Molecular imaging in oncology: Challenges and opportunities in the twenty-first century

Abstract

Each improvement of radionuclide imaging modalities (positron emission tomography, PET; single-photon emission computed tomography, SPECT) is dependent upon the development of tumor-specific radiopharmaceuticals with enhanced tumor specificity. Applications of molecular targets for cancer imaging, therapy, and prevention that use generator-produced isotopes are the major focus of ongoing research projects. 99mTc (technetium-99 m,), 68Ga (gallium-68), and 188Re (rhenium-188) are generator-produced isotopes, which are readily accessible and affordable. While 99mTc (t1/2 = 6 h, 140 keV) is used for SPECT, 68Ga (t1/2 = 68 min, 511 keV) labeling is for PET, and both are intended to image molecular targets to determine therapeutic dosage, monitor tumor response to treatment, and establish differential diagnoses. 188Re (t1/2 = 16.9 h, 2.1 MeV) is a therapeutic radionuclide, which can be used to target tumors and deliver lethal radiation resulting from high-energy Β− emissions. The present chapter discusses challenges and opportunities in molecular imaging, involving drug discovery, validation, intellectual property, licensing, and regulatory compliance.