thallium (redirected from Tallium)

thallium /thal·li·um/ (thal´e-um) chemical element, at. no. 81, symbol Tl. It may be absorbed from the gut and from the intact skin, causing a variety of neurologic and psychic symptoms and liver and kidney damage.

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thallium 201  a radioactive isotope of thallium having a half-life of 3.05 days and decaying by electron capture with emission of gamma rays (0.135, 0.167 MeV); it is used as a diagnostic aid in the form of thallous chloride Tl 201.

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thal·li·um (thl-m)

n. Symbol Tl

A soft, malleable, highly toxic metallic element whose radioisotopes are used in diagnostic imaging. Atomic number 81.

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thallium

a chemical element, atomic number 81, atomic weight 204.37, symbol Tl. See Table 6. Its salts are active poisons. See thallotoxicosis.

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thallium-201

a radioactive isotope of thallium having a half-life of 73.5 hours; the principal emission is 71 keV x-rays.

thallium poisoning

see thallotoxicosis.

thallium scan

a scintillation scan involving the use of thallium-201 which localizes in the myocardium after intravenous injection. Areas of inadequate perfusion pinpoint the site of coronary artery occlusions.