Page 192 - Pharmaceutics IV (02-06-01305)

spontaneously convert (decay) to the stable present isotopes alpha
beta or gamma rays.

1-Alpha Radiation
It is a result of excess energy dissipation by unstable nuclei

in the form of alpha particles .It has 2 positive charges(2 protons)&2
neutrons & total mass of 4 units, identically with Helium nucleus, it
attracts electrons & becomes a helium atom.

e.g. polonium 210 Po decaying to 206 Po .

Superscript before the element’s symbol represents the atomic mass
& after the element represent’s the atomic number.

Alpha particles ,being heavy, are ejected at about 1/10 th
the speed of light .They can travel about 1-4 inches in the air.

2-Beta Radiation

It is produced through beta decay of unstable nuclei & follow either
of : electron emission ,positron emission ,&electron capture.

It may be either electrons with negative charge ,Negatrons, or
positive electrons ,positrons .These 2 particles ,β- & β+ ,have a range
of more than 100 feet in air & up to about 1mmin tissue . Beta
particle are not destructive as alpha particles .It possesses a lot of
kinetic energy

.Beta particles is slower process compared with alpha or gamma
decay ,most of beta are emitted at the speed of light .

3-- Gamma Rays : are most penetrating electromagnetic radiation of
shortest wave length & highest energy ,just below the x-ray region of
the electromagnetic spectrum.

2