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How this can be dangerous
How we can protect ourselves
- Types will be discussed later
- In some cases will need both conversion table and unit analysis
- Lights on work examples
(1) 12 ft to _ m
(2) 25 mi/hr to _ ft/sec
(3) 22 Ci to _ Bq
(4) Ex. 7
(5) 35 GBq to _ Ci ( w/out table)
The cosmic radiation which strikes the earth induces radioactivity in the atmosphere in the same way that the TRIUMF accelerators induce radioactivity in their shielding. Most of this radioactivity is very short-lived. Some radionuclides however survive to eventually reach the surface of the earth. Among these are H (tritium), Be (beryllium-7) and C (carbon-14) which has the longest half-life (5730 years). The concentration of these radionuclides in the air is quite low and they are all radioactive species with low radio-toxicity. As a result the average dose equivalent from this source is small: only approximately 0.01 mSv per year.
0-150 Perhaps increased cancer with long latency\150-400 increased cancer risk---400-800 GI damage at higher rates
A gamma particle is a photon. It is produced as a step in a radioactive decay chain when a massive nucleus produced by fission relaxes from the excited state in which it first formed towards its lowest energy or ground-state configuration.
With the microbeam, it is possible to expose individual cells and using the modern cellular and molecular techniques to study the changes that occur in the cell that is "hit" by the radiation and in neighboring cells that were not directly traversed by the radiation. It is possible to demonstrate that the "hit" cell communicates with its neighboring cells and triggers cellular and molecular changes in these cells. Bystander effects have been demonstrated in vitro using a number of different cell culture systems and a wide range of biological endpoints. It is critical to determine if this response increases or decreases the risk for production of late occurring disease. This is an area of current research and vigorous discussion. For the bystander effect to be of significance in terms of risk assessment it is important to determine if these effects are produced in vivo using experimental animals.