Fractionated Radiation & Dose Rate Effect

Question 1

Lethal Damage

Answer 1

Leads to Cell Death

Irreversible

Irreparable

Question 2

Sublethal Damage

Answer 2

Can be repaired in hours unless additional damage added

Second dose interacts

Evident by increased survival with fractionated doses

Question 3

Dose Rate Effect for Photons

Answer 3

Dose rate determines biological impact

Reducing dose rates generally reduces damage

Question 4

Inverse-Dose Rate Effect

Answer 4

At a small range of optimal low dose rates, cells are able to progress to G2 phase where they are more sensitive, therefore enhancing cell killing at a lower dose rate.

Question 5

Brachytherapy and Enocurietherapy

Answer 5

Implanting sources directly into the body

Question 6

Intracavity Irradiation

Answer 6

Source is placed in body cavity near the tumor

Question 7

Interstitial Irradiation

Answer 7

Source of radioactive seeds are placed in the tumor