PhD ceremony Mr. C. Wu: Ultra-high-resolution quantitative multi-pinhole small-animal SPECT

PhD ceremony: Mr. C. Wu, 12.45 uur, Academiegebouw, Broerstraat 5, Groningen

Dissertation: Ultra-high-resolution quantitative multi-pinhole small-animal SPECT

Promotor(s): prof. F.J. Beekman, prof. R.A.J.O. Dierckx

Faculty: Medical Sciences

Small-animal single photon emission computed tomography (SPECT) allows imaging the dynamic 3D distribution of radio labeled molecules (“tracers”) in rodents at sub-half-millimeter resolution. This allows e.g. to study function of cell populations non-invasively, and to develop new tracers, pharmaceuticals and clinical imaging procedures.

The thesis first explains the technology of small-animal SPECT and SPECT/computed tomography (CT) including applications in cardiovascular research, and continues with a study on methods for reducing cardiac image blur caused by animal breathing. Furthermore, in order to quantify precisely the amount of tracers in certain locations of animal bodies using their SPECT images, the thesis describes and evaluates a fast and practical method to correct for attenuation of gamma-radiation by tissue on trajectories between the locations of the tracers and SPECT detectors. Finally the influence of the attenuation map inaccuracy on the quantitative accuracy of reconstructed tracer uptake in SPECT images has been thoroughly investigated and discussed.

The research shows that highly quantitative (uncertainty < 2%) small-animal SPECT imaging can be achieved, which was previously thought to be possible for positron emission tomography (PET) only. Together with its ultra-high resolution (quarter mm), small-animal SPECT reveals possibilities for many novel preclinical applications with a broad selection of SPECT tracers, which are likely to benefit research into diseases and drug exploration.