Question: How far away do nurses need to stand to avoid irradiation during a typical mobile chest x-ray?
The fact is, occupational exposure from diagnostic x-rays whilst working in the the hospital is small and should not be much grater than normal background radiation.
However, during a normal shift in areas such as intensive care, theatres and the emergency department, there can be many mobile x-rays taken. It is easy to be concerned that you might unwittingly receive radiation exposures as you go about your work in these environments.
The 3 things you need to think about to minimise your X-ray exposure are:
- Time of exposure.
- Distance from the primary beam.
- Shielding (lead gowns, or objects such as walls etc).
X-ray exposure consists of a primary beam aimed at the patient, as well as scattered radiation reflected in all directions from the target area.
The important thing to remember is that the intensity of radiation decreases rapidly as the distance from its source increases. In fact, If you double the distance, you reduce your exposure by a factor of four.
Stay clear of the primary beam pathway.
There should be little, if any radiation at a radius of 3 metres from the direct beam and target. 3 giant steps.
If you are pregnant, the above steps should keep you safe, however it is probably prudent to avoid exposure altogether when possible.
What if I need to be closer than 3 metres?
If nursing care necessitates working within 2 metres of a patient being x-rayed, lead protective gowns should be worn.
For this reason x-ray protective apparel should be easily available to staff working in areas where this may occur.
Protective covering should ideally consist of lead lined gowns and thyroid shielding.
Stay clear of the primary beam. Simply done by stepping away from the imaginary straight line running from the x-ray camera, through the patient and off into infinity.
But the exposures we are talking about here are typically very small. One study (Cupitt 2001) of nurses in an 8 bed ICU, who continuously wore film badge dosimeters whilst on duty, found a negligible cumulative exposure over an 8 week period. In fact 3 of the badges returned an undetectable reading.
And what if I am pregnant?
A second study of a pregnant nurse working in a cardiac catheter lab who wore a real-time personal monitor as well as a foetal dose monitor, again the cumulative and point of care readings were little more than background radiation levels.
There is some scientific disagreement as to whether diagnostic x-ray doses can harm the unborn child. There may be increased risk of miscarriage, foetal damage, or cancer, and it is recommended that during the entirety of pregnancy, the unborn child should not be exposed to more than 0.5 Rad.
To give some perspective…the amount of exposure to the foetus of a patient having 2 chest x-rays is: 0.00007 Rad.
Even so, it is probably prudent not to expose it to unnecessary radiation during this time of rapid cellular development. The most sensitive time for foetal central nervous system teratogenesis is between 10 to 17weeks gestation.
By taking the simple precautions of staying outside the 3 metre circle ( 3 giant steps) and avoiding the primary beam you will be OK.
- Radiation and the Pregnant Nurse | Cath Lab Digest [Internet]. Available from: http://www.cathlabdigest.com/articles/Radiation-and-Pregnant-Nurse
- Radiation exposure of nurses on an intensive care unit – Cupitt – 2001 – Anaesthesia – Wiley Online Library [Internet]. Available from: http://onlinelibrary.wiley.com/doi/10.1046/j.1365–2044.2001.01870.x/full
- Radiation Safety on ADVANCE for Nurses [Internet]. [cited 2015 Feb 18]. Available from: http://nursing.advanceweb.com/Continuing-Education/CE-Articles/Radiation-Safety.aspx