99mTc-Succimer is a radiopharmaceutical agent used for high-resolution imaging of the renal cortex. It is composed of succimer, a chelating agent that binds to technetium-99m (99mTc), a radioactive isotope. When injected into the bloodstream, 99mTc-Succimer is rapidly taken up by the kidneys and selectively accumulates in the renal cortex, allowing for clear and precise imaging of this area.
The use of 99mTc-Succimer in renal imaging is particularly valuable in the diagnosis and monitoring of various kidney diseases, including renal artery stenosis, renal vascular disorders, and renal scarring. By providing detailed images of the renal cortex, this radiopharmaceutical can help clinicians accurately assess the structure and function of the kidneys, identify abnormalities, and guide treatment decisions.
Overall, 99mTc-Succimer plays a crucial role in high-resolution imaging of the renal cortex, offering clinicians a powerful tool for diagnosing and managing a wide range of kidney conditions.
Description
99mTc-Succimer (99mTc-DMSA, 99mTc-meso-2,3-dimercaptosuccinic acid) is a generic SPECT tracer for the evaluation of renal parenchymal disorders.
Clinical applications
DMSA is used for high-resolution imaging of the renal cortex. The agent is slowly cleared from the blood as a result of its high protein binding in proximal renal tubules. Peak renal activity is seen 4 to 6 hours post injection, but images are usually acquired before this time. This agent is used for renal scintigraphic examination, determination of functional renal mass and individual kidney function.
DMSA as an alkaline preparation (different kit) can also be used to image tumors (diagnosis of head and neck tumors, medullary carcinoma of thyroid and soft tissue tumors). The interest in this application is declining since FDG is available, but still used in areas without access to 18F and PET cameras.
Typical doses are between 1 and 5 mCi and the critical organ is the kidney. In 2020 in the USA, a dose of 99mTc-Succimer is charged around US$ 700.
Availability
99mTc-DMSA is a generic product (first MAs around 1982) sold under the brand names DMSA and DMSA(V) (Pars Isotope), Mercapton (Medi-Radiopharma), MON-DMSA (Monrol), Penta-DMSA (Medi-Radiopharma), PoltechDMSA (POLATOM), Renocis (IBA Molecular (Curium); marketed since 1986), ROTOP-DMSA (ROTOP), TCK-33 (BRIT), Techne® DMSA (Fuji Film), Technemek (DiaMed, Russian MA 1989), Technescan DMSA (Mallinckrodt).
The supply of MPI-DMSA from GE Healthcare is suspended since 2014.
Due to the current (2019) critical shortage in the USA of DMSA Kit for the preparation of 99mTc-Succimer, Theragnostics has initiated temporary importation of the ROTOP-DMSA kit under the name 99mTc-THG-002. Theragnostics has appointed Medi-Physics Inc. (GEH), as the U.S. distributor. Theragnostics was granted a temporary importation allowance by the FDA.
Competition
99mTc-DMSA is one of the most common tracers, which explains the high number of companies offering this generic. It is part of the standard list of products used daily in nuclear medicine and the competition is mainly between brands, mainly affecting the prices.
Comments
99mTc-DMSA is an older product that has proven to be efficient over the years and will be displaced by new tracers only in some specific niche indications, making it of relatively low interest for newcomers who will have to compete with an established low-cost generic.