Future Directions of PET and Molecular Imaging and Therapy with an Emphasis on Melanoma and Sarcoma

Abstract

Although FDG PET imaging has been successful in the staging and follow-up of malignancies, including melanomas and sarcomas, there are still some important areas where it is still limited. Historically, many different tracers were used with SPECT imaging which provided an improvement over other cross-sectional imaging modalities, but certainly FDG PET has replaced most of those prior indications. Nevertheless, there continues to be development of more sophisticated tracers targeting receptors and metabolic processes, which potentially improve overall accuracy of staging. Many of these molecular imaging methodologies are used in different malignancies, but some are more specific for melanomas and sarcomas. Combined with the identification of disease with molecular imaging to identify appropriate targets of disease, the field of radiotheragnostics is emerging as a viable modality in providing another approach to the treatment of advanced disease. Here, the molecular targeting radiopharmaceuticals can be radiolabelled with other radioisotopes, which, when delivered in sufficient quantities, can also provide therapeutic benefit. Other fields such as optical imaging and radiomics are also emerging which could not only improve the initial noninvasive evaluation of patients but also provide in vivo assistance in guiding surgical management. Ultimately these are the basis for photodynamic therapy, which can complement radiotheragnostics and other treatment approaches.