Digital and Film Radiography 1

Question 1

What are the two types of x-ray receptors?

Answer 1

Digital (phosphor plate, solid-state sensor- ALL MULTIPLE USE)

Film (direct action film, indirect action film- ALL SINGLE USE).

Question 2

What is a size 0 phosphor plate used for?

Answer 2

Anterior periapicals.

Question 3

What is a size 2 phosphor plate used for?

Answer 3

Bitewings and posterior periapicals.

Question 4

What is a size 4 phosphor plate used for?

Answer 4

Occlusal radiographs.

Question 5

What is an xray shadow?

Answer 5

When the xray beam passes through an object some of the xray photons are attenuated creating an xray shadow. This shadow is basically the image information held by the xray photons after an xray has passed through an object. The image receptor detects this xray shadow and uses it to create an image.

Question 6

How does an xray shadow of a ball created?

Answer 6

Square cross section xray beam
Attenuation at edge of ball and gets more significant in the middle as more attenuation- xray beam passes through max diameter of the ball- more absorption and scatter of xray photons

The receptor measures the xray intensity at defined areas (arranged in a grid)
Each area is given a value related to xray intensity
Each value corresponds to a different shade of grey 0= black, 255= white. The digital image is displayed as a grid of squares called pixels. Each pixel can only display one colour at a time. The more pixels you have, the more detailed your image can be.

Question 7

What is the maximum and minimum value of xray intensity?

Answer 7

0-255.

Question 8

What does the higher number of pixels in an image mean?

Answer 8

Better detail and higher resolution. Increasing the resolution will provide a more diagnostic image up to a limit (eventually it will not provide any meaningful clinical benefit).

Question 9

Why do we not use the highest pixel size we can get?

Answer 9

Although it may produce a more sharper image, increased pixel size increases the file size (takes up more space and more expensive). The image might not be clearer but we need it good enough to be able to diagnose from. More pixels are harder to manufacture too.

Question 10

How many binary digits does a greyscale bit depth have?

Answer 10

8 (256 shades of grey).

Question 11

What does a higher bit depth mean?

Answer 11

More shades of grey and therefore a more accurate image.

Question 12

Look at this lecture (as i cant copy and paste photos) and see the negative, contract, emboss and magnify images of an xray.

Answer 12

.

Question 13

What does DICOM stand for?

Answer 13

Digital imaging and communications in medicine/

Question 14

What is DICOM?

Answer 14

International standard format for handling digital medical images (used to transmit, store, retrieve, print, process and display images). it allows imaging to work between different software, machines, manufacturers, hospitals and countries without compatibility issues. You can store more information next to the xray image too.

Question 15

What does PAC stand for?

Answer 15

Picture archiving and communication system.

Question 16

What is PACS?

Answer 16

A medical imaging technology which provides storage and access to images (typically in a healthcare organisation). This is in Scotland. It is a secure network for the transmission of patient information and archives for the storage and retrieval of images and reports.

Question 17

What two things do you need to consider when viewing digital radiographs?

Answer 17

ENVIRONMENT (subdued lighting and avoid glare)

MONITOR (clean, adequate display resolution, high enough brightness level and suitable contrast level).

Question 18

What does SMPTE stand for?

Answer 18

Society of motion picture and television engineers.

Question 19

What is SMPTE test pattern?

Answer 19

It can be used to assess the resolution, contrast and brightness of your monitor/monitors.

Question 20

What are the two types of digital (intra-oral) receptors?

Answer 20

Sold state sensors

Phosphor plates.

Question 21

What are the other common names for phosphor plates?

Answer 21

Photostimulable phosphor plates and storage phosphor plates.

Question 22

What are the 5 stages of image creation using phosphor plates?

Answer 22

within the patients mouth

1. the receptor is exposed to an xray beam
2. phosphor crystals in receptor excited by the xray energy resulting in the creation of a latent image

within the scanner

3. receptor scanned by a laser
4. the laser energy causes the excited phosphor crystals to emit visible light
5. this light is detected and creates the digital image.

Question 23

What are the two different types of solid state sensors?

Answer 23

CCD (charge-coupled device)

CMOS (complimentary metal oxide semiconductor).

Question 24

What is a solid-state sensor?

Answer 24

It is connected to a computer and the latent image is created and is immediately read within the sensor itself (final image converted visually instantly).

Question 25

What are the different components of a solid-state sensor?

Answer 25

BACK HOUSING AND CABLE

ELECTRONITE SUBSTRATE

CMOS IMAGING CHIP

FIBRE-OPTIC FACE PLATE

SCINTILLATOR SCREEN

FRONT HOUSING.

Question 26

What are the disadvantages of a solid-state sensor?

Answer 26

Bulky and more expensive to make.

Question 27

What is an identification dot?

Answer 27

It is located in the corner of the receptor to aid orientation of the image. It is only effective if the receptor was positioned correctly during the procedure. Makes sure you are not mixing left and right side.

Question 28

How is cross infection controlled in relation to the receptors?

Answer 28

Intra oral receptors have purpose made covers to prevent saliva contamination (single use covers)
RECEPTORS ARE ALWAYS CLEANED AFTER USE.

Question 29

What are the examples of single use covers used in cross-infection of receptors?

Answer 29

Adhesive sealed plastic covers (for PP)

Long plastic sleeves (for wired SSSs).

Question 30

Where is the most appropriate place to hold a receptor?

Answer 30

By their edges and not by their flat surfaces.

Question 31

What are the advantages of phosphor plates vs solid-state sensors?

Answer 31

Phosphor plates are thinner, lighter and usually flexible. They are wireless and more stable and comfortable. They have variable light room sensitivity which creates the risk of impaired image. The latent image needs to be processed in a scanner separately

Solid-state sensors are bulkier and rigid. They are usually wired and have a smaller active area (for same physical area of receptor). There is no issues with room-light control. They are arguably more durable and replaced less often but are more expensive.