Types of x-ray film

 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 follows

1. 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 film

2. 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