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INNOSC Theranostics and
Pharmacological Sciences Medical imaging technology

This integration offers comprehensive insights into disease The emergence of XCT introduced a new concept in
processes and treatment responses. These advancements medical imaging. XCT uses extensive X-ray absorption
in imaging methodologies hold immense potential for data obtained from scanning around the body’s organs to
optimizing patient care, guiding therapeutic interventions, reconstruct tomographic images. When a beam of thin
and advancing our understanding of complex diseases. (fan-shaped) X-rays passes through a section of the body’s
However, challenges concerning cost, accessibility, and organs, the total attenuation coefficient along the X-ray
standardization must be addressed to fully realize the path is the line integral of the voxel attenuation coefficients,
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clinical benefits of these innovative technologies. Future which can be measured with a detector. Detectors convert
research efforts should focus on refining imaging protocols, the intensity of the rays into electrical signals, which are
validating diagnostic accuracy, and expanding the clinical digitized and processed by computers. By conducting
utility of these cutting-edge imaging modalities across multiple measurements at different angles around the
diverse medical specialties. organs, the absorption coefficient related to each voxel at a
specific level is calculated. The resulting two-dimensional
3.1. X-ray imaging absorption coefficient matrix is stored in the computer,
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Roentgen discovered X-rays in 1895, which was the greatest using different gray scales. This matrix information is then
discovery in medical diagnostics in the 19 century. X-ray displayed as an image. The grayscale of each pixel on the
th
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fluoroscopy and photography technology, as the earliest displayed image corresponds to the absorption coefficient
forms of medical imaging technology, remain among the of the respective voxel, thereby providing information on
most commonly used medical diagnostic methods today, the distribution of the attenuation coefficient on the fault
holding considerable clinical value. The signal detected by plane. XCT technology is called tomography because it
the X-ray imaging system is the intensity of X-rays after obtains a cross-sectional image of the body’s organs.
they penetrate the tissue, reflecting differences in the This digital imaging technology has evolved from the
X-ray absorption coefficients of various human tissues. first generation to the fifth generation. At present, the third
This difference is due to variations in tissue thickness and and fourth generations are commonly used. The continued
density, which the image captures, showing the shape of development of these two generations of CT technology
tissues, organs, and diseased areas. For more than half a has primarily focused on improving speed, enhancing
century, medical imaging science progressed steadily but image quality, developing new functions, expanding the
slowly alongside advancements in X-ray technology. In scope of applications, and facilitating operations. For
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the early 1970s, the introduction of computerized X-ray example, spiral scanning can reduce the time needed to
tomography (XCT) marked a period of rapid development scan the same coverage length by one-quarter to one-fifth
in medical imaging. CT involves taking thousands of or increase the scanning coverage length by 25 – 33%
X-rays from different angles. The substantial amount of in the same amount of time. Another manifestation of
data collected is processed by computers to form a three- increased speed is the shortened image reconstruction
dimensional image of any part of the body. Doctors can time. Some CT products adopt new image reconstruction
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instruct the computer to display a two-dimensional cross- technology, increasing the reconstruction time to one
section at any depth from any direction. CT scanning second, thus speeding up the scanning cycle. High-end
has brought revolutionary changes to medical diagnosis, CTs with continuous imaging or fluoroscopy functions can
allowing doctors to detect brain bleeding in head injuries or display six to eight images per second. CT fluoroscopy is
visualize the shape and extent of tumors in cancer patients. 4 very important for interventional radiology, as it reduces
CT uses a digital signal input to the computer for the number of scanning layers and the patient’s X-ray
processing. The processing of image formation involves exposure dose. Some products can achieve a 512 × 512
dividing the selected layer into several cuboids of equal matrix image with a scanning dose of only 15 mA. Further
volume, called voxels. The information obtained through studies are ongoing on CT fluoroscopy technology using
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scanning is used to calculate the X-ray attenuation an X-ray exposure dose of 10 mA. In terms of image
coefficient or absorption coefficient of each voxel, which quality, the spatial resolution of high-end, low-voltage
is then arranged into a digital matrix. Digital matrices can spiral CT machines has reached 20 lp/cm, with high low-
be stored on magnetic or optical disks. A digital-to-analog contrast resolution, significantly improving the ability to
converter transforms each number in the digital matrix differentiate soft tissues.
into small squares of grayscale, ranging from black to The new generation of CT is called electron beam
white, called pixels. These pixels are arranged in a matrix CT (EBCT). In EBCT, an electron beam is emitted by an
to form a CT image. electron gun, and a deflection coil changes the direction

Volume 7 Issue 3 (2024) 3 doi: 10.36922/itps.3360