How is the CT Lung Scan Procedure Performed?

In a CT lung scan, several x-ray beams pass through the chest at various angles. Special sensors measure the amount of radiation absorbed by different tissues within the lung, including lesions and tumours.

In order to undergo a CT lung scan, your general physician must write you a letter of referral stating why he or she believes a CT lung scan is necessary in your situation. A CT lung scan will take place in either a hospital or in an outpatient radiology center.

At the start of a CT lung scan, the technologist ensures that the patient is correctly positioned on the table. The patient may have to be propped up with pillows to ensure that he or she maintains the correct position throughout the CT lung scan. The patient will lie still on this table. The table is rolled into the center of the CT scanner. For the first few scans, the table will move rapidly through the scanner to determine the best starting position for the CT lung scan. Once this has been determined, the table will move slowly through the cavity in the scanner for the remainder of the scans. As the table moves, the CT scanner revolves around the patient and emits and records x-ray beams. The different areas of the lung absorb different amounts of x-ray. The technologist will likely ask the patient to hold his or her breath for optimal CT lung scan results.

Though the technologist will not actually be in the room with the patient, an intercom within the scanner allows the patient and technologist to communicate throughout the procedure.

Once the scans have been completed, a special computer program then forms graphical cross-sections, or “tomograms,” based on the x-ray absorption differences.

The duration of the CT lung scan depends on the number of images needed to get the information the doctor requires. The exam typically takes anywhere from 15 to 30 minutes, but most of this is preparation time. The actual CT lung scan takes about 30 seconds.

At the conclusion of the CT lung scan, the technologist will look over the images to ensure sufficient images have been created to provide the radiologist with the necessary information. If more images are necessary, the technologist will ask the patient to stay for further scanning.