[Intl_DxMedPhys] Displayed CTDIvol on Toshiba Aquilion 320 slice

[Dylan DeAngelis]

Good morning,

ACR-testing a Toshiba Aquilion 320 slice CT scanner, for a pediatric head "Volume" protocol with 0.5 x 320 configuration, we noticed that the displayed CTDIvol was changing based on the scan length (all other parameters kept the same). Going from 80 to 100 to 120 mm would change the CTDIvol by a few percent.

Is this typical? Does anyone have a solid explanation as to why it would happen? I understand that the "Volume" scan, being so wide, has some cone-beam properties, but I only think of this as having an affect on IQ. Does it also have an affect on the system's calculation of CTDIvol?

Apologies if this has been discussed before. I'm not very savvy with the ListServ search options.

Thank you,

Dylan DeAngelis, MS, DABR
NYS Licensed Medical Physicist
(Diagnostic Radiological Physics and Medical Nuclear Physics)

Upstate Medical Physics - Diagnostic Radiology, Medical Nuclear & Medical Health Physics, P.C.
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