comparison of Three methods of calculation, experimental and monte carlo simulation in investigation of organ doses (Thyroid, sternum, cervical vertebra) in radioiodine Therapy

Radioiodine therapy is an effective method for treating thyroid cancer carcinoma, but it has some affects on normal tissues, hencedosimetry of vital organs is important to weigh the risks and benefits of this method. the aim of this study is to measure the absorbeddoses of important organs by monte carlo n particle (mcnp) simulation and comparing the results of different methods of dosimetryby performing a t-paired test. to calculate the absorbed dose of thyroid, sternum, and cervical vertebra using the mcnp code,*f8 tally was used. organs were simulated by using a neck phantom and medical internal radiation dosimetry (mird) method.finally, the results of mcnp, mird, and thermoluminescent dosimeter (tld) measurements were compared by spss software. theabsorbed dose obtained by monte carlo simulations for 100, 150, and 175 mci administered i was found to be 388.0, 427.9, and444.8 cgy for thyroid, 208.7, 230.1, and 239.3 cgy for sternum and 272.1, 299.9, and 312.1 cgy for cervical vertebra. the results ofpaired t-test were 0.24 for comparing tld dosimetry and mird calculation, 0.80 for mcnp simulation and mird, and 0.19 for tldand mcnp. the results showed no significant differences among three methods of monte carlo simulations, mird calculation anddirect experimental dosimetry using tld.