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Bone analysis shows radiation exposure twice deadly altitude



The bombing of Hiroshima and Nagasaki in 1945, the only use of nuclear weapons in the history of warfare, still causes the rest of humanity to shudder. Several thousand civilians died after being bathed by the detonation of "Little Boy" and "Fat Man" over the two cities.

The explosions prompted scientists around the world to conduct detailed studies and gain insights into the radiation and its effects. The work continues, but only recently has a group of scientists in Brazil made a major breakthrough and discovered that a person standing over Hiroshima one kilometer from the epicenter of the bomb radiates twice as much radioactivity to a human body [1

9659002] Scientists studied the jaw bones of a victim and used features of paramagnetism or the situation in which bones become weakly magnetic due to the influence of x-rays and gamma rays. The phenomenon, first discovered by Sergio Mascarenhas, one of the authors of the work, served as a marker, allowing the researcher to date archaeological fossils by obtaining a rough estimate of the radiation they absorbed.  169137_web Brazilian Researchers described the first retrospective dosimetric study using electron spin resonance spectroscopy using human jaw bone from an atomic attack victim Photo: Sergio Mascarenhas (IFSC-USP)

Mascaren has shown that Phenomenon that was seen in the bone of the unidentified victim, it was good enough to get a dosimetric signal, but the exact estimate was found when modern data analysis tools and a technique called electron spin resonance spectroscopy were put into use.

As part of this method The researchers moved backwards to measure the exact amount of radiation exposure. They removed tiny parts of the jawbone and irradiated them to reach the original level of radiation in the bone.

"We added radiation to the material and measured the rise in the dosimetric signal," co-author Oswaldo Baffa said in a statement. "We then constructed a curve and extrapolated the starting dose when the signal was probably zero, and using this calibration method we were able to measure different samples because each bone and part of the same bone has a different sensitivity to radiation, depending on its composition."

Findings from the study revealed that the bone in question had been exposed to a hefty 9.46 Gray (Gy) or Joule radiant energy per kilogram. "About half of this dose or 5 Gy is fatal if the whole body is exposed to it," Baffa explained. The researchers further added that the value obtained with their technique is comparable to that of non-biological samples from the bomb site.

The group believes that this technique could be useful in determining who was exposed to nuclear particles and in need of treatment. "There were serious doubts about the feasibility of using this method of determining the radiation dose deposited in these samples because of the processes involved in the episode," said Angela Kinoshita, another author of the work, in the statement. "The results confirm their feasibility and open up various possibilities for future research that could clarify details of the nuclear attack."

The study titled "Electron Spin Resonance (ESR) Dosage Measurement in the Bone of Hiroshima A Bomb Victims," ​​was published on April 27 in the journal PLOS One.


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