L 4: Interaction of Ionizing radiation

Question 1

Photodisintegration

Answer 1

• It is Interaction of energetic photon with the nucleus results in emission of atomic neutron.
• It does not contribute considerably to attenuation in a atient.
• It becomes more efficient in high Z materials of the treatment head.
• It can cause single event pacemaker dysfunction.
• Hence >10MV beams are not used to treat patients with a pacemaker

Question 2

Gamma Decay

Answer 2

A and Z stays the same
Occurs in pico seconds

Question 3

Naturally occuring Isotopes

Answer 3

C-14
U-288
K-40
Th-232
Ra-226

Question 4

Alpha Decay

Answer 4

• Changes both atomic mass and atomic number of the molecule, both A & Z

Question 5

Beta + Decay

Answer 5

• Electron capture
• Atomic number decreases by 1

Question 6

Beta -ve Decay

Answer 6

• Increases Atomic number by 1