TOTAL BODY PET [TB-PET]: A DESIRE OR NEED?

Abstract

In current era positron imaging tomography (PET) with computerized tomography (CT) or magnetic resonance imaging (MRI) are the most widely used hybrid imaging modalities in clinical arena. In fact, it has revolutionized the staging, restaging, selection of therapy and response assessment in various malignancies. However, we must be cognizant of PET’s journey which started from a research laboratory of Massachusetts General Hospital, USA in 1951 to 1999 when first commercial hybrid PET/CT was introduced by Townsend and team in USA and Time Magazinecalled it medical invention of the year in 2000.PET with CT and MRI is believed the most sensitive hybrid technique available to study physiology, metabolism, and various molecular pathways in human being. However, one must not forget the limitations of PET imaging like extremely poor sensitivity (<1%), limited resolution due to low signal to noise ratio (SNR), long acquisition times and concerns about radiation exposure. Two major factors which govern the poor sensitivity of existing PET scanners are (1) 85-90% of body is outside of field of view (FOV) and no signal is from these regions is collected; (2) only 3-5% of signals