Increase Slice Thickness; Radiation Exposure And Dose Reporting - GE Revolution CT User Manual

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Break the imaging range into multiple groups to match patient's breath-hold capability.

2.2.6 Increase slice thickness

Generally speaking, thicker slice images can provide lower noise than thinner slice images for
the same dose. Consider using 1.25 or 2.5 mm slice thickness with 50% overlap as opposed to
0.625 mm slices for areas with large anatomical structures when reformats may be needed.

2.3 Radiation exposure and dose reporting

It is well known that normal weight adult techniques should not always be applied to large
patients since this will likely decrease the image signal-noise ratio for the acquisition due to
inadequate exposure. Generally speaking, higher radiation exposure is usually used for very
large patients to improve image quality to compensate for dose attenuation.
It is critical to remember that the body filter only uses the 32 cm CTDI phantom for dose
reporting purposes (CTDIvol displayed in the
screen and the Dose Report). In other words, when looking at the actual absorbed dose for the
large patient, understand that the dose may be lower than reported if the part scanned is larger
than the phantom tested. Keep this in mind when adjusting scan parameters to fit patients who
are larger than the phantoms tested.
NOTE: You have to balance between image quality level for diagnosis and responsibility for
the delivery of higher radiation doses for larger patients, especially in abdomen and
pelvis exams.
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Direction 5480385-1EN, Revision 1
Dose Information area on the Scan Settings
Revolution CT User Manual
2 Large Patients