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19 Cards in this Set
- Front
- Back
- 3rd side (hint)
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How is it we can image bone marrow?
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They contain reticuloendothelial cells similar to those found in liver and spleen so we can image with a colloid (sulfur or albumn)
what is the adult dose? |
15 mCi
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What is the particle size for bone marrow?
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<100nm, larger than 100 it will be trapped in the lungs, less than 100 most will trapped in the liver and spleen with about 5% in the bone marrow, this can be increased to 15% with a size of 30 nm (human serum albumin (HSA)
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What is the indication for a bone marrow scan?
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anemia, polycythemia and bone marrow metastasis
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RP and dose for liver/spleen?
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Tc99m sulfur colloid or albumin colloid
3-5 mCi how is it localized? |
phagocytized by the Kupffer cells in liver,spleen and bone marrow
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How can we image the spleen by itself?
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by using the process of denaturing, damaging RBC's by heating them to 50 deg C for 20 min. the spleen removes them by a process called?
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sequestration
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What is the RP and dose for hepatobilary imaging?
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Tc99m IDA agents, lidofenin, hepatolite, choletec or iprofenin
3-5 mCi What is IDA? |
iminodiacetic acid
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How are the IDA derivatives localized to show bile ducts, gallbladder and intestines?
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taken up by hepatocyte cells via active transport
what patient condition decreases this uptake? |
increased bilirubin levels
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What is bilirubin?
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a byproduct of the breakdown of hemoglobin which comes from red blood cells. These byproducts are carried by albumin in the bloodstream to the liver. Bilirubin is then excreted in bile. It is the substance which causes pigmentation of bile.
Used as an indication of liver function and gallbladder function. |
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Patient prep for a HIDA scan?
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NPO for at least 2 hrs prior to test but not prolonged fasting and no opiates 2-6 hrs prior
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What is CCK for hepatobilary imaging for?
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Cholecystokinin (CCK) is a hormone excreted by the duodenal mucosa. Its function is to cause the gallbladder to contract and the sphincter of Oddi to relax. CCK is used to distinguish between acute and chronic cholecystitis and to assist in the calculation of the gallbladder ejection fraction. A patient with complete obstruction of the cystic duct, acute cholecystitis, will not have visualization of the gallbladder after administration of CCK. A patient with partial obstruction of the gallbladder, chronic cholecystitis, should have visualization of the gallbladder after CCK.
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How is a gallbladder ejection fraction done and what is normal?
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administration of CCK with ROI drawn before and after administration
less than 35% indicated abnormalities in function |
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Indications for HIDA?
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Acute or chronic cholecystitis
Calculation of gallbladder ejection fraction Evaluation of enterogastric reflux (bile reflux) Jaundice (obstructive vs. non-obstructive) Evaluation of cold defects on liver scan. Primary sclerosing cholangiitis (bile duct damage and blockage) |
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What is the RP for GI bleed and how is it localized?
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Tc99m labeled RBC or SC
Compartmental Indications? |
Suspected lower GI bleeding, blood in stool
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Explain basic RBC labeling
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A stannous compound is mixed with blood. The Sn2+ ion enters the RBC. TcO4- then is added diffused into the cell, is reduced by the Sn2+, and then binds to hemoglobin within the cell.
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What is the RP and dose for Meckel's Diverticulum?
how is it localized? |
99mTcO4, adult dose 15mCi
localized by absorption by gastric mucosa through active transport what are the indications? |
GI bleeding in children and young adults
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Explain the process for gastric emptying imaging?
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99mTcO4 or SC (300uCi) cooked in eggs, makes Tc labeled egg albumin.
localized by compartmentalization. a solid 300 cal meal -63% empties in 1 hr Indications? |
suspected delay in gastric emptying and evaluation of therapy in known cases of delayed gastric emptying
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How is the esophagus imaged?
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Imaging of the esophogus performed while patient is supine. Stomach is positioned at the bottom of the field of view. The patient must fast for 2 hrs prior to the study.
Patient is given 300 uCi in 15 ml water and instructed to swallow the entire mouthful at once. The patient then dry swallows once every 15 secs for 10 mins. |
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How is gastric reflux imaging accomplished?
method of localization? |
Adults - Approx. 300 Ci of 99mTc sulfur colloid in acidified orange juice .Orange juice is acidified with of 150 ml of 0.1 N HCl,
Children – 150 Ci to 1 mCi of 99mTc sulfur colloid added to milk or Formula. Sometimes referred to as a “Milk Scan”. Localization: compartmentalization Indications? |
adults: chest pain and regurgitation, evaluation of surgery or therapy in known cases
Children: possible reflux, recurrent pneumonia |
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What is Clark's formula for calculating pediatric dose?
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Child’s Dose = (childs weight) ( adult dose)/150 lb
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