The Production Of Radiographic Image

Question 1

What are the 3 types of x-ray imaging?

Answer 1

Conventional radiography
Digital radiography
Computed radiography

Question 2

Screens and phosphor crystals

Answer 2

X-ray excites crystal to emit light —> light exposes film —> more efficient and less radiation

Question 3

Cassette

Answer 3

2 screens inside the cassette with film sandwiched between
Light produced from phosphor crystals embedded in each screen and light exposes the film from both screens

Question 4

Fast screens

Answer 4

Large crystal size
Lower exposure (low mAs, short time)
Sacrifice detail (light is more diffuse)

Question 5

Par speed (screen)

Answer 5

Average sized crystals
Average exposure and detail

Question 6

Detail screens

Answer 6

Smallest crystal size
Highest exposure
Longer mAs
Greatest detail (light is less diffuse)

Question 7

Characteristics of a good quality radiograph

Answer 7

Area of interest is on film
Proper positioning
Good contrast (fat helps)
Good detail
No film artifacts

Question 8

High contrast

Answer 8

Short scale
Fewer shades of gray with greater difference between steps
Lower kVp
the image you want

Question 9

Low contrast

Answer 9

Long scale
More shades of grey with less difference between steps
Higher kVp
good for thorax

Question 10

Technical errors (causing poor image detail)

Answer 10

Low max: not enough rays
Motion: blurry (long exposure time)
Large patient size (scatter radiation)

Question 11

Pathology in patient (causes of poor image detail)

Answer 11

Excess fluid in body cavity
Lack of normal fat to distinguish between abdominal structures

Question 12

Overexposure

Answer 12

Image too dark
Caused by too high kVp or mAs
(Decease kVp first)

Question 13

Underexposure

Answer 13

Image too light
Caused by too low kVp or too low mAs

Question 14

Digital radiography

Answer 14

Digital ray sensors are used instead of traditional photographic film (replaced by detector device)
Processor, view boxes, data server and grids used

Question 15

Advantages of DR

Answer 15

Time efficiency
Less radiation can be used to produce an image
Immediate image preview availability
Wider dynamic range

Question 16

How does DR work?

Answer 16

Incident ray energy converted into light by a scintillator —> emoted light bundled by an optical lens to fit size of charge-coupled device detector —> converts light into electrical charges

Question 17

Detector pads in DR

Answer 17

Charged-couple devices (CCDs)
Flat panel detectors (portable DR system)

Question 18

Computed radiography

Answer 18

Similar to conventional, except in the place of a film to create the image, the imaging plate made of photostimulable phosphor

Question 19

How is the imaging plate used?

Answer 19

How in a special cassette and placed under the body part or object to be examined, and the x-ray exposure is made
The IP is processed using a CR reader to generate a digital image and displayed on a computer monitor

Question 20

How is CR used?

Answer 20

IP absorbs the energy from the rays, trapped in high energy electrons to create a stored image —> the image in the IP scanned in a CR reader using a laser beam and the traps electrons emit light photons —> light photons converted to additional signal by the photo multiplier tube —> then transferred to a computer for processing and display on a computer monitor

Question 21

Digital imaging: commonalities

Answer 21

No radiographic film used
Signal from imaging plate for CR and sensor pad for DR sent to a computer for storage and display
Storage of data: picture, archiving, and communication system (PACS)