Thyroid Uptake Quantification on a New Generation of Gamma Camera

Planar and SPECT/CT scintigraphy will be performed on a new generation large field CZT gamma camera and thyroid uptake (TU) value will be calculated on planar acquisition for 23 consecutive patients referred in our department for hyperthyroidism. With a quantitative approach using attenuation, scatter correction and iterative algorithm with resolution recovery we will have the possibility to calculate the TU value with SPECT or SPECT/CT acquisitions. Our primary objective will be to evaluate the potential of a new large field 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. The secondary objective will be to analyze the diagnostic contribution of SPECT/CT images. To established this study it will be necessary to introduce cross-calibration factors performed from a thyroid phantom, for planar and SPECT acquisitions, to estimate the thyroid uptake values.