Protective measures against radiation - Radiography
Protective measures against radiation
In dental practice, measures must be taken to minimize the radiation load. This is the ALARA principle. ALARA is the abbreviation for the English "as low as reasonably acheavable". The placement of the X-ray apparatus must already be taken into account when constructing the practice room and adjustments may be required in an existing situation. The dentist is obliged to protect his employees, himself and the neighbors, as much as is reasonably possible.
Measures for dentist and employees
- Take a distance from the x-ray source; the intensity decreases quadratically with increasing distance.
- Provide protection through a ray-absorbing partition. This is usually a brick or concrete wall or a wooden partition with a lead layer in it.
- If there is no dividing wall, the dental staff and caregivers must leave the room.
- Mount the timer and the print mechanism at a distance from the device, behind the partition or in another room, forcing the operator to distance himself from the radiation source.
- Use sensitive or digital films: the exposure time can be shortened as a result.
- Use an X-ray device with a high kilovoltage: this causes hard X-rays. The X-ray device must be equipped with a sufficiently thick filter.
- Ensure a good position relative to the primary beam. It has been found that the intensity is lowest obliquely behind the tube at an angle of 90-135 ° with the central radius. Right behind the device the intensity is higher due to the scattered radiation.
Radiation protection measures with regard to the patient
- Use a device with a good filter, a high tube voltage and a narrow, focused beam.
- Avoid taking unnecessary photos.
- Use a lead collar for children (see image below).
- Position the patient in such a way that no radiation from the primary beam through or along the film disappears into the body behind the lead protection.
- Rather not take X-rays with a gravida (pregnant woman), especially not in the first three months.
- Use a rectangular cone instead of a round or pointed cone. This cone reduces the field size of the effective rays and leads to a 50% reduction in radiation load for a patient (see image below).