Abstract
1351
Objectives Background: Medullary thyroid cancer is a neuro endocrine tumour which originates from parafollicular or C cells of the thyroid gland. Neuroendocrine tumours express somatostatin receptors (SSTR) and radiolabelled Somatostatin analogues have been used for diagnostic imaging and treatment of the disease. Dual-modality imaging systems are configured by combining CT scanner with a gamma camera on a single gantry, which allows excellent registration of the two data sets with minimal registration errors. This provides functional and structural information in a single imaging session which would aid in localisation of the sites of tracer uptake and characterising them better. Aim: To assess the additional benefits of 111-Indium Octreotide SPECT/CT over planar and SPECT imaging in patients with suspicion of recurrent medullary thyroid cancer.
Methods We retrospectively analysed planar, SPECT and SPECT/CT images in 14 patients (11 females, 3 males) with medullary thyroid cancer who were referred for assessment of recurrent disease due to a rising Calcitonin level. Two nuclear medicine physicians assessed the scans independently. SPECT/CT scans were compared with planar and SPECT studies regarding accurate localisation and characterisation of any abnormal tracer uptake. In addition note was made of any incidental findings which were clinically significant.
Results 9 patients did not show any abnormal uptake of the tracer on planar, SPECT or SPECT/CT images. In the 5 patients there was improved localisation and characterisation noted in 80% of the patients (4/5). SPECT/CT showed clinical significant incidental findings in 50% of the patients (7/14) including lung nodules, non avid bone metastases, lymph nodes and sarcoid disease.
Conclusions SPECT/CT is a valuable tool for accurate localisation and characterisation of the tracer avid lesions in the medullary thyroid cancer. It can reveal significant clinical incidental findings which may alter patient’s management