INTRODUCTION
Preparation of radiographic equipment is a favourite in the practical examination. The format of the task is usually to position a patient for radiographic examination of a named part of the anatomy (see Practical Tasks: Positioning). The equipment should be gathered together and correctly set up prior to positioning. Since x-rays are hazardous, safety is of paramount importance both in the exam and in practice. It is therefore vital to familiarise yourself with all the equipment that may be necessary and be able to identify any faults to avoid taking radiographs of poor diagnostic quality. Efficient organisation and preparation will reduce the time taken in radiography, and will subsequently lower the duration of sedation or anaesthesia of the patient.

1. THE PROCESSOR
   • Is the processor at the correct temperature; ie. 20°C for manual processing or 28°C for automatic processing?
   • Is the darkroom clean, dry and well organised with sufficient supplies of radiographic film of the correct film-screen combination?

   If the answer to these questions is yes, it is safe to go ahead with the necessary radiographic procedures. If the answer is no; the processed films may be poorly developed and non-diagnostic. It cannot be stressed enough that repeated, unnecessary exposures are hazardous to both the patient and the radiographer; and therefore all steps must be taken to ensure that avoidable problems are not encountered.

2. THE CONTROLLED AREA
   Are the following displayed?
   • Red warning light at access points.
   • Radiation warning symbol at access points.
   • Local rules

   All personnel involved in radiography should have read and understood The Ionising Radiations Regulations 1999, The Approved Code of Practice for the Protection of Persons Against Ionising Radiation Arising from any Work Activity and The Guidance Notes for the Protection of Persons Against Ionising Radiations Arising from Veterinary Use 1988.
   
   

3. THE X-RAY MACHINE
   Always check the following:
   
   • Collimation device/light beam diaphragm alignment.
   • Aluminium filter.
   • Line voltage.
   • Service records.
4. PERSONAL SAFETY
   The following should be available and always be used:
   
   • Lead aprons.
   • Lead gloves.
   • Lead sleeves.
   • Personal dosemeter.
   • Lead-lined table or lead sheeting to be place beneath x-ray cassette.
   • Lead-lined wall (if this is not feasible, a lead screen may be used).
   • Aluminium filter incorporated into the x-ray machine (this is required by law).
   • Collimation device (light beam diaphragm is far preferable to a cone).
   • Exposure button allowing the operator to stand at least 2m away from the primary beam (ideally the operator should be able to stand outside the room in which x-rays are taken).
   • Grids for exposures of body tissues 10cm thick or deeper.
   • Compression bands to apply to large areas of body tissue.
5. CASSETTE
   This should contain a film of the correct film-screen combination, be of a suitable size for the radiographic views required, possess clean intensifying screens and be impermeable to visible light. Some cassettes are designed to hold a stationary grid (which should be positioned between the cassette and the patient).
   If non-screen films are used, these should be clean and dry and contained within a light proof envelope. Non-screen film must be placed a certain side up within its envelope.
   
   
6. POSITIONING AIDS
   The following may be useful (refer to Practical Task: Positioning for further details):
   • Radiolucent troughs.
   • Sandbags.
   • Ties.
   • Foam wedges.
   • Wooden blocks
7. OTHER EQUIPMENT
   • Marking devices; lead letters or lead tape are best.
   • Lead sheeting to protect parts of the patient not radiographed (also the film if only part used in one exposure).
8. THE PATIENT
   Having established all the previously mentioned criteria; only then is it prudent to sedate or anaesthetise the patient for radiography. The following points are critical:
   • Sedation or anaesthesia are essential unless contra-indicated; manual holding is to be avoided if at all possible.
   • Ensure that endotracheal tubes, an anaesthetic machine and all the necessary anaesthetic equipment are on hand in the controlled area.
   • Emergency resuscitation equipment should also be available.
   • An assistant should be present to monitor the sedated or anaesthetised patient during the radiographic procedure

CHECK-LIST FOR THE PRACTICAL EXAMINATION

Start from the bottom upwards….

1. Lead sheeting; put in place even if the table is lead lined - double thickness is better.
2. Cassette.
3. Marker - Left or right marker plus date and patient identification; this should be in lead or perspex letters or inscribed on lead impregnated tape.
4. Grid; ensure that this is the correct way up (a grid ratio of 8:1 is suitable). The Potter Bucky moving grid incorporated into the table top is by far the best, but failing this a focused or pseudo-focused grid is acceptable (parallel grids may cause "grid cut-off"). The grid should be situated between the cassette and the patient.
5. Positioning aids - choose those relevant to the view required.
6. Finally, having established all other factors, position the patient (refer to Practical Task: Positioning).
7. Ensure that you are able to state the point of collimation of the primary beam.
8. Be aware of any potential hazards associated with radiography and be able to state these to the examiner (read this chapter fully and refer to regulations stated in Q1).