Respiratory-gated imaging techniques are medical procedures used in radiology to reduce motion artifacts caused by respiratory movements during the acquisition of images, particularly in imaging exams such as computed tomography (CT) and magnetic resonance imaging (MRI). These techniques synchronize the image data acquisition with the patient's breathing pattern, allowing for more accurate and clearer images.

During a respiratory-gated imaging exam, the patient is instructed to breathe normally while data is collected. The system then monitors the patient's breathing motion, often through the use of external sensors or internal markers, and triggers image acquisition only during specific phases of the breathing cycle, typically during the end-expiratory phase when respiratory motion is minimal. This results in a series of images that are less affected by respiratory motion, improving diagnostic accuracy and reducing the need for repeat exams.

Respiratory-gated imaging techniques are particularly useful in imaging exams of the chest and upper abdomen, where respiratory motion can significantly degrade image quality and compromise diagnostic confidence. Examples include the evaluation of lung nodules, tumors, or other pulmonary pathologies, as well as the staging and treatment planning for various cancers in the thoracic and upper abdominal regions.

In medical terms, "andning" refererar till den process som innebär att luft fyller lungorna när vi andas in (inhalering), och att luften lämnar lungorna när vi andas ut (exhalering). Under inandningen dras syre rik av syre in i kroppen, medan koldioxid, ett avfallsgas som produceras under cellandningen, avges under utandningen.

Andningen är en nödvändig livsfunktion som kontrolleras av det autonoma nervsystemet och regleras för att upprätthålla en balans mellan syre och koldioxid i blodet. Andningsfrekvensen varierar beroende på aktivitetsnivå, ålder och hälsotillstånd.