Elsevier

European Journal of Radiology

Volume 80, Issue 2, November 2011, Pages e116-e119
European Journal of Radiology

Review
PET/CT with 68Gallium-DOTA-peptides in NET: An overview

https://doi.org/10.1016/j.ejrad.2010.07.022Get rights and content

Abstract

In the present review article we presented the major technical innovations regarding the diagnosis of NET with PET/CT 68Ga-DOTA-peptides compounds over conventional radiologic and scintigraphic imaging, discussing both the different types of radiopharmaceuticals commercially available, trying to making a comparison on the possible advantages and drawbacks of these radiopharmaceuticals, and providing also some technical recommendations to the radiologists and nuclear physicians for using these new methodology in an appropriate manner in the clinical setting.

Section snippets

68Ga-DOTA-TOC

68Ga-DOTA-TOC was the first tracer to be employed in NET imaging and was reported to present a high tumour to non-tumour contrast and a higher sensitivity compared to SRS [16], [17].

The study with the largest patients population (84 pts with NET), reported sensitivity (97%) for DOTA-TOC was superior to CT (61%) and SRS (52%) for the detection of NET lesions, especially in case of small tumours at nodal or bone level [18]. In particular, in a comparison study of 51 patients with well

68Ga-DOTA-NOC

68Ga-DOTA-NOC is also increasingly used in several centres: compared to DOTA-TOC, DOTA-NOC is able to bind with good affinity also to sst3 [13] and was reported to have a more favourable dosimetry [20]. The good sensitivity of 68Ga-DOTA-NOC was reported especially for small lesions, particularly at node and bone level [21], or in cases with an unusual anatomical localization [22].

68Ga-DOTA-NOC PET/CT was also reported to be more helpful than CT and SRS for the detection of unknown primary

68Ga-DOTA-TATE

68Ga-DOTA-TATE is characterized by a very high affinity for sst2 [13] with a considerably higher affinity than 111In-DTPAoctreotide [26].

In a recent paper, 51 patients (35 negative and 16 equivocal for uptake on SRS) were studied by 68Ga-DOTA-TATE PET. 68Ga-DOTA-TATE PET identified significantly more lesions than SRS and changed management in 36 patients (70.6%), who were subsequently deemed suitable for PRRT [27].

Comparison studies

A few studies in the literature compared the sensitivity of 68Ga-DOTA-peptides with metabolic tracers in NET patients, namely 18F-FDG and 18F-DOPA.

The only available study of direct comparison between 68Ga-DOTA-NOC and 18F-DOPA studied a limited patients population (13 pts): DOTA-NOC showed a higher number of lesions (71 vs. 45) and in more cases identified the site of the occult primary (6 vs. 2 of 8 non-operated cases) [28].

68Ga-DOTA-TATE was also compared with 18F-DOPA [29] and showed

PET/CT imaging protocol using 68GA-DOTA-peptides

PET/CT acquisition starts at 60 min after intravenous injection of approximately 100 MBq (75–250 MBq) of the radiolabeled peptide (such as 68Ga-DOTA-NOC, 68Ga-DOTA-TOC, etc.). The amount of injected radioactivity strictly depends on the daily production of the generator for each single elution (usually ranging between 300 and 700 MBq) and, of course, by the number of patients scanned per day.

Since sst are widely dispersed within the human body, different organs may be imaged by tracers binding to

Conclusions

The recent introduction of 68Ga-DOTA-peptides completely revolutioned the diagnostic approach to NET imaging with a direct impact on clinical management.

All described compounds (68Ga-DOTA-TOC, -NOC, -TATE) have been reported to be accurate for the localization of well differentiated NET lesions, performing better than CT and SRS.

PET assessment of NET with 68Ga-DOTA-peptides not only provides an accurate detection of even small-sized lesions, but also non-invasively provides valuable information

References (32)

  • W.D. Travis

    Reporting lung cancer pathology specimens. Impact of the anticipated 7th Edition TNM classification based on recommendations of the IASLC Staging Committee

    Histopathology

    (2009)
  • J.K. Ramage et al.

    UKNETwork for neuroendocrine tumours, guidelines for the management of gastroenteropancreatic neuroendocrine (including carcinoid) tumours

    Gut

    (2005)
  • E.P. Krenning et al.

    Somatostatin receptor scintigraphy with [111In-DTPA-D-Phe1]- and [123I-Tyr3]-octreotide: the Rotterdam experience with more than 1000 patients

    Eur J Nucl Med

    (1993)
  • S. Adams et al.

    Limited value of fluorine-18 fluorodeoxyglucose positron emission tomography for the imaging of neuroendocrine tumors

    Eur J Nucl Med

    (1998)
  • R. Cescato et al.

    Internalization of sst2, sst3, and sst5 receptors: effects of somatostatin agonists and antagonists

    J Nucl Med

    (2006)
  • P. Antunes et al.

    Are radiogallium-labelled DOTA-conjugated somatostatin analogues superior to those labelled with other radiometals?

    Eur J Nucl Med Mol Imaging

    (2007)
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