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. ماما:
3.1.4 Data Acquisition and Reconstruction:
As the X-ray tube rotates around the patient, multiple projections of the

attenuated X-ray beam are acquired at different angles. These raw data are

then processed by a computer to reconstruct cross-sectional images of the

body using mathematical algorithms such as filtered back projection or

iterative reconstruction. By combining information from multiple

projections, CT scanners can produce high-resolution images with

excellent anatomical detail(16)
.
3.1.5 Image Display and Interpretation:
The reconstructed CT images are displayed on a computer monitor, where

they can be viewed and interpreted by radiologists or other healthcare

professionals. These images typically consist of grayscale representations

of tissue density, with brighter regions corresponding to areas of higher X-
ray attenuation. Radiologists analyze these images to identify

abnormalities, assess disease severity, and guide patient management

decisions(17)
.12

3.1.6 Radiation Dose Considerations:
One important aspect of CT imaging is the consideration of radiation dose.

CT scans involve exposure to ionizing radiation, which carries inherent

risks, particularly with repeated or high-dose exposures. Various

techniques, such as tube current modulation, dose modulation algorithms,

and iterative reconstruction, are employed to optimize image quality while

minimizing radiation dose to the patient(18)
.
3.2 The Principal Physics of DSCT:
3.2.1 Dual-Source CT Configuration:
Dual-source computed tomography (DSCT) employs two X-ray tubes and

detector arrays positioned at right

angles to each other within the

gantry. This unique configuration

allows for simultaneous acquisition

of data at two different energy levels.

The X-ray tubes are typically

operated at different kilovoltage

(kV) settings, such as 80 kV and 140

kV, to generate X-ray beams with

distinct spectral properties(19)
.
3.2.2 Spectral Separation:
The two X-ray tubes in DSCT emit X-ray photons with different energy

spectra. These energy spectra are characterized by variations in the number

and energy distribution of the emitted photons. By simultaneously

acquiring data at two different energy levels, DSCT enables spectral

3.2.3 Material Decomposition:
DSCT allows for energy-selective imaging, wherein specific energy ranges

are chosen to optimize image contrast for different diagnostic tasks. By

selecting appropriate energy levels, radiologists can enhance the

visualization of certain tissues or pathologies while minimizing the

appearance of artifacts or beam hardening effects(21)
.
3.2.4 Energy-Selective Imaging:
DSCT allows for energy-selective imaging, wherein specific energy ranges

are chosen to optimize image contrast for different diagnostic tasks. By

selecting appropriate energy levels, radiologists can enhance the

visualization of certain tissues or pathologies while minimizing the

appearance of artifacts or beam hardening effects(22)
.
3.2.5 Improved Temporal Resolution:
The dual-source configuration of DSCT also offers improved temporal

resolution compared to single-source CT scanners. This enhanced temporal

resolution is particularly advantageous for imaging moving structures,

such as the heart or coronary arteries, allowing for more accurate

assessment of cardiac function and dynamic processes(23)
.