Keywords:
Dosimetric comparison, Radiation safety, Dosimetry, CT, Radioprotection / Radiation dose, Neuroradiology brain, CNS
Authors:
J. N. Balcombe1, J. Luckman2, M. Guindy1; 1Tel Aviv/IL, 2Ramat Hasharon/IL
DOI:
10.26044/ecr2019/C-0612
Results
|
Initial Period
Mean dose,
CTDIvol (mGy)
|
Following DRI correction
Mean dose,
CTDIvol (mGy)
|
Scanner one
|
30.9 (n=1093)
|
32.6 (n=1820)
|
Scanner two
|
36.4 (n=1784)
|
30.3 (n=2387)
|
CTDIvol of scanner one was 30.9 mGy,
in comparison to 36.4 mGy on scanner two,
an 18% difference.
Evaluation of all protocol parameters on each scanner revealed that the protocol parameters that are visible to the reading radiologist - slice thickness,
tube potential and iterative reconstruction mode - were identical across the two scanners.
There was a single difference,
in a parameter not visible to the reading radiologist- the noise index setting,
known on Philips scanners as DoseRight Index (DRI).
Correction of noise index level in the errant scanner to the correct value as determined by neuroradiology section chief resulted in dose reduction and near equalization.
Following correction,
CTDIvol of scanner one was 32.6 mGy,
scanner 2 was 30.3 mGY.
This represents a 17% dose reduction on scanner two after correction of the DoseRight Index.