RAD02 - Lecture 5 - Film-based imaging and Chemical processing

Question 1

What are the 3 speeds of intra-oral radiographic film?

Answer 1

E

D

F

Question 2

What side of the film packet should be facing the X-ray beam?

Answer 2

White surface

(the opposite side will be white + another colour -> picture)

Question 3

What is the contents of a intra-oral radiographic film packet? (4)

Answer 3

Outer wrapper -> white side / coloured side

Plastic film (coated on both sides in green emulsion)

Black paper (either side of film)

Lead foil (thin sheat)

Question 4

What happens to the image if you use the film packet the wrong way round?

Answer 4

Image becomes pale

Question 5

Define chemical (film) processing

Answer 5

Events required to convert the invisible latent image -> visble black/white radiographic image

Question 6

What are the 2 types of chemical processing?

Answer 6

Manual (wet)

Automatic

Question 7

Explain how a film changes after being chemical processed (image)

Answer 7

Question 8

What are the 3 key x-ray set variables on the control panel?

Answer 8

kV - voltage

Time - secconds

mA - current

Question 9

What is the function of Kv (voltage)? (3)

Answer 9

Determines the energy/penetrating power of the photons

This is known as the quality of X-ray beam

This effects the film contrast

Question 10

What is the function of mA (current) and time (secs)? (2)

Answer 10

Determines quantity of X-ray photons

This effets the degree of blackening of film

Question 11

In terms of grading (1,2,3) - what percentagest should dentists target for? (3)

Answer 11

Grade 1 - 70% ≥

Grade 2 - ≤ 20%

Grade 3 - ≤ 10%

Question 12

Identify the exposure/processing error (3)

Answer 12

Too dark

Over-exposed (time set too long/faulty timeer)

Over-developed (temp or concentration too high, develop time too long)

Question 13

Identify the exposure/processing error (3)

Answer 13

Too pale

Under-exposed - time too short, faulty timer

Underdeveloped - temp or concentration (dilute) too low, develop time too short/exuasted

Question 14

Identify the exposure/processing error (3)

Answer 14

This occured during wet processing (as opposed to automatic)

Developer level too low -> no blackening of upper part of film

This leads to it being completely cleared in the fixer

Question 15

Identify the exposure/processing error (1)

Answer 15

Fixer splashes

Question 16

Identify exposure/processing error (1)

Answer 16

Under-fixed

Question 17

What makes it obvious that this “pale film” is not due to under-exposed/developed - and more to do with handling error?

Answer 17

You can see the pattern of the lead foil

This means the film is back to front

Question 18

Identify the cause of handling-error (1)

Answer 18

Exposure to light (fogging)

Question 19

Identify the cause of the handling error

Answer 19

Film bent -> causes pressure to form a dark line

Question 20

Identify the cause of the handling-error (1)

Answer 20

Finger nails damage the film emulsion -> black pressure marks

Question 21

Identify the handling-error

Answer 21

Film used twice -> double exposure

Question 22

Identify the exposure/processing error (1)

Answer 22

Film left in final wash for too long