Limited Scope of Practice in Radiography Exam Questions Answers PDF Limited-Scope preparation is essential for achieving success in any examination, and leveraging secondary keyword materials can significantly enhance your readiness. Practice exams, question answers, PDFs, and dumps specifically tailored to the limited-scope focus area offer targeted insights and help streamline your study efforts. These resources provide a comprehensive understanding of the subject matter, allowing you to refine your knowledge and tackle the exam with confidence. Click here for more information: https://www.certswarrior.com/exam/limited-scope/ Question: 1 Shielding against which of the following sources of ionizing radiation is the MOST difficult to provide? A. Magnetic resonance imaging (MRO B. Computed tomography (CT) C. Flat film X-radiography D. Positron emission tomography (PET) Answer: D Explanation: Radiation from isotopes used in positron emission tomography (PET) comes from positrons emitted from atomic nuclei, when protons convert to neutrons. The positrons meet up with electrons (also called negatrons), and each positron/electron pair is annihilated. The result is gamma radiation, which is very penetrating. Shielding humans from this type gamma radiation is challenging. Magnetic resonance imaging CMRI) is not a source of ionizing radiation since it uses a magnetic field and radio waves to produce images. Computed tomography (CT) and flat film radiography both use X-rays, which can be blocked effectively with lead and other materials made of large atoms. Question: 2 Radioactive dose absorbed by a material is expressed by using which of the following SI units? A. Becquerel (Bq) B. Gray (Gy) C. Sievert (Sv) D. Rad Answer: B Explanation: The radioactive dose absorbed by a material is expressed in grays (Gy). According to the Systeme Internationale (SO, the becquerel (Bq) measures radioactivity, or 1 unit of atom disintegration per second. A sievert (Sv) refers to the absorbed dose equivalent in terms of the biological effect of radiation on human tissue in comparison to the effects of X-rays. For example, 1 Sv is the absorbed dose of any type of ionizing radiation producing biological effects equivalent to I Gy of X-ray exposure. A rad was the term used for the absorbed radioactive dose in the past; the current term used is a Gray. One rad equals 0.01 Cry. Question: 3 Which of the following instruments detects X-rays by utilizing a low pressure gas that is ionized when radiation strikes it? A. Scintillator B. Gamma camera C. Geiger-Müller counter D. Photostimulable phosphor plate Answer: C Explanation: A Geiger-Müller detector, or counter, detects ionizing radiation when a low pressure gas (helium, argon, or neon, plus halogens) is ionized after being struck by radiation. A scintillator is any material that becomes luminescent after it is excited by incoming radiation. Radiation striking the material is absorbed by electrons, which then give off energy as photons of visible light. A gamma camera is a type of scintillation detector that uses an array of photomultiplier tubes to form images, for instance, medical imaging after patients have ingested gamma-emitting radionuclides. A photostimulable phosphor plate is treated with photoluminescent phosphors that capture X-ray images. Question: 4 Ionizing radiation doses associated with flat film chest radiography (lateral or posterior- anterior) typically fall within which of the following ranges? A. 5—10 microsieverts (μSv) B. 10-100 μSV C. 0.1-1.0 millisieverts (mSv) D. 5-100 mSv Answer: B Explanation: Flat film chest X-ray radiography (lateral and posterior-anterior) typically imparts ionizing radiation doses in the range of 10 to 100 microsieverts (uSv), although this dose may be higher. Five to 10 LLSv would be the range for typical dental X-rays, although certain dental X-rays could exceed it. Most medical imaging procedures do not impart exposures of more than a few millisieverts (mSv), the range that most people receive yearly from natural radiation sources. There are certain exceptions, notably computed tomography (CT) scanning, which exposes patients to radiation doses in the multiple mSv range, as high as 40 mSv for whole body scans. Question: 5 Which of the following represents the maximum dose of ionizing radiation dose that a declared pregnant worker may receive during the gestational period? A. 0.5 millisieverts (mSv) B. 5 mSv C. 150 mSv D. 500 mSv Answer: B Explanation: During the gestational period, a pregnant worker who has declared her pregnancy may receive no more than 5 millisieverts (mSv) of exposure to ionizing radiation. Generally, supervisors prefer to keep their pregnant workers below this limit. If a declared pregnant worker's dose exceeds this limit (based on her radiation badge readings), she will not be assigned duties that will increase her exposure. To appreciate how conservative this occupation exposure limit is, keep in mind that the average exposure to ionizing radiation from natural background sources for an individual living in the United States is 3 mSv per year, or up to 6 mSv per year in high altitude locations such as Denver and Salt Lake City. If a radiation worker does not declare her pregnancy, her supervisor is not required to know about it, and thus has no obligation to change her duties. Other occupational dose limits include the maximum yearly exposure of the lens of the eye (150 mSv) and the maximum yearly exposure to any organ (500 mSv). Question: 6 Which of the following sources accounts for most of the ionizing radiation to which human beings are exposed regularly? A. Medical procedures and waste B. Nuclear power plants C. Uranium released from coal burning D. Galactic cosmic radiation, solar radiation, radon gas, soil, and rocks Answer: D Explanation: Ionizing radiation comes from a variety of natural sources, which together account for approximately 80 percent of the exposure that most individuals receive. Galactic cosmic radiation consists of gamma rays, X-rays, neutrons, and heavy particles resulting from explosions of distant stars. Solar particle events send particles from the Sun toward Earth, and the Sun sends out X-rays and ultraviolet radiation constantly. While Earth's magnetic field and atmosphere prevent most space radiation from reaching the surface, a small amount penetrates. Ionizing radiation is also emitted from uranium in rocks radon gas and soil. When functioning correctly, the reactors at nuclear power plants do not release much radiation. Coal burning plants release more radioactivity than nuclear plants, because coal contains radioactive uranium and thorium, which are released into the atmosphere in concentrated form in fly ash, the by-product of combusted coal. Question: 7 Following nuclear accidents, such as the one that occurred at the Fukushima Daiichi power plant in Japan in 2011, which of the following is the greatest long-term health concern? A. Lung cancer, due to the release of radon gas B. Breast cancer, due to X-ray beam radiation C. Thyroid cancer, due to high levels of iodine-131 D. Bone cancer, due to high levels of calcium-45 Answer: C Explanation: After accidents involving nuclear reactors, long-term health concerns focus particularly on iodine-131 and cesium-137, both of which may be produced in significant quantities. Iodine-131 is absorbed by the thyroid, where it releases radiation in the form of beta particles, with some gamma rays. Beta particles can damage thyroid cells and cause cancer. Consequently, thyroid cancer always is a major concern following nuclear accidents. Radon gas has been implicated in lung cancer, but is released naturally from the ground, not from a nuclear accident. X-rays are typically produced by X- ray equipment used in diagnostic medicine. In nuclear accidents, X-rays may be produced through bremsstrahlung and K-shell effects, when beta particles from decaying radionuclides interact with materials made of large atoms. However, this effect is not significant enough to be a concern. Similarly, calcium-45, a radionuclide used in certain diagnostic applications, is not a particular concern in a nuclear accident. Question: 8 The ionizing effect that X-rays have on biological tissue refers to which of the following? A. The membranes surrounding cells are heated, compromising their integrity. B. Electrons are removed from atoms and molecules within the tissue. C. Watery tissue is separated from fatty tissue. D. The nuclei within cells are nudged away from the cell centers. Answer: B Explanation: When radiation strikes an electron, it absorbs the energy. If a great deal of energy' is absorbed, the electron is launched out from the atom or molecule. This is ionization. X-rays are a type of ionizing radiation that can damage biological tissue when DNA is altered. Infra-red radiation is not ionizing. though it can generate enough heat to damage tissue. Tissue contains both fatty and watery parts, while nuclei of atoms can exist in many different locations throughout a cell. Very rarely is a nucleus located precisely in the center of a cell. Question: 9 X-rays can be produced through all of the following mechanisms, EXCEPT: A. Bremsstrahlung B. K-shell emission C. Synchrotron radiation D. Electron-positron annihilation Answer: D Explanation: Electron-positron annihilation is a type of matter-antimatter annihilation reaction in which particles which have the same mass but opposite charge meet up and are annihilated, causing their combined mass to be converted to energy'. Quantified by the equation E=mc:, the energy is released as gamma ray photons, not X-rays. The bremsstrahlung effect occurs when electrons collide with large atoms, such as those of lead or tungsten, producing X-rays which are emitted perpendicular to the path of the electrons. K-shell emission refers to the process in which a particle, usually an electron, knocks an electron out from the K-shell, the lowest energy shell of an atom. Since this liberates a spot in the K-shell, an electron from a higher energy shell can drop down to the K-shell. In doing so, it releases energy as a photon in the X-ray range of the electromagnetic spectrum. Synchrotron radiation results when electrons are accelerated in a spiral course around a magnetic field, causing photons of various wavelengths to be radiated. These photons are usually in the radio range of the electromagnetic spectrum, but many energies are possible, including those in the X-ray range. Question: 10 Which of the following is true, regarding the megavoltage range for X-ray machines? A. They operate in the range of 30-150 kilovolts. B. This is the intermediate range for X-ray intensity. C. It is used for common diagnostic applications, such as radiography to detect fractures. D. It involves devices such as betatrons and linear accelerators. Answer: D Explanation: Megavoltage X-ray machines use devices such as betatrons and linear accelerators that operate above 1,000 kilovolts (kV). X-ray tubes that supply an electric potential in the range of 30 to 150 kV are used for superficial therapeutic applications. Orthovoltage X-ray radiation is an intermediate type that employs from 120 to 1,000 kV. An X-ray machine with a voltage of X would be most appropriate for diagnostic imaging of a bone fracture. Unlock the full potential of your Limited-Scope exam preparation with meticulously curated secondary keyword materials. Dive deep into practice exams, meticulously crafted question answers, comprehensive PDFs, and insightful dumps that mirror the format and complexity of the actual test. These resources act as invaluable companions, guiding you through key concepts and ensuring you are well-equipped to tackle every challenge that the limited-scope examination may present. Click here for more information: https://www.certswarrior.com/exam/limited-scope/