All humans are exposed to natural radiation {cosmic rays, subsoil,terrestrial (rocks and soil)} with no significant health hazards though.

A slight health impact is due to exposure to technical sources (tv’s, fluorescent screens, smoke detectors, air travels) while nuclear industry causes greater damage.

At the category of insignificant risk exams (probability of lifetime radiation-induced cancer 1: 1.000.000) belong chest, teeth and limbs x-rays which are equivalent to radiation intake equal to a few-day background radiation or to a return-flight to usa.

The very low risk category (1:100.000 or 10.000) includes abdominal x-rays, mammographies and brain ct scans which equal to a few month natural radiation or to a risk of a 10.000 km car journey or a 4 years industry work.

The low risk group (1:10.000 or 1.000) includes higher dose examinations which equal to a few year of environment radiation such as chest (3,6 years) or abdominal -pelvic (4,5 y) ct scans.

Since the last category of exams -especially when repeteed- implies a theoretical danger of health injury it is essential to be performed after strict medical referall when the diagnostic benefit outcomes the hidden risks and assures that low dose tecniques are adopted.

Health hazard from medical radiation is lower for older people – who are exposed to more examinations- while it is three time more for children. however, the potential health risk of a chest x-ray is much more lower than the possible risk of swimming in nursery age.

Summarising most radiology exams excluding u/s and mri, use ionizing radiation and therefore they have a cumulative biological cost. There are no x-rays, dental panoramics or mammographies with zero radiology exposure- not even the digital ones.

Taken into consideration that exams with no reason are never (must never be) performed, the fear of radiation should never deters us from the subscribed treatment, otherwise, consequences may be much more hazardous to our health.

Under appropriate conditions all medical radiology practices are safe. The procedure includes:

a) justification by the referring physician, the most responsible for recommending the appropriate exam, since he should have taken into account previous ct scans or x-rays exposures (it has been proved crucial for patients to keep a radiology archive).
b) optimization of radial exposure in the lab: modern medical equipment offers radio operator experts the choice of selecting the minimum biological dose necessary which in combination with radiation protection facilities (beam focus, radiation field restrictions, use of lead aprons) optimises the results.