Quantitative oncology molecular analysis suite: ACCURATE

Aim: Quantitative analysis of PET studies requires standardized and advanced image processing and analysis tools. The aim of this work was to develop a software tool that provides the user with a series of (semi-)automated image analysis and PET based segmentation methods to quantitatively analyse tracer uptake in oncology and lymphoma PET/CT studies. Methods and results: ACCURATE is developed in IDL version 8.4 (Harris Geospatial Solutions, Bloomfield, USA) and runs under the IDL virtual machine, which is freely available. ACCURATE allows for DICOM input of both PET and CT data. It includes several image processing steps such as rebinning/resampling, cropping and smoothing. After loading and processing PET/CT images, lesions can be delineated using a range of segmentation

Methods: fixed sized segmentations (squares, cubes, circles, spheres), manual free hand segmentation, fixed SUV thresholds; % of SUVmax or SUVpeak isocontours with or without local contrast correction; a gradient based method and 2 majority vote based implementations. During the extraction of quantitative uptake features, such as SUVmax, SUVpeak, SUVmean, metabolic volume and total lesion glycolysis and various other 1^st order statistics, 4 different partial volume correction methods can be applied. Moreover the tool can provide the user with more than 250 radiomics output features, with either relative and/or fixed SUV binning. In addition, optimized semi-automated workflows for quickly and easily assessing total tumor burden are available. The tool has also functionality to extract time activity curves from dynamic PET studies which can be used for full quantitative kinetic analysis. Finally, the tool can deal with correct SUV calculations for long-lived isotopes, i.e. it allows for decay correction over multiple days. Several data sanity checks have been incorporated, such as swapping of weight and height and other data plausibility checks. Liver uptake can be quickly previewed and verified. Results obtained with ACCURATE have been verified using simulations, phantom studies and a head-to-head comparison with other (commercially available) image analysis tools using clinical datasets. Conclusions: ACCURATE allows for quick and reliable analysis of (FDG) PET/CT studies using state of the art segmentation and image processing methods. The tool is particularly suited for exploring the effects of image processing, segmentation strategies and partial volume corrections on the quantitative evaluation of oncology or lymphoma PET studies. New functionality beyond state the art will be continuously added. The tools will be made freely available (r.boellaard@vumc.nl)