Nuclear medicine in general practice Dr Reza Garzan MD, FRACP, FAANMS
• Myocardial perfusion study • Bone scans in general practice • Thyroid scans in general practice
Gamma camera
Detection of gamma rays
Myocardial perfusion Imaging
How is it performed? Rest/Stress protocol : Radiopharmaceutical injected at rest and then post stress. Same day or two day protocol
Radiopharmaceuticals Tc-99m Sestamibi (MIBI) • Sestamibi (MIBI) : Lipophilic agent, diffuses from blood into the myocardial cell and is retained in mitochondria • Tc-99m : Short physical half life of 6hrs , good energy gamma rays ( better quality pictures)
Radiopharmaceuticals Thallium (TI-201): • Behaves physiologically much like K ion, and is transported across the myocardial cell membrane via Na-K ATPase • Long half life and low energy photons, so much less commonly used nowadays
Modes of stress • Exercise • Pharmacologic • Vasodilator ( Adenosine, Dipyridamole) : Dilate the coronary arteries, but the stenosed vessels are not able to dilate as much as normal coronary arteries are able to. Contraindicated in asthma and severe COPD. • Dobutamine : Sympathomimetic
ACCF/ASNC/ACR/AHA/ASE/SCCT/SCMR/SNM 2009 Appropriate Use Criteria for Cardiac Radionuclide Imaging J Am Coll Cardiol . 2009;53(23):2201-2229. doi:10.1016/j.jacc.2009.02.013
Ischemic cascade
What information do we get from MPS? • Perfusion (rest and stress) • Wall motion (rest and stress), systolic function, LVEF • Symptoms • If exercise, exercise capacity • ECG changes
Cardiac planes
• 67-year-old-man, with episodes of chest pain at rest
• 74- year-old, with DM and exertional chest and throat pain, unable to complete exercise stress test
• Moderate to large amount of reversible ischemia in LAD territory
Small MI in distal LAD territory
Prognostic value of normal ( low -risk) and moderately to severely abnormal (high-risk) myocardial perfusion SPECT in estimating annual rates of cardiac death and nonfatal myocardial infarction
• Bone Scans
• Radiotracer injected, ( Tc-99m HDP) • Early phase images immediately ( presence or absence of hyperaemia/normal or abnormal vascularity) • Delayed phase images in about 3-4 hrs ( osteoblastic activity)
Common applications of bone scans in general practice • Stress fractures • Sports injuries • Suspected fractures with normal x-ray • Arthritis/assessment of facet joint arthropathy • Osteomyelitis • Staging and restaging of prostate, breast and lung cancers • Metabolic bone disease e.g. Paget’s disease • Assessment of painful THR and TKR
Normal whole body bone scan
Case 1 • 50 year old female, pain in bilateral hands , history of fall 4 days back on outstretched hands. Xray : normal
Blood flow and blood pool images
Delayed images
SPECT/CT
• Fracture of bilateral trapezium
Case 2 • 76 year-old female, active walker, pain in the left foot since 3/52, ? Stress Fx
Blood flow and blood pool images
Blood pool images
SPECT/CT
• Active arthritis of tarsometatarsal joint
Case 3 • 85-year-old female, Chronic ulcer in the left foot, close to 1 st MTP joint.
Blood pool images
Delayed images
SPECT/CT
• Osteomyelitis of the distal left 1 st metatarsal bone
Case 4 • 47 -year-old male, right 2 nd metatarsal pain after a long walk
Blood flow and blood pool images
Delayed images
SPECT/CT
• Stress fracture of distal right 2 nd metatarsal
Case 5 • 52 year old female, with back pain for investigation
Delayed SPECT/CT images
• Intensely increased radiotracer uptake in the left L5/S1 facet joint, consistent with left L5/S1 facet joint arthropathy • Can be useful for investigation of cervical facet joint arthropathy too.
Case 6 • 68-year-old man with right foot and heel pain after long walk.
• Right Achilles tendon enthesopathy
Thyroid scans • Thyrotoxicosis • Assessment of thyroid nodules
Radiopharmaceutical : Tc-99m Pertechnatate ( TcO4)
• 69 year-old man presenting with thyrotoxicosis
• Hot autonomous functioning nodule
• 65 year-old female, presenting with thyrotoxicosis
• Graves’ disease • Positive TSH receptor antibodies can confirm the diagnosis
• 30-year-old female presenting with post- partum hyperthyroidism
Thank you!
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