Radiographic Grid.pptx

Radiographic Grid.pptx

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  Radiographic Grid Presenter: Dr.Dheeraj Kumar MRIT, Ph.D. (Radiology and Imaging) Assistant Professor Medical Radiology and Imaging Technology School of Health Sciences, CSJM University, Kanpur 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 1
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  Introduction • Radiographic gridsare devices designed to minimize scatter radiation while preserving the primary X-rays that contribute to image formation. • They consist of alternating radiopaque lead strips and interspace material, creating a matrix that selectively allows primary radiation to pass through while absorbing scattered radiation. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 2
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  Working Principle • Theworking principle of radiographic grids lies in their ability to absorb scattered radiation. • When X-rays pass through the patient, some are scattered in various directions. • The lead strips in the grid absorb a significant portion of this scattered radiation. As a result, the primary X-rays, necessary for image formation, remain predominant. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 3
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  History • The mid-20thcentury marked a turning point with the introduction of the first radiographic grids. • Pioneers like Hollis Potter and Gustave Bucky recognized the need to tackle the issue of scatter and explored innovative solutions. • In 1904, Bucky's invention of the grid, known as the "Bucky Grid," was a pivotal step toward achieving clearer images. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 4
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  Types of Grids •Parallel Grids: These have lead strips running parallel to each other and are well-suited for examinations with minimal divergence of X- ray beams. • Focused Grids: In these grids, lead strips are angled to match the divergence of X-rays, reducing the risk of grid cut-off and allowing for greater latitude in patient positioning. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 5
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  Moving grids • Movinggrids are innovative devices designed to counteract the challenges associated with stationary grids. • They incorporate a mechanism that introduces controlled motion to the grid during the X-ray exposure. • This motion helps minimize the impact of grid lines, grid cut-off, and the Moiré effect on the final radiographic image. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 6
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  Scatter Radiation andIts Effects • Scatter Radiation Defined: Scatter radiation refers to secondary X-rays that result from the interaction of primary X-rays with patient tissues. It contributes to decreased image quality. • Impact on Image Quality: Scatter radiation reduces image contrast, blurs fine details, and affects overall diagnostic accuracy, making its control vital. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 7
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  Components of RadiographicGrids • Radiopaque Strips: Radiopaque lead strips within the grid absorb scattered radiation, preventing it from reaching the image receptor. • Interspace Material: Interspace material, often made of aluminum or plastic, allows primary X- rays to pass through, contributing to the formation of the radiographic image. • Grid Ratio: Grid ratio is the ratio of the height of the lead strip to the width of the interspace material. It determines scatter absorption efficiency and image quality. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 8
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  Grid Ratio andImage Quality • Grid Ratio Explained: Grid ratio directly impacts image quality. A higher grid ratio increases scatter absorption, enhancing image contrast but also requiring higher exposure factors. • Choosing the Right Ratio: Selecting the appropriate grid ratio depends on the imaging scenario. Higher ratios are favoured for specialized imaging while lower ratios balance dose and image quality. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 9
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  Grid Frequency andDetail • Understanding Grid Frequency: Grid frequency refers to the number of lead strips per unit length (usually per inch or centimeter). Higher grid frequency reduces visibility of grid lines on the image. • Influence on Image Detail: Higher grid frequency results in improved image detail and clarity, making it ideal for capturing fine anatomical structures. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 10
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  Grid Alignment andFocusing Distance • Importance of Proper Alignment: Accurate alignment of the grid and central X-ray beam is essential to prevent grid cut-off and ensure consistent image quality across the entire field. • Impact of Focusing Distance: Maintaining the recommended focusing distance between the grid and the patient helps optimize image quality by minimizing distortion and artifacts. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 11
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  Grid Cut-off andErrors • Grid Cut-off Explained: Grid cut-off occurs when improper positioning or incorrect technique factors lead to a reduction in primary radiation reaching the image receptor. • Common Errors: Off-center grids result from misalignment of the X- ray tube and grid, while upside-down grids lead to grid cutoff due to reversed lead strip orientation. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 12
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  Advancements in GridTechnology • Moving Grids: Moving grids introduce dynamic motion during exposure to minimize the appearance of grid lines on the image, enhancing image quality. • Stationary Grids with Software Correction: Stationary grids, coupled with software-based corrections, compensate for grid-related artifacts, resulting in cleaner images. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 13
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  Digital Radiography andGrids • Grid Considerations in Digital Imaging: Digital imaging systems require adjustments due to increased grid absorption, necessitating modifications in technique factors. • Importance of Grids in Digital Imaging: Despite advancements in digital technology, grids remain essential for improving image quality and diagnostic accuracy. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 14
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  Practical Application andCare • Proper Positioning: Accurate grid positioning ensures that the central X-ray beam is aligned, minimizing artifacts and maintaining image quality. • Collimation and Field Coverage: Proper collimation not only reduces patient exposure to radiation but also ensures the image is well- centered and high in quality. 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 15
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  References • Bushong, S.C. (2018). Radiologic Science for Technologists: Physics, Biology, and Protection. Mosby. • Fauber, T. L. (2019). Radiographic Imaging and Exposure. Elsevier Health Sciences. • Carlton, R. R., & Adler, A. M. (2016). Principles of Radiographic Imaging: An Art and A Science. Cengage Learning. • Clark, K. R., Bushong, S. C., & Slovis, T. L. (2019). Essentials of Radiographic Physics and Imaging. Elsevier Health Sciences. • 04/09/2023 Radiographic Grid By- Dr. Dheeraj Kumar 16
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  04/09/2023 Radiographic GridBy- Dr. Dheeraj Kumar 17