Single photon emission computed tomography (SPECT) is a nuclear medicine diagnosis technique in which an isotope tagged to a biochemical compound is injected into a patient’s vein. As the isotope decays, it emits photons from the body, and these photons are detected and recorded by a camera that provides a digital image of the distribution of the radiotracer in the body. Dynamic SPECT follows the dynamic process of the biochemical compound once it enters the blood, absorbed in organs and body tissues, and then either trapped within or released back into the blood stream or the lymph system. Dynamic SPECT imaging, acquired using detector heads that rotate while radiopharmaceuticals exchange between biological compartments, records the actual movement of the isotopes through the body.
Emission tomography is becoming increasingly important in modern medicine for both diagnostic and treatment monitoring with a demand for higher imaging quality, accuracy, and speed. Monte Carlo simulations have become an essential tool for current emission tomography development. GATE is a versatile and adaptable platform for simulating PET and SPECT experiments. GATE makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms.
Compartmental models are widely applied to solve a broad spectrum of physiologic and clinical problems related to the distribution of materials in living systems. A compartmental model is clearly unique for each system studied because it contains known and hypothesized physiology to that system.
In my degree work, the aim was to design and implement a realistic simulation of kidney dynamic SPECT imaging. We created three mathematical phantoms of the kidneys with varying degrees of detail for using in realistic dynamic SPECT imaging simulation and to test dynamic reconstruction algorithms. A pharmacokinetic phantom was created using compartment analysis to determine time-varying activity of normal functioning and dysfunctioning kidneys. Furthermore we built a software to create projection images from the output data of the simulation.