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Radpro-1
| X-rays are a form of ________ radiation. | ionizing |
| _______ may be defined simply as effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation. | Radiation protection |
| ______ can be described as damage to living tissue of animals and humans exposed to radiation. | Biologic damage |
| Name the consequences of ionization in human cells. | 1. unstable atoms 2. free electrons 3.low energy x-ray photons 4. Creation of reactive free radicals capable of producing substances poisonous to the cell 5. Creation of new biologic molecules detrimental to the living cell 6. Injury to the cell tha |
| What is considered to be the most effective tool for diagnosing breast cancer early? | Mammography screening |
| ______ is the degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient. | Diagnostic efficacy |
| Both _____ and ______ have a responsibility for radiation safety in the medical industry. | 1. employees of medical workers 2. workers themselves |
| ______ can be defined as the probability of injury, ailment, or death resulting from an activity. | Risk |
| What do the letters BERT stand for? | Background Equivalent Radiation Time |
| BERT is based on an annual U.S. population exposure of approximately _____mSV per year. | 3 mSv (300 mrem) |
| Using the BERT scale, a chest radiograph is approximately equivalent to how much exposure in nature? | 10 days |
| Using the BERT scale, a lower GI series is approximately equivalent to how much exposure in nature? | 12 years |
| ________may be defined as energy in transit from one location to another. | Radiation |
| Which type of particulate radiation is essentially a helium nucleus? | Alpha |
| What is the difference between Equivalent dose (EqD) and the effective dose (EfD)? | Equivalent dose is the variation in biologic harm from difference types of radiation. Effective dose is the dose for all radiation taking into account the quality factor and risk of genetic damage. |
| Name the three components of natural background radiation. | 1. Terrestrial 2. Cosmic 3. Internal (from radionuclides) |
| Name the two nuclear power plant accidents discussed in Chapter 1. | 1. Three Mile Island 2. Chernobyl |
| The amount of energy absorbed per unit mass refers to ______. | absorbed dose (D) |
| When an x-ray beam passes through an object, it goes through a process known as ________, which is simply the reduction in the number of primary photons in the x-ray beam through absorption and scatter as the beam passes through the object. | attenuation |
| Scatter radiation reaches the image receptor by means of _______ transmission. | indirect |
| Scatter radiation adds unwanted shaped of gray to the image. These undesirable, additional densities are called_________. | Compton fog |
| Of the five interactions between x-radiation and matter, which two are of importance in diagnostic image formation? | Compton and Photoelectric |
| Interactions between incoming photons and the nucleus of the atom begin at what energy level? | 1.022 MeV |
| Which interaction is responsible for most of the scattered radiation produced during radiologic procedures? | Compton scattering |
| The probability of occurence of photoelectric absorption depends on the energy of the incident x-ray photon and the __________. | atomic number of the absorbing material |
| The use of contrast media increases the probability of which interaction? | photoelectric |
| Pair production does not occur unless the energy of the incident photon is at least ______ MeV. | 1.022 |
| As part of the pair production interaction, the nucleus emits matter in the form of a _______ and antimatter in the form of a ________. | 1. negatron 2. positron |
| ________is biologic damage to the body of an individual after exposure to ionizing radiation. | Somatic damage |
| In the very early years of experimentation withe the use of radiation, many radiologists and dentists developed a reddening of the skin called ________. | radiodermatitis |
| Name the short-term somatic effects. | 1. Nausea 2. Fatigue 3. Diffused redness of the skin 4. Loss of hair 5. Intestinal disorders 6. Fever 7. Blood disorders 8. Shedding of the outer layer of the skin |
| Name the long-term or late somatic effects. | 1. Cancer 2. Formation of cataracts 3. Embryologic effects (birth defects) |
| Name the genetic effects (heritable effects). | Biologic effects of ionizing radiation on generations yet unborn |
| From 1900 to 1930 the unit in use for measuring radiation exposure was called the _______ dose. | skin erythema |
| Why was the skin erythema dose not an accurate measure of radiation exposure? | The same dose of radiation affected each person differently |
| The unit Rem stands for ________. | Radiation Equivalent Man |
| Fluoroscopic entrance exposure rates are measured in ________. | Roentgen per minute (R/min) |
| The SI unit of absorbed dose is the ______. The traditional unit for absorbed dose is the _______. | 1. Gray 2. RAD |
| The ________ is the unit used for expressing exposure in air. | Roentgen |
| The _______ is the basic unit of electrical charge. | coloumb |
| The quantity, ________, is defined as the amount of energy per unit mass absorbed by the irradiated object. | absorbed dose (D) |
| What is the quality factor for an x-ray photon? | 1 |
| What is the quality factor for a gamma photon? | 1 |
| What is the quality factor for a fast neutron? | 20 |
| What is the quality factor for an alpha particle? | 20 |
| What is the quality factor for a beta particle? | 1 |
| _______ is the amount of energy transferred on average by incident radiation to an object per unit length of track through the object. | Linear Energy Transfer (LET) |
| The letters Wr stand for __________. | radiation weighting factor |
| The letters Wt stand for__________. | tissue weighting factor |
| 1 rad equals _______ Gray | 0.01 |
| 1 Gray equals ______ rad | 100 |
| 1 rem equals ______ sieverts | 0.01 |
| 1 sievert equals ______ rem | 100 |
| Another name for the production of low energy photons as a consequence of ionization in human cells is called __________. | characteristic cascade |
| _______ is defined as any exposure that does not benefit a person in terms of diagnostic or therapeutic application. | Unnecessary radiation |
| The ______ carries the responsibility for determining medical necessity. | ordering physician |
| What does ALARA stand for? | As Low As Reasonably Achievable |
| Using BERT has what advantages? | 1. Does not imply radiation risk 2. Emphasizes that radiation is an innate part of our environment 3. Comparison makes it easy for the patient to understand |
| Higher frequencies have a ______ wavelength and _____ energy. | shorter |
| higher | |
| Electromagnetic spectrum is divided into _______ and _______ types of radiation. | ionizing |
| nonionizing | |
| The ionizing radiation on the electromagnetic spectrum include _____ and ______. | x-rays and gamma rays |
| Electromagnetic radiation that has high enough frequency to transfer energy to an atom and eject an electron is known as _________. | ionizing radiation |
| ______ are emitted from nuclei of heavy elements (uranium, plutonium) during radioactive decay. | Alpha particles |
| _______ is a naturally occurring process where unstable nuclei relieve instability by emitting charged particles. | Radioactive decay |
| -essentially a helium nuclei -has two protons and two neutrons - large mass -positively charged -less penetrating -lose energy quickly -virtually harmless externally -considered harmless if emitted from internal source of radiation (isotope injecte | Alpha particle |
| -identical to high speed electrons (only difference is source) -small mass (8,000 times smaller than alpha particle) - negative charge - more penetrating -requires minimum of 1mm of Pb or equiv to stop - | Beta Particle |
| -positively charged component of an atom -small mass, but larger mass than electron | proton |
| electrically neutral component of an atom -approx. same mass as proton | neutron |
| A quantity that attempts to take into account the variation in biologic harm that is produced by different types of radiation -enables calculation of effective dose | Equivalent Dose (EqD) |
| -takes into account all of the organ weighting factors -represents the whole body dose that would give an equivalent biologic response | Effective Dose (EfD) |
| Radiation interaction at the atomic level results in ______ change and may cause cellular damage. | molecular |
| If excessive cellular damage occurs, the organism may exhibit ______ or _______ changes. -mutations, cataracts, leukemia | genetic or somatic |
| - changes in blood count -may occur with whole body does of 0.25 Sv (25 rem) -drop in WBC count -may occur within a few days of exposure | organic damage |
| This Radiation equivalent dose may result in changes in blood | 0.25 Sv (25 rem) |
| This Radiation equivalent dose may result in nausea or diarrhea | 1.5 Sv (150 rem) |
| This Radiation equivalent dose may result in Erythema | 2 Sv (200 rem) |
| This Radiation equivalent dose may result in temporary sterility | 2.5 Sv (250 rem) |
| This Radiation equivalent dose has a 50% chance of death | |
| lethal dose for 50% of the population over 30 days (LD 50/30) | 3.0 Sv (300 rem) |
| This Radiation equivalent dose has a result of death | 6.0 Sv (600 rem) |
| What are the sources of natural radiation? | 1. radon 2. cosmic 3. terrestrial 4. internal |
| What are the sources of manmade radiation? | 1. medical x-rays 2. nuclear medicine 3. consumer products |
| These sources of radiation are in what category? occupational, fallout, nuclear fuel cycle, miscellaneous, environmental sources | other |
| What is the largest contributor to background radiation? -avg dose is 1.98 mSv (198 mrem) from this | radon (55%) |
| -results from nuclear interactions from within the sun or other stars -avg dose is 0.3 mSv (30 mrem) from this | cosmic radiation |
| unstable nucleus that emits one or more forms of ionizing radiation to achieve greater stability | radionuclide |
| These elements result from what process? potassium, carbon, hydrogen, strontium | radioactive decay |
| Nuclear fuel for generation of power does/does not contribute significantly to the dose of the U.S. population? | does not |
| -1979 -Harrisburg, PA -severe overheating of one of the reactors -no significant leaks | Three Mile Island |
| -1986 -Russia -Explosion of one of the reactors -1 million times the amt of radiation released in Three Mile Island incident | Chernobyl |
| What is the main adverse health effect from the Chernobyl incident? | thyroid cancer |
| -1996 -aided exposed community in Russia in rebuilding the area | ETHOS project |
| These are methods to measure radiation exposure | ESE, glandular dose, bone marrow dose, gonadal dose, fetal dose |
| The amount of energy absorbed per unit mass is the _________. | absorbed dose (D) |
| Process that decreases the intensity of the primary photon beam | attenuation |
| This is a total loss of radiation energy | absorption |
| This is a partial loss of radiation energy | scatter |
| Photons that pass through the object being radiographed and reach the image receptor | Exit, or image formation, photons |
| Photons that have interacted with an atom of the object and was scattered or absorbed such that they did not reach the image receptor | attenuated photons |
| -have essentially the same energy as the incident photon -degrades the appearance of the image -referred to as "fog" | small angle scatter |
| ______ reduces fog as well as overall patient dose. | Collimation |
| This interaction has a slight change in direction (less than 20 degrees), but no change in energy -Occurs below 30 KeV -Produces fog that is not significant to diagnostic imaging | Coherent/unmodified/classical/Thompson/Rayleigh |
| What is the byproduct of coherent scattering? | None |
| -responsible for most of the scattered radiation during radiographic procedures -may be directed forward, backward, or as side scatter | Compton scattering |
| -encounters loosely bound outer shell electron and surrenders a portion of its energy to dislodge the electron -energy degraded x-ray photon continues on its way in a NEW direction -high speed electron ejected from it's orbit is called this | Compton scatter or recoil electron |
| Compton scattering increases as photon energy ___________. | increases |
| -increases radiographic fog -increases risk of health hazard to radiographer and radiologist -source of occupational exposure | Compton Scattering |
| What are the byproducts of Compton scattering? | 1. Compton scattered electron or recoil electron 2. Compton scattered photon |
| -on encountering an inner shell electron, or k shell electron, the incoming x-ray photon surrenders all of its energy to the electron and the photon ceases to exist -atom responds by ejecting electron and creating a vacancy in that shell | Photoelectric Absorption |
| At what Kv level is there a 1:1 ratio of Compton and Photoelectric interactions? | 40 Kv |
| What are the byproducts of photoelectric absorption? | 1. Photoelectrons 2. Characteristic Photons |
| This interaction results in an increase in patient dose and an increased risk of biologic damage | Photoelectric Absorption |
| The probability of occurrence of a photoelectric interaction depends on _______ and _______. | 1. the energy of the x ray photon 2. the atomic number of the absorbing material |
| Absorption increases as _____________ increases and decreases as ______________increases. | atomic number |
| photon energy | |
| -incoming photon of 1.022 MeV strongly interacts with the nucleus of the atom of the irradiated object and disappears -energy of photon transformed into negatron and positron | Paired Production |
| ______eventually interacts with any atom that needs another electron. | Negatron |
| ______interacts destructively with a nearby electron. | Positron |
| -incoming high energy photon collides with the nucleus of the atom and absorbs all of the photons energy -energy excess in the nucleus creates an instability (usually alleviated by emission of a neutron) | Photodisintegration |
| This interaction makes a nucleus radioactive | Photodisintegration |
| Somatic damage as a result of exposure was first noted in Europe in _____. | 1896 |
| ______ was the first radiation fatality in America in 1904. | Clarence Daly |
| _______resulted in the reddening of the skin of the exposed individual. - known as radiodermatitis -seen as skin lesions | Occupational exposure |
| -1900-1930 -early unit of radiation exposure -defined as the received quantity of radiation that causes diffuse redness over an area of skin after irradiation | Skin erythema dose |
| A dose in which occupationally exposed persons could be continuously subjected without any apparent acute harmful effects. | Tolerance dose |
| A dose of radiation below which an individual has a negligible chance of sustaining specific biologic damage - belief was that no adverse effects would be demonstrated below this dose | Threshold/Tolerance dose |
| -introduced in the early 1950s -indicated largest dose of ionizing radiation that an occupationally exposed person was permitted that was not anticipated to result in major adverse biologic effects -no bodily injury or injury to reproductive cells were | Maximum Permissible Dose (MPD) |
| Risk is ______ lowered to zero. | NEVER |
| -based on energy deposited in biologic tissue -takes into account the type of radiation and the sensitivity of the specific tissue -measure of overall risk -measured in Sv or mSv | Effective Dose (EfD) |
| -measurement of exposure to x and gamma radiation -radiation in air | Roentgen |
| -Equivalent Dose (EqD) -dose that is equivalent to any type of ionizing radiation that produces the same biologic effect as 1 rad of x-radiation -quality of dose -shows damaging effects | Rem/Sievert |
| -radiation absorbed dose -unit that indicates the amount of radiant energy transferred to an irradiated object by any type of ionizing radiation -quantity of dose | Rad/Gray |
| -Fluoroscopic entrance exposure rates are measured in this unit -most radiation survey instruments use this instrument | Roentgen per minute (R/min) |
| -the amount of ionizing radiation that may strike an object such as the body when in the vicinity of a radiation source -DOES NOT necessarily indicate dose | Exposure |
| -the deposition of energy per unit mass by ionizing radiation in the patient's body tissue -ACTUAL "dose" from exposure -absorption by different tissues is determined by the atomic number of the structure, mass density of the tissue, and the energy of t | Absorbed Dose (D) |
| -traditional unit is rad -SI unit is gray | Absorbed Dose (D) |
| -different types of radiation produce different amounts of biologic damage in tissue -this is used to account for the differences in radiation types and damaging effects for each, a modifier is introduced | Quality Factor |
| -adjustment multiplier that was used in the calculation of dose equivalent to specify the ability of a dose of any kind of ionizing radiation to cause biologic damange -x-rays, beta particles, and gamma rays produce virtually the same biologic effect for | Quality Factor |
| -based on Linear Energy Transfer (LET) | Quality Factor |
| Defined as the amount of energy transferred on average by incident radiation to an object per unit length track through an object -expressed as keV/micromillimeter | Linear Energy Transfer (LET) |
| -product of the average absorbed dose in a tissue or organ in the body -includes its associated radiation weighting factor | Equivalent Dose (EqD) |
| nonthreshold, randomly occurring biologic effects of ionizing radiation such as cancer and genetic abnormalities -probability of occurrence depends on the radiation dose and the type and energy of the radiation | Stochastic effects |
| -provides a measure of the overall risk of exposure to ionizing radiation -NCRP report | 116 defines it as the sum of the weighted equivalent doses for all irradiated tissues or organs -incorporates type of radiation used and the radiosensitivity of the organ being irradiated |
| -conceptual measure for the relative risk associated with irradiation of different tissues -value that denotes the percentage of the summed stochastic risk stemming from irradiation of tissue to the all-inclusive risk | Wt (tissue weighting factor) |
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nastronomical