NM Protocols

NM Protocols

1. CSF

   • Pathologies
     • Normal Pressure Hydrocephalus (NPH)
       • Diminished CSF absorption at arachnoid villa in dural sinus causing increased pressure
       • Distended ventricles distort periventricular limbic system - causes dementia symptoms
     • Leakages
       • Causes: Trauma, surgery, hydrocephalus, congenital defects
       • Symptoms: Rhinorrhoea, Otorrhoea, headache, drowsiness, meningitis, neurological changes and air in the brain
   • Methods
     • Method 1 (NPH and leakages)
       • 200MBq of 99mTc-DTPA via lumbar puncture (intrathecal)
         • posterior lumbar - 2mins, 128 matrix
           • Ant/post and Lt/Rt lat head images (128matrix) @ 2,6,24hours
             • 2 and 6 hours image for 2mins
             • 24hours image for 5mins
     • Method 2 (VP shunts)
       • 40MBq of 99mTc-DTPA: Admin via shunt reservoir
         • Ant Head Dynamic: 1min/frame for 30mins (128 matrix)
         • Planars (ant and rt lat abdomen)
           • 2mins, 128 matrix
             • @30mins
             • @2 hours
             • @4 hours
           • 10mins, 128matrix
             • @24 hours
   • VP shunt
     • Normalises intracranial pressure by regulating flow of CSF
     • Drains CSF from lat ventricle to peritoneal space (or pleural space)

2. Brain

   • Methods
     • Standard
       • 800MBq of Neurolite or ceretec (IV), patient at rest
       • 45mins post injection, standard SPECT (but with a zoom of 2)
     • Brain Death
       • Dynamic: ant/post, 3sec/frame for 20 frames (128matrix) - followed by standard brain scan
     • Diamox challenge
       • Day 1: standard scan
       • Day 2: 1ml of diamox given half an hour before a standard scan
   • Pathologies
     • Alzheimer's
       • hypoperfusion in the parietotemporal lobes
       • Forgetfulness, cognitive impairment, confusion
     • DLB
       • Tremors,visual disturbances, slowness, motor disfunction
       • Similar to AD but with occipital and cerebellar involvement
     • Vascular Dementia
       • heterogenous uptake within the brain
     • TIA
       • Normal on first scan but hypoperfusion after diamox challenge
     • Epilepsy
       • 2 scans 48hrs apart (ictal/interictal)
         • Ictal: localised hyperperfusion
           • Interictal: normal perfusion

3. Parathyroid

   • Pathologies
     • Adenoma
       • Symptoms: muscle weakness, abnormal reflexes, depression of the nervous system, fatigue, confusion, kidney stones, metastatic calcification and anorexia
       • Diagnosis
         • Increased serum PTH and Ca2+
         • Decreased serum inorganic phosphate
   • Methods
     • Subtraction (supine, neck extended)
       • 1. Thyroid Scan
         • 40MBq of pertechnetate
         • Image 20mins post IV
           • Ant Neck, 4mins (zoom of 2), 128 matrix.
       • 2.Early MIBI
     • Washout/Delayed (supine, neck extended)
       • Early @ 15mins
         • Ant Static, 128matrix
           • Neck, 10mins (zoom of 2)
           • Neck and chest, 5mins
         • SPECT/CT
           • 64 projections @40secs per projection
       • Delayed @ 2 hours
         • *Repeat early images (if no washout repeat at 3 or 4 hours)
   • Sestamibi
     • 600MBq
     • Taken up by mitochondria in the thyroid and parathyroid.
     • Retention is higher in adenomas (due to a greater negative mitochondrial and transmembrane electric potentials)
     • Is a lipophilic cation

4. Lymphatics

   • RP's (99mTc)
     • Sulphur colloid
       • large particle size (50-2000nm), slow clearance
     • Antimony sulphide colloid
       • Agent of choice! Migrates rapidly through lymph vessels, good node retention, comprehensive and accurate
       • fairly uniform and ideal size (10-15nm), colloid is stable
       • Add 1GBq of pertechnetate in 1ml of saline and then HCl to a vial containing antimony trisulphide. Heat in a boiling water bath for 30mins then allow to cool. Add a phosphate buffer (pH 5.5-6.5). Filter through a 0.2micro(m) filter.
     • HSA
       • poor retention
     • Rhenium colloid
       • ultrafiltered, 50nm range
   • Pathologies
     • Lymphoedema
       • Lymphatic dysfunction resulting in accumulation of interstitial fluid containing high molecular weight proteins
       • Symptoms: mass swelling, fatigue, physical impairment, bacterial or fungal infections are common
   • Methods
     • Legs
       • 10cm/min (256*1024matrix)
       • 4 scans after injection followed by repeat scans at 2 and 4hrs
     • Sentinel node
       • supine-arm above head
       • dynamic: 30 frames @ 60sec per frame
         • Statics: ant/post/lats 2mins, 128matrix
           • SPECT: 64 projections @ 40sec per projection, 128matrix

5. Infection

   • Pathologies
     • Osteomyelitis
       • 3 phase bone scan first followed by a white cell or gallium scan (if bone scan is positive)
     • Inflammatory Bowel Disease
       • Crohn's Disease
       • Ulcerative Colitis
     • Pyrogen of Unknown Origin
       • bacteria, viruses, cancer, allergic reactions, trauma or autoimmune disease (Induces a fever)
       • stimulates the release of prostaglandin E2 which acts on the hypothalamus
   • RP's
     • 67Ga Citrate
       • Binds to transferrin then migrates to infection site and binds to lactoferrin (large amounts in abcess fluid)
       • Liver, spleen, kidney, adrenal, bowel and skeletal uptake
     • WBC
       • 111In (20MBq)
         • ADVANTAGES: doesn't elute from leukocyte cytoplasm, no bowel accumulation, no leukocyte damage, long half life, can do dual imaging
         • DISADVANTAGES: cyclotron produced, expensive, poor imaging characteristics, auger electrons, only low dose possible
       • 99mTc-HMPAO (800MBq)
         • ADVANTAGES: Short half life, readily available, good imaging characteristics
         • DISADVANTAGES: elutes from leukocyte cytoplasm, hepatic and renal clearance, leukocyte damage, short half life, short shelf life
   • Methods
     • White Cell
       • 20MBq of 111In WBC or 800MBq of 99mTc (HMPAO) WBC's
         • Early (4hrs post admin)
           • Planar, 128 matrix
             • 10mins for 111In
             • 5mins for HMPAO
         • Delayed (24hrs post admin)
           • Planar: 10mins, 128 matrix, FOV: affected region
           • SPECT: 64 projections at 40sec/projections
     • IBD
       • 20MBq of 111In (IV)
       • Imaging at 30, 2, 4, 24hrs
         • Abdo/pelvis (ant/post/lats) 10mins, 128 matrix
     • Post-Surgical
       • Ant/Post and Lats over the effected area
         • Imaging @ 2, 4, 24hrs
           • 20MBq of 111In WBCs (IV)
             • 10mins, 256 matrix
           • 800MBq 99mTc WBCs (IV)
             • 5mins @ 2 and 4hrs, 256 matrix
               • 10mins @ 24hrs, 256 matrix
     • Pyrogen of Unknown Origin
       • 111In WBC
         • 20MBq (IV)
         • WB scan 8cm/min, 256*1024
           • 4 and 24hours
       • 67Ga Citrate
         • 400-600MBq (IV)
         • WB scan 10cm/min, 256*1024
           • 48hours