SHELDON LIU, 1223168
Improper contact of the film screen may cause blur and magnification. Screens are composed of a base and emulsion layer that is made of Gelatin and silver halide crystals (Bushong, 2013). X-rays interact with silver halide to create light evenly dispersed throughout the surface of the film. If contact is not uniform, the distance light required to travel will differ from one area to another. The result would produce distortion, magnification, blur, or artifacts. A radiographic film is very sensitive and can be highly susceptible to damage. A few examples of mishandling that can cause improper film screen contact include: dirt and debris, scratches and scuff marks from dropping the cassette.
There are two different cassettes in B114 that vary in its speed; 100 and 400 speed. 400 speed is known for its higher resolution compared to the lower 100 speed. Placing the wrong film into the wrong cassette could affect the quality of the image. As seen on Figure 1. The use of a higher speed cassette resulted in an overexposed image of the test tool.
Figure 1.
There are two different cassettes in B114 that vary in its speed; 100 and 400 speed. 400 speed is known for its higher resolution compared to the lower 100 speed. Placing the wrong film into the wrong cassette could affect the quality of the image. As seen on Figure 1. The use of a higher speed cassette resulted in an overexposed image of the test tool.
Figure 1.
Radiographic film should be stored at temperatures lower than approximately 20 degrees Celsius and <60% humidity (Bushong, 2013). Heat and humidity could affect the film, especially over a period of time by distorting its shape. Therefore, the film will not make proper contact with the screen, as well as reducing contrast because of increased fog. It is important to check the temperature of the storage space where the film screens are kept to avoid issues in regards to film/screen contact.
The cassette has a light tight seal to maintain its integrity. During the process of closing the cassette, the screen makes even contact with the film and forces any air out of the space. Layers of compressible foam are built in to produce force to hold the screens tightly against the film. Proper care and technique of replacing the films in darkrooms will prevent screen/film contact problems from occurring.
Poor film/screen contact would manifest on a chest x-ray by the low quality it produces. There will be a distortion in magnification of anatomy that can present itself as pathology or hide important information. For instance, a distorted magnified heart on a chest x-ray could be misdiagnosed as a patient having cardiomegaly. Artifacts from dirt and debris can cover lung calcifications.
The cassette has a light tight seal to maintain its integrity. During the process of closing the cassette, the screen makes even contact with the film and forces any air out of the space. Layers of compressible foam are built in to produce force to hold the screens tightly against the film. Proper care and technique of replacing the films in darkrooms will prevent screen/film contact problems from occurring.
Poor film/screen contact would manifest on a chest x-ray by the low quality it produces. There will be a distortion in magnification of anatomy that can present itself as pathology or hide important information. For instance, a distorted magnified heart on a chest x-ray could be misdiagnosed as a patient having cardiomegaly. Artifacts from dirt and debris can cover lung calcifications.
References
Bushong, C. S. (2013). Radiologic science for technologists: Physics, biology, and protection
(10th ed.). St. Louis, MO: Elsevier Mosby.
(10th ed.). St. Louis, MO: Elsevier Mosby.