Background Neuroendocrine tumours (NET) overexpress somatostatin receptors on cell membranes. Imaging tests with somatostatin analogue tracers (SAT) are used for diagnosis and follow-up of NET and their metastases. Current guidelines recommend ¹¹¹ In(DTPA)-octreotide for this use but new alternatives are available, such as 99mTc-labelled SAT.

Purpose To study the consolidation of 99mTc-EDDA/HYNIC-TOC (99mTc-Tektrotyd) as SAT for the diagnose of NET in our centre.

Material and methods We analysed the requests for 99mTc-Tektrotyd received from the nuclear medicine service from November 2015 to September 2016. This tracer was not commercialised in our country until September 2016, so it was necessary to justify its use to obtain National Medicines Agency approval. We created a database which included: age, diagnose and reasons to justify 99mTc-Tektrotyd use, instead of ¹¹¹ In-labelled SAT in imaging tests. Data were retrieved from electronic health records, including clinical history and nuclear medicine service requests.

Results 32 requests were analysed: 28.125% of patients were <50 years old, 28.125% 50–70 years and 43.75% were older than 70 years. All patients had a NET diagnosis. The reasons for using the 99mTc-Tektroyd contrast were:

• 100% of patients had demonstrated mobility issues, specifically: home away from our centre (37.5%), advanced age (25%), poor health state (18.75%), patient’s comfort (6.25%), social issues (3.125%), mental health issues (3.125%) and family issues (3.125%). This was due to the fact that the imaging protocol of 111In is 2 days, 1 day longer than 99mTc-Tektroyd (1 day protocol).

• In 62.5% of cases, clinicians highlighted the importance of the ALARA principle (As Low As Reasonably Achievable) to reduce to a minimum exposure of patients to radioactive substances. The lower radiation dose associated with 99mTc-Tektrotyd imaging was particularly desirable for patients undergoing repeated scanning, such as cancer patients.

• In 31.25% of cases it was remarked that there was a higher resolution with the 99mTc-Tektroyd contrast, especially depending on the location of the tumour.

Conclusion A 1 day imaging protocol, lower radiation and high resolution are the main reasons that justify the use of 99mTc-Tektrotyd in imaging tests for NET patients. The pharmacy and therapeutics committee will propose including 99mTc-Tektrotyd in our therapeutic arsenal for diagnose of NET in our centre.

No conflict of interest