4b. The Dangers of Radioactive Emissions - beware of ionising radiations from radio-isotopes!

The penetration trends and the effects of Ionisation from radioisotopes

All radioactive emissions are extremely dangerous to living organisms. When alpha, beta or gamma radioactive emissions hit living cells they cause ionisation (ionization) effects, they can kill cells directly or cause genetic damage eg to the DNA molecules. High radiation doses cause burn effects and can kill cells. However, low doses don't kill the cells, but if they are genetically damaged and can still replicate, these mutations can lead to the formation of cancerous cells and tumor development later. When alpha, beta and gamma radiation collide with neutral atoms or molecules they knock off electrons and convert them into charged or ionised particles (ions). Positive ions are formed on electron loss and negative ions are formed by electron gain. The positive ions maybe unstable and very reactive and cause other chemical changes in the cell molecules. The 3 radiations have different capacities to cause cell damage.

• If the radioactive source, a 'radionuclide', gets inside the body the 'danger' order is alpha > beta > gamma.  The bigger the mass or charge of the particle, the bigger its ionising impact on atoms or molecule. BECAUSE the order of mass is 4 > ¹/₁₈₅₀ > 0, and for electric charge the order is 2+ > -1 > 0.  If the radioisotope is in the body the radiation impacts directly on cells with the consequences described above.
• However, if the radioactive source is outside the body, the order danger is reversed to gamma > beta > alpha because the danger order follows the pattern of penetrating power. The smaller the mass and charge the more penetrating the radiation (reverse the order of above). Gamma and beta are the most penetrating and will reach vital organs in the body and be absorbed.  Most gamma passes through soft tissue but some is inevitably absorbed by cells.  Alpha radiation would not penetrate clothing and is highly unlikely to reach living cells.
• Because of the dangers of this ionising or atomic radiation, all workers and medical staff who are likely to be near radioactive or ionising sources must wear lapel radiation badges containing photographic film to monitor their exposure to radiation. The film is regularly developed and the darker the film the more radiation would have impacted on the person. 
• Examples of precautions that can be taken include:
  • Radiographers wear lead lined aprons and anyone else involved in radiotherapy cancer treatment must take particular precautions and radiation monitored.
  • In nuclear fuel preparation and reprocessing, as much work is done using robotic control systems in behind steel, concrete, lead or thick lead glass panels for visual monitoring of the situation.
  • In research laboratories, experiments are conducted in sealed fume cupboards at the laboratory side and technicians work through sealed whole arm gloves through a thick lead glass front. You can also reduce the pressure in the fume cupboard so there is no chance of pressure leakage out into the laboratory area.
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