JCO Tokai-mura Criticality Accident (30 September 1999)
Accident scenario:           see ¤JCO-Victims 

Reference 

     Kanda, R., Minamihisamatsu, M. and Hayata, I. (2002): Dynamic analysis of chromosome aberrations in three victims of the Tokai-mura criticality accident. Int. J. Radiat. Biol., 78:857-862. 
Chromosome aberration analysis 
[1] G2 PCC rings
Case Sampling No. of Distibution of PCC rings
ID time cells 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A 9 h 100 21 31 30 14 3 1
23 h 100 23 30 28 14 5
48 h 15 2 7 4 1 1
B 9 h 100 52 26 19 1 1 1
23 h 100 44 41 13 2
48 h 100 39 49 9 3
C 9 h 100 77 22 1
23 h 100 80 17 3
48 h 100 83 12 4 1
3.5 mo 100 85 13 2
6.5 mo 200 177 20 3
14 mo 250 231 19
[2] Dicentrics (see also □ JCO-ABC)
Case Sampling No. of Distibution of dicentrics
ID time cells 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A 9 h 50 1 1 1 4 4 7 5 3 10 3 2 6 2 1
23 h 20 2 4 3 4 2 2 2 1
48 h 8 1 2 1 2 1 1
B 9 h 75 10 6 26 15 6 7 2 1 2
23 h 50 6 6 10 15 10 2 1
48 h 50 3 5 14 10 7 7 1 3
C 9 h 200 114 66 16 3 1
23 h 200 117 61 17 4 1
48 h 200 114 64 17 4 1
[3] Rings
Case Sampling No. of 2
ID time cells 0 6 2 3 4 5 6 7 8 9 10 11 12 13 14 15
A 9 h 50 6 7 15 11 7 4
23 h 20 1 1 8 6 2 2
48 h 8 1 4 3
B 9 h 75 42 22 10 1
23 h 50 33 10 6 1
48 h 50 32 10 7 1
C 9 h 200 165 28 6 1
23 h 200 172 26 2
48 h 200 176 20 4
.
 

Dose assessment by the use of G2 PCC rings (arrows)

     The doses were estimated by direct inferranceof PCC ring frequencies and the dose response relationship obtained for 200 kVp X-rays. (Photo: by courtesy of Dr. I. Hayata, NIRS).

Methodology: see:
     Kanda, R., Hayata, I. and Lloyd D. D. (1999): Easy biodosimetry for high-dose radiation exposure using drug-induced, prematurely condensed chrosomes. Int. J. Radiat. Biol., 75:441-446.

Suggested empirical formula for calibration:
      Y=1.451E-01X-5.155E-03X2+8.567E-05X3-6.747E-07X4+2.033E-09X5 (0<X<50 Gy)
     (Commentary by M. S. Sasaki in compilation)