Radiopharmaceuticals for single-photon emission computed tomography brain imaging

Area of Science:

• Neuroscience
• Radiochemistry
• Medical Imaging

Background:

• Significant advancements in brain-imaging agents for single-photon emission computed tomography (SPECT) have occurred over the last decade.
• Most novel radiopharmaceuticals target specific neurotransmitter receptor or transporter sites within the central nervous system.
• Iodine-123 (123I) is the predominant radioisotope used for labeling site-specific brain radiopharmaceuticals.

Purpose of the Study:

• To review the progress and applications of new brain-imaging agents for SPECT.
• To highlight the diagnostic utility of radiopharmaceuticals targeting neurotransmitter systems.
• To discuss the potential of technetium-99m (99mTc) labeled agents for broader clinical adoption.

Main Methods:

• Review of radiopharmaceuticals developed for SPECT brain imaging.
• Focus on agents labeled with 123I and 99mTc.
• Discussion of clinical applications in neurological and psychiatric disorders.

Main Results:

• 123I-labeled agents like [(123)I]iomazenil are useful for imaging gamma-aminobutyric acid receptors, aiding epilepsy diagnosis and understanding psychiatric conditions.
• 123I-labeled agents for dopamine D2/D3 receptors and transporters facilitate the differential diagnosis of Parkinson's disease and other neurodegenerative disorders.
• A 99mTc-labeled agent, [(99m)Tc]TRODAT, has shown success in imaging dopamine transporters for Parkinson's disease diagnosis.

Conclusions:

• Clinical use of 123I-labeled brain radiopharmaceuticals in the US is limited by supply challenges, despite their efficacy.
• The development of 99mTc-labeled agents is expected to expand the routine application of site-specific brain radiopharmaceuticals.
• These advancements will aid in the diagnosis and treatment monitoring of diverse neurologic and psychiatric conditions.