Lu-177 DOTATATE dosimetry for neuroendocrine tumor: single center experience

Lu-177 labelled with DOTATE is widely acceptable to treat Neuroendocrine Tumor (NET) disease and it better improvement of quality of patients' life since few years ago. However, the radionuclide toxicity becomes the main limitation of the (NET) treatment. Therefore, we performed a pilot study aimed to estimate radiation absorbed doses to dose-limiting organs to develop a systemic therapy with Lu-177 in NET patients. In this study, five set of planar whole body images was acquired every 0.5 hour, 4 hours, 24 hours, 48 hours and 72 hours after Lu-177 administrations. The planar image acquisition was done using Philip Brightview X with Medium Energy General Purpose Collimator (MEGP) collimator. All patients' images in Conjugate View (CV) format were transferred into PMOD 3.7 Software for Region of Interest (ROI) analysis. The ROI were drawn at selected organs such as kidneys, liver, spleen and bladder. This study found that the mean absorbed dose for kidneys 0.62 ± 0.26 Gy/GBq, liver 0.63 ± 0.28 Gy/GBq, spleen 0.83 ± 0.73 Gy/GBq and bladder 0.14 ± 0.07 Gy/GBq. The radionuclide kinetic for the whole body 99.7 ± 0.1 percent at 0.5 hours, 79.5 ± 10.7 percent at 4 hours, 56.6 ± 10.3 percent at 24 hours, 43.2 ± 7.9 percent at 48 hours and 37.1 ± 9.0 percent at 72 hours. This study verifies that this planar quantitative method able to determine organ at risk and the result line with other published data. (paper)