Introduction
- Radiography of the skull requires general anesthesia. This is the only way to obtain accurate projections.
- A grid is necessary when patient thickness >10 cm.
- The different skull shapes are treated similarly for the basic projections.
- Specialised projections such as tympanic bullae require adaptation of technique based on the shape of the skull.
- Radiography of the skull for fractures may be of questionable value as the presence of a fracture is considerably less significant than the presence of neurological signs. It may, however, in some cases, be of value in explaining the reason for the signs when trauma is a possibility but has not been observed.
- When using non-screen film for intraoral radiography the increase in exposure required is immense. It is therefore necessary to ensure that the equipment is adequate, that the finger is not removed from the exposure button before completion of the exposure, and, most importantly, that staff do not re-enter the room before termination of the long exposure.
- The objective is to produce well-positioned radiographs which are correctly exposed and developed, free from movement blur and free from artefact.
- The anatomical marker, the patient's identification, the date, and the name of the hospital or practice should be clearly shown.
Uses
- → Fracture
. - → Bony neoplasia .
- → Soft tissue neoplasia
, eg nasal tumors . - → Temporomandibular joint disease .
- → Hydrocephalus .
- → Nasal foreign body .
- → Ear disease and tympanic bulla involvement .
- → Infectious rhinitis .
Requirements
Materials required
Minimum equipment
- X-ray machine.
- Cassettes with high detail screens.
- Processing facilities.
- Immobilization and positioning aids: sandbags, foam wedges, blocks.
- Protective clothing, eg lead-rubber aprons, although patient must be under general anesthesia for complete study.
- For the intraoral nasal view, non screen (direct exposure) film is required. Radiation therapy localization film is optimal for this use (individually wrapped).
Dental occlusal film is suitable for small breed dogs. - Flexible screens and casetttes are also available which are useful for this technique as they can be positioned within the oral cavity of an anesthetized patient.
If not available, a suitable film can be cut to size and inserted into light-tight envelopes. - Film labelling system.
Ideal equipment
- High output X-ray machine.
- Rare earth high detail screens.
- Automatic processing facilities.
Minimum consumables
- X-ray film.
- Pharmaceuticals for anesthesia.
Sequelae
Reasons for treatment failure
Poor positioning
- Because of the fine structures involved, positioning must be accurate.
- The most common problem is rotation.
- To avoid this the skull must be considered in all its planes. Draw imaginary lines and use fingers and hands to judge when a plane is in its correct position.
- Inadequate number of views.
- Wrong exposure factors.
- Poor processing.
- Equipment failure.
- Failure to label film.
