General information
An X-ray cassette is a light-resistant flat container used to hold an X-ray film in close contact with an intensifying screen.
Part of advanced screen film systems.
The advanced screen-film system "the green system" uses green-emitting screens and green-sensitive (orthochromatic) film. It has twice the speed of the "blue system", in the upper kV-range, and provides better image resolution.
Specifications
CASSETTE / INTENSIFYING SCREENS
An X-ray cassette is a light-resistant container that protects the film from exposure to daylight, holds the film between two intensifying screens and allows the passage of X-rays through the front cover on to the film.
When stroked by radiation the intensifying screen fluoresces emitting a light that creates the image on the X-ray film.
X-ray cassettes have a multilayer layers.
|
Cassette top, plastic:
X-ray tube side |
1 layer: steel foil
1 layer: space for the 1st intensifying screens |
|
|
1 layer: space for X-ray film |
|
|
1 layer: space for 2nd intensifying screens |
|
|
1 layer: magnetic sheet |
|
Cassette bottom, plastic: |
Patient side |
|
Specifications: |
Cassette container |
|
Materials: |
Metallic or though light plastic (Novadur) |
Rounded edges, long-lasting, shockproof, light-proof.
Plastic cassettes are 25-30% lighter than the metallic ones.
Easy to load and unload: minimum recommended opening 180°.
A countersunk relief dot clearly indicates whether or not the cassette is loaded with a film.
- Intensifying screen: GREEN
An intensifying screen is a thin sheet of cardboard, celluloid or plastic that is placed in contact with the X-ray film in a cassette; it is commonly used in pairs, one on either side of the film.
The gadolinium-oxysulphide screen emits groupings of green lights at different speeds.
The cassette is placed in a grid holder. which can be mobile (on a mobile X-ray examination table or in an x-ray chest stand) or fixed (on a Bucky table with a fixed X-ray unit).
The recommended speed is 400 and must be written on the cassette.
Intensifying screens should not be ordered individually, as the size varies slightly according to brand. Always indicate the brand name and manufacturing date, if possible. Otherwise, a complete new cassette will be sent.
- Film indicator: On empty cassettes, a countersunk relief dot can be clearly seen and felt.
When the cassette is loaded, the dot fills.
Cassette sizes and uses:
|
|
Cassette size |
Intensifying screen speed |
Intended use |
|
Width |
Length |
|
XXRACASG1824 |
18 |
24 |
400 |
- Vertebrae, cervical
- Shoulder joint
- Clavicle
- Wrist, hand
- Knee joint
- Ankle joint
- Toes or forefoot |
|
XXRACASG1843 |
18 |
43 |
400 |
- Vertebrae thoracic, lumbar
- Humerus, forearm
- Femur, lower leg |
|
XXRACASG2430 |
24 |
30 |
400 |
- Skull
- Vertebrae lumbar (child)
- Sacrum and coccyx
- Hand
- Neck of the femur
- Knee joint
- Metatarsals |
|
XXRACASG3040 |
30 |
40 |
400 |
- Chest |
|
XXRACASG3543 |
35 |
43 |
400 |
- Vertebrae thoracic
- Vertebrae lumbar
- Femur with hip joint
- Lower leg with knee or ankle joint
- Abdomen |
.
|
Unit presentation: |
1 cassette, marked with size, type of screen, speed, and manufacturing date. |
|
Packaging: |
The following information should appear on the outside packaging: |
|
|
Designation of item, type of screen and speed.
- Manufacturer’s name and address.
- Must be multilingual: English, French and Spanish, others when available. |
|
|
- CE mark and reference number of notifying body. |
|
Other: |
Conforming to Medical Device Directive Council Directive 93/42/EEC complies with EN ISO 4090: 2004-08/ AINSI PH1.49: Photography - Medical radiographic cassettes/screens/films and hard-copy imaging films - Dimensions and specifications (ISO 4090:2001) |
NOTE:
Depending on the country, the blue system may still be in use; reorder cassettes and films accordingly.
The blue-screen film system is being progressively replaced with the newer more advanced green system because patient radiation exposure time is 2 times shorter.
Whenever possible, where the X-ray generator is below 23kW, the advanced screen film system should be prompted.
Reminder: Basic screen film systems are based on blue-emitting calcium tungstate screens, and use blue-sensitive X-ray films.