Abstracts Category : Other

Quantitative Accuracy of Iterative ReconstructionAlgorithms in Positron Emission Tomography

by Ian Armstrong

Positron Emission Tomography (PET) plays anessential role in the management of patients with cancer. It isused to detect and characterise malignancy as well as monitorresponse to therapy. PET is a quantitative imaging tool, producingimages that quantify the uptake of a radiotracer that has beenadministered to the patient. The most common measure of uptakederived from the image is known as a Standardised Uptake Value(SUV). Data acquired on the scanner is processed to produce imagesthat are reported by clinicians. This task is known as imagereconstruction and uses computational algorithms to process thescan data. The last decade has seen substantial development ofthese algorithms, which have become commercially available:modelling of the scanner spatial resolution (resolution modelling)and time of flight (TOF). The Biograph mCT was the first scannerfrom Siemens Healthcare to feature these two algorithms and thescanner at Central Manchester University Hospitals was the firstBiograph mCT to go live in the UK. This PhD project, sponsored bySiemens Healthcare, aims to evaluate the effect of these algorithmson SUV in routine oncology imaging through a combination of phantomand patient studies.Resolution modelling improved visualisation ofsmall objects and resulted in significant increases of uptakemeasurements. This may pose a challenge to clinicians wheninterpreting established uptake metrics that are used as anindication of disease status. Resolution modelling reduced thevariability of SUV. This improved precision is particularlybeneficial when assessing SUV changes during therapy monitoring.TOFwas shown to reduce image noise with a conservation of FDG uptakemeasurements, relative to non-TOF algorithms. As a result of thiswork, TOF has been used routinely since mid-2014 at the CMUHdepartment. This has facilitated a reduction of patient and staffradiation dose and an increase of 100 scans performed each year inthe department.Advisors/Committee Members: WILLIAMS, HEATHER HA, Williams, Heather, Matthews, Julian.