THE APPLICATION OF POSITRON EMISSION TOMOGRAPHY IN RADIOTHERAPY TREATMENT PLANNING

Abstract

Positron emission tomography (PET) is a molecular imaging technique thatprovides a direct and accurate evaluation of tissue function in vivo. PET of theglucose analogue 18F-fluoro-deoxy-glucose, is increasingly in use to aid ingross target volume delineation in radiotherapy treatment planning (RTP)where it shows reduced inter-observer variability. The aim of this thesis wasto develop and investigate a new technique for delineating PET-GTV withsufficient accuracy for RTP. A new technique, volume and contrast adjustedthresholding (VCAT), has been developed to automatically determine theoptimum threshold value that measures the true volume on PET images. Theaccuracy was investigated in spherical and irregular lesions in phantoms usingboth iterative and filtered back-projection reconstructions and different image noise levels. The accuracy of delineation for the irregular lesions was assessed by comparison with CT using the Dice Similarity Coefficient and Euclidean Distance Transformation. A preliminarily investigation of implementing the newly developed technique in patients was carried out. VCAT proved to determine volumes and delineate tumour boundaries on PET/CT well within the acceptable errors for radiotherapy treatment planning irrespective of lesion contrast, image noise level and reconstruction technique.

Date of Award	1 Aug 2011
Original language	English
Awarding Institution	The University of Manchester
Supervisor	David Hastings (Supervisor) & Carl Rowbottom (Supervisor)