Development of an MR-compatible SPECT system based on energy resolved photon counting detectors

Magnetic Resonance - Single\rPhoton Emission Computed Tomography (MR-SPECT);Energy resolved photon counting detector;Geometry calibration;Reconstruction

Cai, Liang ; Meng ; Ling Jian

关键词: Magnetic Resonance - Single\rPhoton Emission Computed Tomography (MR-SPECT);    Energy resolved photon counting detector;    Geometry calibration;    Reconstruction;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/18522/Cai_Liang.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Nuclear medicine is playing an important role in the clinical diagnosis and therapy. Single Photon Emission Computed Tomography (SPECT) is one of the most important nuclear imaging modalities, and it gives the functional imaging of the region of interest. MR can provide the anatomical imaging and enjoys better soft tissue contrast comparing to Computed Tomography. In this thesis, a MR compatible SPECT system is developed and the performance of this system is evaluated. This SPECT system is based on novel energy-resolved photon counting (ERPC) detectors we have recently developed for gamma ray imaging applications. The ERPC detector has basic modular configuration that offers an overall detection area of 4.5 cm×4.5 cm, comprising of eight CdTe/CMOS detector hybrids. Each hybrid has a CdTe detector of 11 mm×22 mm bump-bonded onto a dedicated readout ASIC that has 32×64 readout pixels with 350μm pitch size. The 1mm and 2mm thickness CdTe detector have both been developed. This configuration offers a very-high spatial resolution of around 350μm and an excellent energy resolution of around 3~4 keV at 140 keV. The prototype SPECT system that consists of two or four ERPC detectors is mounted on a system gantry rotating around a horizontal axis. The detectors are coupled to apertures with differently sized pinholes. In order to utilize the imaging information provided by the ERPC detector, we have developed a comprehensive system modeling and calibration method that accounts for the irregular shapes and physical details in the collimation apertures. Besides this, a detailed charge collection inside strong magnetic field is developed by J.W Tan in our group, and a MR correction model based on this model is used to reconstruct SPECT image inside strong magnetic field. Detailed system design and experimental procedures will be described in this thesis.