Thallous Chloride Tl 201 Injection is indicated for use with planar scintigraphy or single-photon emission computed tomography for the following applications: Myocardial perfusion imaging in adults for the diagnosis of coronary artery disease by localization of: Non-reversible defects Reversible defects when used in conjunction with exercise or pharmacologic stress Localization of sites of parathyroid hyperactivity pre- and post-operatively in adults with elevated serum calcium and parathyroid hormone levels Thallous Chloride Tl 201 Injection is a radioactive diagnostic drug indicated for use with planar scintigraphy or single-photon emission computed tomography for: Myocardial perfusion imaging in adults for the diagnosis of coronary artery disease by localization of: Non-reversible defects Reversible defects when used in conjunction with exercise or pharmacologic stress Localization of sites of parathyroid hyperactivity pre- and post-operatively in adults with elevated serum calcium and parathyroid hormone levels