Can dual-headed F-18-FDG SPET imaging reliably supersede PET in clinical oncology? A comparative study in lung and gastrointestinal tract cancer

In this study, we prospectively compared the sensitivity of PET and planar SPET (collimated gamma camera) F-18-FDG imaging in patients with lung and g astrointestinal tract cancer and analysed their respective impact on patien t management. Twenty-eight patients with lung cancer and 14 with gastrointe stinal tract tumours were scanned on the same day with a PET and a collimat ed planar SPET gamma camera. The planar SPET procedure consisted of whole-b ody planar views and a tomographic acquisition centred over the torso or th e abdomen, with the total imaging time within the same range as the whole-b ody PET procedure. The staging of lung cancer patients was accurate in 86% with PET and 64% with planar SPET. Planar SPET would have led to inappropri ate therapeutic decisons in 8 of 28 patients, mainly due to undectected dis tant metastases. In patients with suspected gastrointestinal tract cancer, planar SPET identified 7 of 15 (47%) proven tumour sites, whereas PET ident ified 14 of 15 (93%). Our results suggest that collimated planar SPET camer as are not a substitute for dedicated PET scanners. The sensitivity for the detection of tumours is unacceptably low and can impair patient management . The use of multiple tomographic acquisitions could improve the sensitivit y but would require a longer scanning time. ((C) 1998 Lippincott Williams & Wilkins).