Scanning systems, CT Scan

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Scanning systems, CT Scan

  1. 1. Scanning Systems, CT • GROUP MEMBER: AHMAD RAFIQAN BIN NAYAN Muhammad Irfan Bin Alias Mohammad Al-Karim Tayasneh Mohd Izzad Samir Bin Iskandar 1. AXIAL CAT SCANNER 2. COMPUTED TOMOGRAPHY SYSTEM 3. HELICAL CT SCANNER 4. MULTISLICE CT SCANNER 5. SPIRAL CT SCANNER 6. ULTRAFAST CT SCANNER 7. VOLUME CT SCANNER 8. COMPUTED RADIOGARPHY CT SANNER
  2. 2. INTRODUCTION • A computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. • What is the different spectrometry CT and scanning system CT?
  3. 3. Block diagram of CT Scan X-tray tube Detector scanner Detector High voltage supply Gantry Camera O/P unit
  4. 4. Detector Two type of detector : 1. Scintillation crystal 2. Ionization chamber Scintillation crystal Combination of Bismuth germanate crystals with photomultiplier or sodium iodide crystals which is less afterglow and more efficient Ionization chamber Contain xenon gas under pressure which have no afterglow and less efficient. Have two conductor forming capacitor where high voltage is applied to it. The chamber ionizes the xenon item causing it to migrate to capacitor plate and causing a current in the high voltage load. This current is proportional to the radiation and is fed to the computer as data for computing the image.
  5. 5. TYPES OF CT SCANNERS • Slip-ring scanners • modern CT scanners are multislice • rows and channels • Three-dimensional (3-D) CT • Four-dimensional (4-D) CT • A dual-source computed tomography (DSCT) system
  6. 6. IMAGE QUALITY AND RESOLUTION • radiation dose, • reconstruction filter • spatial resolution • Z-resolution • Field of view (FOV) CONTRAST THICKNESS SLICE AND QUALITY DATA 50 CM IN DIAMETER
  7. 7. Reported Problem
  8. 8. Issue : Controlling the radiation dose Problem : Radiation overdose Symptoms : hair loss, rashes, headaches, memory loss, confusion, epilation or patchy hair loss Consequece : Overdose might cause cancer (epilation is not related to carcinogenic effect)
  9. 9. Reported news 1. Increased radiation-induced-cancer risk in pediatric patients Factor : Solution : - dose-reduction features geared toward pediatric patients is introduced - Regulatory agencies require CT scanner technicians to use patient size-specific charts - to reduce radiation doses for pediatric patients, reductions in tube current and gantry speed is introduced scanning children protocol = scanning adult protocol No difference in patient sizes and transmitted x- ray intensities
  10. 10. Reported news 2. Unexpectedly wide variations in the mean dose delivered to patients for the same studies Causes : a. unnecessary testing could cause an overexposure to radiation b. System problems c. communication breakdowns that result in repeat CT scans 2. Unexpectedly wide variations in the mean dose delivered to patients for the same studies Causes : a. unnecessary testing could cause an overexposure to radiation b. System problems c. communication breakdowns that result in repeat CT scans Reported news
  11. 11. PURCHASE CONSIDERATION 1. Upgrade their CT capabilities - anticipate a need to upgrade their CT capabilities in the future. - 10-slice CT scanner 16 slices - 40-slice system 64-slice system why need to upgrde early? - buying lower-specification equipment and upgrading later will be more expensive Upgrade to full-spec
  12. 12. 2. air-conditioned computer rooms (necessary in some cases) why? - severely compromises the reliability of the scanner system and ultimately shortens its useful life 3. Conditioning the electrical power supply - make artifact-free images often depends strongly on the electrical power 4. Surge suppressors and means for automatic disconnection in the event of power failure must be installed
  13. 13. 5. Enviromental considertions - reduce the use of rare metals during construction. 6. Cost considertions Should purchase service contract preventive maintenance will be performed at regular intervals unexpected maintenance costs can be reduced
  14. 14. STAGE OF DEVELOPMENT • Reduced radiation dose • Improved image quality • Wider coverage (more slices) • Perfusion studies • Interventional CT • Dual-energy CT
  15. 15. BENCHMARK
  16. 16. IPM FREQUENCY

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