RESUMEN
Objective To measure and calculate the dose distribution (tissue absorbed dose) of mouth floor area while using 125I to treat sublingual gland carcinoma.Methods Phantom of head and neck was used to place the 125I radioactive seeds to simulate the sublingual gland carcinoma treatment.125I radioactive seeds of 29.6 and 25.9 MBq per seed were used as two groups,with 31 seeds in each group,and prescribed dose (peripheral matched dose) was 120 Gy.Thermoluminescence dosimetry (TLD) was used to measure the absorbed dose value in the simulated target and adjacent area.Gafchromic Eriochrome Black T (EBT) film was used to draw the dose distribution curve.Results Dose absorbed in the target area,target area center and the adjacent area one centimeter away from target reached 160 Gy,390-500 Gy,and 90-170 Gy,respectively.Dose of the skin ranged from 25 to 81 Gy,dose of mandible ranged from 7.9 to 67 Gy.No radiation cold spot was found.Conclusions 125I seeds could achieve an effective therapeutic dose distribution of the target area for sublingual gland carcinoma.Dose absorbed in the adjacent tissue is under safety limit.The radiation dose at mandible is lower,reducing the possibility of radiation damage to the bone.