Clinical indications for positron emission tomography (PET) scanning.

Address for Correspondence: Dr Anthony S W Goh, Department of Nuclear Medicine, Singapore General Hospital, Outram Road, Singapore 169608. Introduction The purpose of these guidelines is to provide a broad framework for clinicians considering the use of positron emission tomography (PET) scanning for their patients. PET imaging is a rapidly evolving field, with ongoing developments in imaging technology, radiochemistry, isotope production, animal research and clinical applications. There is a need for regular review of these guidelines, to incorporate new evidence and results of scientific research. Like most diagnostic tests, meta-analyses or systematic reviews are not available for PET in every clinical application. Nonetheless, clinical practice should be guided by the best available evidence. Whilst some of the following recommendations are based on mature scientific evidence, others simply represent the current consensus of experts in this field. Most of the published data on PET scanning refer to studies using traditional PET scanners. Combined PETcomputed tomography (CT) scanners became commercially available in 2002, and a wealth of new data will emerge over the next few years on the incremental value of fusing PET with CT images. Preliminary experience suggests a further enhancement of diagnostic accuracy, impact on patient management and outcome, and extension of useful clinical applications, particularly in oncology practice. As clinical PET services were introduced in Singapore only in mid-2003, all the currently installed scanners are PET-CT devices. New PET radiotracer compounds will also emerge from experimental use into routine clinical application. Future updates to these guidelines will need to keep pace with these developments. In addition, as PET technology has spread more recently in Asian countries, more scientific data relevant to our disease context will need to be sought, e.g. for hepatocellular and nasopharyngeal carcinoma. Local research into these areas should therefore be encouraged. It is not possible to be dogmatic or prescriptive about the role of PET in a given clinical situation, as this may depend on clinical factors, socio-economic circumstances, patient attitudes and other factors. These recommendations should therefore not be interpreted as mandatory for compliance in every stated clinical situation. For ease of reference, the recommendations have been classified into 3 categories: ** Useful application for clinical PET imaging. * Potentially useful application – not indicated routinely, but may be helpful in individual cases, or there is currently limited data to prove costeffectiveness. # Not recommended at present. Unless otherwise stated, routine clinical PET imaging is deemed to be performed with the glucose analog 18F-FDG. However, in certain situations, other PET radiotracers are needed, to visualise other metabolic processes. These are not yet routinely available at most clinical PET sites (including those in Singapore). The following recommendations are intended as a guide for physician referral and patient selection for clinical PET imaging. For more details on the scientific evidence, the reader is advised to refer to the publications in the references section.