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RAD201 Exam 1
| What is ionizing radiation? | Radiation that produces positively and negatively charged particles when passing through matter |
| What are some consequences of ionization in human cells? | Creation of unstable atoms, production of free electrons, production of low-energy x-ray photons, creation of highly reactive free radicals, etc. |
| How do x-rays travel? | In straight lines at the speed of light |
| What is radiation protection? | Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation |
| What is Radiation Exposure? | Amount of radiation produced in air when ionizing radiation is present. Measured in coulomb per kilogram or milliroentgen. |
| What is Absorbed Dose? | The amount of energy that is deposited in a material per unit mass of the material. Measured in milligray. |
| What is Effective Dose? | A quantity that is a measure of general harm in humans. Measured in millisievert. |
| What is diagnostic efficacy? | The degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient. |
| What is ALARA synonymous with? | Optimization for radiation protection (ORP). |
| What are the three basic principles of radiation protection? | Time, Distance, and Shielding |
| What are some risks of imaging procedures? | The probability of injury, ailment, or death resulting from an activity. The possibility of inducing a radiogenic cancer or genetic defect after irradiation. |
| What is BERT? | A method used to improve understanding and reduce fear and anxiety for the patient. It compared the amount of radiation received with natural background radiation received over a period of time. |
| What are some advantages of the BERT method? | Does not imply radiation risk, emphasizes that radiation is an innate part of our environment. |
| Is there increased radiation sensitivity of children? | Yes, children are significantly more radiation sensitive than are adults. The more radiation exposure a child receives, the more likely for them to develop cancer later in life. |
| What is the Image Gently campaign? | It is a global education and awareness dedicated to promoting safe, high-quality pediatric medical imaging by minimizing radiation doses for children. |
| What is the Image Wisely campaign? | A social marketing and educational initiative to optimize adult radiation safety, minimize unnecessary procedures, and promote broader clinical safety across adult medical imaging. |
| What is the NEXT program? | Aka Nationwide Evaluation of X-ray Trends project in place to provide data on the measurement of radiation of x-ray machines. |
| What are reference values? | They are set at some fraction and these levels may be used to allow individual institutions to determine where they stand with regard to standard practices at the majority of institutions. |
| What are the protocols for dose alerts? | When patient dose is predicted to or has substantially exceeded present dose levels, the staff radiologist is notified. A physicist may be called to estimate patient doses such as effective dose, peak skin dose, or fetal dose. |
| What are the types of radiation? | Natural which are always present in the environment and human-made created by humans for specific purposes. |
| What is mechanical vibration of materials? | Ultrasound |
| Which types of radiation are electromagnetic waves? | Radio waves, microwaves, infrared, and visible light. |
| Which types of radiation are ultraviolet? | X-rays and gamma rays |
| What is the electromagnetic spectrum? | The full range of frequencies and wavelengths of electromagnetic waves. |
| What are the electromagnetic waves characterized by? | Their frequency and wavelength |
| What is the dual nature of electromagnetic radiation? | Aka wave-particle duality. This form of radiation can travel through space in the form of a wave but can interact with matter as a particle of energy |
| What is ionizing radiation? | It can transfer sufficient energy to some orbital electrons to remove them from the atoms to which they were atatched. |
| What is nonionizing radiation? | Does not have sufficient kinetic energy to eject electrons from atoms. |
| What is ionization? | Conversion of atoms to ions, makes tissues valuable for creating images, and undesirable result of potentially producing some damage in the biologic material. |
| What are alpha particles? | Contains two protons and two neutrons and emitted from nuclei of very heavy elements during the process of radioactive decay. |
| What are beta particles? | Has one unit of electric charge and capable of penetrating biologic matter to a greater depth than alpha particles with less ionization along their paths. |
| What is linear accelerator? | Produced in a radiation oncology treatment machine |
| What are protons? | Are positively charged components of an atom |
| What are neutrons? | Are electrically neutral components of an atom and have about the same mass as a proton |
| What are some examples of of natural radiation? | Terrestrial radiation, cosmic radiation, and internal radiation from radioactive atoms |
| What are some of the human-made radiation? | Nuclear fuel for generation of power, nuclear powerplant accidents, etc. |
| What is medical radiation? | Results from the use of diagnostic x-ray machines and radiopharmaceuticals in medicine |
| What are the two largest sources of artificial radiation? | Radiography, Fluoroscopy, and CT |
| The amount of radiation by a patient from diagnostic x-ray procedures mat be indicated in terms of what? | Entrance skin exposure, bone marrow dose, and gonadal dose |
| What is peak kVp? | The highest energy level of photons in the x-ray beam, equal to the highest voltage established across the x-ray tube |
| What is mAs? | The product of mA and the amount of time in seconds that the x-ray tube is activated |
| Dose the radiographer select technical exposure factors that control beam quality and quantity? | Yes |
| What are carriers of manmade electromagnetic energy? | X-rays |
| What is absorption? | Interaction where electromagnetic energy is transferred from the x-rays to the atom's of the patient's biologic tissue |
| When is a diagnostic x-ray beam produced? | A stream of energetic electrons bombards a positively charged target in a highly evacuated glass tube |
| Why are tungsten and tungsten rhenium used as target materials? | They have high melting points |
| What is primary radiation? | The x-ray photons beam energy from the x-ray tube and is directed toward the IR |
| Do all photons in a diagnostic x-ray beam have the same energy? | No |
| In diagnostic radiology, how is the voltage expressed? | In thousands of volts or kilovolts (kV) |
| What is transmission? | Photons that strike the IR are transmitted |
| What is direct transmission? | Some primary photons will traverse the patient without interacting and reach the IR |
| What is indirect transmission? | Other primary photons can undergo Compton and/or Coherent interactions and result may be scattered or deflected with a potential loss of energy |
| Is the interaction of photons with biologic matter random? | Yes |
| What are the 5 types of interaction? | Coherent scattering, Photoelectric absorption, Compton scattering, Pair Production, and Photodisintegration |
| What is Coherent Scattering? | Low-energy photons, less than 10 keV, there is no loss of energy as x-rays scatter, and no net energy ahs been absorbed by the atom |
| What is Photoelectric Absorption? | Most important for producing useful images; inner-shell electron is knocked out, creating a photoelectron, and releasing energy as a Characteristic or Auger electron |
| What is the Auger effect? | It is a radiationless effect |
| What are the byproducts of photoelectric absorption? | Photoelectrons and Characteristic x-ray photons |
| What is the probability of occurrence of photoelectric absorption? | Depends on energy of the incident x-ray photons and the atomic number of the atoms comprising the irradiated objects |
| True or False: The less a structure attenuates radiation, the darker the image will be and vice versa. | True |
| True or False: An image must have a sufficient amount of variation in densities to clearly visualize anatomic structures of interest | True |
| True or False: The greater the differences in the amount of photoelectric absorption, the greater the contrast in the radiographic image will be between adjacent structures of differing atomic numbers | True |
| Why would contrast media be used? | Tissues or structures of similar Z and mass density must be distinguished |
| What is Pair Production? | Energy levels of at least 1.022 MeV; an incoming x-ray photon interacts with the electric field of the nucleus and the energy is absorbed and transformed into a negatron and positron |
| What is Photodisintegration? | More than 10 MeV in high-energy radiation therapy treatment machines |
| What are some radiation quantities? | Exposure, air kerma, absorbed dose, equivalent dose, and effective dose |
| What are some radiation units? | Coulombs per kilograms, Gray, Centigray, and Milligray |
| What is exposure? | The total electric charge of one sign, per unit mass that x-ray and gamma ray photons with energies up to 3 MeV |
| What is the standard or free-air ionization chamber? | Type of direct measurement in an accredited dosimetry calibration laboratory |
| What is coulomb? | Basic unit of electric charge, equal to the "amount" of electrical charge moving past a point in a conduction in 1 second when an electric current amounts to 1 ampere is used |
| What is ampere? | SI unit of electric current and equal to an electric charge of 1 C produced in a kg of dry air by ionizing radiation |
| What is air kerma? | SI used to express how energy is transferred from a beam of radiation to a material like a patient's skin; expressed in J/kg or Gy |
| What is DAP? | The sum total of air kerma over the exposed area of the patient's surface or measure of the amount of radiant energy that has been thrust into a portion of the patients body surface |
| What is the radiation weighting factor? | Used to determine EqD, accounts for differences in biologic impact among various types of ionizing radiation |
| What is the tissue weighting factor? | The relative detriment to each specific organ and tissue, for EfD, percentage of the summed stochastic risk from irradiated tissue to the all-inclusive risk, risk to the entire organism by irradiation of individual tissues and organs |
| What is collective EfD? | Internal and external dose measurements, radiation exposure of a population/group from low doses of different sources of ionizing radiation |
| What is total effective dose equivalent? | Monitor and control human exposure to ionizing radiation; the sum of effective dose equivalent from external radiation exposure and a CEDE from internal radiation exposure |
| When is personnel monitoring required? | Wherever radiation workers have a risk of receiving 10% or more of the annual occupational EfD limit of 50 mSv in a single year |
| What is the purpose of personnel dosimeter? | Indication of the working habits and conditions, detects and measures the quantity of ionizing radiation where it has been exposed |
| What is the placement of personnel dosimeter? | Clothing on the front of the body at collar level |
| For pregnant workers, what is the placement of a personnel dosimeter? | Worn at collar level and second is worn at abdominal level |
| What do gas-filled detectors include? | Ionization chamber type survey meter, proportional counter, and GM survey meter |
| What are ionization chambers used to measure? | Radiation output from both radiographic and fluoroscopic x-ray equipment |
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