Operating instructions

54
Dose Information
After the Topogram has been scanned the (eff.) mAs
value in the Routine Card and Scan Card displays the
mean (eff.) mAs which was estimated by CARE Dose
4D based on the Topogram*. After the scan has been
performed this value is updated to the mean (eff.) mAs
which were applied. The values may differ because of
the on-line modulation according to the patient’s
angular attenuation profile.
Adjusting the Image Noise
The correlation between attenuation and tube current
is defined by the analytical function described above.
This function may be adjusted to adapt the image qual-
ity (image noise) according to the diagnostic require-
ments and the individual preference of the radiologist.
– To adapt the image noise for a scan protocol the
Image Quality Reference mAs value in the Scan Card
may be adjusted. This value reflects the mean (eff.)
mAs value that the system will use for a reference
patient with that protocol. Thereby the reference
patient is defined as a typical adult, 70 kg to 80 kg or
155 to 180 lbs. (for adult protocols) or as a typical
child, 5 years, appr. 20 kg or 45 lbs. (for child proto
-
cols). Based on that value the CARE Dose 4D adapts
the tube current (resp. the mean (eff.) mAs value) to
the individual patient size.
*For the tuning of the CARE Dose 4D parameter set-
ting to individual preference of image quality it is rec-
ommended to keep track of this value and to com-
pare it with the values used without CARE Dose 4D.