2. OBJECTIVE(S)
• To learn about some importance of radiation to humans.
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3. What Is Radiation
 The process in which energy is
released in the form of waves or
particles from an unstable atom.
 Naturally occurring and man-made
 ...most are produced in nuclear
reactors or particle accelerators
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5. Types of Radiation
Ionizing radiation
Higher energy electromagnetic waves (gamma) or heavy particles
(beta and alpha).
High enough energy to pull electron from orbit.
Gamma rays, X-Rays, Neutrons are examples.
Non-ionizing radiation
Lower energy electromagnetic waves.
Not enough energy to pull electron from orbit, but can excite the
electron.
 Eg. Visible or infrared light, microwaves and radio waves.

6. Importance of Non-ionizing radiation
 Microwave ovens to heat food.
 Toasters use infrared to toast or burn.
 We watch television, talk on cell phones, and listen to the radio
through the use of radio waves.
 Visible light used in laser pointers.
 Ultra violet (UV) radiation for pasteurizing fruit juices and preserving
some foods.
NOTE:
Too much exposure may cause harm. Eg. UV radiations can cause
skin cancer.11/13/2016 6

7. Application of ionizing radiation
Food Sterilization
Medical Applications and Radiotracers
Smoke detectors
Radiocarbon Dating
Energy Production
Weapons
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8. Food Sterilization
 Gamma irradiation of foods
often from 60Co source
 Spices, herbs and dehydrated
vegetables. Also pork and
poultry are also preserved in
this way
 FDA approved11/13/2016 8

9. Medical Applications of Radioactivity
 Radioactive nuclides
can be introduced into
laboratory reactions or
organisms and traced
for diagnostic
purposes.
 Renograms employ the
use of tracers.
Radiotracers

10. Radiotracers - Choice of Tracer
 Gamma rays are chosen since alpha and beta particles would be absorbed by
tissues and not be detected outside the body.
 Technitium-99m is most widely used because it has a half-life of 6 hours.
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11. Medical Applications of Radioactivity
 Infrared gun or Temperature
gun.
Used for quick body
temperature measurements
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12. Medical Applications of Radioactivity - Scanners
 Medical Scanners utilize many types of radiations
X-Rays – Bone structures opaque to rays
X-ray computed tomography (CT Scan – X-
rays)
Magnetic Resonance Imaging (MRI – Nuclear
magnetism)
Ultrasound (high frequency sound waves)
√ Positron Emission Tomography (PET Scan)

13. Medical Applications of Radioactivity - Scanners
 X-ray scans to detect injury or the
presence of foreign objects in patients
 CT scans to create a computer-
generated 3D image of cross-sections of
the body

14. Medical Applications of Radioactivity - Radiotherapy
Radiation is also used in radiotherapy where higher doses of radiation
are used to kill cancerous cells during the treatment of tumours.
The aim of radiation therapy is to cause damage to the cancerous
cells whilst minimising the risk to surrounding healthy tissue.
The damage inflicted by radiation therapy causes the cancerous cells
to stop reproducing and thus the tumour shrinks.
The amount of radiation given to the patient has to be accurately
calculated so that the damage is limited to the cancerous cells only.
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15. Radiotherapy methods
TELETHERAPY
 involves irradiating tumours
using beams of high-energy
radiation, focused
specifically on the tumour to
minimize damage to
surrounding tissue
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16. Radiotherapy methods
BRACHYTHERAPY
 provides a highly localized dose by one of two
methods:
either the insertion of sealed radioactive
sources in the form of rods, wires or through
hollow tubes into or close to the tumour, or
the swallowing by the patient of a radioactive
liquid that is selectively absorbed by the
tumour.
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17.  Radiation not only kills cells, it can also kill germs or
bacteria.
 Nowadays, medical instruments (e.g. syringes) are prepacked
and then irradiation using an intense gamma ray source.
 This kills any germs or bacteria but does not damage the
syringe, nor make it radioactive.

18. Scientific Research
Archaeologists use 14C to date
artifacts containing plant or
animal material
 Criminal investigators use
radiation to examine
evidence
 Museums rely on radioactive
materials to verify authenticity
of art objects and paintings

19. FLUOROSCOPY FOR
SECURITY SCANS
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20. Smoke Detectors
 Americium-241 emits alpha particles and ionizes air in a space in the
detector
 Ions allow a current to flow
 Smoke absorbs alpha particles, interferes with ion formation and
electric current. An alarm sounds

21. Agricultural Uses
 Radioactive materials pinpoint where illnesses strike animals
to breed disease-resistant livestock
 Nutritional value, baking and melting
qualities of some crops and cooking times have
been improved using isotopes
 Hardier and more disease resistant crops (peanuts,
tomatoes, onions, rice, soybeans, barley) have been
developed using radioactive materials in agricultural
research

22. Agricultural Uses
 Isotopes help farmers and scientists
control pests; e.g., California has
used radiation sterilization since
the mid-70s to control Mediterranean
fruit fly infestations
 Radioactive materials show how plants
absorb fertilizer; this helps researchers
figure where and how much to apply to
crops for maximum yield

23. Generation Of Electricity
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US nuclear
power plants
provide 20%
of electricity

24. Production Of Nuclear Weapons
 caghj
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25. Disadvantages Of Excessive Exposure To Radiations.
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 The damaged caused by exposure to radiation is determined by the ;
Type of radiation
The duration of exposure
The part of the body exposed
 The effects of radiation are either prompt or delayed

26. Diadvantanges Of Excessive Exposure To Radiations.
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29. Summary
 There are 3 main uses of ionising radiation in medicine:
treatment, diagnosis and sterilisation.
 Radiotherapy is used to treat cancers by irradiating them with
ionising radiation.
 Radioactive tracers are used to diagnose and investigate several
medical conditions.
 Ionising radiation is used to sterilise medical equipment as it kills
germs and/or bacteria.

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31. References
 Uses of radioactive substances.
http://www.radiation.org 19th October, 2016
 Tim, Newman (2016). X-ray exposure: How Safe Are X-rays?
http://www.medicalnewstoday.com/articles 19th October, 2016
 Health effects of radiation. http://en.Wikipedia.org/wiki/health/ 19th
October, 2016
 World nuclear association (2012). Radiation and life.
http://www.world-nuclear.org/information-library/safety-and-
security/
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