Computed Tomography | CT Scanners | Biomedical Engineers TV |

Summary

This video from Biomedical Engineers TV explores the history, principles, and components of CT scanners, also known as computed tomography machines. It highlights the invention of the CT scanner by Godfrey Hounsfield in 1971 and its contribution to medical imaging. The video explains the fundamental principles behind CT technology, including x-ray emission and image reconstruction, and delves into key components like the gantry, x-ray tube, slip rings, cooling systems, and detectors. The content provides a comprehensive look at how these components work together to produce detailed body images for diagnostic purposes.

Takeaways

• 🧑‍🔬 Godfrey Hounsfield invented the computed axial tomography (CT) scan, earning the Nobel Prize in 1979.
• 🏥 The first use of the CT machine was in 1971 at Atkinson-Morley's Hospital in Wimbledon, UK.
• 🧠 CT scans work by measuring the density of tissues using x-ray attenuation to create 3D images of the body.
• ⚛️ CT scanning involves two main absorption processes: the photoelectric effect and the Compton effect.
• 🌀 The CT machine has three major components: an x-ray tube, a gantry (housing detectors), and a computer for image processing.
• 🔄 Newer CT systems use slip rings for continuous rotation, allowing for helical scanning and improving image quality.
• 🧊 Cooling systems, like blowers or oil-to-air heat exchangers, are crucial in preventing overheating of the CT components.
• 🩻 X-ray tubes with tungsten targets in CT machines produce high-intensity x-ray beams, which are essential for sharper imaging.
• 🌡️ Filters in CT scanners reduce radiation dose and improve image quality by filtering out unnecessary soft x-rays.
• 📏 Collimators in the CT scanner focus the x-ray beam and control slice thickness, enhancing contrast resolution and reducing scatter radiation.

Q & A

Who invented the computed axial tomography (CT) scan, and when did this invention occur?

The computed axial tomography (CT) scan was invented by Godfrey Hounsfield, a biomedical engineer. He introduced the CT scan in 1971 and was awarded the Nobel Prize in 1979 for his contributions.

What role did James Ambrose and Lewis Creel play in the development of the CT scanner?

James Ambrose and Lewis Creel were radiologists who collaborated with Godfrey Hounsfield during the development of the CT scanner, helping to introduce its use at Atkinson-Morley’s Hospital in Wimbledon.

What is the fundamental principle behind the operation of a CT scanner?

CT scanners operate based on the principle that the density of tissue passed by the x-ray beam can be measured by calculating the attenuation coefficient. This principle allows the reconstruction of the body's density in two-dimensional sections.

What are the two main processes of x-ray absorption in a CT scanner?

The two main processes of x-ray absorption in a CT scanner are the photoelectric effect and the Compton effect.

How does a CT scanner differ from standard x-ray radiography in terms of image capture?

Unlike x-ray radiography, where images are produced directly, CT scanners use detectors to measure the transmission of thin x-ray beams and build 3D representations of the body by capturing images from different angles.

What are the main components of a CT scanner?

The main components of a CT scanner are the gantry (which includes the x-ray tube and detectors), slip rings, the generator, cooling systems, the x-ray tube, filtration, collimators, and detectors.

What is the purpose of the gantry in a CT scanner?

The gantry is the ring-shaped part of the CT scanner that houses essential components like the x-ray tube and detectors. It rotates around the patient during scanning and is responsible for aligning and positioning the patient for accurate imaging.

How do slip rings improve the functionality of CT scanners?

Slip rings allow the gantry frame to rotate continuously by using an electromechanical device, eliminating the need for recoiling cables. This enables helical scan modes and improves the efficiency of the scanner.

What role does collimation play in CT scanning?

Collimation restricts the x-ray beam to a specific area, reducing scatter radiation, which improves contrast resolution and reduces the patient's radiation dose. It also helps control the slice thickness by narrowing or widening the x-ray beam.

Why are compensating filters used in CT scanners?

Compensating filters are used to shape the x-ray beam, reducing radiation dose to the patient and minimizing image artifacts caused by beam hardening. Filtering helps create more uniform beam intensity and improves the overall image quality.