Biography
Biography: Anca-Ligia Grosu
Abstract
In radiation therapy (RT) staging, treatment planning, monitoring and evaluation of response are traditionally based on computed tomography (CT) and magnetic resonance imaging (MRI). These radiological investigations have the significant advantage to show the anatomy with a high resolution, being also called anatomical imaging. In recent years, so called biological imaging methods which visualize metabolic pathways have been developed. These methods offer complementary imaging of various aspects of tumor biology. To date, the most prominent biological imaging system in use is positron emission tomography (PET), whose diagnostic properties have clinically been evaluated for years. The first rationale for using PET in target volume delineation for radiation treatment planning is the higher sensitivity and specificity of PET for tumor tissue in comparison to CT and MRI in some tumor entities. This has been demonstrated in many studies evaluating the results of PET with the results of radiological investigations and histology. The hypothesis tested in these studies was that using PET in addition to CT and/or MRI allows tumor tissue detection with a higher accuracy. The second rationale for integrating PET in the process of radiation treatment planning is the ability of PET to visualize biological pathways, which can be targeted by radiation therapy. The visualization of hypoxia, angiogenesis, proliferation, apoptosis, receptor expression, gene expression etc., leads to the identification of different characteristics of the tumors of different sub areas of the gross tumor mass which can be individually targeted. The aim of this presentation is to discuss the valences and implications of PET in RT. We will focus our evaluation on the following topics: The role of biological imaging for tumor tissue detection/delineation of the gross tumor volume (GTV) and for the visualization of heterogeneous tumor biology. We will discuss the role of FDG-PET and hypoxia-PET (FMISO-PET) in lung and head and neck cancer, the impact of amino acids (AA)-PET in target volume delineation of brain tumors and the role of Choline, Bombesine and PSMA-PET in prostate cancer. Furthermore, we will discuss the impact of animal-PET in the visualization of glioblastoma tumor stem cells. We conclude that, regarding treatment planning in radiotherapy, PET offers advantages in terms of tumor delineation and the description of biological processes.