Exam 1.5: Radiation Biology, Safety, Infection Control Flashcards
What are the three effects of radiation on atoms and molecules
Excitation
Ionization
Breakage of Molecular Bonds
What happens to an electron when it is excited by an xray photon?
It vibrates before returning to its normal state, releasing the energy stored from the impact as heat or light
How could radiation create an ion pair?
A high energy photon can impact an atom and eject an orbital electron creating a positive ion and a free electron….an ion pair
Why is molecular bond breakage the worst type of radiation damage?
It renders the molecules useless and can kill the organelle, which might lead to cell death
What free radicals are created via radiolysis of water?
OH* and Hesi
Can then react with water to form
HO2
H2O2
Besides water, what other common biological molecules can be turned into free radicals when hit with radiation
CO2
NO2
O2
What is a DIRECT effect of radiation exposure?
Ionization energy is placed directly into critical molecules within the cell
What is the critical biomolecule?
DNA
What is the INDIRECT effect of radiation exposure?
The water in the cell is radiolysed creating free radicals and toxic chemicals (H2O2) that then damage critical molecules like DNA and proteins
What is the period between the radiation exposure and the damage incurred by indirect effects?
Latent period
What are some health problems caused by the accumulative effects of radiation exposure?
Cancer
Cataracts
Birth defects
What factors of the radiation influence the radiobiological effects of radiation exposure?
Type of Radiation LET (Linear Energy Transfer) Total Dose Penetrating ability/Quality of Beam Local area v. Entire body
How do Alpha particles and X-rays compare in terms of LET?
Alpha particles have a High LET
X rays have a low LET
What host factors influence the radiobiological effects of radiation exposure
Species Intrinsic resistance Type of Tissue Rate of cell division Somatic Tissue vs. Genetic Tissues
What are the worst tissue cells to get hit with radiation?
Reproductive
Bone Marrow
GI Mucosa
What are the “best” tissue cells to get hit with radiation?
Muscle
Nerves
What are 4 Deterministic Effects
Erythema and Skin Ulcers
Epilation (Hair falls out by the roots)
Cataract Formation
Sterility
What is the term for genetic effects of radiation
Stochastic effects
What are the 4 Total Body Irradiation Syndromes
CNS Syndrome
GI Syndrome
Bone Marrow Syndrome
Lethal Effects
Which syndrome requires a threshold of 50+ Grays?
CNS (Neurons are able to take a lot of radiation)
What syndrome is imparted with 10-50 Grays
GI Syndrome
No cases of survival with doses of 10+ Grays
How much radiation is required to acquire Bone Marrow Syndrome
2-10 Grays
What percent of the average americans annual radiation comes from medical x-rays?
11%
What percent of the average american’s annual radiation comes from radon in the ground?
54%
