Technique
The main technique uses scintigraphy to produce two-dimensional images. After the tracer has been injected, images are taken by a gamma camera at 24, 48, and in some cases, 72, and 96 hours later. Each set of images takes 30–60 minutes, depending on the size of the area being imaged. The resulting image will have bright areas that collected large amounts of tracer, because inflammation is present or rapid cell division is occurring. Single photon emission computed tomography (SPECT) images may also be acquired. In some imaging centers, SPECT images may be combined with computed tomography scan using either fusion software or SPECT/CT hybrid cameras to superimpose both physiological image-information from the gallium scan, and anatomical information from the CT scan.
Radiochemistry:
Gallium-67 citrate is produced by a cyclotron. Charged particle bombardment of enriched Zn-68 is used to produce gallium-67. The gallium-67 is then complexed with citric acid to form gallium citrate. The half life of gallium-67 is 78 hours. It decays by electron capture. The target organ is large bowel.
Gallium-67 photopeaks: Energy Abundance 93 keV 40% 184 keV 20% 300 keV 17% 393 keV 5%
10% to 25% of the dose of gallium-67 is excreted within 24 hours after injection (the majority of which is excreted through the kidneys). After 24 hours the principal excretory pathway is colon.
Areas where Ga-67 normally localizes include: liver (site of highest uptake) bone marrow spleen salivary glands nasopharynx lacrimal glands breast uptake (especially in pregnant and lactating women) kidneys and bladder in the first 24 hours - faint uptake can still be normal for up to 72 hours mild diffuse lung uptake at 24 hours or less
Tissue distributions in children which differ from those in adults: growth plates spleen thymus
Common injection doses range from 3-6 mCi. Imaging should not usually be sooner than 24 hours - high background at this time produces false negatives. Forty-eight hour whole body images are appropriate. Delayed imaging can be obtained even 1 week or longer after injection if bowel is confounding. SPECT can be performed as needed. Oral laxatives or enemas can be given before imaging to reduce bowel activity and reduce dose to large bowel; however, the usefulness of bowel preparation is controversial.
Read more about this topic: Gallium 67 Scan
Famous quotes containing the word technique:
“The mere mechanical technique of acting can be taught, but the spirit that is to give life to lifeless forms must be born in a man. No dramatic college can teach its pupils to think or to feel. It is Nature who makes our artists for us, though it may be Art who taught them their right mode of expression.”
—Oscar Wilde (1854–1900)
“The more technique you have, the less you have to worry about it. The more technique there is, the less there is.”
—Pablo Picasso (1881–1973)
“The audience is the most revered member of the theater. Without an audience there is no theater. Every technique learned by the actor, every curtain, every flat on the stage, every careful analysis by the director, every coordinated scene, is for the enjoyment of the audience. They are our guests, our evaluators, and the last spoke in the wheel which can then begin to roll. They make the performance meaningful.”
—Viola Spolin (b. 1911)