Gamma-Ray Imaging

Gamma ray is an energetic form of electromagnetic radiation produced by radioactivity or nuclear or subatomic processes such as electron-positron annihilation and radioactive decay.

Gamma ray is discovered by French chemist and physicist, Paul Ulrich Villard in 1900 while studying the radiation emanating from Radium, Polonium and Uranium. He finds that gamma-ray can not be deflected by magnetic fields.

Special features of the Gamma radiation

• The shortest wave length
• The highest frequency
• The most energy
• Type of a radiation
• Can come from the natural resources such as radon gas, radioactive elements in the earth etc.
• This is a packet of energy (photons) that have no charge or mass (weight)

Domains which are used Gamma radiation imaging

Hospitals

1. Radiotherapy

High intensity gamma radiation will kill cells. It is used in a technique called radiotherapy to treat cancer by treating the cancer cells with a beam of radiation and then rotating source of the beam.

figure 1: Gamma Radiation as cancer treatment 

2. Gamma Camera

Gamma Camera Equipment is a tool used in nuclear medical depiction, to see and analyze or diagnose overview of the human body by detecting the radiation beam from a radio isotope that is inserted into the patient's body.

3. Imaging tests

Certain types of imaging tests such as CT scan and   nuclear medicine tests(such as PET scans and bones   scans) expose people to low levels of radiation in order to create internal pictures of the body.(Some imaging tests such as MRI and ultrasound do not expose people to ionizing radiation).

Space experiments

1. Fermi Gamma-ray Space Telescope.

This animation tracks several gamma rays through space and time, from their emission in the jet of a distant blazer to their arrival in Fermi's Large Area Telescope (LAT).

2. Astronomical Observations.
A star in the constellation of Cygnus exploded about 15,000 years ago. It generated a super heated stationary gas cloud known as the Cygnus Loop. That glows in a spectacular array of colours and the Cygnus Loop imaged in the gamma-ray band.

Airports

1. Airport security scanners

In recent years some airports have begun to use whole body scanners as a way to detect object hidden by clothing. These scanners are different from the metal detector most people are familiar with. The types of body scanners currently in use is based on millimeter wave technology. Neither millimeter wave scanners nor metal detector expose people to Gama rays.

Ports

1. Cargo Container Scanning

Gamma-ray scanners inspect cargo containers to detect weapons and other contraband as part of integrated programme to increase the security of containerized cargo entering the U.S from around the world.

figure 2: Cargo container scanning with gamma-ray

Food and Nutrition

1. Food Irradiation

Some foods particularly poultry and produce are exposed to radiation as a mean of killing bacteria and other harmful food-borne pathogens. This is called cold-pasteurization and it reduces the incidence of food poisoning and spoilage.

Other Industrial Uses

Gamma rays are used by Engineers, since they can penetrate the concrete better than X-rays.

• Can be used to look for cracks in pipes and aircraft parts.
• Can be used for checking the health of the steel structure supporting the over bridges. 

Contributed by

Team Pixels

S.P Wijesekara

S.A Weerasekara

W.M.D.L Wijekoon

Triarch Group

K.T.D Perera

E.M.K.L Edirisinghe

H.M.M Wimalaweera

Unicornz

M.A.P.S Dushmantha

W.G.C.W.K Kulathungha

R.P.G.L.S Gunarathna

Glitter
I.D.T Maddumage
H.M.K Gunarathne
W.W.L.S.T Wanigasinghe

Group Meister
R.C.U De Zoysa
S.D Munagoda
E.M.R Tharanga