Physics' of Nuclear Medicine 2

Question 1

2 types of Exposure to Radiation

Answer 1

1.) NATURAL ENVIRONMENTAL RADIATION
2.) MAN-MADE RADIATION

Question 2

Three types of natural Environment Radiation

Answer 2

Cosmic Ray - particulate and electromagnetic radiation emitted by the sun
and the stars.

Terrestial Radiation - results from deposits of uranium, thorium and other
radionuclides in the earth.

Internally Deposited Radionuclides - mainly potassium-40 are natural metabolites, they have always been with us and contribute an equal dose to each of us.

Question 3

RADIOACTIVE DISINTEGRATION

Answer 3

The process by which the nucleus
spontaneously emits particles and energy and transforms itself into another atom to reach stability.

Question 4

RADIOACTIVITY

Answer 4

It is spontaneous emission of particles (alpha,
beta) or radiation (gamma, k capture) when an unstable nuclide transform into stable nuclide; Radioactivity never reaches zerobecause of physics half life (T½ p).

Question 5

RADIOACTIVE DECAY

Answer 5

A naturally occurring process whereby an
unstable atomic nucleus relieves its instability through the emission of one or more energetic particles.

Question 6

Biological Half Life (T ½ b)

Answer 6

the time required for the body or organ to reduce by 50% of the administered dosage for any radioactive substance by regular process of elimination

Question 7

Effective Half Life (T ½ eff)

Answer 7

is the time required for body or organ to eliminate 50% of the administered dosage of radioactive material by combined process of radioactive decay and biologic
elimination; Effective Half Life is always shorter than the shorter of Tp and Tb.

Question 8

2 Type of Radioactivity

Answer 8

NATURAL ACTIVITY – the substance already has
radioactivity in the natural state.

ARTIFICIAL ACTIVITY – the radioactivity has been
induced by radiation.