Dual-tracer multiparametric imaging with a long-axial field-of-view PET to better characterize cancer

University Of Pennsylvania, Philadelphia PA

Investigators

Abstract

PROJECT SUMMARY/ABSTRACT Numerous new PET radiotracers introduced in the past decade have improved our ability to non-invasively detect disease and characterize tumor biology. These new tracers complement imaging with FDG, a marker of glucose metabolism widely used in the clinic. The integration of these tracers into clinical practice has transformed the treatment of many diseases, ushering in a new era of precision medicine guided by molecular imaging. Modern PET protocols, though, limit our ability to fully exploit this new tracer technology. As a PET scanner cannot distinguish between tracers, different tracers must be imaged on separate days to allow for decay of the first prior to imaging the second. This necessary delay hampers the radiologist’s ability to render a timely unified diagnosis of the two image datasets, inconveniences the patient, needlessly consumes resources, and stresses our already strained healthcare system. In this project, we will develop novel methods to image two PET tracers with different molecular targets back-to-back, in single imaging session, using a novel whole-body PET scanner, the PennPET Explorer. Using this whole-body scanner, we will study protocols where a first tracer is injected at a lower dose and a second tracer at higher dose, without the patient leaving the scanner, with images obtained in the same imaging session. We will study two pairs of tracers as representative models for this new class of protocols for dual-tracer PET. In Aim 1, we will develop protocols to image Fluoroglutamine, a research radiotracer of glutamine metabolism, in combination with FDG in women with breast cancer. This will serve as a prototype for quantification with a pair of research radiotracers, where kinetic analysis is implemented. In Aim 2, we will develop protocols to image two FDA approve radiotracers with dual-tracer PET. Aim 2 will image FDG paired with Fluoroestradiol (FES), a clinically approved radiotracer that measures estrogen receptor (ER) expression in breast cancer. In this aim, we will develop a delayed (static) dual-tracer FES/FDG image protocol ready for immediate clinical translation, noting the clinical need to interpret FES-PET in the contact of FDG-PET. We will also develop novel 4D radiomic image analysis techniques to analyze the robust dual-tracer data collected in this aim to predict response to ER-targeted therapy, a currently unmet clinical need. In the Aim 3, we will translate the dual-tracer protocols developed in the first two aims to scanners with shorter axial field-of-views, including long-axial field-of-view scanners with varying lengths that are now clinically available as well as standard-axial field-of-view scanners that currently populate image centers across the country. As a result, the protocols developed will apply to the entire range of available scanners, increasing the overall impact of this proposal. The outcomes of this proposal will advance the capabilities of PET—optimizing the utilization of new radiotracers—to characterize and guide treatment in oncology.