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GI system

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					                GI system
GI system consists of:
  >Gastrointestinal tract
  >Alimentary canal
  >Several accessory organs
>Alimentary canal provides routes of intake
 for nourishment, digest, absorb nutrients, and
 eliminate waste. Consists of mouth, pharynx,
 esophagus, stomach, small intestine, and
 large intestine.
               GI System
 Accessory organs:
  >salivary glands, pancreas, liver and
   gallbladder .
  >Variety of radionuclides are available
   for evaluation of the GI tract, and
   specific organs.
               Gi system
 Salivarygland imaging is also known as
 nuclear sialography
 >salivary glands indiscriminately trap
  a number of ions and iodides
 >Tc99m pertechnetate is actively
   excreted by glands
  >production and excretion can be
    evaluated by using Tc99m
                GI system
 No patient prep needed
 Patient seated facing camera
 LEAP collimator
 1-5 mCi Tc99m injected.
 Dynamic images acquired 1-2 sec per/fr.
 Static images anterior, laterals
 Lemon juice (diluted) is “swished” in mouth
 Additional views are obtained to see
  washout of Tc99m from salivary glands
                Gi system
 Esophageal   transit studies useful as non-
  invasive screening for esophageal motility
  disorders.
 Good for esophageal motor disorder, not
  good for anatomic detail.
 Barium swallow or endoscopy better for
  anatomical detail
                   Gi system
   Imaging procedure:
     >2 hrs NPO
     >mix 300uCi Tc99m sulfur colloid in 15ml
      water
     >patient placed supine, anterior thorax
      placed under camera with stomach in
      FOV.
     >radiopharmaceutical administered through
      straw, entire volume held in mouth until
      instructed to swallow.
               Gi system
 Imaging procedure:
  >imaging begins, patient told to swallow
  >imaging is acquired at .25sec per/fr
   for 1min
  >15sec per/fr for remaining 9min
  >patient told to swallow continuously for
   entire test.
                Gi system
 Gastroesophageal     reflux
 Imaging procedure:
   >NPO for 8hrs prior to study
   >300uCi Tc99m sulfur colloid in 150ml
    orange juice and 150ml 0.1
    hydrochloric acid
   >patient fitted with abdominal binder.
               Gi system
 Imaging  procedure:
  >positioned supine under camera
  >binder cuff increased at different
   intervals
  >imaging begins no more than 10mins
   after drink is ingested
  >imaging occurs for 30sec at different
   inflation intervals 0, 20,40 etc.
                Gi system
 Gastric emptying studies are done to
  evaluate the function and motility of the
  stomach
 When other radiographic or endoscopic
  exams cannot explain clinical signs
 Mechanical and nonmechanical motility
  disorders can be summarized on Pg 457
  table 16-1
               Gi system
 Imaging procedure:
  >patient must be NPO 8hrs prior
  >in-vivo and in-vitro labeling of chicken
   liver
  >500uCi Tc99m sulfur colloid injected
   into two raw eggs than cooked
  >patient eats cooked egg sandwich.
  >liquid portion is prepared with 125uCi of
   In111 in tap water.
               Gi system
 Patienteats and drinks both prepared
  substances
 Imaging begins with camera peaked at two
  energy settings In111 and Tc99m
 Images last for 60sec at both energies
 Taken every 15mins for 2hours.
 ROI drawn around stomach and counts
  are generated for each image.
                Gi system
 Gastric  emptying using Tc99m sulfur
  colloid (solid phase) Tc99m-DTPA (liquid
  phase)
 Same prep and imaging protocols
  different.
 Gastric and Liquid phase done separately
 Allergy to eggs can use oatmeal, baby
  food, sweet potatoes, beef or chicken liver.
                Gi system
 Dynamic   or static imaging
 Dynamic 60sec/fr for 60-90min
 Static 60-120sec per/fr every 5mins for
  30min. Every 15mins there after, for up to
  3hrs.
 Patient in supine position acquisition
  started as soon as patient is done eating.
 Upon completion ROI drawn around
  stomach and counts are generated.
               Gi system
 Liverand Spleen imaging:
 >evaluation of functional liver disease
  such as, cirrhosis, hepatitis, and metabolic
  disease.
 >evaluation of hepatic lesion for biopsy,
   hepatomegaly, jaundice, ascities, and
   liver enzymes abnormalities.
              Gi system
 Liverand Spleen imaging:
 >Tc99m sulfur colloid and Tc99m albumin
   colloid most commonly used radiopharm.
 >large FOV used to image liver and spleen
  simultaneously.
 >Ga67 and Tc99m labeled RBC’s can also
   help for imaging certain lesions
                Gi system
 Liverand Spleen imaging:
   >good screening test with high sensitivity
    poor specificity.
   >no patient preparation.
   >should be done prior to iodinated or
    barium contrast.
   >barium can result in defects in the liver
    and spleen.
                 Gi system
 Liver  and Spleen imaging:
 Adult dose= 5-10mCi sulfur colloid 1-8mCi
  albumin colloid
 If flow study is needed:
  >position patient (xiphoid process at top of
    FOV)
  >inject and begin imaging immediately.
    blood pool image acquired after flow
                Gi system
 Liver and Spleen imaging:
  >15 min PI static imaging begins.
  >lead marker placed over last costal margin
   for liver
  >anterior, posterior, rt/lt laterals, anterior
    oblique (per protocol posterior oblique)
  >SPECT imaging acquired per protocol
               Gi system
 Liverhemangioma detection
   >Tc99m labeled RBC’s
   >most common benign tumor of the liver
   >discovered through CT or ultrasound
   >radionuclide technique generally 100%
    accurate
   >accurate diagnosis essential,
    inadvertent biopsy could lead
    hemorrhage
                     Gi system
   Liver hemangioma imaging:
    >no patient prep, no radiographic contrast
     media in abdomen
    >post RBC’s labeling, bolus injection of
     15-30mCi Tc99m tagged RBC’s is
      administered.
    >flow (dynamic) study is acquired 1/3 sec
     per/fr. Record blood flow
    >a blood pool image is acquired in anterior,
     posterior, RAO, RT lateral.
               Gi system
      hemangioma imaging:
 Liver
 >1-2 hrs PI SPECT imaging is acquired
 >planar (static) images may be acquired
  same projections as blood pool.
                Gi system
 Gallbladder (Hepatobiliary) imaging:
 >gallbladder concentrates and stores bile
 >located against the visceral wall of the
  gallbladder.
 >bile is received through common hepatic
  duct through the cystic duct
 >upon ingestion of a fatty meal, bile is
  discharged into duodenum to help break
  down food
                Gi system
 Gallbladder(hepatobiliary) imaging:
 >most common radiopharmaceutical
 agents:
        >Tc99m iminodiacetic(Tc99m-IDA)
        >Tc99m hepatoiminodiaetic (HIDA)
        >Tc99m DISIDA
        >Tc99m mebrofenin
 >I-131 rose bengal also used (no longer)
                         Gi system
    Gallbladder (hepatobiliary) imaging:
    >investigating patients with upper abdominal pain
    >clinical indications:
       >acute or chronic cholecystitis
       >calculation of GBEF
       >evaluation of enterogastric reflux (bile)
       >evaluation of biliary surgery (bile leak)
       >jaundice
       >pediatrics: biliary atresia vs neonatal hepatitis
       >evaluation of “cold” defects on liver images.
               Gi system
 Imaging  procedure:
 >patient NPO at least 2hrs prior
 >non-visualization of GB if not NPO
 >pain meds may interfere with transit of
  radionuclide. (morphine, opium )
 >1-10mCi Tc99m-IDA agent given IV
 >imaging is began immediately
 >patient in supine position can be done
  sitting or erect
               Gi system
 Imaging procedure:
 >sequential images are obtained in the
 anterior projection for a minimum of 1hr.
 >gallbladder or biliary ducts fail to be
  visualized in 1hr imaging should be
  continued for up to 4hrs or longer.
 >CCK (cholecystokinin) or morphine may
 be needed in certain situations
                 Gi system
 CCK  is used to stimulate the gallbladder to
  contract when Biliary Dyskinesia is
  suspected
 CCK aids in determining EF of gallbladder
 Morphine is injected if cystic duct is patent
  and no visualization of gallbladder has
  happened.
                Gi system
 Gastrointestinal   Bleeding:
 Small intestine:
  >duodenum, jejunum, and ileum.
  >responsible for digestion, and
 absorption of all nutrients.
>Large intestine:
  >cecum, ascending colon, transverse
 colon, descending colon, sigmoid colon,
 and rectum.
               GI SYSTEM
 Gastrointestinal bleeding indications:
 Detect and localize bleeding sites
  >active or intermittent GI bleeds
  >caused by aspirin, ulcers, perforation,
  cancers, inflammation, diverticula, or
  angiodysplasia.
  > for detection patient must be actively
  bleeding.
                Gi system
 Gastrointestinal  bleeding:
 Radionuclide methods routine in most
  nuclear medicine departments.
 In-vivo and in-vitro tagging.
 Tc99m sulfur colloid
 In-vivo PYP (pyrophosphate) tagged with
  20-30 mCi Tc99m.
 In-vitro labeled RBC’s (Ultratag) tagged
  with 20-30 mCi Tc99m
                Gi system
 Tc99m    SC sulfur colloid 10-20 mCi
  administered
 Most common in-vitro tagged RBC’s
  >1-3ml patient blood is tagged (ultratag)
   with 20-30mCi Tc99m
  >flow may be acquired if actively bleeding
  >static imaging 5,10,15,20, etc. to 60 mins
  >if no bleeding site located delay images
  may be needed
                    Gi system
   Gastrointestinal bleeding:
    >dynamic imaging preferred
    >continuous images acquired at 60sec per/fr for
    1hr.
    >delayed images needed if bleeding site not
    located after 1hr images
    >delayed images can be acquired up to 36hrs.
    >additional views laterals, oblique may also be
    needed to visualize bleed.
         Please stop…….
 ANY QUESTIONS??????
 LIGHTS !!!!!!!

				
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posted:7/28/2011
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