Tumor detection with carbon-11-labelled amino acids

Area of Science:

• Biomedical imaging
• Radiochemistry
• Oncology

Background:

• Positron emission tomography (PET) is a crucial imaging technique in oncology.
• Developing novel radiotracers, specifically carbon-11 labeled amino acids, can enhance tumor detection and characterization.
• Amino acid metabolism is often altered in cancerous tissues, making labeled amino acids promising diagnostic agents.

Purpose of the Study:

• To comparatively evaluate ten different carbon-11 (11C) labeled amino acids for their efficacy in tumor detection.
• To identify the most suitable 11C-labeled amino acid for diagnosing cancer using PET.
• To assess the tumor uptake and biodistribution of newly synthesized amino acids.

Main Methods:

• A comparative study involving ten 11C-labeled amino acids, including four novel compounds.
• In vivo evaluation of tumor detection in experimental rat hepatoma AH109A models.
• Quantification of radiotracer uptake in tumors, blood, and liver, along with calculation of tumor-to-blood and tumor-to-liver ratios at various time points post-injection.

Main Results:

• 11C-L-methionine exhibited the highest tumor uptake (2.7% administered dose/g at 20 min) and the best tumor-to-blood ratio (11.4).
• 11C-aminocyclopentane-carboxylic acid (ACPC) showed the second-highest uptake.
• The novel tracer 11C-DL-methyl-ACPC demonstrated significant accumulation in tumors compared to the liver, with a tumor-to-liver ratio of 3.0 at 60 min.

Conclusions:

• 11C-L-methionine is a highly effective 11C-labeled amino acid for cancer diagnosis via PET imaging.
• 11C-DL-methyl-ACPC also shows potential as a useful radiotracer for cancer diagnosis due to its selective tumor accumulation.
• These findings support the use of specific 11C-labeled amino acids for improved PET-based cancer detection.