RT Journal Article SR Electronic T1 Comparison of low-dose vs. high-dose CT attenuation correction for brain PET JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1490 OP 1490 VO 50 IS supplement 2 A1 Bing Bai A1 James Hamill A1 Peter Esser A1 Mark Slifstein A1 J Mann A1 Ramin Parsey YR 2009 UL http://jnm.snmjournals.org/content/50/supplement_2/1490.abstract AB 1490 Objectives To compare the quantitative accuracy of PET brain scans with low dose and clinical dose CT based attenuation corrections, phantom studies were acquired with a 64-slice PET/CT. Methods A striatal phantom with five compartments (left/right putamen, left/right nucleus caudate, rest of the brain) filled with F-18 solutions was scanned using a Biograph scanner. The phantom included both soft-tissue and bone substitute. Four scans were acquired with different striatum to background ratios (putamen:brain=25,12.5,3.75,0.625; caudate:brain=20,10,3,0.5). A high dose (HD)-clinical CT (120 kVp, 340 mAs effective, pitch=0.55, 1 sec/rotation, CTDIvol=57.8mGy) and a low dose (LD) CT (120 kVp, 7 mAs effective, pitch=1.5, 0.5 sec/rotation, CTDIvol=1.22mGy) were acquired for each PET scan. PET data were reconstructed using Fourier rebinning followed by 2D filtered backprojection. Four 3D volumes of interest (VOIs) were drawn in the striatal compartments manually. One 2D region of interest (ROI) was drawn in the background. PET images reconstructed with HD and LD CT attenuation correction were compared. Results The difference of VOI:background ratios between PET images reconstructed using HD and LD CT were small for all VOIs (0.08 ± 0.81%, range -1.5 to 1.1%). An axial profile of mean 2D ROI value showed increased difference (up to 2%) toward the bottom of the phantom, where more bone structures were present. Conclusions Initial data suggest that low dose CT is comparable to, thus can possibly replace, high dose CT using clinical parameters for attenuation correction in brain PET research studies and some clinical scans.