A comparison of 18F-FDG gamma camera PET, mammography and ultrasonography in demonstrating primary disease in locally advanced breast cancer

Abstract

Background: Positron emission tomography (PET) imaging using [18F]fluorodeoxyglucose (18F-FDG) is recognized to have a major role in oncological imaging. Over recent years there has been a steady increase in the use of gamma camera PET (GCPET) systems as these are less expensive than dedicated PET scanners and facilitate the full range of nuclear medicine imaging. However, there is ongoing debate about their application and usefulness in the management of oncological patients.

Objectives: To assess the feasibility of GCPET in a nuclear medicine department in a district general hospital remote from a cyclotron, compared with other imaging modalities in demonstrating disease in patients with large or locally advanced breast cancer.

Methods: 18F-FDG was transported by road from a production unit 100 miles from the imaging department. Twenty-five patients (mean age 68 years) with primary breast tumours measuring > or =20 mm on clinical examination were studied. All patients underwent triple assessment prior to PET imaging with an ADAC Solus camera with molecular coincidence detection capability. Histopathology was obtained in 20 cases following surgery.

Results: GCPET detected 24/25 primary breast tumours (sensitivity 96%). This compared with 22/25 (88%) for ultrasound and 15/25 (60%) for mammography. The lesion missed by PET was a grade 1 tumour, 8 mm in size.

Conclusion: In this pilot study GCPET has been shown to be feasible in a district general hospital, enabling a limited on-site PET imaging service to be provided. In the cases studied it was more sensitive than mammography or ultrasonography. GCPET may provide additional information that could be important in planning the management of some patients with breast cancer.