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Focal Spot
CT x-ray tubes have two focal spots, with filaments ranging from 0.5 mm to 1.2 mm in diameter.- Small focal spot: high resolution thin slices -Large: to cover large scan area have higher power ratings. (i.e abdominal scans)
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X-ray Tube
Similar to conventional x-ray tubes. Must be very durable due to the high centrifugal force as it whips around inside the gantry.
- Capable of achieving up to 800 mA.
-Generates a peak kilovoltage of 80-140 KVP. -
Beam Shaping Filter
Tube has filtration in the form of the tube housing, cooling oil, thin copper sheets, and a bow-tie filter.
- Bow-tie filters: most objects are cylindrical so less radiation is needed on the edges, therefore the beam is concentrating towards the center. -
Pre-Pt Collimation
A component of the CT scanner that it located between the x-ray source and the patient. This limits the area of the patient being scanned which allows you to set the slice thickness. -
X-Ray Beam
X-ray beam moves in a circle around the body. This allows many different views of the same organ or structure and provides much greater detail. -
Scan Field of View
The actual area of interest being selected by the Rad. Tech to be scanned which determines the number of detectors needed to collect the data.
-Must be larger than the area of interest due to any area outside SFOV will NOT be displayed. -
Paitent
A patient lies on a table that moves into the CT scanner. An X-ray source rotates around the patient, taking a series of images from different angles. -
Pre-detector collimation
This collimator is located between the paitent and the detector array. Acting as a filter that limits the x-ray beam reaching the detectors to only the desires slice thickness. Reducing scatter and improving image quality.
- Also known as the "Post-Patient Collimator" -
Detector
Responsible for capturing the transmitted radiation converting it into electrical signal to be used for image reconstruction.
-Composed of Gas Ionizing Chambers OR Solid State -
Electrical Signal/Project Profile
The specific parameters and settings used to acquire a CT image, including details like the SFOV, slice thickness, reconstruction algorithm, radiation dose, and the specific body part being imaged, essentially outlining the "blueprint" for capturing a particular CT scan for diagnostic purpose -
ADC
"ADC" stands for "Apparent Diffusion Coefficient," which is a quantitative measure of how freely water molecules can move within a tissue, often used to help differentiate between healthy and abnormal tissue by assessing the level of cellular density. -
Digital Data
The digital image is displayed on the matrix composed of pixels arranged in rows and columns. -
Computer Array Processor
A high-speed processor that accelerates the computation of images into raw data. -
DAC
Digital to analog converter helps convert the produced 1's and 0's into a visible image. -
Monitor
Where imaging is displayed for techs and Radiologist to view.