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How is the CT Chest Scan Procedure Performed?
In a CT chest 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 chest, including lesions and tumours.
In order to undergo a CT chest scan, the patient’s general physician must write
a letter of referral stating why he or she believes a CT chest scan is necessary
for the patient. A CT chest scan will take place in either a hospital or in
an outpatient radiology center.
At the start of a CT chest 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 chest 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 chest 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 chest absorb different amounts of x-ray. The technologist
will likely ask the patient to hold his or her breath for optimal CT chest 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 chest 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 chest
scan takes about 30 seconds.
At the conclusion of the CT chest 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.
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