open access

Vol 19, No 2 (2016)
Reviews
Published online: 2016-07-29
Submitted: 2016-07-26
Accepted: 2016-07-27
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Radiopharmaceuticals for somatostatin receptor imaging

Renata Mikołajczak, Helmut R. Maecke
DOI: 10.5603/NMR.2016.0024
·
Pubmed: 27479790
·
Nucl. Med. Rev 2016;19(2):126-132.

open access

Vol 19, No 2 (2016)
Reviews
Published online: 2016-07-29
Submitted: 2016-07-26
Accepted: 2016-07-27

Abstract

The aim of this review is to summarize the developments and briefly characterize the somatostatin analogs which are currently used for somatostatin receptor imaging in clinical routine or in early phase clinical trials.

Somatostatin (sst) receptor targeting with radiolabeled peptides has become an integral part in nuclear oncology during the last 20 years. This integration process has been initiated in Europe with the introduction to the market of 111In-DTPA-DPhe1-octreotide [111In-pentetreotide]. Introducing 99mTc in somatostatin receptor targeting radiopeptides resulted in much better image quality, higher sensitivity of tumor detection and lower mean effective dose for the examined patient. The next generation are 68Ga labeled somatostatin analogs. Due to the spatial resolution of PET technique and increasing number of PET scanners, the PET or PET/CT technique became very important in somatostatin receptor imaging. Until up to a couple of years ago the analogs of somatostatin were constructed aiming at their agonistic behavior, expecting that their internalization with the receptor acti­vated by the radiolabeled ligand and its retention within the tumor cell are crucial for efficient imaging and therapy. Recently it has been shown that the antagonists recognize more binding sites at the tumor cell membrane and hence offer an improved diagnostic efficacy, especially when the density of sst receptors is low. This approach may in future improve diagnostic value of somatostatin receptor imaging techniques. The developments in tracer design are followed by the improvements in imaging techniques. The new SPECT scanners offer resolution close to that of PET, which might open a new era for 99mTc and other SPECT radiotracers.

Abstract

The aim of this review is to summarize the developments and briefly characterize the somatostatin analogs which are currently used for somatostatin receptor imaging in clinical routine or in early phase clinical trials.

Somatostatin (sst) receptor targeting with radiolabeled peptides has become an integral part in nuclear oncology during the last 20 years. This integration process has been initiated in Europe with the introduction to the market of 111In-DTPA-DPhe1-octreotide [111In-pentetreotide]. Introducing 99mTc in somatostatin receptor targeting radiopeptides resulted in much better image quality, higher sensitivity of tumor detection and lower mean effective dose for the examined patient. The next generation are 68Ga labeled somatostatin analogs. Due to the spatial resolution of PET technique and increasing number of PET scanners, the PET or PET/CT technique became very important in somatostatin receptor imaging. Until up to a couple of years ago the analogs of somatostatin were constructed aiming at their agonistic behavior, expecting that their internalization with the receptor acti­vated by the radiolabeled ligand and its retention within the tumor cell are crucial for efficient imaging and therapy. Recently it has been shown that the antagonists recognize more binding sites at the tumor cell membrane and hence offer an improved diagnostic efficacy, especially when the density of sst receptors is low. This approach may in future improve diagnostic value of somatostatin receptor imaging techniques. The developments in tracer design are followed by the improvements in imaging techniques. The new SPECT scanners offer resolution close to that of PET, which might open a new era for 99mTc and other SPECT radiotracers.

Get Citation

Keywords

somatostatin, sst, somatostatin receptors, sstr, agonist, antagonist, 99mTc-EDDA/HYNIC-Tyr3-Octreotide, scintigraphy, imaging

About this article
Title

Radiopharmaceuticals for somatostatin receptor imaging

Journal

Nuclear Medicine Review

Issue

Vol 19, No 2 (2016)

Pages

126-132

Published online

2016-07-29

DOI

10.5603/NMR.2016.0024

Pubmed

27479790

Bibliographic record

Nucl. Med. Rev 2016;19(2):126-132.

Keywords

somatostatin
sst
somatostatin receptors
sstr
agonist
antagonist
99mTc-EDDA/HYNIC-Tyr3-Octreotide
scintigraphy
imaging

Authors

Renata Mikołajczak
Helmut R. Maecke

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