Compare the radiation in pediatric patients thyroid submitted to chest X-ray using the position of the anode and cathode.

The study's primary goal was to compare radiation exposure in two different positions during chest x rays in children. It was conducted from June/2014 to July/2015, and included children from 0 to12 years old staying at the Pediatric Intensive Care Unit at the Instituto de Cardiologia de Porto Alegre, Brazil, with chest x ray requests during ICU stay. They were randomized to two groups: during the x ray, one group was positioned with the thyroid facing the anode end, and the other group was positioned with the thyroid facing the cathode end.

Inclusion Criteria:

• Younger than 12 years old
• Admitted to the Paediatric ICU at Instituto de Cardiologia de Porto Alegre
• Chest X ray requested by treating physician

Exclusion Criteria:

• Patients with scans that failed to comply with the technical criteria from the European Community Commission guidelines on quality criteria for diagnostic radiographic images in paediatrics, as evaluated by the radiologist doctors responsible for that exam report.