Comparative Evaluation of 99mTc-Octreotide for Diagnostic Accuracy Assessment and Localization of 177Lu-DOTA-TATE in Neuroendocrine Tumors

Naseer Ahmed; Ayesha Ammar; Kahkashan Bashir; Shazia Fatima; Muhammad Zia; Muhammad Adnan Saeed; Muhammad Faheem

doi:10.2174/1573405619666230209122923

Comparative Evaluation of 99mTc-Octreotide for Diagnostic Accuracy Assessment and Localization of 177Lu-DOTA-TATE in Neuroendocrine Tumors

Curr Med Imaging. 2023 Feb 9. doi: 10.2174/1573405619666230209122923. Online ahead of print.

Authors

Naseer Ahmed^{1

2}, Ayesha Ammar¹, Kahkashan Bashir¹, Shazia Fatima¹, Muhammad Zia², Muhammad Adnan Saeed¹, Muhammad Faheem¹

Affiliations

¹ Department of Nuclear Medicine, Nuclear Medicine, Oncology and Radiotherapy Institute (NORI) Hanna Road G-8/3 Islamabad.
² Department of Biotechnology, Quaid-I-Azam University, Islamabad.

PMID: 36757034
DOI: 10.2174/1573405619666230209122923

Abstract

Introduction: Neuroendocrine tumors, due to uncommon and multi-centric origin, pose a clinical challenge for their diagnosis and treatment. Developing countries where Ga-68 DOTA-TOC/NOC PET imaging is very limited and costly, 99mTc based SSR imaging can be used as the key tool for its diagnosis and assessment of therapy response. Hence we used two different 99mTc-radiopharmaceuticals for NET imaging designated as RP-1 and RP-2 for clinical assessment and peptide receptor therapy response of 177Lu-DOTA-TATE by manually synthesized acetate buffer. 99mTc- labeled RP-1 and RP-2 sensitivity, specificity; positive and negative predictive values were calculated and compared by SPECT/CT images for utilization in peptide receptor radionuclide therapy (PRRT).

Method: Sodium-pertechnetate was used for labeling both radiopharmaceuticals, while 177Lu nca (0.04 N HCl) DOTA-TATE was synthesized by 0.1M ammonium acetate/ascorbic acid. 75 patients of known primary NET imaging with RP-1 and RP-2 were evaluated for SRR avidity and 3 were selected for PRRT. All images were correlated with 68Ga-DOTA-TOC scan, histopathology, CT and/or MRI reports.

Results: Out of 75 patients, the somatostatin receptor imaging of 39 patients of neuro-endocrine was performed with RP-1, found 23 as true positive, 7 as true negative with sensitivity, specificity, PPV and NPV of 71.87%, 100%, 100% and 43.75%, whereas 36 images with RP-2 calculated 22 T/P, 6 as T/N, 8 as F/N, with 75.8%, 100%, 100% and 50% respectively. Their 177Lu-DOTA-TATE SPECT/CT revealed specific localization of therapeutic radionuclide.

Conclusion: 99mTc-imaging of RP-2, as compared to RP-1, had better efficiency and sensitivity and could effectively be used as an alternative to Ga-68 DOTA/TOC PET imaging and Lu-177 DOTA-TATE PRRT therapy response evaluation.

Keywords: 177Lu-DOTA-TATE; 99mTc base somatostatin receptor diagnostic agent; 99mTc-HYNIC-TATE/HYNIC-TOC; Comparative assessment of 99mTc-Octreotide.; Peptide Receptor Radionuclide Therapy.