However, this progress was not easy since it called for specialized skills of physicists, engineers, and chemists, whose collective knowledge created a hybrid system in collaboration with medical expertise, primarily to complement medical management of diseases, and since then diagnostic medical imaging became a team activity (Beyer et al., 2000). In this assignment, the introduction of hybrid technologies such as PET and SPECT will be reviewed from current literature with the background physical principles applicable in these diagnostic imaging modalities, and it will be investigated how the basic principles of computerized tomography has advanced based on these platforms. Innovative technologies have their benefits, but implementing them in the clinical areas used to convention is always a challenge. This assignment will explore this trade-off based on current advances so an idea of future developments and implications of these technologies are evident to the reader.
Imaging applies the concept that human body serves as a complex object. Human body demonstrates the characteristics of any other physical object. These include transmissivity, opacity, emissivity, reflectivity, conductivity, and magnetizability. A specially designed imaging system that can capture the changes in these characteristics with disease would serve as an imaging device. The variations in these characteristics can be analyzed to yield information which can be clinically significant to lead to a pathologic diagnosis. In the X-ray that serves as the prototype of the initial investigative modality used basically cathode rays to create images of the human body parts on the fluorescent screens (Rappoport et al., 2004). This was effected by emission of x-rays from the cathode ray tube. X-ray can be attenuated by different materials of different densities and can be transmitted through and can be captured by a photographic plate. Later, it was established that X-ray is electromagnetic in nature. These comprise of photons with specific wavelengths, frequency, and energy. The electromagnetic spectrum of X-ray can be divided into several bands. Those with long wavelengths were used in magnetic resonance imaging. The next significant wave length is X-ray which is used in conventional radiography. Some ultra-short waves, which are high-energy gamma rays, are used in nuclear imaging (Valk et al., 2003).
Physical Principles of X-ray
If we consider the physical principles, X-rays are generated in an X-ray tube which comprises of a vacuum tube with a cathode and an anode in an environment of high potential difference. When electricity is passed, the cathode current releases electrons at the cathode through thermal excitation. The voltage difference between the cathode and the anode then drives these electrons in an accelerated fashion which then hit the anode plate to release the energy, which in part is X-ray. It is important to be aware that in order to produce an image from the attenuated X-ray beam, these beams need to be captured and converted to an image. Recent advents of technologies have enabled digital capture of images. Traditionally, however, screen-film detectors and the image