Carbon 14 useful radioactive dating not nuclear medicine
However, the main radioisotopes such as Tc-99m cannot effectively be produced without reactors.* Radioisotopes are an essential part of medical diagnostic procedures.
However scientists tested the hypothesis that solar radiation might affect the rate at which radioactive elements decay and found no detectable effect.Recently, however, researchers at Purdue University observed a small (a fraction of a percent), transitory deviation in radioactive decay at the time of a huge solar flare.Data from laboratories in New York and Germany also have shown similarly tiny deviations over the course of a year.This has led some to suggest that Earth's distance from the sun, which varies during the year and affects the planet's exposure to solar neutrinos, might be related to these anomalies.Researchers from NIST and Purdue tested this by comparing radioactive gold-198 in two shapes, spheres and thin foils, with the same mass and activity. The team reasoned that if neutrinos are affecting the decay rate, the atoms in the spheres should decay more slowly than the atoms in the foil because the neutrinos emitted by the atoms in the spheres would have a greater chance of interacting with their neighboring atoms.In developed countries (26% of world population) the frequency of diagnostic nuclear medicine is 1.9% per year, and the frequency of therapy with radioisotopes is about one-tenth of this.
In the USA there are over 20 million nuclear medicine procedures per year, and in Europe about 10 million.
The unswerving regularity of this decay allows scientists to determine the age of extremely old organic materials -- such as remains of Paleolithic campfires -- with a fair degree of precision.
The decay of uranium-238, which has a half-life of nearly 4.5 billion years, enabled geologists to determine the age of the Earth.
The maximum neutrino flux in the sample in their experiments was several times greater than the flux of neutrinos from the sun.
The researchers followed the gamma-ray emission rate of each source for several weeks and found no difference between the decay rate of the spheres and the corresponding foils.
In developed countries (a quarter of the world population) about one person in 50 uses diagnostic nuclear medicine each year, and the frequency of therapy with radioisotopes is about one-tenth of this.