Radiation Protection In Veterinary Medicine - Recommended Safety Procedures For Installation And Use Of Veterinary X-ray Equipment - Safety Code 28

7. Procedures to Reduce Dose to X-Ray Personnel

The guidelines and procedures outlined in this section are primarily directed toward occupational health protection. Adherence to these guidelines will also provide protection to visitors and other individuals in the vicinity of an X-ray facility. However, the safe work practices and procedures for using various types of X-ray equipment should be regarded as a minimum to be augmented with additional requirements, when warranted, to cover special circumstances in particular facilities.

To achieve optimum safety, operators must make every reasonable effort to keep exposures to themselves and to other personnel as low as reasonably achievable, with the limits specified in Appendix I being regarded as maximum values not to be exceeded.

7.1 General Recommendations

1. An X-ray room must be used for only one X-ray procedure at a time.
2. All entrance doors to an X-ray room should be kept closed while a radiographic procedure is being performed.
3. X-ray machines that are energized and ready to produce radiation must be supervised.
4. The X-ray room must contain only those persons whose presence is essential when a radiological procedure is carried out.
5. All personnel must fully use all protective devices available.
6. The X-ray tube housing must never be held by hand or supported by any part of the body during operation.
7. Where a control booth or protective barrier is available, operators must remain inside or behind when making an irradiation. If a control booth or protective screen is not available, protective clothing must be worn.
8. Personnel must keep as far away from the X-ray beam as is practicable at all times. Exposure of personnel to the X-ray beam must never be allowed unless the beam is adequately attenuated by the animal and by protective clothing or barriers.
9. If necessary, the animal should be sedated or holding devices used during radiography. However, if this is not possible and a person must restrain the animal, protective aprons and gloves must be worn, and irradiation by the X-ray beam must be avoided. Individuals should avoid performing these duties regularly.
10. A radiographic cassette holder must always be used. The radiographic cassette must never be held by hand.
11. All operators of X-ray equipment, together with personnel who routinely participate in radiological procedures and others likely to receive a radiation dose in excess of 1/20 of the permissible dose equivalent limits specified in Appendix I, must wear personal dosimeters.
12. When a protective apron is worn the personal dosimeter must be worn underneath. Where irradiation to the body may be substantial, a second personal dosimeter located at the neck level may be worn. In such cases consultation with the proper federal or provincial agency may be helpful. If extremities are likely to be exposed to higher doses, additional monitors should be worn on the extremities.
13. Where radiation doses in excess of 20% of the maximum specified in Appendix I are being received regularly by any one person, the nature and cause of the irradiation must be investigated and appropriate remedial steps must be taken to improve techniques and protective measures.
14. X-ray equipment must be operated only by or under the direct supervision of qualified individuals.
15. For table-top radiography when the sides of the table are not shielded, a sheet of lead at least 1 mm in thickness and slightly larger than the maximum beam size should be placed immediately beneath the cassette or film.
16. The fastest combination of films and intensifying screens consistent with diagnostically acceptable results and within the capability of the equipment should be used.