Poster abstracts

Poster number 37 submitted by Xiaoli Liu

Evaluation of Impact of Region-of-interests (ROIs) on Tumor Quantification and Therapy Response Assessment in 18F-FDG PET/CT with PERCIST

Xiaoli Liu (Biophysics, The Ohio State University), Jun Zhang (Radiology, The Ohio State University), Nathan Hall (Radiology, The Ohio State University), Michael Knopp (Radiology, The Ohio State University)

Abstract:
This study aimed to quantitatively evaluate the impact of ROI definitions on tumor assessment and therapy response in oncology 18F-FDG PET/CT with PERCISIT.53 PET/CT data sets of 20 patients before and after therapy were selected from clinical care whole-body scans 75±10 minutes post injecting 14±1mCi 18F-FDG on a Gemini TF 64 system (Philips Healthcare). PERCIST assessment however with varying with sizes of ROI (1, 2, 5 and 10cc) placement was used for tumor delineation, SUV lean (SUL) peak determination and therapy response assessment. Results were analyzed on Extended Brilliance Workspace and used ANOVA for statistical significance assessment at p<0.05.SUL peak decreased as an increase of the sizes of ROI and were very sensitive to ROI changes comparing to the standard 1cc ROI of PERCIST (p=<0.03). For therapy response, it revealed an individually bi-linear % change (increased and/or decreased) of SUL peak before and after therapy as well as an overall decreased % change as an increase of ROI sizes with a turning point of ROI=2cc. For larger ROIs great than 2cc, the % change became smaller (1cc: 41%, 2cc: 39%, 5cc: 34% and 10cc: 29%).In conclusion,this study investigated the impact of ROI sizes on SUL peak and its impact on PERCIST based therapy response

Keywords: SUL, ROI, PERCIST