Foundations of Medical Imaging and Signal Recording - Biomedical Signal Analysis: Contemporary Methods and Applications - page 11

2D Fourier Transform

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1D Fourier Transform

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Figure 1.5
Visualization of the projection-slice theorem.

more information than X-rays or ultrasound. It is employed mostly in
the diagnosis of cerebrovascular diseases, acute and chronic changes
of the lung parenchyma, supporting ECG, and a detailed diagnosis of
abdominal and pelvic organs. A CT image is shown in figure 1.6.
Nuclear medicine began in the late 1930s, and many of its procedures
use radiopharmaceuticals. Its beginning marked the use of radioactive
iodine to treat thyroid disease. Like x-ray imaging, nuclear medicine
imaging developed from projection imaging to tomographic imaging.
Nuclear medicine is based on ionizing radiation, and image generation is
similar to an x-ray's, but with an emphasis on the physiological function
rather than anatomy. However, in nuclear medicine , radiotracers, and
thus the source of emission, are introduced into the body. This technique
is a functional imaging modality: the physiology and biochemistry of the
body determine the spatial distribution of measurable radiation of the
radiotracer. In nuclear medicine, different radiotracers visualize different
functions and thus provide different information. In other words, a
variety of physiological and biochemical functions can be visualized by
different radiotracers. The emissions from a patient are recorded by