The estimation of body organs absorbed dose induced by 99mTc –MDP radiopharmaceutical in the patients undergoing bone scan by specific dosimetry and planar/SPECT hybrid method

Background: Bone scan is a nuclear medicine scan test. Methylene Diphosphonate (MDP) is used to bone scan. This combination is absorbed by bone and is excreted by the kidneys and bladder. The purpose of this study was to estimate the absorbed dose of organs in bone scan with injection MDP radiopharmaceutical by specific dosimetry and SPECT/planar hybrid method.Methods: 20 females who referred for bone disorders were examined and three planar images intervals of 1, 3 and 5 hours and one SPECT at 3 hours after injection were taken from them. The cumulative activity of the organs was obtained using the SPECT/planar hybrid method and then the absorbed dose was calculated using Mirdose software.Results: The mean absorbed dose due to 99mTc-MDP in women for heart wall (0.0026±0.0005), kidneys (0.043± 0.0072), liver (0.0034±0.0001), lungs (0.0024±0.0001), muscle (0.0028±0.0006), ovaries (0.0056±0.0004), spleen (0.0048±0.0003), urinary bladder wall (0.0680±0.0120), bones (0.0046± 0.0006) and reminder of the body (0.0031± 0.00096) mGy/MBq were obtained.Conclusion: Bladder, kidneys, ovaries, spleen, bones, liver, muscles, walls of the heart and lungs have the highest rates of absorbed dose in organs, respectively. Since the women studied in this study had different diseases, bone disorders, and biological characteristics, and some of them were metastatic due to the disease, this led to a different absorption of radiopharmaceuticals in the various organs of these patients, which caused the differences in the average absorbed dose of radiopharmaceuticals in their organs.