Repetitive Functional Imaging in Locally Advanced Cervical Cancer

Background: The Apparent Diffusion Coefficient (ADC) acquired by Diffusion Weighted Imaging (DWI-MR) has been shown to correlate with cellular density. The ADC is indicative of Gross Tumour Volume (GTV), and preliminary data shows that the dynamics of DWI volumes during treatment (shrinkage) as well as dose to DWI volumes has impact on treatment outcome. Hypoxic tumour cells within the primary tumour have been identified to have prognostic importance for local control Tumour hypoxia is caused by insufficiency of the tumour vasculature leading to both chronic diffusion limited and acute flow limited hypoxia. Radioresistant hypoxic cells diminish the rate of local control, and the hypoxia driven increase in metastatic potential of the tumour and lowers the rate of distant disease control. Functional imaging has the potential to visualise radioresistant tumour subvolumes. PET scanning (18F-FAZA) is hypothesized to visualise hypoxic tumour subvolumes, and dynamic contrast enhanced (DCE) MR imaging has been used to quantify the extent of poor perfusion regions within cervical tumours. Objectives: Primary: Sensitivity and specificity of functional imaging (18F-FAZA PET (optional), T1w, T2w, DWI-MRI and DCE-MRI) to identify tumours with good and bad response to radio-chemotherapy Secondary: Determining whether there are differences in bias between centre. The difference in bias will be assessed for the T1 and T2 scans and the Ktrans and ADC maps.