3. Image Receptors & Processing

Question 1

Overview of image processing:

Answer 1

1. Emittion of x-ray photons
2. differential absorption
3. differential exposure
4. latent image is produced
5. processing (chemical or digital)

Question 2

Types of image receptors for xrays

Answer 2

1. non-digital e.g. film
2. digital-indirect e.g. PSP plates
3. digital-direct e.g. CCD/CMOS sensors

Question 3

Components of an xray film packet.

Answer 3

1. film
2. black paper on both sides of film
3. lead foil

Question 4

What is the purpose of the black paper?

Answer 4

prevents light penetration

Question 5

What is the purpose of the lead foil?

Answer 5

1. Shields film from backscatter radiation
   - which creates fog & reduces contrast
2. reduces px exposure by absorbing residual xray beam

Question 6

Components of an xray film?

Answer 6

layers:
1. base - provides support
2. emulsion - active layer of silver halide crystals
3. overcoat - provides protection

Question 7

what are the 2 grain types that emulsion exists as?

Answer 7

1. globular grain
   - rounder crystals
   - ‘ultra-speed film’/d-speed
2. tabular grain
   - crystals are narrower, more cross sectional area
   - ‘insight film’/F-speed
   - less radiation required
   - thus, processes faster