TY - JOUR T1 - Impact of non-rigid and local rigid image registration on PET/CT response assessments JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 2073 LP - 2073 VL - 52 IS - supplement 1 AU - Floris van Velden AU - Paul van Beers AU - Linda Velasquez AU - Wendy Hayes AU - Adriaan Lammertsma AU - Ronald Boellaard Y1 - 2011/05/01 UR - http://jnm.snmjournals.org/content/52/supplement_1/2073.abstract N2 - 2073 Objectives The aim of this study was to investigate the impact of various image registration strategies on FDG PET/CT response assessment in case volumes of interest (VOIs) are defined on the baseline scan only. Methods Double baseline (n=11) and both early and late response whole-body FDG PET/CT scans were acquired in subjects with advanced gastrointestinal malignancies. Test and retest studies were performed within 10 d. In total, more than 19 liver and lung lesions could be identified. Non-rigid and local rigid image registration techniques were applied to PET or CT. VOIs drawn on test scans were projected onto retest and response scans to derive: (1) Dice similarity coefficients (DSC), and (2) test-retest (TRT, %difference) and response based on SUVmax, SUVmean, volume and total lesion glycolysis (TLG). VOIs drawn independently on all scans were used to obtain reference TRT and response data. Results CT-based registration provided poor results and therefore only PET derived registration results are shown. SUVmax TRT and responses were similar for all registration methods. TRT of other parameters was better for non-rigid than for rigid image registration. Observed responses differed between the various image registration techniques. See the table for median values (%). Conclusions PET-based non-rigid image registration is best suited for image registration of test-retest studies. Assessment of response in SUV is less affected by registration strategy than that in TLG. Research Support CTMM AIRFORC ER -