Isotopic element has a specific decay pattern
Since each isotopic element has a specific decay pattern, if all available isotopes were examined, the resultant image would be hopelessly complicated, and the computer would not be able to resolve the image. In order to eliminate this variable, the use of magnetic resonance imagery focus on one isotope. In most cases, the isotope chosen is that of the hydrogen ion or 1H. This is because the hydrogen ion is one of the most plentiful in the human body, and the fluctuations in magnetization experienced by the proton in the hydrogen ion are one of the easiest to measure. However, other isotopes for other elements have been used as well, including 13C, 23Na, and 19F (Gomillion, et al, 2007).
By measuring the difference, and directionality of the excited magnetized hydrogen atoms in relation to the relaxed states, and their approximate locations in respect to the two magnetic fields (the static and introduced), the computer can then generate a cross-sectional image of the material based on the relative differences in density presented. These cross-sectional images are then compiled through a layering process to create a three-dimensional image of the patient being examined (Gomillion, et Al, 2007). Since normal tissue, bone, and pathological tissue often have different densities, a trained medical professional can utilize this machine and technique to aid in the localization of such things as tumors, foreign bodies, and abnormal growth patterns.
