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Computed tomography, commonly known as CT or CAT scanning, has revolutionized medical diagnosis by providing doctors detailed images of the inside of the body. This technology uses computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual “slices”) of specific areas of a person’s body.
The History of CT Scanning
The development of CT scanning began in the early 1970s and the first commercial CT scanner was introduced in 1973 by EMI. Since then, the technology has evolved rapidly. The revolutionary technology was developed by Sir Godfrey Hounsfield at EMI Laboratories. In 1979, Hounsfield shared the Nobel Prize in Physiology or Medicine with Allan M. Cormack for their groundbreaking work in developing CT scan technology.
The early CT scanners took about 5 minutes to produce just a single slice and the images were often difficult to interpret. Today, modern multi-slice CT scanners can image the entire volume of the body within seconds and produce detailed pictures of unprecedented quality. Advances in computing power, detector technology and scanning methods have made CT scans much faster, more detailed and more widely available.
How CT Scanning Works
A CT scan uses a combination of X-rays and computer technology to produce cross-sectional images of the body. During a routine CT scan, the person lies on a table that slides into a large circular opening of the scanning machine. The machine takes a series of X-ray pictures from various angles around the body and uses computer processing of the X-ray measurements to construct cross-sectional images of the body tissues and organs.
The X-ray source projects a narrow beam of X-rays through the body from many angles, while X-ray detectors measure the absorption and transmission of the beams. A computer processes this large volume of data using an inverse Radon transform to produce a sequence of digital images, or slices, of your anatomy. Multiple slices are taken as the table slowly slides through the scanner.
Advantages of CT Scanning
CT scanners offer several advantages over conventional X-rays:
– Detail and Contrast: CT images provide far more anatomical details than regular X-rays. The use of computer processing to generate detailed images allows physicians to clearly distinguish between different types of body tissues — the densities of which determine their brightness on CT images.
– Slice Imaging: CT images sliced along the long axis of the body allows physicians to examine the internal organs slice by slice, like leaves in a book. This provides a 3D view of structures inside the body.
– Fast Scanning: Modern multi-slice CT scanners can image the entire volume of the body within seconds. This ensures minimum motion artifacts from things like breathing and heartbeat.
– Versatility: CT scans can highlight problems within bones, soft tissue and blood vessels. A wide range of pathologies can be detected that may not be discovered using other imaging techniques.
Applications of CT Scanning
Some common clinical applications of CT scanning include:
– Brain and Neuroimaging: Head CT scans are frequently used to detect cerebral haemorrhages, tumors, strokes, blood clots and other brain disorders.
– Chest Imaging: CT scanning is highly useful for lung diseases like cancer, emphysema, pneumonia and blood clots in the lungs. It is also done for mediastinal Evaluation.
– Abdomen and Pelvis: Diseases of the abdomen like appendicitis, hernias, masses, infections and cancers can be diagnosed. CT urography visualizes kidneys, ureters and bladder.
– Angiography: CT angiography uses contrast material injected intravenously to visualize arteries and detect aneurysms, narrowings, blood clots or other conditions.
– Bone Imaging: CT is highly effective for evaluation of fractures, tumors, infections, abnormalities and trauma involving bones. It clearly shows cortical and medullary anatomy.
– Cancer Screening and Staging: Whole body low dose CT scans can detect small lung cancers. CT also stages cancers by depicting the extent and size of primary tumors and lymph node involvement.
– Image-Guided Procedures: CT provides real-time image guidance for minimally invasive procedures like biopsy, drainage, abscess incision and fine needle aspiration.
Risks and Precautions of CT Scanning
While CT scanning is highly beneficial for medical diagnosis, there are some risks associated with exposure to ionizing radiation. The X-ray radiation used in CT scans can potentially increase lifetime cancer risk. Repeated CT scans or those done on children and younger individuals pose a higher risk as their tissues are more radiation sensitive.
Physicians carefully weigh the risks versus benefits of CT imaging based on individual clinical circumstances. Dose reduction techniques have significantly lowered radiation exposure levels from CT scans. Appropriate use guidelines reduce unnecessary scans. Overall, the medical benefits of CT far outweigh radiation risks when standard precautions are followed. With its remarkable diagnostic power, CT scanning has revolutionized modern patient care by giving physicians a virtual window inside the human body.
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- Source: Coherent Market Insights, Public sources, Desk research
- We have leveraged AI tools to mine information and compile it
