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Positron emission tomography (PET) is a non-invasive molecular imaging technique using positron-emitting radioisotopes to study functional processes within the body. High resolution PET scanners designed for imaging rodents and non-human primates are now commonplace in preclinical research. Brain imaging in this context, with motion compensation, can potentially enhance the usefulness of PET by avoiding confounds due to anaesthetic drugs and enabling freely moving animals to be imaged during normal and evoked behaviours. Due to the frequent and rapid motion exhibited by alert, awake animals, optimal motion correction requires frequently sampled pose information and precise synchronisation of these data with events in the PET coincidence data stream. Motion measurements should also be as accurate as possible to avoid degrading the excellent spatial resolution provided by state-of-the-art scanners. Here we describe and validate methods for optimised motion tracking suited to the correction of motion in awake rats. A hardware based synchronisation approach is used to achieve temporal alignment of tracker and scanner data to within 10 ms. We explored the impact of motion tracker synchronisation error, pose sampling rate, rate of motion, and marker size on motion correction accuracy. With accurate synchronisation (<100 ms error), a sampling rate of >20 Hz, and a small head marker suitable for awake animal studies, excellent motion correction results were obtained in phantom studies with a variety of continuous motion patterns, including realistic rat motion (<5% bias in mean concentration). Feasibility of the approach was also demonstrated in an awake rat study. We conclude that motion tracking parameters needed for effective motion correction in preclinical brain imaging of awake rats are achievable in the laboratory setting. This could broaden the scope of animal experiments currently possible with PET.

Item Type:	Refereed Article
Keywords:	brain function, feasibility study, functional assessment, movement perception, nervous system parameters, perceptive discrimination, positron emission tomography, quantitative analysis
Research Division:	Physical Sciences
Research Group:	Medical and biological physics
Research Field:	Medical physics
Objective Division:	Health
Objective Group:	Other health
Objective Field:	Other health not elsewhere classified
UTAS Author:	Baldock, C (Professor Clive Baldock)
ID Code:	116139
Year Published:	2011
Web of Science® Times Cited:	56
Deposited By:	Strategic Research Funding
Deposited On:	2017-05-02
Last Modified:	2017-11-06
Downloads:	128 View Download Statistics