@phdthesis{Janssen2023,
  author    = {Janßen, Jan Paul},
  title     = {Capabilities of a multi-pinhole SPECT system with two stationary detectors for in vivo imaging in rodents},
  doi       = {10.25972/OPUS-32860},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-328608},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2023},
  abstract  = {Molecular imaging of rats is of great importance for basic and translational research. As a powerful tool in nuclear medicine, SPECT can be used to visualize specific functional processes in the body, such as myocardial perfusion or bone metabolism. Typical applications in laboratory animals are imaging diagnostics or the development of new tracers for clinical use. Innovations have enabled resolutions of up to a quarter of a millimeter with acceptable sensitivity. These advances have recently led to significantly more interest in SPECT both clinically and preclinically. The objective of this thesis was to evaluate the performance of the new U-SPECT5/CT E-Class by MILabs with a dedicated ultra-high resolution multi-pinhole collimator for rats and its potential for in vivo imaging of rats. The unique features of the U-SPECT are the large stationary detectors and the new iterative reconstruction algorithm. In addition, compared to the conventional system, the "E-Class" uses only two detectors instead of three. First, the sensitivity, maximum resolution, and uniformity were determined as performance parameters. Thereafter, CNRs for different activity levels comparable to those of typical in vivo activities were examined. Finally, two example protocols were carried out for imaging with 99mTc-MIBI and 99mTc-HMDP in healthy rats to evaluate the in vivo capabilities. For this purpose, CNR calculations and an image quality assessment were performed. The focus was on image quality as a function of scan time and post-reconstruction filter across a wide range of realistically achievable in vivo conditions. Performance was reasonable compared to other systems in the literature, with a sensitivity of 567 cps/MBq, a maximum resolution of 1.20 mm, and a uniformity of 55.5\%. At the lower activities, resolution in phantom studies decreased to ≥1.80 mm while maintaining good image quality. High-quality bone and myocardial perfusion SPECTs were obtained in rats with a resolution of ≥1.80 mm and ≥2.20 mm, respectively. Although limited sensitivity remains a weakness of SPECT, the U-SPECT5/CT E-Class with the UHR-RM collimator can achieve in vivo results of the highest standard despite the missing third detector. Currently, it is one of the best options for high-resolution radionuclide imaging in rats.},
  subject      = {SPECT},
  language  = {en}
}