Clinical PET Imaging – An Asian Perspective

Abstract

Positron emission tomography (PET) has entered a new phase of development since a major technological breakthrough in 2000. Combined with computed tomography (CT), the second-generation PET-CT scanner is now able to obtain both functional and anatomical information of the whole body from a single study. Its application in oncology has become one of the standard imaging modalities in diagnosis, staging and monitoring therapeutic efficacy. It is well known that the Asian and Western populations have their own characteristic disease spectrum and cancer incidence. Although changes in diet and life-style have narrowed the differences in the last decade, there remains moderate divergence and disparities in cancer pattern and priority of resource allocation in different countries. It is known that F-18 fluorodeoxyglucose (FDG) is the most widely used radiopharmaceutical in PET imaging and it has been confirmed valuable in a variety of cancer types such as lung, colorectum, oesophagus, head and neck (including nasopharyngeal carcinoma), breast, pancreas, lymphoma, melanoma, cholangiocarcinoma and many types of sarcoma. Some cancer types, however, are less sensitive to FDG-PET detection and these include hepatocellular carcinoma, urological carcinoma, gastric malignancy, mucinous and clear-cell gastrointestinal tumours, neuroendocrine tumours and well-differentiated thyroid cancers. Some of these less sensitive cancer types are more prevalent in the Asian population than the Euro-American population and are, therefore, more frequently encountered as false negative cases in FDG-PET imaging. On the other hand, Asian countries are more prevalent in diseases such as tuberculosis and the chance of having false positive FDG-PET cases is higher than the Euro-American countries in the evaluation of lung and other cancers. From the Asian perspective, we are more susceptible to having a higher chance of both false negative and false positive FDG-PET cases. Thus, there is a stronger emphasis of research on new drugs to overcome the limitations of FDG. The use of PET imaging as a diagnostic tool has gained wide acceptance in Asia during the past few years and its clinical utility is expected to continue to rise. More research on other PET radiopharmaceuticals should therefore be given a higher priority along side with the maturation of scanning technology.