FDG-PET/CT integration: impact on tumour localization and dose volume histograms in radiation therapy

Conventional radiotherapy for non-small cell lung cancer (NSCLC) is often unable to achieve local control. For this reason, 3DCRT with dose escalation is being investigated as a means of improving outcome. It is essential to accurately define the gross tumour volume (GTV) for 3DCRT to succeed. Unfortunately, anatomic imaging techniques such as CT or MRI are often unable to distinguish tumour from normal tissue. Functional imaging with ¹⁸F-FDG PET has the potential to define the GTV more accurately. A prospective study of the use of FDG-hybrid-PET images fused to CT simulation images in radiotherapy treatment planning for NSCLC is described. In a significant fraction of cases, the addition of functional information produces dramatic changes both in the GTV and in dose volume histograms for normal tissues