SC Dental Radiography Study Guide/Quiz – Flashcards
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Improper film positioning
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The correct placement of the xray film is the first and critical step in good exposure technique.
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Cone Cutting
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Cone cutting is result of a round cylinder not covering film surface after film placement . The error is caused when tube head being moved too far behind tooth of interest to assure inclusion of adjacent teeth. To correct ask patient to part their lips so you can see the edge of the film and place tube slightly in front of this point.
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Improper Horizontal Angulation (overlapping)
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Results in undiagnostic X-rays because teeth contacts cannot be properly accessed for caries. To correct, operator should "open the contacts" by selection of proper horizontal Angulation.
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Improper Vertical Tubehead Angulation
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Aligning the end of the cylinder with the ring of the film positioning device and parelleling the lengths of the indicating rod will ensure correct vertical Angulation
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Double Exposure
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Occurs by not separating exposed film. by placing exposed film a separate contAIner before selecting a new film will correct
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Film Backwards
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Placing film backwards in the film holder will result in a lighter than normal images (underexposed) and will cause confusion when mounting images. To avoid this easily identified problem remember the printed material on the film should not face the xray source.
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Improper Film Selection
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Can result in missing tooth or teeth of interest and discomfort intolerance for patient. The correct film size should cover the teeth of interest and be comfortable for patient
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Film bending
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Bending the film to adjust for patient comfort is acceptable however excessive bending May result in image distortion or crease marks
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Overexposure and Underexposed
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Overexposed (too dark) and underexposed (too light) films occur by inaccurate time and Kv settings.
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Exposure Time for operator safety
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Keep exposure time to radiation as short as possible. Mentally consider the recommended radiation safety precaution with every radiographic exposure.
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Using long exposure cords for operator protection
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Operator should stand at least 6 feet away from patients during xray exposures.
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Holding a patient or film for operator safety
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Never hold a patient or a film for patient. Ask parent or guardian.
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Light films (underexposed)
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May be unreadable because there is not enough contrast or detail for the dentist to read accurately
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Light films
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Light films may be caused by developing solution temperature too low
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Dark films
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Dark (overexposed) films are caused by too many X-rays striking the film resulting in undiagnostic X-rays.
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Dark films are caused by
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Light leaks and improper fixing
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Fogged films
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Films appear gray and hazy which affects the contrast and detail of the images and may mask dental problems.
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Stained films
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Occurs if any fluid dropped on an xray. It will cause visible stains or discoloration.
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Stained films may be caused by
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Water drops (clear spots) Fixer dropped or improper washing of fixer from films (yellow or brown stain). Developer (dark or black spots) Fluoride on hands (fingerprint artifact)
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Clinical compentecy
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Be assured of your clinical competency. Radiographic practice on patients should not begin until you have received training in exposure and processing skills and techniques by your dentist or through a structured educational radiology course.
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Correct positioning of patient and film
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Many retakes result in needless patient exposure are caused by hasty position of patient. Stop and ask dentist for assistance if unsure about positioning for specific view.
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Use E film
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High speed film means less radiation exposure time is needed to create image on film, thus exposing patient to less radiation.
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Choosing correct exposure factors
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Appropriate settings for time and kVp should be posted on control panel of xray unit
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Appropriate shielding
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Use aprons, thyroid shields and panoramic shields.
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Closing eyes during X-rays
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Have patient close their eyes during xray procedures. This will increase protection to eyes which may be exposed to the primary xray beam
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What are the two site near the oral cavity that are especially sensitive to radiation?
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Thyroid gland and lens of the eye. Thyroid shield are available and should be used with every patient. Patients should be asked to close their eyes during X-rays.
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What is ALARA
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Cumulative azure of radiation effects from all sources of radiation dictates we adhere to the ALARA concept. Which means "as low as reasonably achievable"
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How to avoid repeated X-rays
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Following the basic radiation protection guidelines spars the patient and operator from unnecessary radiation exposure.
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What does NCRP?
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National Committee Radiation Protection. They establish recommendations as to acceptable levels of exposure to ionizing radiation.
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What are the radiation recommendations referred to as?
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MPD- maximum permissible dose and are categorized for the general population, occupational worker and pregnant woman.
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What does the MPD represent?
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The greatest amount of radiation exposure accepted as not producing significant biological effects. No individual under 18 is permitted to work in such a position on the basis that growing and developing tissues are more susceptible to radiation injury.
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What is personnel monitoring?
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Devices or film badges to tell if you are recieving below the maximum permissible dose. These are plastic holders which contain radiographic fim. They are clipped to each individual employee's clot horse during the working day and measure amount of radiation you may be recieving.
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What are cones?
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Long, lead lined cones are recommended for modern dental radiography equipment. Pointed plastic cones are no longer recommended because of scatter radiation produced by xray beams passing through plastic cone before reaching patient.
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How much radiation can cause injury?
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Any amount of radiation no matter how small may be capable of producing some injury
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How does damage occur?
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When X-rays are absorbed by the tissues the molecules of the tissues are separated (ionized) into atoms and damage may result.
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What can cause sickness, cancer, birth defects or even death?
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Large doses of ionizing radiation
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Can damage be repaired?
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Most of the damage caused by low levels of radiation is repaired within the cells, tissues and organs of body.
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Chronic or repeated radiation exposure
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May lead to a minor percentage of unrepaired effects which accumulate in exposed tissues over a long period of time.
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Repeated exposures
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Increase the likelihood of an increased number of long term effects, especially the increase of certain diseases.
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Why does the dental assistant need to avoid unnecessary or careless radiation exposure?
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Because we don't know when the individual receives enough repeated exposures (doses) to make the accumulated harmful.
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Genetic effect
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Effect of radiation exposure to the reproductive cells causing altercations in genetic code which can possibly lead to mutations in offspring.
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Somatic effect
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Effects of radiation exposure that are expressed in the exposed person rather than the offspring. Like cataracts, cancers
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Three variable factors on the xray machine
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Kilovoltage Milliamperage and time
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Kilovoltage (kVp)
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The ability X-rays have to penetrate; affects the quality of radiographs produced.
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Milliamperage (mA) and time
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Determines the number of X-rays delivered (quantity) from the xray machine which are available to strike the film. This determines the darkness or lightness of the image produced.
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What is needed to make readable xray?
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All three settings of the machines must be properly set before the exposure button is depressed
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What are filters?
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Xray machine device which protects the patient by preventing non penetrating rays from stopping at the face.
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What is a collimator?
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Limits the size of the xray beam to the area
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Why do dentists use X-rays?
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Dental radiography provide useful information that many times cannot be obtained by a clinical examination alone.
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How does ionized radiation help?
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By using ionizing radiation, we now have the means to provide patients with early diagnosis and treatment of dental disease and patients can expect to maintain a functioning dentition for a lifetime.
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What are X-rays?
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They are invisible and travel in straight lines at a constant speed Are able to penetrate skin, teeth and bone Are capable of affecting body tissues and cells that carry hereditary materials for future generations
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What is a radiograph
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A photographic record that can be seen on film that is produced by passing X-rays and object or a body.
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What is essential in the practice of dentistry?
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Quality diagnostic radiographs
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What is equally important?
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The need to keep exposure to a minimum exposure for both patient and dental professional.
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What types of films do not have enough contrast or detail?
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Light
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Placing exposed film in a separate container will prevent
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Double exposure
