Week 1: Intro to Radiology and Parallel Technique (w canvas study questions)

The bite-wing image is used in the

Interproximal examination

intra oral X-rays

PA BW occlusal

The images are cleared from the storage phosphor imaging plates by

a clearing step within the scanner.

digital image

a picture in electronic form

Digital imaging uses _________________ to produce an image.

an electronic sensor and computerized imaging system

radiography

art and science of generating and applying x-radiation to film or sensors (receptors) sensitized for the purpose of making shadow pictures (radiographs)

Which of the following is used for an interproximal evaluation?

bite-wing

(1) Given that the human eye can resolve 8 to 10 lp/mm, a CCD system is inadequate for diagnosis of dental disease. (2) The majority of research has shown that the traditional radiographs perform at least as well as digital images and, at times, even better.

both false

(1) The American Dental Association (ADA) and the American Academy of Oral and Maxillofacial Radiology both recommend the use of a beam alignment device to reduce the amount of radiation the patient receives. (2) Limiting the size of the x-ray beam not only reduces the amount of skin that is exposed but also results in a significant reduction of radiation to the patient, by as much as 20%.

both statements false

Vertical angulation

central ray must be directed perpendicular to the receptor and the LAT

Most digital imaging systems use a ______________ as the x-radiation source.

conventional dental x-ray unit

how are radiographs used in dentistry

detect caries root morphology bone/ type of bone loss calculus restorations pathology growth and development

Which of the following would be a reason to switch from film to direct digital imaging?

digital images can be printed when needed

With the feature of _______________, the gray-scale of the diagnostic image is reversed so that radiolucent images appear white and radiopaque images appear black.

digital subtraction

types of intra oral digital imaging

direct digital indirect digital

A sensor with a fiber optic cable linked to the computer is placed into the mouth of the patient and exposed to x-radiation. This is an example of

direct digital imaging

Which basic rule of paralleling indicates that the central ray should be directed through the contact area of the teeth?

horizontal angulation

With digital imaging, the term ___________ is used to describe the pictures that are produced.

image

dental radiograph

images of teeth and related structures produced on receptor or sensor by exposing the receptor to x-rays (x-radiation)

Which technique examines the crowns of both maxillary and mandibular teeth on a single image?

interproximal examination

types of radiographs used in dentistry

intra oral extra oral

The lingual cusp of the first premolar usually obscures the distal contact of the canine on the ________________ exposure.

maxillary canine

Which of the following images must include the crowns, roots, and surrounding bone of the right or left central and lateral incisors?

maxillary incisors

digital radiography

method of capturing a radiographic image using a sensor, breaking it into electronic pieces, and presenting and storing the image on a computer

receptor position

must be positioned parallel to the LAT -receptor is placed as far away to the teeth as possible while keeping the receptor parallel (3/4 to 1 inch)

receptor placement

must be positioned to cover the prescribed area of teeth to be examined

Image magnification occurs when the ______________ distance is increased.

object-receptor

To achieve parallelism between the receptor and the tooth, the ____________ distance must be increased to keep the receptor parallel with the long axis of the tooth.

object-receptor

extra oral X-rays

panoramic cephlametric

Which of the following is an extraoral technique for dental image examination?

panoromic

According to the basic principles of the paralleling technique, the receptor is placed in the mouth _________ to the long axis of the tooth being x-rayed, and the central ray of the x-ray beam is directed ____________ to the receptor and long axis of the tooth.

parallel; perpendicular

Bisecting and paralleling are two methods used for obtaining which of the following dental images?

periapicals

According to the basic rules of paralleling, the central ray should be directed ______________ to the receptor and the long axis of the tooth.

perpendicular

Digital sensors contain distinct units of programmable gray values that are sensitive to x-rays called_____

pixels

analog image

radiographic image produced by conventional film

Which basic rule of paralleling states that the receptor must be parallel to the long axis of the tooth?

receptor position

Image magnification can be decreased when the _______________ is increased.

target-receptor

It is questionable whether digital images can be used as evidence in lawsuits, because

the original digital image can be enhanced

radiology

use of radiant energy (x-radiation) in the diagnosis and treatment of disease

Storage phosphor imaging_______

uses a reusable imaging plate

According to the text, a size 1 receptor is always positioned with the long portion of the receptor in a ____________ direction, and a size 2 receptor is always positioned with the long portion of the receptor in a ______________ direction.

vertical; horizontal

Your patient has no clinical sign of disease; how frequently should you take a CMS on your patient?

you can't take a CMS

Storage phosphor imaging

-A wireless digital imaging system. (A) A reusable imaging plate coated with phosphors is used (B) The phosphor-coated plates record image by converting X-ray energy into light (C) A high-speed laser scanner is used to transfer image to computer

intra oral sensors types

-charged coupled device sensor (CCD) -complementary metal oxide semiconductor/ active pixel sensor (CMOS/APS)

paralleling history

-developed in 1920 by Franklin McCormack -also called right-angle, extension-cone, or long cone technique

what is a pixel?

-electrons produced by X-ray exposure are deposited into a pixel or small box or well -a discrete unit of info -digital info is contained in, and presented as, discrete units of info; also termed picture element

disadvantages of digital imaging vs film

-initial set up cost -image quality -sensor size -infection control -legal issues (images can be manipulated)

advantages of paralleling technique

-it is the preferred method because of minimal distortions of actual tooth dimensions -easy to do

disadvantages of the paralleling technique

-may be uncomfortable for PT -may be difficult to do on a patient with a small mouth or various anatomic features which may present problems

Charged Coupled Device (CCD)

-most common -used in digital camera, fax machines, telescopes -contains a silicon chip with electronic circuit embedded in it -silicon chip is exposed (sensitive) to x-radiation and light -most manufactures use CCD technology in their devices

why was the acceptance of paralleling delayed until the 1960's?

-need for receptor with high speed -need for better machines with higher kilo voltage to produce more penetrating xrays -need for better receptor holders

disadvantages to indirect imaging

-plate artifacts such as scratches -plate longevity -scanning step (more time) -infection control, must be sealed in a barrier -barriers removed using aseptic technique -higher risk of cross contamination. cannot be disinfected

indirect digital imaging

-scanning films, CCD camera scans image, digitizes image and displays on computer monitor -inferior to other types of digital imaging because it is a "copy" of an image, not an "original"

CMOS/APS

-silicon based -differs from CCD in the way pixels are read -lower cost to produce than CCD -DEXIS

advantages of digital imaging vs film

-superior gray scale resolution -reduced exposure to radiation -increased speed of image viewing (direct digital) -lower equipment and receptor cost -increased efficiency -images can be electronically transmitted with HIPPA permission -enhanced image -effective patient tool -protection of environment

occlusal radiographs

-used to locate an object in the buccal/lingual direction -most commonly used in kids (impacted canines)

shadow casting image (film?)

-uses a light source to produce shadows -shadows are produced when light cannot pass through objects -shadows are seen on the ground, floor, etc

creating an X-ray

-uses x-radiation to produce an X-ray image -xray image is produced when x-radiation cannot pass through objects to reach the receptor -xray image is recorded on dental receptor

advantages to indirect imaging

-wireless -flexible -patient comfort

Direct digital imaging

-xray machine, intra oral sensor and computer monitor -sensor captures radiographic image and then transmits image to computer monitor -imaging software

principles or paralleling technique

1) receptor should be parallel to the LAT 2) the central ray is directed perpendicular to receptor and LAT 3) receptor holder must be used to keep receptor parallel to the LAT 4) receptor must be parallel to the LAT to be radiographed

steps on dexis

1) select PT record 2) select template (PAN, BW, PA)

digital imaging steps

1) xray beam strikes sensor 2) electronic charge is produced on surface of sensor 3) electronic signal is digitized (converted into digital form-256 shades of gray) 4) sensor transmits info to computer 5) computer stores incoming electronic signal 6) data acquired by the sensor are communicated to the computer in analog form then converted into digital form by analog-to-digital converter (ADC) 7) software is used to store image electronically 8) image displayed within seconds

5 basic rules of paralleling technique

1. receptor Placement 2. receptor Position 3. Vertical Angulation (central ray of the beam must be directed perpendicular to the image receptor and the long axis of the tooth) 4. Horizontal Angulation 5. receptor exposure

In order to be used for digital imaging, the x-ray unit timer must be adapted to allow exposures in a time frame of _______ of a second.

1/100

Which target-receptor distance should be used in the paralleling technique to compensate for image magnification and loss of definition?

16 inches

how many colors of gray can the digital image use?

256

Periapical images must show the entire crowns and roots of the teeth being examined as well as ____ to ____ mm beyond the root apices.

2;3

How many shades of gray can the human eye distinguish?

32

Your patient is concerned about the amount of x-ray exposure she has had because she had x-rays taken quite often at her previous dental office. You explain to her that the images are necessary and you will be taking digital images which require _________ exposure than the films she previously had taken. Exposure times are ________ than that required for conventional radiography.

50% to 90% less

cone cut

Failure to center the film within the PID

Which of the following receptor holders include aiming rings that aid in the alignment of the position-indicating device (PID) with the receptor?

Rinn XCP instruments

Horizontal angulation

The central ray of the x-ray beam must be directed through the contact areas (inter proximal) between teeth.

(1) A primary advantage to digital imaging is the superior gray-scale resolution that results. (1) Digital imaging uses up to 32 shades of gray.

The first statement is true; the second statement is false.

Your patient has asked why you prefer digital imaging to film. Which of the following reasons would you tell her?

The image appears almost instantaneously for both of us to view.

receptor exposure

The x-ray beam must be centered on the receptor on receptor to ensure that all areas of the receptor are exposed.

Advantages of the use of digital imaging include which of the following?

There is an opportunity for an increase in interactive dialogue between the patient and the radiographer.