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Panoramic Imaging
Chapter 22 DNH 130
| Question | Answer |
|---|---|
| Purpose and Use of Panos | evalute impacted teeth evaluate eruption patterns detect diseases trauma eval 3rd molars |
| Does the patient sit or stand for panos | either |
| Is the receptor intraoral or extraoral | extraoral |
| Sectioning certain parts of the body for optimum viewing quality whiles blurring other images in other plans of film is called | tomography |
| The rotation center is | the point or axis around which the cassette carrier and tube head rotate |
| When the jaws are positioned outside the focal trough the image will appear...? | blurred or distorted |
| The focal trough is narrower in the anterior or posterior areas? | anterior |
| Define real image | structures that lie between the receptor and the moving rotation center and appear in the correct anatomic postions |
| focal trough | 3d curved zone where the dental arches must be positioned to achieve the clearest image |
| define double image | restulst when the atomic structure is behind the moving rotation center |
| causes of ghost images | earrings, glasses |
| example of double image | cervical spine |
| equipment associated with panos | xray unit screen film intestfying screen cassette |
| pano machine components | tube head head positoner exposure controls |
| What shape is the collimator for the pano | narrow rectangle |
| The tube head is in a fixed position and the ________ angulation cannot be changed | vertical |
| The beam is directed slightly ________ | upward |
| The parts of the head positioner | chin rest notched bite block forehead rest lateral head supports |
| What can be changed on the exposure control to accomodate a patients size? | kVp and mA |
| Is the exposure time fixed or variable? | fixed (10-30 secs) |
| Types of receptors based on the type of machine | digital phosphor film based |
| Two types of intensifying screens | calcium tungstate rare earth green |
| What are cassettes | devices to hold film and intensifying screen |
| Is the bite block disposable. | No, the bite block is covered with a barrier |
| do you use a lead apron with or without thyroid collar? | without |
| do you use a single sided or double sided apron? | double sided |
| Where do you direct the patient to put their tongue ? | roof of the mouth |
| What will happen if the tongue is not placed at the roof of the mouth? | a radiolucent shadow will appear over the apices of the maxillary anteriors |
| What can be used to help take a pano of an edentulous patient? | cotton rolls |
| What creates a cone shaped radiopacity on receptor images | lead apron artifact, apron was too high or thyroid collar was left on. |
| What causes the apices of the maxillary teeth to be obscured? | the tongue is not placed on the roof of the mouth |
| What causes the "reverse smile" | patients chin is tipped upward |
| What is the problem of a reverse smile | hard palate and floor of nasal cavity are super imposed over roots of max teeth loss of detail in max incisal area max incisors are blurred |
| what causes the "joker" or exaggerated smile line? | patients chin is tipped downward |
| What is the frankford plane? | the line that passes from the top of the ear canal to the outer canthus of the eye |
| What happens if the teeth are placed too far anterior on bite block? | anterior teeth appear skinny, out of focus overlapping pre molars |
| What happens if the teeth are placed too far posterior on bite block? | anterior teeth appear fat and out of focus |
| What happens if the patient is not centered midsaggitally | one side will appear more magnified |
| What causes the cervical spine to appear as radiopacity in center of film? | patient not sitting or standing up straight |
| Advantages of panos | field size simplicity patient cooperation minimal radiation |
| disadvantages of panos | image quality focal trough limitations distortion equipment cost |
Created by:
kbowman12
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