Specialized Radiographic Technique Question And Answers

Specialized Radiographic Technique

Write short note on xeroradiography.
Answer. This is a relatively new method of recording image and in this technique the usual silver halide films are not used. No chemical developer, fier and no darkroom is required.

Xeroradiographic Unit has Following Parts

• Conditioning unit.
• Processor or developing unit.
• Cassette-protecting selenium plate.
• Xerox opaque paper.
• Charged toner particles.

Read And Learn More: Oral Radiology Question And Answers

There are two systems in Xeroradiography

• The Medical 125 system
• The Dental 110 system

The Medical 125 system

• This method in based on electrostatic process similar to that used for xeroxing.
• Image is fist recorded on a plate which is made up of aluminum and is coated with a layer of selenium.
• Before put to use, selenium particles are given a uniform electrostatic charge and are stored in a unit called as conditioner.
• After charging the plate is ready for use, it is placed in light tight and air-tight cassettes.
• When X-rays are put on the film or the film is exposed it causes selective discharge of the selenium particles depending upon the amount of radiation used and the relative density of the object.
• Pattern of electric discharge on the plate is referred as latent image.
• Latent image is then converted into visible image by a process called development in a unit called processor.
• In the processor, the plate is exposed to charged powder particles called as toner.
• Unique feature of xeroradiographic technique is to have both positive and negative replica.
• When positive current is applied to the processor negative toner particles are attracted and vice versa.
• When the development is complete, the visible image is transferred to paper in a machine referred to as a developer.

Dental Xeroradiograph system

• The dental xeroradiograph system has a different physical design.
• The image receptor plates are the size no. l and 2 films and fi into the patient’s mouth.
• The image receptors are charged and processed into a final permanent image in a single piece of equipment.
• To make an image, the photoreceptor is charged at the output station. It is then put intraorally, exposed, and returned to the input station.
• The plate passes over a toner station, where charged toner particles suspended in a liquid, vehicle are deposited on the plate to develop the image.
• Next the plate is dried to remove the liquid vehicle. The image is recovered from the plate by using a clear adhesive transfer station.
• The adhesive tape is brought into contact with the plate and pulls of all the toner particles.
• The image is protected by applying the adhesive with the image to a translucent backing strip.

Xeroradiography Advantages

• Reduction in exposure time.
• Wide latitude of exposure.
• Ease in manipulation.
• Exam of viewing.
• High contrast.
• Good detail, as this method gives excellent definition of thin, fie structures due to edge enhancement.
• Height of alveolar crest better seen.
• Caries seen more readily.
• Useful in endodontics.
• Detection of cancer.
• Imaging biomaterials.

Xeroradiography Disadvantages

• Electrically charged plate causes discomfort to some patients.
• Edge enhancement artifacts.
• Processors are expensive.
• Slower speed.
• Temporary image retention.

Indications in head and Neck Region

• Periodontal and periapical assessment to show good bony details.
• Cephalometric radiography to show the required hard and sof tissue landmarks on one fim.
• Sialography to show fie duct structure.
• Assessment of soft tissue shadows in pharynx and larynx.