Hall 9 - Medical Countermeasures to RT Exposure

Question 1

What are prophylactic agents given prior to radiation exposure to reduce the level of damage?

Answer 1

Radioprotectors

Question 2

What part of radioprotectors scavenges free radicals?

Answer 2

Sulfahydryl (SH) group
»donates a hydrogen atom to directly repair sites of DNA damage

Question 3

What is the dose reduction factor?

Answer 3

DRF = dose of RT with a drug / dose of RT without a drug
(to produce the same biological effect)

*Maximum DRF = OER

Question 4

How is amifostine used as a radioprotector?

Answer 4

Prodrug
Alkaline phosphatase removes a phosphate to expose SH group for free radical scavenging

Question 5

What is the dose limiting toxicity of amifostine?

Answer 5

Hypotension
Must be given IV (short half life, no BBB penetration)

Question 6

What are drugs given after radiation exposure but before symptom onset?

Answer 6

Radiation mitigators
Ex) G-CSF, GM-CSF

Question 7

What are drugs that help remove ingested radioactive compounds?

Answer 7

Radionuclide eliminators
Ex) Potassium iodide, Prussian blue capsules, DTPA