Trans-1-amino-3-[(18)F]fluorocyclobutanecarboxylic acid (also known as Fluciclovine (18F)) was approved under brand name AXUMIN as a radioactive diagnostic agent indicated for positron emission tomography (PET) imaging in men with suspected prostate cancer recurrence. Besides, this radioactive compound is used in patients with cervical, ovarian epithelial or endometrial cancers. Fluciclovine F 18 is a synthetic amino acid transported across mammalian cell membranes by amino acid transporters, such as LAT-1 and ASCT2, which are upregulated in prostate cancer cells, but as was shown, this compound has a higher affinity for ASCT2 in comparison with other transporters.

SULFUR HEXAFLUORIDE is a component of LUMASON® (sulfur hexafluoride lipid-type A microspheres). It is an ultrasound contrast agent indicated for use in the heart echocardiography and in ultrasonography of the liver and the urinary tract. The sulfur hexafluoride lipid microspheres are composed of SF6 gas in the core surrounded by an outer shell monolayer of phospholipids with palmitic acid as a stabilizer.

Perflutren is a diagnostic drug that is used for the contrast enhancement during echocardiographic. It consists of lipid-coated microspheres filled with octafluoropropane gas. Ultrasound waves make the microspheres resonate and reflect a strong signal to an ultrasound machine. This results in a difference of density between gas-filled bubbles and blood around them and improves contrast of resulting images. Perflutren is used in patients with suboptimal echocardiograms to opacify the left ventricular chamber and improve the delineation of the heart borders.

Urea C-14 is a urea molecule radiolabelled with a radioactive carbon-14. Urea C-14 Breath Test is indicated for use in the detection of gastric urease as an aid in the diagnosis of H.pylori infection in the human stomach. The test utilizes a liquid scintillation counter for the measurement of CO in breath samples. To detect H.pylori, urea labeled with C is swallowed by the patient. If gastric urease from H.pylori is present, urea is split to form CO and NH at the interface between the gastric epithelium and lumen and CO is absorbed into the blood and exhaled in the breath. Antibiotics, proton pump inhibitors, sucralfate, and bismuth preparations are known to suppress H.pylori. Ingestion of antibiotics or bismuth within 4 weeks and proton pump inhibitors or sucralfate within 2 weeks prior to performing the test may give false negative results.

Iodixanol (brand name VISIPAQUE) is an iodine-containing nonionic dimeric hydrophilic contrast agent for intravascular (intravenous and intra-arterial) use during coronary angiography. Pharmacodynamics studies indicated that iodixanol had fewer cardiovascular effects, caused less renal damage and were associated with similar or smaller changes to the blood-brain barrier and neurological function when compared with nonionic contrast media. It is known, that the organic iodine compounds attenuate x-rays as they pass through the body, thereby allowing the body structures containing iodine to be delineated in contrast to those structures that do not contain iodine. The degree of opacity produced by these compounds is directly proportional to the total amount (concentration and volume) of the iodinated contrast agent in the path of the x-rays. Thus, after intravascular administration, iodixanol makes opaque those internal structures in its path of flow, allowing their visualization until significant hemodilution and elimination occur.

Urea 13C is a urea molecule radiolabelled with the non-radioactive element carbon-13. 13C-urea present in drugs which are intended for use in the qualitative detection of 13CO2 in whole blood specimens, collected after the ingestion of 13C-urea. Helicobacter pylori (H. pylori) organisms colonizing the lining of the human stomach, produce urease which converts 13C-urea into 13CO2 and ammonia (NH4+). In the presence of urease associated with gastric H. pylori, 13C-urea is decomposed to 13CO2 and ammonia NH4. The 13CO2 is absorbed in the blood, then exhaled in the breath. This results in an increase in the ratio of 13CO2 to 12CO2 in a TEST breath sample compared to a BASELINE sample.

Iopromide is a molecule used as a contrast medium. It is a low osmolar, non-ionic contrast agent for intravascular use. It is commonly used in radiographic studies such as intravenous urograms, brain computer tomography (CT) and CT pulmonary angiograms (CTPAs). It appears to increase the risk of biguanide induced lactic acidosis. Interleukins are associated with an increased prevalence of delayed hypersensitivity reactions after iodinated contrast agent administration. Most common adverse reactions (>1%) are headache, nausea, injection site and infusion site reactions, vasodilatation, vomiting, back pain, urinary urgency, chest pain, pain, dysgeusia, and abnormal vision.

Gadodiamide is a nonionic, low-osmolar gadolinium-based contrast agent for diagnostic contrast-enhanced magnetic resonance imaging (MRI).

Gadoteridol (INN) is a gadolinium-based MRI contrast agent, used particularly in the imaging of the central nervous system. It is sold under the brand name ProHance. Gadoteridol is a paramagnetic agent and, as such, develops a magnetic moment when placed in a magnetic field. The relatively large magnetic moment produced by the paramagnetic agent results in a relatively large local magnetic field, which can enhance the relaxation rates of water protons in the vicinity of the paramagnetic agent. In magnetic resonance imaging (MRI), visualization of normal and pathologic brain tissue depends in part on variations in the radiofrequency signal intensity that occur with 1) differences in proton density; 2) differences of the spin-lattice or longitudinal relaxation times (T1); and 3) differences in the spin-spin or transverse relaxation time (T2). When placed in a magnetic field, gadoteridol decreases T1 relaxation times in the target tissues. At recommended doses, the effect is observed with greatest sensitivity in the T1-weighted sequences. Gadoteridol does not cross the intact blood-brain barrier and, therefore, does not accumulate in normal brain or in lesions that have a normal blood-brain barrier, e.g., cysts, mature post-operative scars, etc. However, disruption of the blood-brain barrier or abnormal vascularity allows accumulation of gadoteridol in lesions such as neoplasms, abscesses, and subacute infarcts. The pharmacokinetics of ProHance in various lesions is not known.

Ioversol is an organoiodine compound that used as a contrast medium. It features both a high iodine content, as well as several hydrophilic groups. It is indicated in adults for peripheral and coronary arteriography and left ventriculography, for excretory urography and computed tomography. Injections of contrast media are often associated with sensations of warmth and pain. Renal toxicity has been reported in a few patients with liver dysfunction who were given oral cholecystographic agents followed by intravascular contrast agents.