Nuc Med – Flashcard
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What does Nuc Med scans show compared to all other types of scans?
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Physiology, all other scans show anatomy
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How does Nuc Med scans work?
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By the injection or ingestion of radioactive isotopes into the body and the camera detects radiation
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What type of radiation rays does Nuc Med use?
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Gamma, they can only be stopped by lead
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How many CT scans can a person have before it becomes dangerous?
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25 scans
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What is used in Bone scans?
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Tc-MDP (very similar to calcium)
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What does Tc-MDP bind to in bone scans?
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chemically binds to hydroxyapatite crystals to show osteoblast activity
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When would you order a bone scan??
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Cancer, infection, stress fracture, arthritis, localize sites for biopsy
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How does Tc-MDP work with bone scans and metastatic disease?
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the cancer needs more nutrients, uses more calcium, so the isotope goes to that area and is sucked up to make a bright spot METS to the skull, ribs, scapula, pelvis and femurs are common
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What does MUGA stand for
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Multi Gated Acquistion
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When are MUGAs typically ordered
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Calculate Ejection fraction (surgical clearance, chemo pts, MI) , evaluate wall motion, evaluate cardiomyopathy and CHF *oncology to see heart damage during chemo)
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What isotope is used in MUGA
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Tc-RBC
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How does Tc-RBC react with the body?
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Isotope is attached to Patients RBCs - make RBCs radioactive
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MUGA levels - normal
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LVEF 50-70% RVEF 40-60%
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MUGA levels- abnormal
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Abnormal <35% Severe <30%
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Abnormal wall motion with MUGA
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CAD, LV aneurysm
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2 parts to a stress test
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Part 1 shows blood flow to myocardium while at rest Part 2 shows blood flow at peak exercise - where does blood go when heart is stressed Compare images from rest to stress
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Common chemical medications in stress tests
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Adenosine (dilates coronary arteries to stimulate stress) Doubtamine (Increases HR, may inject while on tredmill)
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Steps of a stress test
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Patient starts out walking Speed increases and the angle increases Gives best overall picture of patients health Inject when Target HR is Achieved (220-Age)=THR, Qulaity test is 85%-100% of THR
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What do you look for on a stress test?
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Spots that look "cold" that dont have the same intensity in color that suggest decreased blood flow
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What supplies the apex with blood?
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The left anterior descending, Right coronary artery, posterior descending
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What supplies the septum
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Left anterior descending
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What supplies the anterior heart
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the left anterior descending
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what supplies the lateral heart
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the left circumflex
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What supplies the inferior heart
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the Right Coronary Artery
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Fixed Defect on Stress test
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a cold spot at rest; indicates MI or dead tissue
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Stress Defect on stress tests
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ischemia to muscle send to cath lab or surgery
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What is a V/Q scan ordered for
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to R/O PE, evaluate COPD and emphysema
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What is done in V/Q tests
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Patient breaths in Aerosol Isotope for Vent Images Isotope is then injected for Perfusion Imgaes
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What should be seen in a V/Q scan
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no mismatch of perfusion defects no air trapping, even flow of air
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What are renal scans indicated for (5 things)
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Show Renal function Detect and Localize Renal Masses Evaluate Acute and Chronic Pyelonephritis Evaluate for Renal Blood flow obstruction ->>Renal artery stenosis Evaluate Renal Transplants --->Both donor and recipient
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How does a Renal scan work?
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Injection of Isotope that is a waste product -->>Body sees it as useless and wants to get rid of it Filtered by Kidney and excreted with urine
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For a renal scan, how much of the isotope should be in the kidney within an hour
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50%
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What should you see on a renal scan
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As you get lower the bladder shows up and kidneys disappear --- both kidneys at the same time -- equal flow
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what can asymmetry represent on renal scan
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decrease function, renal artery stenosis, hydroureteronephosis
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What is a HIDA scan used to see
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Hepatobiliary or Gallbladder scan
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Why would you order a HIDA scan
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to show GB function, surgical leaks, cholecyctitis, evaluation of liver transplant
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What is the isotope in HIDA tests similar to?
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similar to bile; Polygonal cell uptake in Liver and then follows bile pathway
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What is evaluated in a HIDA scan
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Evaluate timing of liver activity, GB activity, small bowel to check bile flow Can inject CCK which causes GB to contract --->Measure GB injection fraction to asses function
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In what time frames should organs appear on HIDA scan
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Liver 5-15 minutes Hepatic Duct, Common bile Duct, and GB in 5-20 minutes Intestinal Activity 10-60 minutes
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What is abnormal in a HIDA scan
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Nonvisualization of GB by 60 minutes --> Cystic duct obstruction, acute cholecystitis (infection or inflammation) Nonvisualization of bowel by 60 minutes --> Sphincter of Oddi dysfunction or obstruction
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Post surgical HIDA scan abnormality
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Pooling near anatomical location of absent GB indicates leak ---> Bad RUQ pain - bile pools in an area where something wasn't stitched right and sits in GB cavity
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Number 1 reason for HIDA scan
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acute cholecytitis
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What is used in thyroid uptake scans
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ingest radioactive iodine
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why order a thyroid uptake scan?
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Hyper/Hypo Thyroid Evaluate nodules, cancer or benign Localize ectopic thyroid tissue
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"Spots" on thyroid scans vs other scans
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a cold spot is cancer .. Bright = hot = hyperthyroid Bone scan hot spot = cancer
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enlarged thyroid with mottled appearance
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Hashimotos Thyroiditis
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enlarged gland with high uptake
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graves
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Nonvisualization of thyroid
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Subacute Thyroiditis
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what is a 131 total body scan used for
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Treatment for Thyroid Cancer Higher Dose Beta ray kills residual Tissue
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what does a 131 TBS show
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Normal uptake in GI Tract and salivary glands, and thyroid Abnormal uptake in right lung and chest
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What is a bleeding scan used for
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To locate and asses GI Bleeds
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What does a bleeding scan inject
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Injection of Tagged RBCs followed images Abnormal Results will show pooling in abdominal cavity Making RBC radioactive like MUGA - look for blood pooling
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what is hard about a bleeding scan
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Hard part is person must be actively bleeding, waxing and waning can make it hard. Must be bleeding while under the camera
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What is injected in a lymphoscintigraphy
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Injection of Tc-Tin Colloid Shows Lymphatic flow pre operative
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PET scan
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Positron Emission Tomography
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how does a pet scan work
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Isotope localization by cellular metabolism' Cancer requires more energy, thus more isotope localizes in tumor Mainly used for Cancer staging, response to treatment, and tumor localization
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Riglers Sign
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Visualization of both sides of bowel wall in presnce of pneumoperitoneum - air everywhere due to backed up stool
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Lemon Sign
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build up of pleural fluid in between lung fissures- some call them pseudotumors - common in CHF
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Silhouette Sign
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two objects of the same radiographic density touch each other so the edge or margin bw them disappears
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pedicle sign
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destruction of vertebral pedicle (seen more with metastatic)
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Coffee Bean sign
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dilated sigmoid colon in sigmoid volvulus
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Continuous Diaphragm Sign
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visualization of the entire upper surface of the diaphragm from pneumomediastinum
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Deep sulcus sign
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indicates presence of a pneumothorax - air collects anteriorly and basally of the pleural space when the patient is in the supine position
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water bottle sign
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in a pericardial effusion, too much fluid builds up around the heart in the pericardial cavity
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Kerley B Lines
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short 1-2 cm horizontal lines near costophrenic angles
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white out of the lung
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atelectasis, pleural effusion, pneumonia, cancer, pneumonectomy, mucus plug obstruction, foreign body obstruction
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cause shift toward white out
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cancer, mucus plug obstruction, foreign body obstruction
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shift away from white out
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pleural effusion
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pneumobilia
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presence of gas in the biliary system
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Retroperitoneal Air
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gas or air within the retroperitoneal space - air outlines the kidneys, psoas muscles, bowel portion
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ring like calcifications
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implies calcification that has occurred in the wall of a hollow viscus/organ - (cysts, aneurysms, gallbladder, urinary bladder)
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Sternum pushed back
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pectus excavatum
