Optimizing PSMA scintigraphy for resource limited settings - a retrospective comparative study

Area of Science:

• Nuclear medicine
• Oncology
• Medical imaging

Background:

• Prostate cancer (PCa) management relies on sensitive imaging, but PET/CT is often inaccessible in developing regions.
• Technetium-99m-labeled PSMA scintigraphy (PS) offers a more accessible alternative using gamma cameras.
• Resource constraints may necessitate simplified PS protocols, such as limited field of view (FOV) or omitting SPECT/CT.

Purpose of the Study:

• To evaluate the adequacy of simplified [99mTc]Tc-PSMA scintigraphy (PS) protocols for prostate cancer (PCa) detection and staging.
• To determine if planar-only or SPECT-only imaging with a limited FOV is sufficient in resource-limited settings.

Main Methods:

• Retrospective review of PS scans from 95 histologically confirmed PCa patients.
• Comparison of detection rates for primary tumor and metastases across planar, SPECT, and SPECT/CT imaging.
• Assessment of inter-modality agreement for metastasis detection and TNM staging.
• Evaluation of the impact of a limited FOV on imaging findings.

Main Results:

• SPECT/CT detected pathological prostatic uptake in all evaluable cases; SPECT showed 90.3%, and planar images 15.1%.
• Seminal vesicle involvement was identified on SPECT/CT but not on planar or SPECT alone in 11.7% of patients.
• Agreement was moderate to good for nodal metastases (κ=0.41–0.61) and good for bone metastases (κ=0.73–0.77).
• TNM staging agreement was good (κ=0.70–0.88), and no metastatic lesions were missed with a limited FOV.

Conclusions:

• While SPECT/CT is recommended for [99mTc]Tc-PSMA scintigraphy (PS), planar and SPECT imaging are adequate for staging most prostate cancer (PCa) patients in resource-limited environments.
• Simplified PS protocols, including limited FOV, can optimize imaging time without compromising staging accuracy.
• The accessibility of PS makes it a valuable tool for PCa management where advanced imaging is unavailable.