PET, CT and MRI are medical techniques based on phenomenons belonging to the quantum physics. This is why I chose to present them together in this very important chapter of understanding various imaging techniques used in medicine to diagnose diseases.
In the introductory part I described the phenomenons of quantum physics used in medicine. They are radioactivity and electromagnetic waves. I introduced and compared to each other all the types of radioactivity, alfa, beta, gamma, and all the types of electromagnetic waves belonging to the spectrum.
The section dedicated to scintigraphy, SPECT and PET scan opens up with the description of gamma rays and how they are used in the diagnosis of diseases. I presented the concept of radiotracer as well as Tc99m and FDG, the most used radiotracers for 2D, 3D scan and PET scan respectively. 2D (scintigraphy), 3D (SPECT) and PET scan are analyzed through comparison followed by a few images obtained through these techniques, together with my explanations related to their main use.
X ray section focuses on the production of this type of electromagnetic radiation in an X ray tube, their interaction with the matter and the final product, the X ray film. I introduced a short history about the beginning of the X rays and also the most recent history related to the development of the CT scan followed by the CT scan working principle.
In the MRI section I presented this technique based on NMR. I introduced then each element that makes this imaging possible. I refer here to the radio frequency waves, the strong magnetic fields and the behavior of atomic nuclei (protons) in interaction with them. Longitudinal magnetization, precession, Larmor frequency, resonance, transverse magnetization, T1 and T2 relation, proton density, pulse sequence, repetition time and echo time are important concepts that I introduced and explained. Various applications of MRI, the MRI scanner and a brief history of MRI and brain imaging ends up my presentation of this important part of imaging in medicine.