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Title: Motion correction in nuclear medicine imaging
Author: Darwesh, Reem
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2013
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Patient motion either internal (organ motion) or external (body movement) can produce artefacts that can adversely affect nuclear medicine imaging. Motion artefacts can impair diagnostic information and potentially affect the image findings and prognosis for patients. The goal of this work was to investigate the effect of motion on nuclear medicine imaging and to improve image quality, lesion detectability, and tumour volume delineation by applying motion correction techniques. To investigate the effects of motion under controlled simulated conditions, a three dimensional phantom drive system was designed and constructed suitable for use with planar, SPECT, PET and CT scanners. The system was used with a range of nuclear medicine phantoms for testing proof of principle with planar, SPECT and PET imaging prior to undertake further work involving patients. Planar phantom and patient 99mTc_DMSA studies demonstrated improvements in image quality by the application of motion correction techniques. A comparison between the motion correction software using dynamic frame and list mode data showed that "MOCO" software with the use of the list mode data produced the best quantification results with phantom data, whereas determining the best approach was more difficult with patient data. The potential of using list mode data as an improved method of combining data into frames for subsequent analysis was demonstrated. Motion correction techniques would appear to offer great potential in lung imaging. Respiratory gated SPECT phantom studies have been carried out to simulate the visualisation of small defects in the lung. The CNRs and alternative free response receiver operating characteristic (AFROC) analysis have demonstrated that summing the gated data after the application of motion correction software significantly improved image quality, observer confidence and small defect detectability (less than 20 mm, p=O.0002). The results of these studies have shown the promising role of "MCFLIRT" software as a motion correction tool with gated SPECT data. Tumour volume delineation was investigated on PET images both with and without motion. The accuracy and consistency of the gradient-based software method for segmentation in PET images, which is commercially available from Mimvista Ltd was investigated. The results of comparing the measured volumes to the true volumes indicated significant differences (p=O.0005). It was found that the Signal:Background ratio and registering the PET to the CT data have significant effects on volume measurements, whereas, the effect of using different grey scale and plane of orientation were not found to have significant effects on the volume measurement. Motion correction techniques also showed to be potentially beneficial in PET imaging. Improvement in volume measurement as a result of summing the motion corrected gated data was demonstrated. The results of these studies have also shown the promising role of "MCFLIRT" as a motion correction tool with gated PET data.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available