Chapter 7: Quality Assurance; Dosimetry - GE HealthCare Revolution EVO EL Instruction Manual

Chapter 7: Quality Assurance

DOSIMETRY

Dosimetry information is provided in terms of the CTDI and CTDI
its associated DLP (dose length product) is automatically computed and displayed on the patient Rx
menu to assist in managing patient dose. This section provides a brief description to help you better
understand these dose reporting standards.
CTDI (Reference IEC 60601-2-44)
vol
The volume CTDIw (CTDIvol) describes the average dose over the total volume scanned for the
selected CT conditions of operation. The system computes CTDIvol automatically.
NOTE: System computations may vary slightly from manual calculations due to differences in round-
off or truncation operations.
e) Estimating CT scout scan
The ratio CTDIw / mAs is evaluated independently of the scout acquisition but with the same
settings of tube voltage and collimation as those of the scout acquisition.
Scout scans on
Revolution™ EVO
mode or mm/s table speed for fast mode.
175
CTDIvol SPR (scan projection RADIOGRAPHY) for scout dose defined above is displayed and
accumulated as part of CTDIvol based on the following justification. Although the dose distribution of
a SPR within the PHANTOM is different to the dose distribution of a tomographic scan, the average
dose expressed by the CTDIvol SPR in the PHANTOM can be considered as the same as for a
tomographic scan, if the CT CONDITIONS OF OPERATION are the same.
5805442-1EN Rev 2 (Nov. 2023)
© 2023 GE HealthCare
use 5 mm collimation with 100 mm/s table speed for normal
Quality Assurance
dose indices. Optionally CTDI
w
and
vol
7-1