50
Dose Information
2) Angular tube current modulation:
Based on the above described axial eff. mAs profiles,
the tube current is modulated during each tube rota-
tion. Therefore the angular attenuation profile is mea-
sured automatically during the scan and the tube cur-
rent is modulated accordingly in real time to achieve
an optimum distribution of the X-ray intensity for every
viewing angle.
Relation between relative attenuation and relative
tube current. The adaptation strength may be
adjusted by user separately for the left branch (slim)
and the right branch (obese) of the curve. This adjust-
ment effects all examinations. The gray lines here
indicates the theoretical limits of the adaptation (con-
stant dose resp. constant image noise). The absolute
(eff.) mAs value is scaled with the Image Reference
mAs value, which may be adjusted in the Scan Card by
the user.
rel. tube current
reference attention rel. attenuation
Image Quality
reference tube current
constant dose
obese
constant image noise
slim
strong increase
average increase
Weak increase
weak decrease
average decrease
strong decrease