Items tagged “nuclear medicine”
49 results found
Article
Superscan
A superscan is an imaging appearance on a Tc-99m diphosphonate bone scan which occurs as a result of a high ratio of bone to soft tissue tracer accumulation. Intense osteoblastic activity in the bones causes diminished renal and background soft tissue uptake.
Pathology
Etiology
This appearanc...
Article
Pelviureteric junction obstruction
Pelviureteric junction (PUJ) obstruction/stenosis, also known as ureteropelvic junction (UPJ) obstruction/stenosis, can be one of the causes of obstructive uropathy. It can be congenital or acquired with a congenital pelviureteric junction obstruction being one of the commonest causes of antenat...
Article
Graves disease
Graves disease, also known as Basedow disease in mainland Europe 9, is an autoimmune thyroid disease and is the most common cause of hyperthyroidism.
Epidemiology
There is a strong female predilection (F:M = 5:1), and is most common between 30-60 years 14. The incidence is 20 per 100,000 peopl...
Article
Technetium-99m agents
Technetium agents based on the technetium-99m (Tc-99m) radioisotope are frequently used agents in medical imaging. A radiopharmaceutical labeled with Tc-99m constitutes a co-ordination complex in which ligands bond to a central atom of Tc-99m by co-ordinate covalent bonds 4 .
The radioactive te...
Article
Radiopharmaceuticals
Radiopharmaceuticals are drugs that are bound to radioactive substances. They may be used for diagnostic imaging, as therapeutic agents, or both (theranostic).
The most commonly used radionuclide is Technetium-99m. In some cases, such as Iodine-123, the radioactive molecule itself has a physiol...
Article
Tc-99m sulfur colloid
Technetium-99m sulfur colloid is one of the technetium radiopharmaceuticals.
Characteristics
photon energy: 140 keV
physical half-life: 6 hours
biological half-life: 2 to 3 minutes
normal distribution:
liver: 85%
spleen: 10%
bone marrow: 5%
excretion: hepatic
target organ: liver, splee...
Article
Xenon-133
Xenon-133 is a radiopharmaceutical principally used when a performing VQ scan. Inhalation of this gas can also be used to assess cerebral blood flow.
Mode of decay: Beta decay
photon energy: 81 KeV
physical half-life: 5.27 days
biological half-life: 30 seconds
normal distribution: lungs
<1...
Article
Iodine-123
Iodine-123 (I123 or I-123) is a radioisotope of the element iodine (atomic number 53) used in nuclear medicine imaging including to scan the thyroid gland.
Uses, dosages, and time of Imaging
standard scan: 3.7-14.8 MBq (100-400 μCi) PO, image at 4-6 or 24 hours
thyroid cancer scan: 55.5 MBq ...
Article
Thyroid scintigraphy (I-123)
Thyroid scintigraphy (thyroid scan) is a nuclear medicine examination used to evaluate thyroid tissue.
Clinical indications
functional status of a thyroid nodule
thyrotoxicosis: differential diagnosis
thyroid cancer
whole body scan for distant metastases
estimation of local residual thyro...
Article
Tc-99m DMSA
Tc-99m DMSA (2,3 dimercaptosuccinic acid) is a technetium radiopharmaceutical used in renal imaging to evaluate renal structure and morphology, particularly in pediatric imaging for detection of scarring and pyelonephritis. DMSA is an ideal agent for assessment of the renal cortex as it binds to...
Article
Tc-99m DTPA
Tc-99m DTPA (diethylene-triamine-pentaacetate) is one of the technetium radiopharmaceuticals used in renal imaging and primarily used to measure the glomerular filtration rate (GFR).
Characteristics
photon energy: 140 KeV
physical half-life: 6 hours
oxidation state of technetium: +4
biologi...
Article
PET-CT indications
PET-CT is a combination of cross-sectional anatomic information provided by CT and the metabolic information provided by positron emission tomography (PET).
PET is most commonly performed with 2-[F-18]fluoro-2-deoxy-D-glucose (FDG). Fluorine-18 (F-18) is an unstable radioisotope and has a half-...
Article
Tc-99m MAG3
Tc-99m MAG3 (mercaptoacetyltriglycine) is one of the technetium radiopharmaceuticals used in renal imaging. Due to favorable energy and dosimetric characteristics, MAG3 radiolabeled with technetium has replaced the iodide-131 Hippuran for the study of renal function (tubular secretion physiology...
Article
Tc-99m pertechnetate
Tc-99m pertechnetate (Na+ 99mTc O4-) is one of the technetium radiopharmaceuticals used in imaging of thyroid, colon, bladder and stomach.
Technetium (99mTc) has eight oxidation states 6, from -1 to +7; specifically, the oxidation state of technetium in the pertechnetate anion (99mTcO4-) is +7....
Article
Thyroid scintigraphy (Tc-99m)
Tc-99m pertechnetate thyroid scintigraphy (thyroid scan) is a functional nuclear medicine study used to assess the thyroid gland. The uptake of the pertechnetate anion - similar in chemical-physical characteristics to the iodide ion (i. e. ionic size and negative charge) - in the thyroid parench...
Article
Tc-99m HMPAO labeled WBC
Tc-99m HMPAO (hexamethylpropyleneamine oxime) labeled WBC is one of the technetium radiopharmaceuticals used in WBC imaging.
There are three potential radiochemical impurities in the 99mTc-HMPAO: a hydrophilic secondary complex, the free pertechnetate and the reduced 99mTc-hydrolyzate. 1The min...
Article
Tc-99m MAA
Tc-99m MAA (macroaggregated albumin) is one of the technetium radiopharmaceuticals used in lung perfusion imaging.
Characteristics
photon energy: 140 KeV
physical half life: 6 hours
biological half life: 2-3 hours
normal distribution: lungs, liver, spleen, kidneys
pharmacokinetics:
>90% p...
Article
Scintigraphy performed with Tc-99m labeled RBCs
Tc-99m labeled RBCs - with radiolabelling technique in vivo or in vitro of red cells 3 - is one of the technetium radiopharmaceuticals used in the non-invasive assessment of gastrointestinal (GI) bleeding 2, characterized by high sensitivity (93%) and specificity (95%) 4. It is capable, in fact,...
Article
Tc-99m sestamibi
Tc-99m sestamibi (sestamibi is a shortening of sesta-methoxyisobutylisonitrile) is one of the technetium radiopharmaceuticals.
Characteristics
photon energy: 140 KeV
physical half-life: 6 hours
lipophilic cation
normal distribution: thyroid, parathyroid, heart (myocardium)
e...
Article
Tc-99m DTPA (aerosol)
Tc-99m DTPA (diethylenetriamine-pentaacetic acid) (aerosol) is one of the technetium agents and is used in VQ imaging.
Characteristics
photon energy: 140 KeV
physical half life: 6 hours
biological half life: 1 hour
normal distribution: lungs
pharmacokinetics:
aerosol deposited in bronhoal...
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