The intensifying screens convert the x-ray radiation into visible light creating the image on the film. X-ray film is actually much more sensitive to visible light. The x-ray film by itself is relatively insensitive to x-rays and takes a substantial number of x-rays to expose the film. A common cause of poor film-screen contact is warping of the cassette from dropping or other rough handling. Any increase in the screen-film separation distance allows the light from the screen to spread, resulting in exposure of film that is undesired. Any increase in the distance between the screen and the film results in blurring of the image and degradation in image contrast. When the cassette is closed a tight contact is created between the screens and the film, it is very important that this contact be maintained. The film is then placed between the screens. The screens are mounted to the inside front and inside back of the cassette with adhesive. The cassette holds a piece of double-emulsion x-ray film sandwiched between two fluorescent sheets of plastic called intensifying screens.
Radiographs are formed with light sensitive film contained in a lightproof encacasement, or cassette. To further understand radiography it is important to understand how a permanent record is produced using x-rays.
In previous session we have discussed how x-rays are produced in the Physics of Radiology and how that affects radiography quality in Choosing the Appropriate Exposure Factors. Course 2 – Choosing the Appropriate Exposure FactorsĬourse 4 – Poor Quality Films-Causes and CorrectionsĬourse 5 – Radiation Safety-Importance and ProceduresĬourse 6 – Pros and Cons of Digital Radiography-CR vs.
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