Implementations of dynamic source modelling in SPECT/CT simulations with gate for oncological imaging

Medical imaging systems have an important place in the clinical diagnosis and treatment. In terms of health, radiology and nuclear medicine departments are the units that use the radiation for diagnostic purposes, and the radiotherapy departments are the ones use it in the treatment purposes. The main purpose of medical ionizing radiation applications is to obtain more sensitive and accurate images. In general, medical imaging systems work with X-rays and ionized radiation sources. Computerised tomography is a method of radiological diagnosis that allows us to obtain cross-sectional views of regions of the body that is under examination with applying X-rays. SPECT that is a 3D imaging method with scintigraphy of images, aimed to diagnose physiopathological and functional changes in almost all organs and systems, especially oncological diseases using radionuclide or radiopharmaceuticals. The fact that SPECT and CT are in a single system gives spatial morphological and pathological correlation of abnormal metabolic activity. This ensures that images are recorded together at the most efficient level and images are obtained from both systems with a single review. In this study, SPECT / CT simulations for cylindrical voxel phantoms were performed using the GATE (PET & SPECT simulator library) developed under the Geant 4 simulation software created by the European Center for Nuclear Research (CERN). In the virtual installations, activity differences, displacements and screening effects of the tissues were investigated; Energy histograms and dose curves are obtained by analyzing virtual data with ROOT software. After analysing the obtained data statistically, the results are presented with the interpretation of the differences that may have significant effects for some values. Keywords: Spect, BT, Hybrid Imaging, Geant4, GATE