GE Revolution CT - Page 240

Illustration 3:
Number Description
1 Tube current reduction area
2 Head first
3 Feet first
The mA reduction rate on front side of the patient and the mA reduction tube angle are below.
Table 4: mA Reduction Rate for ODM
SFOV
mA Reduction Rate
(front side)
mA Reduction Range FWHM
(tube angle)
Head, Small Head, Ped Head Up to 30% 100
Large Body, Medium Body, Small Body,
Ped Body
Up to 40% 150
NOTE: When patient is in prone position, the mA is reduced from the table side, as it is the
direction of the front side of the patient.
ODM effectiveness will be affected by patient centering. ODM is applied relative to the anterior
surface of the patient and is relative to the isocenter of the SFOV. Thus incorrect positioning of
the patient in the AP direction will change effectiveness in the reduction of dose to
radiosensitive organs.
Organ Dose Modulation builds on the SmartmA feature to enable even further patient dose
reduction. By modulating the X-ray tube current as a function of X-ray tube angle, ODM enables
targeted reduction of the X-ray tube current towards the anterior surface of the patient, providing
enhanced dose reduction to radio-sensitive organs of the patient while maintaining overall
image noise.
In a similar way to other AEC features, the effectiveness of ODM is impacted by patient
centering. To realize the expected dose reduction, the patient should be positioned in the center
of the SFOV.
Revolution CT User Manual
Direction 5480385-1EN, Revision 1
240 2 Scan Theory