17 Questions
What is the unit of the effective dose of ionizing radiation?
Sievert (Sv)
What is the primary mechanism by which ionizing radiation causes indirect effects on biological molecules?
Ionizing water molecules to form free radicals that interact with biological molecules
Which of the following is NOT a tissue weighting factor (WT) used to calculate the effective dose of ionizing radiation?
Brain
What was the first recorded biological effect of radiation described by Becquerel?
Skin erythema (redness)
Which of the following is NOT a potential source of ionizing radiation exposure mentioned in the text?
Medical imaging procedures
What is the primary mechanism by which ionizing radiation causes direct effects on biological molecules?
Directly breaking chemical bonds in biological macromolecules
Which type of effects caused by x-rays do not have a threshold for expression?
Cancer
What is the primary reason for about 2/3 of the biological damage caused by x-rays?
Indirect action via radiolysis of water
Which process leads to the formation of hydrogen and hydroxyl free radicals during x-ray exposure in the human body?
Radiolysis of water
What percentage of the biologic effects of x-ray exposure result from indirect effects?
2/3
Which type of effects demonstrate a threshold for expression due to radiation dose/dose rate?
Genetic defects
What is the term used to describe sublethal damage to individual cells that results in cancer formation or heritable mutation?
Gene mutation
Which of the following is an example of a deterministic effect of radiation?
Xerostomia
What principle emphasizes minimizing exposure to ionizing radiation in dental procedures?
ALARA Principle
In the context of radiation safety, what does ALARA stand for?
As Low As Reasonably Achievable
What effect does the replication of mutated cells following DNA damage typically lead to?
Heritable disorders
Which of the following is an example of an indirect effect of radiation exposure on oral tissues?
Teeth Caries
Test your knowledge on the biological effects of x-ray exposure, including direct and indirect effects on DNA. Learn about free radicals, radiolysis of water, and the impact of x-rays on DNA strands.
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