Nuclear Medicine Spring 2009 FINAL

2 NM Team Nuclear medicine MD Nuclear medicine MD Physicist Physicist Pharmacist Pharmacist Technologist Technologist Patient Patient

3 Principles of NM Uses radiopharmaceuticals for diagnosis, therapy and medical research Uses radiopharmaceuticals for diagnosis, therapy and medical research Small amounts of radioactive material used Small amounts of radioactive material used Sometimes no more than that received in CT or fluoroscopy Sometimes no more than that received in CT or fluoroscopy Studies physiology Studies physiology Rather than structural appearance Rather than structural appearance

4Tracers Radioactive material that can be: Radioactive material that can be: Injected, ingested or inhaled Injected, ingested or inhaled Different tracers for different body parts Different tracers for different body parts organ-, tissue-, or even cell-specific organ-, tissue-, or even cell-specific They produce gamma-ray emissions from within organ being studied They produce gamma-ray emissions from within organ being studied Gamma or scintillation camera transforms emissions into images Gamma or scintillation camera transforms emissions into images Provides information about function Provides information about function

5 Modality Comparisons PET and SPECT for physiology PET and SPECT for physiology X-ray measures structure, size and position of human anatomy X-ray measures structure, size and position of human anatomy CT creates cross sectional images of anatomy CT creates cross sectional images of anatomy What do all of these modalities have in common? What do all of these modalities have in common?

6 Atom Components & Isotopes

7 Physical Principles of NM Radioactivity Radioactivity Radiation of energy from the nucleus of atom Can be in the form of alpha, beta particles or gamma rays from the nucleus

8 Basic Nuclear Physics Nuclide Nuclide Atom with a particular arrangement of protons and neutrons in the nucleus Atom with a particular arrangement of protons and neutrons in the nucleus Radionuclide Radionuclide Unstable nucleus that transmutes by way of nuclear decay (return to ground state) Unstable nucleus that transmutes by way of nuclear decay (return to ground state) Decay Decay Is the atoms attempt to regain stability Is the atoms attempt to regain stability By emission of alpha, beta and gamma radiation By emission of alpha, beta and gamma radiation Different for each type of radionuclide Different for each type of radionuclide

9 Half Life Physical time it takes for a quantity of radionuclide to decrease to ½ its original activity Physical time it takes for a quantity of radionuclide to decrease to ½ its original activity Radionuclides half life can range from milliseconds to years Radionuclides half life can range from milliseconds to years NM radionucldies range from hours to days NM radionucldies range from hours to days

10 Nuclear Pharmacy Radiopharmaceutical Radiopharmaceutical Radionuclide Radionuclide Pharmaceutical Pharmaceutical Technetium -99 Technetium -99 Short ½ life of 6.04 hours Short ½ life of 6.04 hours Low energy gamma photon Low energy gamma photon

11 Radiation Safety Radiopharmaceuticals must be sterile Radiopharmaceuticals must be sterile Prep area must have isolated ventilation Prep area must have isolated ventilation Protective measures when administering or handling Protective measures when administering or handling Spills must be cleaned immediately Spills must be cleaned immediately Dosimetry devices Dosimetry devices Hands and badges Hands and badges

12 Modern Day Gamma Camera Scintillate means: to emit light Scintillate means: to emit light Ionizing radiation causes certain materials to glow Ionizing radiation causes certain materials to glow Scintillation detector Scintillation detector Detects radiation by observing the emission of light photons emitted by the materials Detects radiation by observing the emission of light photons emitted by the materials PMT detect and convert light photons emitted from the crystal into and electronic signal that amplifies the original photon signal PMT detect and convert light photons emitted from the crystal into and electronic signal that amplifies the original photon signal It is then sent to be viewed It is then sent to be viewed

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14 Detectors

15 Collimators Keep scattered rays from entering the scintillation crystal Keep scattered rays from entering the scintillation crystal Absorbs scattered gamma rays Absorbs scattered gamma rays Resolution and sensitivity Resolution and sensitivity Physical characteristics Physical characteristics Made of material with high atomic number Made of material with high atomic number Lead Lead

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17 Crystals Sodium iodide Thallium Sodium iodide Thallium Thick layer of crystals Thick layer of crystals High energies High energies Decreased resolution Decreased resolution Thin layer of crystals Thin layer of crystals Lower energies Lower energies Increased resolution Increased resolution

18 Photomultiplier Tubes Attached to the back of the crystals Attached to the back of the crystals Detect and convert light photons into and electronic signal that amplifies the original photon signal Detect and convert light photons into and electronic signal that amplifies the original photon signal About in a gamma camera About in a gamma camera Light pipe Light pipe Like a focusing device Like a focusing device

19 Put it all Together

20 Computer Acquires and processes data received from camera Acquires and processes data received from camera In a time frame In a time frame Post-processing Post-processing Adjust contrast and density Adjust contrast and density Records Records Dosage Dosage Quality control Quality control

21 Types of Camera Systems Single detector Single detector Dual head Dual head Triple head Triple head

22 Single Head Detector

23 Dual Head Detector

24 Triple Head Detector

25 Imaging Methods Static Static Whole- Body Whole- Body Dynamic Dynamic SPECT SPECT Co-registration Co-registration PET PET

26 Static Single image of a particular structure Single image of a particular structure Demonstrates radiopharmaceutical distribution Demonstrates radiopharmaceutical distribution Ex: lung scans, spot bone scans images, thyroid images Ex: lung scans, spot bone scans images, thyroid images Obtained in various orientations, anterior, posterior, and oblique Obtained in various orientations, anterior, posterior, and oblique Low activity levels Low activity levels Generally 30 seconds to five minutes Generally 30 seconds to five minutes

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28 Whole Body Entire body or a large section of body Entire body or a large section of body Primarily used for Primarily used for Bone scans Bone scans Tumor scans Tumor scans Abscess imaging Abscess imaging Clinical and research applications Clinical and research applications

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31 Dynamic Timed record of distribution of radiopharmaceutical Timed record of distribution of radiopharmaceutical Commonly used for Commonly used for Cardiac studies Cardiac studies Hepatobiliary studies Hepatobiliary studies Gastric emptying studies Gastric emptying studies

32 Dynamic Renogram

33 Dynamic Venogram

34 SPECT Images similar to CT & MRI Images similar to CT & MRI thin slices through a particular organ thin slices through a particular organ 360 degree rotatator heads allows for: 360 degree rotatator heads allows for: Coronal, planar and 3D imaging Coronal, planar and 3D imaging Ex: cardiac perfusion, brain, liver and bone studies Ex: cardiac perfusion, brain, liver and bone studies

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36 SPECT and CT combination Merges SPECT functional testing with CT anatomic landmark images Merges SPECT functional testing with CT anatomic landmark images Statistics show Statistics show 25-30% change of treatment options from what would have been done with SPECT alone 25-30% change of treatment options from what would have been done with SPECT alone

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39 PET Resolution is 2-10 better than SPECT Resolution is 2-10 better than SPECT Radiopharmaceuticals Radiopharmaceuticals Minimal alteration in homeostasis Minimal alteration in homeostasis Very small amounts used Very small amounts used Co-registration being done with CT & MRI Co-registration being done with CT & MRI Almost all new machines are fused with a CT scanner Almost all new machines are fused with a CT scanner

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