[en] The aim of the study was to correlate the results of the percentage of thyroid uptake (TU) with external detector type probe (PED) and a gammacamera (GC). Our hypothesis was that there are no significant differences between both measurements. In 91 patients (mean age ± SD =41 + 13 ; 77 women and 14 men) 24 hours % TU in both equipment was obtained, with the standard technique of our laboratory. Conclusions: Correlation was excellent . However there are significant difference between mean of both groups, GC values are higher than probe measurements.The difference is greater in those with less than 10% TU. Very interesting, there was no difference in the group with >10%TU. In clinical practice it is possible to perform the %TU measurement using a GC, taking into account the limitations noted above