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Table of Content
- History of the Computed Tomography
- How Does a Computed Tomography System Work?
- Which Materials are suitable for Scanning?
- Application of Industrial CT Scans
- Key Takeaways
- FAQs
Computed Tomography (CT) has irrevocably altered the landscape of NDT. By harnessing X-ray technology and sophisticated algorithms, CT enables the visualisation of internal structures with unprecedented clarity and detail. Whether it's scrutinising the integrity of aerospace components or assessing the quality of automotive parts, NDT CT stands for precision and reliability.
History of the Computed Tomography
The inception of computed tomography marks a pivotal moment in the history of medical imaging and non-destructive testing. It all began in the early 1970s, when two pioneers, Sir Godfrey Hounsfield, and Dr. Allan Cormack, independently laid down the mathematical foundations that would revolutionise diagnostic imaging.
1. Sir Godfrey Hounsfield's Contribution
Sir Godfrey Hounsfield, an English engineer, conceptualized the idea of reconstructing images from multiple X-ray projections. His breakthrough came in 1967 when he developed the mathematical algorithm known as the Radon transform, which made it possible to generate cross-sectional images of the human body.
2. Dr. Allan Cormack's Innovation
Around the same time, Dr. Allan Cormack, a South African physicist, was working on similar concepts. He formulated a mathematical technique known as the back-projection method, which complemented Hounsfield's work. Together, their efforts laid the groundwork for the development of the first CT scanner.
First CT Scanner
In 1972, the world witnessed the birth of the first computed tomography imaging scanner, known as the EMI Mark I. By providing precise cross-sectional images of the human body, Hounsfield and his team at EMI Laboratories in England revolutionised medical diagnostics.
Know More, How This Record Company Engineer Invented the CT Scanner
How Does a Computed Tomography System Work?
At the core of every Computed Tomography technologist lies a sophisticated mechanism that harnesses the power of X-rays to create detailed cross-sectional images of objects. Understanding how these systems function is essential for appreciating their role in both medical diagnostics and NDT. Here are the major components of computed tomography.
1. Rotating Gantry
The CT system features a rotating gantry, a circular structure that houses the X-ray source and detector array. This gantry rotates around the object being scanned, allowing for X-ray projections to be captured from multiple angles.
2. X-ray Source
The X-ray source emits a series of narrow beams of X-rays towards the object under examination. These X-rays penetrate through the object, interacting with its internal structures along the way.
3. Detector Array
Opposite the X-ray source, the detector array captures the attenuated X-rays that have passed through the object. Each detector element measures the intensity of the X-rays that reach it, creating a digital signal proportional to the X-ray absorption.
4. Scanning Process
The scanning process involves various steps that are performed by computed tomography technician. Here are the various steps and processes in detail.
5. Emitting X-ray Beams
During a CT scan, the X-ray source emits a series of beams that traverse the object from different angles. As the beams penetrate through the object, they undergo attenuation, with denser materials absorbing more X-rays than less dense ones.
6. Capturing Attenuated X-rays
The detector array, positioned opposite the X-ray source, captures the attenuated X-rays after they pass through the object. Each detector element records the intensity of the X-rays it receives, generating a digital signal.
7. Data Reconstruction
Once the data is collected from multiple projections, sophisticated algorithms come into play to reconstruct the raw data into cross-sectional images, also known as slices. These images provide detailed insights into the internal structures of the object being scanned.
Which Materials are Suitable for Scanning?
Computed tomography scanning is a versatile, non-destructive evaluation technique that offers unparalleled insights into the internal structures of various materials. While NDT CT services are suitable for a wide range of materials, including metals, plastics, ceramics, and composites, certain factors influence their effectiveness. These are the major material constraints to identify materials suitable for scanning.
X-ray Attenuation
One of the key factors determining the suitability of a material is computed tomography radiation with X-ray attenuation properties. Materials with higher X-ray attenuation, such as metals and ceramics, are more easily visualised during a NDT CT scan due to their ability to absorb and scatter X-rays effectively.
Density
The density of a material also plays a crucial role in its suitability for CT scanning and NDT imaging. Dense materials, such as metals and alloys, offer greater contrast in CT images compared to low-density materials like plastics and foams.
Internal Structure
The internal structure of a material can impact the quality of CT scans. Materials with intricate internal features, such as complex geometries or porous structures, may present challenges during image reconstruction, affecting the clarity and accuracy of the results.
Application of Industrial CT Scans
Industrial applications of computed tomography scans have emerged as indispensable tools across various industries, offering unparalleled capabilities in quality control, defect detection, and metrology. Here is the list of diverse applications of CT scanning in different sectors.
1. Automotive Industry
In the automotive industry, CT scanning plays a critical role in inspecting complex components such as engine blocks, cylinder heads, and turbine blades. CT technology enables manufacturers to detect defects like porosity, cracks, and voids with exceptional accuracy, ensuring the integrity and reliability of automotive parts.
2. Aerospace Industry
