Basic Principles and History of CT Scan.pptx

Computed Tomography (CT) is a medical imaging technique that uses X-ray technology to produce detailed cross-sectional images of the body.
It is a valuable tool for diagnosing and monitoring a wide range of medical conditions

1. Basic Principles and History of CT Scan Presenter: Dr. Dheeraj Kumar MRIT, Ph.D. (Radiology and Imaging) Assistant Professor Medical Radiology and Imaging Technology School of Health Sciences, CSJM University, Kanpur

2. Introduction Definition of CT Scan (Computed Tomography) Computed Tomography (CT) is a medical imaging technique that uses X-ray technology to produce detailed cross-sectional images of the body. It is a valuable tool for diagnosing and monitoring a wide range of medical conditions. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 2

3. Importance in Modern Medical Imaging CT scans provide high-resolution images that help physicians visualize internal structures and detect abnormalities. They play a crucial role in guiding medical decisions and treatment planning. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 3

4. Role in Diagnosing and Monitoring Diseases CT scans are used to identify and evaluate various medical conditions, such as fractures, tumors, vascular diseases, and infections. They are also used to monitor treatment progress and guide interventions. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 4

5. Historical Background Invention and Development of CT Scan The CT scan was invented in the early 1970s by British engineer Sir Godfrey Hounsfield and South African physicist Allan Cormack. Their ground-breaking work led to the development of the first CT scanner, which produced cross-sectional images of the body. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 5

6. Sir Godfrey Hounsfield and Allan Cormack In recognition of their contributions, Hounsfield and Cormack were awarded the Nobel Prize in Physiology or Medicine in 1979. Their work laid the foundation for modern medical imaging techniques. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 6

7. Early CT Scanners and Their Limitations Early CT scanners had limited image quality and required a long scan time. The technology has since evolved significantly, resulting in faster scans and improved image resolution. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 7

8. Principles of CT Imaging X-ray Technology Foundation CT scans are based on X-ray technology, which involves passing X-rays through the body and measuring their attenuation by different tissues. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 8

9. Cross-sectional Imaging CT imaging provides detailed cross-sectional slices of the body, allowing visualization of internal structures from multiple angles. This capability helps in detecting abnormalities that may not be apparent on traditional X-rays. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 9

10. Mathematical Reconstruction Algorithms CT images are reconstructed from a series of X-ray measurements using mathematical algorithms. These algorithms help convert raw data into detailed images that reflect tissue density variations. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 10

11. Attenuation and Hounsfield Units (HU) Attenuation refers to the reduction in X-ray intensity as it passes through tissues. Hounsfield Units (HU) quantify tissue attenuation and are used to classify tissues based on their density. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 11

12. X-ray Technology and Attenuation X-rays are a type of electromagnetic radiation with higher energy than visible light. They can penetrate the body and are absorbed to varying degrees by different tissues. Different tissues attenuate X-rays to varying extents due to differences in density and atomic composition. This attenuation creates the contrast necessary for imaging. Variations in tissue attenuation create image contrast, enabling differentiation between different types of tissues. High contrast resolution is crucial for detecting subtle abnormalities. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 12

13. Cross-sectional Imaging Generation of Axial Slices : CT scanners acquire data in the form of axial slices, which are cross-sectional images of the body. These slices are reconstructed into a three-dimensional representation. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 13

14. Multi-planar Reformatting ( MPR) MPR allows radiologists to view the axial slices in different orientations (e.g., sagittal, coronal) to better understand anatomical relationships. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 14

15. Three-dimensional Reconstruction (3D ) By combining axial slices, software can create three-dimensional images that enhance visualization for surgical planning and research. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 15

16. Mathematical Reconstruction Algorithms Basics of Image Reconstruction Image reconstruction involves converting raw X-ray data into a visual representation of the body's internal structures. This process requires advanced mathematical algorithms. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 16

17. Filtered Back Projection (FBP) FBP is a classic reconstruction method that involves applying a filter to the raw data before back projecting it to create an image. It's efficient but may lead to image Artifacts. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 17

18. Iterative Reconstruction (IR) IR algorithms iteratively refine the reconstructed image by minimizing the difference between the acquired data and the estimated data. IR offers improved image quality and reduced noise but requires more computational resources. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 18

19. Hounsfield Units (HU) Quantification of Tissue Attenuation Hounsfield Units (HU) measure the attenuation of X-rays by different tissues and assign a numerical value to tissue density. The scale ranges from air (-1000 HU) to dense bone (+1000 HU). 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 19

20. Scale and Tissue Differentiation Hounsfield Units allow radiologists to differentiate between various tissues, such as fat, muscle, bone, and fluid. This differentiation aids in identifying abnormalities and characterizing structures. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 20

21. Clinical Applications of HU HU values are used in diagnosing diseases and evaluating treatment responses. They are essential for identifying lesions, quantifying calcifications, and assessing tissue composition. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 21

22. Components of a CT Scanner X-ray Tube and Detector Array The X-ray tube emits the X-ray beam, which passes through the body. The detector array captures the attenuated X-rays, creating the raw data for image reconstruction. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 22

23. Gantry Rotation and Patient Table The gantry is the circular part of the CT scanner that houses the X-ray tube and detector array. The gantry rotates around the patient during scanning, capturing data from different angles. The patient table moves through the gantry during scanning to ensure complete coverage of the body. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 23

24. Data Acquisition System The data acquisition system collects X-ray measurements from the detector array. These measurements are used for image reconstruction . 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 24

25. Types of CT Scanners Single-slice CT vs. Multi-slice CT Single-slice CT scanners acquire one slice per rotation, leading to longer scan times. Multi-slice CT scanners acquire multiple slices simultaneously, allowing faster scans and better image quality. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 25

26. Advantages of Multi-slice Scanners Faster imaging reduces patient discomfort and motion Artifacts. Higher spatial resolution and improved contrast resolution . Improved spatial resolution. Patient breath hold is much less demanding. Less contrast media required. Improved accuracy in needle placement CT Fluoroscopy. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 26

27. Dynamic and Dual-energy CT Dynamic CT captures images in real-time, suitable for vascular and perfusion studies. Dual-energy CT uses two different energy levels, enhancing tissue differentiation and material characterization. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 27

28. Safety Considerations Ionizing Radiation Exposure CT scans involve ionizing radiation, which can pose a risk of cumulative radiation exposure. Radiologists use techniques to minimize radiation dose while maintaining image quality. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 28

29. Dose Reduction Techniques Tube current modulation and automatic exposure control adjust radiation output based on patient size and anatomy. Iterative reconstruction algorithms reduce noise, allowing lower radiation doses. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 29

30. Benefits vs. Risks The benefits of accurate diagnosis often outweigh the risks of radiation exposure, especially in cases where alternative methods are less informative. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 30

31. Recent Advances Dual-Source CT and Rapid Scanning Dual-source CT uses two X-ray sources and detectors for even faster imaging. Rapid scanning reduces motion Artifacts and enables better visualization of moving structures. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 31

32. Spectral CT and Material Differentiation Spectral CT captures multiple energy levels, allowing material characterization. It helps distinguish different types of materials, such as calcium, iodine, and water. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 32

33. Artificial Intelligence in CT Interpretation AI algorithms assist radiologists in image analysis, automated segmentation, and lesion detection. They improve efficiency and accuracy in diagnosing complex cases. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 33

34. Conclusion In conclusion, the journey from the inception of the CT scan to its current state of technological sophistication has been remarkable. Computed Tomography has become an invaluable asset in the world of medical imaging, transforming the way we diagnose and treat diseases. Its ability to produce high-resolution cross-sectional images, coupled with its continuous evolution, has revolutionized radiology and medicine as a whole. The CT scan's historical significance, fundamental principles, As we move forward, the integration of AI, ongoing advancements, and the synergy with other imaging modalities promise an exciting future for CT imaging, enabling even more personalized and accurate medical interventions. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 34

35. References Hounsfield GN, Cormack AM. Computed transaxial tomography (CT-scan): An approach to an automated X-ray diagnostic procedure. Br J Radiol . 1973;46(552):1016-1022. Webb WR, Brant WE, Major NM. Fundamentals of Body CT. Elsevier Health Sciences; 2011. Kalra MK, Maher MM, Toth TL, et al. Strategies for CT radiation dose optimization. Radiology. 2004;230(3):619-628. Mayo-Smith WW, Hara AK, Mahesh M, et al. How I do it: managing radiation dose in CT. Radiology. 2014;273(3):657-672. Kambadakone A, Sahani DV. Body perfusion CT: technique, clinical applications, and advances. Radiol Clin North Am. 2009;47(1):161-178. Kulkarni NM, Sahani DV. Imaging of gastrointestinal tract perforation. Radiol Clin North Am. 2015;53(1):77-88. 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 35

36. Thank You 09-08-2023 Basic Principles and History of CT Scan By- Dr. Dheeraj Kumar 36