1. The three major systems in a Computed Tomography (CT) scan are the Imaging System, the Data Acquisition System (DAS), and the Computer System.
2. The purpose of the Imaging System in CT is to produce detailed cross-sectional images of the body using X-ray technology. These images help in diagnosing and monitoring various medical conditions.
3. The components of the Imaging System include:
- Gantry assembly: It houses the X-ray tube, detector, and other necessary components.
- X-ray Generator: Provides the necessary power to the X-ray tube.
- Collimators: Help in shaping the X-ray beam.
- Filtration system: Removes low-energy X-rays to enhance image quality.
- CT scan detector: Captures the X-rays after they pass through the body.
- Data acquisition electronics: Process the signals from the detector and convert them into digital data.
4. The Gantry assembly X-ray tube of a CT scanner consists of an X-ray source that produces the X-ray beam. It is usually a rotating anode X-ray tube capable of producing a high-intensity and focused X-ray beam.
5. The X-ray Generator in the Gantry assembly of a CT scan provides the necessary electrical power to the X-ray tube. It controls the X-ray tube current, voltage, and exposure time to produce the desired X-ray beam characteristics.
6. Collimators inside the Gantry of a CT scan help in shaping and limiting the X-ray beam. They are adjustable and can be used to control the width and thickness of the X-ray beam.
7. The different types of filtration inside the Gantry of a CT scanner include inherent filtration and added filtration. Inherent filtration refers to the filtration materials present in the X-ray tube and its housing, while added filtration includes additional materials placed in the X-ray beam path to remove low-energy X-rays.
8. The CT scan detector, which is also part of the Gantry in the CT scanner, captures the X-rays after they pass through the body. It is responsible for converting the X-rays into electrical signals that can be processed by the data acquisition system.
9. CT scan detectors used in CT scanners can be categorized into two types: scintillation detectors and solid-state detectors. Scintillation detectors use a scintillation crystal (such as sodium iodide or cesium iodide) to convert X-rays into light, which is then detected by photomultiplier tubes. Solid-state detectors use materials like selenium or silicon to directly convert X-rays into electrical signals.
10. Commonly used materials as CT scan detectors include:
- Scintillation crystals: Sodium iodide (NaI), cesium iodide (CsI), and gadolinium oxysulfide (GOS).
- Photomultiplier tubes: Used in conjunction with scintillation crystals to detect and amplify the light signals.
- Solid-state detectors: Materials like selenium, silicon, or cadmium telluride (CdTe) are used to directly convert X-rays into electrical signals. These detectors are often arranged in an array configuration for better spatial resolution.
