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RHS EXAM 2025 (440 Questions and Answers).
Electrons - Correct answer Beta particles = fast moving emmited from nucleus of radioactive atoms Cathode rays = high speed originate in xray tube Radiation - Correct answer Form of energy carried by waves or stream of particles Xray - Correct answer Beam of energy has power to penetrate substances and record image Dose rate - Correct answer Dose received over time , rapid delivery no time for body to repair Radiographs - Correct answer Picture or visible photographic image Total dose - Correct answer Quantity of radiation recieved or total amount of radiation energy absorbed Who's discovered radiographs? - Correct answer William roentgen Wavelength - Correct answer Detremines penetration power of beam Voltage - Correct answer Determines speed of electron as they move from cathode to anode Harder hit - shorter waves - high power 65-100kvp Kvp too high/low - Correct answer High KVP= high speed of electron = high penetration power= short waves = high intensity = high shades of grey = low contrast long scale
Low KVP = low speed of electrons= low penetration power= long waves = low intensity = low shades of gray = high contrast/black and white short scale Amperage - Correct answer Regulates temperautee of cathode/ heat Measures electrons moving through conductor #of electrons= # of xrays produced High milliamperage High electrons =more electron clouds, more xrays, increase intensity and density decrease exposure time Low electrons= less electron clouds = less X-rays less intensity and density increase exposure time MAS - Correct answer MilliampsXexposure time High MAS = low exposure time Low MAS = high exposure time Exposure time - Correct answer Quantity of xrays INCREASE Kilovolts - Correct answer How fast electrons move from cathode to anode INCREASE Milliamps - Correct answer More electrons created in cloud INCREASE Distance - Correct answer TRD greater =longer PID = less intense= less magnification TRD lesser = shorter PID = more intense = more magnification Increase ORD = increase magnification Decrease ORD = less magnification
1 sievert= 100 rem Average radiation - Correct answer 150-300 millirads ina year Minimizing exposure - Correct answer Espeed film rather than dspeed Rectangular colimnator rather than circular Long cone rather than short High kvp rather than low Filtration - Correct answer Inherent and added Inherent - Correct answer Primary beam
. 5- 1.0 mm alluminum Cannot work alone Added - Correct answer Alluminum disks .5 increments filters out long and low energy wavelenghts Total filtration - Correct answer Inherent plus added At or less than 70kvp = 1.5 mm alumminum more than 70kvp= 2.5 mm aluminnum Collimnator - Correct answer Restricts size and shape of beam Reduces exposure Round 2 Rectangle 2. PID - Correct answer Extension/ directs xray beam Conical PID - Correct answer Pointed plastic cone penetrate plastic produces scatter Round and rectangular PID - Correct answer Open ended lead liner limit scatter radiation Preferred long 16 and rectangular
Thyroid collar - Correct answer Flexible lead shield protects the thyroid from scatter radiation required for all intraoral do not use on extraoral Lead apron - Correct answer Chest and lap protects reproductive / blood forming tissues from scatter intra and extraoral use leadfree alloy 30% less weight Fast films - Correct answer F= fastest w/20% reduction Beam alignment - Correct answer Stabilized and reduces movement Exposure factor selection - Correct answer Adjusting KV / MA / time Limits amount of radiation exposure Setting 70-90 kvp is minumum Technique - Correct answer Diagnostic, routine , no retakes After exposure - Correct answer Receptors handled and processed meticulosly for HQ images Films/ sensor handling - Correct answer Artifacts caused by improper handling = no diagnostic Operator protection - Correct answer Avoid primary beam 6ft away from Tube head Perpendicular to primary beam Never hold receptor Never hold tube head Stand behind protective barrier or wall MPD - Correct answer Maximum permissable dose over a years time Workers- 5rem Patients 0.1 rem Pregnant 0.1 rem MAD - Correct answer Maximum accumulated dose current age -18 X 5
Atom becomes + Ejected electron becomes - They continue to react until electrically stable/ neutral Neutral atom - Correct answer Equal number of protons and electrons Unbalanced atom - Correct answer Incomplete outershell Tries to capture electron from another Gains = more electrons than protons = NEGATIVE loses = more protons than electrons = POSITIVE Radiation - Correct answer Energy in waves/ particles Radioactivity - Correct answer Unstable atoms undergo disintegration in effort to obtain more balanced nuclear state, gives off energy in particles, xray result Photons - Correct answer Weightless bundles of energy w/ out charge travel in waves and move through space in a straight lines with specific frequency at speed of light interact with materials penetrate and cause ionization Ionizing radiation - Correct answer Radiation capable of producing ions by adding and removing electrons Particulate or electromagnetic radiation Particulate radiation - Correct answer 4 types : electrons , alpha particles, protons, neutrons Have mass, high speed, travel in straight lines, transmit kinetic energy Alpha particles - Correct answer Emmited from nuclei of heavy metal 2 protons 2 neutrons 0 electrons
Protons - Correct answer Accelerated particles Hydrogen nuclei mass 1 charge + Neutrons - Correct answer Accelerated particles Mass 1 charge 0 Electromagnetic radiation - Correct answer Wavelike no mass natural manmade Cosmic rays Gamma rays Xray Uv ray Light Radiowave Microwave Electromagnetic spectrum - Correct answer Arrangement accorsing to energy ionizing and non ionizing Only high energy radiation (Cosmic rays Gamma rays Xray ) are capable of ionization Particle concept - Correct answer Characterizes electromagnetic radiation as photon or quanta Wave concept - Correct answer Velocity, wavelength, frequency Velocity - Correct answer Speed Wavelength - Correct answer Distance between one crest to the next Determined energy and power Short = high energy and ability to penetrate Frequency - Correct answer # of wavelength at given time High = wavelength is short
Lead collimator - Correct answer Restricts size of X-ray beam PID - Correct answer Aims/ shapes X-ray beam Lead glass housing - Correct answer Prevents X-rays from escaping in all directions Cathode - Correct answer Negative Supplies electrons necessary and electrons are accelerated to anode Tungsten filament produces electron cloud when heated Molybdenum cup focus / narrows electrons into beam Anode - Correct answer Positive Tungsten target concerts bombarding electrons into photons Copper stem dissipates heat from target Which of the following electrons has the greatest bonding energy? - Correct answer K shell electrons What type of electrical charge does the electron carry? - Correct answer Negative Which term describes two or more atoms that are joined by chemical bonds ? - Correct answer Molecule Which of the following describes ionization? - Correct answer Atom that loses electron Which term describes process by which unstable atoms undergo spontaneous disintegration in an effort to attain a more balanced nuclear state? - Correct answer Radioactivity Which of the following is not a part of particulate radiation? - Correct answer Nucleons
Which is not a type of electromagnetic radiation? - Correct answer Electrons Which of the following regulates flow of electrical current to the filament of the xray tube? - Correct answer Low voltage circuit Which of the following is used to increase voltage in high voltage circuit? - Correct answer Step up transformer What occurs when high voltage circuit is activated? - Correct answer Unit produces audible and visible signal Electrons produced at cathode are accelerated across tube to anode Heat is produced Which of the following is the location where X-rays are produced? - Correct answer Positive anode Which of the following is the location where thermionic emission occurs? - Correct answer Negative cathode Which of the following accounts for 70% of all X-rays produced at anode? - Correct answer General radiation Which occurs only at 70kvp or higher and accounts for very small part of X- rays produced in dental X-ray machine? - Correct answer Characteristic radiation. Which describes primary radiation.? - Correct answer Radiation that exits tube head Describe scatter radiation - Correct answer Radiation that has been deflected from its path by interaction with matter Which scatter occurs more often with dental X-rays? - Correct answer Compton Circuit - Correct answer Path of electrical current
Thermionic emmision - Correct answer Release of electrons cloud from tungsten filament when electrical current passes and heats it How much percentage is converted into X-rays - Correct answer Less than 1% 99% lost as heat X-rays should have? - Correct answer High frequency Short waves General radiation - Correct answer Sudden stopping of high speed electrons where they hit the tungsten target in the anode Electron may hit nucleus or pass very close Hit = high energy X-ray photon Miss= low energy X-ray photon Characteristic radiation - Correct answer High speed electron dislodges an inner shell electron from the tungsten atom and causes ionization of that atom Primary radiation - Correct answer Refers to the penetrating X-ray beam produced at target of anode and exits tube head aka useful beam Secondary beam - Correct answer Radiation created when primary beam interacts with matter it's less penetrating Scatter radiation - Correct answer Form of secondary results from X-rays that have deflected their path by interaction with matter Interactions of radiation - Correct answer Passes through patient hits the receptor causes no ionization 30% is absorbed scatter can occur In a dental radiograph quality of the X-ray beam is controlled by - Correct answer Kilovoltage peak Identify kilovoltage for most machines - Correct answer 65000-
Higher kilovoltage produces X-rays with - Correct answer Greater energy levels Shorter wavelengths More penetrating ability Identify unit of measurement used to describe amount of electric current flowing through X-ray tube - Correct answer Ampere Radiation produced with high kilovoltage results in - Correct answer Short wavelengths Quantity of radiation is produced by - Correct answer Milliamperage and exposure time Increasing milliamperage increases - Correct answer temperature of filament and number of X-rays produced Milliamperage range - Correct answer 7- 15 mA Overall blackness or darkness of an image is termed - Correct answer Density If kilovoltage decreased with no other variations in exposure factors the resultant image will - Correct answer Appear lighter Identify the term that describes how dark and light areas are differentiated in an image - Correct answer Contrast Radiograph that has many light and dark areas with few shades if grey - Correct answer High contrast produced with low kilovoltage Increasing milliamperage alone results in an image with - Correct answer Increased density Diagnostic image is produced at 90kvp and 0.25 seconds what exposure time in needed for 70kvp - Correct answer .50 seconds Total energy contained in X-ray beam in a specific area at a given time is - Correct answer Intensity
Which of the following statements is correct - Correct answer Long term effects are seen with small amount of radiation absorbed in a long period Which is most susceptible to ionizing radiation? - Correct answer Small lymphocyte Sensitivity of tissues to radiation is determined by - Correct answer Mitotic activity Cell differentiation Cell metabolism Which is radio-resistant - Correct answer Mature bone cells Organ that if damaged diminished the quality of an individuals life is termed
- Correct answer Critical organ Measure X-ray exposure in air - Correct answer Roentgen Which of the following units is determined by quality factor? - Correct answer R.E.M. Unit for measuring absorption of X-ray - Correct answer Rad Which conversion is correct - Correct answer 1R = 2.58X10^-4C/Kg Which of the following traditional units does not have an SI equivalent? - Correct answer Roentgen Amount of radiation exposure an individual receives varies depending on - Correct answer Film speed collimation technique exposure factors Which of the following is not a component of inherent filtration - Correct answer a) oil b) unleaded glass window c) leaded cone d) tubehead seal C
Which is most effective method of reducing patient exposure to radiation? - Correct answer Fast film Which restricts size and shape of X-ray beam - Correct answer Collimator Which is used as a collimator? - Correct answer Aluminum plate What if the function of filtration? - Correct answer Reduce low energy wavelengths Recommended size of beam - Correct answer 2. Describes dose of radiation that the body can endure with little or no chance of injury? - Correct answer Maximum permissible dose MAD No federal standard existed for dental X-ray machines before - Correct answer 1974 Component part of X-ray machine that contains X-ray tube is - Correct answer Tubehead Component part of X-ray machine that allows movement and positioning of tubehead is termed - Correct answer Extension arm Can regulate X-ray beam through use of - Correct answer Control panel Instrument used to position PID in relation to tooth and receptor - Correct answer Beam alignment device Device used to stabilize intraoral receptor - Correct answer Film holder Metal instrument used to restrict size of X-ray beam to size of intraoral receptor - Correct answer Collimating device Radiation control for health and safety act - Correct answer Federal level 1968 Standardize operation of X-ray equipment Consumer radiation health and safety act - Correct answer 1981
When exposed screens convert X-ray into light exposing film Sensitive to fluorescent light rather than direct exposure to X-ray Blue sensitive film - Correct answer Must be paired with screen that produces blue light Green sensitive film - Correct answer Must be paired with screen that produces green light Nonscreen film - Correct answer Does not require use of screens and is exposed directly to X-rays rather than fluorescent light Phosphors - Correct answer When exposed to X-rays phosphors fluoresce giving off light that exposed film Calcium tungstate film - Correct answer Emits blue light Rare earth - Correct answer Emits green light More efficient that calcium tungsten Requires less radiation Types of cassettes - Correct answer Rigid, flexible, light tight, Storage of film - Correct answer Fridge 50-70 degrees F Film can be affected by? - Correct answer Heat humidity radiation What should you check on film? - Correct answer Expiration date What will an old film look like - Correct answer Foggy Chemical compound that changes when exposed to light or radiation - Correct answer Halide Invisible pattern of stored energy on exposed film - Correct answer Latent image
Dental X-ray film placed inside the mouth and used to examine the teeth and supporting structures is termed - Correct answer Intraoral Identification dot is significant because - Correct answer Indicates patients left and right side Determined film orientation Important for mounting Advantage to film with emulsion on both sides is - Correct answer Film requires less radiation exposure to make an image Purpose of lead foil sheet in film is - Correct answer Protect film from backscatter radiation Which is not found on label side of film packet - Correct answer Expiration date Which film is standard - Correct answer Size 2 Largest film - Correct answer Size 4 Film characteristic that is the amount of radiation needed to produce radiograph of standard dentistry is - Correct answer Speed Speed of film is determined by size of silver halide crystals Emulsion identify the correct statement - Correct answer The larger the crystal the faster the film speed Film paced outside mouth - Correct answer Extraoral Screen film is more sensitive to fluorescent light that exposure to X-ray - Correct answer True Nonscreen extraoral film in commonly used - Correct answer True Device that transfer X-ray energy into visible light - Correct answer Intensifying screens
