ABSTRACT
I. Introduction 3
II. Radionuclides for PET and SPECT Molecular Imaging Probes 6
III. Radiotracers for Molecular Imaging 12
A. Tumor Metabolism 12
B. Tumor Proliferation 14
C. Tumor Hypoxia 16
D. Tumor Receptors 18
SST Receptors 18
VIP Receptors 20
Other Receptors 21
E. Reporter Genes 22
IV. Summary 24
References 25
I. Introduction
The term “molecular imaging” can be broadly defined as the in vivo character-
ization and measurement of biological processes at the cellular and subcellular
(molecular) levels (1). The traditional approach for diagnosing disease is
largely based on assessing anatomical and physiological changes that are late
manifestations of molecular changes. However, advances in molecular and
cellular biology techniques (manipulation of nucleic acids, DNA sequencing,
reverse transcription, polymerase chain reaction, etc.) allow development of
novel tools, reagents, and methods to image-specific pathways in vivo, particu-
larly those involved in disease processes (2-8). The completion of the first
draft of the human genome (9) and the subsequent developments in proteomics
are expected to lead to new understanding of the disease processes and to new
medical therapies and diagnostics previously not imagined.
