Quantitative analysis of Cherenkov emission imaging

Abstract: Cherenkov emission imaging is a new optical imaging technique in nuclear medicine that takes advantage of the fact that most positron emitting radionuclides have a sufficient energy to produce Cherenkov photons. The Cherenkov photons can then be detected with sensitive CCD camera systems. Due to the recent demonstration of detectable amounts of Cherenkov light escaping from nuclide bearing mice the interest in Cherenkov radiation has increased. The demonstrated results of animal studies give an implication that it is possible to use the CR phenomenon for medical research and possibly for clinical purposes. A large plethora of clinically used radiopharmaceuticals for imaging and therapy can be imaged with Cherenkov luminescence imaging (CLI). This means that it is possible to use the method to follow the distribution of these radiopharmaceuticals in vivo, thereby the method could possibly be used as a dosimetry tool in systemic radiation therapy (SRT). Several research groups have investigated the correlation between CLI and PET-imaging, and an excellent correlation between the bio-distributions obtained with the two methods has been found. Compared to currently used imaging methods such as PET and SPECT, CLI is a simple method which makes it interesting for e.g. screening purposes. The equipment needed for CLI is less expensive than PET and SPECT equipment, meaning that it would be a good alternate method for smaller laboratories with a restricted budget. The aim of this study is to investigate the possibility for quantitative measurements and to quantitatively analyse the use of Cherenkov emission imaging in optical phantoms and pre-clinical animal models. This study includes several experiments where the relation between different optical properties of the studied media and the emitted Cherenkov radiation is investigated. The results shown by the work in this thesis are in good agreement with the theoretical expectations and results shown by other research groups. Cherenkov emission imaging can be used for radionuclide localization in preclinical animal studies, meaning that the method could be used to study selective uptake in superficial tumours. The CLI method could provide us with a low-cost high-throughput alternative to preclinical PET.