x-ray film cassette
A cassette is a hard holder that is used to hold the screen and the film. It is a light tight device that cannot enter the light in it. The main purpose of the cassette is to protect the film from exposure to light and protect the film from any Also type of banding or rubbing, avoid scratches.structure
The cassette has 2 parts, the front or front part and the back part. The front part is towards the x ray tube and is made of material of low / low atomic number so that x rays easily expose the x ray film passing through that part. And the back part of the cassette is made of material with high atomic number, usually the lead (pb) is chosen for this. Which acts to absorb radiation and provides protection to the patient from scattered radiation.
The front part of the cassette has a front intensifying screen and the back part has a back intensifying screen. xray film is loaded between the front intensifying screen and the back intensifying screen. The loading and unloading of the film in the cassette must be done inside the dark room.Note-:
The back part of the cassette has clips and hinges which make the cassette anti-light and sometimes these clips cause an X-ray back scatter to bring an art effect to the films but such a high Kelovoltage occurs in radiography.
Never, cassette should be opened in white light and day light as it spoils the x-ray film.
2. During the work in the radiology department, rough handling of the cassette should not be done so that there is no possibility of any scratch or other malfunction in the cassette.
3. The hinge and clip on the backside of the cassette should be checked periodically, if these clips have deteriorated, they should be repaired at the right time or there is a possibility of light and radiation reaching inside the cassette so that the films The
cassette should be kept away from the developer and fixer solution while working in the dark room, otherwise these solution spots may fall on the
cassette 5. The cassette should be periodically cleaned by a cotton pad to prevent dust. Etc. The particles cannot reach inside the cassette. 6. Cassette
should be kept length-wise as per their size, such as books are kept in the cupboard. If the cassette is kept one on top, then pressure comes on the films, which is static on the film. There is a possibility of artifact
7. When the cassette is open during work in the dark room, then the radiographer working in the dark room should speak at least and in case of sneezing, the cassette should be closed immediately, otherwise the saliva emanating from the mouth Drops can cause spots on the screen present in the cassettes, which can also cause artifacts on films.
8. Sterilization / disinfection of cassettes should be done from time to time as it keeps in contact with the patient with very serious and infected diseases.
The back part of the cassette has clips and hinges which make the cassette anti-light and sometimes these clips cause an X-ray back scatter to bring an art effect to the films but such a high Kelovoltage occurs in radiography.
Care / handling of cassette -:
The cassette is a very important device in the radiology department as it provides an anti-light and radiation environment to the film, so that to a large extent the quality of the image in the radiology department can be avoided, so the cassettes need some special precautions. Which is as follows 1.Never, cassette should be opened in white light and day light as it spoils the x-ray film.
2. During the work in the radiology department, rough handling of the cassette should not be done so that there is no possibility of any scratch or other malfunction in the cassette.
3. The hinge and clip on the backside of the cassette should be checked periodically, if these clips have deteriorated, they should be repaired at the right time or there is a possibility of light and radiation reaching inside the cassette so that the films The
cassette should be kept away from the developer and fixer solution while working in the dark room, otherwise these solution spots may fall on the
cassette 5. The cassette should be periodically cleaned by a cotton pad to prevent dust. Etc. The particles cannot reach inside the cassette. 6. Cassette
should be kept length-wise as per their size, such as books are kept in the cupboard. If the cassette is kept one on top, then pressure comes on the films, which is static on the film. There is a possibility of artifact
7. When the cassette is open during work in the dark room, then the radiographer working in the dark room should speak at least and in case of sneezing, the cassette should be closed immediately, otherwise the saliva emanating from the mouth Drops can cause spots on the screen present in the cassettes, which can also cause artifacts on films.
8. Sterilization / disinfection of cassettes should be done from time to time as it keeps in contact with the patient with very serious and infected diseases.
Cleaning of cassette-:
There are two screens inside the cassette, the screen should never be scratched and there should be no chemical support as it will cause the shadow to appear while exposing the xray film. Therefore, the screen should be checked periodically and the cassette end screen should be cleaned from time to time. It is necessary to clean the cassette end screen every 6 months, for this, document the cleaning date.Process of cleaning: -
To clean the cassette end screen, bring all the cassettes inside the dark room and close the door of the dark room, turn on the safe light and open the cassette and take out the film. According to the film, put the box in the box, then take the cassette out of the dark room and place the cassette on a clean and dry table, clean the cassette with soap solution with the help of cloth, after that dry the cassette and screen with a good cloth. Cleans in a way that removes all moisturizers. And the cassette dries well. The cassette is kept in open or open condition on a dry batch inside the dark room until completely dry, which is away from the dust. The cassette is loaded back when it is thoroughly dry. It is necessary to clean the cassette in 6 months
Characteristics Of X-Ray Film
1. Density-:
Density refers to the darkness above the film, the greater the darkness of the film, the greater the density of the film. The density depends on the exposure, the higher the density received by the radiation film in the amount, the higher the density will be on the film. Measuring the blackness of a film is called optical density.Which is defined by the following figure.0.25–2.0 optical density is commonly used inside radiology.
The density of the film depends on the following.
A. Quantity of x-ray beam-:
Quantity of a beam is the number of xray photons. Increasing the value of current / current inside the x ray tube will also increase the production of electrons, which will also increase the number of xray photons. And the density of the film will also increase. Due to which the patient dose will also be more. Therefore, the density will also increase as the beam's volume increases.
B. The quality of x-ray beam
expresses the penetrating power of the X-ray beam. If you increase the Kv, a greater amount of tissue will penetrate the xrays and reach the film, which will make the film darker. And the density of the film will also increase. Hence, the density will also increase with increasing the quality of the xray beam.
A. Quantity of x-ray beam-:
Quantity of a beam is the number of xray photons. Increasing the value of current / current inside the x ray tube will also increase the production of electrons, which will also increase the number of xray photons. And the density of the film will also increase. Due to which the patient dose will also be more. Therefore, the density will also increase as the beam's volume increases.
B. The quality of x-ray beam
expresses the penetrating power of the X-ray beam. If you increase the Kv, a greater amount of tissue will penetrate the xrays and reach the film, which will make the film darker. And the density of the film will also increase. Hence, the density will also increase with increasing the quality of the xray beam.
2. Object density
If the density of the object is high, then the density of the film will be less. Because the density or thickness of the patient will be higher, the absorption of xray will be higher, which will lead to fewer xrays reaching the film. Due to which the blackness on the film will also be reduced.3. Film fog
Density is reduced due to film fog. Which can be produced due to improper safe light.4. Exposure
Density also increases along with exposure.
Types of x-ray film
Xray films are transparent films made of emulsions that are active against light photons and also sensitive to radiation. xray films are classified in many ways. Which is as follows1. dental film - :
It is of two types -
A. Intra oral dental film -:
This type of film is exposed by placing it inside the patient's mouth. And it is a double emulsion film. And it is exposed without screen. In this type of films, only a maximum of 3-4 teeth at a time is possible for xray. This type of film is wrapped in the backing of lead (pb) coated so that the patient feels less radiation dose.B. extra oral dental film(panoramic)
This type of film is exposed in the patient by keeping it out of the mouth. And it is a single emulsion film. These types of films are also called panoramic films. Because in this one time exposure, the entire 32 teeth xray is done. And has long exposure or penaromic exposure. exa- OPG (orthopantomagram)2. Mammography film
It is a single emulsion film on the principle of fine grain, ie this type of film has only one layer of emulsion. Also known as a single-coated film. This type of film is used with single intensifying screen.3.duplicating film
It is a single emulsion film. In this, any type of film is copied by ultraviolet light or by normal light. The size of the duplicating film should be equal to the one being copied.4. substraction film
This type of film is used in angiography. It is a single emulsion film, high quality contrast is achieved in these types of films.5. Medical imaging film
This type of film is used in CT scan (computerized demography scan), MRI (magnetic resonance imaging), digital radiography, PET screen (positron emission tomography) etc.Medical imaging films are single layer coated films of five layers
A. Base -:
It is made of polyester with blue tinge. And it is transparent. And it is non-folding and non-breaking, with long-term safeguarding properties. This property of the base is called dimensional stability.
B. Substratum :-
This layer serves to affix the base to the emulsion. Meaning it performs the function of adhasive.C. emulsion :-
It is located on the front side of the medical imaging film. Which contains a mixture of gelatin and particles of silver halide. Which makes the film light sensitive.D. Top coat -:
It is made of gelatin and hardener material which provides protection to the emulsion from scratches or external shocks.E. Anti halo layer: -
In this medical imaging film, it is the back layer that protects the film from halation. And provides a blur-less sharp image. In the absence of this layer, the radiation exposure may reflect off the emulsion layer, causing the film to double expose, which is called halation.Classification of films by screen
1. Screen film ( indirect exposure film )
This type of film is mostly used in radiography. Intensifying screen is used with this type of film. The intensifying screen photo on this type of film creates a latent image with an electric effect. There are many types of light sensitive film available in this category. Example - mammographic film2. Direct exposure / non screen film -:
The emulsion of this type of film is thicker than that of a screen film. And their exposure is done by direct xray. Non-screen film is expose by placing it in a cardboard / cardboard holder. Meaning is used without an intensifying screen. And it is four times faster than normal speed film. So generally a quarter of exposures are required for good contrast and blackening. This type of film is used in factories.Types of Films based on Light Sensitive Emulsion Coating -
1.blue light sensitive film
2. Green light sensitive orthochromatic films
3. Red light sensitive panchromatic films
Types of films based on film speed -
1. Standard or pan speed film
2.fast speed films
3.ultra fast speed film
xray film
X-ray film is a medium used to record the image of an exposed body part for x ray. This film is generally similar to photographic film. The difference in radiographic film is that one side or both of it is radiosensitive or light sensitive. The emulsion material is coated or coated so that it can be used with the intensifying screen by exposing it on top of this radiographic film and creating a latent image And later, by processing it, the latent image is converted into a visible image. The structure of the radiographic film is as follows
Structure of x ray film
Often the film is produced from a lower layer or layer which is as follows -
1.base layer
It is the central or central part of the x ray film that supports the photographic emulsion layer from both sides.
This base part should be non-folding and non-breaking. It should be able to bear any type of geometric distortion (temperature, pressure) so that it can be processed.The base provides a transparent, uniform visual background to the film.
First the x ray film plate consisted of an emulsion layer on both sides of a glass base. But during the First World War, belzium shut down its supply of photographic glass. Then the demand for xray film base started coming up all over the world.
In 1914, cellulose triacetate was first used as a film base. And by 1924 completely cellulose tri acetate was used for the base.Cellulose tri acetate is a flammable material. Hence polyester base was manufactured in the 1960s and polyester base is also used at present. The dimensional stability of the polyester base is very good. The film base is a transparent material. Blue tint was given inside the film base for the first time in 1933 to reduce the fatigue of the radiographer's eyes. Blue tint is also currently used.The thickness of the CTA (cellulose tri acitate) base is 8 miles and the thickness of the polyester base is 7 miles. Which is 0.01 inch = 1 mile.
2.adhesive layer
Most emulsion layers do not attach easily to the base layer. Hence, its main function is to glue two layers together. That persist between the emulsion and the base layer.
3. Emulsion layer
This is the most active layer of the Xray film. Which are located between the protective layer and the adhesive layer. Radiographic images are produced on this layer. This layer mainly consists of two components.
A. Gelatin medium
B. Silver halide crystal (grain)
Which are found as particles in the silver halide gelatin medium. Apart from these, other chemical substances such as weighting agent, centicogluent, and hardner are also added to the emulsion.In order to obtain a good quality image on the film, 90–99% silver bromide (AgBr) and 1–10% silver iodide (AgI) are found in the silver halide crystals. The emulsion is the part of the xray film on which xray photons work and produce the image. For this, the emulsion must be cleaned so that the xray photon can easily enter the emulsion. And the processing solution can easily enter the emulsion evenly. The silver halide crystals have a thickness of 0.1 –1.5 micrometers.
Property of emulsion
To increase the quality of the radiograph, the emulsion of the film should have the following qualities
A. Speed / sensitivity -: Speed or sensitivity emulsion has the ability to react with xray, ie when the emulsion is able to provide good density and good contrast to the film at very low exposure, then this type of emulsion is called fast or high speed emulsion. is. Normal films are fast films.
B. Latitude -: Latitude has the ability to show contrast of radiographic images of emulsions over a long scale from white to black with a long range of Tons. The letitude of the emulsion should be high so that the mistakes in the exposure have the least impact on the image of the film.
4. protective layer
During the film handling, a protective layer is used to protect the emulsion part from scratching and damage. These layers are also made of gelatin.
Entry Type / Darkroom Door
The darkroom is an important location in the radiology department where the x-ray film taken is processed. This room lacks illumination compared to normal rooms. The purpose of keeping dark in this room is to process photosensitive photographic materials.
Entrance
The door of this room is light tight, that is, it is made in such a way that rays of light could not enter it. The door has a locking system so that other people do not enter the room during film processing.
There are four types of darkroom depending on entrance / entry.
1. revolving door
It is the most expensive type of the most efficient type of door. It is made up of two cylinders. The outer cylinder is fixed and the inner part is a curved door with only one opening.
2. Single door
This is the most simple and inexpensive type of door. Due to this door's left descent being open, light rays directly enter the dark room. In this type of round system, locking mechanism is used. When the film bin is open in the darkroom or the film is being processed, the door remains locked / closed.
3. Double door system
This type of dark room has two doors, one door opens to the outside and one opens inward. There is a hallway between the two doors. In this pattern, one door opens only when the other door is closed.
4. Maze type door
In this type of entrance, there is no door, a labyrinth like a labyrinth leads to Darkroom, for this more space is required, it is also called labyrinth entrance.
