Assessment of tumour size in PET/CT lung cancer studies: PET- and CT-based methods compared to pathology

• Published in: EJNMMI research 2012-10, Vol.2 (1), p.56-56, Article 56
• Main Authors: Cheebsumon, Patsuree, Boellaard, Ronald, de Ruysscher, Dirk, van Elmpt, Wouter, van Baardwijk, Angela, Yaqub, Maqsood, Hoekstra, Otto S, Comans, Emile FI, Lammertsma, Adriaan A, van Velden, Floris HP
• Format: Article
• Language: English
• Subjects: Cardiac Imaging; Imaging; Medicine; Medicine & Public Health; Nuclear Medicine; Oncology; Original Research; Orthopedics; Radiology
• ISSN: 2191-219X; 2191-219X
• DOI: 10.1186/2191-219X-2-56

Background Positron emission tomography (PET) may be useful for defining the gross tumour volume for radiation treatment planning and for response monitoring of non-small cell lung cancer (NSCLC) patients. The purpose of this study was to compare tumour sizes obtained from CT- and various more commonly available PET-based tumour delineation methods to pathology findings. Methods Retrospective non-respiratory gated whole body [ 18 F]-fluoro-2-deoxy-D-glucose PET/CT studies from 19 NSCLC patients were used. Several (semi-)automatic PET-based tumour delineation methods and manual CT-based delineation were used to assess the maximum tumour diameter. Results 50%, adaptive 41% threshold-based and contrast-oriented delineation methods showed good agreement with pathology after removing two outliers (R 2 =0.82). An absolute SUV threshold of 2.5 also showed a good agreement with pathology after the removal of 5 outliers (R 2 : 0.79), but showed a significant overestimation in the maximum diameter (19.8 mm, p0.62) with pathology. Although adaptive 70% threshold-based methods showed underestimation compared to pathology (36%), it provided the best precision (SD: 14%) together with good correlation (R 2 =0.81). Good correlation between CT delineation and pathology was observed (R 2 =0.77). However, CT delineation showed a significant overestimation compared with pathology (3.8 mm, p