lesson 3

Question 1

is the most common image receptor used in conventional radiography. It was the first image receptor chosen by Wilhelm Roentgen when he discovered x-rays in 1895. Even with advancements in digital imaging, x-ray film remains widely used due to

high resolution,
affordability,
and reliability.

Answer 1

X-ray film

Question 2

Manufacturing Process

• Ensures consistency, sensitivity, and durability of the film
• Since x-ray film is light-sensitive, it must be produced and stored in a lightproof environment to prevent accidental exposure.

Answer 2

-Manufactured with vigorous quality control

-Manufactured in total darkness

Question 3

X-ray films are designed to be sensitive to specific wavelengths of light, usually emitted by intensifying screens.

helps match the film with the proper screen, ensuring optimal image quality and minimal radiation exposure.

Answer 3

Spectral Response

Question 4

Film Thickness

Answer 4

175 – 300 μm

Question 5

The thickness of the film influences:

• Thicker films are more durable and less prone to damage.

Answer 5

Handling properties

Question 6

Thinner films may provide finer details but can be more fragile.

Answer 6

Image resolution

Question 7

is an essential component of radiographic imaging, providing high-resolution images through a well-controlled manufacturing process.

Its spectral response and physical properties are carefully designed to ensure optimal performance and diagnostic accuracy.

Answer 7

X-ray film

Question 8

FILM CONSTRUCTION.

Answer 8

Super coat/overcoat/ protective layer
emulsion/ the active layer
adhesive/ substratum coating
base/structural support

Question 9

is a multi-layered structure designed for high-quality imaging, durability, and efficient processing.

Each layer-supercoat, emulsion, adhesive layer, and base plays a vital role in ensuring that x-ray films produce sharp, detailed, and long-lasting images.

Answer 9

Radiographic film

Question 10

is the outermost layer of a radiographic film. It is made of a thin, hard gelatin covering that encloses and protects the emulsion layer beneath it.

Answer 10

The supercoat (also called the overcoat or protective layer)

Question 11

Purpose & Function of supercoat

Answer 11

1. Protects the emulsion from damage
2. Allows rough handling before exposure
3. Prevents physical and chemical damage to the emulsion caused by:

Question 12

Characteristics of supercoat

Answer 12

Antistatic properties
Extremely strong and durable
Difficult to tear

Question 13

Thickness of supercoat

Answer 13

2-5 µm (micrometers)

Question 14

plays a critical role in ensuring the durability and longevity of radiographic films by protecting the delicate emulsion from physical and chemical damage.

This allows for reliable image quality while ensuring that the film withstands handling, storage, and processing conditions.

Answer 14

The supercoat layer

Question 15

is the core component of radiographic film, responsible for capturing the latent image during exposure to x-rays or light.

This layer’s composition and structure are pivotal in determining the film’s sensitivity, contrast, and resolution

Answer 15

emulsion layer

Question 16

Composition of emulsion layer

Answer 16

Gelatin
Silver Halide Crystals

Question 17

Serves as a suspension medium for silver halide crystals, ensuring their even distribution.

is clear, allowing unobstructed passage of light, and porous, permitting processing chemicals to reach the crystals during development. Its flexibility ensures the film can bend without image distortion.

Answer 17

Gelatin:

Question 18

These are the photosensitive agents within the emulsion. Upon exposure to radiation, they undergo chemical changes, forming the latent image.

Answer 18

Silver Halide Crystals:

Question 19

The crystals are typically composed of

Answer 19

silver bromide (AgBr) and silver iodide (AgI), with modern emulsions containing approximately 95-98% silver bromide and 2-5% silver iodide.

The size and shape of these crystals influence the film’s speed and image quality.

Question 20

The emulsion layer’s thickness

Answer 20

it ranges between 5 to 10 micrometers (um).

Question 21

Types of Emulsion Films

Answer 21

Single Emulsion Film
Double Emulsion Film

Question 22

• Coating: Emulsion is applied to one side of the film base.

Design: Intended for use with a single intensifying screen.

Identification: Features an identifying notch, typically in the lower left corner, to distinguish the emulsion side.

• Appearance: The emulsion side appears dull, while the non-emulsion side is shiny.

• Applications: Commonly used in duplication, mammography, and fine-detail extremity imaging, where high image detail is paramount.

Answer 22

Single Emulsion Film

Question 23

Coating: Emulsion layers are applied to both sides of the film base.

Design: Engineered to enhance imaging speed, effectively doubling the sensitivity compared to single emulsion films.

Processing: Remains flat after processing, ensuring ease of handling and consistency.

• Applications: Widely utilized in general radiography, especially for extremity examinations, due to its balanced sensitivity and image quality.

Answer 23

Double Emulsion Film

Question 24

Composition of Emulsion

• is not merely a passive medium; it plays several critical roles:

Mechanical Support: Holds silver halide crystals uniformly in place, preventing clumping and ensuring consistent image quality.

Chemical Permeability: Its porous nature allows developer and fixer solutions to penetrate and interact with the silver halide crystals during processing.

Optical Clarity: Being transparent, permits light to pass through without distortion, essential for accurate image reproduction, integrity.

Flexibility: Enables the film to withstand bending and handling without compromising the emulsion’s integrity

Answer 24

Gelatin

Question 25

Size and Shape: Typically around 1 micrometer (um) in size, these crystals can be tabular (flat and triangular), cubic, octahedral, or polyhedral. The shape and size influence the film's sensitivity and resolution. Chemical Composition: Modern radiographic films predominantly use silver bromide, constituting about 95-98% of the crystal composition, with silver iodide making up the remaining 2-5%. Electrical Properties: Crystals possess a negatively charged surface due to the presence of halide ions (Bromide and Iodide), while the interior is positively charged (Silver).

Answer 25

Silver Halide Crystals

Question 26

Intentional imperfections, often introduced using silver sulfide, act as sites where latent image formation begins by attracting free silver ions during exposure.

Answer 26

Sensitivity Specks

Question 27

pivotal in capturing high-quality radiographic images. Understanding its components and their functions provides insight into the film's behavior during exposure and processing, ultimately influencing diagnostic accuracy.

Answer 27

emulsion layer's

Question 28

also known as the substratum or subbing layer, is a vital component of radiographic film, situated between the emulsion and the base. This thin coating serves several essential purposes:

Answer 28

adhesive layer

Question 29

The adhesive layer maintains a firm bond between the emulsion and the base, ensuring they remain in proper contact during handling and processing. This bond is crucial for preserving the film's structural integrity and preventing issues such as separation or peeling of the emulsion from the base

Answer 29

Ensuring Proper Contact and Integrity

Question 30

By securely attaching the emulsion to the base, the adhesive layer helps prevent the formation of bubbles or other distortions that could occur when the film is bent during handling or processing. This stability is particularly important when the film is wet and subjected to the heat of development processes.

Answer 30

Preventing Distortions

Question 31

is indispensable for maintaining the cohesion and functionality of radiographic film, ensuring that the emulsion and base work together seamlessly to produce clear and accurate images.

Answer 31

adhesive layer

Question 32

serves as its foundational support, providing a stable structure onto which the emulsion layer is coated. Over time, the materials used for the film base have evolved to enhance image quality, safety, and durability.

Answer 32

Base

Question 33

In the early days of radiography, used as the base material. While they offered excellent dimensional stability, their fragility and weight posed significant challenges.

Answer 33

Glass Plates

Question 34

Introduced in the 1920s, replaced glass plates. Despite being lighter and more flexible, it was highly flammable, leading to safety concerns.

Answer 34

Cellulose Nitrate

Question 35

In the mid-1920s, emerged as a safer alternative to cellulose nitrate. It retained flexibility and was less flammable but lacked optimal dimensional stability.

Answer 35

Cellulose Triacetate

Question 36

Since the 1960s, has been the preferred material for radiographic film bases. It offers superior strength, flexibility, and dimensional stability, ensuring consistent image quality and ease of handling.

Answer 36

Polyester

Question 37

Thickness: Typically ranges from 150 to 300 micrometers (µm), providing a balance between durability Dimensional Stability: Maintains consistent size and shape during exposure to processing chemicals and varying temperatures, preventing image distortion. Transparency and Tint: The base is uniformly transparent and often tinted with a blue dye. This tint reduces eye strain for radiologists, enhancing diagnostic efficiency and accuracy. Coating: A special light-absorbing dye is applied to the base to prevent crossover effects, which can degrade image quality

Answer 37

Key Characteristics of the Polyester Film Base: