test 2 - quizlet

Question 1

purpose of diagnostic imaging?

Answer 1

The primary purpose of diagnostic imaging is to transfer the information from an x-ray beam to the eye-brain neurological system of the interpreting radiologist

Question 2

The ____________ beam aka exit x-ray beam: exits the tube and enters the patient resulting in series of events discussed previously

Answer 2

remnant

Question 3

True or False: Using intensifying screens will allow only 5% film exposure or “blackening” due to direct x-ray-film interaction. This will significantly reduce the patient’s dose

Answer 3

TRUE

Question 4

True/False: After interaction with matter the exit beam reaches the intensifying screens of a cassette. The screen will fluoresce emitting light and exposing (blackening) the film

Answer 4

TRUE

Question 5

In Film design there are 2 basic parts, what are these parts?

Answer 5

base and emulsion

Question 6

True/False: Most films are coated with double emulsion or screen-film

Answer 6

TRUE

Question 7

__________ is the part where the image is formed

Answer 7

emulsion

Question 8

__________ is the part where the image is formed

Emulsion
The history of development of modern film base went from _______ plates to ____________ films to __________ material, which is what we use today

Answer 8

glass plates, cellulose, films, polyester material

Question 9

what does the base provide?

Answer 9

The Base provides rigidity and dimensional stability.

Question 10

emulsion is made of gelatin and contains what crystals?

Answer 10

Silver halide crystals (SHC) 98%-silver bromide with 2% silver iodide

Question 11

When x-rays and light interact via(PE) and Compton with SHC- the initial or ________ image is formed

Answer 11

latent

Question 12

During manufacturing process a part of the emulsion is “contaminated” by silver sulfide which is located in the center or just to the side of the Silver bromide (SHC). This is known as a what?

Answer 12

sensitivity centre or speck

Question 13

True or False: When photons strike the emulsion and SHC, the speck is responsible for attracting and trapping an ion of silver (Ag+) and the electron, producing the latent image

Answer 13

TRUE

Question 14

Modern SHC are _________ in shape which provides for better distribution of coating and more uniform exposure

Answer 14

tabular

Question 15

True/False: Larger crystals will develop faster providing a lower scale of radiographic contrast and smaller crystals will develop slower providing a higher scale of contrast

Answer 15

TRUE

Question 16

When some x-rays and emitted light photons from the intensifying screen interact with SHC it occurs primarily via _______________ and some ____________

Answer 16

photoelectric and some compton

Question 17

what is a secondary electron and what does it do?

Answer 17

secondary electrons are formed from PE and compton x-rays hitting the emulsion and have sufficient energy to dislodge other electrons in the lattice, Thus a single x-ray/light photon is capable of dislodging a number of electrons which migrate to the sensitivity centre of the SHC and become trapped or locked. Once the sensitivity centre captures the photoelectron it attracts interstitial ionic silver (Ag+) and the latent image is formed

Question 18

True or False: In the optimally exposed film most SHC have collected and retain 4-10 silver atoms at their sensitivity centre with the latent image being formed. At this point the Latent image is invisible and It requires to be processed or chemically converted to manifest image or being developed

Answer 18

TRUE

Question 19

__ films are used in dentistry

Answer 19

direct

Question 20

True/False: In mammography, a single intensifying screen is used on the back side and a single emulsion film

Answer 20

TRUE

Question 21

Size and distribution of SHC plays an important role in film __________

Answer 21

contrast

Question 22

________ contrast film’s emulsion contains small SHC with relatively uniform distribution and ________ contrast films contain larger SHC and of less uniform distribution

Answer 22

high

low

Question 23

True or False: Screen-Film is widely used within the image receptor (IR) and is commonly used with the cassette’s intensifying screens.

Answer 23

TRUE

Question 24

Crossover exposure may occur when screen light crosses the base and exposes the opposite emulsion. How can this be avoided?

Answer 24

this is solved by adding a dye or crossover control layer to film base

Question 25

Manual processing- before automatic processing was introduced, manual processing took approximately _________ and started with wetting or soaking of the film then immersing it in the developer, washing it with running water and hanging it to dry

Answer 25

1 hour

Question 26

What is the Automatic processing sequence?

Answer 26

Developing-Fixing-Washing-Drying

Question 27

How long does the automatic processing sequence take?

Answer 27

in 1987 Konica developed automatic processing with 45 sec per step system.

Question 28

What does the developing step in an Automatic processing sequence involve?

Answer 28

electrons are supplied to ionic Ag+ to reduce it to metallic silver: (Ag+ + e- =Ag). The exact chemical composition of the developing agent is closely guarded by the proprietor. The sensitivity centre of the latent image has been exposed or reduced. When developer is introduced it can easily overcome the electrostatic charge(-) on the surface of the silver halide crystal and penetrate it, completing the reduction (exposure) process. Thus reducing ionic Ag+ to metallic Ag or black silver grains seen as exposed parts of the radiographic film. The process is repeated over and over

Question 29

The main components of the developing step in an Automatic processing sequence are ___________ and _____________. Both are reducing agents with high electron content

Answer 29

hydroquinone and phenidone

Question 30

In the developing step in an Automatic processing sequence ___________ acts faster and produces more light shades

Answer 30

phenidone

Question 31

In the developing step in an Automatic processing sequence _______________ acts slowly and is responsible for more dark shades

Answer 31

hydroquinone

Question 32

What does Fixing the film insure?

Answer 32

Fixing-this process ensures archival quality of the film and is added to remove remaining unexposed and underdeveloped SHC from film emulsion

Question 33

what is being used for fixer?

Answer 33

Sodium thiosulfate known as Hypo is being used

Question 34

In the fixing step Acetic acid, known as a(n) ____________ is added to neutralize the pH of the emulsion and stop the developer action. One potential problem is retention of the fixer (Hypo) which continue oxidizing, slowly combining with metallic silver forming Ag2S (Silver Sulfide)

Answer 34

activator

Question 35

What step comes after fixing and why?

Answer 35

Washing is the next step which ensures removal of all fixer so that the film will become of diagnostic and archival quality

Question 36

What solvent is used in the washing step?

Answer 36

H2O is a universal solvent and has been employed during this step

Question 37

What step comes after the washing step and how is it performed?

Answer 37

Drying- warm dry air is blown at the drying chamber

Question 38

An _______________ screen is used in the cassette to intensify the effect of the X-ray photon by producing more light photons by making certain compounds fluoresce

Answer 38

intensifying

Question 39

True or False: The use of Intensifying screens decreases the mAs required to produce a particular density image, thus decrease the amount of patients' radiation dose significantly

Answer 39

TRUE

Question 40

True/False: In cassettes which use double emulsion films, two Intensifying screens are used, mounted on two sides of the cassette and the thickness of an intensifying screen is about 0.4 mm

Answer 40

TRUE

Question 41

True or False: Rare earth elements are used in present day Intensifying screens as they are faster and have higher absorption and conversion efficiency: such as gadolinium, lanthanum, and yttrium

Answer 41

TRUE

Question 42

True/False: Compounds in Intensifying screens need to fluoresce and not Luminesce because Fluorescing will involve a single film exposure where as Luminescing will continue to glow, exposing the film further that is undesirable

Answer 42

TRUE

Question 43

It is important to note that the color of the light emitted (wavelength) from an Intensifying screen must match the light sensitivity of the film used. This is known as ____________ matching

Answer 43

spectral