The role of PET scanning in radiotherapy

Positron emission tomography (PET) is a powerful and versatile imaging tool that offers the unique opportunity to visualise and measure pathophysiology and key biological parameters that influence disease diagnosis, development and outcome. The field of PET has previously been dominated by studies in neuroscience research, but over the last 10 years with the development of whole-body scanners, fluourine-18-labelled fluorodeoxyglucose (F-FDG) PET for staging of tumours has dominated in the clinical oncology area. More recently, the role of PET in the radiotherapy management of patients has been investigated. To measure biological parameters in vivo, PET utilises biological molecules such as water, amino acids, metabolic precursors and hormones labelled with positron-emitting radionucleotides such as F, C, N and O. Therapeutic drug compounds can also be radioactively labelled. Highresolution images produced by PET allow the presence of such compounds to be accurately monitored in the patients’ body, and highly sensitive and specific biological measurements can be made [1]. Consequently, PET is positioned as the ideal tool to provide clinically relevant information. Further research and development of PET methods will contribute to an increased understanding of tumour biology and the complex biological processes that contribute to chemotherapy and radiotherapy resistance. PET is therefore predicted to have a significant impact on our ability to investigate disease processes and to improve and individualise anticancer therapies.