In this study, a dosimetric study was observed by using Cr-51 gamma radioisotope on liver scintigraphy. In this context, the source organ is determined as liver and it is aimed the evaluation of measuring doses from source organ to selected three critical organs (thyroid, gonad, and brain). An antropomorphic torso phantom has been preferred in the experiments. The measurements of critical organs doses were examined for chronic effects. Moreover, the chronic effect of Cr-51 radioisotope on critical organs was determined as cumulative dose. Thermoluminescent dosimeters were used for chronic dose assessment. In the experiments, lithium fluoride (LiF) (TLD-100) detectors were used and they were provided from Turkish Atomic Energy Authority -Cekmece Nuclear Research and Training Center and calibrated in there. Within this study, the evaluation of the cumulative doses by using Cr-51 for three critical organs was observed with an original setup by using anthropomorphic torso phantom experimentally.