Ch 17_Panoramics

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- The cassette with image receptor and the x-ray tube head move in directions opposite each other

- x-ray tube head moves around the back, while the cassette with image receptor moves around the front.

- The x-ray beam enters the patient's tissues from the back of the head penetrating through to exit the front tissues and strike the image receptor

- The narrow vertical beam of radiation then passes through the patient and through a secondary collimator vertical slit in the cassette holder to expose the image receptor that is moving or rotating in the opposite direction
Enter from back of head (back side areas too) and exit through the front tissues to strike the image receptor in the cassetteThe xray beams for a panoramic enter the patient where? and exit where?The Right Side, with the Left side being blurred out as a "ghost Image"When the tube head of a Panoramic Xray is directing a beam through the patients Left Side, what side of the mouth will be recorded?the axis on which the x-ray tube head and the cassette rotate (CenterPoint in the oral cavity where the beam rotates 360)Explain what the "Rotational Center" is?10 - 30%All panoramic images have between 1_____ & _____ percent image magnification(Intraoral) concentric or rectangular beam (Pano) Narrow, vertical slit = a limited area of tissue recorded at a timeXrays emerge in what type of opening from the Tube Head for Intraoral Xrays vs. Panoramic Xrays?(1) anterior-posterior (2) lateral or left-right (3) superior-inferior or up-downWhat are the (3) dimensions of the Focal Trough ?Wider = Posteriors Narrower = AnteriorsThe panoramic x-ray machine's moving center rotation system results in a focal trough that is naturally wider in the ________ regions and narrower in the ________ regions3 - 4mmIt is important to note that a mistake in positioning the arches in the anterior region of the focal trough by as little as _____ to______mm will make a significant difference in the degree of magnification on the resultant radiograph.the arrangement of their pixels *Panos are a narrower band of pixels (not as sharp)The major difference between intraoral digital sensors and those used for panoramic imaging is ________?.5 X 12 6 X 12Panoramic photostimulable phosphor (PSP) imaging plates are available in what (2) sizes for Panos?Used in FILM to transfer x-ray energy into visible light by crystals that burn fluorescent and emit energy when absorbing xrays = a image produced on the filmWhat is an Intensifying Screen?1) Rotational x-ray tube head 2) Cassette holder (for film or PSP plate) or built-in digital image receptor 3) Head positioner guides to assist with locating the patient within the focal trough 4) Exposure control panelAll panoramic x-ray machines have which four basic com- ponents?in a vertical position / -8The PID used with the panoramic tube head is in a fixed ________ position pointing up slightly, about _____ degrees.Head Positioners GuidesBecause the focal trough is determined and set by the machine manufacturer we must use the _____ _______ ______the kV settingsWhat do you often adjusted up when exposing larger patients or denser tissues, and adjusted down when exposing children and patients with significant edentulous regions(Extraoral) No thyroid collar, swooping neckline and covers the patients back as well (Intraoral) has a thyroid collar and no backingWhat is the difference in Lead Aprons for Extraoral Xrays vs. Intraoral Xrays?palatoglossal air spaceThe open air space between the tongue and the roof of the mouth is also known as _______?it will create a large radiolucency on the image that will obscure the root apices of the maxillary teeth = creates a more even density for the Palatoglossal Air SpaceIf the patient doesnt touch the tip of their tongue to their palate during the procedure what will happen?- Open lips will create an image of the Lip Line that can mimic caries of the anterior teethIf a patient fails to close their lips around the bite block during the Xray procedure what can happen?edge to edgeWhen using a biteblock the patient must bring both maxillary and mandibular central incisors into an _______ position on the biteblockthe midsagittal plane that divides a patient's head into a right and left side must be positioned perpendicular to the floor.How do you determine the patient is in the correct Lateral Position?ala-tragus line—an imaginary plane or line from the bottom of ala to the tragus of the ear —must be positioned approximately 5 degrees down toward the floor. Frankfort plane—an imaginary plane or line from the orbital ridge (under the eye) to the external opening of the ear—will be parallel to the floor.What are two ways to determine the patient is in the correct Superior - Inferior position?Frankfort plane—an imaginary plane or line from the orbital ridge (under the eye) to the external opening of the ear—will be parallel to the floor. Ensures patient is in the correct Superior - Inferior PositionWhat is the Frankfort Plane? What is it used to determine?(Anterior) blurred anterior teeth and prominent imaging of spinal column on both sides. (Posterior) widened and magnified anterior teeth.Arches too far anterior result in what? Arches too far posterior result in what?Narrower MagnificationArches tilted too far to one or the other side of focal trough results in a _______ appearance of teeth on the side closer to the image receptor and a ________ of teeth on the side closer to the x-ray tubeslant out of focal troughArches too inferior (chin tipped down) & Arches too superior (chin tipped up) causes root apices of mandibular anterior teeth to ________ ?(Too Inferior) = a "Smile" , causes the nasopharyngeal air space to be larger and darker = a reduced image (Too Superior) = a "Frown" , obscures root apices of Max teethArches too inferior result in a characteristic ______ appearance, mandibular condyles slant inward, and causes what? Arches too superior result in a characteristic _______ appearance, and obscures what?a wide radiopacity at center inferior border of imageIf a patient is not standing straight and has Compressed vertebrae (slumped positon) it will appear on the Xray where?+5 degrees (slightly pointed down)If the Frankfort plane is parallel to the plane of the floor, then the ala-tragus line will be approximately ___________ degrees to the plane of the floor.ensure the light beam goes through the interproximal space between the canines and premolarsWhen determining the correct anterior-posterior position a built in bite-block will aid with this. What is one other way to determine the patient is in the right position