Quantitative uptake in 99mTc-EDDA/HYNIC-TOC somatostatin receptor imaging – the effect of long-acting release somatostatin analogue therapy

Gemmell, A. J., Brown, C. M., Ray, S. and Small, A. (2023) Quantitative uptake in 99mTc-EDDA/HYNIC-TOC somatostatin receptor imaging – the effect of long-acting release somatostatin analogue therapy. Nuclear Medicine Communications, 44(11), pp. 944-952. (doi: 10.1097/MNM.0000000000001746) (PMID:37578312)

Abstract

Purpose: Withdrawal of long-acting release somatostatin analogue (LAR-SSA) treatment before somatostatin receptor imaging is based on empirical reasoning that it may block uptake at receptor sites. This study aims to quantify differences in uptake of 99mTc-EDDA/HYNIC-TOC between patients receiving LAR-SSA and those who were not. Methods: Quantification of 177 patients (55 on LAR-SSA) imaged with 99mTc-EDDA/HYNIC-TOC was performed, with analysis of pathological tissue and organs with physiological uptake using thresholded volumes of interest. Standardised uptake values (SUVs) and tumour/background (T/B) ratios were calculated and compared between the two patient groups. Results: SUVs were significantly lower for physiological organ uptake for patients on LAR-SSA (e.g. spleen: SUVmax 13.3 ± 5.9 versus 33.9 ± 9.0, P < 0.001); there was no significant difference for sites of pathological uptake (e.g. nodal metastases: SUVmax 19.2 ± 13.0 versus 17.4 ± 11.5, P = 0.552) apart from bone metastases (SUVmax 14.1 ± 13.5 versus 7.7 ± 8.0, P = 0.017) where it was significantly higher. Conclusion: LAR-SSA has an effect only on physiological organ uptake of 99mTc-EDDA/HYNIC-TOC, reducing uptake. It has no significant effect on pathological uptake for most sites of primary and metastatic disease. This should be taken into account if making quantitative measurements, calculating T/B ratios or assigning Krenning Scores. There is the potential for improved dosimetric results in Peptide Receptor Radionuclide Therapy by maintaining patients on LAR-SSA.

• Item Type: Articles
• Additional Information: NHS Greater Glasgow & Clyde Safe Haven supported this study through Research Ethics Committee (reference GSH22NE001).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ray, Professor Surajit and Small, Dr Sandy and Gemmell, Mr Alastair
• Authors: Gemmell, A. J., Brown, C. M., Ray, S., and Small, A.
• College/School: College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing; College of Science and Engineering > School of Mathematics and Statistics > Statistics
• Journal Name: Nuclear Medicine Communications
• Publisher: Lippincott, Williams and Wilkins
• ISSN: 0143-3636
• ISSN (Online): 1473-5628
• Published Online: 14 August 2023
• Copyright Holders: Copyright © 2023 Wolters Kluwer Health, Inc.
• First Published: First published in Nuclear Medicine Communications 44(11): 944-952
• Publisher Policy: Reproduced in accordance with the publisher copyright policy