Quantitative SPECT/CT for Dosimetry of Peptide Receptor Radionuclide Therapy

Area of Science:

• Nuclear Medicine
• Oncology
• Radiochemistry

Background:

• Neuroendocrine tumors (NETs) are uncommon but increasing malignancies.
• Somatostatin receptor (SSTR) targeted imaging (e.g., ⁶⁸Ga-DOTA-peptides) aids in NET diagnosis and patient selection for therapy.
• Peptide receptor radionuclide therapy (PRRT) using agents like ¹⁷⁷Lu-DOTATATE is a key treatment for metastatic or inoperable NETs.

Purpose of the Study:

• To highlight the limitations of fixed-activity PRRT dosing in NETs.
• To introduce the potential of SPECT imaging for quantitative radiopharmaceutical dosimetry in PRRT.
• To advocate for personalized PRRT based on patient-specific dosimetry to enhance efficacy and safety.

Main Methods:

• Utilizing advances in single photon emission computed tomography (SPECT) for absolute quantitative imaging.
• Measuring true radiopharmaceutical distribution in patients undergoing PRRT.
• Developing patient-specific dosimetry for PRRT treatment planning.

Main Results:

• Fixed PRRT activity may be suboptimal due to variable radiopharmaceutical uptake.
• SPECT imaging enables precise quantification of radiopharmaceutical biodistribution.
• Patient-specific dosimetry can be achieved through quantitative SPECT.

Conclusions:

• Personalized PRRT, guided by SPECT-based dosimetry, offers a more effective treatment strategy for NETs.
• Optimizing absorbed tumor dose while minimizing toxicity to critical organs is achievable.
• Quantitative SPECT imaging is crucial for advancing personalized PRRT in neuroendocrine oncology.