The following are examples of best practices in reducing staff radiation exposure. The list is not comprehensive, and the trained operator must always evaluate the specific demands and risks of each exposure. The CVM Radiology staff have extensive experience, and will always be the best resource for questions.
Best Practices, general:
- Always wear all available dosimeters (body badge and finger rings) to monitor the effectiveness of your radiation safety procedures.
- Wear all appropriate PPE, such as lead apron and gloves. Except for patient, Oregon law requires that no unprotected body parts shall be in the useful beam.
- Whenever possible, use sedation, sandbags and other restraints instead of holding patients.
- Scatter radiation from the patient is a significant source of personnel radiation exposure.
- Always position yourself well away from the potential scatter radiation fields. Remember the Inverse Square Law.
- Always make use of available moveable barriers to increase shielding between you and scatter radiation.
- Close collimation reduces scatter and significantly reduces personnel dose, and dose to the patient.
- Higher kVp with appropriate reduction in mAs reduces radiation dose; however kVp must be appropriate for the study.
- e.g. 70kVp@15mAs results in less dose than 60kVp@30mAs
- No unauthorized visitors or personnel are allowed in the x-ray room during exams.
Patient Holding
- When an animal must be held in position during radiography, mechanical supporting or restraining devices shall be available and used as appropriate. The radiology staff have extensive experience in these techniques and should be consulted on best practices.
- If the animal must be held by an individual, that individual shall be protected with appropriate shielding devices, such as protective gloves, thyroid shield and apron, and that individual shall be so positioned that no part of the body will be struck by the useful beam. The exposure of any individual used for this purpose shall be monitored with appropriate personnel monitoring devices.
- In all cases, steps should be used to prevent an individual from having to hold the cassette/CR panel/DR panel by using all available radiation safety equipment. In the rare instance in which it must be held, it must be held by individuals not occupationally exposed to radiation;
- No individual must be regularly employed to hold or support animals during exposures. Radiology staff must not perform this service except very infrequently and then only in cases that no other method is available.
- It is against the principles of keeping radiation exposure as low as reasonable achievable (ALARA) to designate an employee to regularly stand near a radiation field as part of their work duties. This should instead be performed by personnel that are generally not present in the radiology rooms, thus keeping radiation exposures to each individual ALARA. Consult the CVM radiologists for best practices for your situation.
Fluoroscopy
- Do not remove lead drapes from the table, these provide significant shielding from scatter radiation.
- Use of intermittent fluoro reduces patient and operator exposure.
- Ensure fluoro is energized only when operator is actively looking at the fluoro image.
- Scatter radiation fields vary significantly with position of tube head. Be aware of position of moveable shielding and lead PPE (aprons, gloves...) with respect to potential scatter fields.
- An attendant with their back to the fluoro table during operation may require a wrap-around style apron, or other additional shielding.
- X-ray tube should be positioned below the table when possible. When positioned above the table, extra care should be taken to position barriers to protect from the increase in scatter radiation.
- Always wear all available dosimeters (body badge and finger rings) to monitor the effectiveness of your fluoro radiation safety procedures.
Portable X-Ray Unit
- Do not hold the x-ray machine during exposures
- Standing near the x-ray machine may greatly increase exposure to scatter radiation from the patient.
- Using an exposure control cord and stepping as far as feasible away from the x-ray machine and patient during exposure will significantly reduce your exposure to scatter and leakage radiation.
- Use long handled cassette holders or other device to position personnel away from the primary and scatter radiation fields.
- No worker shall ever be in the primary beam.
Image
