This is an old revision of this page, as edited by DAnuu(talk | contribs) at 21:25, 29 June 2020(→Technetium-99m: Changed link from "technetium" article to "technetium-99m" specific article. The previous phrase, "Technetium-99 is a gamma emitter" is not true (Tc-99 decays by beta emission), but "Technetium-99m is a gamma emitter" is true. Removed link to "technetium-99m" in the sentence that follows to avoid repetition.). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 21:25, 29 June 2020 by DAnuu(talk | contribs)(→Technetium-99m: Changed link from "technetium" article to "technetium-99m" specific article. The previous phrase, "Technetium-99 is a gamma emitter" is not true (Tc-99 decays by beta emission), but "Technetium-99m is a gamma emitter" is true. Removed link to "technetium-99m" in the sentence that follows to avoid repetition.)
Radiopharmaceuticals, or medicinal radiocompounds, are a group of pharmaceutical drugs containing radioactive isotopes. Radiopharmaceuticals can be used as diagnostic and therapeutic agents. Radiopharmaceuticals emit radiation themselves, which is different from contrast media which absorb or alter external electromagnetism or ultrasound. Radiopharmacology is the branch of pharmacology that specializes in these agents.
The main group of these compounds are the radiotracers used to diagnose dysfunction in body tissues. While not all medical isotopes are radioactive, radiopharmaceuticals are the oldest and still most common such drugs.
A list of nuclear medicine radiopharmaceuticals follows. Some radioisotopes are used in ionic or inert form without attachment to a pharmaceutical; these are also included. There is a section for each radioisotope with a table of radiopharmaceuticals using that radioisotope. The sections are ordered alphabetically by the English name of the radioisotope. Sections for the same element are then ordered by atomic mass number.
18F is a positron emitter with a half-life of 109 minutes. It is produced in medical cyclotrons, usually from oxygen-18, and then chemically attached to a pharmaceutical. See PET scan.
125I is a gamma emitter with a long half-life of 59.4 days (the longest of all radioiodines used in medicine). Iodine-123 is preferred for imaging, so I-125 is used diagnostically only when the test requires a longer period to prepare the radiopharmaceutical and trace it, such as a fibrinogen scan to diagnose clotting. I-125's gamma radiation is of medium penetration, making it more useful as a therapeutic isotope for brachytherapy implant of radioisotope capsules for local treatment of cancers.
Name
Investigation
Route of administration
In-vitro / in-vivo
Imaging / non-imaging
I125-fibrinogen
Clot imaging
IV
In-vivo
Imaging
Iodine-131
131I is a beta and gamma emitter. It is used both to destroy thyroid and thyroid cancer tissues (via beta radiation, which is short-range), and also other neuroendocrine tissues when used in MIBG. It can also be seen by a gamma camera, and can serve as a diagnostic imaging tracer, when treatment is also being attempted at the same time. However iodine-123 is usually preferred when only imaging is desired.
Technetium-99m is a gamma emitter. It is obtained on-site at the imaging center as the soluble pertechnetate which is eluted from a technetium-99m generator, and then either used directly as this soluble salt, or else used to synthesize a number of technetium-99m-based radiopharmaceuticals.