Iofetamine hydrochloride I-123 is a radiopharmaceutical for cerebral perfusion imaging. lofetamine is the N-isopropyl derivative of amphetamine with iodine 123(1123) at the para position to serve as the tracer. This configuration was systematically derived by Winchell et al. to provide sufficient brain uptake and retention for brain imaging, which typically requires an acquisition time of 25-40 minutes. After experimental intraarterial injection the drug has a high extraction ratio (> 90 percent) in the brain. Iofetamine hydrochloride I-123 permits cerebral blood perfusion imaging with single photon emission computed tomography (SPECT). Iofetamine is an amphetamine analog that is rapidly taken up by the lungs, then redistributed principally to the liver and brain. The precise mechanism of localization has not been determined, but is believed to result from nonspecific receptor binding. Brain uptake peaks at 30 minutes postinjection and remains relatively constant through 60 minutes. The drug is metabolized and excreted in the urine, with negligible activity remaining at 48 hours. When compared with CT in stroke patients, visualization may be performed sooner after symptom onset and a larger zone of involvement may be evident with iofetamine. Localization of seizure foci and diagnosis of Alzheimer's disease may also be possible. As CT has revolutionized noninvasive imaging of brain anatomy, SPECT with iofetamine permits routine cerebral blood flow imaging. Iofetamine hydrochloride I-123 under the brand name Spectamine was approved for use in the United States as a diagnostic aid in determining the localization of and in the evaluation of non-lacunar stroke and complex partial seizures, as well as in the early diagnosis of Alzheimer's disease in 1987. However it was discontinued in USA.

Ioxaglate Sodium Meglumine (trade name Hexabrix) is a new low osmolality ionic contrast agent, that used as a diagnostic radiopaque medium. Following intravascular injection, Ioxaglate Sodium Meglumine is rapidly transported through the circulatory system to the kidneys and is excreted unchanged in the urine. The joint spaces as well as the uterus and fallopian tubes may be visualized by the direct injection of the contrast medium into the region to be studied. The usual adult dose for left coronary arteriography is 8 mL (range 2-14 mL) and for right coronary arteriography is 5 mL (range 1-10 mL). The doses may be repeated as necessary Patients may have clinically insignificant ECG changes during the procedure. The following adverse effects have occurred in conjunction with the administration of iodinated intravascular contrast agents for this procedure: hypotension, shock, anginal pain, myocardial infarction, cardiac arrhythmias (bradycardia, ventricular tachycardia, ventricular fibrillation) and cardiac arrest.

I-123 radiolabeled ortho-iodohippurate is commonly employed for evaluating effective renal plasma flow (ERPF) by means of either in vivo scintigraphy and/or plasma clearance curves. It has been used to evaluate renal functioning in patients with obstructive uropathy, vesicorenal reflux, hypertensiion due to renal artery stenosis.

Bentiromide (Chymex) is a diagnostic agent that was approved for the diagnosis of pancreatic exocrine insufficiency. It is given by mouth as a noninvasive test. The amount of p-aminobenzoic acid and its metabolites excreted in the urine is taken as a measure of the chymotrypsin-secreting activity of the pancreas. Headache and gastrointestinal disturbances have been reported in patients taking bentiromide. Bentiromide is not available in the United States or Canada.

XENON XE-127, a radioactive gas, was developed at Brookhaven National Laboratory in 1973 for lung ventilation imaging. It appears to be preferable to xenon-133 because of the higher counting rates, lower patient radiation dose, and longer shelf life. However, its production ceased in 1993 due to various reasons.

CERULETIDE, also known as caerulein, is a specific decapeptide obtained from the skin of Hila caerulea, an Australian amphibian. It is similar in action and composition to the natural gastrointestinal peptide hormone cholecystokinin. It stimulates gastric, biliary, and pancreatic secretion; and certain smooth muscle. In the research setting, CERULETIDE can be used to induce pancreatitis in experimental animal models.

Iodoxamic acid (previously sold under the brand name Cholovue) is an organoiodine compound that was used as a contrast medium. It is intravenous cholecystocholangiographic agent. It features both a high iodine content as well as several hydrophilic groups.

Krypton Kr 81m is radiolabeled noble gas suitable only for inhalation in diagnostic studies. Krypton Kr 81m used for Imaging ventilated regions of the lung, Combined with pulmonary perfusion scintigraphy for diagnosis of pulmonary embolism and other conditions. Krypton Kr 81m diffuses easily, passing through cell membranes and exchanging freely between blood and tissue. It is distributed in the lungs in a manner similar to air, thus representing the regions of the lung that are aerated. The gamma photons of krypton Kr 81m can then be employed to obtain counts per minute per lung or region of the lung, or to display their distribution as a scan.

Iodamide is an ionic monomeric iodinated radiographic contrast medium. It was used in many procedures and may be given intravenously or by other routes, for example by instillation into the bladder or uterus; it has also been used for computed tomography. It is usually given as a 24 to 65% solution of the meglumine salt, or as a mixture of the sodium and meglumine salts; solutions of the sodium salt have also been used. Iodamide is no longer marketed in the US.

Metrizamide is a glucosamine derivative of metrazoic acid, used as a contrast medium for myelography. Metrizamide is no longer marketed in the US.