Today I was approached to set up a protocol for scanning Brains with the intention of performing surgical planning. We have been doing these for years, and never had issues with our helical method. However, some of the assistants in charge of facilitating surgeons with these images and surgical models have recently made a software change, and are requesting the following parameters:
Scan Range - Hard palate to Skull vertex
Slice Thickness 1mm
Must be Axial(Conventional Scanning mode)
Standard soft tissue algorithm
Scanner: CT Aquilion 64slice
My question here is: What scan mode (scan distance in z axis) should be used for this exam? Our current axial brains are set-up at 2.0 x 4 thickness, giving it 8mm of coverage per axial acquisition(which is fine due to our reconstructions being 4mm slices.) Bringing this down to 1.0 x 4 to meet the 1mm requirement generates a large number of single axial acquisitions that allow for patient motion and tube heating. The scanner does offer the option of using 0.5 x 64 in the axial mode, but our Toshiba engineer advised against it. Would you be able to explain why this mode should be avoided? (beam widening effects perhaps?) Any ideas on the protocol parameters? I appreciate any input you have on this situation. I will provide you with any additional information you require if necessary. Thank you
here is the answer courtesy of Alessandra Barelli
Clinical Marketing Manager at Toshiba,
Thanks for your question regarding image protocols for CT brain surgical planning.
0.5 mm x 64 row acquisition is an optional scan mode on Aquilion 64 CX systems. If your system does allow this scan mode the following parameters can be selected:
Acquisition mode: Scan and Scan 0.5 mm x 64 selectable within the Scan Details Tab
Slice thickness: specify 1 mm x 1 mm at Recon Details Tab, also under this Tab go to DETAIL and make sure you have coneXact algorithm under interp. option.
Reconstruction FC: 23 or other Head FC of your physician's choice.
X-ray parameters should be determined by your physician per their image quality needs
If additional assistance is needed please log on to toshibalearningcenter.com for complete protocol guides or contact us at medical.toshiba.com