Nuclear Medicine, PET, SPECT/CT Imaging Questions and Answers

Nuclear Medicine, PET, SPECT/CT Imaging Questions and Answers What does nuclear medicine evaluate? How organs are functioning (physiology) to help detect pathology at the molecular level - differs from other modalities because it doesn't show changes in anatomy Where is the preparation of pharmaceuticals done? In the radiopharmacy Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:00 / 0:15 Full screen Brainpower Read More What are the 2 parts of radiopharmaceuticals? The drug portion (goes to the source), and the radioactive isotope (so we can see it) How can radiopharmaceuticals be administered? Is there any pain or side effects associated with the drugs? Injected into a vein in the arm, orally, or inhaled depending on the study - no pain or side effects What is the most common nuclide? What E does it have? technetium 99-m (Tc-99m), 140 keV What is the half life of technetium 99-m? How long does it take to be completely voided? 6 hour half life, 24 hours to be completely voided How are images obtained? - gamma radiation is emitted from within the patient (as opposed to through the pt) - emission of gamma photon represents the location of the radionuclide w/in the structure - information emitted is captured by a detector - function determined by intensity of gamma radiation emitted What are contraindications for a nuclear medicine study? - no barium for 48 hours - no previous NM tests What is the appropriate preparation for a NM test? Fasting and stopping medications Why are patients allowed to stay clothed? Because you're using higher energy photons so clothing doesn't leave artifacts What is the range of exam lengths for NM testing? 30 min to several days What are some test-specific history questions? Broken bones, bone disease, renal disease, surgery to the bones, cancer, etc. What do hot spots demonstrate? Areas of increased uptake What do cold spots demonstrate? Areas of decreased uptake What does CNS NM testing determine and measure? What radionuclide is used? What is the diagnostic correlation? Brain viability and measures the regional cerebral blood flow to assess if there is sufficient activity to sustain life - 99m Tc-Bicisate (Neurolite) - EEG What does pulmonary system NM test used to diagnose? What are you looking for? What radionuclide(s) are used? What is the diagnostic correlation? Used to diagnose pulmonary embolism by looking at both the ventilation/air flow and perfusion/b+ flow of the lungs - looking for a "mismatched" defect - 99 Tc-DTPA and 99m Tc-MAA - CXR, CT, US (to assess for CVT), MRA (Normal pulmonary scan) What are the 2 phases of pulmonary system NM testing? Ventilation - assess air flow to the lungs by breathing in a radioactive aerosol Perfusion - assess b+ flow to the lungs by injecting the radioactive tracer IV (Scan w/ pulmonary embolism) What is myocardial perfusion imaging differentiating? What is the diagnostic correlation? Differentiates between ischemia and infarction - aids in the diagnosis and mgmt of CAD regionally and globally - diagnostic correlation: coronary angiography, exercise stress test, echocardiogram, b+ test (cardiac enzymes) - SPECT/CT What are examples of therapeutic uses of myocardial perfusion imaging? CABG, angioplasty/stent, pacemaker, valve replacement Stress/Rest Tests What different formats can images be obtained in? Planar, dynamic, and 3D What radiopharmaceuticals does SPECT imaging use? The same as NM What does SPECT stand for? Single photon emission computed tomography What cameras does SPECT use? The same as regular NM - the cameras take planar images at different angles around the patient and the images can be reconstructed How can planar SPECT images be reformatted? By using the back projection, the computer will process the data and reconstruct the info into layers/slices - similar to CT post proc What are advantages of SPECT over PET? - requires less space and consumables - no cyclotron required - lower operating costs What is the exponential attenuation law? Gamma rays that originate from deep w/in a patient will undergo interactions as they travel resulting in a lower detection efficiency of photons What modality is used to determine patient-specific attenuation correction factors? CT Why is CT the method of choice for attenuation correction? - speed - decreased image noise - decreased patient dose Is a CT image of attenuation correction diagnostic? No - the image produced still allows for correlation of anatomical info with the functional info of the nuc med scan What are advantages to SPECT/CT? - SPECT/CT allows for small injuries/#s to be discovered and treated earlier than traditional xray What does PET stand for? positron emission tomography