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For Radiation Protection purposes, high LET is one of the greatest concerns when a radionuclide has been implanted, ingested, or inhaled because.....
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Free radicals behave as an extremely reactive single entity as a result of what presence?
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Chapter 7
Radiation Proctection
| Question | Answer |
|---|---|
| For Radiation Protection purposes, high LET is one of the greatest concerns when a radionuclide has been implanted, ingested, or inhaled because..... | The potential exists for irreparable damage because multiple strand breaks in DNA are possible. |
| Free radicals behave as an extremely reactive single entity as a result of what presence? | Unpaired Electrons |
| What is classified as a high LET? | High- Alpha particles. |
| A biological reaction is produced by 3 Gy, of a test radiation. It takes 12 Gy of 250kVp x-radiation to produce the same biological reaction. What is the relative biological effectiveness (RBE) of the test radiation? | 4 |
| What action of ionizing radiation is the most harmful to the human body? | Indirect action |
| What molecule in the human body are most commonly directly acted on by ionizing radiation to produce molecular damage through an indirect action? | Water |
| When does ionizing radiation cause complete chromosome breakage? | When two direct hits occur in the same rung of the DNA macromolecule |
| When significant numbers of lymphocytes are damaged by exposure from ionizing radiation, the body does what? | 1. Loses its natural ability to combat infection. 2. Becomes more susceptible to bacteria. 3. Becomes more susceptible to viral antigens. |
| With respect to the law of Bergonie and Tribondeau, which of the following would be best complete this statement? "The most pronounced radiation effects occur in cells having the______" | Greatest reproductive activity, longest mitotic phases, and least maturity. |
| What do basal cells of the skin, intestinal crypt cells, and reproductive cells have in common? | All cells are radioscensitive |
| Biologic damage that occurs as a result of ionization of atoms on master, or key molecules(DNA) that causes these molecules to become inactive or functionally altered? | Direct action |
| The average energy deposited per unit length of track | LET |
| Chemical unions created between atoms by the single sharing of one or more pairs of electrons | Covalent Cross links |
| Used to calculate the equivalent dose to determine the ability of a dose of any kind of ionizing radiation to cause biologic damage | Radiation weighing factor (Wr) |
| Loss or change of a nitrogenous base in the DNA chain | Mutation |
| Method of displaying the sensitivity of a particular type of cell to radiation | Cell Survival curve |
| Effects produced by reactive free radicals, which are created by the interaction of radiation with a water molecule | Indirect action |
| Ratio of the radiation dose required to cause a particular biological response of cells or organisms in an oxygen deprived environment to the dose required to cause an identical response under normal oxygenated conditions | OER |
| Programmed cell death | Apoptosis |
| Lesions that occur when irradiation occurs early in interphase, before DNA synthesis takes place | Chromosomes aberrations |
| Concept that the cell dies if inactivation of the master, or key molecules occurs as a result of exposure to ionizing radiation | Target theory |
| The relative capabilities of radiation with differing LET's to produce a particular radiation reaction | RBE |
| Lesions that result with irradiation of individuals chromatids occur later in interphase, after DNA synthesis takes place | Chromatids aberrations |
| The radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation | Law of Bergonie and Tribondeau |
| Solitary atoms or most often a combination of atoms that behave as extremely reactive single entities as a result of the presence of unpaired electrons | Free Radicals |
| Exposing a cell to as little as 0.01 Gy of ionizing radiation just before it begins dividing can result in failure of the cell to start dividing on time. | Mitotic delay |
| An organic neutral free radical | R |
| Injury on the molecular level resulting from exposure to radiation | Molecular damage |
| A hydroperoxyl radical | HO2 |
| Female and male reproductive cells | Germ cells |
| Branch of biology concerned with the effects of ionizing radiation on living systems | Radiation biology |
| OH* + OH*=H2O2 (A substance that is poisonous to the cell) | Hydrogen peroxide |
| Genetic mutation in which the chromosome is not broken but the DNA within is damaged | Point Mutation |
| H* and OH | A hydrogen radical and a hydroxyl radical |
| Radiation is observed on what 3 levels? | Molecular, cellular, and organic |
| Molecular damage results in the formation of structurally what? | Changed molecules that may impair cellular function |
| According to the target theory, if only a few non DNA cell molecules are destroyed by radiation exposure, the cell will do what? | Not show any evidence of injury after irradiation |
| Each cells function is determined by and defined by the structures of its constituent molecules. If these structures are altered by radiation. What will happen? | 1. Disturbance of the cell's chemical balance 2. Disturbance of cell operation 3. Failure of the cell to perform normal taks |
| Chromosome aberrations occurs when radiation occurs when? | Early in Interphase |
| What are examples of distorted chromosomes? | Anaphase bridges, Dicentric chromosomes, and ring chromosomes. |
| What is useful for explaining the cell death and nonfatal cell abnormalities caused by exposure to radiation? | Target theory |
| X-rays and gamma rays can be referred to as "streams of particles" because of what property? | Wave particle duality |
| The random interactions of x-rays with matter produces a variety of structural changes in biologic tissue containing what? | 1. A single strand break in a chromosome. 2. More than one break in the same chromosome. 3. Stickiness, or clumping together of chromosomes. |
| Why are repair enzymes usually able to reverse the cellular damage generally caused by low energy x-rays? | Damage to DNA is sublethal |
| What governs the radiation dose required to cause apoptosis? | The radio sensitivity of the individual cell |
| What describes the ratio to the radiation dose required to cause a particular biologic response of cells or organisms in an oxygen deprived environment to the radiation dose required to cause an identical response under normal oxygenated conditions? | OER |
| What is a method of displaying the sensitivity of a particular type of cell to radiation? | Cell survival curve |
| Where are lymphocytes manufactured in the human body? | Bone marrow |
| What defines the ratio of the dose of a reference radiation (conventionally 250 kVp) to the dose of radiation of the type in question that is necessary to produce the same biologic reaction. What is the RBE of the test radiation? | RBE |
| A hydroperoxyl radical is formed when a hydrogen free radical combines with what? | Molecular oxygen |
| LET is a important factor for what? | Assessing potential tissue and organ damage from exposure to ionizing radiation |
| Because high energy LET produces more energy per unit length of biological tissue traversed are? | More destructive to biological matter than low energy radiation |
| Ring chromosomes, dicentric chromosomes, and anaphase bridges have in common? | Distorted chromosomes |
Created by:
J_Proctor