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NUCLEAR IMAGING   Prepared By:   Muhammad Yaseen   Trainee Med. Physicist   Radiology Department   Mail: myaseena@hotmail....
Contents Introduction Advantages Of Nuclear Imaging Radiography Vs Nuclear Imaging Radioisotopes used in NM Radiophar...
INTRODUCTION DEFINITION:           Nuclear imaging is a method of producing  images by detecting radiation from different...
Advantages Of Nuclear Medicine Target tissue function is investigated. All similar target tissues can be examined during...
Radiographic Vs Nuclear ImagingRadiographic Imaging         Nuclear ImagingTransmission Type Image   Emission Type Of Imag...
Radioisotopes Used In Conventional          Nuclear Medicine An ideal radionuclide has following properties:  -      A sh...
For Imaging Technetium Is Used Extensively, As It Has                Following PropertiesA. Technetium is a gamma emitter....
Tc-99m
Main Indications Of Nuclear Imaging Nuclear imaging technique is used for assessing function of:   - Salivary gland as sa...
Principle Of Nuclear Imaging Technique THE STEPWISE PROCEDURE OF NUCLEAR IMAGING:Radionuclides are administered via vein ...
Bone Scan & Thyroid Scan Images
PharmaceuticalOrgan                      Pharmaceutical          Tc-99m pertechnetate Brain    Tc-99m DTPA          Tc-99m...
General Imaging Consideration
GAMMA CAMERA A gamma camera, also called a scintillation camera or Anger camera, is a device used to image gamma emitting...
Gamma Camera Components Collimator Crystal PM Tubes Analog To Digital Convertor X And Y Positioning Circuits A Visua...
Collimator The collimator can be made from lead foil. The collimator stops about 99.9% of the available photons. The wa...
Types Of Collimator Parallel Hole Collimator Converging Collimator Diverging Collimator Pin Hole Collimator
Parallel Hole Collimator LEGP (low energy general  purpose) or LEAP (low  energy all purpose). To increase the resolutio...
Parallel Hole Collimator To image higher energy  isotopes such as Ga-67 or I-131, the collimator needs to have thicker se...
Pin Hole ,Converging &Diverging           Collimators Converging
Crystal (NaI) The γ-rays that pass through the collimator then strike scintillation crystal. Made up of sodium iodide wi...
Photo Multiplier Tube Extremely sensitive detector of light in the ultraviolet,  visible and near infrared Multiplies th...
Components Of PMT Made of a glass  vacuum tube Photocathode Several dynodes One anode
How It Works
Analog To Digital Convertor The signals from photomultiplier tubes go through an analog to  digital converter (ADC) This...
X And Y Position Circuit
Further Developments in Radioisotope     Imaging Techniques Include SPECT (single photon emission computed tomography)   ...
Single Photon Emission Computed           Tomography SPECT is a method of acquiring tomographic slices  through a patient...
Applications of SPECT Heart Imaging Brain Imaging Tumor detection SPECT can be used to detect tumors in cancer patients...
Advantages of SPECT Better detailed resolution Enhanced contrast Localization of defects is more precise and more clear...
Limitation Of Nuclear Medicine Poor image resolution – only minimal information of target  tissue is obtained. The radia...
Safety Precautions Injected patient should avoid to keep away from everyone  but specially from children and pregnant wom...
Summary
References Medical instrumentation by :  Jennifer Prekeges The essential physics of medical imaging by:  Bush Berg
Muhammad yaseen
Muhammad yaseen
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Muhammad yaseen

  1. 1. NUCLEAR IMAGING Prepared By: Muhammad Yaseen Trainee Med. Physicist Radiology Department Mail: myaseena@hotmail.com
  2. 2. Contents Introduction Advantages Of Nuclear Imaging Radiography Vs Nuclear Imaging Radioisotopes used in NM Radiopharmaceuticals Gamma Camera SPECT Safety Summary
  3. 3. INTRODUCTION DEFINITION: Nuclear imaging is a method of producing images by detecting radiation from different parts of the body after a radioactive tracer material is administered. The images are recorded on computer and on film. The nuclear imaging physician interprets the images to make a diagnosis. Radioactive tracers used in nuclear medicine are, in most cases, injected into a vein.
  4. 4. Advantages Of Nuclear Medicine Target tissue function is investigated. All similar target tissues can be examined during one investigation, e.g. the whole skeleton can be imaged during one bone scan. Computer analysis and enhancement of results are available.
  5. 5. Radiographic Vs Nuclear ImagingRadiographic Imaging Nuclear ImagingTransmission Type Image Emission Type Of ImageMorphologic Imaging Functional ImagingHigh Resolution Low ResolutionUse X-rays Use Gamma RaysShort Time Long Time
  6. 6. Radioisotopes Used In Conventional Nuclear Medicine An ideal radionuclide has following properties: - A short half life. - Emits γ-rays. - Capable of binding to a variety of biomolecules. Examples of radionuclides together with their target tissues or target diseases: - Technetium (99mTc) – Salivary glands, thyroid, bone, blood, liver, lung & heart. - Iodine (131I ) – Thyroid - Gallium (67Ga) – Tumors & inflammation
  7. 7. For Imaging Technetium Is Used Extensively, As It Has Following PropertiesA. Technetium is a gamma emitter. This is important as the rays need to penetrate the body so the camera can detect them.B. It has a short half life of 6 1/2 hours. Thus the amount of radioactive exposure is limited.C. It is readily attached to a variety of different substances that are concentrated in different organs, e.g. - Tc + MDP (methylene disphosphonate) in bone - Tc + sulphur colloid in the liver and spleen.D. It is easily produced, as and when required, on site.
  8. 8. Tc-99m
  9. 9. Main Indications Of Nuclear Imaging Nuclear imaging technique is used for assessing function of: - Salivary gland as salivary scans - Brain - Thyroids - Heart - Lungs - Gastro-intestinal system It is also used for diagnosis of: - Metastatic diseases - Bone tumors as bone scans
  10. 10. Principle Of Nuclear Imaging Technique THE STEPWISE PROCEDURE OF NUCLEAR IMAGING:Radionuclides are administered via vein or mouthThey distribute in the body according to their strength for particular tissues so called target tissues. Radionuclides emit gamma radiations. Detected by γ-scintillation cameraWhich forms images showing location of radionuclides in the body.
  11. 11. Bone Scan & Thyroid Scan Images
  12. 12. PharmaceuticalOrgan Pharmaceutical Tc-99m pertechnetate Brain Tc-99m DTPA Tc-99m glucoheptonateCardiac Tc-99m pyrophosphate Liver Tc-99m sulfur colloid Tc-99m DTPAKidney Tc-99m DMSA Tc-99m glucoheptonate I-131Thyroid I-131 Hippuran
  13. 13. General Imaging Consideration
  14. 14. GAMMA CAMERA A gamma camera, also called a scintillation camera or Anger camera, is a device used to image gamma emitting radioisotopes, a technique known as scintigraphy. These cameras capture photons and convert them to light and then to a voltage signal. These signals are reconstructed to an image that shows distribution of radionuclide in the patient.
  15. 15. Gamma Camera Components Collimator Crystal PM Tubes Analog To Digital Convertor X And Y Positioning Circuits A Visual Display With Display Electronics
  16. 16. Collimator The collimator can be made from lead foil. The collimator stops about 99.9% of the available photons. The walls of each channel in the collimator are called septa, and if a photon manages to penetrate the wall, it is called septal penetration.
  17. 17. Types Of Collimator Parallel Hole Collimator Converging Collimator Diverging Collimator Pin Hole Collimator
  18. 18. Parallel Hole Collimator LEGP (low energy general purpose) or LEAP (low energy all purpose). To increase the resolution, smaller diameter holes are needed. To increase sensitivity, the holes need to be wider.
  19. 19. Parallel Hole Collimator To image higher energy isotopes such as Ga-67 or I-131, the collimator needs to have thicker septa in order to stop penetration. This produces a heavier collimator with lower sensitivity.
  20. 20. Pin Hole ,Converging &Diverging Collimators Converging
  21. 21. Crystal (NaI) The γ-rays that pass through the collimator then strike scintillation crystal. Made up of sodium iodide with trace amount of thallium. This crystal shows florescence when it absorbs γ-rays. These flashes of light are detected by photomultiplier tubes coupled to the crystal.
  22. 22. Photo Multiplier Tube Extremely sensitive detector of light in the ultraviolet, visible and near infrared Multiplies the signal produced by incident light by as much as 108 • single photons can be resolved High gain, low noise, high frequency response, and large area of collection A tiny and normally undetectable current becomes a much larger and easily measurable current
  23. 23. Components Of PMT Made of a glass vacuum tube Photocathode Several dynodes One anode
  24. 24. How It Works
  25. 25. Analog To Digital Convertor The signals from photomultiplier tubes go through an analog to digital converter (ADC) This component is used to convert the analogue information produced by the imaging system so that it is coded in the form of binary numbers. In this way the analog signal is digitalized & used to produce image by computer
  26. 26. X And Y Position Circuit
  27. 27. Further Developments in Radioisotope Imaging Techniques Include SPECT (single photon emission computed tomography) And PET (Positron emission tomography)
  28. 28. Single Photon Emission Computed Tomography SPECT is a method of acquiring tomographic slices through a patient. Most gamma cameras have SPECT capability. In this technique either a single or multiple gamma cameras is rotated 360 degrees about the patient. Image acquisition takes about 30 – 45 min.
  29. 29. Applications of SPECT Heart Imaging Brain Imaging Tumor detection SPECT can be used to detect tumors in cancer patients in the early stages. Bone Scans
  30. 30. Advantages of SPECT Better detailed resolution Enhanced contrast Localization of defects is more precise and more clearly seen. Extend and size of defects is better defined.
  31. 31. Limitation Of Nuclear Medicine Poor image resolution – only minimal information of target tissue is obtained. The radiation dose to the whole body can be relatively high. Images are not usually disease-specific. Difficult to localize exact anatomical site of source of emission. Facilities are not widely available.
  32. 32. Safety Precautions Injected patient should avoid to keep away from everyone but specially from children and pregnant women Only authorized users are allowed to handle the source. Do not look directly into bore hole of the source holder or cover it with any part of your body. Use Lead Apron, lead goggles and lead thyroid shield
  33. 33. Summary
  34. 34. References Medical instrumentation by : Jennifer Prekeges The essential physics of medical imaging by: Bush Berg

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