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
5. Types of 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.
Lower energy electromagnetic waves.
Not enough energy to pull electron from orbit, but can excite the
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
Too much exposure may cause harm. Eg. UV radiations can cause
skin cancer.11/13/2016 6
7. Application of ionizing radiation
Medical Applications and Radiotracers
8. Food Sterilization
Gamma irradiation of foods
often from 60Co source
Spices, herbs and dehydrated
vegetables. Also pork and
poultry are also preserved in
FDA approved11/13/2016 8
9. Medical Applications of Radioactivity
can be introduced into
laboratory reactions or
organisms and traced
Renograms employ the
use of tracers.
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.
11. Medical Applications of Radioactivity
Infrared gun or Temperature
Used for quick body
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-
Magnetic Resonance Imaging (MRI – Nuclear
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
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.
16. Radiotherapy methods
provides a highly localized dose by one of two
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
17. Radiation not only kills cells, it can also kill germs or
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
Criminal investigators use
radiation to examine
Museums rely on radioactive
materials to verify authenticity
of art objects and paintings
20. Smoke Detectors
Americium-241 emits alpha particles and ionizes air in a space in the
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
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
25. Disadvantages Of Excessive Exposure To Radiations.
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
There are 3 main uses of ionising radiation in medicine:
treatment, diagnosis and sterilisation.
Radiotherapy is used to treat cancers by irradiating them with
Radioactive tracers are used to diagnose and investigate several
Ionising radiation is used to sterilise medical equipment as it kills
germs and/or bacteria.