counts were 0.1×109/L and 0.117×109/L in worker A and B, respectively. The blood samples were obtained from the workers for chromosome aberration analysis.

. Cellularity in bone marrow at 3 days after the accident
Subject Neutrophilic stab cells Neutrophilic Neutrophilic Polychromatic Orthochromatic Lymphocytes Monocytes Plasma cells Reticular cells
and segmented cells myelocytes metamyelocytes normoblasts normoblasts
A 95.0 % 0 0 0 0.5 % 2.5 % 0 1.0 % 1.0 %
B 85.5 % 2.5 % 2.5 % 0.5 % 0 0 0.5 % 1.5 % 0 .

     Both workers received peripheral blood stem cells transplantation, but worker A died 33 days after the accident and worker B died 75 days after. 

Reference 

     Yao, B., Jiang, R., Ai, H. S., Li, Y. F., Liu, G. X. and Qiu, L. J. (2010): Biological dose estimation for two severely exposed patients in a radiation accident in Shandon Jining, China, in 2004. Int. J. Radiat. Biol., 86:800-808. 

Chromosome aberration analysis 
.
Subject Sex Age No. of No. of Distribution of dicentrics (Dic) + centric rings (Rc)
(yrs) cells Dics+Rc 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
A M 37 14 137 1 2 1 2 3 2 1 1 1
B M 41 100 467 2 6 8 14 20 17 14 7 5 4 3
.
Subject Sex Age No. of No. of Distribution of MN
(yrs) CB cells MN 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
B M 41 100 242 5 22 28 22 17 5 1
.

Commentary at data compilation

      The dose-distribution profiles by unfolding Dic+Rc distribution. The dose distribution profiles and equivalent whole body dose (EWBD) in right panel are not adjusted by lymphocyte survival (For the method, see Sasaki MS, Int. J. Radiat. Biol., 79:83-97, 2003). Incidentally, the authors estimated 20.0 Gy and 8.8 Gy for worker A and B, respecively, by infering to their in vitro dose response curves.
      The commentary given here is the one added at the time of data compilation, and does not necessarily reflect the conclusion of the authors.