Applications of Positron Emission Tomography in Radiation Treatment

J. Daniel Bourland, PhD

Associate Professor and Head, Physics Research and Education

Department of Radiation Oncology

Wake Forest University, Winston-Salem, North Carolina, USA

bourland@wfubmc.edu

Positron Emission Tomography (PET) uses coincidence photon detection to image physiology and biology through the in-vivo distribution of short-lived, positron-emitting radionuclides. PET imaging can show focal and distributed regions of cancer and its metastases. Its uses in oncology include diagnosis, staging, and disease monitoring. Quantitative uses of PET may include radiation target definition and evaluation of treatment response.

F-18-labled Fluoro-deoxyglucose (FDG) is the most common PET imaging agent and shows regions of active glucose metabolism such as cancer, metastases, and inflammation. PET agents other than FDG, for instance F-18 Misonidazole and C-11-labeled amino acids, show potential to image tumor biology like hypoxia and cell proliferation. PET has relatively coarse spatial resolution but high sensitivity for cancer detection. There are now hybrid PET-CT units that can be used as radiation treatment simulators, to enable CT-based attenuation corrections and a co-registered PET-CT dataset. The Standardized Uptake Value (SUV), a normalized intensity measure, may be useful for quantifying disease state and radiation target delineation.

PET physics, contributions and limitations of FDG and non-FDG PET for oncology imaging, and quantitative aspects for PET-based radiation target definition are reviewed. This presentation is intended for both imaging and radiation oncology physicists.

Research sponsored in part by Varian Medical Systems and GE Healthcare.