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2.3.3 Minimize multi-phase contrast CT examinations
Scan only one series if possible.
•
CT studies with and without contrast material are not always needed.
•
Multiphase imaging may double or triple the dose and may not add diagnostic information to
the study.
•
If multi-phase studies are needed, use a lower dose technique for the non-contrast series
compared to the contrast series and limit the scan only to the organ or anatomical region
indicated.
2.3.4 Properly center all patients in the gantry
Center all patients in the gantry to allow the bow tie filters to deliver dose where it is needed and
filter more where it is not.
•
This is especially important using automatic exposure control techniques such as SmartmA,
and Organ Dose Modulation to further reduce unnecessary radiation exposure.
•
Patients not properly centered may be under or over exposed to radiation if the table height
is set too high or too low.
2.3.5 Lower mA settings for chest and bone imaging
Consider using a lower mA setting and higher Noise Indexes if SmartmA is used for chest and
bone imaging. Higher resolution/dose imaging is typically unnecessary for these types of studies
where there is high inherent contrast between the structures being imaged.
2.3.6 Scan signal-to-noise
Limit the highest quality images requiring the highest radiation dose to very specific indications
such as angiography or visualizing small subtle lesions. Studies with higher noise may be just
as diagnostic and require lower dose.
2.3.7 Consider using in-plane Bismuth shields
Use in-plane Bismuth shields to reduce the patient dose.
•
Recent studies have shown dose reductions to sensitive organs, such as breast tissue in
females, the thyroid, and eyes without significantly affecting image quality.
•
If used with SmartmA, they should be put in place after the scout scans are acquired to
reduce technique overcompensation.
2.3.8 Use pediatric positioning accessories
Use papoose boards and neonatal immobilizers, as needed, with certain patients.
•
These accessories are sometimes helpful to secure the patient and keep the patient still.
•
Results in less patient motion and therefore, less repeated exams.
2.3.9 Make a kid friendly environment
Help pediatric patients feel less scared.
•
Put pictures of animals on the wall or ceiling.
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Revolution CT User Manual
Direction 5480385-1EN, Revision 1
2 Radiation Exposure
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Troubleshooting
