Abstarct: Myocardial perfusion imaging (MPI) is an entirely non-invasive technique to diagnose circulation and infarction disorders in patients who are suffering from cardiovascular diseases. It is a nuclear heart scan through the injection of labeled radiopharmaceuticals such as Tc-99m sestamibi (Cardiolite) and Thallous chloride Tl-201 with a particular dosage. The estimation of a dose absorbed by the patient's crucial body organs is a subject of interest, particularly in the discussion over maximum permissible dose. The rate of absorbed dose in organs that are sensitive to exposure such as cardiac cavities, breast, lungs, liver, kidney, and spleen, was investigated. The calculations were completed in two phases including simulation and empirical evaluation. In the first phase, dosimetry calculations were conducted through Monte Carlo N-Particle Transport (MCNPX2.6) in a standard ORAL MIRD female phantom using Tc-99m and TI-201radiopharmaceuticals. In the second phase, the evaluations were carried out using a single Thermoluminescent dosimeter (TLD) at the nuclear imaging center with the cooperation of patients of the same physical and anatomical features. The results obtained by this dosimeter were read after exposure and calibration. The results of both phases indicate the acceptability of evaluations with a difference of 5-12 percent for various tissues under both scenarios. The results are relatively acceptable, as with TLD features such as insusceptibility to environmental factors (humidity and temperature changes) and determination of environmental exposure as well as its applications in multiple settings. These radiopharmaceuticals generally act like a detector in the patient's body and the rate of its absorbed dose in organs that are sensitive to exposure is much lower than the maximum permissible dose according to the standard ICRP119, and in fact, the biological impacts of such radiopharmaceuticals are relatively safe.