41Ca – a possible neutron specific biomarker in tooth enamel

A. WALLNER; A. ARAZI; T. FAESTERMANN; K. KNIE; G. KORSCHINEK; H. MAIER,; N. NAKAMURA; W. RÜHM; G. RUGEL

NUCLEAR INSTRUMENTS AND METHODS IN PHYSICS RESEARCH B - BEAM INTERACTIONS WITH MATERIALS AND ATOMS

Elsevier

Año: 2004 vol. 223 p. 759 - 764

0168-583X

The measurement of long-lived radionuclides, produced by neutrons originating from the atomic-bomb explosions, offers the possibility to reconstruct neutron fluences to which survivors in Hiroshima and Nagasaki were exposed. The long-lived radionuclide, 41Ca (T1=2 ¼ 103000 years), is suggested here as a means for a retrospective determination of thermal neutron fluences, directly within the human body of a survivor. As proper material tooth enamel is proposed. The 41Ca signal in tooth enamel may be correlated with the exposure to A-bomb induced thermal neutron fluences, provided the natural background level of 41Ca/Ca is significantly lower. Therefore, tooth samples of unexposed survivors of the A-bomb explosions have been examined by means of accelerator mass spectrometry, in order to quantify the natural background level of 41Ca/Ca. Measured 41Ca/Ca ratios were confirmed to be as low as about 2 · 10^15. Thus, the A-bomb induced additional signal should be detectable for survivors at  epidemiological relevant distances. Since tooth enamel had already been used as a dosemeter for gamma radiation from the A-bomb explosion, the detection of 41Ca in tooth enamel would allow, for the first time, an assessment of both, c-ray and neutron exposures in the samebiological material.