20.4 Computed Tomography Scanning (CT-Scan)
Computed Tomography, commonly known as CT-Scan, is a medical imaging technique that combines X-ray technology with computer processing to generate high-resolution cross-sectional and 3D images of internal body structures. It is especially useful for diagnosing diseases, detecting internal injuries, and guiding medical treatment. An ordinary X-ray shows a flat (2D) image of the body, where different parts like bones and organs overlap each other. This makes it hard to see individual structures clearly. For example, in Fig. 20.7, it's difficult to tell the front and back ribs apart because they appear on top of each other. To solve this problem, doctors use a special technique called CT scan (Computed Tomography).
(Fig. 20.7)
A CT scanner takes many X-ray images of the same body section from different angles. A computer combines these images to make a detailed cross-sectional (slice) image of the body. Then, the scanner moves slightly along the body and repeats the process for the next slice. In the end, all these slices are combined by the computer to create a 3D image of the internal structure.
(Fig. 20.8: Operation of CT-scanner)
In a CT machine, the X-ray tube rotates around the patient while detectors stay in place. This setup collects complete information from all sides, as shown in Fig. 20.8. The name computed tomography comes from:
- Computed: A computer processes the data.
- Tomography: From the Greek word tomos, meaning slice.
- Axial: The scan is taken along the body's axis (line through the body).
(Fig. 20.9: A boy undergoing a CT scan; monitor shows head cross-section.)
Do you know?
lightbulbThe CT-scanner was invented by Sir Godfrey Hounsfield (England) and Allan Cormack (South Africa) in the early 1970s. For this invention, both scientists were awarded the Nobel Prize in Physiology or Medicine in 1979.
Do you know?
lightbulbCT-scans create hundreds of slices are images in seconds like peeling a digital apple layer by layer. CT-scans can detect strokes within minutes of onset crucial for lifesaving treatment.
This way, doctors can get a clear and detailed view of internal organs, bones, or tissues. Fig. 20.9 shows a child having a CT scan, and the monitor displays a cross-sectional image of the head. This technique is called Computed Axial Tomography (CT scan) because it uses a computer to control the scanning process, collect data, and convert it into images. The X-ray tube rotates around the patient's body, capturing images from different angles. These images are then used to create detailed cross-sectional slices of the body. The word "tomography" comes from the Greek word tomos, meaning "slice," which refers to how the body is imaged layer by layer.