Nuclear Medicine & Radiation Therapy

Integrating Early Rapid Post-peptide Receptor Radionuclide Therapy Quality Assurance Scan into the Outpatient Setting

Abstract

Sonia Mahajan, Joseph O’Donoghue, Wolfgang Weber and Lisa Bodei

Objective: To understand value of early rapid, quality-assurance (QA), post-therapy whole-body scan (Tx-WBS) in patients receiving peptide receptor radionuclide therapy (PRRT) in outpatient setting.
Methods: Sixteen patients with metastatic neuroendocrine tumors received PRRT and underwent Tx-WBS after each cycle. Early imaging (3 hour post-injection) was favored. Planar-images obtained on dual-headed gamma camera (speed 30 cm/min) were visually assessed and qualitatively compared with pre-therapy diagnostic scans. Retention% and lesion/spleen (L/S) ratios were calculated.
Results: Fifty three Tx-WBS were analyzed. No cutaneous contamination, extravasation or unexpected tracer distribution was observed. 46/53 (87%) Tx-WBS in 14/16 (88%) patients demonstrated uptake in metastatic lesions. No significant correlation was seen between L/S ratios and response on follow-up imaging. Qualitative assessment of follow-up images during four-cycles of PRRT provided preliminary estimate of disease course in 11/16 patients; with unexpected findings in 2.
Conclusion: In daily practice, especially in outpatient setting, an early QA post-PRRT scan proved effective for validating successful treatment and allowing preliminary disease monitoring, at no additional cost.