Thyroid Uptake Quantification Validation on a Three-dimensional (3D) Cadmium-Zinc-Telluride (CZT) New Generation Gamma Camera

Clinical Evaluation of Thyroid Uptake Quantification With Technetium-99m (99mTc)-Pertechnetate: Comparison Between Gold Standard Planar and Quantitative 3D CZT Single Photon Emission Computed Tomography/Cumputed Tomography (SPECT/CT) Scintigraphy

Thyroid scintigraphy using technetium-99m (99mTc) pertechnetate is traditionally performed using planar imaging to estimate thyroid uptake. Recent developments in quantitative SPECT/CT allow direct activity quantification from three-dimensional tomographic acquisitions. The aim of this study was to evaluate the accuracy of thyroid uptake quantification obtained from 3D SPECT/CT compared with conventional planar image.

Planar and SPECT/CT scintigraphy will be performed on a new generation 3D CZT gamma camera and thyroid uptake (TU) value will be calculated on planar acquisition for 27 consecutive patients referred in the department of the investigators for hyper or hypothyroidism.

With a quantitative approach using attenuation, scatter correction and iterative algorithm (12 iterations and 8 subsets) with post filter Median Full Width at Half Maximum (FWHM=3), the TU value with SPECT or SPECT/CT acquisitions can be calculate.

The objective will be to evaluate the potential of a new 3D CZT gamma camera to estimate the thyroid uptake on SPECT (Tomography without attenuation correction) and SPECT/CT (tomography with attenuation correction) acquisitions compared with standard planar scintigraphy as a gold standard.

To established this study it will be necessary to introduce cross-calibration factors performed from homogeneous phantoms, for planar and 3D SPECT acquisitions, to estimate the thyroid uptake values.

Inclusion Criteria:

• hypothyroidism
• hyperthyroidism

Exclusion Criteria:

• Pregnant women