Radiologic Procedures – Facial Bones Imaging Techniques & Interpretation Study Guide – Practice Questions and Review Material

Collimation for facial bones 6x6 PA routine for facial bones -PA Caldwell -Waters -Lateral -SMV PA Caldwell CR, center pt., baseline, MSP -CR 30 degrees caudal @ nasion -OML perp -MSP perp PA Caldwell demos orbits and foramen rotundum PA Caldwell projection name PA Axial Waters CR, center pt., baseline, MSP -CR perp @ acanthion -MML perp making OML= 37 degree angle to IR -MSP perp Waters demos inferior orbital margin, nasal septum, maxilla, zygoma, and zygomatic arches possible blowout fx Waters projection name parietoacanthial is the mouth open in a waters facial bones no lateral CR, center pt., baseline, MSP -CR perp @ zygoma -IOML // -MSP // how can you find the zygoma midway between the outer canthus and EAM lateral facial bones demos all facial bones and bottom of mandible SMV facial bones CR, center pt., baseline, MSP -CR angled cephalic until perp to IOML -center pt.= 1" posterior to outer canthus -IOML // -MSP perp SMV facial bones demos zygomatic arches free of SI SMV projection name inferior superior SMV method name Schuller method what to do for a depressed zygomatic arch rotate head 15 degrees towards affected side and tilt chin 15 degrees towards affected side center directly at the affected arch AP facial bones routine -AP Caldwell -AP Waters -Townes -Lateral -SMV AP Caldwell everything the same except CR is 30 cephalic modified waters projection name acanthioparietal modified waters CR, center pt., baseline, MSP -CR perp @ acanthion -LML perp OML= 55 degree angle to IR -MSP perp modified waters demos blowout fx how to know if the OML is forming a 55 degree angle in a modified waters nose and chin will touch table modified waters replaces what 30 degree caldwell why does a modified waters better show a blowout fx than a regular waters it places the floor of the orbit perp to the IR patient position for a modified waters prone Townes CR, center pt., baseline, MSP -CR 30 caudal @ glabella -OML perp -MSP perp Townes demos zygomatic arches where is the glabella located 1" superior to the nasion nasal bones routine waters and bilaterals collimation for nasal bones smaller than a 6x6 waters for nasal bones CR, center pt., baseline, MSP -CR perp @ acanthion -MML perp OML= 37 degree angle to IR -MSP perp waters for nasal bones demos deviated septum waters for nasal bones projection name parietoacanthial lateral nasal bones CR, center pt., baseline, MSP -CR perp @ 1/2" distal to nasion -IOML // -MSP // lateral nasal bones demos nasal bone, anterior nasal spine, and frontal nasal suture lateral nasal bones are done... bilaterally RAD PROCEDURES & IA: FACIAL BONES EXAM (LATEST 2025/2026 UPDATE) ACTUAL EXAM QUESTIONS WITH CORRECT ANSWERS RATED A+ Routines for: -facial bones -nasal bones -mandible -Orbits -Waters, Lateral, AP Axial (modified), SMW for arches -Waters and both laterals -PA, PA Axial, Axiolateral, Axiolateral Oblique -Waters, maybe Rhese ways to eliminate shoulder in an image: -angle (head) MSP 15 degrees toward IR -put 10 angle on CR to maintain 25 degrees Projection to demonstrate blowout fx of orbit: Modified Parietoacanthial (waters) Centering for reverse waters and trauma reverse waters: -reverse: CR enters acanthion (MML perp) -trauma reverse: CR matches angle of MML and =; enters acanthion (apx 30 degree ceph) SMV for zygo arches vs SMV for skull: -arches: no grid; less penetrate; less mAs; CR enters 1" post to outer canthus -skull: grid; more penetrate; more mAs; CR enters 3/4" ant to EAM Tangential Zygomatic Arch: -rotate MSP of head 15 towards IR -tilt top of head 15 away from examined side -CR enters 1" posterior to outer canthus (skimming arch) foreshortening: -appears shorter than it is -occurs when part not = to IR elongation: -appears longer than it is -tube or IR not properly aligned or there's an angle on the tube advantages of a PA Axial Mandible: -places mandible closer to IR (reduces mag. and improves detail) -easier for hypersthenic patient Modified waters: -less hyperextension of neck (OML forms 55 angle to IR) -PP immediately below inf. border of orbits -orbital floor = to IR AOI: -Lat facial bones -Lat nasal bones -all facial bones (side down) -nasal bones (side down) AOI: -Waters -Towne -arches, maxillae, orbits, and nasal bones -arches, rami and body of mandible AOI: -SMV -Tangential Arch -zygo arches -zygo arch AOI: -PA and PA Axial Mandible -Axiolateral -Axiolateral Oblique -body and rami -ramus (side down) -body (30 degrees) or mentum (45 degrees) For the tangential projection of the zygomatic arch, the central ray is directed perpendicular to the _____ line. IOML At which level will the central ray be placed for the tangential projection of the zygomatic arch? level 1" posterior to outer canthi Which of the following is placed perpendicular to the image receptor for the acanthoparietal projection (reverse Waters method) of the facial bones? MML RADIOLOGY FINAL EXAM REVIEW FOR CH 4-6 (LATEST 2025/2026 UPDATE) QUESTIONS WITH CORRECT ANSWERS RATED A+ Short term effects of radiation Associated with large doses of radiation in a short amount of time Acute radiation syndrome (ARS) Includes nausea, vomiting, diarrhea, hair loss, hemorrhage Short-term effects are not applicable to dentistry. Following the latent period, effects that are seen within minutes, days, or weeks are termed Short term effects of radiation Note: Short-term effects are not applicable to dentistry. Long term effects of radiation -Small doses absorbed repeatedly over a long period of time -Effects seen after years, decades, or generations -Repeated low levels of radiation exposure are linked to the induction of cancer, birth abnormalities, and genetic defects. All the cells in the body can be classified as either ______________ or ______________ Somatic or Genetic Somatic effects of radiation Changes to the exposed individual that are not passed on to offspring Genetic Effects of Radiation changes that are passed on to the next generation due to radiation in gonads A cell that is sensitive to radiation is termed _____________; one that is resistant is termed ______________. radiosensitive, radioresistant Cells that divide frequently or undergo many divisions over time are more sensitive to radiation. mitotic activity Cells that are immature or are not highly specialized are more sensitive to radiation. cell differentiation Cells that have a higher metabolism are more sensitive to radiation. cell metabolism Cells that are radiosensitive include blood cells, immature reproductive cells, and young ______ cells Bone The cell that is most sensitive to radiation is the small ________________________ Lymphocyte Radioresistant cells include cells of _________, __________, __________ Bone, Muscle & nerve cells In dentistry, some tissues and organs are designated as "___________" because they are exposed to more radiation than are others during imaging procedures. Critical A Critical organ is is an organ that, if damaged, diminishes the quality of a person's life. Critical organs exposed during dental imaging procedures in the head and neck region include the following: * Thyroid gland • Bone marrow • Skin • Lens of the eye The term exposure refers to refers to the measurement of ionization in air produced by x-rays. The traditional unit of exposure for x-rays is Roentgen (R) The roentgen is a way of measuring radiation exposure by determining the amount of ionization that occurs in air radiation exposure on cells, tissues, and organs and identify the relative sensitivity of a given tissue to x-radiation. units of measurement used in radiation exposure. total dose Quantity of radiation received, or the total amount of radiation energy absorbed. More damage occurs when tissues absorb large quantities of radiation. An example of total-body irradiation is the exposure of a person to a nuclear energy disaster. Extensive radiation injury occurs when large areas of the body are exposed because of the damage to the _____________-________________ tissues. Blood-forming The radiation absorbed dose, or _______, is the traditional unit of dose. RAD ---A special unit of absorbed dose that is equal to the deposition of 100 ergs of energy per gram of tissue (100 erg/g) RAD (Radiation absorbed dose) Cell sensitivity More damage occurs in cells that are most sensitive to radiation, such as rapidly dividing cells and young cells Cell sensitivity More damage occurs in cells that are most sensitive to radiation, such as rapidly dividing cells and young cells Different types of radiation have different effects on tissues. The __________ _____________________ measurement is used to compare the biologic effects of different types of radiation. Dose Equivalent Dose Rate Rate at which exposure to radiation occurs and absorption takes place (dose rate = dose/time). More radiation damage takes place with high dose rates because a rapid delivery of radiation does not allow time for the cellular damage to be repaired. Amount of tissue irradiated: Areas of the body exposed to radiation. Total-body irradiation produces more adverse _________________ effects than if small, localized areas of the body are exposed. Systemic Medical Imaging includes? Medical radiation includes medical imaging procedures, dental imaging, fluoroscopy, radiation therapy, nuclear medicine, and computed tomography (CT) imaging. Radiation exposure can be reduced by using _________ sensors. Digital The use of sensors can reduce exposure time by 50% to 90% when compared to conventional radiography. The average person is exposed to approximately ___._ mSv of human-made radiation per year. 3.1 mSv ______________ radiation is the greatest contributor to human-made radiation exposure. Medical Children are _________ susceptible to radiation damage than are adults. More Radiation exposure can be limited by using the fastest film available. The use of __- __________ film instead of D-speed reduces the absorbed dose by 60%. F-speed film Radiation exposure can be limited by using a ______________________ collimation Rectangular collimation - use of the rectangular, instead of round collimation, reduces the absorbed dose by 60% to 70%. In the United States, the average person is exposed to a total of __._mSv of radiation per year 6.2 mSv (3.1 mSv from natural sources + 3.1 mSv from human-made sources = 6.2 mSv total) Radiation exposure can be limited by increasing the ___________-_______________ distance. The use of the paralleling technique and increased target-receptor distance reduces the skin dose. Target-Receptor The latent period in radiation biology is the time between: a. initial injury and repair b. subsequent doses of radiation c. cell rest and cell mitosis d. exposure to x-radiation and clinical symptoms e. none of the above d. exposure to x-radiation and clinical symptoms A free radical: a. is an uncharged molecule b. has an unpaired electron in the outer shell c. is highly reactive and unstable d. combines with molecules to form toxins e. all of the above e. all of the above Direct radiation injury occurs when: a. x-ray photons hit critical targets within a cell b. x-ray photons pass through the cell c. x-ray photons are absorbed and form toxins d. free radicals combine to form toxins e. none of the above A. x-ray photons hit critical targets within a cell Indirect radiation injury occurs when: a. x-ray photons hit critical targets within a cell b. x-ray photons pass through the cell c. x-ray photons are absorbed and form toxins d. x-ray photons hit the DNA of a cell e. none of the above C. X-ray photons are absorbed and form toxins Which relationship describes the response of tissues to radiation? a. linear b. linear, threshold c. linear, nonthreshold d. nonlinear, nonthreshold e. none of the above C. Linear, nonthreshold Which factor(s) contributes to radiation injury? a. total dose b. dose rate c. cell sensitivity d. age e. all of the above e. all of the above Which statement is correct? a. Short-term effects are seen with small amountsof radiation absorbed in a short period. b. Short-term effects are seen with small amounts of radiation absorbed in a long period. c. Long-term effects are seen with small amounts of radiation absorbed in a short period. d. Long-term effects are seen with small amounts of radiation absorbed in a long period. e. None of the above. D. Long-term effects are seen with small amounts of radiation absorbed in a long period. Radiation injuries that are not seen in the person irradiated but that occur in future generations are termed: a. somatic effects b. genetic effects c. cumulative effects d. short-term effects e. long-term effects B. Genetic Effects Which is most susceptible to ionizing radiation? a. bone tissue b. small lymphocyte c. muscle tissue d. nerve tissue e. epithelial tissue B. Small Lymphocyte The sensitivity of tissues to radiation is determined by: a. mitotic activity b. cell differentiation c. cell metabolism d. all of the above e. none of the above d. all of the above Which is considered radioresistant? a. immature reproductive cells b. young bone cells c. mature bone cells d. epithelial cells e. none of the above c. mature bone cells An organ that, if damaged, diminishes the quality of an individual's life is termed: a. critical b. somatic c. cumulative d. radioresistant e. none of the above critical The traditional unit for measuring x-ray exposure in air is termed: a. gray b. coulombs per kilogram c. rem d. rad e. roentgen E. The Roentgen Which radiation unit is determined by the quality factor (QF)? a. roentgen b. rad c. rem d. gray e. coulombs per kilogram c. REM The unit for measuring the absorption of x-rays is termed: a. roentgen b. rad c. rem d. quality factor e. sievert b. rad Which traditional unit does not have an SI equivalent? a. roentgen b. rad c. rem d. quality factor e. none of the above A. Roentgen Which conversion is correct? a. 1 R = 2.58 × 10-4 C/kg b. 1 rad = 0.1 Gy c. 1 rem = 0.1 Sv d. 1 Gy = 10 rad e. 1 Sv = 10 rem a. 1 R = 2.58 × 10-4 C/kg Which is used only for x-rays? a. sievert b. gray c. rem d. rad e. roentgen E. The Roentgen What is the approximate average dose of background radiation received by an individual in the United States? a. 100 mrem/0.01 mSv b. 100 mrem/1.0 mSv c. 300 mrem/3.0 mSv d. 500 mrem/5.0 mSv e. 1000 mrem/10.0 mSv C. 300 mrem/3.0 mSv What is the greatest contributor to artificial radiation exposure? a. radioactive materials b. medical radiation c. consumer products d. weapons production e. nuclear fuel cycle B. Medical Radiation The amount of radiation exposure an individual receives varies depending on: a. receptor type b. collimation c. technique d. both a and b e. all of the above e. all of the above Which statement is incorrect? a. X-radiation is not harmful to living tissues. b. Dental images benefit the patient. c. In dental imaging, the benefit of disease detection outweighs the risk of damage from radiation. d. Dental images should be prescribed only when the benefit outweighs the risk. e. Biologic damage results from x-ray exposure. A. X-radiation is not harmful to living tissues The ______________________ _______________________ dose (MPD) is defined by the National Council on Radiation Protection and Measurements (NCRP) as the maximum dose equivalent, that a body is permitted to receive within a specific period. Maximum Permissible Dose (MPD) A single intraoral image using a digital sensor results in an effective exposure dose of: a. 0.002 mSv b. 0.020 mSv c. 0.200 mSv d. 2.000 mSv e. 20.00 mSv d. 2.000 mSv What is the dose at which leukemia induction is most likely to occur? a. 500 mrad (0.005 Gy) b. 1000 mrad (0.01 Gy) c. 2000 mrad (0.02 Gy) d. 5000 mrad (0.05 Gy) e. none of the above d. 5000 mrad (0.05 Gy) The MPD is the maximum dose of radiation that the body can endure with _________ or ____injury. Little or No For pregnant dental personnel, the radiation exposure limit is ____ mSv per month during pregnancy months. 0.5 mSv For nonoccupationally exposed persons (i.e., the general public), the current MPD is approximately __mSv/year . 1mSv/year (0.1 rem/year) MPD for occupationally exposed persons, or those who work with radiation (e.g., dental radiographers), is ____ mSv/year. It is recommended that dental radiographers not exceed a maximum dose of 50 mSv in any 1 year. 50 mSv/year (0.05 Sv/year or 5.0 rem/year) It is recommended that dental radiographers not exceed a maximum dose of 50 mSv in any 1 year. Occupationally exposed workers must not exceed an accumulated lifetime radiation dose. This is referred to as the _____________________ ________________________ ________ cumulative occupational dose ALARA concept As Low As Reasonably Achievable T/F Every patient should be evaluated individually prior to prescribing dental images. True T/F The 8-inch PID is more effective than the 16-inch PID in reducing radiation exposure of the patient. False T/F: Pointed cones should not be used because of increased scatter radiation. True T/F: The thyroid collar must be worn for both intraoral and extraoral exposures. False T/F: If necessary, the dental radiographer may hold a receptor in the patient's mouth to ensure a diagnostic image. False Which statement describes the function of a filter in a dental x-ray tubehead? a. It reduces the size and shape of the beam. b. It removes low-energy x-rays. c. It removes the dose of radiation to the thyroid gland. d. It decreases the mean energy of the beam. b. It removes low-energy x-rays. Which is the most effective method of reducing patient exposure to radiation? a. lead apron b. fast films c. circular PID d. film-holding devices b. fast films Which is not a component of inherent filtration? a. oil b. unleaded glass window c. a leaded PID d. tubehead seal c. a leaded PID Which position-indicating device is most effective in reducing patient exposure? a. conical b. rectangular c. circular d. all are equally effective in reducing patient exposure b. rectangular Which device restricts the size and shape of the x-ray beam? a. filter b. collimator c. barrier d. film badge b. collimator Which material is used as a collimator? a. lead b. aluminum c. copper d. all of the above A. Lead Which describes the function of filtration? a. increases scatter radiation b. increases divergent rays c. increases long wavelengths d. reduces low-energy waves d. reduces low-energy waves Which is the recommended size of the beam at the patient's face? a. 2.75 inches b. 3.25 inches c. 3.50 inches d. 4.00 inches A. 2.75 inches Which term describes the dose of radiation that the body can endure with little or no chance of injury? a. radiation limit b. maximum permissible dose c. occupationally exposed dose d. ALARA b. maximum permissible dose Which statement is true of a radiation monitoring badge? a. It should be worn when the radiographer is undergoing x-ray exposure. b. It can be shared between employees. c. It should be worn at waist level when exposing x-ray receptors. d. All of the above are true. C. It should be worn at waist level when exposing x-ray receptors Machines operating at 70 kV or lower require __________ mm aluminum. 1.5 Machines operating above 70 kV require __________ mm aluminum. 2.5 State the angle at which the dental radiographer should stand in relationship to the primary beam:__________ degrees. 90-135 State the formula for the cumulative occupation dose: workers age x 10 mSv State the maximum permissible dose for occupationally exposed persons: __________ mSv/year (__________ rem/year). 5.0 mSv/year; 0.05 Sv/year What is a BAD Beam Alignment Device is used to help the dental radiographer position the PID in relation to the tooth and the receptor. A collimating device may be used to further __________ the size of the x-ray beam and _________ patient exposure. Restrict , Reduce No federal standards existed for dental x-ray machines manufactured before the year: a. 1954 b. 1964 c. 1974 d. 1984 c) 1974 Dental receptors placed inside the mouth are termed: a. intraoral b. extraoral c. occlusal d. all of the above A. intraoral The component part of the dental x-ray machine that contains the x-ray tube is termed the: a. control panel b. tubehead c. extension arm d. console B. Tubehead The component part of the dental x-ray machine that allows movement and positioning of the tubehead is termed the: a. control panel b. extension arm c. console d. position-indicating device (PID) b. extension arm The dental radiographer can regulate the x-ray beam (kilovoltage, milliamperage, time) through the use of the: a. control panel b. extension arm c. tubehead d. PID A. Control Panel An instrument that is used to help the dental radiographer position the PID in relation to the tooth and receptor is the: a. receptor holder b. beam alignment device c. collimating device d. none of the above B. Beam alignment device A device that is used to stabilize an intraoral receptor is termed: a. beam alignment b. collimator c. receptor holder d. none of the above c. receptor holder Which one is used to restrict the size of the x-ray beam to the size of an intraoral receptor? a. collimating device b. receptor holder c. beam alignment device d. none of the above A. collimating device T/F the federal government dictates how dental x ray equipment is used False T/F State and local governments dictate codes that pertain to the use of dental x-ray equipment. True T/F: Portable dental x-ray units are approved in all states. False T/F: Studies have shown that a portable dental x-ray unit can be used to produce highquality diagnostic images. True T/F: With a portable dental x-ray unit, operator exposure is limited by using a lead acrylic disk shield around the PID. True T/F: An example of a collimating device is the Tru-Align Aiming Device. True T/F: An example of a beam alignment device is the Snap-A-Ray. False